[4/7] drm/msm/A6xx: Implement preemption for A7XX targets

Commit Message

Antonino Maniscalco Aug. 15, 2024, 6:26 p.m. UTC

This patch implements preemption feature for A6xx targets, this allows
the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
hardware as such supports multiple levels of preemption granularities,
ranging from coarse grained(ringbuffer level) to a more fine grained
such as draw-call level or a bin boundary level preemption. This patch
enables the basic preemption level, with more fine grained preemption
support to follow.

Signed-off-by: Sharat Masetty <[e-mail]>
Signed-off-by: Antonino Maniscalco <[e-mail]>
---
 drivers/gpu/drm/msm/Makefile              |   1 +
 drivers/gpu/drm/msm/adreno/a6xx_gpu.c     | 323 +++++++++++++++++++++-
 drivers/gpu/drm/msm/adreno/a6xx_gpu.h     | 168 ++++++++++++
 drivers/gpu/drm/msm/adreno/a6xx_preempt.c | 434 ++++++++++++++++++++++++++++++
 drivers/gpu/drm/msm/msm_ringbuffer.h      |   7 +
 5 files changed, 924 insertions(+), 9 deletions(-)

Comments

kernel test robot Aug. 16, 2024, 12:23 p.m. UTC | #1

Hi Antonino,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 7c626ce4bae1ac14f60076d00eafe71af30450ba]

url:    https://github.com/intel-lab-lkp/linux/commits/Antonino-Maniscalco/drm-msm-Fix-bv_fence-being-used-as-bv_rptr/20240816-023442
base:   7c626ce4bae1ac14f60076d00eafe71af30450ba
patch link:    https://lore.kernel.org/r/20240815-preemption-a750-t-v1-4-7bda26c34037%40gmail.com
patch subject: [PATCH 4/7] drm/msm/A6xx: Implement preemption for A7XX targets
config: i386-buildonly-randconfig-001-20240816 (https://download.01.org/0day-ci/archive/20240816/[e-mail]/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240816/[e-mail]/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[e-mail]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/

All warnings (new ones prefixed by >>):

   drivers/gpu/drm/msm/adreno/a6xx_preempt.c: In function 'update_wptr':
>> drivers/gpu/drm/msm/adreno/a6xx_preempt.c:49:24: warning: unused variable 'cur_wptr' [-Wunused-variable]
      49 |         uint32_t wptr, cur_wptr;
         |                        ^~~~~~~~


vim +/cur_wptr +49 drivers/gpu/drm/msm/adreno/a6xx_preempt.c

    44	
    45	/* Write the most recent wptr for the given ring into the hardware */
    46	static inline void update_wptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
    47	{
    48		unsigned long flags;
  > 49		uint32_t wptr, cur_wptr;
    50	
    51		if (!ring)
    52			return;
    53	
    54		spin_lock_irqsave(&ring->preempt_lock, flags);
    55	
    56		if (ring->skip_inline_wptr) {
    57			wptr = get_wptr(ring);
    58	
    59			gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
    60	
    61			ring->skip_inline_wptr = false;
    62		}
    63	
    64		spin_unlock_irqrestore(&ring->preempt_lock, flags);
    65	}
    66

kernel test robot Aug. 18, 2024, 12:34 a.m. UTC | #2

Hi Antonino,

kernel test robot noticed the following build errors:

[auto build test ERROR on 7c626ce4bae1ac14f60076d00eafe71af30450ba]

url:    https://github.com/intel-lab-lkp/linux/commits/Antonino-Maniscalco/drm-msm-Fix-bv_fence-being-used-as-bv_rptr/20240816-023442
base:   7c626ce4bae1ac14f60076d00eafe71af30450ba
patch link:    https://lore.kernel.org/r/20240815-preemption-a750-t-v1-4-7bda26c34037%40gmail.com
patch subject: [PATCH 4/7] drm/msm/A6xx: Implement preemption for A7XX targets
config: x86_64-buildonly-randconfig-001-20240818 (https://download.01.org/0day-ci/archive/20240818/[e-mail]/config)
compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240818/[e-mail]/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[e-mail]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/

All errors (new ones prefixed by >>):

>> drivers/gpu/drm/msm/adreno/a6xx_preempt.c:49:17: error: unused variable 'cur_wptr' [-Werror,-Wunused-variable]
      49 |         uint32_t wptr, cur_wptr;
         |                        ^~~~~~~~
   1 error generated.


vim +/cur_wptr +49 drivers/gpu/drm/msm/adreno/a6xx_preempt.c

    44	
    45	/* Write the most recent wptr for the given ring into the hardware */
    46	static inline void update_wptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
    47	{
    48		unsigned long flags;
  > 49		uint32_t wptr, cur_wptr;
    50	
    51		if (!ring)
    52			return;
    53	
    54		spin_lock_irqsave(&ring->preempt_lock, flags);
    55	
    56		if (ring->skip_inline_wptr) {
    57			wptr = get_wptr(ring);
    58	
    59			gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
    60	
    61			ring->skip_inline_wptr = false;
    62		}
    63	
    64		spin_unlock_irqrestore(&ring->preempt_lock, flags);
    65	}
    66

Akhil P Oommen Aug. 19, 2024, 8:08 p.m. UTC | #3

On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
> This patch implements preemption feature for A6xx targets, this allows
> the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
> hardware as such supports multiple levels of preemption granularities,
> ranging from coarse grained(ringbuffer level) to a more fine grained
> such as draw-call level or a bin boundary level preemption. This patch
> enables the basic preemption level, with more fine grained preemption
> support to follow.
> 
> Signed-off-by: Sharat Masetty <[e-mail]>
> Signed-off-by: Antonino Maniscalco <[e-mail]>
> ---

No postamble packets which resets perfcounters? It is necessary. Also, I
think we should disable preemption during profiling like we disable slumber.

-Akhil.

>  drivers/gpu/drm/msm/Makefile              |   1 +
>  drivers/gpu/drm/msm/adreno/a6xx_gpu.c     | 323 +++++++++++++++++++++-
>  drivers/gpu/drm/msm/adreno/a6xx_gpu.h     | 168 ++++++++++++
>  drivers/gpu/drm/msm/adreno/a6xx_preempt.c | 434 ++++++++++++++++++++++++++++++
>  drivers/gpu/drm/msm/msm_ringbuffer.h      |   7 +
>  5 files changed, 924 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile
> index f5e2838c6a76..32e915109a59 100644
> --- a/drivers/gpu/drm/msm/Makefile
> +++ b/drivers/gpu/drm/msm/Makefile
> @@ -23,6 +23,7 @@ adreno-y := \
>  	adreno/a6xx_gpu.o \
>  	adreno/a6xx_gmu.o \
>  	adreno/a6xx_hfi.o \
> +	adreno/a6xx_preempt.o \
>  
>  adreno-$(CONFIG_DEBUG_FS) += adreno/a5xx_debugfs.o \
>  
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> index 32a4faa93d7f..1a90db5759b8 100644
> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> @@ -16,6 +16,83 @@
>  
>  #define GPU_PAS_ID 13
>  
> +/* IFPC & Preemption static powerup restore list */
> +static const uint32_t a7xx_pwrup_reglist[] = {
> +	REG_A6XX_UCHE_TRAP_BASE,
> +	REG_A6XX_UCHE_TRAP_BASE + 1,
> +	REG_A6XX_UCHE_WRITE_THRU_BASE,
> +	REG_A6XX_UCHE_WRITE_THRU_BASE + 1,
> +	REG_A6XX_UCHE_GMEM_RANGE_MIN,
> +	REG_A6XX_UCHE_GMEM_RANGE_MIN + 1,
> +	REG_A6XX_UCHE_GMEM_RANGE_MAX,
> +	REG_A6XX_UCHE_GMEM_RANGE_MAX + 1,
> +	REG_A6XX_UCHE_CACHE_WAYS,
> +	REG_A6XX_UCHE_MODE_CNTL,
> +	REG_A6XX_RB_NC_MODE_CNTL,
> +	REG_A6XX_RB_CMP_DBG_ECO_CNTL,
> +	REG_A7XX_GRAS_NC_MODE_CNTL,
> +	REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE,
> +	REG_A6XX_UCHE_GBIF_GX_CONFIG,
> +	REG_A6XX_UCHE_CLIENT_PF,
> +};
> +
> +static const uint32_t a7xx_ifpc_pwrup_reglist[] = {
> +	REG_A6XX_TPL1_NC_MODE_CNTL,
> +	REG_A6XX_SP_NC_MODE_CNTL,
> +	REG_A6XX_CP_DBG_ECO_CNTL,
> +	REG_A6XX_CP_PROTECT_CNTL,
> +	REG_A6XX_CP_PROTECT(0),
> +	REG_A6XX_CP_PROTECT(1),
> +	REG_A6XX_CP_PROTECT(2),
> +	REG_A6XX_CP_PROTECT(3),
> +	REG_A6XX_CP_PROTECT(4),
> +	REG_A6XX_CP_PROTECT(5),
> +	REG_A6XX_CP_PROTECT(6),
> +	REG_A6XX_CP_PROTECT(7),
> +	REG_A6XX_CP_PROTECT(8),
> +	REG_A6XX_CP_PROTECT(9),
> +	REG_A6XX_CP_PROTECT(10),
> +	REG_A6XX_CP_PROTECT(11),
> +	REG_A6XX_CP_PROTECT(12),
> +	REG_A6XX_CP_PROTECT(13),
> +	REG_A6XX_CP_PROTECT(14),
> +	REG_A6XX_CP_PROTECT(15),
> +	REG_A6XX_CP_PROTECT(16),
> +	REG_A6XX_CP_PROTECT(17),
> +	REG_A6XX_CP_PROTECT(18),
> +	REG_A6XX_CP_PROTECT(19),
> +	REG_A6XX_CP_PROTECT(20),
> +	REG_A6XX_CP_PROTECT(21),
> +	REG_A6XX_CP_PROTECT(22),
> +	REG_A6XX_CP_PROTECT(23),
> +	REG_A6XX_CP_PROTECT(24),
> +	REG_A6XX_CP_PROTECT(25),
> +	REG_A6XX_CP_PROTECT(26),
> +	REG_A6XX_CP_PROTECT(27),
> +	REG_A6XX_CP_PROTECT(28),
> +	REG_A6XX_CP_PROTECT(29),
> +	REG_A6XX_CP_PROTECT(30),
> +	REG_A6XX_CP_PROTECT(31),
> +	REG_A6XX_CP_PROTECT(32),
> +	REG_A6XX_CP_PROTECT(33),
> +	REG_A6XX_CP_PROTECT(34),
> +	REG_A6XX_CP_PROTECT(35),
> +	REG_A6XX_CP_PROTECT(36),
> +	REG_A6XX_CP_PROTECT(37),
> +	REG_A6XX_CP_PROTECT(38),
> +	REG_A6XX_CP_PROTECT(39),
> +	REG_A6XX_CP_PROTECT(40),
> +	REG_A6XX_CP_PROTECT(41),
> +	REG_A6XX_CP_PROTECT(42),
> +	REG_A6XX_CP_PROTECT(43),
> +	REG_A6XX_CP_PROTECT(44),
> +	REG_A6XX_CP_PROTECT(45),
> +	REG_A6XX_CP_PROTECT(46),
> +	REG_A6XX_CP_PROTECT(47),
> +	REG_A6XX_CP_AHB_CNTL,
> +};
> +
> +
>  static inline bool _a6xx_check_idle(struct msm_gpu *gpu)
>  {
>  	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> @@ -68,6 +145,8 @@ static void update_shadow_rptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
>  
>  static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
>  {
> +	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> +	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
>  	uint32_t wptr;
>  	unsigned long flags;
>  
> @@ -81,12 +160,26 @@ static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
>  	/* Make sure to wrap wptr if we need to */
>  	wptr = get_wptr(ring);
>  
> -	spin_unlock_irqrestore(&ring->preempt_lock, flags);
> -
>  	/* Make sure everything is posted before making a decision */
>  	mb();
>  
> -	gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> +	/* Update HW if this is the current ring and we are not in preempt*/
> +	if (!a6xx_in_preempt(a6xx_gpu)) {
> +		/*
> +		 * Order the reads of the preempt state and cur_ring. This
> +		 * matches the barrier after writing cur_ring.
> +		 */
> +		rmb();
> +
> +		if (a6xx_gpu->cur_ring == ring)
> +			gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> +		else
> +			ring->skip_inline_wptr = true;
> +	} else {
> +		ring->skip_inline_wptr = true;
> +	}
> +
> +	spin_unlock_irqrestore(&ring->preempt_lock, flags);
>  }
>  
>  static void get_stats_counter(struct msm_ringbuffer *ring, u32 counter,
> @@ -138,12 +231,14 @@ static void a6xx_set_pagetable(struct a6xx_gpu *a6xx_gpu,
>  
>  	/*
>  	 * Write the new TTBR0 to the memstore. This is good for debugging.
> +	 * Needed for preemption
>  	 */
> -	OUT_PKT7(ring, CP_MEM_WRITE, 4);
> +	OUT_PKT7(ring, CP_MEM_WRITE, 5);
>  	OUT_RING(ring, CP_MEM_WRITE_0_ADDR_LO(lower_32_bits(memptr)));
>  	OUT_RING(ring, CP_MEM_WRITE_1_ADDR_HI(upper_32_bits(memptr)));
>  	OUT_RING(ring, lower_32_bits(ttbr));
> -	OUT_RING(ring, (asid << 16) | upper_32_bits(ttbr));
> +	OUT_RING(ring, upper_32_bits(ttbr));
> +	OUT_RING(ring, ctx->seqno);
>  
>  	/*
>  	 * Sync both threads after switching pagetables and enable BR only
> @@ -268,12 +363,55 @@ static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
>  	a6xx_flush(gpu, ring);
>  }
>  
> +static void a6xx_emit_set_pseudo_reg(struct msm_ringbuffer *ring,
> +		struct a6xx_gpu *a6xx_gpu, struct msm_gpu_submitqueue *queue)
> +{
> +	u64 preempt_offset_priv_secure;
> +
> +	OUT_PKT7(ring, CP_SET_PSEUDO_REG, 15);
> +
> +	OUT_RING(ring, SMMU_INFO);
> +	/* don't save SMMU, we write the record from the kernel instead */
> +	OUT_RING(ring, 0);
> +	OUT_RING(ring, 0);
> +
> +	/* privileged and non secure buffer save */
> +	OUT_RING(ring, NON_SECURE_SAVE_ADDR);
> +	OUT_RING(ring, lower_32_bits(
> +		a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE));
> +	OUT_RING(ring, upper_32_bits(
> +		a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE));
> +	OUT_RING(ring, SECURE_SAVE_ADDR);
> +	preempt_offset_priv_secure =
> +		PREEMPT_OFFSET_PRIV_SECURE(a6xx_gpu->base.info->preempt_record_size);
> +	OUT_RING(ring, lower_32_bits(
> +		a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure));
> +	OUT_RING(ring, upper_32_bits(
> +		a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure));
> +
> +	/* user context buffer save */
> +	OUT_RING(ring, NON_PRIV_SAVE_ADDR);
> +	if (queue) {
> +		OUT_RING(ring, lower_32_bits(queue->bo_iova));
> +		OUT_RING(ring, upper_32_bits(queue->bo_iova));
> +	} else {
> +		OUT_RING(ring, 0);
> +		OUT_RING(ring, 0);
> +	}
> +
> +	OUT_RING(ring, COUNTER);
> +	/* seems OK to set to 0 to disable it */
> +	OUT_RING(ring, 0);
> +	OUT_RING(ring, 0);
> +}
> +
>  static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
>  {
>  	unsigned int index = submit->seqno % MSM_GPU_SUBMIT_STATS_COUNT;
>  	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
>  	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
>  	struct msm_ringbuffer *ring = submit->ring;
> +	uint64_t scratch_dest = SCRATCH_USER_CTX_IOVA(ring->id, a6xx_gpu);
>  	unsigned int i, ibs = 0;
>  
>  	/*
> @@ -283,6 +421,25 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
>  	OUT_PKT7(ring, CP_THREAD_CONTROL, 1);
>  	OUT_RING(ring, CP_THREAD_CONTROL_0_SYNC_THREADS | CP_SET_THREAD_BR);
>  
> +	/*
> +	 * If preemption is enabled, then set the pseudo register for the save
> +	 * sequence
> +	 */
> +	if (gpu->nr_rings > 1) {
> +		a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, submit->queue);
> +
> +		/*
> +		 * Ask CP to save the user context buffer's iova address to a
> +		 * scratch memory region, this is needed if the CP preempts
> +		 * this ring in between this submit's IB list.
> +		 */
> +		OUT_PKT7(ring, CP_MEM_WRITE, 4);
> +		OUT_RING(ring, lower_32_bits(scratch_dest));
> +		OUT_RING(ring, upper_32_bits(scratch_dest));
> +		OUT_RING(ring, lower_32_bits(submit->queue->bo_iova));
> +		OUT_RING(ring, upper_32_bits(submit->queue->bo_iova));
> +	}
> +
>  	a6xx_set_pagetable(a6xx_gpu, ring, submit->queue->ctx);
>  
>  	get_stats_counter(ring, REG_A7XX_RBBM_PERFCTR_CP(0),
> @@ -376,6 +533,8 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
>  	OUT_RING(ring, upper_32_bits(rbmemptr(ring, bv_fence)));
>  	OUT_RING(ring, submit->seqno);
>  
> +	a6xx_gpu->last_seqno[ring->id] = submit->seqno;
> +
>  	/* write the ringbuffer timestamp */
>  	OUT_PKT7(ring, CP_EVENT_WRITE, 4);
>  	OUT_RING(ring, CACHE_CLEAN | CP_EVENT_WRITE_0_IRQ | BIT(27));
> @@ -389,10 +548,42 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
>  	OUT_PKT7(ring, CP_SET_MARKER, 1);
>  	OUT_RING(ring, 0x100); /* IFPC enable */
>  
> +	/* If preemption is enabled */
> +	if (gpu->nr_rings > 1) {
> +		/*
> +		 * Reset the scratch region as we are done with the
> +		 * IB list of this submission
> +		 */
> +		OUT_PKT7(ring, CP_MEM_WRITE, 4);
> +		OUT_RING(ring, lower_32_bits(scratch_dest));
> +		OUT_RING(ring, upper_32_bits(scratch_dest));
> +		OUT_RING(ring, 0x00);
> +		OUT_RING(ring, 0x00);
> +
> +		/* Yield the floor on command completion */
> +		OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
> +
> +		/*
> +		 * If dword[2:1] are non zero, they specify an address for
> +		 * the CP to write the value of dword[3] to on preemption
> +		 * complete. Write 0 to skip the write
> +		 */
> +		OUT_RING(ring, 0x00);
> +		OUT_RING(ring, 0x00);
> +		/* Data value - not used if the address above is 0 */
> +		OUT_RING(ring, 0x01);
> +		/* generate interrupt on preemption completion */
> +		OUT_RING(ring, 0x00);
> +	}
> +
> +
>  	trace_msm_gpu_submit_flush(submit,
>  		gpu_read64(gpu, REG_A6XX_CP_ALWAYS_ON_COUNTER));
>  
>  	a6xx_flush(gpu, ring);
> +
> +	/* Check to see if we need to start preemption */
> +	a6xx_preempt_trigger(gpu);
>  }
>  
>  static void a6xx_set_hwcg(struct msm_gpu *gpu, bool state)
> @@ -588,6 +779,89 @@ static void a6xx_set_ubwc_config(struct msm_gpu *gpu)
>  		  adreno_gpu->ubwc_config.min_acc_len << 23 | hbb_lo << 21);
>  }
>  
> +static void a7xx_patch_pwrup_reglist(struct msm_gpu *gpu)
> +{
> +	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> +	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> +	struct adreno_reglist_list reglist[2];
> +	void *ptr = a6xx_gpu->pwrup_reglist_ptr;
> +	struct cpu_gpu_lock *lock = ptr;
> +	u32 *dest = (u32 *)&lock->regs[0];
> +	int i, j;
> +
> +	lock->gpu_req = lock->cpu_req = lock->turn = 0;
> +	lock->ifpc_list_len = ARRAY_SIZE(a7xx_ifpc_pwrup_reglist);
> +	lock->preemption_list_len = ARRAY_SIZE(a7xx_pwrup_reglist);
> +
> +	/* Static IFPC-only registers */
> +	reglist[0].regs = a7xx_ifpc_pwrup_reglist;
> +	reglist[0].count = ARRAY_SIZE(a7xx_ifpc_pwrup_reglist);
> +	lock->ifpc_list_len = reglist[0].count;
> +
> +	/* Static IFPC + preemption registers */
> +	reglist[1].regs = a7xx_pwrup_reglist;
> +	reglist[1].count = ARRAY_SIZE(a7xx_pwrup_reglist);
> +	lock->preemption_list_len = reglist[1].count;
> +
> +	/*
> +	 * For each entry in each of the lists, write the offset and the current
> +	 * register value into the GPU buffer
> +	 */
> +	for (i = 0; i < 2; i++) {
> +		const u32 *r = reglist[i].regs;
> +
> +		for (j = 0; j < reglist[i].count; j++) {
> +			*dest++ = r[j];
> +			*dest++ = gpu_read(gpu, r[j]);
> +		}
> +	}
> +
> +	/*
> +	 * The overall register list is composed of
> +	 * 1. Static IFPC-only registers
> +	 * 2. Static IFPC + preemption registers
> +	 * 3. Dynamic IFPC + preemption registers (ex: perfcounter selects)
> +	 *
> +	 * The first two lists are static. Size of these lists are stored as
> +	 * number of pairs in ifpc_list_len and preemption_list_len
> +	 * respectively. With concurrent binning, Some of the perfcounter
> +	 * registers being virtualized, CP needs to know the pipe id to program
> +	 * the aperture inorder to restore the same. Thus, third list is a
> +	 * dynamic list with triplets as
> +	 * (<aperture, shifted 12 bits> <address> <data>), and the length is
> +	 * stored as number for triplets in dynamic_list_len.
> +	 */
> +	lock->dynamic_list_len = 0;
> +}
> +
> +static int a7xx_preempt_start(struct msm_gpu *gpu)
> +{
> +	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> +	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> +	struct msm_ringbuffer *ring = gpu->rb[0];
> +
> +	if (gpu->nr_rings <= 1)
> +		return 0;
> +
> +	/* Turn CP protection off */
> +	OUT_PKT7(ring, CP_SET_PROTECTED_MODE, 1);
> +	OUT_RING(ring, 0);
> +
> +	a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, NULL);
> +
> +	/* Yield the floor on command completion */
> +	OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
> +	OUT_RING(ring, 0x00);
> +	OUT_RING(ring, 0x00);
> +	OUT_RING(ring, 0x01);
> +	/* Generate interrupt on preemption completion */
> +	OUT_RING(ring, 0x00);
> +
> +	a6xx_flush(gpu, ring);
> +
> +	return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
> +}
> +
>  static int a6xx_cp_init(struct msm_gpu *gpu)
>  {
>  	struct msm_ringbuffer *ring = gpu->rb[0];
> @@ -619,6 +893,8 @@ static int a6xx_cp_init(struct msm_gpu *gpu)
>  
>  static int a7xx_cp_init(struct msm_gpu *gpu)
>  {
> +	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> +	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
>  	struct msm_ringbuffer *ring = gpu->rb[0];
>  	u32 mask;
>  
> @@ -626,6 +902,8 @@ static int a7xx_cp_init(struct msm_gpu *gpu)
>  	OUT_PKT7(ring, CP_THREAD_CONTROL, 1);
>  	OUT_RING(ring, BIT(27));
>  
> +	a7xx_patch_pwrup_reglist(gpu);
> +
>  	OUT_PKT7(ring, CP_ME_INIT, 7);
>  
>  	/* Use multiple HW contexts */
> @@ -656,11 +934,11 @@ static int a7xx_cp_init(struct msm_gpu *gpu)
>  
>  	/* *Don't* send a power up reg list for concurrent binning (TODO) */
>  	/* Lo address */
> -	OUT_RING(ring, 0x00000000);
> +	OUT_RING(ring, lower_32_bits(a6xx_gpu->pwrup_reglist_iova));
>  	/* Hi address */
> -	OUT_RING(ring, 0x00000000);
> +	OUT_RING(ring, upper_32_bits(a6xx_gpu->pwrup_reglist_iova));
>  	/* BIT(31) set => read the regs from the list */
> -	OUT_RING(ring, 0x00000000);
> +	OUT_RING(ring, BIT(31));
>  
>  	a6xx_flush(gpu, ring);
>  	return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
> @@ -784,6 +1062,16 @@ static int a6xx_ucode_load(struct msm_gpu *gpu)
>  		msm_gem_object_set_name(a6xx_gpu->shadow_bo, "shadow");
>  	}
>  
> +	a6xx_gpu->pwrup_reglist_ptr = msm_gem_kernel_new(gpu->dev, PAGE_SIZE,
> +							 MSM_BO_WC  | MSM_BO_MAP_PRIV,
> +							 gpu->aspace, &a6xx_gpu->pwrup_reglist_bo,
> +							 &a6xx_gpu->pwrup_reglist_iova);
> +
> +	if (IS_ERR(a6xx_gpu->pwrup_reglist_ptr))
> +		return PTR_ERR(a6xx_gpu->pwrup_reglist_ptr);
> +
> +	msm_gem_object_set_name(a6xx_gpu->pwrup_reglist_bo, "pwrup_reglist");
> +
>  	return 0;
>  }
>  
> @@ -1127,6 +1415,8 @@ static int hw_init(struct msm_gpu *gpu)
>  	if (a6xx_gpu->shadow_bo) {
>  		gpu_write64(gpu, REG_A6XX_CP_RB_RPTR_ADDR,
>  			shadowptr(a6xx_gpu, gpu->rb[0]));
> +		for (unsigned int i = 0; i < gpu->nr_rings; i++)
> +			a6xx_gpu->shadow[i] = 0;
>  	}
>  
>  	/* ..which means "always" on A7xx, also for BV shadow */
> @@ -1135,6 +1425,8 @@ static int hw_init(struct msm_gpu *gpu)
>  			    rbmemptr(gpu->rb[0], bv_rptr));
>  	}
>  
> +	a6xx_preempt_hw_init(gpu);
> +
>  	/* Always come up on rb 0 */
>  	a6xx_gpu->cur_ring = gpu->rb[0];
>  
> @@ -1180,6 +1472,10 @@ static int hw_init(struct msm_gpu *gpu)
>  out:
>  	if (adreno_has_gmu_wrapper(adreno_gpu))
>  		return ret;
> +
> +	/* Last step - yield the ringbuffer */
> +	a7xx_preempt_start(gpu);
> +
>  	/*
>  	 * Tell the GMU that we are done touching the GPU and it can start power
>  	 * management
> @@ -1557,8 +1853,13 @@ static irqreturn_t a6xx_irq(struct msm_gpu *gpu)
>  	if (status & A6XX_RBBM_INT_0_MASK_SWFUSEVIOLATION)
>  		a7xx_sw_fuse_violation_irq(gpu);
>  
> -	if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS)
> +	if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS) {
>  		msm_gpu_retire(gpu);
> +		a6xx_preempt_trigger(gpu);
> +	}
> +
> +	if (status & A6XX_RBBM_INT_0_MASK_CP_SW)
> +		a6xx_preempt_irq(gpu);
>  
>  	return IRQ_HANDLED;
>  }
> @@ -2165,6 +2466,8 @@ static const struct adreno_gpu_funcs funcs = {
>  		.active_ring = a6xx_active_ring,
>  		.irq = a6xx_irq,
>  		.destroy = a6xx_destroy,
> +		.submitqueue_setup = a6xx_preempt_submitqueue_setup,
> +		.submitqueue_close = a6xx_preempt_submitqueue_close,
>  #if defined(CONFIG_DRM_MSM_GPU_STATE)
>  		.show = a6xx_show,
>  #endif
> @@ -2331,6 +2634,8 @@ struct msm_gpu *a6xx_gpu_init(struct drm_device *dev)
>  				a6xx_fault_handler);
>  
>  	a6xx_calc_ubwc_config(adreno_gpu);
> +	/* Set up the preemption specific bits and pieces for each ringbuffer */
> +	a6xx_preempt_init(gpu);
>  
>  	return gpu;
>  }
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> index e3e5c53ae8af..652e49f01428 100644
> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> @@ -12,6 +12,31 @@
>  
>  extern bool hang_debug;
>  
> +struct cpu_gpu_lock {
> +	uint32_t gpu_req;
> +	uint32_t cpu_req;
> +	uint32_t turn;
> +	union {
> +		struct {
> +			uint16_t list_length;
> +			uint16_t list_offset;
> +		};
> +		struct {
> +			uint8_t ifpc_list_len;
> +			uint8_t preemption_list_len;
> +			uint16_t dynamic_list_len;
> +		};
> +	};
> +	uint64_t regs[62];
> +};
> +
> +struct adreno_reglist_list {
> +	/** @reg: List of register **/
> +	const u32 *regs;
> +	/** @count: Number of registers in the list **/
> +	u32 count;
> +};
> +
>  /**
>   * struct a6xx_info - a6xx specific information from device table
>   *
> @@ -31,6 +56,24 @@ struct a6xx_gpu {
>  	uint64_t sqe_iova;
>  
>  	struct msm_ringbuffer *cur_ring;
> +	struct msm_ringbuffer *next_ring;
> +
> +	struct drm_gem_object *preempt_bo[MSM_GPU_MAX_RINGS];
> +	void *preempt[MSM_GPU_MAX_RINGS];
> +	uint64_t preempt_iova[MSM_GPU_MAX_RINGS];
> +	uint32_t last_seqno[MSM_GPU_MAX_RINGS];
> +
> +	atomic_t preempt_state;
> +	spinlock_t eval_lock;
> +	struct timer_list preempt_timer;
> +
> +	unsigned int preempt_level;
> +	bool uses_gmem;
> +	bool skip_save_restore;
> +
> +	struct drm_gem_object *scratch_bo;
> +	void *scratch_ptr;
> +	uint64_t scratch_iova;
>  
>  	struct a6xx_gmu gmu;
>  
> @@ -38,6 +81,10 @@ struct a6xx_gpu {
>  	uint64_t shadow_iova;
>  	uint32_t *shadow;
>  
> +	struct drm_gem_object *pwrup_reglist_bo;
> +	void *pwrup_reglist_ptr;
> +	uint64_t pwrup_reglist_iova;
> +
>  	bool has_whereami;
>  
>  	void __iomem *llc_mmio;
> @@ -49,6 +96,108 @@ struct a6xx_gpu {
>  
>  #define to_a6xx_gpu(x) container_of(x, struct a6xx_gpu, base)
>  
> +#define SCRATCH_USER_CTX_IOVA(ring_id, a6xx_gpu) \
> +	(a6xx_gpu->scratch_iova + (ring_id * sizeof(uint64_t)))
> +
> +/*
> + * In order to do lockless preemption we use a simple state machine to progress
> + * through the process.
> + *
> + * PREEMPT_NONE - no preemption in progress.  Next state START.
> + * PREEMPT_START - The trigger is evaluating if preemption is possible. Next
> + * states: TRIGGERED, NONE
> + * PREEMPT_FINISH - An intermediate state before moving back to NONE. Next
> + * state: NONE.
> + * PREEMPT_TRIGGERED: A preemption has been executed on the hardware. Next
> + * states: FAULTED, PENDING
> + * PREEMPT_FAULTED: A preemption timed out (never completed). This will trigger
> + * recovery.  Next state: N/A
> + * PREEMPT_PENDING: Preemption complete interrupt fired - the callback is
> + * checking the success of the operation. Next state: FAULTED, NONE.
> + */
> +
> +enum a6xx_preempt_state {
> +	PREEMPT_NONE = 0,
> +	PREEMPT_START,
> +	PREEMPT_FINISH,
> +	PREEMPT_TRIGGERED,
> +	PREEMPT_FAULTED,
> +	PREEMPT_PENDING,
> +};
> +
> +/*
> + * struct a6xx_preempt_record is a shared buffer between the microcode and the
> + * CPU to store the state for preemption. The record itself is much larger
> + * (2112k) but most of that is used by the CP for storage.
> + *
> + * There is a preemption record assigned per ringbuffer. When the CPU triggers a
> + * preemption, it fills out the record with the useful information (wptr, ring
> + * base, etc) and the microcode uses that information to set up the CP following
> + * the preemption.  When a ring is switched out, the CP will save the ringbuffer
> + * state back to the record. In this way, once the records are properly set up
> + * the CPU can quickly switch back and forth between ringbuffers by only
> + * updating a few registers (often only the wptr).
> + *
> + * These are the CPU aware registers in the record:
> + * @magic: Must always be 0xAE399D6EUL
> + * @info: Type of the record - written 0 by the CPU, updated by the CP
> + * @errno: preemption error record
> + * @data: Data field in YIELD and SET_MARKER packets, Written and used by CP
> + * @cntl: Value of RB_CNTL written by CPU, save/restored by CP
> + * @rptr: Value of RB_RPTR written by CPU, save/restored by CP
> + * @wptr: Value of RB_WPTR written by CPU, save/restored by CP
> + * @_pad: Reserved/padding
> + * @rptr_addr: Value of RB_RPTR_ADDR_LO|HI written by CPU, save/restored by CP
> + * @rbase: Value of RB_BASE written by CPU, save/restored by CP
> + * @counter: GPU address of the storage area for the preemption counters
> + */
> +struct a6xx_preempt_record {
> +	u32 magic;
> +	u32 info;
> +	u32 errno;
> +	u32 data;
> +	u32 cntl;
> +	u32 rptr;
> +	u32 wptr;
> +	u32 _pad;
> +	u64 rptr_addr;
> +	u64 rbase;
> +	u64 counter;
> +	u64 bv_rptr_addr;
> +};
> +
> +#define A6XX_PREEMPT_RECORD_MAGIC 0xAE399D6EUL
> +
> +#define PREEMPT_RECORD_SIZE_FALLBACK(size) \
> +	((size) == 0 ? 4192 * SZ_1K : (size))
> +
> +#define PREEMPT_OFFSET_SMMU_INFO 0
> +#define PREEMPT_OFFSET_PRIV_NON_SECURE (PREEMPT_OFFSET_SMMU_INFO + 4096)
> +#define PREEMPT_OFFSET_PRIV_SECURE(size) \
> +	(PREEMPT_OFFSET_PRIV_NON_SECURE + PREEMPT_RECORD_SIZE_FALLBACK(size))
> +#define PREEMPT_SIZE(size) \
> +	(PREEMPT_OFFSET_PRIV_SECURE(size) + PREEMPT_RECORD_SIZE_FALLBACK(size))
> +
> +/*
> + * The preemption counter block is a storage area for the value of the
> + * preemption counters that are saved immediately before context switch. We
> + * append it on to the end of the allocation for the preemption record.
> + */
> +#define A6XX_PREEMPT_COUNTER_SIZE (16 * 4)
> +
> +#define A6XX_PREEMPT_USER_RECORD_SIZE (192 * 1024)
> +
> +struct a7xx_cp_smmu_info {
> +	u32 magic;
> +	u32 _pad4;
> +	u64 ttbr0;
> +	u32 asid;
> +	u32 context_idr;
> +	u32 context_bank;
> +};
> +
> +#define GEN7_CP_SMMU_INFO_MAGIC 0x241350d5UL
> +
>  /*
>   * Given a register and a count, return a value to program into
>   * REG_CP_PROTECT_REG(n) - this will block both reads and writes for
> @@ -106,6 +255,25 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
>  int a6xx_gmu_wrapper_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
>  void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu);
>  
> +void a6xx_preempt_init(struct msm_gpu *gpu);
> +void a6xx_preempt_hw_init(struct msm_gpu *gpu);
> +void a6xx_preempt_trigger(struct msm_gpu *gpu);
> +void a6xx_preempt_irq(struct msm_gpu *gpu);
> +void a6xx_preempt_fini(struct msm_gpu *gpu);
> +int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
> +		struct msm_gpu_submitqueue *queue);
> +void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
> +		struct msm_gpu_submitqueue *queue);
> +
> +/* Return true if we are in a preempt state */
> +static inline bool a6xx_in_preempt(struct a6xx_gpu *a6xx_gpu)
> +{
> +	int preempt_state = atomic_read(&a6xx_gpu->preempt_state);
> +
> +	return !(preempt_state == PREEMPT_NONE ||
> +			preempt_state == PREEMPT_FINISH);
> +}
> +
>  void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp,
>  		       bool suspended);
>  unsigned long a6xx_gmu_get_freq(struct msm_gpu *gpu);
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_preempt.c b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
> new file mode 100644
> index 000000000000..0d402a3bcf5a
> --- /dev/null
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
> @@ -0,0 +1,434 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2018, The Linux Foundation. All rights reserved. */
> +/* Copyright (c) 2023 Collabora, Ltd. */
> +/* Copyright (c) 2024 Valve Corporation */
> +
> +#include "msm_gem.h"
> +#include "a6xx_gpu.h"
> +#include "a6xx_gmu.xml.h"
> +#include "msm_mmu.h"
> +
> +#define FENCE_STATUS_WRITEDROPPED0_MASK 0x1
> +#define FENCE_STATUS_WRITEDROPPED1_MASK 0x2
> +
> +/*
> + * Try to transition the preemption state from old to new. Return
> + * true on success or false if the original state wasn't 'old'
> + */
> +static inline bool try_preempt_state(struct a6xx_gpu *a6xx_gpu,
> +		enum a6xx_preempt_state old, enum a6xx_preempt_state new)
> +{
> +	enum a6xx_preempt_state cur = atomic_cmpxchg(&a6xx_gpu->preempt_state,
> +		old, new);
> +
> +	return (cur == old);
> +}
> +
> +/*
> + * Force the preemption state to the specified state.  This is used in cases
> + * where the current state is known and won't change
> + */
> +static inline void set_preempt_state(struct a6xx_gpu *gpu,
> +		enum a6xx_preempt_state new)
> +{
> +	/*
> +	 * preempt_state may be read by other cores trying to trigger a
> +	 * preemption or in the interrupt handler so barriers are needed
> +	 * before...
> +	 */
> +	smp_mb__before_atomic();
> +	atomic_set(&gpu->preempt_state, new);
> +	/* ... and after*/
> +	smp_mb__after_atomic();
> +}
> +
> +/* Write the most recent wptr for the given ring into the hardware */
> +static inline void update_wptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> +{
> +	unsigned long flags;
> +	uint32_t wptr, cur_wptr;
> +
> +	if (!ring)
> +		return;
> +
> +	spin_lock_irqsave(&ring->preempt_lock, flags);
> +
> +	if (ring->skip_inline_wptr) {
> +		wptr = get_wptr(ring);
> +
> +		gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> +
> +		ring->skip_inline_wptr = false;
> +	}
> +
> +	spin_unlock_irqrestore(&ring->preempt_lock, flags);
> +}
> +
> +/* Return the highest priority ringbuffer with something in it */
> +static struct msm_ringbuffer *get_next_ring(struct msm_gpu *gpu)
> +{
> +	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> +	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> +
> +	unsigned long flags;
> +	int i;
> +
> +	for (i = 0; i < gpu->nr_rings; i++) {
> +		bool empty;
> +		struct msm_ringbuffer *ring = gpu->rb[i];
> +
> +		spin_lock_irqsave(&ring->preempt_lock, flags);
> +		empty = (get_wptr(ring) == gpu->funcs->get_rptr(gpu, ring));
> +		if (!empty && ring == a6xx_gpu->cur_ring)
> +			empty = ring->memptrs->fence == a6xx_gpu->last_seqno[i];
> +		spin_unlock_irqrestore(&ring->preempt_lock, flags);
> +
> +		if (!empty)
> +			return ring;
> +	}
> +
> +	return NULL;
> +}
> +
> +static void a6xx_preempt_timer(struct timer_list *t)
> +{
> +	struct a6xx_gpu *a6xx_gpu = from_timer(a6xx_gpu, t, preempt_timer);
> +	struct msm_gpu *gpu = &a6xx_gpu->base.base;
> +	struct drm_device *dev = gpu->dev;
> +
> +	if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_FAULTED))
> +		return;
> +
> +	dev_err(dev->dev, "%s: preemption timed out\n", gpu->name);
> +	kthread_queue_work(gpu->worker, &gpu->recover_work);
> +}
> +
> +void a6xx_preempt_irq(struct msm_gpu *gpu)
> +{
> +	uint32_t status;
> +	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> +	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> +	struct drm_device *dev = gpu->dev;
> +
> +	if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_PENDING))
> +		return;
> +
> +	/* Delete the preemption watchdog timer */
> +	del_timer(&a6xx_gpu->preempt_timer);
> +
> +	/*
> +	 * The hardware should be setting the stop bit of CP_CONTEXT_SWITCH_CNTL
> +	 * to zero before firing the interrupt, but there is a non zero chance
> +	 * of a hardware condition or a software race that could set it again
> +	 * before we have a chance to finish. If that happens, log and go for
> +	 * recovery
> +	 */
> +	status = gpu_read(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL);
> +	if (unlikely(status & 0x1)) {
> +		DRM_DEV_ERROR(&gpu->pdev->dev,
> +					  "!!!!!!!!!!!!!!!! preemption faulted !!!!!!!!!!!!!! irq\n");
> +		set_preempt_state(a6xx_gpu, PREEMPT_FAULTED);
> +		dev_err(dev->dev, "%s: Preemption failed to complete\n",
> +			gpu->name);
> +		kthread_queue_work(gpu->worker, &gpu->recover_work);
> +		return;
> +	}
> +
> +	a6xx_gpu->cur_ring = a6xx_gpu->next_ring;
> +	a6xx_gpu->next_ring = NULL;
> +
> +	/* Make sure the write to cur_ring is posted before the change in state */
> +	wmb();
> +
> +	set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
> +
> +	update_wptr(gpu, a6xx_gpu->cur_ring);
> +
> +	set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> +
> +	/*
> +	 * Retrigger preemption to avoid a deadlock that might occur when preemption
> +	 * is skipped due to it being already in flight when requested.
> +	 */
> +	a6xx_preempt_trigger(gpu);
> +}
> +
> +void a6xx_preempt_hw_init(struct msm_gpu *gpu)
> +{
> +	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> +	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> +	int i;
> +
> +	/* No preemption if we only have one ring */
> +	if (gpu->nr_rings == 1)
> +		return;
> +
> +	for (i = 0; i < gpu->nr_rings; i++) {
> +		struct a6xx_preempt_record *record_ptr =
> +			a6xx_gpu->preempt[i] + PREEMPT_OFFSET_PRIV_NON_SECURE;
> +		record_ptr->wptr = 0;
> +		record_ptr->rptr = 0;
> +		record_ptr->rptr_addr = shadowptr(a6xx_gpu, gpu->rb[i]);
> +		record_ptr->info = 0;
> +		record_ptr->data = 0;
> +		record_ptr->rbase = gpu->rb[i]->iova;
> +	}
> +
> +	/* Write a 0 to signal that we aren't switching pagetables */
> +	gpu_write64(gpu, REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO, 0);
> +
> +	/* Enable the GMEM save/restore feature for preemption */
> +	gpu_write(gpu, REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE, 0x1);
> +
> +	/* Reset the preemption state */
> +	set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> +
> +	spin_lock_init(&a6xx_gpu->eval_lock);
> +
> +	/* Always come up on rb 0 */
> +	a6xx_gpu->cur_ring = gpu->rb[0];
> +}
> +
> +void a6xx_preempt_trigger(struct msm_gpu *gpu)
> +{
> +	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> +	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> +	u64 preempt_offset_priv_secure;
> +	unsigned long flags;
> +	struct msm_ringbuffer *ring;
> +	uint64_t user_ctx_iova;
> +	unsigned int cntl;
> +
> +	if (gpu->nr_rings == 1)
> +		return;
> +
> +	/*
> +	 * Lock to make sure another thread attempting preemption doesn't skip it
> +	 * while we are still evaluating the next ring. This makes sure the other
> +	 * thread does start preemption if we abort it and avoids a soft lock.
> +	 */
> +	spin_lock_irqsave(&a6xx_gpu->eval_lock, flags);
> +
> +	/*
> +	 * Try to start preemption by moving from NONE to START. If
> +	 * unsuccessful, a preemption is already in flight
> +	 */
> +	if (!try_preempt_state(a6xx_gpu, PREEMPT_NONE, PREEMPT_START)) {
> +		spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> +		return;
> +	}
> +
> +	cntl = (((a6xx_gpu->preempt_level << 6) & 0xC0) |
> +		((a6xx_gpu->skip_save_restore << 9) & 0x200) |
> +		((a6xx_gpu->uses_gmem << 8) & 0x100) | 0x1);
> +
> +	/* Get the next ring to preempt to */
> +	ring = get_next_ring(gpu);
> +
> +	/*
> +	 * If no ring is populated or the highest priority ring is the current
> +	 * one do nothing except to update the wptr to the latest and greatest
> +	 */
> +	if (!ring || (a6xx_gpu->cur_ring == ring)) {
> +		set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
> +		update_wptr(gpu, a6xx_gpu->cur_ring);
> +		set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> +		spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> +		return;
> +	}
> +
> +	spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> +
> +	spin_lock_irqsave(&ring->preempt_lock, flags);
> +
> +	struct a7xx_cp_smmu_info *smmu_info_ptr =
> +		a6xx_gpu->preempt[ring->id] + PREEMPT_OFFSET_SMMU_INFO;
> +	struct a6xx_preempt_record *record_ptr =
> +		a6xx_gpu->preempt[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE;
> +	u64 ttbr0 = ring->memptrs->ttbr0;
> +	u32 context_idr = ring->memptrs->context_idr;
> +
> +	smmu_info_ptr->ttbr0 = ttbr0;
> +	smmu_info_ptr->context_idr = context_idr;
> +	record_ptr->wptr = get_wptr(ring);
> +
> +	/*
> +	 * The GPU will write the wptr we set above when we preempt. Reset
> +	 * skip_inline_wptr to make sure that we don't write WPTR to the same
> +	 * thing twice. It's still possible subsequent submissions will update
> +	 * wptr again, in which case they will set the flag to true. This has
> +	 * to be protected by the lock for setting the flag and updating wptr
> +	 * to be atomic.
> +	 */
> +	ring->skip_inline_wptr = false;
> +
> +	spin_unlock_irqrestore(&ring->preempt_lock, flags);
> +
> +	gpu_write64(gpu,
> +		REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO,
> +		a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_SMMU_INFO);
> +
> +	gpu_write64(gpu,
> +		REG_A6XX_CP_CONTEXT_SWITCH_PRIV_NON_SECURE_RESTORE_ADDR,
> +		a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE);
> +
> +	preempt_offset_priv_secure =
> +		PREEMPT_OFFSET_PRIV_SECURE(adreno_gpu->info->preempt_record_size);
> +	gpu_write64(gpu,
> +		REG_A6XX_CP_CONTEXT_SWITCH_PRIV_SECURE_RESTORE_ADDR,
> +		a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure);
> +
> +	/*
> +	 * Use the user context iova from the scratch memory that the CP may
> +	 * have written as part of the ring switch out.
> +	 */
> +	user_ctx_iova = *((uint64_t *)a6xx_gpu->scratch_ptr + ring->id);
> +
> +	gpu_write64(gpu,
> +		REG_A6XX_CP_CONTEXT_SWITCH_NON_PRIV_RESTORE_ADDR,
> +		user_ctx_iova);
> +
> +	a6xx_gpu->next_ring = ring;
> +
> +	/* Start a timer to catch a stuck preemption */
> +	mod_timer(&a6xx_gpu->preempt_timer, jiffies + msecs_to_jiffies(10000));
> +
> +	/* Set the preemption state to triggered */
> +	set_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED);
> +
> +	/* Make sure any previous writes to WPTR are posted */
> +	gpu_read(gpu, REG_A6XX_CP_RB_WPTR);
> +
> +	/* Make sure everything is written before hitting the button */
> +	wmb();
> +
> +	/* Trigger the preemption */
> +	gpu_write(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL, cntl);
> +}
> +
> +static int preempt_init_ring(struct a6xx_gpu *a6xx_gpu,
> +		struct msm_ringbuffer *ring)
> +{
> +	struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
> +	struct msm_gpu *gpu = &adreno_gpu->base;
> +	struct drm_gem_object *bo = NULL;
> +	phys_addr_t ttbr;
> +	u64 iova = 0;
> +	void *ptr;
> +	int asid;
> +
> +	ptr = msm_gem_kernel_new(gpu->dev,
> +		PREEMPT_SIZE(adreno_gpu->info->preempt_record_size),
> +		MSM_BO_WC | MSM_BO_MAP_PRIV, gpu->aspace, &bo, &iova);
> +
> +	memset(ptr, 0, PREEMPT_SIZE(adreno_gpu->info->preempt_record_size));
> +
> +	if (IS_ERR(ptr))
> +		return PTR_ERR(ptr);
> +
> +	a6xx_gpu->preempt_bo[ring->id] = bo;
> +	a6xx_gpu->preempt_iova[ring->id] = iova;
> +	a6xx_gpu->preempt[ring->id] = ptr;
> +
> +	struct a7xx_cp_smmu_info *smmu_info_ptr = ptr + PREEMPT_OFFSET_SMMU_INFO;
> +	struct a6xx_preempt_record *record_ptr = ptr + PREEMPT_OFFSET_PRIV_NON_SECURE;
> +
> +	msm_iommu_pagetable_params(gpu->aspace->mmu, &ttbr, &asid);
> +
> +	smmu_info_ptr->magic = GEN7_CP_SMMU_INFO_MAGIC;
> +	smmu_info_ptr->ttbr0 = ttbr;
> +	smmu_info_ptr->asid = 0xdecafbad;
> +	smmu_info_ptr->context_idr = 0;
> +
> +	/* Set up the defaults on the preemption record */
> +	record_ptr->magic = A6XX_PREEMPT_RECORD_MAGIC;
> +	record_ptr->info = 0;
> +	record_ptr->data = 0;
> +	record_ptr->rptr = 0;
> +	record_ptr->wptr = 0;
> +	record_ptr->cntl = MSM_GPU_RB_CNTL_DEFAULT;
> +	record_ptr->rbase = ring->iova;
> +	record_ptr->counter = 0;
> +	record_ptr->bv_rptr_addr = rbmemptr(ring, bv_rptr);
> +
> +	return 0;
> +}
> +
> +void a6xx_preempt_fini(struct msm_gpu *gpu)
> +{
> +	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> +	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> +	int i;
> +
> +	for (i = 0; i < gpu->nr_rings; i++)
> +		msm_gem_kernel_put(a6xx_gpu->preempt_bo[i], gpu->aspace);
> +}
> +
> +void a6xx_preempt_init(struct msm_gpu *gpu)
> +{
> +	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> +	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> +	int i;
> +
> +	/* No preemption if we only have one ring */
> +	if (gpu->nr_rings <= 1)
> +		return;
> +
> +	for (i = 0; i < gpu->nr_rings; i++) {
> +		if (preempt_init_ring(a6xx_gpu, gpu->rb[i]))
> +			goto fail;
> +	}
> +
> +	/* TODO: make this configurable? */
> +	a6xx_gpu->preempt_level = 1;
> +	a6xx_gpu->uses_gmem = 1;
> +	a6xx_gpu->skip_save_restore = 1;
> +
> +	a6xx_gpu->scratch_ptr  = msm_gem_kernel_new(gpu->dev,
> +			gpu->nr_rings * sizeof(uint64_t), MSM_BO_WC,
> +			gpu->aspace, &a6xx_gpu->scratch_bo,
> +			&a6xx_gpu->scratch_iova);
> +
> +	if (IS_ERR(a6xx_gpu->scratch_ptr))
> +		goto fail;
> +
> +	timer_setup(&a6xx_gpu->preempt_timer, a6xx_preempt_timer, 0);
> +
> +	return;
> +fail:
> +	/*
> +	 * On any failure our adventure is over. Clean up and
> +	 * set nr_rings to 1 to force preemption off
> +	 */
> +	a6xx_preempt_fini(gpu);
> +	gpu->nr_rings = 1;
> +
> +	return;
> +}
> +
> +void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
> +		struct msm_gpu_submitqueue *queue)
> +{
> +	if (!queue->bo)
> +		return;
> +
> +	msm_gem_kernel_put(queue->bo, gpu->aspace);
> +}
> +
> +int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
> +		struct msm_gpu_submitqueue *queue)
> +{
> +	void *ptr;
> +
> +	/*
> +	 * Create a per submitqueue buffer for the CP to save and restore user
> +	 * specific information such as the VPC streamout data.
> +	 */
> +	ptr = msm_gem_kernel_new(gpu->dev, A6XX_PREEMPT_USER_RECORD_SIZE,
> +			MSM_BO_WC, gpu->aspace, &queue->bo, &queue->bo_iova);
> +
> +	if (IS_ERR(ptr))
> +		return PTR_ERR(ptr);
> +
> +	return 0;
> +}
> diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.h b/drivers/gpu/drm/msm/msm_ringbuffer.h
> index 40791b2ade46..7dde6a312511 100644
> --- a/drivers/gpu/drm/msm/msm_ringbuffer.h
> +++ b/drivers/gpu/drm/msm/msm_ringbuffer.h
> @@ -36,6 +36,7 @@ struct msm_rbmemptrs {
>  
>  	volatile struct msm_gpu_submit_stats stats[MSM_GPU_SUBMIT_STATS_COUNT];
>  	volatile u64 ttbr0;
> +	volatile u32 context_idr;
>  };
>  
>  struct msm_cp_state {
> @@ -100,6 +101,12 @@ struct msm_ringbuffer {
>  	 * preemption.  Can be aquired from irq context.
>  	 */
>  	spinlock_t preempt_lock;
> +
> +	/*
> +	 * Whether we skipped writing wptr and it needs to be updated in the
> +	 * future when the ring becomes current.
> +	 */
> +	bool skip_inline_wptr;
>  };
>  
>  struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int id,
> 
> -- 
> 2.46.0
> 
>

Antonino Maniscalco Aug. 21, 2024, 2:34 p.m. UTC | #4

On 8/19/24 10:08 PM, Akhil P Oommen wrote:
> On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
>> This patch implements preemption feature for A6xx targets, this allows
>> the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
>> hardware as such supports multiple levels of preemption granularities,
>> ranging from coarse grained(ringbuffer level) to a more fine grained
>> such as draw-call level or a bin boundary level preemption. This patch
>> enables the basic preemption level, with more fine grained preemption
>> support to follow.
>>
>> Signed-off-by: Sharat Masetty <[e-mail]>
>> Signed-off-by: Antonino Maniscalco <[e-mail]>
>> ---
> 
> No postamble packets which resets perfcounters? It is necessary. Also, I
> think we should disable preemption during profiling like we disable slumber.
> 
> -Akhil.
> 

You mention that we disable slumber during profiling however I wasn't 
able to find code doing that. Can you please clarify which code you are 
referring to or a mechanism through which the kernel can know when we 
are profiling?

Best regards,

Connor Abbott Aug. 21, 2024, 4:02 p.m. UTC | #5

On Mon, Aug 19, 2024 at 9:09 PM Akhil P Oommen <[e-mail]> wrote:
>
> On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
> > This patch implements preemption feature for A6xx targets, this allows
> > the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
> > hardware as such supports multiple levels of preemption granularities,
> > ranging from coarse grained(ringbuffer level) to a more fine grained
> > such as draw-call level or a bin boundary level preemption. This patch
> > enables the basic preemption level, with more fine grained preemption
> > support to follow.
> >
> > Signed-off-by: Sharat Masetty <[e-mail]>
> > Signed-off-by: Antonino Maniscalco <[e-mail]>
> > ---
>
> No postamble packets which resets perfcounters? It is necessary. Also, I
> think we should disable preemption during profiling like we disable slumber.
>
> -Akhil.

I don't see anything in kgsl which disables preemption during
profiling. It disables resetting perfcounters when doing system-wide
profiling, like freedreno, and in that case I assume preempting is
fine because the system profiler has a complete view of everything and
should "see" preemptions through the traces. For something like
VK_KHR_performance_query I suppose we'd want to disable preemption
because we disable saving/restoring perf counters, but that has to
happen in userspace because the kernel doesn't know what userspace
does.

Connor

>
> >  drivers/gpu/drm/msm/Makefile              |   1 +
> >  drivers/gpu/drm/msm/adreno/a6xx_gpu.c     | 323 +++++++++++++++++++++-
> >  drivers/gpu/drm/msm/adreno/a6xx_gpu.h     | 168 ++++++++++++
> >  drivers/gpu/drm/msm/adreno/a6xx_preempt.c | 434 ++++++++++++++++++++++++++++++
> >  drivers/gpu/drm/msm/msm_ringbuffer.h      |   7 +
> >  5 files changed, 924 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile
> > index f5e2838c6a76..32e915109a59 100644
> > --- a/drivers/gpu/drm/msm/Makefile
> > +++ b/drivers/gpu/drm/msm/Makefile
> > @@ -23,6 +23,7 @@ adreno-y := \
> >       adreno/a6xx_gpu.o \
> >       adreno/a6xx_gmu.o \
> >       adreno/a6xx_hfi.o \
> > +     adreno/a6xx_preempt.o \
> >
> >  adreno-$(CONFIG_DEBUG_FS) += adreno/a5xx_debugfs.o \
> >
> > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > index 32a4faa93d7f..1a90db5759b8 100644
> > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > @@ -16,6 +16,83 @@
> >
> >  #define GPU_PAS_ID 13
> >
> > +/* IFPC & Preemption static powerup restore list */
> > +static const uint32_t a7xx_pwrup_reglist[] = {
> > +     REG_A6XX_UCHE_TRAP_BASE,
> > +     REG_A6XX_UCHE_TRAP_BASE + 1,
> > +     REG_A6XX_UCHE_WRITE_THRU_BASE,
> > +     REG_A6XX_UCHE_WRITE_THRU_BASE + 1,
> > +     REG_A6XX_UCHE_GMEM_RANGE_MIN,
> > +     REG_A6XX_UCHE_GMEM_RANGE_MIN + 1,
> > +     REG_A6XX_UCHE_GMEM_RANGE_MAX,
> > +     REG_A6XX_UCHE_GMEM_RANGE_MAX + 1,
> > +     REG_A6XX_UCHE_CACHE_WAYS,
> > +     REG_A6XX_UCHE_MODE_CNTL,
> > +     REG_A6XX_RB_NC_MODE_CNTL,
> > +     REG_A6XX_RB_CMP_DBG_ECO_CNTL,
> > +     REG_A7XX_GRAS_NC_MODE_CNTL,
> > +     REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE,
> > +     REG_A6XX_UCHE_GBIF_GX_CONFIG,
> > +     REG_A6XX_UCHE_CLIENT_PF,
> > +};
> > +
> > +static const uint32_t a7xx_ifpc_pwrup_reglist[] = {
> > +     REG_A6XX_TPL1_NC_MODE_CNTL,
> > +     REG_A6XX_SP_NC_MODE_CNTL,
> > +     REG_A6XX_CP_DBG_ECO_CNTL,
> > +     REG_A6XX_CP_PROTECT_CNTL,
> > +     REG_A6XX_CP_PROTECT(0),
> > +     REG_A6XX_CP_PROTECT(1),
> > +     REG_A6XX_CP_PROTECT(2),
> > +     REG_A6XX_CP_PROTECT(3),
> > +     REG_A6XX_CP_PROTECT(4),
> > +     REG_A6XX_CP_PROTECT(5),
> > +     REG_A6XX_CP_PROTECT(6),
> > +     REG_A6XX_CP_PROTECT(7),
> > +     REG_A6XX_CP_PROTECT(8),
> > +     REG_A6XX_CP_PROTECT(9),
> > +     REG_A6XX_CP_PROTECT(10),
> > +     REG_A6XX_CP_PROTECT(11),
> > +     REG_A6XX_CP_PROTECT(12),
> > +     REG_A6XX_CP_PROTECT(13),
> > +     REG_A6XX_CP_PROTECT(14),
> > +     REG_A6XX_CP_PROTECT(15),
> > +     REG_A6XX_CP_PROTECT(16),
> > +     REG_A6XX_CP_PROTECT(17),
> > +     REG_A6XX_CP_PROTECT(18),
> > +     REG_A6XX_CP_PROTECT(19),
> > +     REG_A6XX_CP_PROTECT(20),
> > +     REG_A6XX_CP_PROTECT(21),
> > +     REG_A6XX_CP_PROTECT(22),
> > +     REG_A6XX_CP_PROTECT(23),
> > +     REG_A6XX_CP_PROTECT(24),
> > +     REG_A6XX_CP_PROTECT(25),
> > +     REG_A6XX_CP_PROTECT(26),
> > +     REG_A6XX_CP_PROTECT(27),
> > +     REG_A6XX_CP_PROTECT(28),
> > +     REG_A6XX_CP_PROTECT(29),
> > +     REG_A6XX_CP_PROTECT(30),
> > +     REG_A6XX_CP_PROTECT(31),
> > +     REG_A6XX_CP_PROTECT(32),
> > +     REG_A6XX_CP_PROTECT(33),
> > +     REG_A6XX_CP_PROTECT(34),
> > +     REG_A6XX_CP_PROTECT(35),
> > +     REG_A6XX_CP_PROTECT(36),
> > +     REG_A6XX_CP_PROTECT(37),
> > +     REG_A6XX_CP_PROTECT(38),
> > +     REG_A6XX_CP_PROTECT(39),
> > +     REG_A6XX_CP_PROTECT(40),
> > +     REG_A6XX_CP_PROTECT(41),
> > +     REG_A6XX_CP_PROTECT(42),
> > +     REG_A6XX_CP_PROTECT(43),
> > +     REG_A6XX_CP_PROTECT(44),
> > +     REG_A6XX_CP_PROTECT(45),
> > +     REG_A6XX_CP_PROTECT(46),
> > +     REG_A6XX_CP_PROTECT(47),
> > +     REG_A6XX_CP_AHB_CNTL,
> > +};
> > +
> > +
> >  static inline bool _a6xx_check_idle(struct msm_gpu *gpu)
> >  {
> >       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > @@ -68,6 +145,8 @@ static void update_shadow_rptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> >
> >  static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> >  {
> > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> >       uint32_t wptr;
> >       unsigned long flags;
> >
> > @@ -81,12 +160,26 @@ static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> >       /* Make sure to wrap wptr if we need to */
> >       wptr = get_wptr(ring);
> >
> > -     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > -
> >       /* Make sure everything is posted before making a decision */
> >       mb();
> >
> > -     gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > +     /* Update HW if this is the current ring and we are not in preempt*/
> > +     if (!a6xx_in_preempt(a6xx_gpu)) {
> > +             /*
> > +              * Order the reads of the preempt state and cur_ring. This
> > +              * matches the barrier after writing cur_ring.
> > +              */
> > +             rmb();
> > +
> > +             if (a6xx_gpu->cur_ring == ring)
> > +                     gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > +             else
> > +                     ring->skip_inline_wptr = true;
> > +     } else {
> > +             ring->skip_inline_wptr = true;
> > +     }
> > +
> > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> >  }
> >
> >  static void get_stats_counter(struct msm_ringbuffer *ring, u32 counter,
> > @@ -138,12 +231,14 @@ static void a6xx_set_pagetable(struct a6xx_gpu *a6xx_gpu,
> >
> >       /*
> >        * Write the new TTBR0 to the memstore. This is good for debugging.
> > +      * Needed for preemption
> >        */
> > -     OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > +     OUT_PKT7(ring, CP_MEM_WRITE, 5);
> >       OUT_RING(ring, CP_MEM_WRITE_0_ADDR_LO(lower_32_bits(memptr)));
> >       OUT_RING(ring, CP_MEM_WRITE_1_ADDR_HI(upper_32_bits(memptr)));
> >       OUT_RING(ring, lower_32_bits(ttbr));
> > -     OUT_RING(ring, (asid << 16) | upper_32_bits(ttbr));
> > +     OUT_RING(ring, upper_32_bits(ttbr));
> > +     OUT_RING(ring, ctx->seqno);
> >
> >       /*
> >        * Sync both threads after switching pagetables and enable BR only
> > @@ -268,12 +363,55 @@ static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> >       a6xx_flush(gpu, ring);
> >  }
> >
> > +static void a6xx_emit_set_pseudo_reg(struct msm_ringbuffer *ring,
> > +             struct a6xx_gpu *a6xx_gpu, struct msm_gpu_submitqueue *queue)
> > +{
> > +     u64 preempt_offset_priv_secure;
> > +
> > +     OUT_PKT7(ring, CP_SET_PSEUDO_REG, 15);
> > +
> > +     OUT_RING(ring, SMMU_INFO);
> > +     /* don't save SMMU, we write the record from the kernel instead */
> > +     OUT_RING(ring, 0);
> > +     OUT_RING(ring, 0);
> > +
> > +     /* privileged and non secure buffer save */
> > +     OUT_RING(ring, NON_SECURE_SAVE_ADDR);
> > +     OUT_RING(ring, lower_32_bits(
> > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE));
> > +     OUT_RING(ring, upper_32_bits(
> > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE));
> > +     OUT_RING(ring, SECURE_SAVE_ADDR);
> > +     preempt_offset_priv_secure =
> > +             PREEMPT_OFFSET_PRIV_SECURE(a6xx_gpu->base.info->preempt_record_size);
> > +     OUT_RING(ring, lower_32_bits(
> > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure));
> > +     OUT_RING(ring, upper_32_bits(
> > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure));
> > +
> > +     /* user context buffer save */
> > +     OUT_RING(ring, NON_PRIV_SAVE_ADDR);
> > +     if (queue) {
> > +             OUT_RING(ring, lower_32_bits(queue->bo_iova));
> > +             OUT_RING(ring, upper_32_bits(queue->bo_iova));
> > +     } else {
> > +             OUT_RING(ring, 0);
> > +             OUT_RING(ring, 0);
> > +     }
> > +
> > +     OUT_RING(ring, COUNTER);
> > +     /* seems OK to set to 0 to disable it */
> > +     OUT_RING(ring, 0);
> > +     OUT_RING(ring, 0);
> > +}
> > +
> >  static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> >  {
> >       unsigned int index = submit->seqno % MSM_GPU_SUBMIT_STATS_COUNT;
> >       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> >       struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> >       struct msm_ringbuffer *ring = submit->ring;
> > +     uint64_t scratch_dest = SCRATCH_USER_CTX_IOVA(ring->id, a6xx_gpu);
> >       unsigned int i, ibs = 0;
> >
> >       /*
> > @@ -283,6 +421,25 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> >       OUT_PKT7(ring, CP_THREAD_CONTROL, 1);
> >       OUT_RING(ring, CP_THREAD_CONTROL_0_SYNC_THREADS | CP_SET_THREAD_BR);
> >
> > +     /*
> > +      * If preemption is enabled, then set the pseudo register for the save
> > +      * sequence
> > +      */
> > +     if (gpu->nr_rings > 1) {
> > +             a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, submit->queue);
> > +
> > +             /*
> > +              * Ask CP to save the user context buffer's iova address to a
> > +              * scratch memory region, this is needed if the CP preempts
> > +              * this ring in between this submit's IB list.
> > +              */
> > +             OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > +             OUT_RING(ring, lower_32_bits(scratch_dest));
> > +             OUT_RING(ring, upper_32_bits(scratch_dest));
> > +             OUT_RING(ring, lower_32_bits(submit->queue->bo_iova));
> > +             OUT_RING(ring, upper_32_bits(submit->queue->bo_iova));
> > +     }
> > +
> >       a6xx_set_pagetable(a6xx_gpu, ring, submit->queue->ctx);
> >
> >       get_stats_counter(ring, REG_A7XX_RBBM_PERFCTR_CP(0),
> > @@ -376,6 +533,8 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> >       OUT_RING(ring, upper_32_bits(rbmemptr(ring, bv_fence)));
> >       OUT_RING(ring, submit->seqno);
> >
> > +     a6xx_gpu->last_seqno[ring->id] = submit->seqno;
> > +
> >       /* write the ringbuffer timestamp */
> >       OUT_PKT7(ring, CP_EVENT_WRITE, 4);
> >       OUT_RING(ring, CACHE_CLEAN | CP_EVENT_WRITE_0_IRQ | BIT(27));
> > @@ -389,10 +548,42 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> >       OUT_PKT7(ring, CP_SET_MARKER, 1);
> >       OUT_RING(ring, 0x100); /* IFPC enable */
> >
> > +     /* If preemption is enabled */
> > +     if (gpu->nr_rings > 1) {
> > +             /*
> > +              * Reset the scratch region as we are done with the
> > +              * IB list of this submission
> > +              */
> > +             OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > +             OUT_RING(ring, lower_32_bits(scratch_dest));
> > +             OUT_RING(ring, upper_32_bits(scratch_dest));
> > +             OUT_RING(ring, 0x00);
> > +             OUT_RING(ring, 0x00);
> > +
> > +             /* Yield the floor on command completion */
> > +             OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
> > +
> > +             /*
> > +              * If dword[2:1] are non zero, they specify an address for
> > +              * the CP to write the value of dword[3] to on preemption
> > +              * complete. Write 0 to skip the write
> > +              */
> > +             OUT_RING(ring, 0x00);
> > +             OUT_RING(ring, 0x00);
> > +             /* Data value - not used if the address above is 0 */
> > +             OUT_RING(ring, 0x01);
> > +             /* generate interrupt on preemption completion */
> > +             OUT_RING(ring, 0x00);
> > +     }
> > +
> > +
> >       trace_msm_gpu_submit_flush(submit,
> >               gpu_read64(gpu, REG_A6XX_CP_ALWAYS_ON_COUNTER));
> >
> >       a6xx_flush(gpu, ring);
> > +
> > +     /* Check to see if we need to start preemption */
> > +     a6xx_preempt_trigger(gpu);
> >  }
> >
> >  static void a6xx_set_hwcg(struct msm_gpu *gpu, bool state)
> > @@ -588,6 +779,89 @@ static void a6xx_set_ubwc_config(struct msm_gpu *gpu)
> >                 adreno_gpu->ubwc_config.min_acc_len << 23 | hbb_lo << 21);
> >  }
> >
> > +static void a7xx_patch_pwrup_reglist(struct msm_gpu *gpu)
> > +{
> > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > +     struct adreno_reglist_list reglist[2];
> > +     void *ptr = a6xx_gpu->pwrup_reglist_ptr;
> > +     struct cpu_gpu_lock *lock = ptr;
> > +     u32 *dest = (u32 *)&lock->regs[0];
> > +     int i, j;
> > +
> > +     lock->gpu_req = lock->cpu_req = lock->turn = 0;
> > +     lock->ifpc_list_len = ARRAY_SIZE(a7xx_ifpc_pwrup_reglist);
> > +     lock->preemption_list_len = ARRAY_SIZE(a7xx_pwrup_reglist);
> > +
> > +     /* Static IFPC-only registers */
> > +     reglist[0].regs = a7xx_ifpc_pwrup_reglist;
> > +     reglist[0].count = ARRAY_SIZE(a7xx_ifpc_pwrup_reglist);
> > +     lock->ifpc_list_len = reglist[0].count;
> > +
> > +     /* Static IFPC + preemption registers */
> > +     reglist[1].regs = a7xx_pwrup_reglist;
> > +     reglist[1].count = ARRAY_SIZE(a7xx_pwrup_reglist);
> > +     lock->preemption_list_len = reglist[1].count;
> > +
> > +     /*
> > +      * For each entry in each of the lists, write the offset and the current
> > +      * register value into the GPU buffer
> > +      */
> > +     for (i = 0; i < 2; i++) {
> > +             const u32 *r = reglist[i].regs;
> > +
> > +             for (j = 0; j < reglist[i].count; j++) {
> > +                     *dest++ = r[j];
> > +                     *dest++ = gpu_read(gpu, r[j]);
> > +             }
> > +     }
> > +
> > +     /*
> > +      * The overall register list is composed of
> > +      * 1. Static IFPC-only registers
> > +      * 2. Static IFPC + preemption registers
> > +      * 3. Dynamic IFPC + preemption registers (ex: perfcounter selects)
> > +      *
> > +      * The first two lists are static. Size of these lists are stored as
> > +      * number of pairs in ifpc_list_len and preemption_list_len
> > +      * respectively. With concurrent binning, Some of the perfcounter
> > +      * registers being virtualized, CP needs to know the pipe id to program
> > +      * the aperture inorder to restore the same. Thus, third list is a
> > +      * dynamic list with triplets as
> > +      * (<aperture, shifted 12 bits> <address> <data>), and the length is
> > +      * stored as number for triplets in dynamic_list_len.
> > +      */
> > +     lock->dynamic_list_len = 0;
> > +}
> > +
> > +static int a7xx_preempt_start(struct msm_gpu *gpu)
> > +{
> > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > +     struct msm_ringbuffer *ring = gpu->rb[0];
> > +
> > +     if (gpu->nr_rings <= 1)
> > +             return 0;
> > +
> > +     /* Turn CP protection off */
> > +     OUT_PKT7(ring, CP_SET_PROTECTED_MODE, 1);
> > +     OUT_RING(ring, 0);
> > +
> > +     a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, NULL);
> > +
> > +     /* Yield the floor on command completion */
> > +     OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
> > +     OUT_RING(ring, 0x00);
> > +     OUT_RING(ring, 0x00);
> > +     OUT_RING(ring, 0x01);
> > +     /* Generate interrupt on preemption completion */
> > +     OUT_RING(ring, 0x00);
> > +
> > +     a6xx_flush(gpu, ring);
> > +
> > +     return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
> > +}
> > +
> >  static int a6xx_cp_init(struct msm_gpu *gpu)
> >  {
> >       struct msm_ringbuffer *ring = gpu->rb[0];
> > @@ -619,6 +893,8 @@ static int a6xx_cp_init(struct msm_gpu *gpu)
> >
> >  static int a7xx_cp_init(struct msm_gpu *gpu)
> >  {
> > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> >       struct msm_ringbuffer *ring = gpu->rb[0];
> >       u32 mask;
> >
> > @@ -626,6 +902,8 @@ static int a7xx_cp_init(struct msm_gpu *gpu)
> >       OUT_PKT7(ring, CP_THREAD_CONTROL, 1);
> >       OUT_RING(ring, BIT(27));
> >
> > +     a7xx_patch_pwrup_reglist(gpu);
> > +
> >       OUT_PKT7(ring, CP_ME_INIT, 7);
> >
> >       /* Use multiple HW contexts */
> > @@ -656,11 +934,11 @@ static int a7xx_cp_init(struct msm_gpu *gpu)
> >
> >       /* *Don't* send a power up reg list for concurrent binning (TODO) */
> >       /* Lo address */
> > -     OUT_RING(ring, 0x00000000);
> > +     OUT_RING(ring, lower_32_bits(a6xx_gpu->pwrup_reglist_iova));
> >       /* Hi address */
> > -     OUT_RING(ring, 0x00000000);
> > +     OUT_RING(ring, upper_32_bits(a6xx_gpu->pwrup_reglist_iova));
> >       /* BIT(31) set => read the regs from the list */
> > -     OUT_RING(ring, 0x00000000);
> > +     OUT_RING(ring, BIT(31));
> >
> >       a6xx_flush(gpu, ring);
> >       return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
> > @@ -784,6 +1062,16 @@ static int a6xx_ucode_load(struct msm_gpu *gpu)
> >               msm_gem_object_set_name(a6xx_gpu->shadow_bo, "shadow");
> >       }
> >
> > +     a6xx_gpu->pwrup_reglist_ptr = msm_gem_kernel_new(gpu->dev, PAGE_SIZE,
> > +                                                      MSM_BO_WC  | MSM_BO_MAP_PRIV,
> > +                                                      gpu->aspace, &a6xx_gpu->pwrup_reglist_bo,
> > +                                                      &a6xx_gpu->pwrup_reglist_iova);
> > +
> > +     if (IS_ERR(a6xx_gpu->pwrup_reglist_ptr))
> > +             return PTR_ERR(a6xx_gpu->pwrup_reglist_ptr);
> > +
> > +     msm_gem_object_set_name(a6xx_gpu->pwrup_reglist_bo, "pwrup_reglist");
> > +
> >       return 0;
> >  }
> >
> > @@ -1127,6 +1415,8 @@ static int hw_init(struct msm_gpu *gpu)
> >       if (a6xx_gpu->shadow_bo) {
> >               gpu_write64(gpu, REG_A6XX_CP_RB_RPTR_ADDR,
> >                       shadowptr(a6xx_gpu, gpu->rb[0]));
> > +             for (unsigned int i = 0; i < gpu->nr_rings; i++)
> > +                     a6xx_gpu->shadow[i] = 0;
> >       }
> >
> >       /* ..which means "always" on A7xx, also for BV shadow */
> > @@ -1135,6 +1425,8 @@ static int hw_init(struct msm_gpu *gpu)
> >                           rbmemptr(gpu->rb[0], bv_rptr));
> >       }
> >
> > +     a6xx_preempt_hw_init(gpu);
> > +
> >       /* Always come up on rb 0 */
> >       a6xx_gpu->cur_ring = gpu->rb[0];
> >
> > @@ -1180,6 +1472,10 @@ static int hw_init(struct msm_gpu *gpu)
> >  out:
> >       if (adreno_has_gmu_wrapper(adreno_gpu))
> >               return ret;
> > +
> > +     /* Last step - yield the ringbuffer */
> > +     a7xx_preempt_start(gpu);
> > +
> >       /*
> >        * Tell the GMU that we are done touching the GPU and it can start power
> >        * management
> > @@ -1557,8 +1853,13 @@ static irqreturn_t a6xx_irq(struct msm_gpu *gpu)
> >       if (status & A6XX_RBBM_INT_0_MASK_SWFUSEVIOLATION)
> >               a7xx_sw_fuse_violation_irq(gpu);
> >
> > -     if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS)
> > +     if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS) {
> >               msm_gpu_retire(gpu);
> > +             a6xx_preempt_trigger(gpu);
> > +     }
> > +
> > +     if (status & A6XX_RBBM_INT_0_MASK_CP_SW)
> > +             a6xx_preempt_irq(gpu);
> >
> >       return IRQ_HANDLED;
> >  }
> > @@ -2165,6 +2466,8 @@ static const struct adreno_gpu_funcs funcs = {
> >               .active_ring = a6xx_active_ring,
> >               .irq = a6xx_irq,
> >               .destroy = a6xx_destroy,
> > +             .submitqueue_setup = a6xx_preempt_submitqueue_setup,
> > +             .submitqueue_close = a6xx_preempt_submitqueue_close,
> >  #if defined(CONFIG_DRM_MSM_GPU_STATE)
> >               .show = a6xx_show,
> >  #endif
> > @@ -2331,6 +2634,8 @@ struct msm_gpu *a6xx_gpu_init(struct drm_device *dev)
> >                               a6xx_fault_handler);
> >
> >       a6xx_calc_ubwc_config(adreno_gpu);
> > +     /* Set up the preemption specific bits and pieces for each ringbuffer */
> > +     a6xx_preempt_init(gpu);
> >
> >       return gpu;
> >  }
> > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > index e3e5c53ae8af..652e49f01428 100644
> > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > @@ -12,6 +12,31 @@
> >
> >  extern bool hang_debug;
> >
> > +struct cpu_gpu_lock {
> > +     uint32_t gpu_req;
> > +     uint32_t cpu_req;
> > +     uint32_t turn;
> > +     union {
> > +             struct {
> > +                     uint16_t list_length;
> > +                     uint16_t list_offset;
> > +             };
> > +             struct {
> > +                     uint8_t ifpc_list_len;
> > +                     uint8_t preemption_list_len;
> > +                     uint16_t dynamic_list_len;
> > +             };
> > +     };
> > +     uint64_t regs[62];
> > +};
> > +
> > +struct adreno_reglist_list {
> > +     /** @reg: List of register **/
> > +     const u32 *regs;
> > +     /** @count: Number of registers in the list **/
> > +     u32 count;
> > +};
> > +
> >  /**
> >   * struct a6xx_info - a6xx specific information from device table
> >   *
> > @@ -31,6 +56,24 @@ struct a6xx_gpu {
> >       uint64_t sqe_iova;
> >
> >       struct msm_ringbuffer *cur_ring;
> > +     struct msm_ringbuffer *next_ring;
> > +
> > +     struct drm_gem_object *preempt_bo[MSM_GPU_MAX_RINGS];
> > +     void *preempt[MSM_GPU_MAX_RINGS];
> > +     uint64_t preempt_iova[MSM_GPU_MAX_RINGS];
> > +     uint32_t last_seqno[MSM_GPU_MAX_RINGS];
> > +
> > +     atomic_t preempt_state;
> > +     spinlock_t eval_lock;
> > +     struct timer_list preempt_timer;
> > +
> > +     unsigned int preempt_level;
> > +     bool uses_gmem;
> > +     bool skip_save_restore;
> > +
> > +     struct drm_gem_object *scratch_bo;
> > +     void *scratch_ptr;
> > +     uint64_t scratch_iova;
> >
> >       struct a6xx_gmu gmu;
> >
> > @@ -38,6 +81,10 @@ struct a6xx_gpu {
> >       uint64_t shadow_iova;
> >       uint32_t *shadow;
> >
> > +     struct drm_gem_object *pwrup_reglist_bo;
> > +     void *pwrup_reglist_ptr;
> > +     uint64_t pwrup_reglist_iova;
> > +
> >       bool has_whereami;
> >
> >       void __iomem *llc_mmio;
> > @@ -49,6 +96,108 @@ struct a6xx_gpu {
> >
> >  #define to_a6xx_gpu(x) container_of(x, struct a6xx_gpu, base)
> >
> > +#define SCRATCH_USER_CTX_IOVA(ring_id, a6xx_gpu) \
> > +     (a6xx_gpu->scratch_iova + (ring_id * sizeof(uint64_t)))
> > +
> > +/*
> > + * In order to do lockless preemption we use a simple state machine to progress
> > + * through the process.
> > + *
> > + * PREEMPT_NONE - no preemption in progress.  Next state START.
> > + * PREEMPT_START - The trigger is evaluating if preemption is possible. Next
> > + * states: TRIGGERED, NONE
> > + * PREEMPT_FINISH - An intermediate state before moving back to NONE. Next
> > + * state: NONE.
> > + * PREEMPT_TRIGGERED: A preemption has been executed on the hardware. Next
> > + * states: FAULTED, PENDING
> > + * PREEMPT_FAULTED: A preemption timed out (never completed). This will trigger
> > + * recovery.  Next state: N/A
> > + * PREEMPT_PENDING: Preemption complete interrupt fired - the callback is
> > + * checking the success of the operation. Next state: FAULTED, NONE.
> > + */
> > +
> > +enum a6xx_preempt_state {
> > +     PREEMPT_NONE = 0,
> > +     PREEMPT_START,
> > +     PREEMPT_FINISH,
> > +     PREEMPT_TRIGGERED,
> > +     PREEMPT_FAULTED,
> > +     PREEMPT_PENDING,
> > +};
> > +
> > +/*
> > + * struct a6xx_preempt_record is a shared buffer between the microcode and the
> > + * CPU to store the state for preemption. The record itself is much larger
> > + * (2112k) but most of that is used by the CP for storage.
> > + *
> > + * There is a preemption record assigned per ringbuffer. When the CPU triggers a
> > + * preemption, it fills out the record with the useful information (wptr, ring
> > + * base, etc) and the microcode uses that information to set up the CP following
> > + * the preemption.  When a ring is switched out, the CP will save the ringbuffer
> > + * state back to the record. In this way, once the records are properly set up
> > + * the CPU can quickly switch back and forth between ringbuffers by only
> > + * updating a few registers (often only the wptr).
> > + *
> > + * These are the CPU aware registers in the record:
> > + * @magic: Must always be 0xAE399D6EUL
> > + * @info: Type of the record - written 0 by the CPU, updated by the CP
> > + * @errno: preemption error record
> > + * @data: Data field in YIELD and SET_MARKER packets, Written and used by CP
> > + * @cntl: Value of RB_CNTL written by CPU, save/restored by CP
> > + * @rptr: Value of RB_RPTR written by CPU, save/restored by CP
> > + * @wptr: Value of RB_WPTR written by CPU, save/restored by CP
> > + * @_pad: Reserved/padding
> > + * @rptr_addr: Value of RB_RPTR_ADDR_LO|HI written by CPU, save/restored by CP
> > + * @rbase: Value of RB_BASE written by CPU, save/restored by CP
> > + * @counter: GPU address of the storage area for the preemption counters
> > + */
> > +struct a6xx_preempt_record {
> > +     u32 magic;
> > +     u32 info;
> > +     u32 errno;
> > +     u32 data;
> > +     u32 cntl;
> > +     u32 rptr;
> > +     u32 wptr;
> > +     u32 _pad;
> > +     u64 rptr_addr;
> > +     u64 rbase;
> > +     u64 counter;
> > +     u64 bv_rptr_addr;
> > +};
> > +
> > +#define A6XX_PREEMPT_RECORD_MAGIC 0xAE399D6EUL
> > +
> > +#define PREEMPT_RECORD_SIZE_FALLBACK(size) \
> > +     ((size) == 0 ? 4192 * SZ_1K : (size))
> > +
> > +#define PREEMPT_OFFSET_SMMU_INFO 0
> > +#define PREEMPT_OFFSET_PRIV_NON_SECURE (PREEMPT_OFFSET_SMMU_INFO + 4096)
> > +#define PREEMPT_OFFSET_PRIV_SECURE(size) \
> > +     (PREEMPT_OFFSET_PRIV_NON_SECURE + PREEMPT_RECORD_SIZE_FALLBACK(size))
> > +#define PREEMPT_SIZE(size) \
> > +     (PREEMPT_OFFSET_PRIV_SECURE(size) + PREEMPT_RECORD_SIZE_FALLBACK(size))
> > +
> > +/*
> > + * The preemption counter block is a storage area for the value of the
> > + * preemption counters that are saved immediately before context switch. We
> > + * append it on to the end of the allocation for the preemption record.
> > + */
> > +#define A6XX_PREEMPT_COUNTER_SIZE (16 * 4)
> > +
> > +#define A6XX_PREEMPT_USER_RECORD_SIZE (192 * 1024)
> > +
> > +struct a7xx_cp_smmu_info {
> > +     u32 magic;
> > +     u32 _pad4;
> > +     u64 ttbr0;
> > +     u32 asid;
> > +     u32 context_idr;
> > +     u32 context_bank;
> > +};
> > +
> > +#define GEN7_CP_SMMU_INFO_MAGIC 0x241350d5UL
> > +
> >  /*
> >   * Given a register and a count, return a value to program into
> >   * REG_CP_PROTECT_REG(n) - this will block both reads and writes for
> > @@ -106,6 +255,25 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
> >  int a6xx_gmu_wrapper_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
> >  void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu);
> >
> > +void a6xx_preempt_init(struct msm_gpu *gpu);
> > +void a6xx_preempt_hw_init(struct msm_gpu *gpu);
> > +void a6xx_preempt_trigger(struct msm_gpu *gpu);
> > +void a6xx_preempt_irq(struct msm_gpu *gpu);
> > +void a6xx_preempt_fini(struct msm_gpu *gpu);
> > +int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
> > +             struct msm_gpu_submitqueue *queue);
> > +void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
> > +             struct msm_gpu_submitqueue *queue);
> > +
> > +/* Return true if we are in a preempt state */
> > +static inline bool a6xx_in_preempt(struct a6xx_gpu *a6xx_gpu)
> > +{
> > +     int preempt_state = atomic_read(&a6xx_gpu->preempt_state);
> > +
> > +     return !(preempt_state == PREEMPT_NONE ||
> > +                     preempt_state == PREEMPT_FINISH);
> > +}
> > +
> >  void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp,
> >                      bool suspended);
> >  unsigned long a6xx_gmu_get_freq(struct msm_gpu *gpu);
> > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_preempt.c b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
> > new file mode 100644
> > index 000000000000..0d402a3bcf5a
> > --- /dev/null
> > +++ b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
> > @@ -0,0 +1,434 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/* Copyright (c) 2018, The Linux Foundation. All rights reserved. */
> > +/* Copyright (c) 2023 Collabora, Ltd. */
> > +/* Copyright (c) 2024 Valve Corporation */
> > +
> > +#include "msm_gem.h"
> > +#include "a6xx_gpu.h"
> > +#include "a6xx_gmu.xml.h"
> > +#include "msm_mmu.h"
> > +
> > +#define FENCE_STATUS_WRITEDROPPED0_MASK 0x1
> > +#define FENCE_STATUS_WRITEDROPPED1_MASK 0x2
> > +
> > +/*
> > + * Try to transition the preemption state from old to new. Return
> > + * true on success or false if the original state wasn't 'old'
> > + */
> > +static inline bool try_preempt_state(struct a6xx_gpu *a6xx_gpu,
> > +             enum a6xx_preempt_state old, enum a6xx_preempt_state new)
> > +{
> > +     enum a6xx_preempt_state cur = atomic_cmpxchg(&a6xx_gpu->preempt_state,
> > +             old, new);
> > +
> > +     return (cur == old);
> > +}
> > +
> > +/*
> > + * Force the preemption state to the specified state.  This is used in cases
> > + * where the current state is known and won't change
> > + */
> > +static inline void set_preempt_state(struct a6xx_gpu *gpu,
> > +             enum a6xx_preempt_state new)
> > +{
> > +     /*
> > +      * preempt_state may be read by other cores trying to trigger a
> > +      * preemption or in the interrupt handler so barriers are needed
> > +      * before...
> > +      */
> > +     smp_mb__before_atomic();
> > +     atomic_set(&gpu->preempt_state, new);
> > +     /* ... and after*/
> > +     smp_mb__after_atomic();
> > +}
> > +
> > +/* Write the most recent wptr for the given ring into the hardware */
> > +static inline void update_wptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > +{
> > +     unsigned long flags;
> > +     uint32_t wptr, cur_wptr;
> > +
> > +     if (!ring)
> > +             return;
> > +
> > +     spin_lock_irqsave(&ring->preempt_lock, flags);
> > +
> > +     if (ring->skip_inline_wptr) {
> > +             wptr = get_wptr(ring);
> > +
> > +             gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > +
> > +             ring->skip_inline_wptr = false;
> > +     }
> > +
> > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > +}
> > +
> > +/* Return the highest priority ringbuffer with something in it */
> > +static struct msm_ringbuffer *get_next_ring(struct msm_gpu *gpu)
> > +{
> > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > +
> > +     unsigned long flags;
> > +     int i;
> > +
> > +     for (i = 0; i < gpu->nr_rings; i++) {
> > +             bool empty;
> > +             struct msm_ringbuffer *ring = gpu->rb[i];
> > +
> > +             spin_lock_irqsave(&ring->preempt_lock, flags);
> > +             empty = (get_wptr(ring) == gpu->funcs->get_rptr(gpu, ring));
> > +             if (!empty && ring == a6xx_gpu->cur_ring)
> > +                     empty = ring->memptrs->fence == a6xx_gpu->last_seqno[i];
> > +             spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > +
> > +             if (!empty)
> > +                     return ring;
> > +     }
> > +
> > +     return NULL;
> > +}
> > +
> > +static void a6xx_preempt_timer(struct timer_list *t)
> > +{
> > +     struct a6xx_gpu *a6xx_gpu = from_timer(a6xx_gpu, t, preempt_timer);
> > +     struct msm_gpu *gpu = &a6xx_gpu->base.base;
> > +     struct drm_device *dev = gpu->dev;
> > +
> > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_FAULTED))
> > +             return;
> > +
> > +     dev_err(dev->dev, "%s: preemption timed out\n", gpu->name);
> > +     kthread_queue_work(gpu->worker, &gpu->recover_work);
> > +}
> > +
> > +void a6xx_preempt_irq(struct msm_gpu *gpu)
> > +{
> > +     uint32_t status;
> > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > +     struct drm_device *dev = gpu->dev;
> > +
> > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_PENDING))
> > +             return;
> > +
> > +     /* Delete the preemption watchdog timer */
> > +     del_timer(&a6xx_gpu->preempt_timer);
> > +
> > +     /*
> > +      * The hardware should be setting the stop bit of CP_CONTEXT_SWITCH_CNTL
> > +      * to zero before firing the interrupt, but there is a non zero chance
> > +      * of a hardware condition or a software race that could set it again
> > +      * before we have a chance to finish. If that happens, log and go for
> > +      * recovery
> > +      */
> > +     status = gpu_read(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL);
> > +     if (unlikely(status & 0x1)) {
> > +             DRM_DEV_ERROR(&gpu->pdev->dev,
> > +                                       "!!!!!!!!!!!!!!!! preemption faulted !!!!!!!!!!!!!! irq\n");
> > +             set_preempt_state(a6xx_gpu, PREEMPT_FAULTED);
> > +             dev_err(dev->dev, "%s: Preemption failed to complete\n",
> > +                     gpu->name);
> > +             kthread_queue_work(gpu->worker, &gpu->recover_work);
> > +             return;
> > +     }
> > +
> > +     a6xx_gpu->cur_ring = a6xx_gpu->next_ring;
> > +     a6xx_gpu->next_ring = NULL;
> > +
> > +     /* Make sure the write to cur_ring is posted before the change in state */
> > +     wmb();
> > +
> > +     set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
> > +
> > +     update_wptr(gpu, a6xx_gpu->cur_ring);
> > +
> > +     set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > +
> > +     /*
> > +      * Retrigger preemption to avoid a deadlock that might occur when preemption
> > +      * is skipped due to it being already in flight when requested.
> > +      */
> > +     a6xx_preempt_trigger(gpu);
> > +}
> > +
> > +void a6xx_preempt_hw_init(struct msm_gpu *gpu)
> > +{
> > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > +     int i;
> > +
> > +     /* No preemption if we only have one ring */
> > +     if (gpu->nr_rings == 1)
> > +             return;
> > +
> > +     for (i = 0; i < gpu->nr_rings; i++) {
> > +             struct a6xx_preempt_record *record_ptr =
> > +                     a6xx_gpu->preempt[i] + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > +             record_ptr->wptr = 0;
> > +             record_ptr->rptr = 0;
> > +             record_ptr->rptr_addr = shadowptr(a6xx_gpu, gpu->rb[i]);
> > +             record_ptr->info = 0;
> > +             record_ptr->data = 0;
> > +             record_ptr->rbase = gpu->rb[i]->iova;
> > +     }
> > +
> > +     /* Write a 0 to signal that we aren't switching pagetables */
> > +     gpu_write64(gpu, REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO, 0);
> > +
> > +     /* Enable the GMEM save/restore feature for preemption */
> > +     gpu_write(gpu, REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE, 0x1);
> > +
> > +     /* Reset the preemption state */
> > +     set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > +
> > +     spin_lock_init(&a6xx_gpu->eval_lock);
> > +
> > +     /* Always come up on rb 0 */
> > +     a6xx_gpu->cur_ring = gpu->rb[0];
> > +}
> > +
> > +void a6xx_preempt_trigger(struct msm_gpu *gpu)
> > +{
> > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > +     u64 preempt_offset_priv_secure;
> > +     unsigned long flags;
> > +     struct msm_ringbuffer *ring;
> > +     uint64_t user_ctx_iova;
> > +     unsigned int cntl;
> > +
> > +     if (gpu->nr_rings == 1)
> > +             return;
> > +
> > +     /*
> > +      * Lock to make sure another thread attempting preemption doesn't skip it
> > +      * while we are still evaluating the next ring. This makes sure the other
> > +      * thread does start preemption if we abort it and avoids a soft lock.
> > +      */
> > +     spin_lock_irqsave(&a6xx_gpu->eval_lock, flags);
> > +
> > +     /*
> > +      * Try to start preemption by moving from NONE to START. If
> > +      * unsuccessful, a preemption is already in flight
> > +      */
> > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_NONE, PREEMPT_START)) {
> > +             spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > +             return;
> > +     }
> > +
> > +     cntl = (((a6xx_gpu->preempt_level << 6) & 0xC0) |
> > +             ((a6xx_gpu->skip_save_restore << 9) & 0x200) |
> > +             ((a6xx_gpu->uses_gmem << 8) & 0x100) | 0x1);
> > +
> > +     /* Get the next ring to preempt to */
> > +     ring = get_next_ring(gpu);
> > +
> > +     /*
> > +      * If no ring is populated or the highest priority ring is the current
> > +      * one do nothing except to update the wptr to the latest and greatest
> > +      */
> > +     if (!ring || (a6xx_gpu->cur_ring == ring)) {
> > +             set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
> > +             update_wptr(gpu, a6xx_gpu->cur_ring);
> > +             set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > +             spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > +             return;
> > +     }
> > +
> > +     spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > +
> > +     spin_lock_irqsave(&ring->preempt_lock, flags);
> > +
> > +     struct a7xx_cp_smmu_info *smmu_info_ptr =
> > +             a6xx_gpu->preempt[ring->id] + PREEMPT_OFFSET_SMMU_INFO;
> > +     struct a6xx_preempt_record *record_ptr =
> > +             a6xx_gpu->preempt[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > +     u64 ttbr0 = ring->memptrs->ttbr0;
> > +     u32 context_idr = ring->memptrs->context_idr;
> > +
> > +     smmu_info_ptr->ttbr0 = ttbr0;
> > +     smmu_info_ptr->context_idr = context_idr;
> > +     record_ptr->wptr = get_wptr(ring);
> > +
> > +     /*
> > +      * The GPU will write the wptr we set above when we preempt. Reset
> > +      * skip_inline_wptr to make sure that we don't write WPTR to the same
> > +      * thing twice. It's still possible subsequent submissions will update
> > +      * wptr again, in which case they will set the flag to true. This has
> > +      * to be protected by the lock for setting the flag and updating wptr
> > +      * to be atomic.
> > +      */
> > +     ring->skip_inline_wptr = false;
> > +
> > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > +
> > +     gpu_write64(gpu,
> > +             REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO,
> > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_SMMU_INFO);
> > +
> > +     gpu_write64(gpu,
> > +             REG_A6XX_CP_CONTEXT_SWITCH_PRIV_NON_SECURE_RESTORE_ADDR,
> > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE);
> > +
> > +     preempt_offset_priv_secure =
> > +             PREEMPT_OFFSET_PRIV_SECURE(adreno_gpu->info->preempt_record_size);
> > +     gpu_write64(gpu,
> > +             REG_A6XX_CP_CONTEXT_SWITCH_PRIV_SECURE_RESTORE_ADDR,
> > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure);
> > +
> > +     /*
> > +      * Use the user context iova from the scratch memory that the CP may
> > +      * have written as part of the ring switch out.
> > +      */
> > +     user_ctx_iova = *((uint64_t *)a6xx_gpu->scratch_ptr + ring->id);
> > +
> > +     gpu_write64(gpu,
> > +             REG_A6XX_CP_CONTEXT_SWITCH_NON_PRIV_RESTORE_ADDR,
> > +             user_ctx_iova);
> > +
> > +     a6xx_gpu->next_ring = ring;
> > +
> > +     /* Start a timer to catch a stuck preemption */
> > +     mod_timer(&a6xx_gpu->preempt_timer, jiffies + msecs_to_jiffies(10000));
> > +
> > +     /* Set the preemption state to triggered */
> > +     set_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED);
> > +
> > +     /* Make sure any previous writes to WPTR are posted */
> > +     gpu_read(gpu, REG_A6XX_CP_RB_WPTR);
> > +
> > +     /* Make sure everything is written before hitting the button */
> > +     wmb();
> > +
> > +     /* Trigger the preemption */
> > +     gpu_write(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL, cntl);
> > +}
> > +
> > +static int preempt_init_ring(struct a6xx_gpu *a6xx_gpu,
> > +             struct msm_ringbuffer *ring)
> > +{
> > +     struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
> > +     struct msm_gpu *gpu = &adreno_gpu->base;
> > +     struct drm_gem_object *bo = NULL;
> > +     phys_addr_t ttbr;
> > +     u64 iova = 0;
> > +     void *ptr;
> > +     int asid;
> > +
> > +     ptr = msm_gem_kernel_new(gpu->dev,
> > +             PREEMPT_SIZE(adreno_gpu->info->preempt_record_size),
> > +             MSM_BO_WC | MSM_BO_MAP_PRIV, gpu->aspace, &bo, &iova);
> > +
> > +     memset(ptr, 0, PREEMPT_SIZE(adreno_gpu->info->preempt_record_size));
> > +
> > +     if (IS_ERR(ptr))
> > +             return PTR_ERR(ptr);
> > +
> > +     a6xx_gpu->preempt_bo[ring->id] = bo;
> > +     a6xx_gpu->preempt_iova[ring->id] = iova;
> > +     a6xx_gpu->preempt[ring->id] = ptr;
> > +
> > +     struct a7xx_cp_smmu_info *smmu_info_ptr = ptr + PREEMPT_OFFSET_SMMU_INFO;
> > +     struct a6xx_preempt_record *record_ptr = ptr + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > +
> > +     msm_iommu_pagetable_params(gpu->aspace->mmu, &ttbr, &asid);
> > +
> > +     smmu_info_ptr->magic = GEN7_CP_SMMU_INFO_MAGIC;
> > +     smmu_info_ptr->ttbr0 = ttbr;
> > +     smmu_info_ptr->asid = 0xdecafbad;
> > +     smmu_info_ptr->context_idr = 0;
> > +
> > +     /* Set up the defaults on the preemption record */
> > +     record_ptr->magic = A6XX_PREEMPT_RECORD_MAGIC;
> > +     record_ptr->info = 0;
> > +     record_ptr->data = 0;
> > +     record_ptr->rptr = 0;
> > +     record_ptr->wptr = 0;
> > +     record_ptr->cntl = MSM_GPU_RB_CNTL_DEFAULT;
> > +     record_ptr->rbase = ring->iova;
> > +     record_ptr->counter = 0;
> > +     record_ptr->bv_rptr_addr = rbmemptr(ring, bv_rptr);
> > +
> > +     return 0;
> > +}
> > +
> > +void a6xx_preempt_fini(struct msm_gpu *gpu)
> > +{
> > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > +     int i;
> > +
> > +     for (i = 0; i < gpu->nr_rings; i++)
> > +             msm_gem_kernel_put(a6xx_gpu->preempt_bo[i], gpu->aspace);
> > +}
> > +
> > +void a6xx_preempt_init(struct msm_gpu *gpu)
> > +{
> > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > +     int i;
> > +
> > +     /* No preemption if we only have one ring */
> > +     if (gpu->nr_rings <= 1)
> > +             return;
> > +
> > +     for (i = 0; i < gpu->nr_rings; i++) {
> > +             if (preempt_init_ring(a6xx_gpu, gpu->rb[i]))
> > +                     goto fail;
> > +     }
> > +
> > +     /* TODO: make this configurable? */
> > +     a6xx_gpu->preempt_level = 1;
> > +     a6xx_gpu->uses_gmem = 1;
> > +     a6xx_gpu->skip_save_restore = 1;
> > +
> > +     a6xx_gpu->scratch_ptr  = msm_gem_kernel_new(gpu->dev,
> > +                     gpu->nr_rings * sizeof(uint64_t), MSM_BO_WC,
> > +                     gpu->aspace, &a6xx_gpu->scratch_bo,
> > +                     &a6xx_gpu->scratch_iova);
> > +
> > +     if (IS_ERR(a6xx_gpu->scratch_ptr))
> > +             goto fail;
> > +
> > +     timer_setup(&a6xx_gpu->preempt_timer, a6xx_preempt_timer, 0);
> > +
> > +     return;
> > +fail:
> > +     /*
> > +      * On any failure our adventure is over. Clean up and
> > +      * set nr_rings to 1 to force preemption off
> > +      */
> > +     a6xx_preempt_fini(gpu);
> > +     gpu->nr_rings = 1;
> > +
> > +     return;
> > +}
> > +
> > +void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
> > +             struct msm_gpu_submitqueue *queue)
> > +{
> > +     if (!queue->bo)
> > +             return;
> > +
> > +     msm_gem_kernel_put(queue->bo, gpu->aspace);
> > +}
> > +
> > +int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
> > +             struct msm_gpu_submitqueue *queue)
> > +{
> > +     void *ptr;
> > +
> > +     /*
> > +      * Create a per submitqueue buffer for the CP to save and restore user
> > +      * specific information such as the VPC streamout data.
> > +      */
> > +     ptr = msm_gem_kernel_new(gpu->dev, A6XX_PREEMPT_USER_RECORD_SIZE,
> > +                     MSM_BO_WC, gpu->aspace, &queue->bo, &queue->bo_iova);
> > +
> > +     if (IS_ERR(ptr))
> > +             return PTR_ERR(ptr);
> > +
> > +     return 0;
> > +}
> > diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.h b/drivers/gpu/drm/msm/msm_ringbuffer.h
> > index 40791b2ade46..7dde6a312511 100644
> > --- a/drivers/gpu/drm/msm/msm_ringbuffer.h
> > +++ b/drivers/gpu/drm/msm/msm_ringbuffer.h
> > @@ -36,6 +36,7 @@ struct msm_rbmemptrs {
> >
> >       volatile struct msm_gpu_submit_stats stats[MSM_GPU_SUBMIT_STATS_COUNT];
> >       volatile u64 ttbr0;
> > +     volatile u32 context_idr;
> >  };
> >
> >  struct msm_cp_state {
> > @@ -100,6 +101,12 @@ struct msm_ringbuffer {
> >        * preemption.  Can be aquired from irq context.
> >        */
> >       spinlock_t preempt_lock;
> > +
> > +     /*
> > +      * Whether we skipped writing wptr and it needs to be updated in the
> > +      * future when the ring becomes current.
> > +      */
> > +     bool skip_inline_wptr;
> >  };
> >
> >  struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int id,
> >
> > --
> > 2.46.0
> >
> >

Akhil P Oommen Aug. 22, 2024, 7:23 p.m. UTC | #6

On Wed, Aug 21, 2024 at 04:34:15PM +0200, Antonino Maniscalco wrote:
> On 8/19/24 10:08 PM, Akhil P Oommen wrote:
> > On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
> > > This patch implements preemption feature for A6xx targets, this allows
> > > the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
> > > hardware as such supports multiple levels of preemption granularities,
> > > ranging from coarse grained(ringbuffer level) to a more fine grained
> > > such as draw-call level or a bin boundary level preemption. This patch
> > > enables the basic preemption level, with more fine grained preemption
> > > support to follow.
> > > 
> > > Signed-off-by: Sharat Masetty <[e-mail]>
> > > Signed-off-by: Antonino Maniscalco <[e-mail]>
> > > ---
> > 
> > No postamble packets which resets perfcounters? It is necessary. Also, I
> > think we should disable preemption during profiling like we disable slumber.
> > 
> > -Akhil.
> > 
> 
> You mention that we disable slumber during profiling however I wasn't able
> to find code doing that. Can you please clarify which code you are referring
> to or a mechanism through which the kernel can know when we are profiling?
> 

Please check msm_file_private_set_sysprof().

-Akhil

> Best regards,
> -- 
> Antonino Maniscalco <[e-mail]>
>

Akhil P Oommen Aug. 22, 2024, 8:05 p.m. UTC | #7

On Wed, Aug 21, 2024 at 05:02:56PM +0100, Connor Abbott wrote:
> On Mon, Aug 19, 2024 at 9:09 PM Akhil P Oommen <[e-mail]> wrote:
> >
> > On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
> > > This patch implements preemption feature for A6xx targets, this allows
> > > the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
> > > hardware as such supports multiple levels of preemption granularities,
> > > ranging from coarse grained(ringbuffer level) to a more fine grained
> > > such as draw-call level or a bin boundary level preemption. This patch
> > > enables the basic preemption level, with more fine grained preemption
> > > support to follow.
> > >
> > > Signed-off-by: Sharat Masetty <[e-mail]>
> > > Signed-off-by: Antonino Maniscalco <[e-mail]>
> > > ---
> >
> > No postamble packets which resets perfcounters? It is necessary. Also, I
> > think we should disable preemption during profiling like we disable slumber.
> >
> > -Akhil.
> 
> I don't see anything in kgsl which disables preemption during
> profiling. It disables resetting perfcounters when doing system-wide
> profiling, like freedreno, and in that case I assume preempting is
> fine because the system profiler has a complete view of everything and
> should "see" preemptions through the traces. For something like
> VK_KHR_performance_query I suppose we'd want to disable preemption
> because we disable saving/restoring perf counters, but that has to
> happen in userspace because the kernel doesn't know what userspace
> does.
> 

KGSL does some sort of arbitration of perfcounter configurations and
adds the select/enablement reg configuration as part of dynamic
power up register list which we are not doing here. Is this something
you are taking care of from userspace via preamble?

-Akhil

> Connor
> 
> >
> > >  drivers/gpu/drm/msm/Makefile              |   1 +
> > >  drivers/gpu/drm/msm/adreno/a6xx_gpu.c     | 323 +++++++++++++++++++++-
> > >  drivers/gpu/drm/msm/adreno/a6xx_gpu.h     | 168 ++++++++++++
> > >  drivers/gpu/drm/msm/adreno/a6xx_preempt.c | 434 ++++++++++++++++++++++++++++++
> > >  drivers/gpu/drm/msm/msm_ringbuffer.h      |   7 +
> > >  5 files changed, 924 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile
> > > index f5e2838c6a76..32e915109a59 100644
> > > --- a/drivers/gpu/drm/msm/Makefile
> > > +++ b/drivers/gpu/drm/msm/Makefile
> > > @@ -23,6 +23,7 @@ adreno-y := \
> > >       adreno/a6xx_gpu.o \
> > >       adreno/a6xx_gmu.o \
> > >       adreno/a6xx_hfi.o \
> > > +     adreno/a6xx_preempt.o \
> > >
> > >  adreno-$(CONFIG_DEBUG_FS) += adreno/a5xx_debugfs.o \
> > >
> > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > index 32a4faa93d7f..1a90db5759b8 100644
> > > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > @@ -16,6 +16,83 @@
> > >
> > >  #define GPU_PAS_ID 13
> > >
> > > +/* IFPC & Preemption static powerup restore list */
> > > +static const uint32_t a7xx_pwrup_reglist[] = {
> > > +     REG_A6XX_UCHE_TRAP_BASE,
> > > +     REG_A6XX_UCHE_TRAP_BASE + 1,
> > > +     REG_A6XX_UCHE_WRITE_THRU_BASE,
> > > +     REG_A6XX_UCHE_WRITE_THRU_BASE + 1,
> > > +     REG_A6XX_UCHE_GMEM_RANGE_MIN,
> > > +     REG_A6XX_UCHE_GMEM_RANGE_MIN + 1,
> > > +     REG_A6XX_UCHE_GMEM_RANGE_MAX,
> > > +     REG_A6XX_UCHE_GMEM_RANGE_MAX + 1,
> > > +     REG_A6XX_UCHE_CACHE_WAYS,
> > > +     REG_A6XX_UCHE_MODE_CNTL,
> > > +     REG_A6XX_RB_NC_MODE_CNTL,
> > > +     REG_A6XX_RB_CMP_DBG_ECO_CNTL,
> > > +     REG_A7XX_GRAS_NC_MODE_CNTL,
> > > +     REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE,
> > > +     REG_A6XX_UCHE_GBIF_GX_CONFIG,
> > > +     REG_A6XX_UCHE_CLIENT_PF,
> > > +};
> > > +
> > > +static const uint32_t a7xx_ifpc_pwrup_reglist[] = {
> > > +     REG_A6XX_TPL1_NC_MODE_CNTL,
> > > +     REG_A6XX_SP_NC_MODE_CNTL,
> > > +     REG_A6XX_CP_DBG_ECO_CNTL,
> > > +     REG_A6XX_CP_PROTECT_CNTL,
> > > +     REG_A6XX_CP_PROTECT(0),
> > > +     REG_A6XX_CP_PROTECT(1),
> > > +     REG_A6XX_CP_PROTECT(2),
> > > +     REG_A6XX_CP_PROTECT(3),
> > > +     REG_A6XX_CP_PROTECT(4),
> > > +     REG_A6XX_CP_PROTECT(5),
> > > +     REG_A6XX_CP_PROTECT(6),
> > > +     REG_A6XX_CP_PROTECT(7),
> > > +     REG_A6XX_CP_PROTECT(8),
> > > +     REG_A6XX_CP_PROTECT(9),
> > > +     REG_A6XX_CP_PROTECT(10),
> > > +     REG_A6XX_CP_PROTECT(11),
> > > +     REG_A6XX_CP_PROTECT(12),
> > > +     REG_A6XX_CP_PROTECT(13),
> > > +     REG_A6XX_CP_PROTECT(14),
> > > +     REG_A6XX_CP_PROTECT(15),
> > > +     REG_A6XX_CP_PROTECT(16),
> > > +     REG_A6XX_CP_PROTECT(17),
> > > +     REG_A6XX_CP_PROTECT(18),
> > > +     REG_A6XX_CP_PROTECT(19),
> > > +     REG_A6XX_CP_PROTECT(20),
> > > +     REG_A6XX_CP_PROTECT(21),
> > > +     REG_A6XX_CP_PROTECT(22),
> > > +     REG_A6XX_CP_PROTECT(23),
> > > +     REG_A6XX_CP_PROTECT(24),
> > > +     REG_A6XX_CP_PROTECT(25),
> > > +     REG_A6XX_CP_PROTECT(26),
> > > +     REG_A6XX_CP_PROTECT(27),
> > > +     REG_A6XX_CP_PROTECT(28),
> > > +     REG_A6XX_CP_PROTECT(29),
> > > +     REG_A6XX_CP_PROTECT(30),
> > > +     REG_A6XX_CP_PROTECT(31),
> > > +     REG_A6XX_CP_PROTECT(32),
> > > +     REG_A6XX_CP_PROTECT(33),
> > > +     REG_A6XX_CP_PROTECT(34),
> > > +     REG_A6XX_CP_PROTECT(35),
> > > +     REG_A6XX_CP_PROTECT(36),
> > > +     REG_A6XX_CP_PROTECT(37),
> > > +     REG_A6XX_CP_PROTECT(38),
> > > +     REG_A6XX_CP_PROTECT(39),
> > > +     REG_A6XX_CP_PROTECT(40),
> > > +     REG_A6XX_CP_PROTECT(41),
> > > +     REG_A6XX_CP_PROTECT(42),
> > > +     REG_A6XX_CP_PROTECT(43),
> > > +     REG_A6XX_CP_PROTECT(44),
> > > +     REG_A6XX_CP_PROTECT(45),
> > > +     REG_A6XX_CP_PROTECT(46),
> > > +     REG_A6XX_CP_PROTECT(47),
> > > +     REG_A6XX_CP_AHB_CNTL,
> > > +};
> > > +
> > > +
> > >  static inline bool _a6xx_check_idle(struct msm_gpu *gpu)
> > >  {
> > >       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > @@ -68,6 +145,8 @@ static void update_shadow_rptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > >
> > >  static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > >  {
> > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > >       uint32_t wptr;
> > >       unsigned long flags;
> > >
> > > @@ -81,12 +160,26 @@ static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > >       /* Make sure to wrap wptr if we need to */
> > >       wptr = get_wptr(ring);
> > >
> > > -     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > -
> > >       /* Make sure everything is posted before making a decision */
> > >       mb();
> > >
> > > -     gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > > +     /* Update HW if this is the current ring and we are not in preempt*/
> > > +     if (!a6xx_in_preempt(a6xx_gpu)) {
> > > +             /*
> > > +              * Order the reads of the preempt state and cur_ring. This
> > > +              * matches the barrier after writing cur_ring.
> > > +              */
> > > +             rmb();
> > > +
> > > +             if (a6xx_gpu->cur_ring == ring)
> > > +                     gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > > +             else
> > > +                     ring->skip_inline_wptr = true;
> > > +     } else {
> > > +             ring->skip_inline_wptr = true;
> > > +     }
> > > +
> > > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > >  }
> > >
> > >  static void get_stats_counter(struct msm_ringbuffer *ring, u32 counter,
> > > @@ -138,12 +231,14 @@ static void a6xx_set_pagetable(struct a6xx_gpu *a6xx_gpu,
> > >
> > >       /*
> > >        * Write the new TTBR0 to the memstore. This is good for debugging.
> > > +      * Needed for preemption
> > >        */
> > > -     OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > > +     OUT_PKT7(ring, CP_MEM_WRITE, 5);
> > >       OUT_RING(ring, CP_MEM_WRITE_0_ADDR_LO(lower_32_bits(memptr)));
> > >       OUT_RING(ring, CP_MEM_WRITE_1_ADDR_HI(upper_32_bits(memptr)));
> > >       OUT_RING(ring, lower_32_bits(ttbr));
> > > -     OUT_RING(ring, (asid << 16) | upper_32_bits(ttbr));
> > > +     OUT_RING(ring, upper_32_bits(ttbr));
> > > +     OUT_RING(ring, ctx->seqno);
> > >
> > >       /*
> > >        * Sync both threads after switching pagetables and enable BR only
> > > @@ -268,12 +363,55 @@ static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > >       a6xx_flush(gpu, ring);
> > >  }
> > >
> > > +static void a6xx_emit_set_pseudo_reg(struct msm_ringbuffer *ring,
> > > +             struct a6xx_gpu *a6xx_gpu, struct msm_gpu_submitqueue *queue)
> > > +{
> > > +     u64 preempt_offset_priv_secure;
> > > +
> > > +     OUT_PKT7(ring, CP_SET_PSEUDO_REG, 15);
> > > +
> > > +     OUT_RING(ring, SMMU_INFO);
> > > +     /* don't save SMMU, we write the record from the kernel instead */
> > > +     OUT_RING(ring, 0);
> > > +     OUT_RING(ring, 0);
> > > +
> > > +     /* privileged and non secure buffer save */
> > > +     OUT_RING(ring, NON_SECURE_SAVE_ADDR);
> > > +     OUT_RING(ring, lower_32_bits(
> > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE));
> > > +     OUT_RING(ring, upper_32_bits(
> > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE));
> > > +     OUT_RING(ring, SECURE_SAVE_ADDR);
> > > +     preempt_offset_priv_secure =
> > > +             PREEMPT_OFFSET_PRIV_SECURE(a6xx_gpu->base.info->preempt_record_size);
> > > +     OUT_RING(ring, lower_32_bits(
> > > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure));
> > > +     OUT_RING(ring, upper_32_bits(
> > > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure));
> > > +
> > > +     /* user context buffer save */
> > > +     OUT_RING(ring, NON_PRIV_SAVE_ADDR);
> > > +     if (queue) {
> > > +             OUT_RING(ring, lower_32_bits(queue->bo_iova));
> > > +             OUT_RING(ring, upper_32_bits(queue->bo_iova));
> > > +     } else {
> > > +             OUT_RING(ring, 0);
> > > +             OUT_RING(ring, 0);
> > > +     }
> > > +
> > > +     OUT_RING(ring, COUNTER);
> > > +     /* seems OK to set to 0 to disable it */
> > > +     OUT_RING(ring, 0);
> > > +     OUT_RING(ring, 0);
> > > +}
> > > +
> > >  static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > >  {
> > >       unsigned int index = submit->seqno % MSM_GPU_SUBMIT_STATS_COUNT;
> > >       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > >       struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > >       struct msm_ringbuffer *ring = submit->ring;
> > > +     uint64_t scratch_dest = SCRATCH_USER_CTX_IOVA(ring->id, a6xx_gpu);
> > >       unsigned int i, ibs = 0;
> > >
> > >       /*
> > > @@ -283,6 +421,25 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > >       OUT_PKT7(ring, CP_THREAD_CONTROL, 1);
> > >       OUT_RING(ring, CP_THREAD_CONTROL_0_SYNC_THREADS | CP_SET_THREAD_BR);
> > >
> > > +     /*
> > > +      * If preemption is enabled, then set the pseudo register for the save
> > > +      * sequence
> > > +      */
> > > +     if (gpu->nr_rings > 1) {
> > > +             a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, submit->queue);
> > > +
> > > +             /*
> > > +              * Ask CP to save the user context buffer's iova address to a
> > > +              * scratch memory region, this is needed if the CP preempts
> > > +              * this ring in between this submit's IB list.
> > > +              */
> > > +             OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > > +             OUT_RING(ring, lower_32_bits(scratch_dest));
> > > +             OUT_RING(ring, upper_32_bits(scratch_dest));
> > > +             OUT_RING(ring, lower_32_bits(submit->queue->bo_iova));
> > > +             OUT_RING(ring, upper_32_bits(submit->queue->bo_iova));
> > > +     }
> > > +
> > >       a6xx_set_pagetable(a6xx_gpu, ring, submit->queue->ctx);
> > >
> > >       get_stats_counter(ring, REG_A7XX_RBBM_PERFCTR_CP(0),
> > > @@ -376,6 +533,8 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > >       OUT_RING(ring, upper_32_bits(rbmemptr(ring, bv_fence)));
> > >       OUT_RING(ring, submit->seqno);
> > >
> > > +     a6xx_gpu->last_seqno[ring->id] = submit->seqno;
> > > +
> > >       /* write the ringbuffer timestamp */
> > >       OUT_PKT7(ring, CP_EVENT_WRITE, 4);
> > >       OUT_RING(ring, CACHE_CLEAN | CP_EVENT_WRITE_0_IRQ | BIT(27));
> > > @@ -389,10 +548,42 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > >       OUT_PKT7(ring, CP_SET_MARKER, 1);
> > >       OUT_RING(ring, 0x100); /* IFPC enable */
> > >
> > > +     /* If preemption is enabled */
> > > +     if (gpu->nr_rings > 1) {
> > > +             /*
> > > +              * Reset the scratch region as we are done with the
> > > +              * IB list of this submission
> > > +              */
> > > +             OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > > +             OUT_RING(ring, lower_32_bits(scratch_dest));
> > > +             OUT_RING(ring, upper_32_bits(scratch_dest));
> > > +             OUT_RING(ring, 0x00);
> > > +             OUT_RING(ring, 0x00);
> > > +
> > > +             /* Yield the floor on command completion */
> > > +             OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
> > > +
> > > +             /*
> > > +              * If dword[2:1] are non zero, they specify an address for
> > > +              * the CP to write the value of dword[3] to on preemption
> > > +              * complete. Write 0 to skip the write
> > > +              */
> > > +             OUT_RING(ring, 0x00);
> > > +             OUT_RING(ring, 0x00);
> > > +             /* Data value - not used if the address above is 0 */
> > > +             OUT_RING(ring, 0x01);
> > > +             /* generate interrupt on preemption completion */
> > > +             OUT_RING(ring, 0x00);
> > > +     }
> > > +
> > > +
> > >       trace_msm_gpu_submit_flush(submit,
> > >               gpu_read64(gpu, REG_A6XX_CP_ALWAYS_ON_COUNTER));
> > >
> > >       a6xx_flush(gpu, ring);
> > > +
> > > +     /* Check to see if we need to start preemption */
> > > +     a6xx_preempt_trigger(gpu);
> > >  }
> > >
> > >  static void a6xx_set_hwcg(struct msm_gpu *gpu, bool state)
> > > @@ -588,6 +779,89 @@ static void a6xx_set_ubwc_config(struct msm_gpu *gpu)
> > >                 adreno_gpu->ubwc_config.min_acc_len << 23 | hbb_lo << 21);
> > >  }
> > >
> > > +static void a7xx_patch_pwrup_reglist(struct msm_gpu *gpu)
> > > +{
> > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > +     struct adreno_reglist_list reglist[2];
> > > +     void *ptr = a6xx_gpu->pwrup_reglist_ptr;
> > > +     struct cpu_gpu_lock *lock = ptr;
> > > +     u32 *dest = (u32 *)&lock->regs[0];
> > > +     int i, j;
> > > +
> > > +     lock->gpu_req = lock->cpu_req = lock->turn = 0;
> > > +     lock->ifpc_list_len = ARRAY_SIZE(a7xx_ifpc_pwrup_reglist);
> > > +     lock->preemption_list_len = ARRAY_SIZE(a7xx_pwrup_reglist);
> > > +
> > > +     /* Static IFPC-only registers */
> > > +     reglist[0].regs = a7xx_ifpc_pwrup_reglist;
> > > +     reglist[0].count = ARRAY_SIZE(a7xx_ifpc_pwrup_reglist);
> > > +     lock->ifpc_list_len = reglist[0].count;
> > > +
> > > +     /* Static IFPC + preemption registers */
> > > +     reglist[1].regs = a7xx_pwrup_reglist;
> > > +     reglist[1].count = ARRAY_SIZE(a7xx_pwrup_reglist);
> > > +     lock->preemption_list_len = reglist[1].count;
> > > +
> > > +     /*
> > > +      * For each entry in each of the lists, write the offset and the current
> > > +      * register value into the GPU buffer
> > > +      */
> > > +     for (i = 0; i < 2; i++) {
> > > +             const u32 *r = reglist[i].regs;
> > > +
> > > +             for (j = 0; j < reglist[i].count; j++) {
> > > +                     *dest++ = r[j];
> > > +                     *dest++ = gpu_read(gpu, r[j]);
> > > +             }
> > > +     }
> > > +
> > > +     /*
> > > +      * The overall register list is composed of
> > > +      * 1. Static IFPC-only registers
> > > +      * 2. Static IFPC + preemption registers
> > > +      * 3. Dynamic IFPC + preemption registers (ex: perfcounter selects)
> > > +      *
> > > +      * The first two lists are static. Size of these lists are stored as
> > > +      * number of pairs in ifpc_list_len and preemption_list_len
> > > +      * respectively. With concurrent binning, Some of the perfcounter
> > > +      * registers being virtualized, CP needs to know the pipe id to program
> > > +      * the aperture inorder to restore the same. Thus, third list is a
> > > +      * dynamic list with triplets as
> > > +      * (<aperture, shifted 12 bits> <address> <data>), and the length is
> > > +      * stored as number for triplets in dynamic_list_len.
> > > +      */
> > > +     lock->dynamic_list_len = 0;
> > > +}
> > > +
> > > +static int a7xx_preempt_start(struct msm_gpu *gpu)
> > > +{
> > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > +     struct msm_ringbuffer *ring = gpu->rb[0];
> > > +
> > > +     if (gpu->nr_rings <= 1)
> > > +             return 0;
> > > +
> > > +     /* Turn CP protection off */
> > > +     OUT_PKT7(ring, CP_SET_PROTECTED_MODE, 1);
> > > +     OUT_RING(ring, 0);
> > > +
> > > +     a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, NULL);
> > > +
> > > +     /* Yield the floor on command completion */
> > > +     OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
> > > +     OUT_RING(ring, 0x00);
> > > +     OUT_RING(ring, 0x00);
> > > +     OUT_RING(ring, 0x01);
> > > +     /* Generate interrupt on preemption completion */
> > > +     OUT_RING(ring, 0x00);
> > > +
> > > +     a6xx_flush(gpu, ring);
> > > +
> > > +     return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
> > > +}
> > > +
> > >  static int a6xx_cp_init(struct msm_gpu *gpu)
> > >  {
> > >       struct msm_ringbuffer *ring = gpu->rb[0];
> > > @@ -619,6 +893,8 @@ static int a6xx_cp_init(struct msm_gpu *gpu)
> > >
> > >  static int a7xx_cp_init(struct msm_gpu *gpu)
> > >  {
> > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > >       struct msm_ringbuffer *ring = gpu->rb[0];
> > >       u32 mask;
> > >
> > > @@ -626,6 +902,8 @@ static int a7xx_cp_init(struct msm_gpu *gpu)
> > >       OUT_PKT7(ring, CP_THREAD_CONTROL, 1);
> > >       OUT_RING(ring, BIT(27));
> > >
> > > +     a7xx_patch_pwrup_reglist(gpu);
> > > +
> > >       OUT_PKT7(ring, CP_ME_INIT, 7);
> > >
> > >       /* Use multiple HW contexts */
> > > @@ -656,11 +934,11 @@ static int a7xx_cp_init(struct msm_gpu *gpu)
> > >
> > >       /* *Don't* send a power up reg list for concurrent binning (TODO) */
> > >       /* Lo address */
> > > -     OUT_RING(ring, 0x00000000);
> > > +     OUT_RING(ring, lower_32_bits(a6xx_gpu->pwrup_reglist_iova));
> > >       /* Hi address */
> > > -     OUT_RING(ring, 0x00000000);
> > > +     OUT_RING(ring, upper_32_bits(a6xx_gpu->pwrup_reglist_iova));
> > >       /* BIT(31) set => read the regs from the list */
> > > -     OUT_RING(ring, 0x00000000);
> > > +     OUT_RING(ring, BIT(31));
> > >
> > >       a6xx_flush(gpu, ring);
> > >       return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
> > > @@ -784,6 +1062,16 @@ static int a6xx_ucode_load(struct msm_gpu *gpu)
> > >               msm_gem_object_set_name(a6xx_gpu->shadow_bo, "shadow");
> > >       }
> > >
> > > +     a6xx_gpu->pwrup_reglist_ptr = msm_gem_kernel_new(gpu->dev, PAGE_SIZE,
> > > +                                                      MSM_BO_WC  | MSM_BO_MAP_PRIV,
> > > +                                                      gpu->aspace, &a6xx_gpu->pwrup_reglist_bo,
> > > +                                                      &a6xx_gpu->pwrup_reglist_iova);
> > > +
> > > +     if (IS_ERR(a6xx_gpu->pwrup_reglist_ptr))
> > > +             return PTR_ERR(a6xx_gpu->pwrup_reglist_ptr);
> > > +
> > > +     msm_gem_object_set_name(a6xx_gpu->pwrup_reglist_bo, "pwrup_reglist");
> > > +
> > >       return 0;
> > >  }
> > >
> > > @@ -1127,6 +1415,8 @@ static int hw_init(struct msm_gpu *gpu)
> > >       if (a6xx_gpu->shadow_bo) {
> > >               gpu_write64(gpu, REG_A6XX_CP_RB_RPTR_ADDR,
> > >                       shadowptr(a6xx_gpu, gpu->rb[0]));
> > > +             for (unsigned int i = 0; i < gpu->nr_rings; i++)
> > > +                     a6xx_gpu->shadow[i] = 0;
> > >       }
> > >
> > >       /* ..which means "always" on A7xx, also for BV shadow */
> > > @@ -1135,6 +1425,8 @@ static int hw_init(struct msm_gpu *gpu)
> > >                           rbmemptr(gpu->rb[0], bv_rptr));
> > >       }
> > >
> > > +     a6xx_preempt_hw_init(gpu);
> > > +
> > >       /* Always come up on rb 0 */
> > >       a6xx_gpu->cur_ring = gpu->rb[0];
> > >
> > > @@ -1180,6 +1472,10 @@ static int hw_init(struct msm_gpu *gpu)
> > >  out:
> > >       if (adreno_has_gmu_wrapper(adreno_gpu))
> > >               return ret;
> > > +
> > > +     /* Last step - yield the ringbuffer */
> > > +     a7xx_preempt_start(gpu);
> > > +
> > >       /*
> > >        * Tell the GMU that we are done touching the GPU and it can start power
> > >        * management
> > > @@ -1557,8 +1853,13 @@ static irqreturn_t a6xx_irq(struct msm_gpu *gpu)
> > >       if (status & A6XX_RBBM_INT_0_MASK_SWFUSEVIOLATION)
> > >               a7xx_sw_fuse_violation_irq(gpu);
> > >
> > > -     if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS)
> > > +     if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS) {
> > >               msm_gpu_retire(gpu);
> > > +             a6xx_preempt_trigger(gpu);
> > > +     }
> > > +
> > > +     if (status & A6XX_RBBM_INT_0_MASK_CP_SW)
> > > +             a6xx_preempt_irq(gpu);
> > >
> > >       return IRQ_HANDLED;
> > >  }
> > > @@ -2165,6 +2466,8 @@ static const struct adreno_gpu_funcs funcs = {
> > >               .active_ring = a6xx_active_ring,
> > >               .irq = a6xx_irq,
> > >               .destroy = a6xx_destroy,
> > > +             .submitqueue_setup = a6xx_preempt_submitqueue_setup,
> > > +             .submitqueue_close = a6xx_preempt_submitqueue_close,
> > >  #if defined(CONFIG_DRM_MSM_GPU_STATE)
> > >               .show = a6xx_show,
> > >  #endif
> > > @@ -2331,6 +2634,8 @@ struct msm_gpu *a6xx_gpu_init(struct drm_device *dev)
> > >                               a6xx_fault_handler);
> > >
> > >       a6xx_calc_ubwc_config(adreno_gpu);
> > > +     /* Set up the preemption specific bits and pieces for each ringbuffer */
> > > +     a6xx_preempt_init(gpu);
> > >
> > >       return gpu;
> > >  }
> > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > > index e3e5c53ae8af..652e49f01428 100644
> > > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > > @@ -12,6 +12,31 @@
> > >
> > >  extern bool hang_debug;
> > >
> > > +struct cpu_gpu_lock {
> > > +     uint32_t gpu_req;
> > > +     uint32_t cpu_req;
> > > +     uint32_t turn;
> > > +     union {
> > > +             struct {
> > > +                     uint16_t list_length;
> > > +                     uint16_t list_offset;
> > > +             };
> > > +             struct {
> > > +                     uint8_t ifpc_list_len;
> > > +                     uint8_t preemption_list_len;
> > > +                     uint16_t dynamic_list_len;
> > > +             };
> > > +     };
> > > +     uint64_t regs[62];
> > > +};
> > > +
> > > +struct adreno_reglist_list {
> > > +     /** @reg: List of register **/
> > > +     const u32 *regs;
> > > +     /** @count: Number of registers in the list **/
> > > +     u32 count;
> > > +};
> > > +
> > >  /**
> > >   * struct a6xx_info - a6xx specific information from device table
> > >   *
> > > @@ -31,6 +56,24 @@ struct a6xx_gpu {
> > >       uint64_t sqe_iova;
> > >
> > >       struct msm_ringbuffer *cur_ring;
> > > +     struct msm_ringbuffer *next_ring;
> > > +
> > > +     struct drm_gem_object *preempt_bo[MSM_GPU_MAX_RINGS];
> > > +     void *preempt[MSM_GPU_MAX_RINGS];
> > > +     uint64_t preempt_iova[MSM_GPU_MAX_RINGS];
> > > +     uint32_t last_seqno[MSM_GPU_MAX_RINGS];
> > > +
> > > +     atomic_t preempt_state;
> > > +     spinlock_t eval_lock;
> > > +     struct timer_list preempt_timer;
> > > +
> > > +     unsigned int preempt_level;
> > > +     bool uses_gmem;
> > > +     bool skip_save_restore;
> > > +
> > > +     struct drm_gem_object *scratch_bo;
> > > +     void *scratch_ptr;
> > > +     uint64_t scratch_iova;
> > >
> > >       struct a6xx_gmu gmu;
> > >
> > > @@ -38,6 +81,10 @@ struct a6xx_gpu {
> > >       uint64_t shadow_iova;
> > >       uint32_t *shadow;
> > >
> > > +     struct drm_gem_object *pwrup_reglist_bo;
> > > +     void *pwrup_reglist_ptr;
> > > +     uint64_t pwrup_reglist_iova;
> > > +
> > >       bool has_whereami;
> > >
> > >       void __iomem *llc_mmio;
> > > @@ -49,6 +96,108 @@ struct a6xx_gpu {
> > >
> > >  #define to_a6xx_gpu(x) container_of(x, struct a6xx_gpu, base)
> > >
> > > +#define SCRATCH_USER_CTX_IOVA(ring_id, a6xx_gpu) \
> > > +     (a6xx_gpu->scratch_iova + (ring_id * sizeof(uint64_t)))
> > > +
> > > +/*
> > > + * In order to do lockless preemption we use a simple state machine to progress
> > > + * through the process.
> > > + *
> > > + * PREEMPT_NONE - no preemption in progress.  Next state START.
> > > + * PREEMPT_START - The trigger is evaluating if preemption is possible. Next
> > > + * states: TRIGGERED, NONE
> > > + * PREEMPT_FINISH - An intermediate state before moving back to NONE. Next
> > > + * state: NONE.
> > > + * PREEMPT_TRIGGERED: A preemption has been executed on the hardware. Next
> > > + * states: FAULTED, PENDING
> > > + * PREEMPT_FAULTED: A preemption timed out (never completed). This will trigger
> > > + * recovery.  Next state: N/A
> > > + * PREEMPT_PENDING: Preemption complete interrupt fired - the callback is
> > > + * checking the success of the operation. Next state: FAULTED, NONE.
> > > + */
> > > +
> > > +enum a6xx_preempt_state {
> > > +     PREEMPT_NONE = 0,
> > > +     PREEMPT_START,
> > > +     PREEMPT_FINISH,
> > > +     PREEMPT_TRIGGERED,
> > > +     PREEMPT_FAULTED,
> > > +     PREEMPT_PENDING,
> > > +};
> > > +
> > > +/*
> > > + * struct a6xx_preempt_record is a shared buffer between the microcode and the
> > > + * CPU to store the state for preemption. The record itself is much larger
> > > + * (2112k) but most of that is used by the CP for storage.
> > > + *
> > > + * There is a preemption record assigned per ringbuffer. When the CPU triggers a
> > > + * preemption, it fills out the record with the useful information (wptr, ring
> > > + * base, etc) and the microcode uses that information to set up the CP following
> > > + * the preemption.  When a ring is switched out, the CP will save the ringbuffer
> > > + * state back to the record. In this way, once the records are properly set up
> > > + * the CPU can quickly switch back and forth between ringbuffers by only
> > > + * updating a few registers (often only the wptr).
> > > + *
> > > + * These are the CPU aware registers in the record:
> > > + * @magic: Must always be 0xAE399D6EUL
> > > + * @info: Type of the record - written 0 by the CPU, updated by the CP
> > > + * @errno: preemption error record
> > > + * @data: Data field in YIELD and SET_MARKER packets, Written and used by CP
> > > + * @cntl: Value of RB_CNTL written by CPU, save/restored by CP
> > > + * @rptr: Value of RB_RPTR written by CPU, save/restored by CP
> > > + * @wptr: Value of RB_WPTR written by CPU, save/restored by CP
> > > + * @_pad: Reserved/padding
> > > + * @rptr_addr: Value of RB_RPTR_ADDR_LO|HI written by CPU, save/restored by CP
> > > + * @rbase: Value of RB_BASE written by CPU, save/restored by CP
> > > + * @counter: GPU address of the storage area for the preemption counters
> > > + */
> > > +struct a6xx_preempt_record {
> > > +     u32 magic;
> > > +     u32 info;
> > > +     u32 errno;
> > > +     u32 data;
> > > +     u32 cntl;
> > > +     u32 rptr;
> > > +     u32 wptr;
> > > +     u32 _pad;
> > > +     u64 rptr_addr;
> > > +     u64 rbase;
> > > +     u64 counter;
> > > +     u64 bv_rptr_addr;
> > > +};
> > > +
> > > +#define A6XX_PREEMPT_RECORD_MAGIC 0xAE399D6EUL
> > > +
> > > +#define PREEMPT_RECORD_SIZE_FALLBACK(size) \
> > > +     ((size) == 0 ? 4192 * SZ_1K : (size))
> > > +
> > > +#define PREEMPT_OFFSET_SMMU_INFO 0
> > > +#define PREEMPT_OFFSET_PRIV_NON_SECURE (PREEMPT_OFFSET_SMMU_INFO + 4096)
> > > +#define PREEMPT_OFFSET_PRIV_SECURE(size) \
> > > +     (PREEMPT_OFFSET_PRIV_NON_SECURE + PREEMPT_RECORD_SIZE_FALLBACK(size))
> > > +#define PREEMPT_SIZE(size) \
> > > +     (PREEMPT_OFFSET_PRIV_SECURE(size) + PREEMPT_RECORD_SIZE_FALLBACK(size))
> > > +
> > > +/*
> > > + * The preemption counter block is a storage area for the value of the
> > > + * preemption counters that are saved immediately before context switch. We
> > > + * append it on to the end of the allocation for the preemption record.
> > > + */
> > > +#define A6XX_PREEMPT_COUNTER_SIZE (16 * 4)
> > > +
> > > +#define A6XX_PREEMPT_USER_RECORD_SIZE (192 * 1024)
> > > +
> > > +struct a7xx_cp_smmu_info {
> > > +     u32 magic;
> > > +     u32 _pad4;
> > > +     u64 ttbr0;
> > > +     u32 asid;
> > > +     u32 context_idr;
> > > +     u32 context_bank;
> > > +};
> > > +
> > > +#define GEN7_CP_SMMU_INFO_MAGIC 0x241350d5UL
> > > +
> > >  /*
> > >   * Given a register and a count, return a value to program into
> > >   * REG_CP_PROTECT_REG(n) - this will block both reads and writes for
> > > @@ -106,6 +255,25 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
> > >  int a6xx_gmu_wrapper_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
> > >  void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu);
> > >
> > > +void a6xx_preempt_init(struct msm_gpu *gpu);
> > > +void a6xx_preempt_hw_init(struct msm_gpu *gpu);
> > > +void a6xx_preempt_trigger(struct msm_gpu *gpu);
> > > +void a6xx_preempt_irq(struct msm_gpu *gpu);
> > > +void a6xx_preempt_fini(struct msm_gpu *gpu);
> > > +int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
> > > +             struct msm_gpu_submitqueue *queue);
> > > +void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
> > > +             struct msm_gpu_submitqueue *queue);
> > > +
> > > +/* Return true if we are in a preempt state */
> > > +static inline bool a6xx_in_preempt(struct a6xx_gpu *a6xx_gpu)
> > > +{
> > > +     int preempt_state = atomic_read(&a6xx_gpu->preempt_state);
> > > +
> > > +     return !(preempt_state == PREEMPT_NONE ||
> > > +                     preempt_state == PREEMPT_FINISH);
> > > +}
> > > +
> > >  void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp,
> > >                      bool suspended);
> > >  unsigned long a6xx_gmu_get_freq(struct msm_gpu *gpu);
> > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_preempt.c b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
> > > new file mode 100644
> > > index 000000000000..0d402a3bcf5a
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
> > > @@ -0,0 +1,434 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/* Copyright (c) 2018, The Linux Foundation. All rights reserved. */
> > > +/* Copyright (c) 2023 Collabora, Ltd. */
> > > +/* Copyright (c) 2024 Valve Corporation */
> > > +
> > > +#include "msm_gem.h"
> > > +#include "a6xx_gpu.h"
> > > +#include "a6xx_gmu.xml.h"
> > > +#include "msm_mmu.h"
> > > +
> > > +#define FENCE_STATUS_WRITEDROPPED0_MASK 0x1
> > > +#define FENCE_STATUS_WRITEDROPPED1_MASK 0x2
> > > +
> > > +/*
> > > + * Try to transition the preemption state from old to new. Return
> > > + * true on success or false if the original state wasn't 'old'
> > > + */
> > > +static inline bool try_preempt_state(struct a6xx_gpu *a6xx_gpu,
> > > +             enum a6xx_preempt_state old, enum a6xx_preempt_state new)
> > > +{
> > > +     enum a6xx_preempt_state cur = atomic_cmpxchg(&a6xx_gpu->preempt_state,
> > > +             old, new);
> > > +
> > > +     return (cur == old);
> > > +}
> > > +
> > > +/*
> > > + * Force the preemption state to the specified state.  This is used in cases
> > > + * where the current state is known and won't change
> > > + */
> > > +static inline void set_preempt_state(struct a6xx_gpu *gpu,
> > > +             enum a6xx_preempt_state new)
> > > +{
> > > +     /*
> > > +      * preempt_state may be read by other cores trying to trigger a
> > > +      * preemption or in the interrupt handler so barriers are needed
> > > +      * before...
> > > +      */
> > > +     smp_mb__before_atomic();
> > > +     atomic_set(&gpu->preempt_state, new);
> > > +     /* ... and after*/
> > > +     smp_mb__after_atomic();
> > > +}
> > > +
> > > +/* Write the most recent wptr for the given ring into the hardware */
> > > +static inline void update_wptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > > +{
> > > +     unsigned long flags;
> > > +     uint32_t wptr, cur_wptr;
> > > +
> > > +     if (!ring)
> > > +             return;
> > > +
> > > +     spin_lock_irqsave(&ring->preempt_lock, flags);
> > > +
> > > +     if (ring->skip_inline_wptr) {
> > > +             wptr = get_wptr(ring);
> > > +
> > > +             gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > > +
> > > +             ring->skip_inline_wptr = false;
> > > +     }
> > > +
> > > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > +}
> > > +
> > > +/* Return the highest priority ringbuffer with something in it */
> > > +static struct msm_ringbuffer *get_next_ring(struct msm_gpu *gpu)
> > > +{
> > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > +
> > > +     unsigned long flags;
> > > +     int i;
> > > +
> > > +     for (i = 0; i < gpu->nr_rings; i++) {
> > > +             bool empty;
> > > +             struct msm_ringbuffer *ring = gpu->rb[i];
> > > +
> > > +             spin_lock_irqsave(&ring->preempt_lock, flags);
> > > +             empty = (get_wptr(ring) == gpu->funcs->get_rptr(gpu, ring));
> > > +             if (!empty && ring == a6xx_gpu->cur_ring)
> > > +                     empty = ring->memptrs->fence == a6xx_gpu->last_seqno[i];
> > > +             spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > +
> > > +             if (!empty)
> > > +                     return ring;
> > > +     }
> > > +
> > > +     return NULL;
> > > +}
> > > +
> > > +static void a6xx_preempt_timer(struct timer_list *t)
> > > +{
> > > +     struct a6xx_gpu *a6xx_gpu = from_timer(a6xx_gpu, t, preempt_timer);
> > > +     struct msm_gpu *gpu = &a6xx_gpu->base.base;
> > > +     struct drm_device *dev = gpu->dev;
> > > +
> > > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_FAULTED))
> > > +             return;
> > > +
> > > +     dev_err(dev->dev, "%s: preemption timed out\n", gpu->name);
> > > +     kthread_queue_work(gpu->worker, &gpu->recover_work);
> > > +}
> > > +
> > > +void a6xx_preempt_irq(struct msm_gpu *gpu)
> > > +{
> > > +     uint32_t status;
> > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > +     struct drm_device *dev = gpu->dev;
> > > +
> > > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_PENDING))
> > > +             return;
> > > +
> > > +     /* Delete the preemption watchdog timer */
> > > +     del_timer(&a6xx_gpu->preempt_timer);
> > > +
> > > +     /*
> > > +      * The hardware should be setting the stop bit of CP_CONTEXT_SWITCH_CNTL
> > > +      * to zero before firing the interrupt, but there is a non zero chance
> > > +      * of a hardware condition or a software race that could set it again
> > > +      * before we have a chance to finish. If that happens, log and go for
> > > +      * recovery
> > > +      */
> > > +     status = gpu_read(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL);
> > > +     if (unlikely(status & 0x1)) {
> > > +             DRM_DEV_ERROR(&gpu->pdev->dev,
> > > +                                       "!!!!!!!!!!!!!!!! preemption faulted !!!!!!!!!!!!!! irq\n");
> > > +             set_preempt_state(a6xx_gpu, PREEMPT_FAULTED);
> > > +             dev_err(dev->dev, "%s: Preemption failed to complete\n",
> > > +                     gpu->name);
> > > +             kthread_queue_work(gpu->worker, &gpu->recover_work);
> > > +             return;
> > > +     }
> > > +
> > > +     a6xx_gpu->cur_ring = a6xx_gpu->next_ring;
> > > +     a6xx_gpu->next_ring = NULL;
> > > +
> > > +     /* Make sure the write to cur_ring is posted before the change in state */
> > > +     wmb();
> > > +
> > > +     set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
> > > +
> > > +     update_wptr(gpu, a6xx_gpu->cur_ring);
> > > +
> > > +     set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > > +
> > > +     /*
> > > +      * Retrigger preemption to avoid a deadlock that might occur when preemption
> > > +      * is skipped due to it being already in flight when requested.
> > > +      */
> > > +     a6xx_preempt_trigger(gpu);
> > > +}
> > > +
> > > +void a6xx_preempt_hw_init(struct msm_gpu *gpu)
> > > +{
> > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > +     int i;
> > > +
> > > +     /* No preemption if we only have one ring */
> > > +     if (gpu->nr_rings == 1)
> > > +             return;
> > > +
> > > +     for (i = 0; i < gpu->nr_rings; i++) {
> > > +             struct a6xx_preempt_record *record_ptr =
> > > +                     a6xx_gpu->preempt[i] + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > > +             record_ptr->wptr = 0;
> > > +             record_ptr->rptr = 0;
> > > +             record_ptr->rptr_addr = shadowptr(a6xx_gpu, gpu->rb[i]);
> > > +             record_ptr->info = 0;
> > > +             record_ptr->data = 0;
> > > +             record_ptr->rbase = gpu->rb[i]->iova;
> > > +     }
> > > +
> > > +     /* Write a 0 to signal that we aren't switching pagetables */
> > > +     gpu_write64(gpu, REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO, 0);
> > > +
> > > +     /* Enable the GMEM save/restore feature for preemption */
> > > +     gpu_write(gpu, REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE, 0x1);
> > > +
> > > +     /* Reset the preemption state */
> > > +     set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > > +
> > > +     spin_lock_init(&a6xx_gpu->eval_lock);
> > > +
> > > +     /* Always come up on rb 0 */
> > > +     a6xx_gpu->cur_ring = gpu->rb[0];
> > > +}
> > > +
> > > +void a6xx_preempt_trigger(struct msm_gpu *gpu)
> > > +{
> > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > +     u64 preempt_offset_priv_secure;
> > > +     unsigned long flags;
> > > +     struct msm_ringbuffer *ring;
> > > +     uint64_t user_ctx_iova;
> > > +     unsigned int cntl;
> > > +
> > > +     if (gpu->nr_rings == 1)
> > > +             return;
> > > +
> > > +     /*
> > > +      * Lock to make sure another thread attempting preemption doesn't skip it
> > > +      * while we are still evaluating the next ring. This makes sure the other
> > > +      * thread does start preemption if we abort it and avoids a soft lock.
> > > +      */
> > > +     spin_lock_irqsave(&a6xx_gpu->eval_lock, flags);
> > > +
> > > +     /*
> > > +      * Try to start preemption by moving from NONE to START. If
> > > +      * unsuccessful, a preemption is already in flight
> > > +      */
> > > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_NONE, PREEMPT_START)) {
> > > +             spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > > +             return;
> > > +     }
> > > +
> > > +     cntl = (((a6xx_gpu->preempt_level << 6) & 0xC0) |
> > > +             ((a6xx_gpu->skip_save_restore << 9) & 0x200) |
> > > +             ((a6xx_gpu->uses_gmem << 8) & 0x100) | 0x1);
> > > +
> > > +     /* Get the next ring to preempt to */
> > > +     ring = get_next_ring(gpu);
> > > +
> > > +     /*
> > > +      * If no ring is populated or the highest priority ring is the current
> > > +      * one do nothing except to update the wptr to the latest and greatest
> > > +      */
> > > +     if (!ring || (a6xx_gpu->cur_ring == ring)) {
> > > +             set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
> > > +             update_wptr(gpu, a6xx_gpu->cur_ring);
> > > +             set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > > +             spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > > +             return;
> > > +     }
> > > +
> > > +     spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > > +
> > > +     spin_lock_irqsave(&ring->preempt_lock, flags);
> > > +
> > > +     struct a7xx_cp_smmu_info *smmu_info_ptr =
> > > +             a6xx_gpu->preempt[ring->id] + PREEMPT_OFFSET_SMMU_INFO;
> > > +     struct a6xx_preempt_record *record_ptr =
> > > +             a6xx_gpu->preempt[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > > +     u64 ttbr0 = ring->memptrs->ttbr0;
> > > +     u32 context_idr = ring->memptrs->context_idr;
> > > +
> > > +     smmu_info_ptr->ttbr0 = ttbr0;
> > > +     smmu_info_ptr->context_idr = context_idr;
> > > +     record_ptr->wptr = get_wptr(ring);
> > > +
> > > +     /*
> > > +      * The GPU will write the wptr we set above when we preempt. Reset
> > > +      * skip_inline_wptr to make sure that we don't write WPTR to the same
> > > +      * thing twice. It's still possible subsequent submissions will update
> > > +      * wptr again, in which case they will set the flag to true. This has
> > > +      * to be protected by the lock for setting the flag and updating wptr
> > > +      * to be atomic.
> > > +      */
> > > +     ring->skip_inline_wptr = false;
> > > +
> > > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > +
> > > +     gpu_write64(gpu,
> > > +             REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO,
> > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_SMMU_INFO);
> > > +
> > > +     gpu_write64(gpu,
> > > +             REG_A6XX_CP_CONTEXT_SWITCH_PRIV_NON_SECURE_RESTORE_ADDR,
> > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE);
> > > +
> > > +     preempt_offset_priv_secure =
> > > +             PREEMPT_OFFSET_PRIV_SECURE(adreno_gpu->info->preempt_record_size);
> > > +     gpu_write64(gpu,
> > > +             REG_A6XX_CP_CONTEXT_SWITCH_PRIV_SECURE_RESTORE_ADDR,
> > > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure);
> > > +
> > > +     /*
> > > +      * Use the user context iova from the scratch memory that the CP may
> > > +      * have written as part of the ring switch out.
> > > +      */
> > > +     user_ctx_iova = *((uint64_t *)a6xx_gpu->scratch_ptr + ring->id);
> > > +
> > > +     gpu_write64(gpu,
> > > +             REG_A6XX_CP_CONTEXT_SWITCH_NON_PRIV_RESTORE_ADDR,
> > > +             user_ctx_iova);
> > > +
> > > +     a6xx_gpu->next_ring = ring;
> > > +
> > > +     /* Start a timer to catch a stuck preemption */
> > > +     mod_timer(&a6xx_gpu->preempt_timer, jiffies + msecs_to_jiffies(10000));
> > > +
> > > +     /* Set the preemption state to triggered */
> > > +     set_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED);
> > > +
> > > +     /* Make sure any previous writes to WPTR are posted */
> > > +     gpu_read(gpu, REG_A6XX_CP_RB_WPTR);
> > > +
> > > +     /* Make sure everything is written before hitting the button */
> > > +     wmb();
> > > +
> > > +     /* Trigger the preemption */
> > > +     gpu_write(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL, cntl);
> > > +}
> > > +
> > > +static int preempt_init_ring(struct a6xx_gpu *a6xx_gpu,
> > > +             struct msm_ringbuffer *ring)
> > > +{
> > > +     struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
> > > +     struct msm_gpu *gpu = &adreno_gpu->base;
> > > +     struct drm_gem_object *bo = NULL;
> > > +     phys_addr_t ttbr;
> > > +     u64 iova = 0;
> > > +     void *ptr;
> > > +     int asid;
> > > +
> > > +     ptr = msm_gem_kernel_new(gpu->dev,
> > > +             PREEMPT_SIZE(adreno_gpu->info->preempt_record_size),
> > > +             MSM_BO_WC | MSM_BO_MAP_PRIV, gpu->aspace, &bo, &iova);
> > > +
> > > +     memset(ptr, 0, PREEMPT_SIZE(adreno_gpu->info->preempt_record_size));
> > > +
> > > +     if (IS_ERR(ptr))
> > > +             return PTR_ERR(ptr);
> > > +
> > > +     a6xx_gpu->preempt_bo[ring->id] = bo;
> > > +     a6xx_gpu->preempt_iova[ring->id] = iova;
> > > +     a6xx_gpu->preempt[ring->id] = ptr;
> > > +
> > > +     struct a7xx_cp_smmu_info *smmu_info_ptr = ptr + PREEMPT_OFFSET_SMMU_INFO;
> > > +     struct a6xx_preempt_record *record_ptr = ptr + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > > +
> > > +     msm_iommu_pagetable_params(gpu->aspace->mmu, &ttbr, &asid);
> > > +
> > > +     smmu_info_ptr->magic = GEN7_CP_SMMU_INFO_MAGIC;
> > > +     smmu_info_ptr->ttbr0 = ttbr;
> > > +     smmu_info_ptr->asid = 0xdecafbad;
> > > +     smmu_info_ptr->context_idr = 0;
> > > +
> > > +     /* Set up the defaults on the preemption record */
> > > +     record_ptr->magic = A6XX_PREEMPT_RECORD_MAGIC;
> > > +     record_ptr->info = 0;
> > > +     record_ptr->data = 0;
> > > +     record_ptr->rptr = 0;
> > > +     record_ptr->wptr = 0;
> > > +     record_ptr->cntl = MSM_GPU_RB_CNTL_DEFAULT;
> > > +     record_ptr->rbase = ring->iova;
> > > +     record_ptr->counter = 0;
> > > +     record_ptr->bv_rptr_addr = rbmemptr(ring, bv_rptr);
> > > +
> > > +     return 0;
> > > +}
> > > +
> > > +void a6xx_preempt_fini(struct msm_gpu *gpu)
> > > +{
> > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > +     int i;
> > > +
> > > +     for (i = 0; i < gpu->nr_rings; i++)
> > > +             msm_gem_kernel_put(a6xx_gpu->preempt_bo[i], gpu->aspace);
> > > +}
> > > +
> > > +void a6xx_preempt_init(struct msm_gpu *gpu)
> > > +{
> > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > +     int i;
> > > +
> > > +     /* No preemption if we only have one ring */
> > > +     if (gpu->nr_rings <= 1)
> > > +             return;
> > > +
> > > +     for (i = 0; i < gpu->nr_rings; i++) {
> > > +             if (preempt_init_ring(a6xx_gpu, gpu->rb[i]))
> > > +                     goto fail;
> > > +     }
> > > +
> > > +     /* TODO: make this configurable? */
> > > +     a6xx_gpu->preempt_level = 1;
> > > +     a6xx_gpu->uses_gmem = 1;
> > > +     a6xx_gpu->skip_save_restore = 1;
> > > +
> > > +     a6xx_gpu->scratch_ptr  = msm_gem_kernel_new(gpu->dev,
> > > +                     gpu->nr_rings * sizeof(uint64_t), MSM_BO_WC,
> > > +                     gpu->aspace, &a6xx_gpu->scratch_bo,
> > > +                     &a6xx_gpu->scratch_iova);
> > > +
> > > +     if (IS_ERR(a6xx_gpu->scratch_ptr))
> > > +             goto fail;
> > > +
> > > +     timer_setup(&a6xx_gpu->preempt_timer, a6xx_preempt_timer, 0);
> > > +
> > > +     return;
> > > +fail:
> > > +     /*
> > > +      * On any failure our adventure is over. Clean up and
> > > +      * set nr_rings to 1 to force preemption off
> > > +      */
> > > +     a6xx_preempt_fini(gpu);
> > > +     gpu->nr_rings = 1;
> > > +
> > > +     return;
> > > +}
> > > +
> > > +void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
> > > +             struct msm_gpu_submitqueue *queue)
> > > +{
> > > +     if (!queue->bo)
> > > +             return;
> > > +
> > > +     msm_gem_kernel_put(queue->bo, gpu->aspace);
> > > +}
> > > +
> > > +int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
> > > +             struct msm_gpu_submitqueue *queue)
> > > +{
> > > +     void *ptr;
> > > +
> > > +     /*
> > > +      * Create a per submitqueue buffer for the CP to save and restore user
> > > +      * specific information such as the VPC streamout data.
> > > +      */
> > > +     ptr = msm_gem_kernel_new(gpu->dev, A6XX_PREEMPT_USER_RECORD_SIZE,
> > > +                     MSM_BO_WC, gpu->aspace, &queue->bo, &queue->bo_iova);
> > > +
> > > +     if (IS_ERR(ptr))
> > > +             return PTR_ERR(ptr);
> > > +
> > > +     return 0;
> > > +}
> > > diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.h b/drivers/gpu/drm/msm/msm_ringbuffer.h
> > > index 40791b2ade46..7dde6a312511 100644
> > > --- a/drivers/gpu/drm/msm/msm_ringbuffer.h
> > > +++ b/drivers/gpu/drm/msm/msm_ringbuffer.h
> > > @@ -36,6 +36,7 @@ struct msm_rbmemptrs {
> > >
> > >       volatile struct msm_gpu_submit_stats stats[MSM_GPU_SUBMIT_STATS_COUNT];
> > >       volatile u64 ttbr0;
> > > +     volatile u32 context_idr;
> > >  };
> > >
> > >  struct msm_cp_state {
> > > @@ -100,6 +101,12 @@ struct msm_ringbuffer {
> > >        * preemption.  Can be aquired from irq context.
> > >        */
> > >       spinlock_t preempt_lock;
> > > +
> > > +     /*
> > > +      * Whether we skipped writing wptr and it needs to be updated in the
> > > +      * future when the ring becomes current.
> > > +      */
> > > +     bool skip_inline_wptr;
> > >  };
> > >
> > >  struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int id,
> > >
> > > --
> > > 2.46.0
> > >
> > >

Antonino Maniscalco Aug. 23, 2024, 12:19 a.m. UTC | #8

On 8/22/24 9:23 PM, Akhil P Oommen wrote:
> On Wed, Aug 21, 2024 at 04:34:15PM +0200, Antonino Maniscalco wrote:
>> On 8/19/24 10:08 PM, Akhil P Oommen wrote:
>>> On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
>>>> This patch implements preemption feature for A6xx targets, this allows
>>>> the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
>>>> hardware as such supports multiple levels of preemption granularities,
>>>> ranging from coarse grained(ringbuffer level) to a more fine grained
>>>> such as draw-call level or a bin boundary level preemption. This patch
>>>> enables the basic preemption level, with more fine grained preemption
>>>> support to follow.
>>>>
>>>> Signed-off-by: Sharat Masetty <[e-mail]>
>>>> Signed-off-by: Antonino Maniscalco <[e-mail]>
>>>> ---
>>>
>>> No postamble packets which resets perfcounters? It is necessary. Also, I
>>> think we should disable preemption during profiling like we disable slumber.
>>>
>>> -Akhil.
>>>
>>
>> You mention that we disable slumber during profiling however I wasn't able
>> to find code doing that. Can you please clarify which code you are referring
>> to or a mechanism through which the kernel can know when we are profiling?
>>
> 
> Please check msm_file_private_set_sysprof().
> 
> -Akhil
> 
>> Best regards,
>> -- 
>> Antonino Maniscalco <[e-mail]>
>>

I see, thank you. So as Connor said in the other message we want to 
distinguish the case of system profiling where we do want preemption and 
application level profiling where we do not want it. So sysprof is not 
the condition we want to check for to disable preemption, correct?

Best regards,

Connor Abbott Aug. 23, 2024, 9:21 a.m. UTC | #9

On Thu, Aug 22, 2024 at 9:06 PM Akhil P Oommen <[e-mail]> wrote:
>
> On Wed, Aug 21, 2024 at 05:02:56PM +0100, Connor Abbott wrote:
> > On Mon, Aug 19, 2024 at 9:09 PM Akhil P Oommen <[e-mail]> wrote:
> > >
> > > On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
> > > > This patch implements preemption feature for A6xx targets, this allows
> > > > the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
> > > > hardware as such supports multiple levels of preemption granularities,
> > > > ranging from coarse grained(ringbuffer level) to a more fine grained
> > > > such as draw-call level or a bin boundary level preemption. This patch
> > > > enables the basic preemption level, with more fine grained preemption
> > > > support to follow.
> > > >
> > > > Signed-off-by: Sharat Masetty <[e-mail]>
> > > > Signed-off-by: Antonino Maniscalco <[e-mail]>
> > > > ---
> > >
> > > No postamble packets which resets perfcounters? It is necessary. Also, I
> > > think we should disable preemption during profiling like we disable slumber.
> > >
> > > -Akhil.
> >
> > I don't see anything in kgsl which disables preemption during
> > profiling. It disables resetting perfcounters when doing system-wide
> > profiling, like freedreno, and in that case I assume preempting is
> > fine because the system profiler has a complete view of everything and
> > should "see" preemptions through the traces. For something like
> > VK_KHR_performance_query I suppose we'd want to disable preemption
> > because we disable saving/restoring perf counters, but that has to
> > happen in userspace because the kernel doesn't know what userspace
> > does.
> >
>
> KGSL does some sort of arbitration of perfcounter configurations and
> adds the select/enablement reg configuration as part of dynamic
> power up register list which we are not doing here. Is this something
> you are taking care of from userspace via preamble?
>
> -Akhil

I don't think we have to take care of that in userspace, because Mesa
will always configure the counter registers before reading them in the
same submission, and if it gets preempted in the meantime then we're
toast anyways (due to not saving/restoring perf counters). kgsl sets
them from userspace, which is why it has to do something to set them
after IFPC slumber or a context switch when the HW state is gone.
Also, because the upstream approach doesn't play nicely with system
profilers like perfetto, VK_KHR_performance_query is hidden by default
behind a debug flag in turnip. So there's already an element of "this
is unsupported, you have to know what you're doing to use it."

Connor

>
> > Connor
> >
> > >
> > > >  drivers/gpu/drm/msm/Makefile              |   1 +
> > > >  drivers/gpu/drm/msm/adreno/a6xx_gpu.c     | 323 +++++++++++++++++++++-
> > > >  drivers/gpu/drm/msm/adreno/a6xx_gpu.h     | 168 ++++++++++++
> > > >  drivers/gpu/drm/msm/adreno/a6xx_preempt.c | 434 ++++++++++++++++++++++++++++++
> > > >  drivers/gpu/drm/msm/msm_ringbuffer.h      |   7 +
> > > >  5 files changed, 924 insertions(+), 9 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile
> > > > index f5e2838c6a76..32e915109a59 100644
> > > > --- a/drivers/gpu/drm/msm/Makefile
> > > > +++ b/drivers/gpu/drm/msm/Makefile
> > > > @@ -23,6 +23,7 @@ adreno-y := \
> > > >       adreno/a6xx_gpu.o \
> > > >       adreno/a6xx_gmu.o \
> > > >       adreno/a6xx_hfi.o \
> > > > +     adreno/a6xx_preempt.o \
> > > >
> > > >  adreno-$(CONFIG_DEBUG_FS) += adreno/a5xx_debugfs.o \
> > > >
> > > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > > index 32a4faa93d7f..1a90db5759b8 100644
> > > > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > > @@ -16,6 +16,83 @@
> > > >
> > > >  #define GPU_PAS_ID 13
> > > >
> > > > +/* IFPC & Preemption static powerup restore list */
> > > > +static const uint32_t a7xx_pwrup_reglist[] = {
> > > > +     REG_A6XX_UCHE_TRAP_BASE,
> > > > +     REG_A6XX_UCHE_TRAP_BASE + 1,
> > > > +     REG_A6XX_UCHE_WRITE_THRU_BASE,
> > > > +     REG_A6XX_UCHE_WRITE_THRU_BASE + 1,
> > > > +     REG_A6XX_UCHE_GMEM_RANGE_MIN,
> > > > +     REG_A6XX_UCHE_GMEM_RANGE_MIN + 1,
> > > > +     REG_A6XX_UCHE_GMEM_RANGE_MAX,
> > > > +     REG_A6XX_UCHE_GMEM_RANGE_MAX + 1,
> > > > +     REG_A6XX_UCHE_CACHE_WAYS,
> > > > +     REG_A6XX_UCHE_MODE_CNTL,
> > > > +     REG_A6XX_RB_NC_MODE_CNTL,
> > > > +     REG_A6XX_RB_CMP_DBG_ECO_CNTL,
> > > > +     REG_A7XX_GRAS_NC_MODE_CNTL,
> > > > +     REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE,
> > > > +     REG_A6XX_UCHE_GBIF_GX_CONFIG,
> > > > +     REG_A6XX_UCHE_CLIENT_PF,
> > > > +};
> > > > +
> > > > +static const uint32_t a7xx_ifpc_pwrup_reglist[] = {
> > > > +     REG_A6XX_TPL1_NC_MODE_CNTL,
> > > > +     REG_A6XX_SP_NC_MODE_CNTL,
> > > > +     REG_A6XX_CP_DBG_ECO_CNTL,
> > > > +     REG_A6XX_CP_PROTECT_CNTL,
> > > > +     REG_A6XX_CP_PROTECT(0),
> > > > +     REG_A6XX_CP_PROTECT(1),
> > > > +     REG_A6XX_CP_PROTECT(2),
> > > > +     REG_A6XX_CP_PROTECT(3),
> > > > +     REG_A6XX_CP_PROTECT(4),
> > > > +     REG_A6XX_CP_PROTECT(5),
> > > > +     REG_A6XX_CP_PROTECT(6),
> > > > +     REG_A6XX_CP_PROTECT(7),
> > > > +     REG_A6XX_CP_PROTECT(8),
> > > > +     REG_A6XX_CP_PROTECT(9),
> > > > +     REG_A6XX_CP_PROTECT(10),
> > > > +     REG_A6XX_CP_PROTECT(11),
> > > > +     REG_A6XX_CP_PROTECT(12),
> > > > +     REG_A6XX_CP_PROTECT(13),
> > > > +     REG_A6XX_CP_PROTECT(14),
> > > > +     REG_A6XX_CP_PROTECT(15),
> > > > +     REG_A6XX_CP_PROTECT(16),
> > > > +     REG_A6XX_CP_PROTECT(17),
> > > > +     REG_A6XX_CP_PROTECT(18),
> > > > +     REG_A6XX_CP_PROTECT(19),
> > > > +     REG_A6XX_CP_PROTECT(20),
> > > > +     REG_A6XX_CP_PROTECT(21),
> > > > +     REG_A6XX_CP_PROTECT(22),
> > > > +     REG_A6XX_CP_PROTECT(23),
> > > > +     REG_A6XX_CP_PROTECT(24),
> > > > +     REG_A6XX_CP_PROTECT(25),
> > > > +     REG_A6XX_CP_PROTECT(26),
> > > > +     REG_A6XX_CP_PROTECT(27),
> > > > +     REG_A6XX_CP_PROTECT(28),
> > > > +     REG_A6XX_CP_PROTECT(29),
> > > > +     REG_A6XX_CP_PROTECT(30),
> > > > +     REG_A6XX_CP_PROTECT(31),
> > > > +     REG_A6XX_CP_PROTECT(32),
> > > > +     REG_A6XX_CP_PROTECT(33),
> > > > +     REG_A6XX_CP_PROTECT(34),
> > > > +     REG_A6XX_CP_PROTECT(35),
> > > > +     REG_A6XX_CP_PROTECT(36),
> > > > +     REG_A6XX_CP_PROTECT(37),
> > > > +     REG_A6XX_CP_PROTECT(38),
> > > > +     REG_A6XX_CP_PROTECT(39),
> > > > +     REG_A6XX_CP_PROTECT(40),
> > > > +     REG_A6XX_CP_PROTECT(41),
> > > > +     REG_A6XX_CP_PROTECT(42),
> > > > +     REG_A6XX_CP_PROTECT(43),
> > > > +     REG_A6XX_CP_PROTECT(44),
> > > > +     REG_A6XX_CP_PROTECT(45),
> > > > +     REG_A6XX_CP_PROTECT(46),
> > > > +     REG_A6XX_CP_PROTECT(47),
> > > > +     REG_A6XX_CP_AHB_CNTL,
> > > > +};
> > > > +
> > > > +
> > > >  static inline bool _a6xx_check_idle(struct msm_gpu *gpu)
> > > >  {
> > > >       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > @@ -68,6 +145,8 @@ static void update_shadow_rptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > > >
> > > >  static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > > >  {
> > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > >       uint32_t wptr;
> > > >       unsigned long flags;
> > > >
> > > > @@ -81,12 +160,26 @@ static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > > >       /* Make sure to wrap wptr if we need to */
> > > >       wptr = get_wptr(ring);
> > > >
> > > > -     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > > -
> > > >       /* Make sure everything is posted before making a decision */
> > > >       mb();
> > > >
> > > > -     gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > > > +     /* Update HW if this is the current ring and we are not in preempt*/
> > > > +     if (!a6xx_in_preempt(a6xx_gpu)) {
> > > > +             /*
> > > > +              * Order the reads of the preempt state and cur_ring. This
> > > > +              * matches the barrier after writing cur_ring.
> > > > +              */
> > > > +             rmb();
> > > > +
> > > > +             if (a6xx_gpu->cur_ring == ring)
> > > > +                     gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > > > +             else
> > > > +                     ring->skip_inline_wptr = true;
> > > > +     } else {
> > > > +             ring->skip_inline_wptr = true;
> > > > +     }
> > > > +
> > > > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > >  }
> > > >
> > > >  static void get_stats_counter(struct msm_ringbuffer *ring, u32 counter,
> > > > @@ -138,12 +231,14 @@ static void a6xx_set_pagetable(struct a6xx_gpu *a6xx_gpu,
> > > >
> > > >       /*
> > > >        * Write the new TTBR0 to the memstore. This is good for debugging.
> > > > +      * Needed for preemption
> > > >        */
> > > > -     OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > > > +     OUT_PKT7(ring, CP_MEM_WRITE, 5);
> > > >       OUT_RING(ring, CP_MEM_WRITE_0_ADDR_LO(lower_32_bits(memptr)));
> > > >       OUT_RING(ring, CP_MEM_WRITE_1_ADDR_HI(upper_32_bits(memptr)));
> > > >       OUT_RING(ring, lower_32_bits(ttbr));
> > > > -     OUT_RING(ring, (asid << 16) | upper_32_bits(ttbr));
> > > > +     OUT_RING(ring, upper_32_bits(ttbr));
> > > > +     OUT_RING(ring, ctx->seqno);
> > > >
> > > >       /*
> > > >        * Sync both threads after switching pagetables and enable BR only
> > > > @@ -268,12 +363,55 @@ static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > >       a6xx_flush(gpu, ring);
> > > >  }
> > > >
> > > > +static void a6xx_emit_set_pseudo_reg(struct msm_ringbuffer *ring,
> > > > +             struct a6xx_gpu *a6xx_gpu, struct msm_gpu_submitqueue *queue)
> > > > +{
> > > > +     u64 preempt_offset_priv_secure;
> > > > +
> > > > +     OUT_PKT7(ring, CP_SET_PSEUDO_REG, 15);
> > > > +
> > > > +     OUT_RING(ring, SMMU_INFO);
> > > > +     /* don't save SMMU, we write the record from the kernel instead */
> > > > +     OUT_RING(ring, 0);
> > > > +     OUT_RING(ring, 0);
> > > > +
> > > > +     /* privileged and non secure buffer save */
> > > > +     OUT_RING(ring, NON_SECURE_SAVE_ADDR);
> > > > +     OUT_RING(ring, lower_32_bits(
> > > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE));
> > > > +     OUT_RING(ring, upper_32_bits(
> > > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE));
> > > > +     OUT_RING(ring, SECURE_SAVE_ADDR);
> > > > +     preempt_offset_priv_secure =
> > > > +             PREEMPT_OFFSET_PRIV_SECURE(a6xx_gpu->base.info->preempt_record_size);
> > > > +     OUT_RING(ring, lower_32_bits(
> > > > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure));
> > > > +     OUT_RING(ring, upper_32_bits(
> > > > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure));
> > > > +
> > > > +     /* user context buffer save */
> > > > +     OUT_RING(ring, NON_PRIV_SAVE_ADDR);
> > > > +     if (queue) {
> > > > +             OUT_RING(ring, lower_32_bits(queue->bo_iova));
> > > > +             OUT_RING(ring, upper_32_bits(queue->bo_iova));
> > > > +     } else {
> > > > +             OUT_RING(ring, 0);
> > > > +             OUT_RING(ring, 0);
> > > > +     }
> > > > +
> > > > +     OUT_RING(ring, COUNTER);
> > > > +     /* seems OK to set to 0 to disable it */
> > > > +     OUT_RING(ring, 0);
> > > > +     OUT_RING(ring, 0);
> > > > +}
> > > > +
> > > >  static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > >  {
> > > >       unsigned int index = submit->seqno % MSM_GPU_SUBMIT_STATS_COUNT;
> > > >       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > >       struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > >       struct msm_ringbuffer *ring = submit->ring;
> > > > +     uint64_t scratch_dest = SCRATCH_USER_CTX_IOVA(ring->id, a6xx_gpu);
> > > >       unsigned int i, ibs = 0;
> > > >
> > > >       /*
> > > > @@ -283,6 +421,25 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > >       OUT_PKT7(ring, CP_THREAD_CONTROL, 1);
> > > >       OUT_RING(ring, CP_THREAD_CONTROL_0_SYNC_THREADS | CP_SET_THREAD_BR);
> > > >
> > > > +     /*
> > > > +      * If preemption is enabled, then set the pseudo register for the save
> > > > +      * sequence
> > > > +      */
> > > > +     if (gpu->nr_rings > 1) {
> > > > +             a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, submit->queue);
> > > > +
> > > > +             /*
> > > > +              * Ask CP to save the user context buffer's iova address to a
> > > > +              * scratch memory region, this is needed if the CP preempts
> > > > +              * this ring in between this submit's IB list.
> > > > +              */
> > > > +             OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > > > +             OUT_RING(ring, lower_32_bits(scratch_dest));
> > > > +             OUT_RING(ring, upper_32_bits(scratch_dest));
> > > > +             OUT_RING(ring, lower_32_bits(submit->queue->bo_iova));
> > > > +             OUT_RING(ring, upper_32_bits(submit->queue->bo_iova));
> > > > +     }
> > > > +
> > > >       a6xx_set_pagetable(a6xx_gpu, ring, submit->queue->ctx);
> > > >
> > > >       get_stats_counter(ring, REG_A7XX_RBBM_PERFCTR_CP(0),
> > > > @@ -376,6 +533,8 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > >       OUT_RING(ring, upper_32_bits(rbmemptr(ring, bv_fence)));
> > > >       OUT_RING(ring, submit->seqno);
> > > >
> > > > +     a6xx_gpu->last_seqno[ring->id] = submit->seqno;
> > > > +
> > > >       /* write the ringbuffer timestamp */
> > > >       OUT_PKT7(ring, CP_EVENT_WRITE, 4);
> > > >       OUT_RING(ring, CACHE_CLEAN | CP_EVENT_WRITE_0_IRQ | BIT(27));
> > > > @@ -389,10 +548,42 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > >       OUT_PKT7(ring, CP_SET_MARKER, 1);
> > > >       OUT_RING(ring, 0x100); /* IFPC enable */
> > > >
> > > > +     /* If preemption is enabled */
> > > > +     if (gpu->nr_rings > 1) {
> > > > +             /*
> > > > +              * Reset the scratch region as we are done with the
> > > > +              * IB list of this submission
> > > > +              */
> > > > +             OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > > > +             OUT_RING(ring, lower_32_bits(scratch_dest));
> > > > +             OUT_RING(ring, upper_32_bits(scratch_dest));
> > > > +             OUT_RING(ring, 0x00);
> > > > +             OUT_RING(ring, 0x00);
> > > > +
> > > > +             /* Yield the floor on command completion */
> > > > +             OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
> > > > +
> > > > +             /*
> > > > +              * If dword[2:1] are non zero, they specify an address for
> > > > +              * the CP to write the value of dword[3] to on preemption
> > > > +              * complete. Write 0 to skip the write
> > > > +              */
> > > > +             OUT_RING(ring, 0x00);
> > > > +             OUT_RING(ring, 0x00);
> > > > +             /* Data value - not used if the address above is 0 */
> > > > +             OUT_RING(ring, 0x01);
> > > > +             /* generate interrupt on preemption completion */
> > > > +             OUT_RING(ring, 0x00);
> > > > +     }
> > > > +
> > > > +
> > > >       trace_msm_gpu_submit_flush(submit,
> > > >               gpu_read64(gpu, REG_A6XX_CP_ALWAYS_ON_COUNTER));
> > > >
> > > >       a6xx_flush(gpu, ring);
> > > > +
> > > > +     /* Check to see if we need to start preemption */
> > > > +     a6xx_preempt_trigger(gpu);
> > > >  }
> > > >
> > > >  static void a6xx_set_hwcg(struct msm_gpu *gpu, bool state)
> > > > @@ -588,6 +779,89 @@ static void a6xx_set_ubwc_config(struct msm_gpu *gpu)
> > > >                 adreno_gpu->ubwc_config.min_acc_len << 23 | hbb_lo << 21);
> > > >  }
> > > >
> > > > +static void a7xx_patch_pwrup_reglist(struct msm_gpu *gpu)
> > > > +{
> > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > +     struct adreno_reglist_list reglist[2];
> > > > +     void *ptr = a6xx_gpu->pwrup_reglist_ptr;
> > > > +     struct cpu_gpu_lock *lock = ptr;
> > > > +     u32 *dest = (u32 *)&lock->regs[0];
> > > > +     int i, j;
> > > > +
> > > > +     lock->gpu_req = lock->cpu_req = lock->turn = 0;
> > > > +     lock->ifpc_list_len = ARRAY_SIZE(a7xx_ifpc_pwrup_reglist);
> > > > +     lock->preemption_list_len = ARRAY_SIZE(a7xx_pwrup_reglist);
> > > > +
> > > > +     /* Static IFPC-only registers */
> > > > +     reglist[0].regs = a7xx_ifpc_pwrup_reglist;
> > > > +     reglist[0].count = ARRAY_SIZE(a7xx_ifpc_pwrup_reglist);
> > > > +     lock->ifpc_list_len = reglist[0].count;
> > > > +
> > > > +     /* Static IFPC + preemption registers */
> > > > +     reglist[1].regs = a7xx_pwrup_reglist;
> > > > +     reglist[1].count = ARRAY_SIZE(a7xx_pwrup_reglist);
> > > > +     lock->preemption_list_len = reglist[1].count;
> > > > +
> > > > +     /*
> > > > +      * For each entry in each of the lists, write the offset and the current
> > > > +      * register value into the GPU buffer
> > > > +      */
> > > > +     for (i = 0; i < 2; i++) {
> > > > +             const u32 *r = reglist[i].regs;
> > > > +
> > > > +             for (j = 0; j < reglist[i].count; j++) {
> > > > +                     *dest++ = r[j];
> > > > +                     *dest++ = gpu_read(gpu, r[j]);
> > > > +             }
> > > > +     }
> > > > +
> > > > +     /*
> > > > +      * The overall register list is composed of
> > > > +      * 1. Static IFPC-only registers
> > > > +      * 2. Static IFPC + preemption registers
> > > > +      * 3. Dynamic IFPC + preemption registers (ex: perfcounter selects)
> > > > +      *
> > > > +      * The first two lists are static. Size of these lists are stored as
> > > > +      * number of pairs in ifpc_list_len and preemption_list_len
> > > > +      * respectively. With concurrent binning, Some of the perfcounter
> > > > +      * registers being virtualized, CP needs to know the pipe id to program
> > > > +      * the aperture inorder to restore the same. Thus, third list is a
> > > > +      * dynamic list with triplets as
> > > > +      * (<aperture, shifted 12 bits> <address> <data>), and the length is
> > > > +      * stored as number for triplets in dynamic_list_len.
> > > > +      */
> > > > +     lock->dynamic_list_len = 0;
> > > > +}
> > > > +
> > > > +static int a7xx_preempt_start(struct msm_gpu *gpu)
> > > > +{
> > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > +     struct msm_ringbuffer *ring = gpu->rb[0];
> > > > +
> > > > +     if (gpu->nr_rings <= 1)
> > > > +             return 0;
> > > > +
> > > > +     /* Turn CP protection off */
> > > > +     OUT_PKT7(ring, CP_SET_PROTECTED_MODE, 1);
> > > > +     OUT_RING(ring, 0);
> > > > +
> > > > +     a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, NULL);
> > > > +
> > > > +     /* Yield the floor on command completion */
> > > > +     OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
> > > > +     OUT_RING(ring, 0x00);
> > > > +     OUT_RING(ring, 0x00);
> > > > +     OUT_RING(ring, 0x01);
> > > > +     /* Generate interrupt on preemption completion */
> > > > +     OUT_RING(ring, 0x00);
> > > > +
> > > > +     a6xx_flush(gpu, ring);
> > > > +
> > > > +     return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
> > > > +}
> > > > +
> > > >  static int a6xx_cp_init(struct msm_gpu *gpu)
> > > >  {
> > > >       struct msm_ringbuffer *ring = gpu->rb[0];
> > > > @@ -619,6 +893,8 @@ static int a6xx_cp_init(struct msm_gpu *gpu)
> > > >
> > > >  static int a7xx_cp_init(struct msm_gpu *gpu)
> > > >  {
> > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > >       struct msm_ringbuffer *ring = gpu->rb[0];
> > > >       u32 mask;
> > > >
> > > > @@ -626,6 +902,8 @@ static int a7xx_cp_init(struct msm_gpu *gpu)
> > > >       OUT_PKT7(ring, CP_THREAD_CONTROL, 1);
> > > >       OUT_RING(ring, BIT(27));
> > > >
> > > > +     a7xx_patch_pwrup_reglist(gpu);
> > > > +
> > > >       OUT_PKT7(ring, CP_ME_INIT, 7);
> > > >
> > > >       /* Use multiple HW contexts */
> > > > @@ -656,11 +934,11 @@ static int a7xx_cp_init(struct msm_gpu *gpu)
> > > >
> > > >       /* *Don't* send a power up reg list for concurrent binning (TODO) */
> > > >       /* Lo address */
> > > > -     OUT_RING(ring, 0x00000000);
> > > > +     OUT_RING(ring, lower_32_bits(a6xx_gpu->pwrup_reglist_iova));
> > > >       /* Hi address */
> > > > -     OUT_RING(ring, 0x00000000);
> > > > +     OUT_RING(ring, upper_32_bits(a6xx_gpu->pwrup_reglist_iova));
> > > >       /* BIT(31) set => read the regs from the list */
> > > > -     OUT_RING(ring, 0x00000000);
> > > > +     OUT_RING(ring, BIT(31));
> > > >
> > > >       a6xx_flush(gpu, ring);
> > > >       return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
> > > > @@ -784,6 +1062,16 @@ static int a6xx_ucode_load(struct msm_gpu *gpu)
> > > >               msm_gem_object_set_name(a6xx_gpu->shadow_bo, "shadow");
> > > >       }
> > > >
> > > > +     a6xx_gpu->pwrup_reglist_ptr = msm_gem_kernel_new(gpu->dev, PAGE_SIZE,
> > > > +                                                      MSM_BO_WC  | MSM_BO_MAP_PRIV,
> > > > +                                                      gpu->aspace, &a6xx_gpu->pwrup_reglist_bo,
> > > > +                                                      &a6xx_gpu->pwrup_reglist_iova);
> > > > +
> > > > +     if (IS_ERR(a6xx_gpu->pwrup_reglist_ptr))
> > > > +             return PTR_ERR(a6xx_gpu->pwrup_reglist_ptr);
> > > > +
> > > > +     msm_gem_object_set_name(a6xx_gpu->pwrup_reglist_bo, "pwrup_reglist");
> > > > +
> > > >       return 0;
> > > >  }
> > > >
> > > > @@ -1127,6 +1415,8 @@ static int hw_init(struct msm_gpu *gpu)
> > > >       if (a6xx_gpu->shadow_bo) {
> > > >               gpu_write64(gpu, REG_A6XX_CP_RB_RPTR_ADDR,
> > > >                       shadowptr(a6xx_gpu, gpu->rb[0]));
> > > > +             for (unsigned int i = 0; i < gpu->nr_rings; i++)
> > > > +                     a6xx_gpu->shadow[i] = 0;
> > > >       }
> > > >
> > > >       /* ..which means "always" on A7xx, also for BV shadow */
> > > > @@ -1135,6 +1425,8 @@ static int hw_init(struct msm_gpu *gpu)
> > > >                           rbmemptr(gpu->rb[0], bv_rptr));
> > > >       }
> > > >
> > > > +     a6xx_preempt_hw_init(gpu);
> > > > +
> > > >       /* Always come up on rb 0 */
> > > >       a6xx_gpu->cur_ring = gpu->rb[0];
> > > >
> > > > @@ -1180,6 +1472,10 @@ static int hw_init(struct msm_gpu *gpu)
> > > >  out:
> > > >       if (adreno_has_gmu_wrapper(adreno_gpu))
> > > >               return ret;
> > > > +
> > > > +     /* Last step - yield the ringbuffer */
> > > > +     a7xx_preempt_start(gpu);
> > > > +
> > > >       /*
> > > >        * Tell the GMU that we are done touching the GPU and it can start power
> > > >        * management
> > > > @@ -1557,8 +1853,13 @@ static irqreturn_t a6xx_irq(struct msm_gpu *gpu)
> > > >       if (status & A6XX_RBBM_INT_0_MASK_SWFUSEVIOLATION)
> > > >               a7xx_sw_fuse_violation_irq(gpu);
> > > >
> > > > -     if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS)
> > > > +     if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS) {
> > > >               msm_gpu_retire(gpu);
> > > > +             a6xx_preempt_trigger(gpu);
> > > > +     }
> > > > +
> > > > +     if (status & A6XX_RBBM_INT_0_MASK_CP_SW)
> > > > +             a6xx_preempt_irq(gpu);
> > > >
> > > >       return IRQ_HANDLED;
> > > >  }
> > > > @@ -2165,6 +2466,8 @@ static const struct adreno_gpu_funcs funcs = {
> > > >               .active_ring = a6xx_active_ring,
> > > >               .irq = a6xx_irq,
> > > >               .destroy = a6xx_destroy,
> > > > +             .submitqueue_setup = a6xx_preempt_submitqueue_setup,
> > > > +             .submitqueue_close = a6xx_preempt_submitqueue_close,
> > > >  #if defined(CONFIG_DRM_MSM_GPU_STATE)
> > > >               .show = a6xx_show,
> > > >  #endif
> > > > @@ -2331,6 +2634,8 @@ struct msm_gpu *a6xx_gpu_init(struct drm_device *dev)
> > > >                               a6xx_fault_handler);
> > > >
> > > >       a6xx_calc_ubwc_config(adreno_gpu);
> > > > +     /* Set up the preemption specific bits and pieces for each ringbuffer */
> > > > +     a6xx_preempt_init(gpu);
> > > >
> > > >       return gpu;
> > > >  }
> > > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > > > index e3e5c53ae8af..652e49f01428 100644
> > > > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > > > @@ -12,6 +12,31 @@
> > > >
> > > >  extern bool hang_debug;
> > > >
> > > > +struct cpu_gpu_lock {
> > > > +     uint32_t gpu_req;
> > > > +     uint32_t cpu_req;
> > > > +     uint32_t turn;
> > > > +     union {
> > > > +             struct {
> > > > +                     uint16_t list_length;
> > > > +                     uint16_t list_offset;
> > > > +             };
> > > > +             struct {
> > > > +                     uint8_t ifpc_list_len;
> > > > +                     uint8_t preemption_list_len;
> > > > +                     uint16_t dynamic_list_len;
> > > > +             };
> > > > +     };
> > > > +     uint64_t regs[62];
> > > > +};
> > > > +
> > > > +struct adreno_reglist_list {
> > > > +     /** @reg: List of register **/
> > > > +     const u32 *regs;
> > > > +     /** @count: Number of registers in the list **/
> > > > +     u32 count;
> > > > +};
> > > > +
> > > >  /**
> > > >   * struct a6xx_info - a6xx specific information from device table
> > > >   *
> > > > @@ -31,6 +56,24 @@ struct a6xx_gpu {
> > > >       uint64_t sqe_iova;
> > > >
> > > >       struct msm_ringbuffer *cur_ring;
> > > > +     struct msm_ringbuffer *next_ring;
> > > > +
> > > > +     struct drm_gem_object *preempt_bo[MSM_GPU_MAX_RINGS];
> > > > +     void *preempt[MSM_GPU_MAX_RINGS];
> > > > +     uint64_t preempt_iova[MSM_GPU_MAX_RINGS];
> > > > +     uint32_t last_seqno[MSM_GPU_MAX_RINGS];
> > > > +
> > > > +     atomic_t preempt_state;
> > > > +     spinlock_t eval_lock;
> > > > +     struct timer_list preempt_timer;
> > > > +
> > > > +     unsigned int preempt_level;
> > > > +     bool uses_gmem;
> > > > +     bool skip_save_restore;
> > > > +
> > > > +     struct drm_gem_object *scratch_bo;
> > > > +     void *scratch_ptr;
> > > > +     uint64_t scratch_iova;
> > > >
> > > >       struct a6xx_gmu gmu;
> > > >
> > > > @@ -38,6 +81,10 @@ struct a6xx_gpu {
> > > >       uint64_t shadow_iova;
> > > >       uint32_t *shadow;
> > > >
> > > > +     struct drm_gem_object *pwrup_reglist_bo;
> > > > +     void *pwrup_reglist_ptr;
> > > > +     uint64_t pwrup_reglist_iova;
> > > > +
> > > >       bool has_whereami;
> > > >
> > > >       void __iomem *llc_mmio;
> > > > @@ -49,6 +96,108 @@ struct a6xx_gpu {
> > > >
> > > >  #define to_a6xx_gpu(x) container_of(x, struct a6xx_gpu, base)
> > > >
> > > > +#define SCRATCH_USER_CTX_IOVA(ring_id, a6xx_gpu) \
> > > > +     (a6xx_gpu->scratch_iova + (ring_id * sizeof(uint64_t)))
> > > > +
> > > > +/*
> > > > + * In order to do lockless preemption we use a simple state machine to progress
> > > > + * through the process.
> > > > + *
> > > > + * PREEMPT_NONE - no preemption in progress.  Next state START.
> > > > + * PREEMPT_START - The trigger is evaluating if preemption is possible. Next
> > > > + * states: TRIGGERED, NONE
> > > > + * PREEMPT_FINISH - An intermediate state before moving back to NONE. Next
> > > > + * state: NONE.
> > > > + * PREEMPT_TRIGGERED: A preemption has been executed on the hardware. Next
> > > > + * states: FAULTED, PENDING
> > > > + * PREEMPT_FAULTED: A preemption timed out (never completed). This will trigger
> > > > + * recovery.  Next state: N/A
> > > > + * PREEMPT_PENDING: Preemption complete interrupt fired - the callback is
> > > > + * checking the success of the operation. Next state: FAULTED, NONE.
> > > > + */
> > > > +
> > > > +enum a6xx_preempt_state {
> > > > +     PREEMPT_NONE = 0,
> > > > +     PREEMPT_START,
> > > > +     PREEMPT_FINISH,
> > > > +     PREEMPT_TRIGGERED,
> > > > +     PREEMPT_FAULTED,
> > > > +     PREEMPT_PENDING,
> > > > +};
> > > > +
> > > > +/*
> > > > + * struct a6xx_preempt_record is a shared buffer between the microcode and the
> > > > + * CPU to store the state for preemption. The record itself is much larger
> > > > + * (2112k) but most of that is used by the CP for storage.
> > > > + *
> > > > + * There is a preemption record assigned per ringbuffer. When the CPU triggers a
> > > > + * preemption, it fills out the record with the useful information (wptr, ring
> > > > + * base, etc) and the microcode uses that information to set up the CP following
> > > > + * the preemption.  When a ring is switched out, the CP will save the ringbuffer
> > > > + * state back to the record. In this way, once the records are properly set up
> > > > + * the CPU can quickly switch back and forth between ringbuffers by only
> > > > + * updating a few registers (often only the wptr).
> > > > + *
> > > > + * These are the CPU aware registers in the record:
> > > > + * @magic: Must always be 0xAE399D6EUL
> > > > + * @info: Type of the record - written 0 by the CPU, updated by the CP
> > > > + * @errno: preemption error record
> > > > + * @data: Data field in YIELD and SET_MARKER packets, Written and used by CP
> > > > + * @cntl: Value of RB_CNTL written by CPU, save/restored by CP
> > > > + * @rptr: Value of RB_RPTR written by CPU, save/restored by CP
> > > > + * @wptr: Value of RB_WPTR written by CPU, save/restored by CP
> > > > + * @_pad: Reserved/padding
> > > > + * @rptr_addr: Value of RB_RPTR_ADDR_LO|HI written by CPU, save/restored by CP
> > > > + * @rbase: Value of RB_BASE written by CPU, save/restored by CP
> > > > + * @counter: GPU address of the storage area for the preemption counters
> > > > + */
> > > > +struct a6xx_preempt_record {
> > > > +     u32 magic;
> > > > +     u32 info;
> > > > +     u32 errno;
> > > > +     u32 data;
> > > > +     u32 cntl;
> > > > +     u32 rptr;
> > > > +     u32 wptr;
> > > > +     u32 _pad;
> > > > +     u64 rptr_addr;
> > > > +     u64 rbase;
> > > > +     u64 counter;
> > > > +     u64 bv_rptr_addr;
> > > > +};
> > > > +
> > > > +#define A6XX_PREEMPT_RECORD_MAGIC 0xAE399D6EUL
> > > > +
> > > > +#define PREEMPT_RECORD_SIZE_FALLBACK(size) \
> > > > +     ((size) == 0 ? 4192 * SZ_1K : (size))
> > > > +
> > > > +#define PREEMPT_OFFSET_SMMU_INFO 0
> > > > +#define PREEMPT_OFFSET_PRIV_NON_SECURE (PREEMPT_OFFSET_SMMU_INFO + 4096)
> > > > +#define PREEMPT_OFFSET_PRIV_SECURE(size) \
> > > > +     (PREEMPT_OFFSET_PRIV_NON_SECURE + PREEMPT_RECORD_SIZE_FALLBACK(size))
> > > > +#define PREEMPT_SIZE(size) \
> > > > +     (PREEMPT_OFFSET_PRIV_SECURE(size) + PREEMPT_RECORD_SIZE_FALLBACK(size))
> > > > +
> > > > +/*
> > > > + * The preemption counter block is a storage area for the value of the
> > > > + * preemption counters that are saved immediately before context switch. We
> > > > + * append it on to the end of the allocation for the preemption record.
> > > > + */
> > > > +#define A6XX_PREEMPT_COUNTER_SIZE (16 * 4)
> > > > +
> > > > +#define A6XX_PREEMPT_USER_RECORD_SIZE (192 * 1024)
> > > > +
> > > > +struct a7xx_cp_smmu_info {
> > > > +     u32 magic;
> > > > +     u32 _pad4;
> > > > +     u64 ttbr0;
> > > > +     u32 asid;
> > > > +     u32 context_idr;
> > > > +     u32 context_bank;
> > > > +};
> > > > +
> > > > +#define GEN7_CP_SMMU_INFO_MAGIC 0x241350d5UL
> > > > +
> > > >  /*
> > > >   * Given a register and a count, return a value to program into
> > > >   * REG_CP_PROTECT_REG(n) - this will block both reads and writes for
> > > > @@ -106,6 +255,25 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
> > > >  int a6xx_gmu_wrapper_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
> > > >  void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu);
> > > >
> > > > +void a6xx_preempt_init(struct msm_gpu *gpu);
> > > > +void a6xx_preempt_hw_init(struct msm_gpu *gpu);
> > > > +void a6xx_preempt_trigger(struct msm_gpu *gpu);
> > > > +void a6xx_preempt_irq(struct msm_gpu *gpu);
> > > > +void a6xx_preempt_fini(struct msm_gpu *gpu);
> > > > +int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
> > > > +             struct msm_gpu_submitqueue *queue);
> > > > +void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
> > > > +             struct msm_gpu_submitqueue *queue);
> > > > +
> > > > +/* Return true if we are in a preempt state */
> > > > +static inline bool a6xx_in_preempt(struct a6xx_gpu *a6xx_gpu)
> > > > +{
> > > > +     int preempt_state = atomic_read(&a6xx_gpu->preempt_state);
> > > > +
> > > > +     return !(preempt_state == PREEMPT_NONE ||
> > > > +                     preempt_state == PREEMPT_FINISH);
> > > > +}
> > > > +
> > > >  void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp,
> > > >                      bool suspended);
> > > >  unsigned long a6xx_gmu_get_freq(struct msm_gpu *gpu);
> > > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_preempt.c b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
> > > > new file mode 100644
> > > > index 000000000000..0d402a3bcf5a
> > > > --- /dev/null
> > > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
> > > > @@ -0,0 +1,434 @@
> > > > +// SPDX-License-Identifier: GPL-2.0
> > > > +/* Copyright (c) 2018, The Linux Foundation. All rights reserved. */
> > > > +/* Copyright (c) 2023 Collabora, Ltd. */
> > > > +/* Copyright (c) 2024 Valve Corporation */
> > > > +
> > > > +#include "msm_gem.h"
> > > > +#include "a6xx_gpu.h"
> > > > +#include "a6xx_gmu.xml.h"
> > > > +#include "msm_mmu.h"
> > > > +
> > > > +#define FENCE_STATUS_WRITEDROPPED0_MASK 0x1
> > > > +#define FENCE_STATUS_WRITEDROPPED1_MASK 0x2
> > > > +
> > > > +/*
> > > > + * Try to transition the preemption state from old to new. Return
> > > > + * true on success or false if the original state wasn't 'old'
> > > > + */
> > > > +static inline bool try_preempt_state(struct a6xx_gpu *a6xx_gpu,
> > > > +             enum a6xx_preempt_state old, enum a6xx_preempt_state new)
> > > > +{
> > > > +     enum a6xx_preempt_state cur = atomic_cmpxchg(&a6xx_gpu->preempt_state,
> > > > +             old, new);
> > > > +
> > > > +     return (cur == old);
> > > > +}
> > > > +
> > > > +/*
> > > > + * Force the preemption state to the specified state.  This is used in cases
> > > > + * where the current state is known and won't change
> > > > + */
> > > > +static inline void set_preempt_state(struct a6xx_gpu *gpu,
> > > > +             enum a6xx_preempt_state new)
> > > > +{
> > > > +     /*
> > > > +      * preempt_state may be read by other cores trying to trigger a
> > > > +      * preemption or in the interrupt handler so barriers are needed
> > > > +      * before...
> > > > +      */
> > > > +     smp_mb__before_atomic();
> > > > +     atomic_set(&gpu->preempt_state, new);
> > > > +     /* ... and after*/
> > > > +     smp_mb__after_atomic();
> > > > +}
> > > > +
> > > > +/* Write the most recent wptr for the given ring into the hardware */
> > > > +static inline void update_wptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > > > +{
> > > > +     unsigned long flags;
> > > > +     uint32_t wptr, cur_wptr;
> > > > +
> > > > +     if (!ring)
> > > > +             return;
> > > > +
> > > > +     spin_lock_irqsave(&ring->preempt_lock, flags);
> > > > +
> > > > +     if (ring->skip_inline_wptr) {
> > > > +             wptr = get_wptr(ring);
> > > > +
> > > > +             gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > > > +
> > > > +             ring->skip_inline_wptr = false;
> > > > +     }
> > > > +
> > > > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > > +}
> > > > +
> > > > +/* Return the highest priority ringbuffer with something in it */
> > > > +static struct msm_ringbuffer *get_next_ring(struct msm_gpu *gpu)
> > > > +{
> > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > +
> > > > +     unsigned long flags;
> > > > +     int i;
> > > > +
> > > > +     for (i = 0; i < gpu->nr_rings; i++) {
> > > > +             bool empty;
> > > > +             struct msm_ringbuffer *ring = gpu->rb[i];
> > > > +
> > > > +             spin_lock_irqsave(&ring->preempt_lock, flags);
> > > > +             empty = (get_wptr(ring) == gpu->funcs->get_rptr(gpu, ring));
> > > > +             if (!empty && ring == a6xx_gpu->cur_ring)
> > > > +                     empty = ring->memptrs->fence == a6xx_gpu->last_seqno[i];
> > > > +             spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > > +
> > > > +             if (!empty)
> > > > +                     return ring;
> > > > +     }
> > > > +
> > > > +     return NULL;
> > > > +}
> > > > +
> > > > +static void a6xx_preempt_timer(struct timer_list *t)
> > > > +{
> > > > +     struct a6xx_gpu *a6xx_gpu = from_timer(a6xx_gpu, t, preempt_timer);
> > > > +     struct msm_gpu *gpu = &a6xx_gpu->base.base;
> > > > +     struct drm_device *dev = gpu->dev;
> > > > +
> > > > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_FAULTED))
> > > > +             return;
> > > > +
> > > > +     dev_err(dev->dev, "%s: preemption timed out\n", gpu->name);
> > > > +     kthread_queue_work(gpu->worker, &gpu->recover_work);
> > > > +}
> > > > +
> > > > +void a6xx_preempt_irq(struct msm_gpu *gpu)
> > > > +{
> > > > +     uint32_t status;
> > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > +     struct drm_device *dev = gpu->dev;
> > > > +
> > > > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_PENDING))
> > > > +             return;
> > > > +
> > > > +     /* Delete the preemption watchdog timer */
> > > > +     del_timer(&a6xx_gpu->preempt_timer);
> > > > +
> > > > +     /*
> > > > +      * The hardware should be setting the stop bit of CP_CONTEXT_SWITCH_CNTL
> > > > +      * to zero before firing the interrupt, but there is a non zero chance
> > > > +      * of a hardware condition or a software race that could set it again
> > > > +      * before we have a chance to finish. If that happens, log and go for
> > > > +      * recovery
> > > > +      */
> > > > +     status = gpu_read(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL);
> > > > +     if (unlikely(status & 0x1)) {
> > > > +             DRM_DEV_ERROR(&gpu->pdev->dev,
> > > > +                                       "!!!!!!!!!!!!!!!! preemption faulted !!!!!!!!!!!!!! irq\n");
> > > > +             set_preempt_state(a6xx_gpu, PREEMPT_FAULTED);
> > > > +             dev_err(dev->dev, "%s: Preemption failed to complete\n",
> > > > +                     gpu->name);
> > > > +             kthread_queue_work(gpu->worker, &gpu->recover_work);
> > > > +             return;
> > > > +     }
> > > > +
> > > > +     a6xx_gpu->cur_ring = a6xx_gpu->next_ring;
> > > > +     a6xx_gpu->next_ring = NULL;
> > > > +
> > > > +     /* Make sure the write to cur_ring is posted before the change in state */
> > > > +     wmb();
> > > > +
> > > > +     set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
> > > > +
> > > > +     update_wptr(gpu, a6xx_gpu->cur_ring);
> > > > +
> > > > +     set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > > > +
> > > > +     /*
> > > > +      * Retrigger preemption to avoid a deadlock that might occur when preemption
> > > > +      * is skipped due to it being already in flight when requested.
> > > > +      */
> > > > +     a6xx_preempt_trigger(gpu);
> > > > +}
> > > > +
> > > > +void a6xx_preempt_hw_init(struct msm_gpu *gpu)
> > > > +{
> > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > +     int i;
> > > > +
> > > > +     /* No preemption if we only have one ring */
> > > > +     if (gpu->nr_rings == 1)
> > > > +             return;
> > > > +
> > > > +     for (i = 0; i < gpu->nr_rings; i++) {
> > > > +             struct a6xx_preempt_record *record_ptr =
> > > > +                     a6xx_gpu->preempt[i] + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > > > +             record_ptr->wptr = 0;
> > > > +             record_ptr->rptr = 0;
> > > > +             record_ptr->rptr_addr = shadowptr(a6xx_gpu, gpu->rb[i]);
> > > > +             record_ptr->info = 0;
> > > > +             record_ptr->data = 0;
> > > > +             record_ptr->rbase = gpu->rb[i]->iova;
> > > > +     }
> > > > +
> > > > +     /* Write a 0 to signal that we aren't switching pagetables */
> > > > +     gpu_write64(gpu, REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO, 0);
> > > > +
> > > > +     /* Enable the GMEM save/restore feature for preemption */
> > > > +     gpu_write(gpu, REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE, 0x1);
> > > > +
> > > > +     /* Reset the preemption state */
> > > > +     set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > > > +
> > > > +     spin_lock_init(&a6xx_gpu->eval_lock);
> > > > +
> > > > +     /* Always come up on rb 0 */
> > > > +     a6xx_gpu->cur_ring = gpu->rb[0];
> > > > +}
> > > > +
> > > > +void a6xx_preempt_trigger(struct msm_gpu *gpu)
> > > > +{
> > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > +     u64 preempt_offset_priv_secure;
> > > > +     unsigned long flags;
> > > > +     struct msm_ringbuffer *ring;
> > > > +     uint64_t user_ctx_iova;
> > > > +     unsigned int cntl;
> > > > +
> > > > +     if (gpu->nr_rings == 1)
> > > > +             return;
> > > > +
> > > > +     /*
> > > > +      * Lock to make sure another thread attempting preemption doesn't skip it
> > > > +      * while we are still evaluating the next ring. This makes sure the other
> > > > +      * thread does start preemption if we abort it and avoids a soft lock.
> > > > +      */
> > > > +     spin_lock_irqsave(&a6xx_gpu->eval_lock, flags);
> > > > +
> > > > +     /*
> > > > +      * Try to start preemption by moving from NONE to START. If
> > > > +      * unsuccessful, a preemption is already in flight
> > > > +      */
> > > > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_NONE, PREEMPT_START)) {
> > > > +             spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > > > +             return;
> > > > +     }
> > > > +
> > > > +     cntl = (((a6xx_gpu->preempt_level << 6) & 0xC0) |
> > > > +             ((a6xx_gpu->skip_save_restore << 9) & 0x200) |
> > > > +             ((a6xx_gpu->uses_gmem << 8) & 0x100) | 0x1);
> > > > +
> > > > +     /* Get the next ring to preempt to */
> > > > +     ring = get_next_ring(gpu);
> > > > +
> > > > +     /*
> > > > +      * If no ring is populated or the highest priority ring is the current
> > > > +      * one do nothing except to update the wptr to the latest and greatest
> > > > +      */
> > > > +     if (!ring || (a6xx_gpu->cur_ring == ring)) {
> > > > +             set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
> > > > +             update_wptr(gpu, a6xx_gpu->cur_ring);
> > > > +             set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > > > +             spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > > > +             return;
> > > > +     }
> > > > +
> > > > +     spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > > > +
> > > > +     spin_lock_irqsave(&ring->preempt_lock, flags);
> > > > +
> > > > +     struct a7xx_cp_smmu_info *smmu_info_ptr =
> > > > +             a6xx_gpu->preempt[ring->id] + PREEMPT_OFFSET_SMMU_INFO;
> > > > +     struct a6xx_preempt_record *record_ptr =
> > > > +             a6xx_gpu->preempt[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > > > +     u64 ttbr0 = ring->memptrs->ttbr0;
> > > > +     u32 context_idr = ring->memptrs->context_idr;
> > > > +
> > > > +     smmu_info_ptr->ttbr0 = ttbr0;
> > > > +     smmu_info_ptr->context_idr = context_idr;
> > > > +     record_ptr->wptr = get_wptr(ring);
> > > > +
> > > > +     /*
> > > > +      * The GPU will write the wptr we set above when we preempt. Reset
> > > > +      * skip_inline_wptr to make sure that we don't write WPTR to the same
> > > > +      * thing twice. It's still possible subsequent submissions will update
> > > > +      * wptr again, in which case they will set the flag to true. This has
> > > > +      * to be protected by the lock for setting the flag and updating wptr
> > > > +      * to be atomic.
> > > > +      */
> > > > +     ring->skip_inline_wptr = false;
> > > > +
> > > > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > > +
> > > > +     gpu_write64(gpu,
> > > > +             REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO,
> > > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_SMMU_INFO);
> > > > +
> > > > +     gpu_write64(gpu,
> > > > +             REG_A6XX_CP_CONTEXT_SWITCH_PRIV_NON_SECURE_RESTORE_ADDR,
> > > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE);
> > > > +
> > > > +     preempt_offset_priv_secure =
> > > > +             PREEMPT_OFFSET_PRIV_SECURE(adreno_gpu->info->preempt_record_size);
> > > > +     gpu_write64(gpu,
> > > > +             REG_A6XX_CP_CONTEXT_SWITCH_PRIV_SECURE_RESTORE_ADDR,
> > > > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure);
> > > > +
> > > > +     /*
> > > > +      * Use the user context iova from the scratch memory that the CP may
> > > > +      * have written as part of the ring switch out.
> > > > +      */
> > > > +     user_ctx_iova = *((uint64_t *)a6xx_gpu->scratch_ptr + ring->id);
> > > > +
> > > > +     gpu_write64(gpu,
> > > > +             REG_A6XX_CP_CONTEXT_SWITCH_NON_PRIV_RESTORE_ADDR,
> > > > +             user_ctx_iova);
> > > > +
> > > > +     a6xx_gpu->next_ring = ring;
> > > > +
> > > > +     /* Start a timer to catch a stuck preemption */
> > > > +     mod_timer(&a6xx_gpu->preempt_timer, jiffies + msecs_to_jiffies(10000));
> > > > +
> > > > +     /* Set the preemption state to triggered */
> > > > +     set_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED);
> > > > +
> > > > +     /* Make sure any previous writes to WPTR are posted */
> > > > +     gpu_read(gpu, REG_A6XX_CP_RB_WPTR);
> > > > +
> > > > +     /* Make sure everything is written before hitting the button */
> > > > +     wmb();
> > > > +
> > > > +     /* Trigger the preemption */
> > > > +     gpu_write(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL, cntl);
> > > > +}
> > > > +
> > > > +static int preempt_init_ring(struct a6xx_gpu *a6xx_gpu,
> > > > +             struct msm_ringbuffer *ring)
> > > > +{
> > > > +     struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
> > > > +     struct msm_gpu *gpu = &adreno_gpu->base;
> > > > +     struct drm_gem_object *bo = NULL;
> > > > +     phys_addr_t ttbr;
> > > > +     u64 iova = 0;
> > > > +     void *ptr;
> > > > +     int asid;
> > > > +
> > > > +     ptr = msm_gem_kernel_new(gpu->dev,
> > > > +             PREEMPT_SIZE(adreno_gpu->info->preempt_record_size),
> > > > +             MSM_BO_WC | MSM_BO_MAP_PRIV, gpu->aspace, &bo, &iova);
> > > > +
> > > > +     memset(ptr, 0, PREEMPT_SIZE(adreno_gpu->info->preempt_record_size));
> > > > +
> > > > +     if (IS_ERR(ptr))
> > > > +             return PTR_ERR(ptr);
> > > > +
> > > > +     a6xx_gpu->preempt_bo[ring->id] = bo;
> > > > +     a6xx_gpu->preempt_iova[ring->id] = iova;
> > > > +     a6xx_gpu->preempt[ring->id] = ptr;
> > > > +
> > > > +     struct a7xx_cp_smmu_info *smmu_info_ptr = ptr + PREEMPT_OFFSET_SMMU_INFO;
> > > > +     struct a6xx_preempt_record *record_ptr = ptr + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > > > +
> > > > +     msm_iommu_pagetable_params(gpu->aspace->mmu, &ttbr, &asid);
> > > > +
> > > > +     smmu_info_ptr->magic = GEN7_CP_SMMU_INFO_MAGIC;
> > > > +     smmu_info_ptr->ttbr0 = ttbr;
> > > > +     smmu_info_ptr->asid = 0xdecafbad;
> > > > +     smmu_info_ptr->context_idr = 0;
> > > > +
> > > > +     /* Set up the defaults on the preemption record */
> > > > +     record_ptr->magic = A6XX_PREEMPT_RECORD_MAGIC;
> > > > +     record_ptr->info = 0;
> > > > +     record_ptr->data = 0;
> > > > +     record_ptr->rptr = 0;
> > > > +     record_ptr->wptr = 0;
> > > > +     record_ptr->cntl = MSM_GPU_RB_CNTL_DEFAULT;
> > > > +     record_ptr->rbase = ring->iova;
> > > > +     record_ptr->counter = 0;
> > > > +     record_ptr->bv_rptr_addr = rbmemptr(ring, bv_rptr);
> > > > +
> > > > +     return 0;
> > > > +}
> > > > +
> > > > +void a6xx_preempt_fini(struct msm_gpu *gpu)
> > > > +{
> > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > +     int i;
> > > > +
> > > > +     for (i = 0; i < gpu->nr_rings; i++)
> > > > +             msm_gem_kernel_put(a6xx_gpu->preempt_bo[i], gpu->aspace);
> > > > +}
> > > > +
> > > > +void a6xx_preempt_init(struct msm_gpu *gpu)
> > > > +{
> > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > +     int i;
> > > > +
> > > > +     /* No preemption if we only have one ring */
> > > > +     if (gpu->nr_rings <= 1)
> > > > +             return;
> > > > +
> > > > +     for (i = 0; i < gpu->nr_rings; i++) {
> > > > +             if (preempt_init_ring(a6xx_gpu, gpu->rb[i]))
> > > > +                     goto fail;
> > > > +     }
> > > > +
> > > > +     /* TODO: make this configurable? */
> > > > +     a6xx_gpu->preempt_level = 1;
> > > > +     a6xx_gpu->uses_gmem = 1;
> > > > +     a6xx_gpu->skip_save_restore = 1;
> > > > +
> > > > +     a6xx_gpu->scratch_ptr  = msm_gem_kernel_new(gpu->dev,
> > > > +                     gpu->nr_rings * sizeof(uint64_t), MSM_BO_WC,
> > > > +                     gpu->aspace, &a6xx_gpu->scratch_bo,
> > > > +                     &a6xx_gpu->scratch_iova);
> > > > +
> > > > +     if (IS_ERR(a6xx_gpu->scratch_ptr))
> > > > +             goto fail;
> > > > +
> > > > +     timer_setup(&a6xx_gpu->preempt_timer, a6xx_preempt_timer, 0);
> > > > +
> > > > +     return;
> > > > +fail:
> > > > +     /*
> > > > +      * On any failure our adventure is over. Clean up and
> > > > +      * set nr_rings to 1 to force preemption off
> > > > +      */
> > > > +     a6xx_preempt_fini(gpu);
> > > > +     gpu->nr_rings = 1;
> > > > +
> > > > +     return;
> > > > +}
> > > > +
> > > > +void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
> > > > +             struct msm_gpu_submitqueue *queue)
> > > > +{
> > > > +     if (!queue->bo)
> > > > +             return;
> > > > +
> > > > +     msm_gem_kernel_put(queue->bo, gpu->aspace);
> > > > +}
> > > > +
> > > > +int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
> > > > +             struct msm_gpu_submitqueue *queue)
> > > > +{
> > > > +     void *ptr;
> > > > +
> > > > +     /*
> > > > +      * Create a per submitqueue buffer for the CP to save and restore user
> > > > +      * specific information such as the VPC streamout data.
> > > > +      */
> > > > +     ptr = msm_gem_kernel_new(gpu->dev, A6XX_PREEMPT_USER_RECORD_SIZE,
> > > > +                     MSM_BO_WC, gpu->aspace, &queue->bo, &queue->bo_iova);
> > > > +
> > > > +     if (IS_ERR(ptr))
> > > > +             return PTR_ERR(ptr);
> > > > +
> > > > +     return 0;
> > > > +}
> > > > diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.h b/drivers/gpu/drm/msm/msm_ringbuffer.h
> > > > index 40791b2ade46..7dde6a312511 100644
> > > > --- a/drivers/gpu/drm/msm/msm_ringbuffer.h
> > > > +++ b/drivers/gpu/drm/msm/msm_ringbuffer.h
> > > > @@ -36,6 +36,7 @@ struct msm_rbmemptrs {
> > > >
> > > >       volatile struct msm_gpu_submit_stats stats[MSM_GPU_SUBMIT_STATS_COUNT];
> > > >       volatile u64 ttbr0;
> > > > +     volatile u32 context_idr;
> > > >  };
> > > >
> > > >  struct msm_cp_state {
> > > > @@ -100,6 +101,12 @@ struct msm_ringbuffer {
> > > >        * preemption.  Can be aquired from irq context.
> > > >        */
> > > >       spinlock_t preempt_lock;
> > > > +
> > > > +     /*
> > > > +      * Whether we skipped writing wptr and it needs to be updated in the
> > > > +      * future when the ring becomes current.
> > > > +      */
> > > > +     bool skip_inline_wptr;
> > > >  };
> > > >
> > > >  struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int id,
> > > >
> > > > --
> > > > 2.46.0
> > > >
> > > >

Connor Abbott Aug. 23, 2024, 9:23 a.m. UTC | #10

On Fri, Aug 23, 2024 at 10:21 AM Connor Abbott <[e-mail]> wrote:
>
> On Thu, Aug 22, 2024 at 9:06 PM Akhil P Oommen <[e-mail]> wrote:
> >
> > On Wed, Aug 21, 2024 at 05:02:56PM +0100, Connor Abbott wrote:
> > > On Mon, Aug 19, 2024 at 9:09 PM Akhil P Oommen <[e-mail]> wrote:
> > > >
> > > > On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
> > > > > This patch implements preemption feature for A6xx targets, this allows
> > > > > the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
> > > > > hardware as such supports multiple levels of preemption granularities,
> > > > > ranging from coarse grained(ringbuffer level) to a more fine grained
> > > > > such as draw-call level or a bin boundary level preemption. This patch
> > > > > enables the basic preemption level, with more fine grained preemption
> > > > > support to follow.
> > > > >
> > > > > Signed-off-by: Sharat Masetty <[e-mail]>
> > > > > Signed-off-by: Antonino Maniscalco <[e-mail]>
> > > > > ---
> > > >
> > > > No postamble packets which resets perfcounters? It is necessary. Also, I
> > > > think we should disable preemption during profiling like we disable slumber.
> > > >
> > > > -Akhil.
> > >
> > > I don't see anything in kgsl which disables preemption during
> > > profiling. It disables resetting perfcounters when doing system-wide
> > > profiling, like freedreno, and in that case I assume preempting is
> > > fine because the system profiler has a complete view of everything and
> > > should "see" preemptions through the traces. For something like
> > > VK_KHR_performance_query I suppose we'd want to disable preemption
> > > because we disable saving/restoring perf counters, but that has to
> > > happen in userspace because the kernel doesn't know what userspace
> > > does.
> > >
> >
> > KGSL does some sort of arbitration of perfcounter configurations and
> > adds the select/enablement reg configuration as part of dynamic
> > power up register list which we are not doing here. Is this something
> > you are taking care of from userspace via preamble?
> >
> > -Akhil
>
> I don't think we have to take care of that in userspace, because Mesa
> will always configure the counter registers before reading them in the
> same submission, and if it gets preempted in the meantime then we're
> toast anyways (due to not saving/restoring perf counters). kgsl sets
> them from userspace, which is why it has to do something to set them

Sorry, should be "kgsl sets them from the kernel".

> after IFPC slumber or a context switch when the HW state is gone.
> Also, because the upstream approach doesn't play nicely with system
> profilers like perfetto, VK_KHR_performance_query is hidden by default
> behind a debug flag in turnip. So there's already an element of "this
> is unsupported, you have to know what you're doing to use it."
>
> Connor
>
> >
> > > Connor
> > >
> > > >
> > > > >  drivers/gpu/drm/msm/Makefile              |   1 +
> > > > >  drivers/gpu/drm/msm/adreno/a6xx_gpu.c     | 323 +++++++++++++++++++++-
> > > > >  drivers/gpu/drm/msm/adreno/a6xx_gpu.h     | 168 ++++++++++++
> > > > >  drivers/gpu/drm/msm/adreno/a6xx_preempt.c | 434 ++++++++++++++++++++++++++++++
> > > > >  drivers/gpu/drm/msm/msm_ringbuffer.h      |   7 +
> > > > >  5 files changed, 924 insertions(+), 9 deletions(-)
> > > > >
> > > > > diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile
> > > > > index f5e2838c6a76..32e915109a59 100644
> > > > > --- a/drivers/gpu/drm/msm/Makefile
> > > > > +++ b/drivers/gpu/drm/msm/Makefile
> > > > > @@ -23,6 +23,7 @@ adreno-y := \
> > > > >       adreno/a6xx_gpu.o \
> > > > >       adreno/a6xx_gmu.o \
> > > > >       adreno/a6xx_hfi.o \
> > > > > +     adreno/a6xx_preempt.o \
> > > > >
> > > > >  adreno-$(CONFIG_DEBUG_FS) += adreno/a5xx_debugfs.o \
> > > > >
> > > > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > > > index 32a4faa93d7f..1a90db5759b8 100644
> > > > > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > > > @@ -16,6 +16,83 @@
> > > > >
> > > > >  #define GPU_PAS_ID 13
> > > > >
> > > > > +/* IFPC & Preemption static powerup restore list */
> > > > > +static const uint32_t a7xx_pwrup_reglist[] = {
> > > > > +     REG_A6XX_UCHE_TRAP_BASE,
> > > > > +     REG_A6XX_UCHE_TRAP_BASE + 1,
> > > > > +     REG_A6XX_UCHE_WRITE_THRU_BASE,
> > > > > +     REG_A6XX_UCHE_WRITE_THRU_BASE + 1,
> > > > > +     REG_A6XX_UCHE_GMEM_RANGE_MIN,
> > > > > +     REG_A6XX_UCHE_GMEM_RANGE_MIN + 1,
> > > > > +     REG_A6XX_UCHE_GMEM_RANGE_MAX,
> > > > > +     REG_A6XX_UCHE_GMEM_RANGE_MAX + 1,
> > > > > +     REG_A6XX_UCHE_CACHE_WAYS,
> > > > > +     REG_A6XX_UCHE_MODE_CNTL,
> > > > > +     REG_A6XX_RB_NC_MODE_CNTL,
> > > > > +     REG_A6XX_RB_CMP_DBG_ECO_CNTL,
> > > > > +     REG_A7XX_GRAS_NC_MODE_CNTL,
> > > > > +     REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE,
> > > > > +     REG_A6XX_UCHE_GBIF_GX_CONFIG,
> > > > > +     REG_A6XX_UCHE_CLIENT_PF,
> > > > > +};
> > > > > +
> > > > > +static const uint32_t a7xx_ifpc_pwrup_reglist[] = {
> > > > > +     REG_A6XX_TPL1_NC_MODE_CNTL,
> > > > > +     REG_A6XX_SP_NC_MODE_CNTL,
> > > > > +     REG_A6XX_CP_DBG_ECO_CNTL,
> > > > > +     REG_A6XX_CP_PROTECT_CNTL,
> > > > > +     REG_A6XX_CP_PROTECT(0),
> > > > > +     REG_A6XX_CP_PROTECT(1),
> > > > > +     REG_A6XX_CP_PROTECT(2),
> > > > > +     REG_A6XX_CP_PROTECT(3),
> > > > > +     REG_A6XX_CP_PROTECT(4),
> > > > > +     REG_A6XX_CP_PROTECT(5),
> > > > > +     REG_A6XX_CP_PROTECT(6),
> > > > > +     REG_A6XX_CP_PROTECT(7),
> > > > > +     REG_A6XX_CP_PROTECT(8),
> > > > > +     REG_A6XX_CP_PROTECT(9),
> > > > > +     REG_A6XX_CP_PROTECT(10),
> > > > > +     REG_A6XX_CP_PROTECT(11),
> > > > > +     REG_A6XX_CP_PROTECT(12),
> > > > > +     REG_A6XX_CP_PROTECT(13),
> > > > > +     REG_A6XX_CP_PROTECT(14),
> > > > > +     REG_A6XX_CP_PROTECT(15),
> > > > > +     REG_A6XX_CP_PROTECT(16),
> > > > > +     REG_A6XX_CP_PROTECT(17),
> > > > > +     REG_A6XX_CP_PROTECT(18),
> > > > > +     REG_A6XX_CP_PROTECT(19),
> > > > > +     REG_A6XX_CP_PROTECT(20),
> > > > > +     REG_A6XX_CP_PROTECT(21),
> > > > > +     REG_A6XX_CP_PROTECT(22),
> > > > > +     REG_A6XX_CP_PROTECT(23),
> > > > > +     REG_A6XX_CP_PROTECT(24),
> > > > > +     REG_A6XX_CP_PROTECT(25),
> > > > > +     REG_A6XX_CP_PROTECT(26),
> > > > > +     REG_A6XX_CP_PROTECT(27),
> > > > > +     REG_A6XX_CP_PROTECT(28),
> > > > > +     REG_A6XX_CP_PROTECT(29),
> > > > > +     REG_A6XX_CP_PROTECT(30),
> > > > > +     REG_A6XX_CP_PROTECT(31),
> > > > > +     REG_A6XX_CP_PROTECT(32),
> > > > > +     REG_A6XX_CP_PROTECT(33),
> > > > > +     REG_A6XX_CP_PROTECT(34),
> > > > > +     REG_A6XX_CP_PROTECT(35),
> > > > > +     REG_A6XX_CP_PROTECT(36),
> > > > > +     REG_A6XX_CP_PROTECT(37),
> > > > > +     REG_A6XX_CP_PROTECT(38),
> > > > > +     REG_A6XX_CP_PROTECT(39),
> > > > > +     REG_A6XX_CP_PROTECT(40),
> > > > > +     REG_A6XX_CP_PROTECT(41),
> > > > > +     REG_A6XX_CP_PROTECT(42),
> > > > > +     REG_A6XX_CP_PROTECT(43),
> > > > > +     REG_A6XX_CP_PROTECT(44),
> > > > > +     REG_A6XX_CP_PROTECT(45),
> > > > > +     REG_A6XX_CP_PROTECT(46),
> > > > > +     REG_A6XX_CP_PROTECT(47),
> > > > > +     REG_A6XX_CP_AHB_CNTL,
> > > > > +};
> > > > > +
> > > > > +
> > > > >  static inline bool _a6xx_check_idle(struct msm_gpu *gpu)
> > > > >  {
> > > > >       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > @@ -68,6 +145,8 @@ static void update_shadow_rptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > > > >
> > > > >  static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > > > >  {
> > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > >       uint32_t wptr;
> > > > >       unsigned long flags;
> > > > >
> > > > > @@ -81,12 +160,26 @@ static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > > > >       /* Make sure to wrap wptr if we need to */
> > > > >       wptr = get_wptr(ring);
> > > > >
> > > > > -     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > > > -
> > > > >       /* Make sure everything is posted before making a decision */
> > > > >       mb();
> > > > >
> > > > > -     gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > > > > +     /* Update HW if this is the current ring and we are not in preempt*/
> > > > > +     if (!a6xx_in_preempt(a6xx_gpu)) {
> > > > > +             /*
> > > > > +              * Order the reads of the preempt state and cur_ring. This
> > > > > +              * matches the barrier after writing cur_ring.
> > > > > +              */
> > > > > +             rmb();
> > > > > +
> > > > > +             if (a6xx_gpu->cur_ring == ring)
> > > > > +                     gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > > > > +             else
> > > > > +                     ring->skip_inline_wptr = true;
> > > > > +     } else {
> > > > > +             ring->skip_inline_wptr = true;
> > > > > +     }
> > > > > +
> > > > > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > > >  }
> > > > >
> > > > >  static void get_stats_counter(struct msm_ringbuffer *ring, u32 counter,
> > > > > @@ -138,12 +231,14 @@ static void a6xx_set_pagetable(struct a6xx_gpu *a6xx_gpu,
> > > > >
> > > > >       /*
> > > > >        * Write the new TTBR0 to the memstore. This is good for debugging.
> > > > > +      * Needed for preemption
> > > > >        */
> > > > > -     OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > > > > +     OUT_PKT7(ring, CP_MEM_WRITE, 5);
> > > > >       OUT_RING(ring, CP_MEM_WRITE_0_ADDR_LO(lower_32_bits(memptr)));
> > > > >       OUT_RING(ring, CP_MEM_WRITE_1_ADDR_HI(upper_32_bits(memptr)));
> > > > >       OUT_RING(ring, lower_32_bits(ttbr));
> > > > > -     OUT_RING(ring, (asid << 16) | upper_32_bits(ttbr));
> > > > > +     OUT_RING(ring, upper_32_bits(ttbr));
> > > > > +     OUT_RING(ring, ctx->seqno);
> > > > >
> > > > >       /*
> > > > >        * Sync both threads after switching pagetables and enable BR only
> > > > > @@ -268,12 +363,55 @@ static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > > >       a6xx_flush(gpu, ring);
> > > > >  }
> > > > >
> > > > > +static void a6xx_emit_set_pseudo_reg(struct msm_ringbuffer *ring,
> > > > > +             struct a6xx_gpu *a6xx_gpu, struct msm_gpu_submitqueue *queue)
> > > > > +{
> > > > > +     u64 preempt_offset_priv_secure;
> > > > > +
> > > > > +     OUT_PKT7(ring, CP_SET_PSEUDO_REG, 15);
> > > > > +
> > > > > +     OUT_RING(ring, SMMU_INFO);
> > > > > +     /* don't save SMMU, we write the record from the kernel instead */
> > > > > +     OUT_RING(ring, 0);
> > > > > +     OUT_RING(ring, 0);
> > > > > +
> > > > > +     /* privileged and non secure buffer save */
> > > > > +     OUT_RING(ring, NON_SECURE_SAVE_ADDR);
> > > > > +     OUT_RING(ring, lower_32_bits(
> > > > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE));
> > > > > +     OUT_RING(ring, upper_32_bits(
> > > > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE));
> > > > > +     OUT_RING(ring, SECURE_SAVE_ADDR);
> > > > > +     preempt_offset_priv_secure =
> > > > > +             PREEMPT_OFFSET_PRIV_SECURE(a6xx_gpu->base.info->preempt_record_size);
> > > > > +     OUT_RING(ring, lower_32_bits(
> > > > > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure));
> > > > > +     OUT_RING(ring, upper_32_bits(
> > > > > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure));
> > > > > +
> > > > > +     /* user context buffer save */
> > > > > +     OUT_RING(ring, NON_PRIV_SAVE_ADDR);
> > > > > +     if (queue) {
> > > > > +             OUT_RING(ring, lower_32_bits(queue->bo_iova));
> > > > > +             OUT_RING(ring, upper_32_bits(queue->bo_iova));
> > > > > +     } else {
> > > > > +             OUT_RING(ring, 0);
> > > > > +             OUT_RING(ring, 0);
> > > > > +     }
> > > > > +
> > > > > +     OUT_RING(ring, COUNTER);
> > > > > +     /* seems OK to set to 0 to disable it */
> > > > > +     OUT_RING(ring, 0);
> > > > > +     OUT_RING(ring, 0);
> > > > > +}
> > > > > +
> > > > >  static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > > >  {
> > > > >       unsigned int index = submit->seqno % MSM_GPU_SUBMIT_STATS_COUNT;
> > > > >       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > >       struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > >       struct msm_ringbuffer *ring = submit->ring;
> > > > > +     uint64_t scratch_dest = SCRATCH_USER_CTX_IOVA(ring->id, a6xx_gpu);
> > > > >       unsigned int i, ibs = 0;
> > > > >
> > > > >       /*
> > > > > @@ -283,6 +421,25 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > > >       OUT_PKT7(ring, CP_THREAD_CONTROL, 1);
> > > > >       OUT_RING(ring, CP_THREAD_CONTROL_0_SYNC_THREADS | CP_SET_THREAD_BR);
> > > > >
> > > > > +     /*
> > > > > +      * If preemption is enabled, then set the pseudo register for the save
> > > > > +      * sequence
> > > > > +      */
> > > > > +     if (gpu->nr_rings > 1) {
> > > > > +             a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, submit->queue);
> > > > > +
> > > > > +             /*
> > > > > +              * Ask CP to save the user context buffer's iova address to a
> > > > > +              * scratch memory region, this is needed if the CP preempts
> > > > > +              * this ring in between this submit's IB list.
> > > > > +              */
> > > > > +             OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > > > > +             OUT_RING(ring, lower_32_bits(scratch_dest));
> > > > > +             OUT_RING(ring, upper_32_bits(scratch_dest));
> > > > > +             OUT_RING(ring, lower_32_bits(submit->queue->bo_iova));
> > > > > +             OUT_RING(ring, upper_32_bits(submit->queue->bo_iova));
> > > > > +     }
> > > > > +
> > > > >       a6xx_set_pagetable(a6xx_gpu, ring, submit->queue->ctx);
> > > > >
> > > > >       get_stats_counter(ring, REG_A7XX_RBBM_PERFCTR_CP(0),
> > > > > @@ -376,6 +533,8 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > > >       OUT_RING(ring, upper_32_bits(rbmemptr(ring, bv_fence)));
> > > > >       OUT_RING(ring, submit->seqno);
> > > > >
> > > > > +     a6xx_gpu->last_seqno[ring->id] = submit->seqno;
> > > > > +
> > > > >       /* write the ringbuffer timestamp */
> > > > >       OUT_PKT7(ring, CP_EVENT_WRITE, 4);
> > > > >       OUT_RING(ring, CACHE_CLEAN | CP_EVENT_WRITE_0_IRQ | BIT(27));
> > > > > @@ -389,10 +548,42 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > > >       OUT_PKT7(ring, CP_SET_MARKER, 1);
> > > > >       OUT_RING(ring, 0x100); /* IFPC enable */
> > > > >
> > > > > +     /* If preemption is enabled */
> > > > > +     if (gpu->nr_rings > 1) {
> > > > > +             /*
> > > > > +              * Reset the scratch region as we are done with the
> > > > > +              * IB list of this submission
> > > > > +              */
> > > > > +             OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > > > > +             OUT_RING(ring, lower_32_bits(scratch_dest));
> > > > > +             OUT_RING(ring, upper_32_bits(scratch_dest));
> > > > > +             OUT_RING(ring, 0x00);
> > > > > +             OUT_RING(ring, 0x00);
> > > > > +
> > > > > +             /* Yield the floor on command completion */
> > > > > +             OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
> > > > > +
> > > > > +             /*
> > > > > +              * If dword[2:1] are non zero, they specify an address for
> > > > > +              * the CP to write the value of dword[3] to on preemption
> > > > > +              * complete. Write 0 to skip the write
> > > > > +              */
> > > > > +             OUT_RING(ring, 0x00);
> > > > > +             OUT_RING(ring, 0x00);
> > > > > +             /* Data value - not used if the address above is 0 */
> > > > > +             OUT_RING(ring, 0x01);
> > > > > +             /* generate interrupt on preemption completion */
> > > > > +             OUT_RING(ring, 0x00);
> > > > > +     }
> > > > > +
> > > > > +
> > > > >       trace_msm_gpu_submit_flush(submit,
> > > > >               gpu_read64(gpu, REG_A6XX_CP_ALWAYS_ON_COUNTER));
> > > > >
> > > > >       a6xx_flush(gpu, ring);
> > > > > +
> > > > > +     /* Check to see if we need to start preemption */
> > > > > +     a6xx_preempt_trigger(gpu);
> > > > >  }
> > > > >
> > > > >  static void a6xx_set_hwcg(struct msm_gpu *gpu, bool state)
> > > > > @@ -588,6 +779,89 @@ static void a6xx_set_ubwc_config(struct msm_gpu *gpu)
> > > > >                 adreno_gpu->ubwc_config.min_acc_len << 23 | hbb_lo << 21);
> > > > >  }
> > > > >
> > > > > +static void a7xx_patch_pwrup_reglist(struct msm_gpu *gpu)
> > > > > +{
> > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > +     struct adreno_reglist_list reglist[2];
> > > > > +     void *ptr = a6xx_gpu->pwrup_reglist_ptr;
> > > > > +     struct cpu_gpu_lock *lock = ptr;
> > > > > +     u32 *dest = (u32 *)&lock->regs[0];
> > > > > +     int i, j;
> > > > > +
> > > > > +     lock->gpu_req = lock->cpu_req = lock->turn = 0;
> > > > > +     lock->ifpc_list_len = ARRAY_SIZE(a7xx_ifpc_pwrup_reglist);
> > > > > +     lock->preemption_list_len = ARRAY_SIZE(a7xx_pwrup_reglist);
> > > > > +
> > > > > +     /* Static IFPC-only registers */
> > > > > +     reglist[0].regs = a7xx_ifpc_pwrup_reglist;
> > > > > +     reglist[0].count = ARRAY_SIZE(a7xx_ifpc_pwrup_reglist);
> > > > > +     lock->ifpc_list_len = reglist[0].count;
> > > > > +
> > > > > +     /* Static IFPC + preemption registers */
> > > > > +     reglist[1].regs = a7xx_pwrup_reglist;
> > > > > +     reglist[1].count = ARRAY_SIZE(a7xx_pwrup_reglist);
> > > > > +     lock->preemption_list_len = reglist[1].count;
> > > > > +
> > > > > +     /*
> > > > > +      * For each entry in each of the lists, write the offset and the current
> > > > > +      * register value into the GPU buffer
> > > > > +      */
> > > > > +     for (i = 0; i < 2; i++) {
> > > > > +             const u32 *r = reglist[i].regs;
> > > > > +
> > > > > +             for (j = 0; j < reglist[i].count; j++) {
> > > > > +                     *dest++ = r[j];
> > > > > +                     *dest++ = gpu_read(gpu, r[j]);
> > > > > +             }
> > > > > +     }
> > > > > +
> > > > > +     /*
> > > > > +      * The overall register list is composed of
> > > > > +      * 1. Static IFPC-only registers
> > > > > +      * 2. Static IFPC + preemption registers
> > > > > +      * 3. Dynamic IFPC + preemption registers (ex: perfcounter selects)
> > > > > +      *
> > > > > +      * The first two lists are static. Size of these lists are stored as
> > > > > +      * number of pairs in ifpc_list_len and preemption_list_len
> > > > > +      * respectively. With concurrent binning, Some of the perfcounter
> > > > > +      * registers being virtualized, CP needs to know the pipe id to program
> > > > > +      * the aperture inorder to restore the same. Thus, third list is a
> > > > > +      * dynamic list with triplets as
> > > > > +      * (<aperture, shifted 12 bits> <address> <data>), and the length is
> > > > > +      * stored as number for triplets in dynamic_list_len.
> > > > > +      */
> > > > > +     lock->dynamic_list_len = 0;
> > > > > +}
> > > > > +
> > > > > +static int a7xx_preempt_start(struct msm_gpu *gpu)
> > > > > +{
> > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > +     struct msm_ringbuffer *ring = gpu->rb[0];
> > > > > +
> > > > > +     if (gpu->nr_rings <= 1)
> > > > > +             return 0;
> > > > > +
> > > > > +     /* Turn CP protection off */
> > > > > +     OUT_PKT7(ring, CP_SET_PROTECTED_MODE, 1);
> > > > > +     OUT_RING(ring, 0);
> > > > > +
> > > > > +     a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, NULL);
> > > > > +
> > > > > +     /* Yield the floor on command completion */
> > > > > +     OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
> > > > > +     OUT_RING(ring, 0x00);
> > > > > +     OUT_RING(ring, 0x00);
> > > > > +     OUT_RING(ring, 0x01);
> > > > > +     /* Generate interrupt on preemption completion */
> > > > > +     OUT_RING(ring, 0x00);
> > > > > +
> > > > > +     a6xx_flush(gpu, ring);
> > > > > +
> > > > > +     return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
> > > > > +}
> > > > > +
> > > > >  static int a6xx_cp_init(struct msm_gpu *gpu)
> > > > >  {
> > > > >       struct msm_ringbuffer *ring = gpu->rb[0];
> > > > > @@ -619,6 +893,8 @@ static int a6xx_cp_init(struct msm_gpu *gpu)
> > > > >
> > > > >  static int a7xx_cp_init(struct msm_gpu *gpu)
> > > > >  {
> > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > >       struct msm_ringbuffer *ring = gpu->rb[0];
> > > > >       u32 mask;
> > > > >
> > > > > @@ -626,6 +902,8 @@ static int a7xx_cp_init(struct msm_gpu *gpu)
> > > > >       OUT_PKT7(ring, CP_THREAD_CONTROL, 1);
> > > > >       OUT_RING(ring, BIT(27));
> > > > >
> > > > > +     a7xx_patch_pwrup_reglist(gpu);
> > > > > +
> > > > >       OUT_PKT7(ring, CP_ME_INIT, 7);
> > > > >
> > > > >       /* Use multiple HW contexts */
> > > > > @@ -656,11 +934,11 @@ static int a7xx_cp_init(struct msm_gpu *gpu)
> > > > >
> > > > >       /* *Don't* send a power up reg list for concurrent binning (TODO) */
> > > > >       /* Lo address */
> > > > > -     OUT_RING(ring, 0x00000000);
> > > > > +     OUT_RING(ring, lower_32_bits(a6xx_gpu->pwrup_reglist_iova));
> > > > >       /* Hi address */
> > > > > -     OUT_RING(ring, 0x00000000);
> > > > > +     OUT_RING(ring, upper_32_bits(a6xx_gpu->pwrup_reglist_iova));
> > > > >       /* BIT(31) set => read the regs from the list */
> > > > > -     OUT_RING(ring, 0x00000000);
> > > > > +     OUT_RING(ring, BIT(31));
> > > > >
> > > > >       a6xx_flush(gpu, ring);
> > > > >       return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
> > > > > @@ -784,6 +1062,16 @@ static int a6xx_ucode_load(struct msm_gpu *gpu)
> > > > >               msm_gem_object_set_name(a6xx_gpu->shadow_bo, "shadow");
> > > > >       }
> > > > >
> > > > > +     a6xx_gpu->pwrup_reglist_ptr = msm_gem_kernel_new(gpu->dev, PAGE_SIZE,
> > > > > +                                                      MSM_BO_WC  | MSM_BO_MAP_PRIV,
> > > > > +                                                      gpu->aspace, &a6xx_gpu->pwrup_reglist_bo,
> > > > > +                                                      &a6xx_gpu->pwrup_reglist_iova);
> > > > > +
> > > > > +     if (IS_ERR(a6xx_gpu->pwrup_reglist_ptr))
> > > > > +             return PTR_ERR(a6xx_gpu->pwrup_reglist_ptr);
> > > > > +
> > > > > +     msm_gem_object_set_name(a6xx_gpu->pwrup_reglist_bo, "pwrup_reglist");
> > > > > +
> > > > >       return 0;
> > > > >  }
> > > > >
> > > > > @@ -1127,6 +1415,8 @@ static int hw_init(struct msm_gpu *gpu)
> > > > >       if (a6xx_gpu->shadow_bo) {
> > > > >               gpu_write64(gpu, REG_A6XX_CP_RB_RPTR_ADDR,
> > > > >                       shadowptr(a6xx_gpu, gpu->rb[0]));
> > > > > +             for (unsigned int i = 0; i < gpu->nr_rings; i++)
> > > > > +                     a6xx_gpu->shadow[i] = 0;
> > > > >       }
> > > > >
> > > > >       /* ..which means "always" on A7xx, also for BV shadow */
> > > > > @@ -1135,6 +1425,8 @@ static int hw_init(struct msm_gpu *gpu)
> > > > >                           rbmemptr(gpu->rb[0], bv_rptr));
> > > > >       }
> > > > >
> > > > > +     a6xx_preempt_hw_init(gpu);
> > > > > +
> > > > >       /* Always come up on rb 0 */
> > > > >       a6xx_gpu->cur_ring = gpu->rb[0];
> > > > >
> > > > > @@ -1180,6 +1472,10 @@ static int hw_init(struct msm_gpu *gpu)
> > > > >  out:
> > > > >       if (adreno_has_gmu_wrapper(adreno_gpu))
> > > > >               return ret;
> > > > > +
> > > > > +     /* Last step - yield the ringbuffer */
> > > > > +     a7xx_preempt_start(gpu);
> > > > > +
> > > > >       /*
> > > > >        * Tell the GMU that we are done touching the GPU and it can start power
> > > > >        * management
> > > > > @@ -1557,8 +1853,13 @@ static irqreturn_t a6xx_irq(struct msm_gpu *gpu)
> > > > >       if (status & A6XX_RBBM_INT_0_MASK_SWFUSEVIOLATION)
> > > > >               a7xx_sw_fuse_violation_irq(gpu);
> > > > >
> > > > > -     if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS)
> > > > > +     if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS) {
> > > > >               msm_gpu_retire(gpu);
> > > > > +             a6xx_preempt_trigger(gpu);
> > > > > +     }
> > > > > +
> > > > > +     if (status & A6XX_RBBM_INT_0_MASK_CP_SW)
> > > > > +             a6xx_preempt_irq(gpu);
> > > > >
> > > > >       return IRQ_HANDLED;
> > > > >  }
> > > > > @@ -2165,6 +2466,8 @@ static const struct adreno_gpu_funcs funcs = {
> > > > >               .active_ring = a6xx_active_ring,
> > > > >               .irq = a6xx_irq,
> > > > >               .destroy = a6xx_destroy,
> > > > > +             .submitqueue_setup = a6xx_preempt_submitqueue_setup,
> > > > > +             .submitqueue_close = a6xx_preempt_submitqueue_close,
> > > > >  #if defined(CONFIG_DRM_MSM_GPU_STATE)
> > > > >               .show = a6xx_show,
> > > > >  #endif
> > > > > @@ -2331,6 +2634,8 @@ struct msm_gpu *a6xx_gpu_init(struct drm_device *dev)
> > > > >                               a6xx_fault_handler);
> > > > >
> > > > >       a6xx_calc_ubwc_config(adreno_gpu);
> > > > > +     /* Set up the preemption specific bits and pieces for each ringbuffer */
> > > > > +     a6xx_preempt_init(gpu);
> > > > >
> > > > >       return gpu;
> > > > >  }
> > > > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > > > > index e3e5c53ae8af..652e49f01428 100644
> > > > > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > > > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > > > > @@ -12,6 +12,31 @@
> > > > >
> > > > >  extern bool hang_debug;
> > > > >
> > > > > +struct cpu_gpu_lock {
> > > > > +     uint32_t gpu_req;
> > > > > +     uint32_t cpu_req;
> > > > > +     uint32_t turn;
> > > > > +     union {
> > > > > +             struct {
> > > > > +                     uint16_t list_length;
> > > > > +                     uint16_t list_offset;
> > > > > +             };
> > > > > +             struct {
> > > > > +                     uint8_t ifpc_list_len;
> > > > > +                     uint8_t preemption_list_len;
> > > > > +                     uint16_t dynamic_list_len;
> > > > > +             };
> > > > > +     };
> > > > > +     uint64_t regs[62];
> > > > > +};
> > > > > +
> > > > > +struct adreno_reglist_list {
> > > > > +     /** @reg: List of register **/
> > > > > +     const u32 *regs;
> > > > > +     /** @count: Number of registers in the list **/
> > > > > +     u32 count;
> > > > > +};
> > > > > +
> > > > >  /**
> > > > >   * struct a6xx_info - a6xx specific information from device table
> > > > >   *
> > > > > @@ -31,6 +56,24 @@ struct a6xx_gpu {
> > > > >       uint64_t sqe_iova;
> > > > >
> > > > >       struct msm_ringbuffer *cur_ring;
> > > > > +     struct msm_ringbuffer *next_ring;
> > > > > +
> > > > > +     struct drm_gem_object *preempt_bo[MSM_GPU_MAX_RINGS];
> > > > > +     void *preempt[MSM_GPU_MAX_RINGS];
> > > > > +     uint64_t preempt_iova[MSM_GPU_MAX_RINGS];
> > > > > +     uint32_t last_seqno[MSM_GPU_MAX_RINGS];
> > > > > +
> > > > > +     atomic_t preempt_state;
> > > > > +     spinlock_t eval_lock;
> > > > > +     struct timer_list preempt_timer;
> > > > > +
> > > > > +     unsigned int preempt_level;
> > > > > +     bool uses_gmem;
> > > > > +     bool skip_save_restore;
> > > > > +
> > > > > +     struct drm_gem_object *scratch_bo;
> > > > > +     void *scratch_ptr;
> > > > > +     uint64_t scratch_iova;
> > > > >
> > > > >       struct a6xx_gmu gmu;
> > > > >
> > > > > @@ -38,6 +81,10 @@ struct a6xx_gpu {
> > > > >       uint64_t shadow_iova;
> > > > >       uint32_t *shadow;
> > > > >
> > > > > +     struct drm_gem_object *pwrup_reglist_bo;
> > > > > +     void *pwrup_reglist_ptr;
> > > > > +     uint64_t pwrup_reglist_iova;
> > > > > +
> > > > >       bool has_whereami;
> > > > >
> > > > >       void __iomem *llc_mmio;
> > > > > @@ -49,6 +96,108 @@ struct a6xx_gpu {
> > > > >
> > > > >  #define to_a6xx_gpu(x) container_of(x, struct a6xx_gpu, base)
> > > > >
> > > > > +#define SCRATCH_USER_CTX_IOVA(ring_id, a6xx_gpu) \
> > > > > +     (a6xx_gpu->scratch_iova + (ring_id * sizeof(uint64_t)))
> > > > > +
> > > > > +/*
> > > > > + * In order to do lockless preemption we use a simple state machine to progress
> > > > > + * through the process.
> > > > > + *
> > > > > + * PREEMPT_NONE - no preemption in progress.  Next state START.
> > > > > + * PREEMPT_START - The trigger is evaluating if preemption is possible. Next
> > > > > + * states: TRIGGERED, NONE
> > > > > + * PREEMPT_FINISH - An intermediate state before moving back to NONE. Next
> > > > > + * state: NONE.
> > > > > + * PREEMPT_TRIGGERED: A preemption has been executed on the hardware. Next
> > > > > + * states: FAULTED, PENDING
> > > > > + * PREEMPT_FAULTED: A preemption timed out (never completed). This will trigger
> > > > > + * recovery.  Next state: N/A
> > > > > + * PREEMPT_PENDING: Preemption complete interrupt fired - the callback is
> > > > > + * checking the success of the operation. Next state: FAULTED, NONE.
> > > > > + */
> > > > > +
> > > > > +enum a6xx_preempt_state {
> > > > > +     PREEMPT_NONE = 0,
> > > > > +     PREEMPT_START,
> > > > > +     PREEMPT_FINISH,
> > > > > +     PREEMPT_TRIGGERED,
> > > > > +     PREEMPT_FAULTED,
> > > > > +     PREEMPT_PENDING,
> > > > > +};
> > > > > +
> > > > > +/*
> > > > > + * struct a6xx_preempt_record is a shared buffer between the microcode and the
> > > > > + * CPU to store the state for preemption. The record itself is much larger
> > > > > + * (2112k) but most of that is used by the CP for storage.
> > > > > + *
> > > > > + * There is a preemption record assigned per ringbuffer. When the CPU triggers a
> > > > > + * preemption, it fills out the record with the useful information (wptr, ring
> > > > > + * base, etc) and the microcode uses that information to set up the CP following
> > > > > + * the preemption.  When a ring is switched out, the CP will save the ringbuffer
> > > > > + * state back to the record. In this way, once the records are properly set up
> > > > > + * the CPU can quickly switch back and forth between ringbuffers by only
> > > > > + * updating a few registers (often only the wptr).
> > > > > + *
> > > > > + * These are the CPU aware registers in the record:
> > > > > + * @magic: Must always be 0xAE399D6EUL
> > > > > + * @info: Type of the record - written 0 by the CPU, updated by the CP
> > > > > + * @errno: preemption error record
> > > > > + * @data: Data field in YIELD and SET_MARKER packets, Written and used by CP
> > > > > + * @cntl: Value of RB_CNTL written by CPU, save/restored by CP
> > > > > + * @rptr: Value of RB_RPTR written by CPU, save/restored by CP
> > > > > + * @wptr: Value of RB_WPTR written by CPU, save/restored by CP
> > > > > + * @_pad: Reserved/padding
> > > > > + * @rptr_addr: Value of RB_RPTR_ADDR_LO|HI written by CPU, save/restored by CP
> > > > > + * @rbase: Value of RB_BASE written by CPU, save/restored by CP
> > > > > + * @counter: GPU address of the storage area for the preemption counters
> > > > > + */
> > > > > +struct a6xx_preempt_record {
> > > > > +     u32 magic;
> > > > > +     u32 info;
> > > > > +     u32 errno;
> > > > > +     u32 data;
> > > > > +     u32 cntl;
> > > > > +     u32 rptr;
> > > > > +     u32 wptr;
> > > > > +     u32 _pad;
> > > > > +     u64 rptr_addr;
> > > > > +     u64 rbase;
> > > > > +     u64 counter;
> > > > > +     u64 bv_rptr_addr;
> > > > > +};
> > > > > +
> > > > > +#define A6XX_PREEMPT_RECORD_MAGIC 0xAE399D6EUL
> > > > > +
> > > > > +#define PREEMPT_RECORD_SIZE_FALLBACK(size) \
> > > > > +     ((size) == 0 ? 4192 * SZ_1K : (size))
> > > > > +
> > > > > +#define PREEMPT_OFFSET_SMMU_INFO 0
> > > > > +#define PREEMPT_OFFSET_PRIV_NON_SECURE (PREEMPT_OFFSET_SMMU_INFO + 4096)
> > > > > +#define PREEMPT_OFFSET_PRIV_SECURE(size) \
> > > > > +     (PREEMPT_OFFSET_PRIV_NON_SECURE + PREEMPT_RECORD_SIZE_FALLBACK(size))
> > > > > +#define PREEMPT_SIZE(size) \
> > > > > +     (PREEMPT_OFFSET_PRIV_SECURE(size) + PREEMPT_RECORD_SIZE_FALLBACK(size))
> > > > > +
> > > > > +/*
> > > > > + * The preemption counter block is a storage area for the value of the
> > > > > + * preemption counters that are saved immediately before context switch. We
> > > > > + * append it on to the end of the allocation for the preemption record.
> > > > > + */
> > > > > +#define A6XX_PREEMPT_COUNTER_SIZE (16 * 4)
> > > > > +
> > > > > +#define A6XX_PREEMPT_USER_RECORD_SIZE (192 * 1024)
> > > > > +
> > > > > +struct a7xx_cp_smmu_info {
> > > > > +     u32 magic;
> > > > > +     u32 _pad4;
> > > > > +     u64 ttbr0;
> > > > > +     u32 asid;
> > > > > +     u32 context_idr;
> > > > > +     u32 context_bank;
> > > > > +};
> > > > > +
> > > > > +#define GEN7_CP_SMMU_INFO_MAGIC 0x241350d5UL
> > > > > +
> > > > >  /*
> > > > >   * Given a register and a count, return a value to program into
> > > > >   * REG_CP_PROTECT_REG(n) - this will block both reads and writes for
> > > > > @@ -106,6 +255,25 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
> > > > >  int a6xx_gmu_wrapper_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
> > > > >  void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu);
> > > > >
> > > > > +void a6xx_preempt_init(struct msm_gpu *gpu);
> > > > > +void a6xx_preempt_hw_init(struct msm_gpu *gpu);
> > > > > +void a6xx_preempt_trigger(struct msm_gpu *gpu);
> > > > > +void a6xx_preempt_irq(struct msm_gpu *gpu);
> > > > > +void a6xx_preempt_fini(struct msm_gpu *gpu);
> > > > > +int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
> > > > > +             struct msm_gpu_submitqueue *queue);
> > > > > +void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
> > > > > +             struct msm_gpu_submitqueue *queue);
> > > > > +
> > > > > +/* Return true if we are in a preempt state */
> > > > > +static inline bool a6xx_in_preempt(struct a6xx_gpu *a6xx_gpu)
> > > > > +{
> > > > > +     int preempt_state = atomic_read(&a6xx_gpu->preempt_state);
> > > > > +
> > > > > +     return !(preempt_state == PREEMPT_NONE ||
> > > > > +                     preempt_state == PREEMPT_FINISH);
> > > > > +}
> > > > > +
> > > > >  void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp,
> > > > >                      bool suspended);
> > > > >  unsigned long a6xx_gmu_get_freq(struct msm_gpu *gpu);
> > > > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_preempt.c b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
> > > > > new file mode 100644
> > > > > index 000000000000..0d402a3bcf5a
> > > > > --- /dev/null
> > > > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
> > > > > @@ -0,0 +1,434 @@
> > > > > +// SPDX-License-Identifier: GPL-2.0
> > > > > +/* Copyright (c) 2018, The Linux Foundation. All rights reserved. */
> > > > > +/* Copyright (c) 2023 Collabora, Ltd. */
> > > > > +/* Copyright (c) 2024 Valve Corporation */
> > > > > +
> > > > > +#include "msm_gem.h"
> > > > > +#include "a6xx_gpu.h"
> > > > > +#include "a6xx_gmu.xml.h"
> > > > > +#include "msm_mmu.h"
> > > > > +
> > > > > +#define FENCE_STATUS_WRITEDROPPED0_MASK 0x1
> > > > > +#define FENCE_STATUS_WRITEDROPPED1_MASK 0x2
> > > > > +
> > > > > +/*
> > > > > + * Try to transition the preemption state from old to new. Return
> > > > > + * true on success or false if the original state wasn't 'old'
> > > > > + */
> > > > > +static inline bool try_preempt_state(struct a6xx_gpu *a6xx_gpu,
> > > > > +             enum a6xx_preempt_state old, enum a6xx_preempt_state new)
> > > > > +{
> > > > > +     enum a6xx_preempt_state cur = atomic_cmpxchg(&a6xx_gpu->preempt_state,
> > > > > +             old, new);
> > > > > +
> > > > > +     return (cur == old);
> > > > > +}
> > > > > +
> > > > > +/*
> > > > > + * Force the preemption state to the specified state.  This is used in cases
> > > > > + * where the current state is known and won't change
> > > > > + */
> > > > > +static inline void set_preempt_state(struct a6xx_gpu *gpu,
> > > > > +             enum a6xx_preempt_state new)
> > > > > +{
> > > > > +     /*
> > > > > +      * preempt_state may be read by other cores trying to trigger a
> > > > > +      * preemption or in the interrupt handler so barriers are needed
> > > > > +      * before...
> > > > > +      */
> > > > > +     smp_mb__before_atomic();
> > > > > +     atomic_set(&gpu->preempt_state, new);
> > > > > +     /* ... and after*/
> > > > > +     smp_mb__after_atomic();
> > > > > +}
> > > > > +
> > > > > +/* Write the most recent wptr for the given ring into the hardware */
> > > > > +static inline void update_wptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > > > > +{
> > > > > +     unsigned long flags;
> > > > > +     uint32_t wptr, cur_wptr;
> > > > > +
> > > > > +     if (!ring)
> > > > > +             return;
> > > > > +
> > > > > +     spin_lock_irqsave(&ring->preempt_lock, flags);
> > > > > +
> > > > > +     if (ring->skip_inline_wptr) {
> > > > > +             wptr = get_wptr(ring);
> > > > > +
> > > > > +             gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > > > > +
> > > > > +             ring->skip_inline_wptr = false;
> > > > > +     }
> > > > > +
> > > > > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > > > +}
> > > > > +
> > > > > +/* Return the highest priority ringbuffer with something in it */
> > > > > +static struct msm_ringbuffer *get_next_ring(struct msm_gpu *gpu)
> > > > > +{
> > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > +
> > > > > +     unsigned long flags;
> > > > > +     int i;
> > > > > +
> > > > > +     for (i = 0; i < gpu->nr_rings; i++) {
> > > > > +             bool empty;
> > > > > +             struct msm_ringbuffer *ring = gpu->rb[i];
> > > > > +
> > > > > +             spin_lock_irqsave(&ring->preempt_lock, flags);
> > > > > +             empty = (get_wptr(ring) == gpu->funcs->get_rptr(gpu, ring));
> > > > > +             if (!empty && ring == a6xx_gpu->cur_ring)
> > > > > +                     empty = ring->memptrs->fence == a6xx_gpu->last_seqno[i];
> > > > > +             spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > > > +
> > > > > +             if (!empty)
> > > > > +                     return ring;
> > > > > +     }
> > > > > +
> > > > > +     return NULL;
> > > > > +}
> > > > > +
> > > > > +static void a6xx_preempt_timer(struct timer_list *t)
> > > > > +{
> > > > > +     struct a6xx_gpu *a6xx_gpu = from_timer(a6xx_gpu, t, preempt_timer);
> > > > > +     struct msm_gpu *gpu = &a6xx_gpu->base.base;
> > > > > +     struct drm_device *dev = gpu->dev;
> > > > > +
> > > > > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_FAULTED))
> > > > > +             return;
> > > > > +
> > > > > +     dev_err(dev->dev, "%s: preemption timed out\n", gpu->name);
> > > > > +     kthread_queue_work(gpu->worker, &gpu->recover_work);
> > > > > +}
> > > > > +
> > > > > +void a6xx_preempt_irq(struct msm_gpu *gpu)
> > > > > +{
> > > > > +     uint32_t status;
> > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > +     struct drm_device *dev = gpu->dev;
> > > > > +
> > > > > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_PENDING))
> > > > > +             return;
> > > > > +
> > > > > +     /* Delete the preemption watchdog timer */
> > > > > +     del_timer(&a6xx_gpu->preempt_timer);
> > > > > +
> > > > > +     /*
> > > > > +      * The hardware should be setting the stop bit of CP_CONTEXT_SWITCH_CNTL
> > > > > +      * to zero before firing the interrupt, but there is a non zero chance
> > > > > +      * of a hardware condition or a software race that could set it again
> > > > > +      * before we have a chance to finish. If that happens, log and go for
> > > > > +      * recovery
> > > > > +      */
> > > > > +     status = gpu_read(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL);
> > > > > +     if (unlikely(status & 0x1)) {
> > > > > +             DRM_DEV_ERROR(&gpu->pdev->dev,
> > > > > +                                       "!!!!!!!!!!!!!!!! preemption faulted !!!!!!!!!!!!!! irq\n");
> > > > > +             set_preempt_state(a6xx_gpu, PREEMPT_FAULTED);
> > > > > +             dev_err(dev->dev, "%s: Preemption failed to complete\n",
> > > > > +                     gpu->name);
> > > > > +             kthread_queue_work(gpu->worker, &gpu->recover_work);
> > > > > +             return;
> > > > > +     }
> > > > > +
> > > > > +     a6xx_gpu->cur_ring = a6xx_gpu->next_ring;
> > > > > +     a6xx_gpu->next_ring = NULL;
> > > > > +
> > > > > +     /* Make sure the write to cur_ring is posted before the change in state */
> > > > > +     wmb();
> > > > > +
> > > > > +     set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
> > > > > +
> > > > > +     update_wptr(gpu, a6xx_gpu->cur_ring);
> > > > > +
> > > > > +     set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > > > > +
> > > > > +     /*
> > > > > +      * Retrigger preemption to avoid a deadlock that might occur when preemption
> > > > > +      * is skipped due to it being already in flight when requested.
> > > > > +      */
> > > > > +     a6xx_preempt_trigger(gpu);
> > > > > +}
> > > > > +
> > > > > +void a6xx_preempt_hw_init(struct msm_gpu *gpu)
> > > > > +{
> > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > +     int i;
> > > > > +
> > > > > +     /* No preemption if we only have one ring */
> > > > > +     if (gpu->nr_rings == 1)
> > > > > +             return;
> > > > > +
> > > > > +     for (i = 0; i < gpu->nr_rings; i++) {
> > > > > +             struct a6xx_preempt_record *record_ptr =
> > > > > +                     a6xx_gpu->preempt[i] + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > > > > +             record_ptr->wptr = 0;
> > > > > +             record_ptr->rptr = 0;
> > > > > +             record_ptr->rptr_addr = shadowptr(a6xx_gpu, gpu->rb[i]);
> > > > > +             record_ptr->info = 0;
> > > > > +             record_ptr->data = 0;
> > > > > +             record_ptr->rbase = gpu->rb[i]->iova;
> > > > > +     }
> > > > > +
> > > > > +     /* Write a 0 to signal that we aren't switching pagetables */
> > > > > +     gpu_write64(gpu, REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO, 0);
> > > > > +
> > > > > +     /* Enable the GMEM save/restore feature for preemption */
> > > > > +     gpu_write(gpu, REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE, 0x1);
> > > > > +
> > > > > +     /* Reset the preemption state */
> > > > > +     set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > > > > +
> > > > > +     spin_lock_init(&a6xx_gpu->eval_lock);
> > > > > +
> > > > > +     /* Always come up on rb 0 */
> > > > > +     a6xx_gpu->cur_ring = gpu->rb[0];
> > > > > +}
> > > > > +
> > > > > +void a6xx_preempt_trigger(struct msm_gpu *gpu)
> > > > > +{
> > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > +     u64 preempt_offset_priv_secure;
> > > > > +     unsigned long flags;
> > > > > +     struct msm_ringbuffer *ring;
> > > > > +     uint64_t user_ctx_iova;
> > > > > +     unsigned int cntl;
> > > > > +
> > > > > +     if (gpu->nr_rings == 1)
> > > > > +             return;
> > > > > +
> > > > > +     /*
> > > > > +      * Lock to make sure another thread attempting preemption doesn't skip it
> > > > > +      * while we are still evaluating the next ring. This makes sure the other
> > > > > +      * thread does start preemption if we abort it and avoids a soft lock.
> > > > > +      */
> > > > > +     spin_lock_irqsave(&a6xx_gpu->eval_lock, flags);
> > > > > +
> > > > > +     /*
> > > > > +      * Try to start preemption by moving from NONE to START. If
> > > > > +      * unsuccessful, a preemption is already in flight
> > > > > +      */
> > > > > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_NONE, PREEMPT_START)) {
> > > > > +             spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > > > > +             return;
> > > > > +     }
> > > > > +
> > > > > +     cntl = (((a6xx_gpu->preempt_level << 6) & 0xC0) |
> > > > > +             ((a6xx_gpu->skip_save_restore << 9) & 0x200) |
> > > > > +             ((a6xx_gpu->uses_gmem << 8) & 0x100) | 0x1);
> > > > > +
> > > > > +     /* Get the next ring to preempt to */
> > > > > +     ring = get_next_ring(gpu);
> > > > > +
> > > > > +     /*
> > > > > +      * If no ring is populated or the highest priority ring is the current
> > > > > +      * one do nothing except to update the wptr to the latest and greatest
> > > > > +      */
> > > > > +     if (!ring || (a6xx_gpu->cur_ring == ring)) {
> > > > > +             set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
> > > > > +             update_wptr(gpu, a6xx_gpu->cur_ring);
> > > > > +             set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > > > > +             spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > > > > +             return;
> > > > > +     }
> > > > > +
> > > > > +     spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > > > > +
> > > > > +     spin_lock_irqsave(&ring->preempt_lock, flags);
> > > > > +
> > > > > +     struct a7xx_cp_smmu_info *smmu_info_ptr =
> > > > > +             a6xx_gpu->preempt[ring->id] + PREEMPT_OFFSET_SMMU_INFO;
> > > > > +     struct a6xx_preempt_record *record_ptr =
> > > > > +             a6xx_gpu->preempt[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > > > > +     u64 ttbr0 = ring->memptrs->ttbr0;
> > > > > +     u32 context_idr = ring->memptrs->context_idr;
> > > > > +
> > > > > +     smmu_info_ptr->ttbr0 = ttbr0;
> > > > > +     smmu_info_ptr->context_idr = context_idr;
> > > > > +     record_ptr->wptr = get_wptr(ring);
> > > > > +
> > > > > +     /*
> > > > > +      * The GPU will write the wptr we set above when we preempt. Reset
> > > > > +      * skip_inline_wptr to make sure that we don't write WPTR to the same
> > > > > +      * thing twice. It's still possible subsequent submissions will update
> > > > > +      * wptr again, in which case they will set the flag to true. This has
> > > > > +      * to be protected by the lock for setting the flag and updating wptr
> > > > > +      * to be atomic.
> > > > > +      */
> > > > > +     ring->skip_inline_wptr = false;
> > > > > +
> > > > > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > > > +
> > > > > +     gpu_write64(gpu,
> > > > > +             REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO,
> > > > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_SMMU_INFO);
> > > > > +
> > > > > +     gpu_write64(gpu,
> > > > > +             REG_A6XX_CP_CONTEXT_SWITCH_PRIV_NON_SECURE_RESTORE_ADDR,
> > > > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE);
> > > > > +
> > > > > +     preempt_offset_priv_secure =
> > > > > +             PREEMPT_OFFSET_PRIV_SECURE(adreno_gpu->info->preempt_record_size);
> > > > > +     gpu_write64(gpu,
> > > > > +             REG_A6XX_CP_CONTEXT_SWITCH_PRIV_SECURE_RESTORE_ADDR,
> > > > > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure);
> > > > > +
> > > > > +     /*
> > > > > +      * Use the user context iova from the scratch memory that the CP may
> > > > > +      * have written as part of the ring switch out.
> > > > > +      */
> > > > > +     user_ctx_iova = *((uint64_t *)a6xx_gpu->scratch_ptr + ring->id);
> > > > > +
> > > > > +     gpu_write64(gpu,
> > > > > +             REG_A6XX_CP_CONTEXT_SWITCH_NON_PRIV_RESTORE_ADDR,
> > > > > +             user_ctx_iova);
> > > > > +
> > > > > +     a6xx_gpu->next_ring = ring;
> > > > > +
> > > > > +     /* Start a timer to catch a stuck preemption */
> > > > > +     mod_timer(&a6xx_gpu->preempt_timer, jiffies + msecs_to_jiffies(10000));
> > > > > +
> > > > > +     /* Set the preemption state to triggered */
> > > > > +     set_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED);
> > > > > +
> > > > > +     /* Make sure any previous writes to WPTR are posted */
> > > > > +     gpu_read(gpu, REG_A6XX_CP_RB_WPTR);
> > > > > +
> > > > > +     /* Make sure everything is written before hitting the button */
> > > > > +     wmb();
> > > > > +
> > > > > +     /* Trigger the preemption */
> > > > > +     gpu_write(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL, cntl);
> > > > > +}
> > > > > +
> > > > > +static int preempt_init_ring(struct a6xx_gpu *a6xx_gpu,
> > > > > +             struct msm_ringbuffer *ring)
> > > > > +{
> > > > > +     struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
> > > > > +     struct msm_gpu *gpu = &adreno_gpu->base;
> > > > > +     struct drm_gem_object *bo = NULL;
> > > > > +     phys_addr_t ttbr;
> > > > > +     u64 iova = 0;
> > > > > +     void *ptr;
> > > > > +     int asid;
> > > > > +
> > > > > +     ptr = msm_gem_kernel_new(gpu->dev,
> > > > > +             PREEMPT_SIZE(adreno_gpu->info->preempt_record_size),
> > > > > +             MSM_BO_WC | MSM_BO_MAP_PRIV, gpu->aspace, &bo, &iova);
> > > > > +
> > > > > +     memset(ptr, 0, PREEMPT_SIZE(adreno_gpu->info->preempt_record_size));
> > > > > +
> > > > > +     if (IS_ERR(ptr))
> > > > > +             return PTR_ERR(ptr);
> > > > > +
> > > > > +     a6xx_gpu->preempt_bo[ring->id] = bo;
> > > > > +     a6xx_gpu->preempt_iova[ring->id] = iova;
> > > > > +     a6xx_gpu->preempt[ring->id] = ptr;
> > > > > +
> > > > > +     struct a7xx_cp_smmu_info *smmu_info_ptr = ptr + PREEMPT_OFFSET_SMMU_INFO;
> > > > > +     struct a6xx_preempt_record *record_ptr = ptr + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > > > > +
> > > > > +     msm_iommu_pagetable_params(gpu->aspace->mmu, &ttbr, &asid);
> > > > > +
> > > > > +     smmu_info_ptr->magic = GEN7_CP_SMMU_INFO_MAGIC;
> > > > > +     smmu_info_ptr->ttbr0 = ttbr;
> > > > > +     smmu_info_ptr->asid = 0xdecafbad;
> > > > > +     smmu_info_ptr->context_idr = 0;
> > > > > +
> > > > > +     /* Set up the defaults on the preemption record */
> > > > > +     record_ptr->magic = A6XX_PREEMPT_RECORD_MAGIC;
> > > > > +     record_ptr->info = 0;
> > > > > +     record_ptr->data = 0;
> > > > > +     record_ptr->rptr = 0;
> > > > > +     record_ptr->wptr = 0;
> > > > > +     record_ptr->cntl = MSM_GPU_RB_CNTL_DEFAULT;
> > > > > +     record_ptr->rbase = ring->iova;
> > > > > +     record_ptr->counter = 0;
> > > > > +     record_ptr->bv_rptr_addr = rbmemptr(ring, bv_rptr);
> > > > > +
> > > > > +     return 0;
> > > > > +}
> > > > > +
> > > > > +void a6xx_preempt_fini(struct msm_gpu *gpu)
> > > > > +{
> > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > +     int i;
> > > > > +
> > > > > +     for (i = 0; i < gpu->nr_rings; i++)
> > > > > +             msm_gem_kernel_put(a6xx_gpu->preempt_bo[i], gpu->aspace);
> > > > > +}
> > > > > +
> > > > > +void a6xx_preempt_init(struct msm_gpu *gpu)
> > > > > +{
> > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > +     int i;
> > > > > +
> > > > > +     /* No preemption if we only have one ring */
> > > > > +     if (gpu->nr_rings <= 1)
> > > > > +             return;
> > > > > +
> > > > > +     for (i = 0; i < gpu->nr_rings; i++) {
> > > > > +             if (preempt_init_ring(a6xx_gpu, gpu->rb[i]))
> > > > > +                     goto fail;
> > > > > +     }
> > > > > +
> > > > > +     /* TODO: make this configurable? */
> > > > > +     a6xx_gpu->preempt_level = 1;
> > > > > +     a6xx_gpu->uses_gmem = 1;
> > > > > +     a6xx_gpu->skip_save_restore = 1;
> > > > > +
> > > > > +     a6xx_gpu->scratch_ptr  = msm_gem_kernel_new(gpu->dev,
> > > > > +                     gpu->nr_rings * sizeof(uint64_t), MSM_BO_WC,
> > > > > +                     gpu->aspace, &a6xx_gpu->scratch_bo,
> > > > > +                     &a6xx_gpu->scratch_iova);
> > > > > +
> > > > > +     if (IS_ERR(a6xx_gpu->scratch_ptr))
> > > > > +             goto fail;
> > > > > +
> > > > > +     timer_setup(&a6xx_gpu->preempt_timer, a6xx_preempt_timer, 0);
> > > > > +
> > > > > +     return;
> > > > > +fail:
> > > > > +     /*
> > > > > +      * On any failure our adventure is over. Clean up and
> > > > > +      * set nr_rings to 1 to force preemption off
> > > > > +      */
> > > > > +     a6xx_preempt_fini(gpu);
> > > > > +     gpu->nr_rings = 1;
> > > > > +
> > > > > +     return;
> > > > > +}
> > > > > +
> > > > > +void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
> > > > > +             struct msm_gpu_submitqueue *queue)
> > > > > +{
> > > > > +     if (!queue->bo)
> > > > > +             return;
> > > > > +
> > > > > +     msm_gem_kernel_put(queue->bo, gpu->aspace);
> > > > > +}
> > > > > +
> > > > > +int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
> > > > > +             struct msm_gpu_submitqueue *queue)
> > > > > +{
> > > > > +     void *ptr;
> > > > > +
> > > > > +     /*
> > > > > +      * Create a per submitqueue buffer for the CP to save and restore user
> > > > > +      * specific information such as the VPC streamout data.
> > > > > +      */
> > > > > +     ptr = msm_gem_kernel_new(gpu->dev, A6XX_PREEMPT_USER_RECORD_SIZE,
> > > > > +                     MSM_BO_WC, gpu->aspace, &queue->bo, &queue->bo_iova);
> > > > > +
> > > > > +     if (IS_ERR(ptr))
> > > > > +             return PTR_ERR(ptr);
> > > > > +
> > > > > +     return 0;
> > > > > +}
> > > > > diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.h b/drivers/gpu/drm/msm/msm_ringbuffer.h
> > > > > index 40791b2ade46..7dde6a312511 100644
> > > > > --- a/drivers/gpu/drm/msm/msm_ringbuffer.h
> > > > > +++ b/drivers/gpu/drm/msm/msm_ringbuffer.h
> > > > > @@ -36,6 +36,7 @@ struct msm_rbmemptrs {
> > > > >
> > > > >       volatile struct msm_gpu_submit_stats stats[MSM_GPU_SUBMIT_STATS_COUNT];
> > > > >       volatile u64 ttbr0;
> > > > > +     volatile u32 context_idr;
> > > > >  };
> > > > >
> > > > >  struct msm_cp_state {
> > > > > @@ -100,6 +101,12 @@ struct msm_ringbuffer {
> > > > >        * preemption.  Can be aquired from irq context.
> > > > >        */
> > > > >       spinlock_t preempt_lock;
> > > > > +
> > > > > +     /*
> > > > > +      * Whether we skipped writing wptr and it needs to be updated in the
> > > > > +      * future when the ring becomes current.
> > > > > +      */
> > > > > +     bool skip_inline_wptr;
> > > > >  };
> > > > >
> > > > >  struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int id,
> > > > >
> > > > > --
> > > > > 2.46.0
> > > > >
> > > > >

Akhil P Oommen Aug. 27, 2024, 7:48 p.m. UTC | #11

On Fri, Aug 23, 2024 at 10:23:48AM +0100, Connor Abbott wrote:
> On Fri, Aug 23, 2024 at 10:21 AM Connor Abbott <[e-mail]> wrote:
> >
> > On Thu, Aug 22, 2024 at 9:06 PM Akhil P Oommen <[e-mail]> wrote:
> > >
> > > On Wed, Aug 21, 2024 at 05:02:56PM +0100, Connor Abbott wrote:
> > > > On Mon, Aug 19, 2024 at 9:09 PM Akhil P Oommen <[e-mail]> wrote:
> > > > >
> > > > > On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
> > > > > > This patch implements preemption feature for A6xx targets, this allows
> > > > > > the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
> > > > > > hardware as such supports multiple levels of preemption granularities,
> > > > > > ranging from coarse grained(ringbuffer level) to a more fine grained
> > > > > > such as draw-call level or a bin boundary level preemption. This patch
> > > > > > enables the basic preemption level, with more fine grained preemption
> > > > > > support to follow.
> > > > > >
> > > > > > Signed-off-by: Sharat Masetty <[e-mail]>
> > > > > > Signed-off-by: Antonino Maniscalco <[e-mail]>
> > > > > > ---
> > > > >
> > > > > No postamble packets which resets perfcounters? It is necessary. Also, I
> > > > > think we should disable preemption during profiling like we disable slumber.
> > > > >
> > > > > -Akhil.
> > > >
> > > > I don't see anything in kgsl which disables preemption during
> > > > profiling. It disables resetting perfcounters when doing system-wide
> > > > profiling, like freedreno, and in that case I assume preempting is
> > > > fine because the system profiler has a complete view of everything and
> > > > should "see" preemptions through the traces. For something like
> > > > VK_KHR_performance_query I suppose we'd want to disable preemption
> > > > because we disable saving/restoring perf counters, but that has to
> > > > happen in userspace because the kernel doesn't know what userspace
> > > > does.
> > > >
> > >
> > > KGSL does some sort of arbitration of perfcounter configurations and
> > > adds the select/enablement reg configuration as part of dynamic
> > > power up register list which we are not doing here. Is this something
> > > you are taking care of from userspace via preamble?
> > >
> > > -Akhil
> >
> > I don't think we have to take care of that in userspace, because Mesa
> > will always configure the counter registers before reading them in the
> > same submission, and if it gets preempted in the meantime then we're
> > toast anyways (due to not saving/restoring perf counters). kgsl sets
> > them from userspace, which is why it has to do something to set them
> 
> Sorry, should be "kgsl sets them from the kernel".
> 
> > after IFPC slumber or a context switch when the HW state is gone.
> > Also, because the upstream approach doesn't play nicely with system
> > profilers like perfetto, VK_KHR_performance_query is hidden by default
> > behind a debug flag in turnip. So there's already an element of "this
> > is unsupported, you have to know what you're doing to use it."

But when you have composition on GPU enabled, there will be very frequent
preemption. And I don't know how usable profiling tools will be in that
case unless you disable preemption with a Mesa debug flag. But for that
to work, all existing submitqueues should be destroyed and recreated.

So I was thinking that we can use the sysprof propertry to force L0
preemption from kernel. 

-Akhil.

> >
> > Connor
> >
> > >
> > > > Connor
> > > >
> > > > >
> > > > > >  drivers/gpu/drm/msm/Makefile              |   1 +
> > > > > >  drivers/gpu/drm/msm/adreno/a6xx_gpu.c     | 323 +++++++++++++++++++++-
> > > > > >  drivers/gpu/drm/msm/adreno/a6xx_gpu.h     | 168 ++++++++++++
> > > > > >  drivers/gpu/drm/msm/adreno/a6xx_preempt.c | 434 ++++++++++++++++++++++++++++++
> > > > > >  drivers/gpu/drm/msm/msm_ringbuffer.h      |   7 +
> > > > > >  5 files changed, 924 insertions(+), 9 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile
> > > > > > index f5e2838c6a76..32e915109a59 100644
> > > > > > --- a/drivers/gpu/drm/msm/Makefile
> > > > > > +++ b/drivers/gpu/drm/msm/Makefile
> > > > > > @@ -23,6 +23,7 @@ adreno-y := \
> > > > > >       adreno/a6xx_gpu.o \
> > > > > >       adreno/a6xx_gmu.o \
> > > > > >       adreno/a6xx_hfi.o \
> > > > > > +     adreno/a6xx_preempt.o \
> > > > > >
> > > > > >  adreno-$(CONFIG_DEBUG_FS) += adreno/a5xx_debugfs.o \
> > > > > >
> > > > > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > > > > index 32a4faa93d7f..1a90db5759b8 100644
> > > > > > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > > > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > > > > > @@ -16,6 +16,83 @@
> > > > > >
> > > > > >  #define GPU_PAS_ID 13
> > > > > >
> > > > > > +/* IFPC & Preemption static powerup restore list */
> > > > > > +static const uint32_t a7xx_pwrup_reglist[] = {
> > > > > > +     REG_A6XX_UCHE_TRAP_BASE,
> > > > > > +     REG_A6XX_UCHE_TRAP_BASE + 1,
> > > > > > +     REG_A6XX_UCHE_WRITE_THRU_BASE,
> > > > > > +     REG_A6XX_UCHE_WRITE_THRU_BASE + 1,
> > > > > > +     REG_A6XX_UCHE_GMEM_RANGE_MIN,
> > > > > > +     REG_A6XX_UCHE_GMEM_RANGE_MIN + 1,
> > > > > > +     REG_A6XX_UCHE_GMEM_RANGE_MAX,
> > > > > > +     REG_A6XX_UCHE_GMEM_RANGE_MAX + 1,
> > > > > > +     REG_A6XX_UCHE_CACHE_WAYS,
> > > > > > +     REG_A6XX_UCHE_MODE_CNTL,
> > > > > > +     REG_A6XX_RB_NC_MODE_CNTL,
> > > > > > +     REG_A6XX_RB_CMP_DBG_ECO_CNTL,
> > > > > > +     REG_A7XX_GRAS_NC_MODE_CNTL,
> > > > > > +     REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE,
> > > > > > +     REG_A6XX_UCHE_GBIF_GX_CONFIG,
> > > > > > +     REG_A6XX_UCHE_CLIENT_PF,
> > > > > > +};
> > > > > > +
> > > > > > +static const uint32_t a7xx_ifpc_pwrup_reglist[] = {
> > > > > > +     REG_A6XX_TPL1_NC_MODE_CNTL,
> > > > > > +     REG_A6XX_SP_NC_MODE_CNTL,
> > > > > > +     REG_A6XX_CP_DBG_ECO_CNTL,
> > > > > > +     REG_A6XX_CP_PROTECT_CNTL,
> > > > > > +     REG_A6XX_CP_PROTECT(0),
> > > > > > +     REG_A6XX_CP_PROTECT(1),
> > > > > > +     REG_A6XX_CP_PROTECT(2),
> > > > > > +     REG_A6XX_CP_PROTECT(3),
> > > > > > +     REG_A6XX_CP_PROTECT(4),
> > > > > > +     REG_A6XX_CP_PROTECT(5),
> > > > > > +     REG_A6XX_CP_PROTECT(6),
> > > > > > +     REG_A6XX_CP_PROTECT(7),
> > > > > > +     REG_A6XX_CP_PROTECT(8),
> > > > > > +     REG_A6XX_CP_PROTECT(9),
> > > > > > +     REG_A6XX_CP_PROTECT(10),
> > > > > > +     REG_A6XX_CP_PROTECT(11),
> > > > > > +     REG_A6XX_CP_PROTECT(12),
> > > > > > +     REG_A6XX_CP_PROTECT(13),
> > > > > > +     REG_A6XX_CP_PROTECT(14),
> > > > > > +     REG_A6XX_CP_PROTECT(15),
> > > > > > +     REG_A6XX_CP_PROTECT(16),
> > > > > > +     REG_A6XX_CP_PROTECT(17),
> > > > > > +     REG_A6XX_CP_PROTECT(18),
> > > > > > +     REG_A6XX_CP_PROTECT(19),
> > > > > > +     REG_A6XX_CP_PROTECT(20),
> > > > > > +     REG_A6XX_CP_PROTECT(21),
> > > > > > +     REG_A6XX_CP_PROTECT(22),
> > > > > > +     REG_A6XX_CP_PROTECT(23),
> > > > > > +     REG_A6XX_CP_PROTECT(24),
> > > > > > +     REG_A6XX_CP_PROTECT(25),
> > > > > > +     REG_A6XX_CP_PROTECT(26),
> > > > > > +     REG_A6XX_CP_PROTECT(27),
> > > > > > +     REG_A6XX_CP_PROTECT(28),
> > > > > > +     REG_A6XX_CP_PROTECT(29),
> > > > > > +     REG_A6XX_CP_PROTECT(30),
> > > > > > +     REG_A6XX_CP_PROTECT(31),
> > > > > > +     REG_A6XX_CP_PROTECT(32),
> > > > > > +     REG_A6XX_CP_PROTECT(33),
> > > > > > +     REG_A6XX_CP_PROTECT(34),
> > > > > > +     REG_A6XX_CP_PROTECT(35),
> > > > > > +     REG_A6XX_CP_PROTECT(36),
> > > > > > +     REG_A6XX_CP_PROTECT(37),
> > > > > > +     REG_A6XX_CP_PROTECT(38),
> > > > > > +     REG_A6XX_CP_PROTECT(39),
> > > > > > +     REG_A6XX_CP_PROTECT(40),
> > > > > > +     REG_A6XX_CP_PROTECT(41),
> > > > > > +     REG_A6XX_CP_PROTECT(42),
> > > > > > +     REG_A6XX_CP_PROTECT(43),
> > > > > > +     REG_A6XX_CP_PROTECT(44),
> > > > > > +     REG_A6XX_CP_PROTECT(45),
> > > > > > +     REG_A6XX_CP_PROTECT(46),
> > > > > > +     REG_A6XX_CP_PROTECT(47),
> > > > > > +     REG_A6XX_CP_AHB_CNTL,
> > > > > > +};
> > > > > > +
> > > > > > +
> > > > > >  static inline bool _a6xx_check_idle(struct msm_gpu *gpu)
> > > > > >  {
> > > > > >       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > > @@ -68,6 +145,8 @@ static void update_shadow_rptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > > > > >
> > > > > >  static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > > > > >  {
> > > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > >       uint32_t wptr;
> > > > > >       unsigned long flags;
> > > > > >
> > > > > > @@ -81,12 +160,26 @@ static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > > > > >       /* Make sure to wrap wptr if we need to */
> > > > > >       wptr = get_wptr(ring);
> > > > > >
> > > > > > -     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > > > > -
> > > > > >       /* Make sure everything is posted before making a decision */
> > > > > >       mb();
> > > > > >
> > > > > > -     gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > > > > > +     /* Update HW if this is the current ring and we are not in preempt*/
> > > > > > +     if (!a6xx_in_preempt(a6xx_gpu)) {
> > > > > > +             /*
> > > > > > +              * Order the reads of the preempt state and cur_ring. This
> > > > > > +              * matches the barrier after writing cur_ring.
> > > > > > +              */
> > > > > > +             rmb();
> > > > > > +
> > > > > > +             if (a6xx_gpu->cur_ring == ring)
> > > > > > +                     gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > > > > > +             else
> > > > > > +                     ring->skip_inline_wptr = true;
> > > > > > +     } else {
> > > > > > +             ring->skip_inline_wptr = true;
> > > > > > +     }
> > > > > > +
> > > > > > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > > > >  }
> > > > > >
> > > > > >  static void get_stats_counter(struct msm_ringbuffer *ring, u32 counter,
> > > > > > @@ -138,12 +231,14 @@ static void a6xx_set_pagetable(struct a6xx_gpu *a6xx_gpu,
> > > > > >
> > > > > >       /*
> > > > > >        * Write the new TTBR0 to the memstore. This is good for debugging.
> > > > > > +      * Needed for preemption
> > > > > >        */
> > > > > > -     OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > > > > > +     OUT_PKT7(ring, CP_MEM_WRITE, 5);
> > > > > >       OUT_RING(ring, CP_MEM_WRITE_0_ADDR_LO(lower_32_bits(memptr)));
> > > > > >       OUT_RING(ring, CP_MEM_WRITE_1_ADDR_HI(upper_32_bits(memptr)));
> > > > > >       OUT_RING(ring, lower_32_bits(ttbr));
> > > > > > -     OUT_RING(ring, (asid << 16) | upper_32_bits(ttbr));
> > > > > > +     OUT_RING(ring, upper_32_bits(ttbr));
> > > > > > +     OUT_RING(ring, ctx->seqno);
> > > > > >
> > > > > >       /*
> > > > > >        * Sync both threads after switching pagetables and enable BR only
> > > > > > @@ -268,12 +363,55 @@ static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > > > >       a6xx_flush(gpu, ring);
> > > > > >  }
> > > > > >
> > > > > > +static void a6xx_emit_set_pseudo_reg(struct msm_ringbuffer *ring,
> > > > > > +             struct a6xx_gpu *a6xx_gpu, struct msm_gpu_submitqueue *queue)
> > > > > > +{
> > > > > > +     u64 preempt_offset_priv_secure;
> > > > > > +
> > > > > > +     OUT_PKT7(ring, CP_SET_PSEUDO_REG, 15);
> > > > > > +
> > > > > > +     OUT_RING(ring, SMMU_INFO);
> > > > > > +     /* don't save SMMU, we write the record from the kernel instead */
> > > > > > +     OUT_RING(ring, 0);
> > > > > > +     OUT_RING(ring, 0);
> > > > > > +
> > > > > > +     /* privileged and non secure buffer save */
> > > > > > +     OUT_RING(ring, NON_SECURE_SAVE_ADDR);
> > > > > > +     OUT_RING(ring, lower_32_bits(
> > > > > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE));
> > > > > > +     OUT_RING(ring, upper_32_bits(
> > > > > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE));
> > > > > > +     OUT_RING(ring, SECURE_SAVE_ADDR);
> > > > > > +     preempt_offset_priv_secure =
> > > > > > +             PREEMPT_OFFSET_PRIV_SECURE(a6xx_gpu->base.info->preempt_record_size);
> > > > > > +     OUT_RING(ring, lower_32_bits(
> > > > > > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure));
> > > > > > +     OUT_RING(ring, upper_32_bits(
> > > > > > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure));
> > > > > > +
> > > > > > +     /* user context buffer save */
> > > > > > +     OUT_RING(ring, NON_PRIV_SAVE_ADDR);
> > > > > > +     if (queue) {
> > > > > > +             OUT_RING(ring, lower_32_bits(queue->bo_iova));
> > > > > > +             OUT_RING(ring, upper_32_bits(queue->bo_iova));
> > > > > > +     } else {
> > > > > > +             OUT_RING(ring, 0);
> > > > > > +             OUT_RING(ring, 0);
> > > > > > +     }
> > > > > > +
> > > > > > +     OUT_RING(ring, COUNTER);
> > > > > > +     /* seems OK to set to 0 to disable it */
> > > > > > +     OUT_RING(ring, 0);
> > > > > > +     OUT_RING(ring, 0);
> > > > > > +}
> > > > > > +
> > > > > >  static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > > > >  {
> > > > > >       unsigned int index = submit->seqno % MSM_GPU_SUBMIT_STATS_COUNT;
> > > > > >       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > >       struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > >       struct msm_ringbuffer *ring = submit->ring;
> > > > > > +     uint64_t scratch_dest = SCRATCH_USER_CTX_IOVA(ring->id, a6xx_gpu);
> > > > > >       unsigned int i, ibs = 0;
> > > > > >
> > > > > >       /*
> > > > > > @@ -283,6 +421,25 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > > > >       OUT_PKT7(ring, CP_THREAD_CONTROL, 1);
> > > > > >       OUT_RING(ring, CP_THREAD_CONTROL_0_SYNC_THREADS | CP_SET_THREAD_BR);
> > > > > >
> > > > > > +     /*
> > > > > > +      * If preemption is enabled, then set the pseudo register for the save
> > > > > > +      * sequence
> > > > > > +      */
> > > > > > +     if (gpu->nr_rings > 1) {
> > > > > > +             a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, submit->queue);
> > > > > > +
> > > > > > +             /*
> > > > > > +              * Ask CP to save the user context buffer's iova address to a
> > > > > > +              * scratch memory region, this is needed if the CP preempts
> > > > > > +              * this ring in between this submit's IB list.
> > > > > > +              */
> > > > > > +             OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > > > > > +             OUT_RING(ring, lower_32_bits(scratch_dest));
> > > > > > +             OUT_RING(ring, upper_32_bits(scratch_dest));
> > > > > > +             OUT_RING(ring, lower_32_bits(submit->queue->bo_iova));
> > > > > > +             OUT_RING(ring, upper_32_bits(submit->queue->bo_iova));
> > > > > > +     }
> > > > > > +
> > > > > >       a6xx_set_pagetable(a6xx_gpu, ring, submit->queue->ctx);
> > > > > >
> > > > > >       get_stats_counter(ring, REG_A7XX_RBBM_PERFCTR_CP(0),
> > > > > > @@ -376,6 +533,8 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > > > >       OUT_RING(ring, upper_32_bits(rbmemptr(ring, bv_fence)));
> > > > > >       OUT_RING(ring, submit->seqno);
> > > > > >
> > > > > > +     a6xx_gpu->last_seqno[ring->id] = submit->seqno;
> > > > > > +
> > > > > >       /* write the ringbuffer timestamp */
> > > > > >       OUT_PKT7(ring, CP_EVENT_WRITE, 4);
> > > > > >       OUT_RING(ring, CACHE_CLEAN | CP_EVENT_WRITE_0_IRQ | BIT(27));
> > > > > > @@ -389,10 +548,42 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
> > > > > >       OUT_PKT7(ring, CP_SET_MARKER, 1);
> > > > > >       OUT_RING(ring, 0x100); /* IFPC enable */
> > > > > >
> > > > > > +     /* If preemption is enabled */
> > > > > > +     if (gpu->nr_rings > 1) {
> > > > > > +             /*
> > > > > > +              * Reset the scratch region as we are done with the
> > > > > > +              * IB list of this submission
> > > > > > +              */
> > > > > > +             OUT_PKT7(ring, CP_MEM_WRITE, 4);
> > > > > > +             OUT_RING(ring, lower_32_bits(scratch_dest));
> > > > > > +             OUT_RING(ring, upper_32_bits(scratch_dest));
> > > > > > +             OUT_RING(ring, 0x00);
> > > > > > +             OUT_RING(ring, 0x00);
> > > > > > +
> > > > > > +             /* Yield the floor on command completion */
> > > > > > +             OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
> > > > > > +
> > > > > > +             /*
> > > > > > +              * If dword[2:1] are non zero, they specify an address for
> > > > > > +              * the CP to write the value of dword[3] to on preemption
> > > > > > +              * complete. Write 0 to skip the write
> > > > > > +              */
> > > > > > +             OUT_RING(ring, 0x00);
> > > > > > +             OUT_RING(ring, 0x00);
> > > > > > +             /* Data value - not used if the address above is 0 */
> > > > > > +             OUT_RING(ring, 0x01);
> > > > > > +             /* generate interrupt on preemption completion */
> > > > > > +             OUT_RING(ring, 0x00);
> > > > > > +     }
> > > > > > +
> > > > > > +
> > > > > >       trace_msm_gpu_submit_flush(submit,
> > > > > >               gpu_read64(gpu, REG_A6XX_CP_ALWAYS_ON_COUNTER));
> > > > > >
> > > > > >       a6xx_flush(gpu, ring);
> > > > > > +
> > > > > > +     /* Check to see if we need to start preemption */
> > > > > > +     a6xx_preempt_trigger(gpu);
> > > > > >  }
> > > > > >
> > > > > >  static void a6xx_set_hwcg(struct msm_gpu *gpu, bool state)
> > > > > > @@ -588,6 +779,89 @@ static void a6xx_set_ubwc_config(struct msm_gpu *gpu)
> > > > > >                 adreno_gpu->ubwc_config.min_acc_len << 23 | hbb_lo << 21);
> > > > > >  }
> > > > > >
> > > > > > +static void a7xx_patch_pwrup_reglist(struct msm_gpu *gpu)
> > > > > > +{
> > > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > > +     struct adreno_reglist_list reglist[2];
> > > > > > +     void *ptr = a6xx_gpu->pwrup_reglist_ptr;
> > > > > > +     struct cpu_gpu_lock *lock = ptr;
> > > > > > +     u32 *dest = (u32 *)&lock->regs[0];
> > > > > > +     int i, j;
> > > > > > +
> > > > > > +     lock->gpu_req = lock->cpu_req = lock->turn = 0;
> > > > > > +     lock->ifpc_list_len = ARRAY_SIZE(a7xx_ifpc_pwrup_reglist);
> > > > > > +     lock->preemption_list_len = ARRAY_SIZE(a7xx_pwrup_reglist);
> > > > > > +
> > > > > > +     /* Static IFPC-only registers */
> > > > > > +     reglist[0].regs = a7xx_ifpc_pwrup_reglist;
> > > > > > +     reglist[0].count = ARRAY_SIZE(a7xx_ifpc_pwrup_reglist);
> > > > > > +     lock->ifpc_list_len = reglist[0].count;
> > > > > > +
> > > > > > +     /* Static IFPC + preemption registers */
> > > > > > +     reglist[1].regs = a7xx_pwrup_reglist;
> > > > > > +     reglist[1].count = ARRAY_SIZE(a7xx_pwrup_reglist);
> > > > > > +     lock->preemption_list_len = reglist[1].count;
> > > > > > +
> > > > > > +     /*
> > > > > > +      * For each entry in each of the lists, write the offset and the current
> > > > > > +      * register value into the GPU buffer
> > > > > > +      */
> > > > > > +     for (i = 0; i < 2; i++) {
> > > > > > +             const u32 *r = reglist[i].regs;
> > > > > > +
> > > > > > +             for (j = 0; j < reglist[i].count; j++) {
> > > > > > +                     *dest++ = r[j];
> > > > > > +                     *dest++ = gpu_read(gpu, r[j]);
> > > > > > +             }
> > > > > > +     }
> > > > > > +
> > > > > > +     /*
> > > > > > +      * The overall register list is composed of
> > > > > > +      * 1. Static IFPC-only registers
> > > > > > +      * 2. Static IFPC + preemption registers
> > > > > > +      * 3. Dynamic IFPC + preemption registers (ex: perfcounter selects)
> > > > > > +      *
> > > > > > +      * The first two lists are static. Size of these lists are stored as
> > > > > > +      * number of pairs in ifpc_list_len and preemption_list_len
> > > > > > +      * respectively. With concurrent binning, Some of the perfcounter
> > > > > > +      * registers being virtualized, CP needs to know the pipe id to program
> > > > > > +      * the aperture inorder to restore the same. Thus, third list is a
> > > > > > +      * dynamic list with triplets as
> > > > > > +      * (<aperture, shifted 12 bits> <address> <data>), and the length is
> > > > > > +      * stored as number for triplets in dynamic_list_len.
> > > > > > +      */
> > > > > > +     lock->dynamic_list_len = 0;
> > > > > > +}
> > > > > > +
> > > > > > +static int a7xx_preempt_start(struct msm_gpu *gpu)
> > > > > > +{
> > > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > > +     struct msm_ringbuffer *ring = gpu->rb[0];
> > > > > > +
> > > > > > +     if (gpu->nr_rings <= 1)
> > > > > > +             return 0;
> > > > > > +
> > > > > > +     /* Turn CP protection off */
> > > > > > +     OUT_PKT7(ring, CP_SET_PROTECTED_MODE, 1);
> > > > > > +     OUT_RING(ring, 0);
> > > > > > +
> > > > > > +     a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, NULL);
> > > > > > +
> > > > > > +     /* Yield the floor on command completion */
> > > > > > +     OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
> > > > > > +     OUT_RING(ring, 0x00);
> > > > > > +     OUT_RING(ring, 0x00);
> > > > > > +     OUT_RING(ring, 0x01);
> > > > > > +     /* Generate interrupt on preemption completion */
> > > > > > +     OUT_RING(ring, 0x00);
> > > > > > +
> > > > > > +     a6xx_flush(gpu, ring);
> > > > > > +
> > > > > > +     return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
> > > > > > +}
> > > > > > +
> > > > > >  static int a6xx_cp_init(struct msm_gpu *gpu)
> > > > > >  {
> > > > > >       struct msm_ringbuffer *ring = gpu->rb[0];
> > > > > > @@ -619,6 +893,8 @@ static int a6xx_cp_init(struct msm_gpu *gpu)
> > > > > >
> > > > > >  static int a7xx_cp_init(struct msm_gpu *gpu)
> > > > > >  {
> > > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > >       struct msm_ringbuffer *ring = gpu->rb[0];
> > > > > >       u32 mask;
> > > > > >
> > > > > > @@ -626,6 +902,8 @@ static int a7xx_cp_init(struct msm_gpu *gpu)
> > > > > >       OUT_PKT7(ring, CP_THREAD_CONTROL, 1);
> > > > > >       OUT_RING(ring, BIT(27));
> > > > > >
> > > > > > +     a7xx_patch_pwrup_reglist(gpu);
> > > > > > +
> > > > > >       OUT_PKT7(ring, CP_ME_INIT, 7);
> > > > > >
> > > > > >       /* Use multiple HW contexts */
> > > > > > @@ -656,11 +934,11 @@ static int a7xx_cp_init(struct msm_gpu *gpu)
> > > > > >
> > > > > >       /* *Don't* send a power up reg list for concurrent binning (TODO) */
> > > > > >       /* Lo address */
> > > > > > -     OUT_RING(ring, 0x00000000);
> > > > > > +     OUT_RING(ring, lower_32_bits(a6xx_gpu->pwrup_reglist_iova));
> > > > > >       /* Hi address */
> > > > > > -     OUT_RING(ring, 0x00000000);
> > > > > > +     OUT_RING(ring, upper_32_bits(a6xx_gpu->pwrup_reglist_iova));
> > > > > >       /* BIT(31) set => read the regs from the list */
> > > > > > -     OUT_RING(ring, 0x00000000);
> > > > > > +     OUT_RING(ring, BIT(31));
> > > > > >
> > > > > >       a6xx_flush(gpu, ring);
> > > > > >       return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
> > > > > > @@ -784,6 +1062,16 @@ static int a6xx_ucode_load(struct msm_gpu *gpu)
> > > > > >               msm_gem_object_set_name(a6xx_gpu->shadow_bo, "shadow");
> > > > > >       }
> > > > > >
> > > > > > +     a6xx_gpu->pwrup_reglist_ptr = msm_gem_kernel_new(gpu->dev, PAGE_SIZE,
> > > > > > +                                                      MSM_BO_WC  | MSM_BO_MAP_PRIV,
> > > > > > +                                                      gpu->aspace, &a6xx_gpu->pwrup_reglist_bo,
> > > > > > +                                                      &a6xx_gpu->pwrup_reglist_iova);
> > > > > > +
> > > > > > +     if (IS_ERR(a6xx_gpu->pwrup_reglist_ptr))
> > > > > > +             return PTR_ERR(a6xx_gpu->pwrup_reglist_ptr);
> > > > > > +
> > > > > > +     msm_gem_object_set_name(a6xx_gpu->pwrup_reglist_bo, "pwrup_reglist");
> > > > > > +
> > > > > >       return 0;
> > > > > >  }
> > > > > >
> > > > > > @@ -1127,6 +1415,8 @@ static int hw_init(struct msm_gpu *gpu)
> > > > > >       if (a6xx_gpu->shadow_bo) {
> > > > > >               gpu_write64(gpu, REG_A6XX_CP_RB_RPTR_ADDR,
> > > > > >                       shadowptr(a6xx_gpu, gpu->rb[0]));
> > > > > > +             for (unsigned int i = 0; i < gpu->nr_rings; i++)
> > > > > > +                     a6xx_gpu->shadow[i] = 0;
> > > > > >       }
> > > > > >
> > > > > >       /* ..which means "always" on A7xx, also for BV shadow */
> > > > > > @@ -1135,6 +1425,8 @@ static int hw_init(struct msm_gpu *gpu)
> > > > > >                           rbmemptr(gpu->rb[0], bv_rptr));
> > > > > >       }
> > > > > >
> > > > > > +     a6xx_preempt_hw_init(gpu);
> > > > > > +
> > > > > >       /* Always come up on rb 0 */
> > > > > >       a6xx_gpu->cur_ring = gpu->rb[0];
> > > > > >
> > > > > > @@ -1180,6 +1472,10 @@ static int hw_init(struct msm_gpu *gpu)
> > > > > >  out:
> > > > > >       if (adreno_has_gmu_wrapper(adreno_gpu))
> > > > > >               return ret;
> > > > > > +
> > > > > > +     /* Last step - yield the ringbuffer */
> > > > > > +     a7xx_preempt_start(gpu);
> > > > > > +
> > > > > >       /*
> > > > > >        * Tell the GMU that we are done touching the GPU and it can start power
> > > > > >        * management
> > > > > > @@ -1557,8 +1853,13 @@ static irqreturn_t a6xx_irq(struct msm_gpu *gpu)
> > > > > >       if (status & A6XX_RBBM_INT_0_MASK_SWFUSEVIOLATION)
> > > > > >               a7xx_sw_fuse_violation_irq(gpu);
> > > > > >
> > > > > > -     if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS)
> > > > > > +     if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS) {
> > > > > >               msm_gpu_retire(gpu);
> > > > > > +             a6xx_preempt_trigger(gpu);
> > > > > > +     }
> > > > > > +
> > > > > > +     if (status & A6XX_RBBM_INT_0_MASK_CP_SW)
> > > > > > +             a6xx_preempt_irq(gpu);
> > > > > >
> > > > > >       return IRQ_HANDLED;
> > > > > >  }
> > > > > > @@ -2165,6 +2466,8 @@ static const struct adreno_gpu_funcs funcs = {
> > > > > >               .active_ring = a6xx_active_ring,
> > > > > >               .irq = a6xx_irq,
> > > > > >               .destroy = a6xx_destroy,
> > > > > > +             .submitqueue_setup = a6xx_preempt_submitqueue_setup,
> > > > > > +             .submitqueue_close = a6xx_preempt_submitqueue_close,
> > > > > >  #if defined(CONFIG_DRM_MSM_GPU_STATE)
> > > > > >               .show = a6xx_show,
> > > > > >  #endif
> > > > > > @@ -2331,6 +2634,8 @@ struct msm_gpu *a6xx_gpu_init(struct drm_device *dev)
> > > > > >                               a6xx_fault_handler);
> > > > > >
> > > > > >       a6xx_calc_ubwc_config(adreno_gpu);
> > > > > > +     /* Set up the preemption specific bits and pieces for each ringbuffer */
> > > > > > +     a6xx_preempt_init(gpu);
> > > > > >
> > > > > >       return gpu;
> > > > > >  }
> > > > > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > > > > > index e3e5c53ae8af..652e49f01428 100644
> > > > > > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > > > > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> > > > > > @@ -12,6 +12,31 @@
> > > > > >
> > > > > >  extern bool hang_debug;
> > > > > >
> > > > > > +struct cpu_gpu_lock {
> > > > > > +     uint32_t gpu_req;
> > > > > > +     uint32_t cpu_req;
> > > > > > +     uint32_t turn;
> > > > > > +     union {
> > > > > > +             struct {
> > > > > > +                     uint16_t list_length;
> > > > > > +                     uint16_t list_offset;
> > > > > > +             };
> > > > > > +             struct {
> > > > > > +                     uint8_t ifpc_list_len;
> > > > > > +                     uint8_t preemption_list_len;
> > > > > > +                     uint16_t dynamic_list_len;
> > > > > > +             };
> > > > > > +     };
> > > > > > +     uint64_t regs[62];
> > > > > > +};
> > > > > > +
> > > > > > +struct adreno_reglist_list {
> > > > > > +     /** @reg: List of register **/
> > > > > > +     const u32 *regs;
> > > > > > +     /** @count: Number of registers in the list **/
> > > > > > +     u32 count;
> > > > > > +};
> > > > > > +
> > > > > >  /**
> > > > > >   * struct a6xx_info - a6xx specific information from device table
> > > > > >   *
> > > > > > @@ -31,6 +56,24 @@ struct a6xx_gpu {
> > > > > >       uint64_t sqe_iova;
> > > > > >
> > > > > >       struct msm_ringbuffer *cur_ring;
> > > > > > +     struct msm_ringbuffer *next_ring;
> > > > > > +
> > > > > > +     struct drm_gem_object *preempt_bo[MSM_GPU_MAX_RINGS];
> > > > > > +     void *preempt[MSM_GPU_MAX_RINGS];
> > > > > > +     uint64_t preempt_iova[MSM_GPU_MAX_RINGS];
> > > > > > +     uint32_t last_seqno[MSM_GPU_MAX_RINGS];
> > > > > > +
> > > > > > +     atomic_t preempt_state;
> > > > > > +     spinlock_t eval_lock;
> > > > > > +     struct timer_list preempt_timer;
> > > > > > +
> > > > > > +     unsigned int preempt_level;
> > > > > > +     bool uses_gmem;
> > > > > > +     bool skip_save_restore;
> > > > > > +
> > > > > > +     struct drm_gem_object *scratch_bo;
> > > > > > +     void *scratch_ptr;
> > > > > > +     uint64_t scratch_iova;
> > > > > >
> > > > > >       struct a6xx_gmu gmu;
> > > > > >
> > > > > > @@ -38,6 +81,10 @@ struct a6xx_gpu {
> > > > > >       uint64_t shadow_iova;
> > > > > >       uint32_t *shadow;
> > > > > >
> > > > > > +     struct drm_gem_object *pwrup_reglist_bo;
> > > > > > +     void *pwrup_reglist_ptr;
> > > > > > +     uint64_t pwrup_reglist_iova;
> > > > > > +
> > > > > >       bool has_whereami;
> > > > > >
> > > > > >       void __iomem *llc_mmio;
> > > > > > @@ -49,6 +96,108 @@ struct a6xx_gpu {
> > > > > >
> > > > > >  #define to_a6xx_gpu(x) container_of(x, struct a6xx_gpu, base)
> > > > > >
> > > > > > +#define SCRATCH_USER_CTX_IOVA(ring_id, a6xx_gpu) \
> > > > > > +     (a6xx_gpu->scratch_iova + (ring_id * sizeof(uint64_t)))
> > > > > > +
> > > > > > +/*
> > > > > > + * In order to do lockless preemption we use a simple state machine to progress
> > > > > > + * through the process.
> > > > > > + *
> > > > > > + * PREEMPT_NONE - no preemption in progress.  Next state START.
> > > > > > + * PREEMPT_START - The trigger is evaluating if preemption is possible. Next
> > > > > > + * states: TRIGGERED, NONE
> > > > > > + * PREEMPT_FINISH - An intermediate state before moving back to NONE. Next
> > > > > > + * state: NONE.
> > > > > > + * PREEMPT_TRIGGERED: A preemption has been executed on the hardware. Next
> > > > > > + * states: FAULTED, PENDING
> > > > > > + * PREEMPT_FAULTED: A preemption timed out (never completed). This will trigger
> > > > > > + * recovery.  Next state: N/A
> > > > > > + * PREEMPT_PENDING: Preemption complete interrupt fired - the callback is
> > > > > > + * checking the success of the operation. Next state: FAULTED, NONE.
> > > > > > + */
> > > > > > +
> > > > > > +enum a6xx_preempt_state {
> > > > > > +     PREEMPT_NONE = 0,
> > > > > > +     PREEMPT_START,
> > > > > > +     PREEMPT_FINISH,
> > > > > > +     PREEMPT_TRIGGERED,
> > > > > > +     PREEMPT_FAULTED,
> > > > > > +     PREEMPT_PENDING,
> > > > > > +};
> > > > > > +
> > > > > > +/*
> > > > > > + * struct a6xx_preempt_record is a shared buffer between the microcode and the
> > > > > > + * CPU to store the state for preemption. The record itself is much larger
> > > > > > + * (2112k) but most of that is used by the CP for storage.
> > > > > > + *
> > > > > > + * There is a preemption record assigned per ringbuffer. When the CPU triggers a
> > > > > > + * preemption, it fills out the record with the useful information (wptr, ring
> > > > > > + * base, etc) and the microcode uses that information to set up the CP following
> > > > > > + * the preemption.  When a ring is switched out, the CP will save the ringbuffer
> > > > > > + * state back to the record. In this way, once the records are properly set up
> > > > > > + * the CPU can quickly switch back and forth between ringbuffers by only
> > > > > > + * updating a few registers (often only the wptr).
> > > > > > + *
> > > > > > + * These are the CPU aware registers in the record:
> > > > > > + * @magic: Must always be 0xAE399D6EUL
> > > > > > + * @info: Type of the record - written 0 by the CPU, updated by the CP
> > > > > > + * @errno: preemption error record
> > > > > > + * @data: Data field in YIELD and SET_MARKER packets, Written and used by CP
> > > > > > + * @cntl: Value of RB_CNTL written by CPU, save/restored by CP
> > > > > > + * @rptr: Value of RB_RPTR written by CPU, save/restored by CP
> > > > > > + * @wptr: Value of RB_WPTR written by CPU, save/restored by CP
> > > > > > + * @_pad: Reserved/padding
> > > > > > + * @rptr_addr: Value of RB_RPTR_ADDR_LO|HI written by CPU, save/restored by CP
> > > > > > + * @rbase: Value of RB_BASE written by CPU, save/restored by CP
> > > > > > + * @counter: GPU address of the storage area for the preemption counters
> > > > > > + */
> > > > > > +struct a6xx_preempt_record {
> > > > > > +     u32 magic;
> > > > > > +     u32 info;
> > > > > > +     u32 errno;
> > > > > > +     u32 data;
> > > > > > +     u32 cntl;
> > > > > > +     u32 rptr;
> > > > > > +     u32 wptr;
> > > > > > +     u32 _pad;
> > > > > > +     u64 rptr_addr;
> > > > > > +     u64 rbase;
> > > > > > +     u64 counter;
> > > > > > +     u64 bv_rptr_addr;
> > > > > > +};
> > > > > > +
> > > > > > +#define A6XX_PREEMPT_RECORD_MAGIC 0xAE399D6EUL
> > > > > > +
> > > > > > +#define PREEMPT_RECORD_SIZE_FALLBACK(size) \
> > > > > > +     ((size) == 0 ? 4192 * SZ_1K : (size))
> > > > > > +
> > > > > > +#define PREEMPT_OFFSET_SMMU_INFO 0
> > > > > > +#define PREEMPT_OFFSET_PRIV_NON_SECURE (PREEMPT_OFFSET_SMMU_INFO + 4096)
> > > > > > +#define PREEMPT_OFFSET_PRIV_SECURE(size) \
> > > > > > +     (PREEMPT_OFFSET_PRIV_NON_SECURE + PREEMPT_RECORD_SIZE_FALLBACK(size))
> > > > > > +#define PREEMPT_SIZE(size) \
> > > > > > +     (PREEMPT_OFFSET_PRIV_SECURE(size) + PREEMPT_RECORD_SIZE_FALLBACK(size))
> > > > > > +
> > > > > > +/*
> > > > > > + * The preemption counter block is a storage area for the value of the
> > > > > > + * preemption counters that are saved immediately before context switch. We
> > > > > > + * append it on to the end of the allocation for the preemption record.
> > > > > > + */
> > > > > > +#define A6XX_PREEMPT_COUNTER_SIZE (16 * 4)
> > > > > > +
> > > > > > +#define A6XX_PREEMPT_USER_RECORD_SIZE (192 * 1024)
> > > > > > +
> > > > > > +struct a7xx_cp_smmu_info {
> > > > > > +     u32 magic;
> > > > > > +     u32 _pad4;
> > > > > > +     u64 ttbr0;
> > > > > > +     u32 asid;
> > > > > > +     u32 context_idr;
> > > > > > +     u32 context_bank;
> > > > > > +};
> > > > > > +
> > > > > > +#define GEN7_CP_SMMU_INFO_MAGIC 0x241350d5UL
> > > > > > +
> > > > > >  /*
> > > > > >   * Given a register and a count, return a value to program into
> > > > > >   * REG_CP_PROTECT_REG(n) - this will block both reads and writes for
> > > > > > @@ -106,6 +255,25 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
> > > > > >  int a6xx_gmu_wrapper_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
> > > > > >  void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu);
> > > > > >
> > > > > > +void a6xx_preempt_init(struct msm_gpu *gpu);
> > > > > > +void a6xx_preempt_hw_init(struct msm_gpu *gpu);
> > > > > > +void a6xx_preempt_trigger(struct msm_gpu *gpu);
> > > > > > +void a6xx_preempt_irq(struct msm_gpu *gpu);
> > > > > > +void a6xx_preempt_fini(struct msm_gpu *gpu);
> > > > > > +int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
> > > > > > +             struct msm_gpu_submitqueue *queue);
> > > > > > +void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
> > > > > > +             struct msm_gpu_submitqueue *queue);
> > > > > > +
> > > > > > +/* Return true if we are in a preempt state */
> > > > > > +static inline bool a6xx_in_preempt(struct a6xx_gpu *a6xx_gpu)
> > > > > > +{
> > > > > > +     int preempt_state = atomic_read(&a6xx_gpu->preempt_state);
> > > > > > +
> > > > > > +     return !(preempt_state == PREEMPT_NONE ||
> > > > > > +                     preempt_state == PREEMPT_FINISH);
> > > > > > +}
> > > > > > +
> > > > > >  void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp,
> > > > > >                      bool suspended);
> > > > > >  unsigned long a6xx_gmu_get_freq(struct msm_gpu *gpu);
> > > > > > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_preempt.c b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
> > > > > > new file mode 100644
> > > > > > index 000000000000..0d402a3bcf5a
> > > > > > --- /dev/null
> > > > > > +++ b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
> > > > > > @@ -0,0 +1,434 @@
> > > > > > +// SPDX-License-Identifier: GPL-2.0
> > > > > > +/* Copyright (c) 2018, The Linux Foundation. All rights reserved. */
> > > > > > +/* Copyright (c) 2023 Collabora, Ltd. */
> > > > > > +/* Copyright (c) 2024 Valve Corporation */
> > > > > > +
> > > > > > +#include "msm_gem.h"
> > > > > > +#include "a6xx_gpu.h"
> > > > > > +#include "a6xx_gmu.xml.h"
> > > > > > +#include "msm_mmu.h"
> > > > > > +
> > > > > > +#define FENCE_STATUS_WRITEDROPPED0_MASK 0x1
> > > > > > +#define FENCE_STATUS_WRITEDROPPED1_MASK 0x2
> > > > > > +
> > > > > > +/*
> > > > > > + * Try to transition the preemption state from old to new. Return
> > > > > > + * true on success or false if the original state wasn't 'old'
> > > > > > + */
> > > > > > +static inline bool try_preempt_state(struct a6xx_gpu *a6xx_gpu,
> > > > > > +             enum a6xx_preempt_state old, enum a6xx_preempt_state new)
> > > > > > +{
> > > > > > +     enum a6xx_preempt_state cur = atomic_cmpxchg(&a6xx_gpu->preempt_state,
> > > > > > +             old, new);
> > > > > > +
> > > > > > +     return (cur == old);
> > > > > > +}
> > > > > > +
> > > > > > +/*
> > > > > > + * Force the preemption state to the specified state.  This is used in cases
> > > > > > + * where the current state is known and won't change
> > > > > > + */
> > > > > > +static inline void set_preempt_state(struct a6xx_gpu *gpu,
> > > > > > +             enum a6xx_preempt_state new)
> > > > > > +{
> > > > > > +     /*
> > > > > > +      * preempt_state may be read by other cores trying to trigger a
> > > > > > +      * preemption or in the interrupt handler so barriers are needed
> > > > > > +      * before...
> > > > > > +      */
> > > > > > +     smp_mb__before_atomic();
> > > > > > +     atomic_set(&gpu->preempt_state, new);
> > > > > > +     /* ... and after*/
> > > > > > +     smp_mb__after_atomic();
> > > > > > +}
> > > > > > +
> > > > > > +/* Write the most recent wptr for the given ring into the hardware */
> > > > > > +static inline void update_wptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> > > > > > +{
> > > > > > +     unsigned long flags;
> > > > > > +     uint32_t wptr, cur_wptr;
> > > > > > +
> > > > > > +     if (!ring)
> > > > > > +             return;
> > > > > > +
> > > > > > +     spin_lock_irqsave(&ring->preempt_lock, flags);
> > > > > > +
> > > > > > +     if (ring->skip_inline_wptr) {
> > > > > > +             wptr = get_wptr(ring);
> > > > > > +
> > > > > > +             gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
> > > > > > +
> > > > > > +             ring->skip_inline_wptr = false;
> > > > > > +     }
> > > > > > +
> > > > > > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > > > > +}
> > > > > > +
> > > > > > +/* Return the highest priority ringbuffer with something in it */
> > > > > > +static struct msm_ringbuffer *get_next_ring(struct msm_gpu *gpu)
> > > > > > +{
> > > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > > +
> > > > > > +     unsigned long flags;
> > > > > > +     int i;
> > > > > > +
> > > > > > +     for (i = 0; i < gpu->nr_rings; i++) {
> > > > > > +             bool empty;
> > > > > > +             struct msm_ringbuffer *ring = gpu->rb[i];
> > > > > > +
> > > > > > +             spin_lock_irqsave(&ring->preempt_lock, flags);
> > > > > > +             empty = (get_wptr(ring) == gpu->funcs->get_rptr(gpu, ring));
> > > > > > +             if (!empty && ring == a6xx_gpu->cur_ring)
> > > > > > +                     empty = ring->memptrs->fence == a6xx_gpu->last_seqno[i];
> > > > > > +             spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > > > > +
> > > > > > +             if (!empty)
> > > > > > +                     return ring;
> > > > > > +     }
> > > > > > +
> > > > > > +     return NULL;
> > > > > > +}
> > > > > > +
> > > > > > +static void a6xx_preempt_timer(struct timer_list *t)
> > > > > > +{
> > > > > > +     struct a6xx_gpu *a6xx_gpu = from_timer(a6xx_gpu, t, preempt_timer);
> > > > > > +     struct msm_gpu *gpu = &a6xx_gpu->base.base;
> > > > > > +     struct drm_device *dev = gpu->dev;
> > > > > > +
> > > > > > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_FAULTED))
> > > > > > +             return;
> > > > > > +
> > > > > > +     dev_err(dev->dev, "%s: preemption timed out\n", gpu->name);
> > > > > > +     kthread_queue_work(gpu->worker, &gpu->recover_work);
> > > > > > +}
> > > > > > +
> > > > > > +void a6xx_preempt_irq(struct msm_gpu *gpu)
> > > > > > +{
> > > > > > +     uint32_t status;
> > > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > > +     struct drm_device *dev = gpu->dev;
> > > > > > +
> > > > > > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_PENDING))
> > > > > > +             return;
> > > > > > +
> > > > > > +     /* Delete the preemption watchdog timer */
> > > > > > +     del_timer(&a6xx_gpu->preempt_timer);
> > > > > > +
> > > > > > +     /*
> > > > > > +      * The hardware should be setting the stop bit of CP_CONTEXT_SWITCH_CNTL
> > > > > > +      * to zero before firing the interrupt, but there is a non zero chance
> > > > > > +      * of a hardware condition or a software race that could set it again
> > > > > > +      * before we have a chance to finish. If that happens, log and go for
> > > > > > +      * recovery
> > > > > > +      */
> > > > > > +     status = gpu_read(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL);
> > > > > > +     if (unlikely(status & 0x1)) {
> > > > > > +             DRM_DEV_ERROR(&gpu->pdev->dev,
> > > > > > +                                       "!!!!!!!!!!!!!!!! preemption faulted !!!!!!!!!!!!!! irq\n");
> > > > > > +             set_preempt_state(a6xx_gpu, PREEMPT_FAULTED);
> > > > > > +             dev_err(dev->dev, "%s: Preemption failed to complete\n",
> > > > > > +                     gpu->name);
> > > > > > +             kthread_queue_work(gpu->worker, &gpu->recover_work);
> > > > > > +             return;
> > > > > > +     }
> > > > > > +
> > > > > > +     a6xx_gpu->cur_ring = a6xx_gpu->next_ring;
> > > > > > +     a6xx_gpu->next_ring = NULL;
> > > > > > +
> > > > > > +     /* Make sure the write to cur_ring is posted before the change in state */
> > > > > > +     wmb();
> > > > > > +
> > > > > > +     set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
> > > > > > +
> > > > > > +     update_wptr(gpu, a6xx_gpu->cur_ring);
> > > > > > +
> > > > > > +     set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > > > > > +
> > > > > > +     /*
> > > > > > +      * Retrigger preemption to avoid a deadlock that might occur when preemption
> > > > > > +      * is skipped due to it being already in flight when requested.
> > > > > > +      */
> > > > > > +     a6xx_preempt_trigger(gpu);
> > > > > > +}
> > > > > > +
> > > > > > +void a6xx_preempt_hw_init(struct msm_gpu *gpu)
> > > > > > +{
> > > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > > +     int i;
> > > > > > +
> > > > > > +     /* No preemption if we only have one ring */
> > > > > > +     if (gpu->nr_rings == 1)
> > > > > > +             return;
> > > > > > +
> > > > > > +     for (i = 0; i < gpu->nr_rings; i++) {
> > > > > > +             struct a6xx_preempt_record *record_ptr =
> > > > > > +                     a6xx_gpu->preempt[i] + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > > > > > +             record_ptr->wptr = 0;
> > > > > > +             record_ptr->rptr = 0;
> > > > > > +             record_ptr->rptr_addr = shadowptr(a6xx_gpu, gpu->rb[i]);
> > > > > > +             record_ptr->info = 0;
> > > > > > +             record_ptr->data = 0;
> > > > > > +             record_ptr->rbase = gpu->rb[i]->iova;
> > > > > > +     }
> > > > > > +
> > > > > > +     /* Write a 0 to signal that we aren't switching pagetables */
> > > > > > +     gpu_write64(gpu, REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO, 0);
> > > > > > +
> > > > > > +     /* Enable the GMEM save/restore feature for preemption */
> > > > > > +     gpu_write(gpu, REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE, 0x1);
> > > > > > +
> > > > > > +     /* Reset the preemption state */
> > > > > > +     set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > > > > > +
> > > > > > +     spin_lock_init(&a6xx_gpu->eval_lock);
> > > > > > +
> > > > > > +     /* Always come up on rb 0 */
> > > > > > +     a6xx_gpu->cur_ring = gpu->rb[0];
> > > > > > +}
> > > > > > +
> > > > > > +void a6xx_preempt_trigger(struct msm_gpu *gpu)
> > > > > > +{
> > > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > > +     u64 preempt_offset_priv_secure;
> > > > > > +     unsigned long flags;
> > > > > > +     struct msm_ringbuffer *ring;
> > > > > > +     uint64_t user_ctx_iova;
> > > > > > +     unsigned int cntl;
> > > > > > +
> > > > > > +     if (gpu->nr_rings == 1)
> > > > > > +             return;
> > > > > > +
> > > > > > +     /*
> > > > > > +      * Lock to make sure another thread attempting preemption doesn't skip it
> > > > > > +      * while we are still evaluating the next ring. This makes sure the other
> > > > > > +      * thread does start preemption if we abort it and avoids a soft lock.
> > > > > > +      */
> > > > > > +     spin_lock_irqsave(&a6xx_gpu->eval_lock, flags);
> > > > > > +
> > > > > > +     /*
> > > > > > +      * Try to start preemption by moving from NONE to START. If
> > > > > > +      * unsuccessful, a preemption is already in flight
> > > > > > +      */
> > > > > > +     if (!try_preempt_state(a6xx_gpu, PREEMPT_NONE, PREEMPT_START)) {
> > > > > > +             spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > > > > > +             return;
> > > > > > +     }
> > > > > > +
> > > > > > +     cntl = (((a6xx_gpu->preempt_level << 6) & 0xC0) |
> > > > > > +             ((a6xx_gpu->skip_save_restore << 9) & 0x200) |
> > > > > > +             ((a6xx_gpu->uses_gmem << 8) & 0x100) | 0x1);
> > > > > > +
> > > > > > +     /* Get the next ring to preempt to */
> > > > > > +     ring = get_next_ring(gpu);
> > > > > > +
> > > > > > +     /*
> > > > > > +      * If no ring is populated or the highest priority ring is the current
> > > > > > +      * one do nothing except to update the wptr to the latest and greatest
> > > > > > +      */
> > > > > > +     if (!ring || (a6xx_gpu->cur_ring == ring)) {
> > > > > > +             set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
> > > > > > +             update_wptr(gpu, a6xx_gpu->cur_ring);
> > > > > > +             set_preempt_state(a6xx_gpu, PREEMPT_NONE);
> > > > > > +             spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > > > > > +             return;
> > > > > > +     }
> > > > > > +
> > > > > > +     spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
> > > > > > +
> > > > > > +     spin_lock_irqsave(&ring->preempt_lock, flags);
> > > > > > +
> > > > > > +     struct a7xx_cp_smmu_info *smmu_info_ptr =
> > > > > > +             a6xx_gpu->preempt[ring->id] + PREEMPT_OFFSET_SMMU_INFO;
> > > > > > +     struct a6xx_preempt_record *record_ptr =
> > > > > > +             a6xx_gpu->preempt[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > > > > > +     u64 ttbr0 = ring->memptrs->ttbr0;
> > > > > > +     u32 context_idr = ring->memptrs->context_idr;
> > > > > > +
> > > > > > +     smmu_info_ptr->ttbr0 = ttbr0;
> > > > > > +     smmu_info_ptr->context_idr = context_idr;
> > > > > > +     record_ptr->wptr = get_wptr(ring);
> > > > > > +
> > > > > > +     /*
> > > > > > +      * The GPU will write the wptr we set above when we preempt. Reset
> > > > > > +      * skip_inline_wptr to make sure that we don't write WPTR to the same
> > > > > > +      * thing twice. It's still possible subsequent submissions will update
> > > > > > +      * wptr again, in which case they will set the flag to true. This has
> > > > > > +      * to be protected by the lock for setting the flag and updating wptr
> > > > > > +      * to be atomic.
> > > > > > +      */
> > > > > > +     ring->skip_inline_wptr = false;
> > > > > > +
> > > > > > +     spin_unlock_irqrestore(&ring->preempt_lock, flags);
> > > > > > +
> > > > > > +     gpu_write64(gpu,
> > > > > > +             REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO,
> > > > > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_SMMU_INFO);
> > > > > > +
> > > > > > +     gpu_write64(gpu,
> > > > > > +             REG_A6XX_CP_CONTEXT_SWITCH_PRIV_NON_SECURE_RESTORE_ADDR,
> > > > > > +             a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE);
> > > > > > +
> > > > > > +     preempt_offset_priv_secure =
> > > > > > +             PREEMPT_OFFSET_PRIV_SECURE(adreno_gpu->info->preempt_record_size);
> > > > > > +     gpu_write64(gpu,
> > > > > > +             REG_A6XX_CP_CONTEXT_SWITCH_PRIV_SECURE_RESTORE_ADDR,
> > > > > > +             a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure);
> > > > > > +
> > > > > > +     /*
> > > > > > +      * Use the user context iova from the scratch memory that the CP may
> > > > > > +      * have written as part of the ring switch out.
> > > > > > +      */
> > > > > > +     user_ctx_iova = *((uint64_t *)a6xx_gpu->scratch_ptr + ring->id);
> > > > > > +
> > > > > > +     gpu_write64(gpu,
> > > > > > +             REG_A6XX_CP_CONTEXT_SWITCH_NON_PRIV_RESTORE_ADDR,
> > > > > > +             user_ctx_iova);
> > > > > > +
> > > > > > +     a6xx_gpu->next_ring = ring;
> > > > > > +
> > > > > > +     /* Start a timer to catch a stuck preemption */
> > > > > > +     mod_timer(&a6xx_gpu->preempt_timer, jiffies + msecs_to_jiffies(10000));
> > > > > > +
> > > > > > +     /* Set the preemption state to triggered */
> > > > > > +     set_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED);
> > > > > > +
> > > > > > +     /* Make sure any previous writes to WPTR are posted */
> > > > > > +     gpu_read(gpu, REG_A6XX_CP_RB_WPTR);
> > > > > > +
> > > > > > +     /* Make sure everything is written before hitting the button */
> > > > > > +     wmb();
> > > > > > +
> > > > > > +     /* Trigger the preemption */
> > > > > > +     gpu_write(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL, cntl);
> > > > > > +}
> > > > > > +
> > > > > > +static int preempt_init_ring(struct a6xx_gpu *a6xx_gpu,
> > > > > > +             struct msm_ringbuffer *ring)
> > > > > > +{
> > > > > > +     struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
> > > > > > +     struct msm_gpu *gpu = &adreno_gpu->base;
> > > > > > +     struct drm_gem_object *bo = NULL;
> > > > > > +     phys_addr_t ttbr;
> > > > > > +     u64 iova = 0;
> > > > > > +     void *ptr;
> > > > > > +     int asid;
> > > > > > +
> > > > > > +     ptr = msm_gem_kernel_new(gpu->dev,
> > > > > > +             PREEMPT_SIZE(adreno_gpu->info->preempt_record_size),
> > > > > > +             MSM_BO_WC | MSM_BO_MAP_PRIV, gpu->aspace, &bo, &iova);
> > > > > > +
> > > > > > +     memset(ptr, 0, PREEMPT_SIZE(adreno_gpu->info->preempt_record_size));
> > > > > > +
> > > > > > +     if (IS_ERR(ptr))
> > > > > > +             return PTR_ERR(ptr);
> > > > > > +
> > > > > > +     a6xx_gpu->preempt_bo[ring->id] = bo;
> > > > > > +     a6xx_gpu->preempt_iova[ring->id] = iova;
> > > > > > +     a6xx_gpu->preempt[ring->id] = ptr;
> > > > > > +
> > > > > > +     struct a7xx_cp_smmu_info *smmu_info_ptr = ptr + PREEMPT_OFFSET_SMMU_INFO;
> > > > > > +     struct a6xx_preempt_record *record_ptr = ptr + PREEMPT_OFFSET_PRIV_NON_SECURE;
> > > > > > +
> > > > > > +     msm_iommu_pagetable_params(gpu->aspace->mmu, &ttbr, &asid);
> > > > > > +
> > > > > > +     smmu_info_ptr->magic = GEN7_CP_SMMU_INFO_MAGIC;
> > > > > > +     smmu_info_ptr->ttbr0 = ttbr;
> > > > > > +     smmu_info_ptr->asid = 0xdecafbad;
> > > > > > +     smmu_info_ptr->context_idr = 0;
> > > > > > +
> > > > > > +     /* Set up the defaults on the preemption record */
> > > > > > +     record_ptr->magic = A6XX_PREEMPT_RECORD_MAGIC;
> > > > > > +     record_ptr->info = 0;
> > > > > > +     record_ptr->data = 0;
> > > > > > +     record_ptr->rptr = 0;
> > > > > > +     record_ptr->wptr = 0;
> > > > > > +     record_ptr->cntl = MSM_GPU_RB_CNTL_DEFAULT;
> > > > > > +     record_ptr->rbase = ring->iova;
> > > > > > +     record_ptr->counter = 0;
> > > > > > +     record_ptr->bv_rptr_addr = rbmemptr(ring, bv_rptr);
> > > > > > +
> > > > > > +     return 0;
> > > > > > +}
> > > > > > +
> > > > > > +void a6xx_preempt_fini(struct msm_gpu *gpu)
> > > > > > +{
> > > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > > +     int i;
> > > > > > +
> > > > > > +     for (i = 0; i < gpu->nr_rings; i++)
> > > > > > +             msm_gem_kernel_put(a6xx_gpu->preempt_bo[i], gpu->aspace);
> > > > > > +}
> > > > > > +
> > > > > > +void a6xx_preempt_init(struct msm_gpu *gpu)
> > > > > > +{
> > > > > > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > > > > > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > > > > > +     int i;
> > > > > > +
> > > > > > +     /* No preemption if we only have one ring */
> > > > > > +     if (gpu->nr_rings <= 1)
> > > > > > +             return;
> > > > > > +
> > > > > > +     for (i = 0; i < gpu->nr_rings; i++) {
> > > > > > +             if (preempt_init_ring(a6xx_gpu, gpu->rb[i]))
> > > > > > +                     goto fail;
> > > > > > +     }
> > > > > > +
> > > > > > +     /* TODO: make this configurable? */
> > > > > > +     a6xx_gpu->preempt_level = 1;
> > > > > > +     a6xx_gpu->uses_gmem = 1;
> > > > > > +     a6xx_gpu->skip_save_restore = 1;
> > > > > > +
> > > > > > +     a6xx_gpu->scratch_ptr  = msm_gem_kernel_new(gpu->dev,
> > > > > > +                     gpu->nr_rings * sizeof(uint64_t), MSM_BO_WC,
> > > > > > +                     gpu->aspace, &a6xx_gpu->scratch_bo,
> > > > > > +                     &a6xx_gpu->scratch_iova);
> > > > > > +
> > > > > > +     if (IS_ERR(a6xx_gpu->scratch_ptr))
> > > > > > +             goto fail;
> > > > > > +
> > > > > > +     timer_setup(&a6xx_gpu->preempt_timer, a6xx_preempt_timer, 0);
> > > > > > +
> > > > > > +     return;
> > > > > > +fail:
> > > > > > +     /*
> > > > > > +      * On any failure our adventure is over. Clean up and
> > > > > > +      * set nr_rings to 1 to force preemption off
> > > > > > +      */
> > > > > > +     a6xx_preempt_fini(gpu);
> > > > > > +     gpu->nr_rings = 1;
> > > > > > +
> > > > > > +     return;
> > > > > > +}
> > > > > > +
> > > > > > +void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
> > > > > > +             struct msm_gpu_submitqueue *queue)
> > > > > > +{
> > > > > > +     if (!queue->bo)
> > > > > > +             return;
> > > > > > +
> > > > > > +     msm_gem_kernel_put(queue->bo, gpu->aspace);
> > > > > > +}
> > > > > > +
> > > > > > +int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
> > > > > > +             struct msm_gpu_submitqueue *queue)
> > > > > > +{
> > > > > > +     void *ptr;
> > > > > > +
> > > > > > +     /*
> > > > > > +      * Create a per submitqueue buffer for the CP to save and restore user
> > > > > > +      * specific information such as the VPC streamout data.
> > > > > > +      */
> > > > > > +     ptr = msm_gem_kernel_new(gpu->dev, A6XX_PREEMPT_USER_RECORD_SIZE,
> > > > > > +                     MSM_BO_WC, gpu->aspace, &queue->bo, &queue->bo_iova);
> > > > > > +
> > > > > > +     if (IS_ERR(ptr))
> > > > > > +             return PTR_ERR(ptr);
> > > > > > +
> > > > > > +     return 0;
> > > > > > +}
> > > > > > diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.h b/drivers/gpu/drm/msm/msm_ringbuffer.h
> > > > > > index 40791b2ade46..7dde6a312511 100644
> > > > > > --- a/drivers/gpu/drm/msm/msm_ringbuffer.h
> > > > > > +++ b/drivers/gpu/drm/msm/msm_ringbuffer.h
> > > > > > @@ -36,6 +36,7 @@ struct msm_rbmemptrs {
> > > > > >
> > > > > >       volatile struct msm_gpu_submit_stats stats[MSM_GPU_SUBMIT_STATS_COUNT];
> > > > > >       volatile u64 ttbr0;
> > > > > > +     volatile u32 context_idr;
> > > > > >  };
> > > > > >
> > > > > >  struct msm_cp_state {
> > > > > > @@ -100,6 +101,12 @@ struct msm_ringbuffer {
> > > > > >        * preemption.  Can be aquired from irq context.
> > > > > >        */
> > > > > >       spinlock_t preempt_lock;
> > > > > > +
> > > > > > +     /*
> > > > > > +      * Whether we skipped writing wptr and it needs to be updated in the
> > > > > > +      * future when the ring becomes current.
> > > > > > +      */
> > > > > > +     bool skip_inline_wptr;
> > > > > >  };
> > > > > >
> > > > > >  struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int id,
> > > > > >
> > > > > > --
> > > > > > 2.46.0
> > > > > >
> > > > > >

Antonino Maniscalco Aug. 27, 2024, 8:25 p.m. UTC | #12

On 8/27/24 9:48 PM, Akhil P Oommen wrote:
> On Fri, Aug 23, 2024 at 10:23:48AM +0100, Connor Abbott wrote:
>> On Fri, Aug 23, 2024 at 10:21 AM Connor Abbott <[e-mail]> wrote:
>>>
>>> On Thu, Aug 22, 2024 at 9:06 PM Akhil P Oommen <[e-mail]> wrote:
>>>>
>>>> On Wed, Aug 21, 2024 at 05:02:56PM +0100, Connor Abbott wrote:
>>>>> On Mon, Aug 19, 2024 at 9:09 PM Akhil P Oommen <[e-mail]> wrote:
>>>>>>
>>>>>> On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
>>>>>>> This patch implements preemption feature for A6xx targets, this allows
>>>>>>> the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
>>>>>>> hardware as such supports multiple levels of preemption granularities,
>>>>>>> ranging from coarse grained(ringbuffer level) to a more fine grained
>>>>>>> such as draw-call level or a bin boundary level preemption. This patch
>>>>>>> enables the basic preemption level, with more fine grained preemption
>>>>>>> support to follow.
>>>>>>>
>>>>>>> Signed-off-by: Sharat Masetty <[e-mail]>
>>>>>>> Signed-off-by: Antonino Maniscalco <[e-mail]>
>>>>>>> ---
>>>>>>
>>>>>> No postamble packets which resets perfcounters? It is necessary. Also, I
>>>>>> think we should disable preemption during profiling like we disable slumber.
>>>>>>
>>>>>> -Akhil.
>>>>>
>>>>> I don't see anything in kgsl which disables preemption during
>>>>> profiling. It disables resetting perfcounters when doing system-wide
>>>>> profiling, like freedreno, and in that case I assume preempting is
>>>>> fine because the system profiler has a complete view of everything and
>>>>> should "see" preemptions through the traces. For something like
>>>>> VK_KHR_performance_query I suppose we'd want to disable preemption
>>>>> because we disable saving/restoring perf counters, but that has to
>>>>> happen in userspace because the kernel doesn't know what userspace
>>>>> does.
>>>>>
>>>>
>>>> KGSL does some sort of arbitration of perfcounter configurations and
>>>> adds the select/enablement reg configuration as part of dynamic
>>>> power up register list which we are not doing here. Is this something
>>>> you are taking care of from userspace via preamble?
>>>>
>>>> -Akhil
>>>
>>> I don't think we have to take care of that in userspace, because Mesa
>>> will always configure the counter registers before reading them in the
>>> same submission, and if it gets preempted in the meantime then we're
>>> toast anyways (due to not saving/restoring perf counters). kgsl sets
>>> them from userspace, which is why it has to do something to set them
>>
>> Sorry, should be "kgsl sets them from the kernel".
>>
>>> after IFPC slumber or a context switch when the HW state is gone.
>>> Also, because the upstream approach doesn't play nicely with system
>>> profilers like perfetto, VK_KHR_performance_query is hidden by default
>>> behind a debug flag in turnip. So there's already an element of "this
>>> is unsupported, you have to know what you're doing to use it."
> 
> But when you have composition on GPU enabled, there will be very frequent
> preemption. And I don't know how usable profiling tools will be in that
> case unless you disable preemption with a Mesa debug flag. But for that
> to work, all existing submitqueues should be destroyed and recreated.
> 
> So I was thinking that we can use the sysprof propertry to force L0
> preemption from kernel.
> 
> -Akhil.
> 

Right but when using a system profiler I imagined the expectation would 
be to be able to understand how applications and compositor interact. An 
use case could be measuring latency and understanding what contributes 
to it. That is actually the main reason I added traces for preemption. 
Disabling preemption would make it less useful for this type of 
analysis. Did you have an use case in mind for a system profiler that 
would benefit from disabling preemption and that is not covered by 
VK_KHR_performance_query (or equivalent GL ext)?

Best regards,

Rob Clark Aug. 27, 2024, 9:07 p.m. UTC | #13

On Tue, Aug 27, 2024 at 1:25 PM Antonino Maniscalco
<[e-mail]> wrote:
>
> On 8/27/24 9:48 PM, Akhil P Oommen wrote:
> > On Fri, Aug 23, 2024 at 10:23:48AM +0100, Connor Abbott wrote:
> >> On Fri, Aug 23, 2024 at 10:21 AM Connor Abbott <[e-mail]> wrote:
> >>>
> >>> On Thu, Aug 22, 2024 at 9:06 PM Akhil P Oommen <[e-mail]> wrote:
> >>>>
> >>>> On Wed, Aug 21, 2024 at 05:02:56PM +0100, Connor Abbott wrote:
> >>>>> On Mon, Aug 19, 2024 at 9:09 PM Akhil P Oommen <[e-mail]> wrote:
> >>>>>>
> >>>>>> On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
> >>>>>>> This patch implements preemption feature for A6xx targets, this allows
> >>>>>>> the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
> >>>>>>> hardware as such supports multiple levels of preemption granularities,
> >>>>>>> ranging from coarse grained(ringbuffer level) to a more fine grained
> >>>>>>> such as draw-call level or a bin boundary level preemption. This patch
> >>>>>>> enables the basic preemption level, with more fine grained preemption
> >>>>>>> support to follow.
> >>>>>>>
> >>>>>>> Signed-off-by: Sharat Masetty <[e-mail]>
> >>>>>>> Signed-off-by: Antonino Maniscalco <[e-mail]>
> >>>>>>> ---
> >>>>>>
> >>>>>> No postamble packets which resets perfcounters? It is necessary. Also, I
> >>>>>> think we should disable preemption during profiling like we disable slumber.
> >>>>>>
> >>>>>> -Akhil.
> >>>>>
> >>>>> I don't see anything in kgsl which disables preemption during
> >>>>> profiling. It disables resetting perfcounters when doing system-wide
> >>>>> profiling, like freedreno, and in that case I assume preempting is
> >>>>> fine because the system profiler has a complete view of everything and
> >>>>> should "see" preemptions through the traces. For something like
> >>>>> VK_KHR_performance_query I suppose we'd want to disable preemption
> >>>>> because we disable saving/restoring perf counters, but that has to
> >>>>> happen in userspace because the kernel doesn't know what userspace
> >>>>> does.
> >>>>>
> >>>>
> >>>> KGSL does some sort of arbitration of perfcounter configurations and
> >>>> adds the select/enablement reg configuration as part of dynamic
> >>>> power up register list which we are not doing here. Is this something
> >>>> you are taking care of from userspace via preamble?
> >>>>
> >>>> -Akhil
> >>>
> >>> I don't think we have to take care of that in userspace, because Mesa
> >>> will always configure the counter registers before reading them in the
> >>> same submission, and if it gets preempted in the meantime then we're
> >>> toast anyways (due to not saving/restoring perf counters). kgsl sets
> >>> them from userspace, which is why it has to do something to set them
> >>
> >> Sorry, should be "kgsl sets them from the kernel".
> >>
> >>> after IFPC slumber or a context switch when the HW state is gone.
> >>> Also, because the upstream approach doesn't play nicely with system
> >>> profilers like perfetto, VK_KHR_performance_query is hidden by default
> >>> behind a debug flag in turnip. So there's already an element of "this
> >>> is unsupported, you have to know what you're doing to use it."
> >
> > But when you have composition on GPU enabled, there will be very frequent
> > preemption. And I don't know how usable profiling tools will be in that
> > case unless you disable preemption with a Mesa debug flag. But for that
> > to work, all existing submitqueues should be destroyed and recreated.
> >
> > So I was thinking that we can use the sysprof propertry to force L0
> > preemption from kernel.
> >
> > -Akhil.
> >
>
> Right but when using a system profiler I imagined the expectation would
> be to be able to understand how applications and compositor interact. An
> use case could be measuring latency and understanding what contributes
> to it. That is actually the main reason I added traces for preemption.
> Disabling preemption would make it less useful for this type of
> analysis. Did you have an use case in mind for a system profiler that
> would benefit from disabling preemption and that is not covered by
> VK_KHR_performance_query (or equivalent GL ext)?

I would think that we want to generate an event, with GPU timestamp
(ie. RB_DONE) and which ring we are switching to, so that perfetto/etc
could display multiple GPU timelines and where the switch from one to
the other happens.

I'm a bit curious how this is handled on android, with AGI/etc.. I
don't see any support in perfetto for this.

BR,
-R

> Best regards,
> --
> Antonino Maniscalco <[e-mail]>
>

Antonino Maniscalco Aug. 27, 2024, 10:56 p.m. UTC | #14

On 8/27/24 11:07 PM, Rob Clark wrote:
> On Tue, Aug 27, 2024 at 1:25 PM Antonino Maniscalco
> <[e-mail]> wrote:
>>
>> On 8/27/24 9:48 PM, Akhil P Oommen wrote:
>>> On Fri, Aug 23, 2024 at 10:23:48AM +0100, Connor Abbott wrote:
>>>> On Fri, Aug 23, 2024 at 10:21 AM Connor Abbott <[e-mail]> wrote:
>>>>>
>>>>> On Thu, Aug 22, 2024 at 9:06 PM Akhil P Oommen <[e-mail]> wrote:
>>>>>>
>>>>>> On Wed, Aug 21, 2024 at 05:02:56PM +0100, Connor Abbott wrote:
>>>>>>> On Mon, Aug 19, 2024 at 9:09 PM Akhil P Oommen <[e-mail]> wrote:
>>>>>>>>
>>>>>>>> On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
>>>>>>>>> This patch implements preemption feature for A6xx targets, this allows
>>>>>>>>> the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
>>>>>>>>> hardware as such supports multiple levels of preemption granularities,
>>>>>>>>> ranging from coarse grained(ringbuffer level) to a more fine grained
>>>>>>>>> such as draw-call level or a bin boundary level preemption. This patch
>>>>>>>>> enables the basic preemption level, with more fine grained preemption
>>>>>>>>> support to follow.
>>>>>>>>>
>>>>>>>>> Signed-off-by: Sharat Masetty <[e-mail]>
>>>>>>>>> Signed-off-by: Antonino Maniscalco <[e-mail]>
>>>>>>>>> ---
>>>>>>>>
>>>>>>>> No postamble packets which resets perfcounters? It is necessary. Also, I
>>>>>>>> think we should disable preemption during profiling like we disable slumber.
>>>>>>>>
>>>>>>>> -Akhil.
>>>>>>>
>>>>>>> I don't see anything in kgsl which disables preemption during
>>>>>>> profiling. It disables resetting perfcounters when doing system-wide
>>>>>>> profiling, like freedreno, and in that case I assume preempting is
>>>>>>> fine because the system profiler has a complete view of everything and
>>>>>>> should "see" preemptions through the traces. For something like
>>>>>>> VK_KHR_performance_query I suppose we'd want to disable preemption
>>>>>>> because we disable saving/restoring perf counters, but that has to
>>>>>>> happen in userspace because the kernel doesn't know what userspace
>>>>>>> does.
>>>>>>>
>>>>>>
>>>>>> KGSL does some sort of arbitration of perfcounter configurations and
>>>>>> adds the select/enablement reg configuration as part of dynamic
>>>>>> power up register list which we are not doing here. Is this something
>>>>>> you are taking care of from userspace via preamble?
>>>>>>
>>>>>> -Akhil
>>>>>
>>>>> I don't think we have to take care of that in userspace, because Mesa
>>>>> will always configure the counter registers before reading them in the
>>>>> same submission, and if it gets preempted in the meantime then we're
>>>>> toast anyways (due to not saving/restoring perf counters). kgsl sets
>>>>> them from userspace, which is why it has to do something to set them
>>>>
>>>> Sorry, should be "kgsl sets them from the kernel".
>>>>
>>>>> after IFPC slumber or a context switch when the HW state is gone.
>>>>> Also, because the upstream approach doesn't play nicely with system
>>>>> profilers like perfetto, VK_KHR_performance_query is hidden by default
>>>>> behind a debug flag in turnip. So there's already an element of "this
>>>>> is unsupported, you have to know what you're doing to use it."
>>>
>>> But when you have composition on GPU enabled, there will be very frequent
>>> preemption. And I don't know how usable profiling tools will be in that
>>> case unless you disable preemption with a Mesa debug flag. But for that
>>> to work, all existing submitqueues should be destroyed and recreated.
>>>
>>> So I was thinking that we can use the sysprof propertry to force L0
>>> preemption from kernel.
>>>
>>> -Akhil.
>>>
>>
>> Right but when using a system profiler I imagined the expectation would
>> be to be able to understand how applications and compositor interact. An
>> use case could be measuring latency and understanding what contributes
>> to it. That is actually the main reason I added traces for preemption.
>> Disabling preemption would make it less useful for this type of
>> analysis. Did you have an use case in mind for a system profiler that
>> would benefit from disabling preemption and that is not covered by
>> VK_KHR_performance_query (or equivalent GL ext)?
> 
> I would think that we want to generate an event, with GPU timestamp
> (ie. RB_DONE) and which ring we are switching to, so that perfetto/etc
> could display multiple GPU timelines and where the switch from one to
> the other happens.
> 
> I'm a bit curious how this is handled on android, with AGI/etc.. I
> don't see any support in perfetto for this.
> 
> BR,
> -R
> 
>> Best regards,
>> --
>> Antonino Maniscalco <[e-mail]>
>>

Looking at KGSL they seem to use ftrace and I don't see it doing 
anything to get a timestamp from some GPU timer, really not sure how 
that would be put in a gpu timeline.

Best regards,

Rob Clark Aug. 28, 2024, 1:42 p.m. UTC | #15

On Tue, Aug 27, 2024 at 3:56 PM Antonino Maniscalco
<[e-mail]> wrote:
>
> On 8/27/24 11:07 PM, Rob Clark wrote:
> > On Tue, Aug 27, 2024 at 1:25 PM Antonino Maniscalco
> > <[e-mail]> wrote:
> >>
> >> On 8/27/24 9:48 PM, Akhil P Oommen wrote:
> >>> On Fri, Aug 23, 2024 at 10:23:48AM +0100, Connor Abbott wrote:
> >>>> On Fri, Aug 23, 2024 at 10:21 AM Connor Abbott <[e-mail]> wrote:
> >>>>>
> >>>>> On Thu, Aug 22, 2024 at 9:06 PM Akhil P Oommen <[e-mail]> wrote:
> >>>>>>
> >>>>>> On Wed, Aug 21, 2024 at 05:02:56PM +0100, Connor Abbott wrote:
> >>>>>>> On Mon, Aug 19, 2024 at 9:09 PM Akhil P Oommen <[e-mail]> wrote:
> >>>>>>>>
> >>>>>>>> On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
> >>>>>>>>> This patch implements preemption feature for A6xx targets, this allows
> >>>>>>>>> the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
> >>>>>>>>> hardware as such supports multiple levels of preemption granularities,
> >>>>>>>>> ranging from coarse grained(ringbuffer level) to a more fine grained
> >>>>>>>>> such as draw-call level or a bin boundary level preemption. This patch
> >>>>>>>>> enables the basic preemption level, with more fine grained preemption
> >>>>>>>>> support to follow.
> >>>>>>>>>
> >>>>>>>>> Signed-off-by: Sharat Masetty <[e-mail]>
> >>>>>>>>> Signed-off-by: Antonino Maniscalco <[e-mail]>
> >>>>>>>>> ---
> >>>>>>>>
> >>>>>>>> No postamble packets which resets perfcounters? It is necessary. Also, I
> >>>>>>>> think we should disable preemption during profiling like we disable slumber.
> >>>>>>>>
> >>>>>>>> -Akhil.
> >>>>>>>
> >>>>>>> I don't see anything in kgsl which disables preemption during
> >>>>>>> profiling. It disables resetting perfcounters when doing system-wide
> >>>>>>> profiling, like freedreno, and in that case I assume preempting is
> >>>>>>> fine because the system profiler has a complete view of everything and
> >>>>>>> should "see" preemptions through the traces. For something like
> >>>>>>> VK_KHR_performance_query I suppose we'd want to disable preemption
> >>>>>>> because we disable saving/restoring perf counters, but that has to
> >>>>>>> happen in userspace because the kernel doesn't know what userspace
> >>>>>>> does.
> >>>>>>>
> >>>>>>
> >>>>>> KGSL does some sort of arbitration of perfcounter configurations and
> >>>>>> adds the select/enablement reg configuration as part of dynamic
> >>>>>> power up register list which we are not doing here. Is this something
> >>>>>> you are taking care of from userspace via preamble?
> >>>>>>
> >>>>>> -Akhil
> >>>>>
> >>>>> I don't think we have to take care of that in userspace, because Mesa
> >>>>> will always configure the counter registers before reading them in the
> >>>>> same submission, and if it gets preempted in the meantime then we're
> >>>>> toast anyways (due to not saving/restoring perf counters). kgsl sets
> >>>>> them from userspace, which is why it has to do something to set them
> >>>>
> >>>> Sorry, should be "kgsl sets them from the kernel".
> >>>>
> >>>>> after IFPC slumber or a context switch when the HW state is gone.
> >>>>> Also, because the upstream approach doesn't play nicely with system
> >>>>> profilers like perfetto, VK_KHR_performance_query is hidden by default
> >>>>> behind a debug flag in turnip. So there's already an element of "this
> >>>>> is unsupported, you have to know what you're doing to use it."
> >>>
> >>> But when you have composition on GPU enabled, there will be very frequent
> >>> preemption. And I don't know how usable profiling tools will be in that
> >>> case unless you disable preemption with a Mesa debug flag. But for that
> >>> to work, all existing submitqueues should be destroyed and recreated.
> >>>
> >>> So I was thinking that we can use the sysprof propertry to force L0
> >>> preemption from kernel.
> >>>
> >>> -Akhil.
> >>>
> >>
> >> Right but when using a system profiler I imagined the expectation would
> >> be to be able to understand how applications and compositor interact. An
> >> use case could be measuring latency and understanding what contributes
> >> to it. That is actually the main reason I added traces for preemption.
> >> Disabling preemption would make it less useful for this type of
> >> analysis. Did you have an use case in mind for a system profiler that
> >> would benefit from disabling preemption and that is not covered by
> >> VK_KHR_performance_query (or equivalent GL ext)?
> >
> > I would think that we want to generate an event, with GPU timestamp
> > (ie. RB_DONE) and which ring we are switching to, so that perfetto/etc
> > could display multiple GPU timelines and where the switch from one to
> > the other happens.
> >
> > I'm a bit curious how this is handled on android, with AGI/etc.. I
> > don't see any support in perfetto for this.
> >
> > BR,
> > -R
> >
> >> Best regards,
> >> --
> >> Antonino Maniscalco <[e-mail]>
> >>
>
> Looking at KGSL they seem to use ftrace and I don't see it doing
> anything to get a timestamp from some GPU timer, really not sure how
> that would be put in a gpu timeline.

I suspect it would require some work on perfetto trace-processor.  It
can ingest ftrace events (but those would end up being something
driver specific).  Maybe with u_trace and some tracepoints in the
'ambles something could be done that would be more driver agnostic
(but idk if that would work for gpu's where preemption happens more
autonomously in the fw)

BR,
-R

> Best regards,
> --
> Antonino Maniscalco <[e-mail]>
>

Rob Clark Aug. 28, 2024, 1:46 p.m. UTC | #16

On Wed, Aug 28, 2024 at 6:42 AM Rob Clark <[e-mail]> wrote:
>
> On Tue, Aug 27, 2024 at 3:56 PM Antonino Maniscalco
> <[e-mail]> wrote:
> >
> > On 8/27/24 11:07 PM, Rob Clark wrote:
> > > On Tue, Aug 27, 2024 at 1:25 PM Antonino Maniscalco
> > > <[e-mail]> wrote:
> > >>
> > >> On 8/27/24 9:48 PM, Akhil P Oommen wrote:
> > >>> On Fri, Aug 23, 2024 at 10:23:48AM +0100, Connor Abbott wrote:
> > >>>> On Fri, Aug 23, 2024 at 10:21 AM Connor Abbott <[e-mail]> wrote:
> > >>>>>
> > >>>>> On Thu, Aug 22, 2024 at 9:06 PM Akhil P Oommen <[e-mail]> wrote:
> > >>>>>>
> > >>>>>> On Wed, Aug 21, 2024 at 05:02:56PM +0100, Connor Abbott wrote:
> > >>>>>>> On Mon, Aug 19, 2024 at 9:09 PM Akhil P Oommen <[e-mail]> wrote:
> > >>>>>>>>
> > >>>>>>>> On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
> > >>>>>>>>> This patch implements preemption feature for A6xx targets, this allows
> > >>>>>>>>> the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
> > >>>>>>>>> hardware as such supports multiple levels of preemption granularities,
> > >>>>>>>>> ranging from coarse grained(ringbuffer level) to a more fine grained
> > >>>>>>>>> such as draw-call level or a bin boundary level preemption. This patch
> > >>>>>>>>> enables the basic preemption level, with more fine grained preemption
> > >>>>>>>>> support to follow.
> > >>>>>>>>>
> > >>>>>>>>> Signed-off-by: Sharat Masetty <[e-mail]>
> > >>>>>>>>> Signed-off-by: Antonino Maniscalco <[e-mail]>
> > >>>>>>>>> ---
> > >>>>>>>>
> > >>>>>>>> No postamble packets which resets perfcounters? It is necessary. Also, I
> > >>>>>>>> think we should disable preemption during profiling like we disable slumber.
> > >>>>>>>>
> > >>>>>>>> -Akhil.
> > >>>>>>>
> > >>>>>>> I don't see anything in kgsl which disables preemption during
> > >>>>>>> profiling. It disables resetting perfcounters when doing system-wide
> > >>>>>>> profiling, like freedreno, and in that case I assume preempting is
> > >>>>>>> fine because the system profiler has a complete view of everything and
> > >>>>>>> should "see" preemptions through the traces. For something like
> > >>>>>>> VK_KHR_performance_query I suppose we'd want to disable preemption
> > >>>>>>> because we disable saving/restoring perf counters, but that has to
> > >>>>>>> happen in userspace because the kernel doesn't know what userspace
> > >>>>>>> does.
> > >>>>>>>
> > >>>>>>
> > >>>>>> KGSL does some sort of arbitration of perfcounter configurations and
> > >>>>>> adds the select/enablement reg configuration as part of dynamic
> > >>>>>> power up register list which we are not doing here. Is this something
> > >>>>>> you are taking care of from userspace via preamble?
> > >>>>>>
> > >>>>>> -Akhil
> > >>>>>
> > >>>>> I don't think we have to take care of that in userspace, because Mesa
> > >>>>> will always configure the counter registers before reading them in the
> > >>>>> same submission, and if it gets preempted in the meantime then we're
> > >>>>> toast anyways (due to not saving/restoring perf counters). kgsl sets
> > >>>>> them from userspace, which is why it has to do something to set them
> > >>>>
> > >>>> Sorry, should be "kgsl sets them from the kernel".
> > >>>>
> > >>>>> after IFPC slumber or a context switch when the HW state is gone.
> > >>>>> Also, because the upstream approach doesn't play nicely with system
> > >>>>> profilers like perfetto, VK_KHR_performance_query is hidden by default
> > >>>>> behind a debug flag in turnip. So there's already an element of "this
> > >>>>> is unsupported, you have to know what you're doing to use it."
> > >>>
> > >>> But when you have composition on GPU enabled, there will be very frequent
> > >>> preemption. And I don't know how usable profiling tools will be in that
> > >>> case unless you disable preemption with a Mesa debug flag. But for that
> > >>> to work, all existing submitqueues should be destroyed and recreated.
> > >>>
> > >>> So I was thinking that we can use the sysprof propertry to force L0
> > >>> preemption from kernel.
> > >>>
> > >>> -Akhil.
> > >>>
> > >>
> > >> Right but when using a system profiler I imagined the expectation would
> > >> be to be able to understand how applications and compositor interact. An
> > >> use case could be measuring latency and understanding what contributes
> > >> to it. That is actually the main reason I added traces for preemption.
> > >> Disabling preemption would make it less useful for this type of
> > >> analysis. Did you have an use case in mind for a system profiler that
> > >> would benefit from disabling preemption and that is not covered by
> > >> VK_KHR_performance_query (or equivalent GL ext)?
> > >
> > > I would think that we want to generate an event, with GPU timestamp
> > > (ie. RB_DONE) and which ring we are switching to, so that perfetto/etc
> > > could display multiple GPU timelines and where the switch from one to
> > > the other happens.
> > >
> > > I'm a bit curious how this is handled on android, with AGI/etc.. I
> > > don't see any support in perfetto for this.
> > >
> > > BR,
> > > -R
> > >
> > >> Best regards,
> > >> --
> > >> Antonino Maniscalco <[e-mail]>
> > >>
> >
> > Looking at KGSL they seem to use ftrace and I don't see it doing
> > anything to get a timestamp from some GPU timer, really not sure how
> > that would be put in a gpu timeline.
>
> I suspect it would require some work on perfetto trace-processor.  It
> can ingest ftrace events (but those would end up being something
> driver specific).  Maybe with u_trace and some tracepoints in the
> 'ambles something could be done that would be more driver agnostic
> (but idk if that would work for gpu's where preemption happens more
> autonomously in the fw)

btw how to handle tracing preemption probably shouldn't hold up
sending the next iteration of this series.  There isn't that much more
time to get this in v6.12, and I think better visualization of
preemption is going to take some work outside of the kernel.

BR,
-R

Akhil P Oommen Aug. 28, 2024, 7:23 p.m. UTC | #17

On Wed, Aug 28, 2024 at 06:46:37AM -0700, Rob Clark wrote:
> On Wed, Aug 28, 2024 at 6:42 AM Rob Clark <[e-mail]> wrote:
> >
> > On Tue, Aug 27, 2024 at 3:56 PM Antonino Maniscalco
> > <[e-mail]> wrote:
> > >
> > > On 8/27/24 11:07 PM, Rob Clark wrote:
> > > > On Tue, Aug 27, 2024 at 1:25 PM Antonino Maniscalco
> > > > <[e-mail]> wrote:
> > > >>
> > > >> On 8/27/24 9:48 PM, Akhil P Oommen wrote:
> > > >>> On Fri, Aug 23, 2024 at 10:23:48AM +0100, Connor Abbott wrote:
> > > >>>> On Fri, Aug 23, 2024 at 10:21 AM Connor Abbott <[e-mail]> wrote:
> > > >>>>>
> > > >>>>> On Thu, Aug 22, 2024 at 9:06 PM Akhil P Oommen <[e-mail]> wrote:
> > > >>>>>>
> > > >>>>>> On Wed, Aug 21, 2024 at 05:02:56PM +0100, Connor Abbott wrote:
> > > >>>>>>> On Mon, Aug 19, 2024 at 9:09 PM Akhil P Oommen <[e-mail]> wrote:
> > > >>>>>>>>
> > > >>>>>>>> On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
> > > >>>>>>>>> This patch implements preemption feature for A6xx targets, this allows
> > > >>>>>>>>> the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
> > > >>>>>>>>> hardware as such supports multiple levels of preemption granularities,
> > > >>>>>>>>> ranging from coarse grained(ringbuffer level) to a more fine grained
> > > >>>>>>>>> such as draw-call level or a bin boundary level preemption. This patch
> > > >>>>>>>>> enables the basic preemption level, with more fine grained preemption
> > > >>>>>>>>> support to follow.
> > > >>>>>>>>>
> > > >>>>>>>>> Signed-off-by: Sharat Masetty <[e-mail]>
> > > >>>>>>>>> Signed-off-by: Antonino Maniscalco <[e-mail]>
> > > >>>>>>>>> ---
> > > >>>>>>>>
> > > >>>>>>>> No postamble packets which resets perfcounters? It is necessary. Also, I
> > > >>>>>>>> think we should disable preemption during profiling like we disable slumber.
> > > >>>>>>>>
> > > >>>>>>>> -Akhil.
> > > >>>>>>>
> > > >>>>>>> I don't see anything in kgsl which disables preemption during
> > > >>>>>>> profiling. It disables resetting perfcounters when doing system-wide
> > > >>>>>>> profiling, like freedreno, and in that case I assume preempting is
> > > >>>>>>> fine because the system profiler has a complete view of everything and
> > > >>>>>>> should "see" preemptions through the traces. For something like
> > > >>>>>>> VK_KHR_performance_query I suppose we'd want to disable preemption
> > > >>>>>>> because we disable saving/restoring perf counters, but that has to
> > > >>>>>>> happen in userspace because the kernel doesn't know what userspace
> > > >>>>>>> does.
> > > >>>>>>>
> > > >>>>>>
> > > >>>>>> KGSL does some sort of arbitration of perfcounter configurations and
> > > >>>>>> adds the select/enablement reg configuration as part of dynamic
> > > >>>>>> power up register list which we are not doing here. Is this something
> > > >>>>>> you are taking care of from userspace via preamble?
> > > >>>>>>
> > > >>>>>> -Akhil
> > > >>>>>
> > > >>>>> I don't think we have to take care of that in userspace, because Mesa
> > > >>>>> will always configure the counter registers before reading them in the
> > > >>>>> same submission, and if it gets preempted in the meantime then we're
> > > >>>>> toast anyways (due to not saving/restoring perf counters). kgsl sets
> > > >>>>> them from userspace, which is why it has to do something to set them
> > > >>>>
> > > >>>> Sorry, should be "kgsl sets them from the kernel".
> > > >>>>
> > > >>>>> after IFPC slumber or a context switch when the HW state is gone.
> > > >>>>> Also, because the upstream approach doesn't play nicely with system
> > > >>>>> profilers like perfetto, VK_KHR_performance_query is hidden by default
> > > >>>>> behind a debug flag in turnip. So there's already an element of "this
> > > >>>>> is unsupported, you have to know what you're doing to use it."
> > > >>>
> > > >>> But when you have composition on GPU enabled, there will be very frequent
> > > >>> preemption. And I don't know how usable profiling tools will be in that
> > > >>> case unless you disable preemption with a Mesa debug flag. But for that
> > > >>> to work, all existing submitqueues should be destroyed and recreated.
> > > >>>
> > > >>> So I was thinking that we can use the sysprof propertry to force L0
> > > >>> preemption from kernel.
> > > >>>
> > > >>> -Akhil.
> > > >>>
> > > >>
> > > >> Right but when using a system profiler I imagined the expectation would
> > > >> be to be able to understand how applications and compositor interact. An
> > > >> use case could be measuring latency and understanding what contributes
> > > >> to it. That is actually the main reason I added traces for preemption.
> > > >> Disabling preemption would make it less useful for this type of
> > > >> analysis. Did you have an use case in mind for a system profiler that
> > > >> would benefit from disabling preemption and that is not covered by
> > > >> VK_KHR_performance_query (or equivalent GL ext)?

Please consider this as a friendly suggestion based on Conner's clarification.
Not a blocker. TBH, I don't have clairty on the profiling story in Mesa!

> > > >
> > > > I would think that we want to generate an event, with GPU timestamp
> > > > (ie. RB_DONE) and which ring we are switching to, so that perfetto/etc
> > > > could display multiple GPU timelines and where the switch from one to
> > > > the other happens.
> > > >
> > > > I'm a bit curious how this is handled on android, with AGI/etc.. I
> > > > don't see any support in perfetto for this.
> > > >
> > > > BR,
> > > > -R
> > > >
> > > >> Best regards,
> > > >> --
> > > >> Antonino Maniscalco <[e-mail]>
> > > >>
> > >
> > > Looking at KGSL they seem to use ftrace and I don't see it doing
> > > anything to get a timestamp from some GPU timer, really not sure how
> > > that would be put in a gpu timeline.

Yeah, we usually rely on ftraces which is good enough to measure preemption
latency.

-Akhil.

> >
> > I suspect it would require some work on perfetto trace-processor.  It
> > can ingest ftrace events (but those would end up being something
> > driver specific).  Maybe with u_trace and some tracepoints in the
> > 'ambles something could be done that would be more driver agnostic
> > (but idk if that would work for gpu's where preemption happens more
> > autonomously in the fw)
> 
> btw how to handle tracing preemption probably shouldn't hold up
> sending the next iteration of this series.  There isn't that much more
> time to get this in v6.12, and I think better visualization of
> preemption is going to take some work outside of the kernel.
> 
> BR,
> -R

Antonino Maniscalco Aug. 28, 2024, 7:46 p.m. UTC | #18

On 8/28/24 9:23 PM, Akhil P Oommen wrote:
> On Wed, Aug 28, 2024 at 06:46:37AM -0700, Rob Clark wrote:
>> On Wed, Aug 28, 2024 at 6:42 AM Rob Clark <[e-mail]> wrote:
>>>
>>> On Tue, Aug 27, 2024 at 3:56 PM Antonino Maniscalco
>>> <[e-mail]> wrote:
>>>>
>>>> On 8/27/24 11:07 PM, Rob Clark wrote:
>>>>> On Tue, Aug 27, 2024 at 1:25 PM Antonino Maniscalco
>>>>> <[e-mail]> wrote:
>>>>>>
>>>>>> On 8/27/24 9:48 PM, Akhil P Oommen wrote:
>>>>>>> On Fri, Aug 23, 2024 at 10:23:48AM +0100, Connor Abbott wrote:
>>>>>>>> On Fri, Aug 23, 2024 at 10:21 AM Connor Abbott <[e-mail]> wrote:
>>>>>>>>>
>>>>>>>>> On Thu, Aug 22, 2024 at 9:06 PM Akhil P Oommen <[e-mail]> wrote:
>>>>>>>>>>
>>>>>>>>>> On Wed, Aug 21, 2024 at 05:02:56PM +0100, Connor Abbott wrote:
>>>>>>>>>>> On Mon, Aug 19, 2024 at 9:09 PM Akhil P Oommen <[e-mail]> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>> On Thu, Aug 15, 2024 at 08:26:14PM +0200, Antonino Maniscalco wrote:
>>>>>>>>>>>>> This patch implements preemption feature for A6xx targets, this allows
>>>>>>>>>>>>> the GPU to switch to a higher priority ringbuffer if one is ready. A6XX
>>>>>>>>>>>>> hardware as such supports multiple levels of preemption granularities,
>>>>>>>>>>>>> ranging from coarse grained(ringbuffer level) to a more fine grained
>>>>>>>>>>>>> such as draw-call level or a bin boundary level preemption. This patch
>>>>>>>>>>>>> enables the basic preemption level, with more fine grained preemption
>>>>>>>>>>>>> support to follow.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Signed-off-by: Sharat Masetty <[e-mail]>
>>>>>>>>>>>>> Signed-off-by: Antonino Maniscalco <[e-mail]>
>>>>>>>>>>>>> ---
>>>>>>>>>>>>
>>>>>>>>>>>> No postamble packets which resets perfcounters? It is necessary. Also, I
>>>>>>>>>>>> think we should disable preemption during profiling like we disable slumber.
>>>>>>>>>>>>
>>>>>>>>>>>> -Akhil.
>>>>>>>>>>>
>>>>>>>>>>> I don't see anything in kgsl which disables preemption during
>>>>>>>>>>> profiling. It disables resetting perfcounters when doing system-wide
>>>>>>>>>>> profiling, like freedreno, and in that case I assume preempting is
>>>>>>>>>>> fine because the system profiler has a complete view of everything and
>>>>>>>>>>> should "see" preemptions through the traces. For something like
>>>>>>>>>>> VK_KHR_performance_query I suppose we'd want to disable preemption
>>>>>>>>>>> because we disable saving/restoring perf counters, but that has to
>>>>>>>>>>> happen in userspace because the kernel doesn't know what userspace
>>>>>>>>>>> does.
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> KGSL does some sort of arbitration of perfcounter configurations and
>>>>>>>>>> adds the select/enablement reg configuration as part of dynamic
>>>>>>>>>> power up register list which we are not doing here. Is this something
>>>>>>>>>> you are taking care of from userspace via preamble?
>>>>>>>>>>
>>>>>>>>>> -Akhil
>>>>>>>>>
>>>>>>>>> I don't think we have to take care of that in userspace, because Mesa
>>>>>>>>> will always configure the counter registers before reading them in the
>>>>>>>>> same submission, and if it gets preempted in the meantime then we're
>>>>>>>>> toast anyways (due to not saving/restoring perf counters). kgsl sets
>>>>>>>>> them from userspace, which is why it has to do something to set them
>>>>>>>>
>>>>>>>> Sorry, should be "kgsl sets them from the kernel".
>>>>>>>>
>>>>>>>>> after IFPC slumber or a context switch when the HW state is gone.
>>>>>>>>> Also, because the upstream approach doesn't play nicely with system
>>>>>>>>> profilers like perfetto, VK_KHR_performance_query is hidden by default
>>>>>>>>> behind a debug flag in turnip. So there's already an element of "this
>>>>>>>>> is unsupported, you have to know what you're doing to use it."
>>>>>>>
>>>>>>> But when you have composition on GPU enabled, there will be very frequent
>>>>>>> preemption. And I don't know how usable profiling tools will be in that
>>>>>>> case unless you disable preemption with a Mesa debug flag. But for that
>>>>>>> to work, all existing submitqueues should be destroyed and recreated.
>>>>>>>
>>>>>>> So I was thinking that we can use the sysprof propertry to force L0
>>>>>>> preemption from kernel.
>>>>>>>
>>>>>>> -Akhil.
>>>>>>>
>>>>>>
>>>>>> Right but when using a system profiler I imagined the expectation would
>>>>>> be to be able to understand how applications and compositor interact. An
>>>>>> use case could be measuring latency and understanding what contributes
>>>>>> to it. That is actually the main reason I added traces for preemption.
>>>>>> Disabling preemption would make it less useful for this type of
>>>>>> analysis. Did you have an use case in mind for a system profiler that
>>>>>> would benefit from disabling preemption and that is not covered by
>>>>>> VK_KHR_performance_query (or equivalent GL ext)?
> 
> Please consider this as a friendly suggestion based on Conner's clarification.
> Not a blocker. TBH, I don't have clairty on the profiling story in Mesa!
> 

Thanks, your input was appreciated :) I just wanted to make sure we 
where on the same page. So considering this, I will be able to send v2 soon.

>>>>>
>>>>> I would think that we want to generate an event, with GPU timestamp
>>>>> (ie. RB_DONE) and which ring we are switching to, so that perfetto/etc
>>>>> could display multiple GPU timelines and where the switch from one to
>>>>> the other happens.
>>>>>
>>>>> I'm a bit curious how this is handled on android, with AGI/etc.. I
>>>>> don't see any support in perfetto for this.
>>>>>
>>>>> BR,
>>>>> -R
>>>>>
>>>>>> Best regards,
>>>>>> --
>>>>>> Antonino Maniscalco <[e-mail]>
>>>>>>
>>>>
>>>> Looking at KGSL they seem to use ftrace and I don't see it doing
>>>> anything to get a timestamp from some GPU timer, really not sure how
>>>> that would be put in a gpu timeline.
> 
> Yeah, we usually rely on ftraces which is good enough to measure preemption
> latency.
> 
> -Akhil.
> 

Thanks for confirming! The traces I added are pretty similar to KGSL's 
so it should be suitable for serving the same purpose.

>>>
>>> I suspect it would require some work on perfetto trace-processor.  It
>>> can ingest ftrace events (but those would end up being something
>>> driver specific).  Maybe with u_trace and some tracepoints in the
>>> 'ambles something could be done that would be more driver agnostic
>>> (but idk if that would work for gpu's where preemption happens more
>>> autonomously in the fw)
>>
>> btw how to handle tracing preemption probably shouldn't hold up
>> sending the next iteration of this series.  There isn't that much more
>> time to get this in v6.12, and I think better visualization of
>> preemption is going to take some work outside of the kernel.
>>
>> BR,
>> -R

Best regards,

Patch

diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile
index f5e2838c6a76..32e915109a59 100644
--- a/drivers/gpu/drm/msm/Makefile
+++ b/drivers/gpu/drm/msm/Makefile
@@ -23,6 +23,7 @@  adreno-y := \
 	adreno/a6xx_gpu.o \
 	adreno/a6xx_gmu.o \
 	adreno/a6xx_hfi.o \
+	adreno/a6xx_preempt.o \
 
 adreno-$(CONFIG_DEBUG_FS) += adreno/a5xx_debugfs.o \
 
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 32a4faa93d7f..1a90db5759b8 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -16,6 +16,83 @@ 
 
 #define GPU_PAS_ID 13
 
+/* IFPC & Preemption static powerup restore list */
+static const uint32_t a7xx_pwrup_reglist[] = {
+	REG_A6XX_UCHE_TRAP_BASE,
+	REG_A6XX_UCHE_TRAP_BASE + 1,
+	REG_A6XX_UCHE_WRITE_THRU_BASE,
+	REG_A6XX_UCHE_WRITE_THRU_BASE + 1,
+	REG_A6XX_UCHE_GMEM_RANGE_MIN,
+	REG_A6XX_UCHE_GMEM_RANGE_MIN + 1,
+	REG_A6XX_UCHE_GMEM_RANGE_MAX,
+	REG_A6XX_UCHE_GMEM_RANGE_MAX + 1,
+	REG_A6XX_UCHE_CACHE_WAYS,
+	REG_A6XX_UCHE_MODE_CNTL,
+	REG_A6XX_RB_NC_MODE_CNTL,
+	REG_A6XX_RB_CMP_DBG_ECO_CNTL,
+	REG_A7XX_GRAS_NC_MODE_CNTL,
+	REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE,
+	REG_A6XX_UCHE_GBIF_GX_CONFIG,
+	REG_A6XX_UCHE_CLIENT_PF,
+};
+
+static const uint32_t a7xx_ifpc_pwrup_reglist[] = {
+	REG_A6XX_TPL1_NC_MODE_CNTL,
+	REG_A6XX_SP_NC_MODE_CNTL,
+	REG_A6XX_CP_DBG_ECO_CNTL,
+	REG_A6XX_CP_PROTECT_CNTL,
+	REG_A6XX_CP_PROTECT(0),
+	REG_A6XX_CP_PROTECT(1),
+	REG_A6XX_CP_PROTECT(2),
+	REG_A6XX_CP_PROTECT(3),
+	REG_A6XX_CP_PROTECT(4),
+	REG_A6XX_CP_PROTECT(5),
+	REG_A6XX_CP_PROTECT(6),
+	REG_A6XX_CP_PROTECT(7),
+	REG_A6XX_CP_PROTECT(8),
+	REG_A6XX_CP_PROTECT(9),
+	REG_A6XX_CP_PROTECT(10),
+	REG_A6XX_CP_PROTECT(11),
+	REG_A6XX_CP_PROTECT(12),
+	REG_A6XX_CP_PROTECT(13),
+	REG_A6XX_CP_PROTECT(14),
+	REG_A6XX_CP_PROTECT(15),
+	REG_A6XX_CP_PROTECT(16),
+	REG_A6XX_CP_PROTECT(17),
+	REG_A6XX_CP_PROTECT(18),
+	REG_A6XX_CP_PROTECT(19),
+	REG_A6XX_CP_PROTECT(20),
+	REG_A6XX_CP_PROTECT(21),
+	REG_A6XX_CP_PROTECT(22),
+	REG_A6XX_CP_PROTECT(23),
+	REG_A6XX_CP_PROTECT(24),
+	REG_A6XX_CP_PROTECT(25),
+	REG_A6XX_CP_PROTECT(26),
+	REG_A6XX_CP_PROTECT(27),
+	REG_A6XX_CP_PROTECT(28),
+	REG_A6XX_CP_PROTECT(29),
+	REG_A6XX_CP_PROTECT(30),
+	REG_A6XX_CP_PROTECT(31),
+	REG_A6XX_CP_PROTECT(32),
+	REG_A6XX_CP_PROTECT(33),
+	REG_A6XX_CP_PROTECT(34),
+	REG_A6XX_CP_PROTECT(35),
+	REG_A6XX_CP_PROTECT(36),
+	REG_A6XX_CP_PROTECT(37),
+	REG_A6XX_CP_PROTECT(38),
+	REG_A6XX_CP_PROTECT(39),
+	REG_A6XX_CP_PROTECT(40),
+	REG_A6XX_CP_PROTECT(41),
+	REG_A6XX_CP_PROTECT(42),
+	REG_A6XX_CP_PROTECT(43),
+	REG_A6XX_CP_PROTECT(44),
+	REG_A6XX_CP_PROTECT(45),
+	REG_A6XX_CP_PROTECT(46),
+	REG_A6XX_CP_PROTECT(47),
+	REG_A6XX_CP_AHB_CNTL,
+};
+
+
 static inline bool _a6xx_check_idle(struct msm_gpu *gpu)
 {
 	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
@@ -68,6 +145,8 @@  static void update_shadow_rptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
 
 static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
 {
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
 	uint32_t wptr;
 	unsigned long flags;
 
@@ -81,12 +160,26 @@  static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
 	/* Make sure to wrap wptr if we need to */
 	wptr = get_wptr(ring);
 
-	spin_unlock_irqrestore(&ring->preempt_lock, flags);
-
 	/* Make sure everything is posted before making a decision */
 	mb();
 
-	gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
+	/* Update HW if this is the current ring and we are not in preempt*/
+	if (!a6xx_in_preempt(a6xx_gpu)) {
+		/*
+		 * Order the reads of the preempt state and cur_ring. This
+		 * matches the barrier after writing cur_ring.
+		 */
+		rmb();
+
+		if (a6xx_gpu->cur_ring == ring)
+			gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
+		else
+			ring->skip_inline_wptr = true;
+	} else {
+		ring->skip_inline_wptr = true;
+	}
+
+	spin_unlock_irqrestore(&ring->preempt_lock, flags);
 }
 
 static void get_stats_counter(struct msm_ringbuffer *ring, u32 counter,
@@ -138,12 +231,14 @@  static void a6xx_set_pagetable(struct a6xx_gpu *a6xx_gpu,
 
 	/*
 	 * Write the new TTBR0 to the memstore. This is good for debugging.
+	 * Needed for preemption
 	 */
-	OUT_PKT7(ring, CP_MEM_WRITE, 4);
+	OUT_PKT7(ring, CP_MEM_WRITE, 5);
 	OUT_RING(ring, CP_MEM_WRITE_0_ADDR_LO(lower_32_bits(memptr)));
 	OUT_RING(ring, CP_MEM_WRITE_1_ADDR_HI(upper_32_bits(memptr)));
 	OUT_RING(ring, lower_32_bits(ttbr));
-	OUT_RING(ring, (asid << 16) | upper_32_bits(ttbr));
+	OUT_RING(ring, upper_32_bits(ttbr));
+	OUT_RING(ring, ctx->seqno);
 
 	/*
 	 * Sync both threads after switching pagetables and enable BR only
@@ -268,12 +363,55 @@  static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
 	a6xx_flush(gpu, ring);
 }
 
+static void a6xx_emit_set_pseudo_reg(struct msm_ringbuffer *ring,
+		struct a6xx_gpu *a6xx_gpu, struct msm_gpu_submitqueue *queue)
+{
+	u64 preempt_offset_priv_secure;
+
+	OUT_PKT7(ring, CP_SET_PSEUDO_REG, 15);
+
+	OUT_RING(ring, SMMU_INFO);
+	/* don't save SMMU, we write the record from the kernel instead */
+	OUT_RING(ring, 0);
+	OUT_RING(ring, 0);
+
+	/* privileged and non secure buffer save */
+	OUT_RING(ring, NON_SECURE_SAVE_ADDR);
+	OUT_RING(ring, lower_32_bits(
+		a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE));
+	OUT_RING(ring, upper_32_bits(
+		a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE));
+	OUT_RING(ring, SECURE_SAVE_ADDR);
+	preempt_offset_priv_secure =
+		PREEMPT_OFFSET_PRIV_SECURE(a6xx_gpu->base.info->preempt_record_size);
+	OUT_RING(ring, lower_32_bits(
+		a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure));
+	OUT_RING(ring, upper_32_bits(
+		a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure));
+
+	/* user context buffer save */
+	OUT_RING(ring, NON_PRIV_SAVE_ADDR);
+	if (queue) {
+		OUT_RING(ring, lower_32_bits(queue->bo_iova));
+		OUT_RING(ring, upper_32_bits(queue->bo_iova));
+	} else {
+		OUT_RING(ring, 0);
+		OUT_RING(ring, 0);
+	}
+
+	OUT_RING(ring, COUNTER);
+	/* seems OK to set to 0 to disable it */
+	OUT_RING(ring, 0);
+	OUT_RING(ring, 0);
+}
+
 static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
 {
 	unsigned int index = submit->seqno % MSM_GPU_SUBMIT_STATS_COUNT;
 	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
 	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
 	struct msm_ringbuffer *ring = submit->ring;
+	uint64_t scratch_dest = SCRATCH_USER_CTX_IOVA(ring->id, a6xx_gpu);
 	unsigned int i, ibs = 0;
 
 	/*
@@ -283,6 +421,25 @@  static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
 	OUT_PKT7(ring, CP_THREAD_CONTROL, 1);
 	OUT_RING(ring, CP_THREAD_CONTROL_0_SYNC_THREADS | CP_SET_THREAD_BR);
 
+	/*
+	 * If preemption is enabled, then set the pseudo register for the save
+	 * sequence
+	 */
+	if (gpu->nr_rings > 1) {
+		a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, submit->queue);
+
+		/*
+		 * Ask CP to save the user context buffer's iova address to a
+		 * scratch memory region, this is needed if the CP preempts
+		 * this ring in between this submit's IB list.
+		 */
+		OUT_PKT7(ring, CP_MEM_WRITE, 4);
+		OUT_RING(ring, lower_32_bits(scratch_dest));
+		OUT_RING(ring, upper_32_bits(scratch_dest));
+		OUT_RING(ring, lower_32_bits(submit->queue->bo_iova));
+		OUT_RING(ring, upper_32_bits(submit->queue->bo_iova));
+	}
+
 	a6xx_set_pagetable(a6xx_gpu, ring, submit->queue->ctx);
 
 	get_stats_counter(ring, REG_A7XX_RBBM_PERFCTR_CP(0),
@@ -376,6 +533,8 @@  static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
 	OUT_RING(ring, upper_32_bits(rbmemptr(ring, bv_fence)));
 	OUT_RING(ring, submit->seqno);
 
+	a6xx_gpu->last_seqno[ring->id] = submit->seqno;
+
 	/* write the ringbuffer timestamp */
 	OUT_PKT7(ring, CP_EVENT_WRITE, 4);
 	OUT_RING(ring, CACHE_CLEAN | CP_EVENT_WRITE_0_IRQ | BIT(27));
@@ -389,10 +548,42 @@  static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
 	OUT_PKT7(ring, CP_SET_MARKER, 1);
 	OUT_RING(ring, 0x100); /* IFPC enable */
 
+	/* If preemption is enabled */
+	if (gpu->nr_rings > 1) {
+		/*
+		 * Reset the scratch region as we are done with the
+		 * IB list of this submission
+		 */
+		OUT_PKT7(ring, CP_MEM_WRITE, 4);
+		OUT_RING(ring, lower_32_bits(scratch_dest));
+		OUT_RING(ring, upper_32_bits(scratch_dest));
+		OUT_RING(ring, 0x00);
+		OUT_RING(ring, 0x00);
+
+		/* Yield the floor on command completion */
+		OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
+
+		/*
+		 * If dword[2:1] are non zero, they specify an address for
+		 * the CP to write the value of dword[3] to on preemption
+		 * complete. Write 0 to skip the write
+		 */
+		OUT_RING(ring, 0x00);
+		OUT_RING(ring, 0x00);
+		/* Data value - not used if the address above is 0 */
+		OUT_RING(ring, 0x01);
+		/* generate interrupt on preemption completion */
+		OUT_RING(ring, 0x00);
+	}
+
+
 	trace_msm_gpu_submit_flush(submit,
 		gpu_read64(gpu, REG_A6XX_CP_ALWAYS_ON_COUNTER));
 
 	a6xx_flush(gpu, ring);
+
+	/* Check to see if we need to start preemption */
+	a6xx_preempt_trigger(gpu);
 }
 
 static void a6xx_set_hwcg(struct msm_gpu *gpu, bool state)
@@ -588,6 +779,89 @@  static void a6xx_set_ubwc_config(struct msm_gpu *gpu)
 		  adreno_gpu->ubwc_config.min_acc_len << 23 | hbb_lo << 21);
 }
 
+static void a7xx_patch_pwrup_reglist(struct msm_gpu *gpu)
+{
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+	struct adreno_reglist_list reglist[2];
+	void *ptr = a6xx_gpu->pwrup_reglist_ptr;
+	struct cpu_gpu_lock *lock = ptr;
+	u32 *dest = (u32 *)&lock->regs[0];
+	int i, j;
+
+	lock->gpu_req = lock->cpu_req = lock->turn = 0;
+	lock->ifpc_list_len = ARRAY_SIZE(a7xx_ifpc_pwrup_reglist);
+	lock->preemption_list_len = ARRAY_SIZE(a7xx_pwrup_reglist);
+
+	/* Static IFPC-only registers */
+	reglist[0].regs = a7xx_ifpc_pwrup_reglist;
+	reglist[0].count = ARRAY_SIZE(a7xx_ifpc_pwrup_reglist);
+	lock->ifpc_list_len = reglist[0].count;
+
+	/* Static IFPC + preemption registers */
+	reglist[1].regs = a7xx_pwrup_reglist;
+	reglist[1].count = ARRAY_SIZE(a7xx_pwrup_reglist);
+	lock->preemption_list_len = reglist[1].count;
+
+	/*
+	 * For each entry in each of the lists, write the offset and the current
+	 * register value into the GPU buffer
+	 */
+	for (i = 0; i < 2; i++) {
+		const u32 *r = reglist[i].regs;
+
+		for (j = 0; j < reglist[i].count; j++) {
+			*dest++ = r[j];
+			*dest++ = gpu_read(gpu, r[j]);
+		}
+	}
+
+	/*
+	 * The overall register list is composed of
+	 * 1. Static IFPC-only registers
+	 * 2. Static IFPC + preemption registers
+	 * 3. Dynamic IFPC + preemption registers (ex: perfcounter selects)
+	 *
+	 * The first two lists are static. Size of these lists are stored as
+	 * number of pairs in ifpc_list_len and preemption_list_len
+	 * respectively. With concurrent binning, Some of the perfcounter
+	 * registers being virtualized, CP needs to know the pipe id to program
+	 * the aperture inorder to restore the same. Thus, third list is a
+	 * dynamic list with triplets as
+	 * (<aperture, shifted 12 bits> <address> <data>), and the length is
+	 * stored as number for triplets in dynamic_list_len.
+	 */
+	lock->dynamic_list_len = 0;
+}
+
+static int a7xx_preempt_start(struct msm_gpu *gpu)
+{
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+	struct msm_ringbuffer *ring = gpu->rb[0];
+
+	if (gpu->nr_rings <= 1)
+		return 0;
+
+	/* Turn CP protection off */
+	OUT_PKT7(ring, CP_SET_PROTECTED_MODE, 1);
+	OUT_RING(ring, 0);
+
+	a6xx_emit_set_pseudo_reg(ring, a6xx_gpu, NULL);
+
+	/* Yield the floor on command completion */
+	OUT_PKT7(ring, CP_CONTEXT_SWITCH_YIELD, 4);
+	OUT_RING(ring, 0x00);
+	OUT_RING(ring, 0x00);
+	OUT_RING(ring, 0x01);
+	/* Generate interrupt on preemption completion */
+	OUT_RING(ring, 0x00);
+
+	a6xx_flush(gpu, ring);
+
+	return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
+}
+
 static int a6xx_cp_init(struct msm_gpu *gpu)
 {
 	struct msm_ringbuffer *ring = gpu->rb[0];
@@ -619,6 +893,8 @@  static int a6xx_cp_init(struct msm_gpu *gpu)
 
 static int a7xx_cp_init(struct msm_gpu *gpu)
 {
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
 	struct msm_ringbuffer *ring = gpu->rb[0];
 	u32 mask;
 
@@ -626,6 +902,8 @@  static int a7xx_cp_init(struct msm_gpu *gpu)
 	OUT_PKT7(ring, CP_THREAD_CONTROL, 1);
 	OUT_RING(ring, BIT(27));
 
+	a7xx_patch_pwrup_reglist(gpu);
+
 	OUT_PKT7(ring, CP_ME_INIT, 7);
 
 	/* Use multiple HW contexts */
@@ -656,11 +934,11 @@  static int a7xx_cp_init(struct msm_gpu *gpu)
 
 	/* *Don't* send a power up reg list for concurrent binning (TODO) */
 	/* Lo address */
-	OUT_RING(ring, 0x00000000);
+	OUT_RING(ring, lower_32_bits(a6xx_gpu->pwrup_reglist_iova));
 	/* Hi address */
-	OUT_RING(ring, 0x00000000);
+	OUT_RING(ring, upper_32_bits(a6xx_gpu->pwrup_reglist_iova));
 	/* BIT(31) set => read the regs from the list */
-	OUT_RING(ring, 0x00000000);
+	OUT_RING(ring, BIT(31));
 
 	a6xx_flush(gpu, ring);
 	return a6xx_idle(gpu, ring) ? 0 : -EINVAL;
@@ -784,6 +1062,16 @@  static int a6xx_ucode_load(struct msm_gpu *gpu)
 		msm_gem_object_set_name(a6xx_gpu->shadow_bo, "shadow");
 	}
 
+	a6xx_gpu->pwrup_reglist_ptr = msm_gem_kernel_new(gpu->dev, PAGE_SIZE,
+							 MSM_BO_WC  | MSM_BO_MAP_PRIV,
+							 gpu->aspace, &a6xx_gpu->pwrup_reglist_bo,
+							 &a6xx_gpu->pwrup_reglist_iova);
+
+	if (IS_ERR(a6xx_gpu->pwrup_reglist_ptr))
+		return PTR_ERR(a6xx_gpu->pwrup_reglist_ptr);
+
+	msm_gem_object_set_name(a6xx_gpu->pwrup_reglist_bo, "pwrup_reglist");
+
 	return 0;
 }
 
@@ -1127,6 +1415,8 @@  static int hw_init(struct msm_gpu *gpu)
 	if (a6xx_gpu->shadow_bo) {
 		gpu_write64(gpu, REG_A6XX_CP_RB_RPTR_ADDR,
 			shadowptr(a6xx_gpu, gpu->rb[0]));
+		for (unsigned int i = 0; i < gpu->nr_rings; i++)
+			a6xx_gpu->shadow[i] = 0;
 	}
 
 	/* ..which means "always" on A7xx, also for BV shadow */
@@ -1135,6 +1425,8 @@  static int hw_init(struct msm_gpu *gpu)
 			    rbmemptr(gpu->rb[0], bv_rptr));
 	}
 
+	a6xx_preempt_hw_init(gpu);
+
 	/* Always come up on rb 0 */
 	a6xx_gpu->cur_ring = gpu->rb[0];
 
@@ -1180,6 +1472,10 @@  static int hw_init(struct msm_gpu *gpu)
 out:
 	if (adreno_has_gmu_wrapper(adreno_gpu))
 		return ret;
+
+	/* Last step - yield the ringbuffer */
+	a7xx_preempt_start(gpu);
+
 	/*
 	 * Tell the GMU that we are done touching the GPU and it can start power
 	 * management
@@ -1557,8 +1853,13 @@  static irqreturn_t a6xx_irq(struct msm_gpu *gpu)
 	if (status & A6XX_RBBM_INT_0_MASK_SWFUSEVIOLATION)
 		a7xx_sw_fuse_violation_irq(gpu);
 
-	if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS)
+	if (status & A6XX_RBBM_INT_0_MASK_CP_CACHE_FLUSH_TS) {
 		msm_gpu_retire(gpu);
+		a6xx_preempt_trigger(gpu);
+	}
+
+	if (status & A6XX_RBBM_INT_0_MASK_CP_SW)
+		a6xx_preempt_irq(gpu);
 
 	return IRQ_HANDLED;
 }
@@ -2165,6 +2466,8 @@  static const struct adreno_gpu_funcs funcs = {
 		.active_ring = a6xx_active_ring,
 		.irq = a6xx_irq,
 		.destroy = a6xx_destroy,
+		.submitqueue_setup = a6xx_preempt_submitqueue_setup,
+		.submitqueue_close = a6xx_preempt_submitqueue_close,
 #if defined(CONFIG_DRM_MSM_GPU_STATE)
 		.show = a6xx_show,
 #endif
@@ -2331,6 +2634,8 @@  struct msm_gpu *a6xx_gpu_init(struct drm_device *dev)
 				a6xx_fault_handler);
 
 	a6xx_calc_ubwc_config(adreno_gpu);
+	/* Set up the preemption specific bits and pieces for each ringbuffer */
+	a6xx_preempt_init(gpu);
 
 	return gpu;
 }
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
index e3e5c53ae8af..652e49f01428 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
@@ -12,6 +12,31 @@ 
 
 extern bool hang_debug;
 
+struct cpu_gpu_lock {
+	uint32_t gpu_req;
+	uint32_t cpu_req;
+	uint32_t turn;
+	union {
+		struct {
+			uint16_t list_length;
+			uint16_t list_offset;
+		};
+		struct {
+			uint8_t ifpc_list_len;
+			uint8_t preemption_list_len;
+			uint16_t dynamic_list_len;
+		};
+	};
+	uint64_t regs[62];
+};
+
+struct adreno_reglist_list {
+	/** @reg: List of register **/
+	const u32 *regs;
+	/** @count: Number of registers in the list **/
+	u32 count;
+};
+
 /**
  * struct a6xx_info - a6xx specific information from device table
  *
@@ -31,6 +56,24 @@  struct a6xx_gpu {
 	uint64_t sqe_iova;
 
 	struct msm_ringbuffer *cur_ring;
+	struct msm_ringbuffer *next_ring;
+
+	struct drm_gem_object *preempt_bo[MSM_GPU_MAX_RINGS];
+	void *preempt[MSM_GPU_MAX_RINGS];
+	uint64_t preempt_iova[MSM_GPU_MAX_RINGS];
+	uint32_t last_seqno[MSM_GPU_MAX_RINGS];
+
+	atomic_t preempt_state;
+	spinlock_t eval_lock;
+	struct timer_list preempt_timer;
+
+	unsigned int preempt_level;
+	bool uses_gmem;
+	bool skip_save_restore;
+
+	struct drm_gem_object *scratch_bo;
+	void *scratch_ptr;
+	uint64_t scratch_iova;
 
 	struct a6xx_gmu gmu;
 
@@ -38,6 +81,10 @@  struct a6xx_gpu {
 	uint64_t shadow_iova;
 	uint32_t *shadow;
 
+	struct drm_gem_object *pwrup_reglist_bo;
+	void *pwrup_reglist_ptr;
+	uint64_t pwrup_reglist_iova;
+
 	bool has_whereami;
 
 	void __iomem *llc_mmio;
@@ -49,6 +96,108 @@  struct a6xx_gpu {
 
 #define to_a6xx_gpu(x) container_of(x, struct a6xx_gpu, base)
 
+#define SCRATCH_USER_CTX_IOVA(ring_id, a6xx_gpu) \
+	(a6xx_gpu->scratch_iova + (ring_id * sizeof(uint64_t)))
+
+/*
+ * In order to do lockless preemption we use a simple state machine to progress
+ * through the process.
+ *
+ * PREEMPT_NONE - no preemption in progress.  Next state START.
+ * PREEMPT_START - The trigger is evaluating if preemption is possible. Next
+ * states: TRIGGERED, NONE
+ * PREEMPT_FINISH - An intermediate state before moving back to NONE. Next
+ * state: NONE.
+ * PREEMPT_TRIGGERED: A preemption has been executed on the hardware. Next
+ * states: FAULTED, PENDING
+ * PREEMPT_FAULTED: A preemption timed out (never completed). This will trigger
+ * recovery.  Next state: N/A
+ * PREEMPT_PENDING: Preemption complete interrupt fired - the callback is
+ * checking the success of the operation. Next state: FAULTED, NONE.
+ */
+
+enum a6xx_preempt_state {
+	PREEMPT_NONE = 0,
+	PREEMPT_START,
+	PREEMPT_FINISH,
+	PREEMPT_TRIGGERED,
+	PREEMPT_FAULTED,
+	PREEMPT_PENDING,
+};
+
+/*
+ * struct a6xx_preempt_record is a shared buffer between the microcode and the
+ * CPU to store the state for preemption. The record itself is much larger
+ * (2112k) but most of that is used by the CP for storage.
+ *
+ * There is a preemption record assigned per ringbuffer. When the CPU triggers a
+ * preemption, it fills out the record with the useful information (wptr, ring
+ * base, etc) and the microcode uses that information to set up the CP following
+ * the preemption.  When a ring is switched out, the CP will save the ringbuffer
+ * state back to the record. In this way, once the records are properly set up
+ * the CPU can quickly switch back and forth between ringbuffers by only
+ * updating a few registers (often only the wptr).
+ *
+ * These are the CPU aware registers in the record:
+ * @magic: Must always be 0xAE399D6EUL
+ * @info: Type of the record - written 0 by the CPU, updated by the CP
+ * @errno: preemption error record
+ * @data: Data field in YIELD and SET_MARKER packets, Written and used by CP
+ * @cntl: Value of RB_CNTL written by CPU, save/restored by CP
+ * @rptr: Value of RB_RPTR written by CPU, save/restored by CP
+ * @wptr: Value of RB_WPTR written by CPU, save/restored by CP
+ * @_pad: Reserved/padding
+ * @rptr_addr: Value of RB_RPTR_ADDR_LO|HI written by CPU, save/restored by CP
+ * @rbase: Value of RB_BASE written by CPU, save/restored by CP
+ * @counter: GPU address of the storage area for the preemption counters
+ */
+struct a6xx_preempt_record {
+	u32 magic;
+	u32 info;
+	u32 errno;
+	u32 data;
+	u32 cntl;
+	u32 rptr;
+	u32 wptr;
+	u32 _pad;
+	u64 rptr_addr;
+	u64 rbase;
+	u64 counter;
+	u64 bv_rptr_addr;
+};
+
+#define A6XX_PREEMPT_RECORD_MAGIC 0xAE399D6EUL
+
+#define PREEMPT_RECORD_SIZE_FALLBACK(size) \
+	((size) == 0 ? 4192 * SZ_1K : (size))
+
+#define PREEMPT_OFFSET_SMMU_INFO 0
+#define PREEMPT_OFFSET_PRIV_NON_SECURE (PREEMPT_OFFSET_SMMU_INFO + 4096)
+#define PREEMPT_OFFSET_PRIV_SECURE(size) \
+	(PREEMPT_OFFSET_PRIV_NON_SECURE + PREEMPT_RECORD_SIZE_FALLBACK(size))
+#define PREEMPT_SIZE(size) \
+	(PREEMPT_OFFSET_PRIV_SECURE(size) + PREEMPT_RECORD_SIZE_FALLBACK(size))
+
+/*
+ * The preemption counter block is a storage area for the value of the
+ * preemption counters that are saved immediately before context switch. We
+ * append it on to the end of the allocation for the preemption record.
+ */
+#define A6XX_PREEMPT_COUNTER_SIZE (16 * 4)
+
+#define A6XX_PREEMPT_USER_RECORD_SIZE (192 * 1024)
+
+struct a7xx_cp_smmu_info {
+	u32 magic;
+	u32 _pad4;
+	u64 ttbr0;
+	u32 asid;
+	u32 context_idr;
+	u32 context_bank;
+};
+
+#define GEN7_CP_SMMU_INFO_MAGIC 0x241350d5UL
+
 /*
  * Given a register and a count, return a value to program into
  * REG_CP_PROTECT_REG(n) - this will block both reads and writes for
@@ -106,6 +255,25 @@  int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
 int a6xx_gmu_wrapper_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node);
 void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu);
 
+void a6xx_preempt_init(struct msm_gpu *gpu);
+void a6xx_preempt_hw_init(struct msm_gpu *gpu);
+void a6xx_preempt_trigger(struct msm_gpu *gpu);
+void a6xx_preempt_irq(struct msm_gpu *gpu);
+void a6xx_preempt_fini(struct msm_gpu *gpu);
+int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
+		struct msm_gpu_submitqueue *queue);
+void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
+		struct msm_gpu_submitqueue *queue);
+
+/* Return true if we are in a preempt state */
+static inline bool a6xx_in_preempt(struct a6xx_gpu *a6xx_gpu)
+{
+	int preempt_state = atomic_read(&a6xx_gpu->preempt_state);
+
+	return !(preempt_state == PREEMPT_NONE ||
+			preempt_state == PREEMPT_FINISH);
+}
+
 void a6xx_gmu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp,
 		       bool suspended);
 unsigned long a6xx_gmu_get_freq(struct msm_gpu *gpu);
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_preempt.c b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
new file mode 100644
index 000000000000..0d402a3bcf5a
--- /dev/null
+++ b/drivers/gpu/drm/msm/adreno/a6xx_preempt.c
@@ -0,0 +1,434 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2018, The Linux Foundation. All rights reserved. */
+/* Copyright (c) 2023 Collabora, Ltd. */
+/* Copyright (c) 2024 Valve Corporation */
+
+#include "msm_gem.h"
+#include "a6xx_gpu.h"
+#include "a6xx_gmu.xml.h"
+#include "msm_mmu.h"
+
+#define FENCE_STATUS_WRITEDROPPED0_MASK 0x1
+#define FENCE_STATUS_WRITEDROPPED1_MASK 0x2
+
+/*
+ * Try to transition the preemption state from old to new. Return
+ * true on success or false if the original state wasn't 'old'
+ */
+static inline bool try_preempt_state(struct a6xx_gpu *a6xx_gpu,
+		enum a6xx_preempt_state old, enum a6xx_preempt_state new)
+{
+	enum a6xx_preempt_state cur = atomic_cmpxchg(&a6xx_gpu->preempt_state,
+		old, new);
+
+	return (cur == old);
+}
+
+/*
+ * Force the preemption state to the specified state.  This is used in cases
+ * where the current state is known and won't change
+ */
+static inline void set_preempt_state(struct a6xx_gpu *gpu,
+		enum a6xx_preempt_state new)
+{
+	/*
+	 * preempt_state may be read by other cores trying to trigger a
+	 * preemption or in the interrupt handler so barriers are needed
+	 * before...
+	 */
+	smp_mb__before_atomic();
+	atomic_set(&gpu->preempt_state, new);
+	/* ... and after*/
+	smp_mb__after_atomic();
+}
+
+/* Write the most recent wptr for the given ring into the hardware */
+static inline void update_wptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
+{
+	unsigned long flags;
+	uint32_t wptr, cur_wptr;
+
+	if (!ring)
+		return;
+
+	spin_lock_irqsave(&ring->preempt_lock, flags);
+
+	if (ring->skip_inline_wptr) {
+		wptr = get_wptr(ring);
+
+		gpu_write(gpu, REG_A6XX_CP_RB_WPTR, wptr);
+
+		ring->skip_inline_wptr = false;
+	}
+
+	spin_unlock_irqrestore(&ring->preempt_lock, flags);
+}
+
+/* Return the highest priority ringbuffer with something in it */
+static struct msm_ringbuffer *get_next_ring(struct msm_gpu *gpu)
+{
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+
+	unsigned long flags;
+	int i;
+
+	for (i = 0; i < gpu->nr_rings; i++) {
+		bool empty;
+		struct msm_ringbuffer *ring = gpu->rb[i];
+
+		spin_lock_irqsave(&ring->preempt_lock, flags);
+		empty = (get_wptr(ring) == gpu->funcs->get_rptr(gpu, ring));
+		if (!empty && ring == a6xx_gpu->cur_ring)
+			empty = ring->memptrs->fence == a6xx_gpu->last_seqno[i];
+		spin_unlock_irqrestore(&ring->preempt_lock, flags);
+
+		if (!empty)
+			return ring;
+	}
+
+	return NULL;
+}
+
+static void a6xx_preempt_timer(struct timer_list *t)
+{
+	struct a6xx_gpu *a6xx_gpu = from_timer(a6xx_gpu, t, preempt_timer);
+	struct msm_gpu *gpu = &a6xx_gpu->base.base;
+	struct drm_device *dev = gpu->dev;
+
+	if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_FAULTED))
+		return;
+
+	dev_err(dev->dev, "%s: preemption timed out\n", gpu->name);
+	kthread_queue_work(gpu->worker, &gpu->recover_work);
+}
+
+void a6xx_preempt_irq(struct msm_gpu *gpu)
+{
+	uint32_t status;
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+	struct drm_device *dev = gpu->dev;
+
+	if (!try_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED, PREEMPT_PENDING))
+		return;
+
+	/* Delete the preemption watchdog timer */
+	del_timer(&a6xx_gpu->preempt_timer);
+
+	/*
+	 * The hardware should be setting the stop bit of CP_CONTEXT_SWITCH_CNTL
+	 * to zero before firing the interrupt, but there is a non zero chance
+	 * of a hardware condition or a software race that could set it again
+	 * before we have a chance to finish. If that happens, log and go for
+	 * recovery
+	 */
+	status = gpu_read(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL);
+	if (unlikely(status & 0x1)) {
+		DRM_DEV_ERROR(&gpu->pdev->dev,
+					  "!!!!!!!!!!!!!!!! preemption faulted !!!!!!!!!!!!!! irq\n");
+		set_preempt_state(a6xx_gpu, PREEMPT_FAULTED);
+		dev_err(dev->dev, "%s: Preemption failed to complete\n",
+			gpu->name);
+		kthread_queue_work(gpu->worker, &gpu->recover_work);
+		return;
+	}
+
+	a6xx_gpu->cur_ring = a6xx_gpu->next_ring;
+	a6xx_gpu->next_ring = NULL;
+
+	/* Make sure the write to cur_ring is posted before the change in state */
+	wmb();
+
+	set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
+
+	update_wptr(gpu, a6xx_gpu->cur_ring);
+
+	set_preempt_state(a6xx_gpu, PREEMPT_NONE);
+
+	/*
+	 * Retrigger preemption to avoid a deadlock that might occur when preemption
+	 * is skipped due to it being already in flight when requested.
+	 */
+	a6xx_preempt_trigger(gpu);
+}
+
+void a6xx_preempt_hw_init(struct msm_gpu *gpu)
+{
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+	int i;
+
+	/* No preemption if we only have one ring */
+	if (gpu->nr_rings == 1)
+		return;
+
+	for (i = 0; i < gpu->nr_rings; i++) {
+		struct a6xx_preempt_record *record_ptr =
+			a6xx_gpu->preempt[i] + PREEMPT_OFFSET_PRIV_NON_SECURE;
+		record_ptr->wptr = 0;
+		record_ptr->rptr = 0;
+		record_ptr->rptr_addr = shadowptr(a6xx_gpu, gpu->rb[i]);
+		record_ptr->info = 0;
+		record_ptr->data = 0;
+		record_ptr->rbase = gpu->rb[i]->iova;
+	}
+
+	/* Write a 0 to signal that we aren't switching pagetables */
+	gpu_write64(gpu, REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO, 0);
+
+	/* Enable the GMEM save/restore feature for preemption */
+	gpu_write(gpu, REG_A6XX_RB_CONTEXT_SWITCH_GMEM_SAVE_RESTORE, 0x1);
+
+	/* Reset the preemption state */
+	set_preempt_state(a6xx_gpu, PREEMPT_NONE);
+
+	spin_lock_init(&a6xx_gpu->eval_lock);
+
+	/* Always come up on rb 0 */
+	a6xx_gpu->cur_ring = gpu->rb[0];
+}
+
+void a6xx_preempt_trigger(struct msm_gpu *gpu)
+{
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+	u64 preempt_offset_priv_secure;
+	unsigned long flags;
+	struct msm_ringbuffer *ring;
+	uint64_t user_ctx_iova;
+	unsigned int cntl;
+
+	if (gpu->nr_rings == 1)
+		return;
+
+	/*
+	 * Lock to make sure another thread attempting preemption doesn't skip it
+	 * while we are still evaluating the next ring. This makes sure the other
+	 * thread does start preemption if we abort it and avoids a soft lock.
+	 */
+	spin_lock_irqsave(&a6xx_gpu->eval_lock, flags);
+
+	/*
+	 * Try to start preemption by moving from NONE to START. If
+	 * unsuccessful, a preemption is already in flight
+	 */
+	if (!try_preempt_state(a6xx_gpu, PREEMPT_NONE, PREEMPT_START)) {
+		spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
+		return;
+	}
+
+	cntl = (((a6xx_gpu->preempt_level << 6) & 0xC0) |
+		((a6xx_gpu->skip_save_restore << 9) & 0x200) |
+		((a6xx_gpu->uses_gmem << 8) & 0x100) | 0x1);
+
+	/* Get the next ring to preempt to */
+	ring = get_next_ring(gpu);
+
+	/*
+	 * If no ring is populated or the highest priority ring is the current
+	 * one do nothing except to update the wptr to the latest and greatest
+	 */
+	if (!ring || (a6xx_gpu->cur_ring == ring)) {
+		set_preempt_state(a6xx_gpu, PREEMPT_FINISH);
+		update_wptr(gpu, a6xx_gpu->cur_ring);
+		set_preempt_state(a6xx_gpu, PREEMPT_NONE);
+		spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
+		return;
+	}
+
+	spin_unlock_irqrestore(&a6xx_gpu->eval_lock, flags);
+
+	spin_lock_irqsave(&ring->preempt_lock, flags);
+
+	struct a7xx_cp_smmu_info *smmu_info_ptr =
+		a6xx_gpu->preempt[ring->id] + PREEMPT_OFFSET_SMMU_INFO;
+	struct a6xx_preempt_record *record_ptr =
+		a6xx_gpu->preempt[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE;
+	u64 ttbr0 = ring->memptrs->ttbr0;
+	u32 context_idr = ring->memptrs->context_idr;
+
+	smmu_info_ptr->ttbr0 = ttbr0;
+	smmu_info_ptr->context_idr = context_idr;
+	record_ptr->wptr = get_wptr(ring);
+
+	/*
+	 * The GPU will write the wptr we set above when we preempt. Reset
+	 * skip_inline_wptr to make sure that we don't write WPTR to the same
+	 * thing twice. It's still possible subsequent submissions will update
+	 * wptr again, in which case they will set the flag to true. This has
+	 * to be protected by the lock for setting the flag and updating wptr
+	 * to be atomic.
+	 */
+	ring->skip_inline_wptr = false;
+
+	spin_unlock_irqrestore(&ring->preempt_lock, flags);
+
+	gpu_write64(gpu,
+		REG_A6XX_CP_CONTEXT_SWITCH_SMMU_INFO,
+		a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_SMMU_INFO);
+
+	gpu_write64(gpu,
+		REG_A6XX_CP_CONTEXT_SWITCH_PRIV_NON_SECURE_RESTORE_ADDR,
+		a6xx_gpu->preempt_iova[ring->id] + PREEMPT_OFFSET_PRIV_NON_SECURE);
+
+	preempt_offset_priv_secure =
+		PREEMPT_OFFSET_PRIV_SECURE(adreno_gpu->info->preempt_record_size);
+	gpu_write64(gpu,
+		REG_A6XX_CP_CONTEXT_SWITCH_PRIV_SECURE_RESTORE_ADDR,
+		a6xx_gpu->preempt_iova[ring->id] + preempt_offset_priv_secure);
+
+	/*
+	 * Use the user context iova from the scratch memory that the CP may
+	 * have written as part of the ring switch out.
+	 */
+	user_ctx_iova = *((uint64_t *)a6xx_gpu->scratch_ptr + ring->id);
+
+	gpu_write64(gpu,
+		REG_A6XX_CP_CONTEXT_SWITCH_NON_PRIV_RESTORE_ADDR,
+		user_ctx_iova);
+
+	a6xx_gpu->next_ring = ring;
+
+	/* Start a timer to catch a stuck preemption */
+	mod_timer(&a6xx_gpu->preempt_timer, jiffies + msecs_to_jiffies(10000));
+
+	/* Set the preemption state to triggered */
+	set_preempt_state(a6xx_gpu, PREEMPT_TRIGGERED);
+
+	/* Make sure any previous writes to WPTR are posted */
+	gpu_read(gpu, REG_A6XX_CP_RB_WPTR);
+
+	/* Make sure everything is written before hitting the button */
+	wmb();
+
+	/* Trigger the preemption */
+	gpu_write(gpu, REG_A6XX_CP_CONTEXT_SWITCH_CNTL, cntl);
+}
+
+static int preempt_init_ring(struct a6xx_gpu *a6xx_gpu,
+		struct msm_ringbuffer *ring)
+{
+	struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
+	struct msm_gpu *gpu = &adreno_gpu->base;
+	struct drm_gem_object *bo = NULL;
+	phys_addr_t ttbr;
+	u64 iova = 0;
+	void *ptr;
+	int asid;
+
+	ptr = msm_gem_kernel_new(gpu->dev,
+		PREEMPT_SIZE(adreno_gpu->info->preempt_record_size),
+		MSM_BO_WC | MSM_BO_MAP_PRIV, gpu->aspace, &bo, &iova);
+
+	memset(ptr, 0, PREEMPT_SIZE(adreno_gpu->info->preempt_record_size));
+
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
+
+	a6xx_gpu->preempt_bo[ring->id] = bo;
+	a6xx_gpu->preempt_iova[ring->id] = iova;
+	a6xx_gpu->preempt[ring->id] = ptr;
+
+	struct a7xx_cp_smmu_info *smmu_info_ptr = ptr + PREEMPT_OFFSET_SMMU_INFO;
+	struct a6xx_preempt_record *record_ptr = ptr + PREEMPT_OFFSET_PRIV_NON_SECURE;
+
+	msm_iommu_pagetable_params(gpu->aspace->mmu, &ttbr, &asid);
+
+	smmu_info_ptr->magic = GEN7_CP_SMMU_INFO_MAGIC;
+	smmu_info_ptr->ttbr0 = ttbr;
+	smmu_info_ptr->asid = 0xdecafbad;
+	smmu_info_ptr->context_idr = 0;
+
+	/* Set up the defaults on the preemption record */
+	record_ptr->magic = A6XX_PREEMPT_RECORD_MAGIC;
+	record_ptr->info = 0;
+	record_ptr->data = 0;
+	record_ptr->rptr = 0;
+	record_ptr->wptr = 0;
+	record_ptr->cntl = MSM_GPU_RB_CNTL_DEFAULT;
+	record_ptr->rbase = ring->iova;
+	record_ptr->counter = 0;
+	record_ptr->bv_rptr_addr = rbmemptr(ring, bv_rptr);
+
+	return 0;
+}
+
+void a6xx_preempt_fini(struct msm_gpu *gpu)
+{
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+	int i;
+
+	for (i = 0; i < gpu->nr_rings; i++)
+		msm_gem_kernel_put(a6xx_gpu->preempt_bo[i], gpu->aspace);
+}
+
+void a6xx_preempt_init(struct msm_gpu *gpu)
+{
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+	int i;
+
+	/* No preemption if we only have one ring */
+	if (gpu->nr_rings <= 1)
+		return;
+
+	for (i = 0; i < gpu->nr_rings; i++) {
+		if (preempt_init_ring(a6xx_gpu, gpu->rb[i]))
+			goto fail;
+	}
+
+	/* TODO: make this configurable? */
+	a6xx_gpu->preempt_level = 1;
+	a6xx_gpu->uses_gmem = 1;
+	a6xx_gpu->skip_save_restore = 1;
+
+	a6xx_gpu->scratch_ptr  = msm_gem_kernel_new(gpu->dev,
+			gpu->nr_rings * sizeof(uint64_t), MSM_BO_WC,
+			gpu->aspace, &a6xx_gpu->scratch_bo,
+			&a6xx_gpu->scratch_iova);
+
+	if (IS_ERR(a6xx_gpu->scratch_ptr))
+		goto fail;
+
+	timer_setup(&a6xx_gpu->preempt_timer, a6xx_preempt_timer, 0);
+
+	return;
+fail:
+	/*
+	 * On any failure our adventure is over. Clean up and
+	 * set nr_rings to 1 to force preemption off
+	 */
+	a6xx_preempt_fini(gpu);
+	gpu->nr_rings = 1;
+
+	return;
+}
+
+void a6xx_preempt_submitqueue_close(struct msm_gpu *gpu,
+		struct msm_gpu_submitqueue *queue)
+{
+	if (!queue->bo)
+		return;
+
+	msm_gem_kernel_put(queue->bo, gpu->aspace);
+}
+
+int a6xx_preempt_submitqueue_setup(struct msm_gpu *gpu,
+		struct msm_gpu_submitqueue *queue)
+{
+	void *ptr;
+
+	/*
+	 * Create a per submitqueue buffer for the CP to save and restore user
+	 * specific information such as the VPC streamout data.
+	 */
+	ptr = msm_gem_kernel_new(gpu->dev, A6XX_PREEMPT_USER_RECORD_SIZE,
+			MSM_BO_WC, gpu->aspace, &queue->bo, &queue->bo_iova);
+
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
+
+	return 0;
+}
diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.h b/drivers/gpu/drm/msm/msm_ringbuffer.h
index 40791b2ade46..7dde6a312511 100644
--- a/drivers/gpu/drm/msm/msm_ringbuffer.h
+++ b/drivers/gpu/drm/msm/msm_ringbuffer.h
@@ -36,6 +36,7 @@  struct msm_rbmemptrs {
 
 	volatile struct msm_gpu_submit_stats stats[MSM_GPU_SUBMIT_STATS_COUNT];
 	volatile u64 ttbr0;
+	volatile u32 context_idr;
 };
 
 struct msm_cp_state {
@@ -100,6 +101,12 @@  struct msm_ringbuffer {
 	 * preemption.  Can be aquired from irq context.
 	 */
 	spinlock_t preempt_lock;
+
+	/*
+	 * Whether we skipped writing wptr and it needs to be updated in the
+	 * future when the ring becomes current.
+	 */
+	bool skip_inline_wptr;
 };
 
 struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int id,