| Message ID | 20250217-mhi_bw_up-v1-6-9bad1e42bdb1@oss.qualcomm.com (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Jeff Johnson |
| Headers | show |
| Series | bus: mhi: host: Add support for mhi bus bw | expand |
On Mon, 17 Feb 2025, Krishna Chaitanya Chundru wrote: > As per MHI spec sec 14, MHI supports bandwidth scaling to reduce power > consumption. MHI bandwidth scaling is advertised in devices that contain > the bandwidth scaling capability registers. If enabled, the device > aggregates bandwidth requirements and sends them to the host in the form > of an event. After the host performs the bandwidth switch, it sends an > acknowledgment by ringing a doorbell. > > if the host supports bandwidth scaling events, then it must set > BW_CFG.ENABLED bit, set BW_CFG.DB_CHAN_ID to the channel ID to the > doorbell that will be used by the host to communicate the bandwidth > scaling status and BW_CFG.ER_INDEX to the index for the event ring > to which the device should send bandwidth scaling request in the > bandwidth scaling capability register. > > As part of mmio init check if the bw scale capability is present or not, > if present advertise host supports bw scale by setting all the required > fields. > > MHI layer will only forward the bw scaling request to the controller > driver, it is responsibility of the controller driver to do actual bw > scaling and then pass status to the MHI. MHI will response back to the > device based up on the status of the bw scale received. > > Add a new get_misc_doorbell() to get doorbell for misc capabilities to > use the doorbell with mhi events like MHI BW scale etc. > > Use workqueue & mutex for the bw scale events as the pci_set_target_speed() > which will called by the mhi controller driver can sleep. > > Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com> > --- > drivers/bus/mhi/common.h | 14 ++++++ > drivers/bus/mhi/host/init.c | 64 ++++++++++++++++++++++++- > drivers/bus/mhi/host/internal.h | 7 ++- > drivers/bus/mhi/host/main.c | 102 +++++++++++++++++++++++++++++++++++++++- > drivers/bus/mhi/host/pm.c | 10 +++- > include/linux/mhi.h | 13 +++++ > 6 files changed, 204 insertions(+), 6 deletions(-) > > diff --git a/drivers/bus/mhi/common.h b/drivers/bus/mhi/common.h > index eedac801b800..b900199fab10 100644 > --- a/drivers/bus/mhi/common.h > +++ b/drivers/bus/mhi/common.h > @@ -208,6 +208,20 @@ > #define MHI_RSCTRE_DATA_DWORD1 cpu_to_le32(FIELD_PREP(GENMASK(23, 16), \ > MHI_PKT_TYPE_COALESCING)) > > +/* MHI Bandwidth scaling offsets */ > +#define BW_SCALE_CFG_OFFSET (0x04) > +#define BW_SCALE_CFG_CHAN_DB_ID_SHIFT (25) > +#define BW_SCALE_CFG_ENABLED_MASK BIT(24) > +#define BW_SCALE_CFG_ENABLED_SHIFT (24) > +#define BW_SCALE_CFG_ER_ID_SHIFT (19) > + > +#define BW_SCALE_CAP_ID (3) > +#define MHI_TRE_GET_EV_BW_REQ_SEQ(tre) (((tre)->dword[0] >> 8) & 0xFF) This looks open-coded FIELD_GET(). Add the field define and use FIELD_GET() with it. > + > +#define MHI_BW_SCALE_RESULT(status, seq) (((status) & 0xF) << 8 | \ > + ((seq) & 0xFF)) 2x FIELD_PREP(). > +#define MHI_BW_SCALE_NACK 0xF > + > enum mhi_pkt_type { > MHI_PKT_TYPE_INVALID = 0x0, > MHI_PKT_TYPE_NOOP_CMD = 0x1, > diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c > index 0b14b665ed15..f15c79f85d13 100644 > --- a/drivers/bus/mhi/host/init.c > +++ b/drivers/bus/mhi/host/init.c > @@ -496,10 +496,56 @@ static int mhi_get_capability_offset(struct mhi_controller *mhi_cntrl, u32 capab > return -ENXIO; > } > > +/* to be used only if a single event ring with the type is present */ > +static int mhi_get_er_index(struct mhi_controller *mhi_cntrl, > + enum mhi_er_data_type type) > +{ > + struct mhi_event *mhi_event = mhi_cntrl->mhi_event; > + int i; > + > + /* find event ring for requested type */ > + for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) { > + if (mhi_event->data_type == type) > + return mhi_event->er_index; > + } > + > + return -ENOENT; > +} > + > +static int mhi_init_bw_scale(struct mhi_controller *mhi_cntrl, > + int bw_scale_db) > +{ > + struct device *dev = &mhi_cntrl->mhi_dev->dev; > + u32 bw_cfg_offset, val = 0; > + int ret, er_index; > + > + ret = mhi_get_capability_offset(mhi_cntrl, BW_SCALE_CAP_ID, > + &bw_cfg_offset); > + if (ret) > + return ret; > + > + /* No ER configured to support BW scale */ > + er_index = mhi_get_er_index(mhi_cntrl, MHI_ER_BW_SCALE); > + if (er_index < 0) > + return er_index; > + > + bw_cfg_offset += BW_SCALE_CFG_OFFSET; > + > + /* advertise host support */ > + val = ((bw_scale_db << BW_SCALE_CFG_CHAN_DB_ID_SHIFT) | > + BW_SCALE_CFG_ENABLED_MASK | (er_index << BW_SCALE_CFG_ER_ID_SHIFT)); Please name the fields with defines and use FIELD_PREP(). And remove _SHIFT ending defines. Also make the file does correct #include for FIELD_PREP/GET if not yet there. > + mhi_write_reg(mhi_cntrl, mhi_cntrl->regs, bw_cfg_offset, val); > + > + dev_info(dev, "Bandwidth scaling setup complete. Event ring:%d\n", > + er_index); This sound like dev_dbg() to me. What's the value for user in normal scenarios? > + return 0; > +} > + > int mhi_init_mmio(struct mhi_controller *mhi_cntrl) > { > u32 val; > - int i, ret; > + int i, ret, doorbell; > struct mhi_chan *mhi_chan; > struct mhi_event *mhi_event; > void __iomem *base = mhi_cntrl->regs; > @@ -633,6 +679,16 @@ int mhi_init_mmio(struct mhi_controller *mhi_cntrl) > return ret; > } > > + if (mhi_cntrl->get_misc_doorbell) > + doorbell = mhi_cntrl->get_misc_doorbell(mhi_cntrl, MHI_ER_BW_SCALE); > + > + if (doorbell > 0) { > + ret = mhi_init_bw_scale(mhi_cntrl, doorbell); > + if (!ret) > + mhi_cntrl->bw_scale_db = base + val + (8 * doorbell); > + else > + dev_warn(dev, "BW scale setup failure\n"); Is it okay to return 0 in this case? > + } > return 0; > } > > @@ -778,6 +834,9 @@ static int parse_ev_cfg(struct mhi_controller *mhi_cntrl, > case MHI_ER_CTRL: > mhi_event->process_event = mhi_process_ctrl_ev_ring; > break; > + case MHI_ER_BW_SCALE: > + mhi_event->process_event = mhi_process_bw_scale_ev_ring; > + break; > default: > dev_err(dev, "Event Ring type not supported\n"); > goto error_ev_cfg; > @@ -1012,9 +1071,12 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl, > > mhi_event->mhi_cntrl = mhi_cntrl; > spin_lock_init(&mhi_event->lock); > + mutex_init(&mhi_event->mutex); > if (mhi_event->data_type == MHI_ER_CTRL) > tasklet_init(&mhi_event->task, mhi_ctrl_ev_task, > (ulong)mhi_event); > + else if (mhi_event->data_type == MHI_ER_BW_SCALE) > + INIT_WORK(&mhi_event->work, mhi_process_ev_work); > else > tasklet_init(&mhi_event->task, mhi_ev_task, > (ulong)mhi_event); > diff --git a/drivers/bus/mhi/host/internal.h b/drivers/bus/mhi/host/internal.h > index 3134f111be35..bf7c6a7c9383 100644 > --- a/drivers/bus/mhi/host/internal.h > +++ b/drivers/bus/mhi/host/internal.h > @@ -241,6 +241,8 @@ struct mhi_event { > struct mhi_ring ring; > struct db_cfg db_cfg; > struct tasklet_struct task; > + struct work_struct work; > + struct mutex mutex; > spinlock_t lock; > int (*process_event)(struct mhi_controller *mhi_cntrl, > struct mhi_event *mhi_event, > @@ -403,7 +405,8 @@ int mhi_process_data_event_ring(struct mhi_controller *mhi_cntrl, > struct mhi_event *mhi_event, u32 event_quota); > int mhi_process_ctrl_ev_ring(struct mhi_controller *mhi_cntrl, > struct mhi_event *mhi_event, u32 event_quota); > - > +int mhi_process_bw_scale_ev_ring(struct mhi_controller *mhi_cntrl, > + struct mhi_event *mhi_event, u32 event_quota); > /* ISR handlers */ > irqreturn_t mhi_irq_handler(int irq_number, void *dev); > irqreturn_t mhi_intvec_threaded_handler(int irq_number, void *dev); > @@ -419,5 +422,5 @@ void mhi_unmap_single_no_bb(struct mhi_controller *mhi_cntrl, > struct mhi_buf_info *buf_info); > void mhi_unmap_single_use_bb(struct mhi_controller *mhi_cntrl, > struct mhi_buf_info *buf_info); > - > +void mhi_process_ev_work(struct work_struct *work); > #endif /* _MHI_INT_H */ > diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c > index 4de75674f193..a6732bbead44 100644 > --- a/drivers/bus/mhi/host/main.c > +++ b/drivers/bus/mhi/host/main.c > @@ -472,7 +472,10 @@ irqreturn_t mhi_irq_handler(int irq_number, void *dev) > if (mhi_dev) > mhi_notify(mhi_dev, MHI_CB_PENDING_DATA); > } else { > - tasklet_schedule(&mhi_event->task); > + if (mhi_event->data_type == MHI_ER_BW_SCALE) > + queue_work(mhi_cntrl->hiprio_wq, &mhi_event->work); > + else > + tasklet_schedule(&mhi_event->task); > } > > return IRQ_HANDLED; > @@ -1049,6 +1052,103 @@ int mhi_process_data_event_ring(struct mhi_controller *mhi_cntrl, > return count; > } > > +/* dedicated bw scale event ring processing */ > +int mhi_process_bw_scale_ev_ring(struct mhi_controller *mhi_cntrl, > + struct mhi_event *mhi_event, u32 event_quota) > +{ > + struct mhi_event_ctxt *er_ctxt = &mhi_cntrl->mhi_ctxt->er_ctxt[mhi_event->er_index]; > + struct device *dev = &mhi_cntrl->mhi_dev->dev; > + struct mhi_ring *ev_ring = &mhi_event->ring; > + dma_addr_t ptr = le64_to_cpu(er_ctxt->rp); > + u32 response = MHI_BW_SCALE_NACK; > + struct mhi_ring_element *dev_rp; > + struct mhi_link_info link_info; > + int ret = -EINVAL; > + > + if (unlikely(MHI_EVENT_ACCESS_INVALID(mhi_cntrl->pm_state))) { > + ret = -EIO; > + goto exit_bw_scale_process; > + } > + > + if (!MHI_IN_MISSION_MODE(mhi_cntrl->ee)) > + goto exit_bw_scale_process; > + > + if (!is_valid_ring_ptr(ev_ring, ptr)) { > + dev_err(dev, > + "Event ring rp points outside of the event ring\n"); > + ret = -EIO; > + goto exit_bw_scale_process; > + } > + > + dev_rp = mhi_to_virtual(ev_ring, ptr); > + > + /* if rp points to base, we need to wrap it around */ > + if (dev_rp == ev_ring->base) > + dev_rp = ev_ring->base + ev_ring->len; > + dev_rp--; > + > + /* fast forward to currently processed element and recycle er */ > + ev_ring->rp = dev_rp; > + ev_ring->wp = dev_rp - 1; > + if (ev_ring->wp < ev_ring->base) > + ev_ring->wp = ev_ring->base + ev_ring->len - ev_ring->el_size; > + mhi_recycle_ev_ring_element(mhi_cntrl, ev_ring); > + > + if (WARN_ON(MHI_TRE_GET_EV_TYPE(dev_rp) != MHI_PKT_TYPE_BW_REQ_EVENT)) { > + dev_err(dev, "!BW SCALE REQ event\n"); > + goto exit_bw_scale_process; > + } > + > + link_info.target_link_speed = MHI_TRE_GET_EV_LINKSPEED(dev_rp); > + link_info.target_link_width = MHI_TRE_GET_EV_LINKWIDTH(dev_rp); > + link_info.sequence_num = MHI_TRE_GET_EV_BW_REQ_SEQ(dev_rp); > + > + dev_info(dev, "Received BW_REQ with seq:%d link speed:0x%x width:0x%x\n", > + link_info.sequence_num, > + link_info.target_link_speed, > + link_info.target_link_width); > + > + /* bring host and device out of suspended states */ > + ret = mhi_device_get_sync(mhi_cntrl->mhi_dev); > + if (ret) > + goto exit_bw_scale_process; > + > + mhi_cntrl->runtime_get(mhi_cntrl); > + > + ret = mhi_cntrl->bw_scale(mhi_cntrl, &link_info); > + if (!ret) > + response = 0; > + > + response = MHI_BW_SCALE_RESULT(response, link_info.sequence_num); > + > + write_lock_bh(&mhi_cntrl->pm_lock); > + mhi_write_reg(mhi_cntrl, mhi_cntrl->bw_scale_db, 0, response); > + write_unlock_bh(&mhi_cntrl->pm_lock); > + > + mhi_cntrl->runtime_put(mhi_cntrl); > + mhi_device_put(mhi_cntrl->mhi_dev); > + > +exit_bw_scale_process: > + dev_info(dev, "exit er_index:%u ret:%d\n", mhi_event->er_index, ret); There's zero value for normal user with something as obscure as this, make it dev_dbg(). > + return ret; > +} > + > +void mhi_process_ev_work(struct work_struct *work) > +{ > + struct mhi_event *mhi_event = container_of(work, struct mhi_event, > + work); > + > + struct mhi_controller *mhi_cntrl = mhi_event->mhi_cntrl; > + > + if (unlikely(MHI_EVENT_ACCESS_INVALID(mhi_cntrl->pm_state))) > + return; > + > + mutex_lock(&mhi_event->mutex); guard()() > + mhi_event->process_event(mhi_cntrl, mhi_event, U32_MAX); > + mutex_unlock(&mhi_event->mutex); > +} > + > void mhi_ev_task(unsigned long data) > { > struct mhi_event *mhi_event = (struct mhi_event *)data; > diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c > index 11c0e751f223..9c848ca582f0 100644 > --- a/drivers/bus/mhi/host/pm.c > +++ b/drivers/bus/mhi/host/pm.c > @@ -523,7 +523,10 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl, > if (mhi_event->offload_ev) > continue; > disable_irq(mhi_cntrl->irq[mhi_event->irq]); > - tasklet_kill(&mhi_event->task); > + if (mhi_event->data_type == MHI_ER_BW_SCALE) > + cancel_work_sync(&mhi_event->work); > + else > + tasklet_kill(&mhi_event->task); > } > > /* Release lock and wait for all pending threads to complete */ > @@ -670,7 +673,10 @@ static void mhi_pm_sys_error_transition(struct mhi_controller *mhi_cntrl) > for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) { > if (mhi_event->offload_ev) > continue; > - tasklet_kill(&mhi_event->task); > + if (mhi_event->data_type == MHI_ER_BW_SCALE) > + cancel_work_sync(&mhi_event->work); > + else > + tasklet_kill(&mhi_event->task); > } > > /* Release lock and wait for all pending threads to complete */ > diff --git a/include/linux/mhi.h b/include/linux/mhi.h > index 059dc94d20bb..d9bf88c35d14 100644 > --- a/include/linux/mhi.h > +++ b/include/linux/mhi.h > @@ -102,10 +102,12 @@ struct image_info { > * struct mhi_link_info - BW requirement > * target_link_speed - Link speed as defined by TLS bits in LinkControl reg > * target_link_width - Link width as defined by NLW bits in LinkStatus reg > + * sequence_num - used by device to track bw requests sent to host > */ > struct mhi_link_info { > unsigned int target_link_speed; > unsigned int target_link_width; > + int sequence_num; > }; > > /** > @@ -183,10 +185,12 @@ enum mhi_ch_ee_mask { > * enum mhi_er_data_type - Event ring data types > * @MHI_ER_DATA: Only client data over this ring > * @MHI_ER_CTRL: MHI control data and client data > + * @MHI_ER_BW_SCALE: MHI controller bandwidth scale functionality > */ > enum mhi_er_data_type { > MHI_ER_DATA, > MHI_ER_CTRL, > + MHI_ER_BW_SCALE, > }; > > /** > @@ -299,6 +303,7 @@ struct mhi_controller_config { > * @bhi: Points to base of MHI BHI register space > * @bhie: Points to base of MHI BHIe register space > * @wake_db: MHI WAKE doorbell register address > + * @wake_db: MHI BW_SCALE doorbell register address > * @iova_start: IOMMU starting address for data (required) > * @iova_stop: IOMMU stop address for data (required) > * @fw_image: Firmware image name for normal booting (optional) > @@ -355,6 +360,8 @@ struct mhi_controller_config { > * @write_reg: Write a MHI register via the physical link (required) > * @reset: Controller specific reset function (optional) > * @edl_trigger: CB function to trigger EDL mode (optional) > + * @get_misc_doobell: function to get doorbell used for MISC feature like BW scale etc (optional) > + * @bw_scale: CB function for passing BW scale info (optional) > * @buffer_len: Bounce buffer length > * @index: Index of the MHI controller instance > * @bounce_buf: Use of bounce buffer > @@ -376,6 +383,7 @@ struct mhi_controller { > void __iomem *bhi; > void __iomem *bhie; > void __iomem *wake_db; > + void __iomem *bw_scale_db; > > dma_addr_t iova_start; > dma_addr_t iova_stop; > @@ -440,6 +448,11 @@ struct mhi_controller { > void (*reset)(struct mhi_controller *mhi_cntrl); > int (*edl_trigger)(struct mhi_controller *mhi_cntrl); > > + int (*get_misc_doorbell)(struct mhi_controller *mhi_cntrl, > + enum mhi_er_data_type type); > + int (*bw_scale)(struct mhi_controller *mhi_cntrl, > + struct mhi_link_info *link_info); > + > size_t buffer_len; > int index; > bool bounce_buf; > >
Hi Krishna, kernel test robot noticed the following build warnings: [auto build test WARNING on 0ad2507d5d93f39619fc42372c347d6006b64319] url: https://github.com/intel-lab-lkp/linux/commits/Krishna-Chaitanya-Chundru/PCI-update-current-bus-speed-as-part-of-pci_bus_add_devices/20250217-144050 base: 0ad2507d5d93f39619fc42372c347d6006b64319 patch link: https://lore.kernel.org/r/20250217-mhi_bw_up-v1-6-9bad1e42bdb1%40oss.qualcomm.com patch subject: [PATCH 6/8] bus: mhi: host: Add support for Bandwidth scale config: x86_64-buildonly-randconfig-006-20250217 (https://download.01.org/0day-ci/archive/20250217/202502171823.5VC7a1E6-lkp@intel.com/config) compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250217/202502171823.5VC7a1E6-lkp@intel.com/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 <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202502171823.5VC7a1E6-lkp@intel.com/ All warnings (new ones prefixed by >>): >> drivers/bus/mhi/host/init.c:682:6: warning: variable 'doorbell' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] 682 | if (mhi_cntrl->get_misc_doorbell) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/bus/mhi/host/init.c:685:6: note: uninitialized use occurs here 685 | if (doorbell > 0) { | ^~~~~~~~ drivers/bus/mhi/host/init.c:682:2: note: remove the 'if' if its condition is always true 682 | if (mhi_cntrl->get_misc_doorbell) | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 683 | doorbell = mhi_cntrl->get_misc_doorbell(mhi_cntrl, MHI_ER_BW_SCALE); drivers/bus/mhi/host/init.c:548:22: note: initialize the variable 'doorbell' to silence this warning 548 | int i, ret, doorbell; | ^ | = 0 1 warning generated. vim +682 drivers/bus/mhi/host/init.c 544 545 int mhi_init_mmio(struct mhi_controller *mhi_cntrl) 546 { 547 u32 val; 548 int i, ret, doorbell; 549 struct mhi_chan *mhi_chan; 550 struct mhi_event *mhi_event; 551 void __iomem *base = mhi_cntrl->regs; 552 struct device *dev = &mhi_cntrl->mhi_dev->dev; 553 struct { 554 u32 offset; 555 u32 val; 556 } reg_info[] = { 557 { 558 CCABAP_HIGHER, 559 upper_32_bits(mhi_cntrl->mhi_ctxt->chan_ctxt_addr), 560 }, 561 { 562 CCABAP_LOWER, 563 lower_32_bits(mhi_cntrl->mhi_ctxt->chan_ctxt_addr), 564 }, 565 { 566 ECABAP_HIGHER, 567 upper_32_bits(mhi_cntrl->mhi_ctxt->er_ctxt_addr), 568 }, 569 { 570 ECABAP_LOWER, 571 lower_32_bits(mhi_cntrl->mhi_ctxt->er_ctxt_addr), 572 }, 573 { 574 CRCBAP_HIGHER, 575 upper_32_bits(mhi_cntrl->mhi_ctxt->cmd_ctxt_addr), 576 }, 577 { 578 CRCBAP_LOWER, 579 lower_32_bits(mhi_cntrl->mhi_ctxt->cmd_ctxt_addr), 580 }, 581 { 582 MHICTRLBASE_HIGHER, 583 upper_32_bits(mhi_cntrl->iova_start), 584 }, 585 { 586 MHICTRLBASE_LOWER, 587 lower_32_bits(mhi_cntrl->iova_start), 588 }, 589 { 590 MHIDATABASE_HIGHER, 591 upper_32_bits(mhi_cntrl->iova_start), 592 }, 593 { 594 MHIDATABASE_LOWER, 595 lower_32_bits(mhi_cntrl->iova_start), 596 }, 597 { 598 MHICTRLLIMIT_HIGHER, 599 upper_32_bits(mhi_cntrl->iova_stop), 600 }, 601 { 602 MHICTRLLIMIT_LOWER, 603 lower_32_bits(mhi_cntrl->iova_stop), 604 }, 605 { 606 MHIDATALIMIT_HIGHER, 607 upper_32_bits(mhi_cntrl->iova_stop), 608 }, 609 { 610 MHIDATALIMIT_LOWER, 611 lower_32_bits(mhi_cntrl->iova_stop), 612 }, 613 {0, 0} 614 }; 615 616 dev_dbg(dev, "Initializing MHI registers\n"); 617 618 /* Read channel db offset */ 619 ret = mhi_get_channel_doorbell_offset(mhi_cntrl, &val); 620 if (ret) 621 return ret; 622 623 if (val >= mhi_cntrl->reg_len - (8 * MHI_DEV_WAKE_DB)) { 624 dev_err(dev, "CHDB offset: 0x%x is out of range: 0x%zx\n", 625 val, mhi_cntrl->reg_len - (8 * MHI_DEV_WAKE_DB)); 626 return -ERANGE; 627 } 628 629 /* Setup wake db */ 630 mhi_cntrl->wake_db = base + val + (8 * MHI_DEV_WAKE_DB); 631 mhi_cntrl->wake_set = false; 632 633 /* Setup channel db address for each channel in tre_ring */ 634 mhi_chan = mhi_cntrl->mhi_chan; 635 for (i = 0; i < mhi_cntrl->max_chan; i++, val += 8, mhi_chan++) 636 mhi_chan->tre_ring.db_addr = base + val; 637 638 /* Read event ring db offset */ 639 ret = mhi_read_reg(mhi_cntrl, base, ERDBOFF, &val); 640 if (ret) { 641 dev_err(dev, "Unable to read ERDBOFF register\n"); 642 return -EIO; 643 } 644 645 if (val >= mhi_cntrl->reg_len - (8 * mhi_cntrl->total_ev_rings)) { 646 dev_err(dev, "ERDB offset: 0x%x is out of range: 0x%zx\n", 647 val, mhi_cntrl->reg_len - (8 * mhi_cntrl->total_ev_rings)); 648 return -ERANGE; 649 } 650 651 /* Setup event db address for each ev_ring */ 652 mhi_event = mhi_cntrl->mhi_event; 653 for (i = 0; i < mhi_cntrl->total_ev_rings; i++, val += 8, mhi_event++) { 654 if (mhi_event->offload_ev) 655 continue; 656 657 mhi_event->ring.db_addr = base + val; 658 } 659 660 /* Setup DB register for primary CMD rings */ 661 mhi_cntrl->mhi_cmd[PRIMARY_CMD_RING].ring.db_addr = base + CRDB_LOWER; 662 663 /* Write to MMIO registers */ 664 for (i = 0; reg_info[i].offset; i++) 665 mhi_write_reg(mhi_cntrl, base, reg_info[i].offset, 666 reg_info[i].val); 667 668 ret = mhi_write_reg_field(mhi_cntrl, base, MHICFG, MHICFG_NER_MASK, 669 mhi_cntrl->total_ev_rings); 670 if (ret) { 671 dev_err(dev, "Unable to write MHICFG register\n"); 672 return ret; 673 } 674 675 ret = mhi_write_reg_field(mhi_cntrl, base, MHICFG, MHICFG_NHWER_MASK, 676 mhi_cntrl->hw_ev_rings); 677 if (ret) { 678 dev_err(dev, "Unable to write MHICFG register\n"); 679 return ret; 680 } 681 > 682 if (mhi_cntrl->get_misc_doorbell) 683 doorbell = mhi_cntrl->get_misc_doorbell(mhi_cntrl, MHI_ER_BW_SCALE); 684 685 if (doorbell > 0) { 686 ret = mhi_init_bw_scale(mhi_cntrl, doorbell); 687 if (!ret) 688 mhi_cntrl->bw_scale_db = base + val + (8 * doorbell); 689 else 690 dev_warn(dev, "BW scale setup failure\n"); 691 } 692 return 0; 693 } 694
On 2/17/2025 2:47 PM, Ilpo Järvinen wrote: > On Mon, 17 Feb 2025, Krishna Chaitanya Chundru wrote: > >> As per MHI spec sec 14, MHI supports bandwidth scaling to reduce power >> consumption. MHI bandwidth scaling is advertised in devices that contain >> the bandwidth scaling capability registers. If enabled, the device >> aggregates bandwidth requirements and sends them to the host in the form >> of an event. After the host performs the bandwidth switch, it sends an >> acknowledgment by ringing a doorbell. >> >> if the host supports bandwidth scaling events, then it must set >> BW_CFG.ENABLED bit, set BW_CFG.DB_CHAN_ID to the channel ID to the >> doorbell that will be used by the host to communicate the bandwidth >> scaling status and BW_CFG.ER_INDEX to the index for the event ring >> to which the device should send bandwidth scaling request in the >> bandwidth scaling capability register. >> >> As part of mmio init check if the bw scale capability is present or not, >> if present advertise host supports bw scale by setting all the required >> fields. >> >> MHI layer will only forward the bw scaling request to the controller >> driver, it is responsibility of the controller driver to do actual bw >> scaling and then pass status to the MHI. MHI will response back to the >> device based up on the status of the bw scale received. >> >> Add a new get_misc_doorbell() to get doorbell for misc capabilities to >> use the doorbell with mhi events like MHI BW scale etc. >> >> Use workqueue & mutex for the bw scale events as the pci_set_target_speed() >> which will called by the mhi controller driver can sleep. >> >> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com> >> --- >> drivers/bus/mhi/common.h | 14 ++++++ >> drivers/bus/mhi/host/init.c | 64 ++++++++++++++++++++++++- >> drivers/bus/mhi/host/internal.h | 7 ++- >> drivers/bus/mhi/host/main.c | 102 +++++++++++++++++++++++++++++++++++++++- >> drivers/bus/mhi/host/pm.c | 10 +++- >> include/linux/mhi.h | 13 +++++ >> 6 files changed, 204 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/bus/mhi/common.h b/drivers/bus/mhi/common.h >> index eedac801b800..b900199fab10 100644 >> --- a/drivers/bus/mhi/common.h >> +++ b/drivers/bus/mhi/common.h >> @@ -208,6 +208,20 @@ >> #define MHI_RSCTRE_DATA_DWORD1 cpu_to_le32(FIELD_PREP(GENMASK(23, 16), \ >> MHI_PKT_TYPE_COALESCING)) >> >> +/* MHI Bandwidth scaling offsets */ >> +#define BW_SCALE_CFG_OFFSET (0x04) >> +#define BW_SCALE_CFG_CHAN_DB_ID_SHIFT (25) >> +#define BW_SCALE_CFG_ENABLED_MASK BIT(24) >> +#define BW_SCALE_CFG_ENABLED_SHIFT (24) >> +#define BW_SCALE_CFG_ER_ID_SHIFT (19) >> + >> +#define BW_SCALE_CAP_ID (3) >> +#define MHI_TRE_GET_EV_BW_REQ_SEQ(tre) (((tre)->dword[0] >> 8) & 0xFF) > > This looks open-coded FIELD_GET(). Add the field define and use > FIELD_GET() with it. > ack >> + >> +#define MHI_BW_SCALE_RESULT(status, seq) (((status) & 0xF) << 8 | \ >> + ((seq) & 0xFF)) > > 2x FIELD_PREP(). > ack >> +#define MHI_BW_SCALE_NACK 0xF >> + >> enum mhi_pkt_type { >> MHI_PKT_TYPE_INVALID = 0x0, >> MHI_PKT_TYPE_NOOP_CMD = 0x1, >> diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c >> index 0b14b665ed15..f15c79f85d13 100644 >> --- a/drivers/bus/mhi/host/init.c >> +++ b/drivers/bus/mhi/host/init.c >> @@ -496,10 +496,56 @@ static int mhi_get_capability_offset(struct mhi_controller *mhi_cntrl, u32 capab >> return -ENXIO; >> } >> >> +/* to be used only if a single event ring with the type is present */ >> +static int mhi_get_er_index(struct mhi_controller *mhi_cntrl, >> + enum mhi_er_data_type type) >> +{ >> + struct mhi_event *mhi_event = mhi_cntrl->mhi_event; >> + int i; >> + >> + /* find event ring for requested type */ >> + for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) { >> + if (mhi_event->data_type == type) >> + return mhi_event->er_index; >> + } >> + >> + return -ENOENT; >> +} >> + >> +static int mhi_init_bw_scale(struct mhi_controller *mhi_cntrl, >> + int bw_scale_db) >> +{ >> + struct device *dev = &mhi_cntrl->mhi_dev->dev; >> + u32 bw_cfg_offset, val = 0; >> + int ret, er_index; >> + >> + ret = mhi_get_capability_offset(mhi_cntrl, BW_SCALE_CAP_ID, >> + &bw_cfg_offset); >> + if (ret) >> + return ret; >> + >> + /* No ER configured to support BW scale */ >> + er_index = mhi_get_er_index(mhi_cntrl, MHI_ER_BW_SCALE); >> + if (er_index < 0) >> + return er_index; >> + >> + bw_cfg_offset += BW_SCALE_CFG_OFFSET; >> + >> + /* advertise host support */ >> + val = ((bw_scale_db << BW_SCALE_CFG_CHAN_DB_ID_SHIFT) | >> + BW_SCALE_CFG_ENABLED_MASK | (er_index << BW_SCALE_CFG_ER_ID_SHIFT)); > > Please name the fields with defines and use FIELD_PREP(). And remove > _SHIFT ending defines. > > Also make the file does correct #include for FIELD_PREP/GET if not yet > there. > ack >> + mhi_write_reg(mhi_cntrl, mhi_cntrl->regs, bw_cfg_offset, val); >> + >> + dev_info(dev, "Bandwidth scaling setup complete. Event ring:%d\n", >> + er_index); > > This sound like dev_dbg() to me. What's the value for user in normal > scenarios? > ack >> + return 0; >> +} >> + >> int mhi_init_mmio(struct mhi_controller *mhi_cntrl) >> { >> u32 val; >> - int i, ret; >> + int i, ret, doorbell; >> struct mhi_chan *mhi_chan; >> struct mhi_event *mhi_event; >> void __iomem *base = mhi_cntrl->regs; >> @@ -633,6 +679,16 @@ int mhi_init_mmio(struct mhi_controller *mhi_cntrl) >> return ret; >> } >> >> + if (mhi_cntrl->get_misc_doorbell) >> + doorbell = mhi_cntrl->get_misc_doorbell(mhi_cntrl, MHI_ER_BW_SCALE); >> + >> + if (doorbell > 0) { >> + ret = mhi_init_bw_scale(mhi_cntrl, doorbell); >> + if (!ret) >> + mhi_cntrl->bw_scale_db = base + val + (8 * doorbell); >> + else >> + dev_warn(dev, "BW scale setup failure\n"); > > Is it okay to return 0 in this case? > Not all the controllers support this feature, so we want to return failure so that controllers can continue normally. >> + } >> return 0; >> } >> >> @@ -778,6 +834,9 @@ static int parse_ev_cfg(struct mhi_controller *mhi_cntrl, >> case MHI_ER_CTRL: >> mhi_event->process_event = mhi_process_ctrl_ev_ring; >> break; >> + case MHI_ER_BW_SCALE: >> + mhi_event->process_event = mhi_process_bw_scale_ev_ring; >> + break; >> default: >> dev_err(dev, "Event Ring type not supported\n"); >> goto error_ev_cfg; >> @@ -1012,9 +1071,12 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl, >> >> mhi_event->mhi_cntrl = mhi_cntrl; >> spin_lock_init(&mhi_event->lock); >> + mutex_init(&mhi_event->mutex); >> if (mhi_event->data_type == MHI_ER_CTRL) >> tasklet_init(&mhi_event->task, mhi_ctrl_ev_task, >> (ulong)mhi_event); >> + else if (mhi_event->data_type == MHI_ER_BW_SCALE) >> + INIT_WORK(&mhi_event->work, mhi_process_ev_work); >> else >> tasklet_init(&mhi_event->task, mhi_ev_task, >> (ulong)mhi_event); >> diff --git a/drivers/bus/mhi/host/internal.h b/drivers/bus/mhi/host/internal.h >> index 3134f111be35..bf7c6a7c9383 100644 >> --- a/drivers/bus/mhi/host/internal.h >> +++ b/drivers/bus/mhi/host/internal.h >> @@ -241,6 +241,8 @@ struct mhi_event { >> struct mhi_ring ring; >> struct db_cfg db_cfg; >> struct tasklet_struct task; >> + struct work_struct work; >> + struct mutex mutex; >> spinlock_t lock; >> int (*process_event)(struct mhi_controller *mhi_cntrl, >> struct mhi_event *mhi_event, >> @@ -403,7 +405,8 @@ int mhi_process_data_event_ring(struct mhi_controller *mhi_cntrl, >> struct mhi_event *mhi_event, u32 event_quota); >> int mhi_process_ctrl_ev_ring(struct mhi_controller *mhi_cntrl, >> struct mhi_event *mhi_event, u32 event_quota); >> - >> +int mhi_process_bw_scale_ev_ring(struct mhi_controller *mhi_cntrl, >> + struct mhi_event *mhi_event, u32 event_quota); >> /* ISR handlers */ >> irqreturn_t mhi_irq_handler(int irq_number, void *dev); >> irqreturn_t mhi_intvec_threaded_handler(int irq_number, void *dev); >> @@ -419,5 +422,5 @@ void mhi_unmap_single_no_bb(struct mhi_controller *mhi_cntrl, >> struct mhi_buf_info *buf_info); >> void mhi_unmap_single_use_bb(struct mhi_controller *mhi_cntrl, >> struct mhi_buf_info *buf_info); >> - >> +void mhi_process_ev_work(struct work_struct *work); >> #endif /* _MHI_INT_H */ >> diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c >> index 4de75674f193..a6732bbead44 100644 >> --- a/drivers/bus/mhi/host/main.c >> +++ b/drivers/bus/mhi/host/main.c >> @@ -472,7 +472,10 @@ irqreturn_t mhi_irq_handler(int irq_number, void *dev) >> if (mhi_dev) >> mhi_notify(mhi_dev, MHI_CB_PENDING_DATA); >> } else { >> - tasklet_schedule(&mhi_event->task); >> + if (mhi_event->data_type == MHI_ER_BW_SCALE) >> + queue_work(mhi_cntrl->hiprio_wq, &mhi_event->work); >> + else >> + tasklet_schedule(&mhi_event->task); >> } >> >> return IRQ_HANDLED; >> @@ -1049,6 +1052,103 @@ int mhi_process_data_event_ring(struct mhi_controller *mhi_cntrl, >> return count; >> } >> >> +/* dedicated bw scale event ring processing */ >> +int mhi_process_bw_scale_ev_ring(struct mhi_controller *mhi_cntrl, >> + struct mhi_event *mhi_event, u32 event_quota) >> +{ >> + struct mhi_event_ctxt *er_ctxt = &mhi_cntrl->mhi_ctxt->er_ctxt[mhi_event->er_index]; >> + struct device *dev = &mhi_cntrl->mhi_dev->dev; >> + struct mhi_ring *ev_ring = &mhi_event->ring; >> + dma_addr_t ptr = le64_to_cpu(er_ctxt->rp); >> + u32 response = MHI_BW_SCALE_NACK; >> + struct mhi_ring_element *dev_rp; >> + struct mhi_link_info link_info; >> + int ret = -EINVAL; >> + >> + if (unlikely(MHI_EVENT_ACCESS_INVALID(mhi_cntrl->pm_state))) { >> + ret = -EIO; >> + goto exit_bw_scale_process; >> + } >> + >> + if (!MHI_IN_MISSION_MODE(mhi_cntrl->ee)) >> + goto exit_bw_scale_process; >> + >> + if (!is_valid_ring_ptr(ev_ring, ptr)) { >> + dev_err(dev, >> + "Event ring rp points outside of the event ring\n"); >> + ret = -EIO; >> + goto exit_bw_scale_process; >> + } >> + >> + dev_rp = mhi_to_virtual(ev_ring, ptr); >> + >> + /* if rp points to base, we need to wrap it around */ >> + if (dev_rp == ev_ring->base) >> + dev_rp = ev_ring->base + ev_ring->len; >> + dev_rp--; >> + >> + /* fast forward to currently processed element and recycle er */ >> + ev_ring->rp = dev_rp; >> + ev_ring->wp = dev_rp - 1; >> + if (ev_ring->wp < ev_ring->base) >> + ev_ring->wp = ev_ring->base + ev_ring->len - ev_ring->el_size; >> + mhi_recycle_ev_ring_element(mhi_cntrl, ev_ring); >> + >> + if (WARN_ON(MHI_TRE_GET_EV_TYPE(dev_rp) != MHI_PKT_TYPE_BW_REQ_EVENT)) { >> + dev_err(dev, "!BW SCALE REQ event\n"); >> + goto exit_bw_scale_process; >> + } >> + >> + link_info.target_link_speed = MHI_TRE_GET_EV_LINKSPEED(dev_rp); >> + link_info.target_link_width = MHI_TRE_GET_EV_LINKWIDTH(dev_rp); >> + link_info.sequence_num = MHI_TRE_GET_EV_BW_REQ_SEQ(dev_rp); >> + >> + dev_info(dev, "Received BW_REQ with seq:%d link speed:0x%x width:0x%x\n", >> + link_info.sequence_num, >> + link_info.target_link_speed, >> + link_info.target_link_width); >> + >> + /* bring host and device out of suspended states */ >> + ret = mhi_device_get_sync(mhi_cntrl->mhi_dev); >> + if (ret) >> + goto exit_bw_scale_process; >> + >> + mhi_cntrl->runtime_get(mhi_cntrl); >> + >> + ret = mhi_cntrl->bw_scale(mhi_cntrl, &link_info); >> + if (!ret) >> + response = 0; >> + >> + response = MHI_BW_SCALE_RESULT(response, link_info.sequence_num); >> + >> + write_lock_bh(&mhi_cntrl->pm_lock); >> + mhi_write_reg(mhi_cntrl, mhi_cntrl->bw_scale_db, 0, response); >> + write_unlock_bh(&mhi_cntrl->pm_lock); >> + >> + mhi_cntrl->runtime_put(mhi_cntrl); >> + mhi_device_put(mhi_cntrl->mhi_dev); >> + >> +exit_bw_scale_process: >> + dev_info(dev, "exit er_index:%u ret:%d\n", mhi_event->er_index, ret); > > There's zero value for normal user with something as obscure as > this, make it dev_dbg(). > ack >> + return ret; >> +} >> + >> +void mhi_process_ev_work(struct work_struct *work) >> +{ >> + struct mhi_event *mhi_event = container_of(work, struct mhi_event, >> + work); >> + >> + struct mhi_controller *mhi_cntrl = mhi_event->mhi_cntrl; >> + >> + if (unlikely(MHI_EVENT_ACCESS_INVALID(mhi_cntrl->pm_state))) >> + return; >> + >> + mutex_lock(&mhi_event->mutex); > > guard()() > ack. - Krishna Chaitanya. >> + mhi_event->process_event(mhi_cntrl, mhi_event, U32_MAX); >> + mutex_unlock(&mhi_event->mutex); >> +} >> + >> void mhi_ev_task(unsigned long data) >> { >> struct mhi_event *mhi_event = (struct mhi_event *)data; >> diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c >> index 11c0e751f223..9c848ca582f0 100644 >> --- a/drivers/bus/mhi/host/pm.c >> +++ b/drivers/bus/mhi/host/pm.c >> @@ -523,7 +523,10 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl, >> if (mhi_event->offload_ev) >> continue; >> disable_irq(mhi_cntrl->irq[mhi_event->irq]); >> - tasklet_kill(&mhi_event->task); >> + if (mhi_event->data_type == MHI_ER_BW_SCALE) >> + cancel_work_sync(&mhi_event->work); >> + else >> + tasklet_kill(&mhi_event->task); >> } >> >> /* Release lock and wait for all pending threads to complete */ >> @@ -670,7 +673,10 @@ static void mhi_pm_sys_error_transition(struct mhi_controller *mhi_cntrl) >> for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) { >> if (mhi_event->offload_ev) >> continue; >> - tasklet_kill(&mhi_event->task); >> + if (mhi_event->data_type == MHI_ER_BW_SCALE) >> + cancel_work_sync(&mhi_event->work); >> + else >> + tasklet_kill(&mhi_event->task); >> } >> >> /* Release lock and wait for all pending threads to complete */ >> diff --git a/include/linux/mhi.h b/include/linux/mhi.h >> index 059dc94d20bb..d9bf88c35d14 100644 >> --- a/include/linux/mhi.h >> +++ b/include/linux/mhi.h >> @@ -102,10 +102,12 @@ struct image_info { >> * struct mhi_link_info - BW requirement >> * target_link_speed - Link speed as defined by TLS bits in LinkControl reg >> * target_link_width - Link width as defined by NLW bits in LinkStatus reg >> + * sequence_num - used by device to track bw requests sent to host >> */ >> struct mhi_link_info { >> unsigned int target_link_speed; >> unsigned int target_link_width; >> + int sequence_num; >> }; >> >> /** >> @@ -183,10 +185,12 @@ enum mhi_ch_ee_mask { >> * enum mhi_er_data_type - Event ring data types >> * @MHI_ER_DATA: Only client data over this ring >> * @MHI_ER_CTRL: MHI control data and client data >> + * @MHI_ER_BW_SCALE: MHI controller bandwidth scale functionality >> */ >> enum mhi_er_data_type { >> MHI_ER_DATA, >> MHI_ER_CTRL, >> + MHI_ER_BW_SCALE, >> }; >> >> /** >> @@ -299,6 +303,7 @@ struct mhi_controller_config { >> * @bhi: Points to base of MHI BHI register space >> * @bhie: Points to base of MHI BHIe register space >> * @wake_db: MHI WAKE doorbell register address >> + * @wake_db: MHI BW_SCALE doorbell register address >> * @iova_start: IOMMU starting address for data (required) >> * @iova_stop: IOMMU stop address for data (required) >> * @fw_image: Firmware image name for normal booting (optional) >> @@ -355,6 +360,8 @@ struct mhi_controller_config { >> * @write_reg: Write a MHI register via the physical link (required) >> * @reset: Controller specific reset function (optional) >> * @edl_trigger: CB function to trigger EDL mode (optional) >> + * @get_misc_doobell: function to get doorbell used for MISC feature like BW scale etc (optional) >> + * @bw_scale: CB function for passing BW scale info (optional) >> * @buffer_len: Bounce buffer length >> * @index: Index of the MHI controller instance >> * @bounce_buf: Use of bounce buffer >> @@ -376,6 +383,7 @@ struct mhi_controller { >> void __iomem *bhi; >> void __iomem *bhie; >> void __iomem *wake_db; >> + void __iomem *bw_scale_db; >> >> dma_addr_t iova_start; >> dma_addr_t iova_stop; >> @@ -440,6 +448,11 @@ struct mhi_controller { >> void (*reset)(struct mhi_controller *mhi_cntrl); >> int (*edl_trigger)(struct mhi_controller *mhi_cntrl); >> >> + int (*get_misc_doorbell)(struct mhi_controller *mhi_cntrl, >> + enum mhi_er_data_type type); >> + int (*bw_scale)(struct mhi_controller *mhi_cntrl, >> + struct mhi_link_info *link_info); >> + >> size_t buffer_len; >> int index; >> bool bounce_buf; >> >> >
diff --git a/drivers/bus/mhi/common.h b/drivers/bus/mhi/common.h index eedac801b800..b900199fab10 100644 --- a/drivers/bus/mhi/common.h +++ b/drivers/bus/mhi/common.h @@ -208,6 +208,20 @@ #define MHI_RSCTRE_DATA_DWORD1 cpu_to_le32(FIELD_PREP(GENMASK(23, 16), \ MHI_PKT_TYPE_COALESCING)) +/* MHI Bandwidth scaling offsets */ +#define BW_SCALE_CFG_OFFSET (0x04) +#define BW_SCALE_CFG_CHAN_DB_ID_SHIFT (25) +#define BW_SCALE_CFG_ENABLED_MASK BIT(24) +#define BW_SCALE_CFG_ENABLED_SHIFT (24) +#define BW_SCALE_CFG_ER_ID_SHIFT (19) + +#define BW_SCALE_CAP_ID (3) +#define MHI_TRE_GET_EV_BW_REQ_SEQ(tre) (((tre)->dword[0] >> 8) & 0xFF) + +#define MHI_BW_SCALE_RESULT(status, seq) (((status) & 0xF) << 8 | \ + ((seq) & 0xFF)) +#define MHI_BW_SCALE_NACK 0xF + enum mhi_pkt_type { MHI_PKT_TYPE_INVALID = 0x0, MHI_PKT_TYPE_NOOP_CMD = 0x1, diff --git a/drivers/bus/mhi/host/init.c b/drivers/bus/mhi/host/init.c index 0b14b665ed15..f15c79f85d13 100644 --- a/drivers/bus/mhi/host/init.c +++ b/drivers/bus/mhi/host/init.c @@ -496,10 +496,56 @@ static int mhi_get_capability_offset(struct mhi_controller *mhi_cntrl, u32 capab return -ENXIO; } +/* to be used only if a single event ring with the type is present */ +static int mhi_get_er_index(struct mhi_controller *mhi_cntrl, + enum mhi_er_data_type type) +{ + struct mhi_event *mhi_event = mhi_cntrl->mhi_event; + int i; + + /* find event ring for requested type */ + for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) { + if (mhi_event->data_type == type) + return mhi_event->er_index; + } + + return -ENOENT; +} + +static int mhi_init_bw_scale(struct mhi_controller *mhi_cntrl, + int bw_scale_db) +{ + struct device *dev = &mhi_cntrl->mhi_dev->dev; + u32 bw_cfg_offset, val = 0; + int ret, er_index; + + ret = mhi_get_capability_offset(mhi_cntrl, BW_SCALE_CAP_ID, + &bw_cfg_offset); + if (ret) + return ret; + + /* No ER configured to support BW scale */ + er_index = mhi_get_er_index(mhi_cntrl, MHI_ER_BW_SCALE); + if (er_index < 0) + return er_index; + + bw_cfg_offset += BW_SCALE_CFG_OFFSET; + + /* advertise host support */ + val = ((bw_scale_db << BW_SCALE_CFG_CHAN_DB_ID_SHIFT) | + BW_SCALE_CFG_ENABLED_MASK | (er_index << BW_SCALE_CFG_ER_ID_SHIFT)); + mhi_write_reg(mhi_cntrl, mhi_cntrl->regs, bw_cfg_offset, val); + + dev_info(dev, "Bandwidth scaling setup complete. Event ring:%d\n", + er_index); + + return 0; +} + int mhi_init_mmio(struct mhi_controller *mhi_cntrl) { u32 val; - int i, ret; + int i, ret, doorbell; struct mhi_chan *mhi_chan; struct mhi_event *mhi_event; void __iomem *base = mhi_cntrl->regs; @@ -633,6 +679,16 @@ int mhi_init_mmio(struct mhi_controller *mhi_cntrl) return ret; } + if (mhi_cntrl->get_misc_doorbell) + doorbell = mhi_cntrl->get_misc_doorbell(mhi_cntrl, MHI_ER_BW_SCALE); + + if (doorbell > 0) { + ret = mhi_init_bw_scale(mhi_cntrl, doorbell); + if (!ret) + mhi_cntrl->bw_scale_db = base + val + (8 * doorbell); + else + dev_warn(dev, "BW scale setup failure\n"); + } return 0; } @@ -778,6 +834,9 @@ static int parse_ev_cfg(struct mhi_controller *mhi_cntrl, case MHI_ER_CTRL: mhi_event->process_event = mhi_process_ctrl_ev_ring; break; + case MHI_ER_BW_SCALE: + mhi_event->process_event = mhi_process_bw_scale_ev_ring; + break; default: dev_err(dev, "Event Ring type not supported\n"); goto error_ev_cfg; @@ -1012,9 +1071,12 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl, mhi_event->mhi_cntrl = mhi_cntrl; spin_lock_init(&mhi_event->lock); + mutex_init(&mhi_event->mutex); if (mhi_event->data_type == MHI_ER_CTRL) tasklet_init(&mhi_event->task, mhi_ctrl_ev_task, (ulong)mhi_event); + else if (mhi_event->data_type == MHI_ER_BW_SCALE) + INIT_WORK(&mhi_event->work, mhi_process_ev_work); else tasklet_init(&mhi_event->task, mhi_ev_task, (ulong)mhi_event); diff --git a/drivers/bus/mhi/host/internal.h b/drivers/bus/mhi/host/internal.h index 3134f111be35..bf7c6a7c9383 100644 --- a/drivers/bus/mhi/host/internal.h +++ b/drivers/bus/mhi/host/internal.h @@ -241,6 +241,8 @@ struct mhi_event { struct mhi_ring ring; struct db_cfg db_cfg; struct tasklet_struct task; + struct work_struct work; + struct mutex mutex; spinlock_t lock; int (*process_event)(struct mhi_controller *mhi_cntrl, struct mhi_event *mhi_event, @@ -403,7 +405,8 @@ int mhi_process_data_event_ring(struct mhi_controller *mhi_cntrl, struct mhi_event *mhi_event, u32 event_quota); int mhi_process_ctrl_ev_ring(struct mhi_controller *mhi_cntrl, struct mhi_event *mhi_event, u32 event_quota); - +int mhi_process_bw_scale_ev_ring(struct mhi_controller *mhi_cntrl, + struct mhi_event *mhi_event, u32 event_quota); /* ISR handlers */ irqreturn_t mhi_irq_handler(int irq_number, void *dev); irqreturn_t mhi_intvec_threaded_handler(int irq_number, void *dev); @@ -419,5 +422,5 @@ void mhi_unmap_single_no_bb(struct mhi_controller *mhi_cntrl, struct mhi_buf_info *buf_info); void mhi_unmap_single_use_bb(struct mhi_controller *mhi_cntrl, struct mhi_buf_info *buf_info); - +void mhi_process_ev_work(struct work_struct *work); #endif /* _MHI_INT_H */ diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c index 4de75674f193..a6732bbead44 100644 --- a/drivers/bus/mhi/host/main.c +++ b/drivers/bus/mhi/host/main.c @@ -472,7 +472,10 @@ irqreturn_t mhi_irq_handler(int irq_number, void *dev) if (mhi_dev) mhi_notify(mhi_dev, MHI_CB_PENDING_DATA); } else { - tasklet_schedule(&mhi_event->task); + if (mhi_event->data_type == MHI_ER_BW_SCALE) + queue_work(mhi_cntrl->hiprio_wq, &mhi_event->work); + else + tasklet_schedule(&mhi_event->task); } return IRQ_HANDLED; @@ -1049,6 +1052,103 @@ int mhi_process_data_event_ring(struct mhi_controller *mhi_cntrl, return count; } +/* dedicated bw scale event ring processing */ +int mhi_process_bw_scale_ev_ring(struct mhi_controller *mhi_cntrl, + struct mhi_event *mhi_event, u32 event_quota) +{ + struct mhi_event_ctxt *er_ctxt = &mhi_cntrl->mhi_ctxt->er_ctxt[mhi_event->er_index]; + struct device *dev = &mhi_cntrl->mhi_dev->dev; + struct mhi_ring *ev_ring = &mhi_event->ring; + dma_addr_t ptr = le64_to_cpu(er_ctxt->rp); + u32 response = MHI_BW_SCALE_NACK; + struct mhi_ring_element *dev_rp; + struct mhi_link_info link_info; + int ret = -EINVAL; + + if (unlikely(MHI_EVENT_ACCESS_INVALID(mhi_cntrl->pm_state))) { + ret = -EIO; + goto exit_bw_scale_process; + } + + if (!MHI_IN_MISSION_MODE(mhi_cntrl->ee)) + goto exit_bw_scale_process; + + if (!is_valid_ring_ptr(ev_ring, ptr)) { + dev_err(dev, + "Event ring rp points outside of the event ring\n"); + ret = -EIO; + goto exit_bw_scale_process; + } + + dev_rp = mhi_to_virtual(ev_ring, ptr); + + /* if rp points to base, we need to wrap it around */ + if (dev_rp == ev_ring->base) + dev_rp = ev_ring->base + ev_ring->len; + dev_rp--; + + /* fast forward to currently processed element and recycle er */ + ev_ring->rp = dev_rp; + ev_ring->wp = dev_rp - 1; + if (ev_ring->wp < ev_ring->base) + ev_ring->wp = ev_ring->base + ev_ring->len - ev_ring->el_size; + mhi_recycle_ev_ring_element(mhi_cntrl, ev_ring); + + if (WARN_ON(MHI_TRE_GET_EV_TYPE(dev_rp) != MHI_PKT_TYPE_BW_REQ_EVENT)) { + dev_err(dev, "!BW SCALE REQ event\n"); + goto exit_bw_scale_process; + } + + link_info.target_link_speed = MHI_TRE_GET_EV_LINKSPEED(dev_rp); + link_info.target_link_width = MHI_TRE_GET_EV_LINKWIDTH(dev_rp); + link_info.sequence_num = MHI_TRE_GET_EV_BW_REQ_SEQ(dev_rp); + + dev_info(dev, "Received BW_REQ with seq:%d link speed:0x%x width:0x%x\n", + link_info.sequence_num, + link_info.target_link_speed, + link_info.target_link_width); + + /* bring host and device out of suspended states */ + ret = mhi_device_get_sync(mhi_cntrl->mhi_dev); + if (ret) + goto exit_bw_scale_process; + + mhi_cntrl->runtime_get(mhi_cntrl); + + ret = mhi_cntrl->bw_scale(mhi_cntrl, &link_info); + if (!ret) + response = 0; + + response = MHI_BW_SCALE_RESULT(response, link_info.sequence_num); + + write_lock_bh(&mhi_cntrl->pm_lock); + mhi_write_reg(mhi_cntrl, mhi_cntrl->bw_scale_db, 0, response); + write_unlock_bh(&mhi_cntrl->pm_lock); + + mhi_cntrl->runtime_put(mhi_cntrl); + mhi_device_put(mhi_cntrl->mhi_dev); + +exit_bw_scale_process: + dev_info(dev, "exit er_index:%u ret:%d\n", mhi_event->er_index, ret); + + return ret; +} + +void mhi_process_ev_work(struct work_struct *work) +{ + struct mhi_event *mhi_event = container_of(work, struct mhi_event, + work); + + struct mhi_controller *mhi_cntrl = mhi_event->mhi_cntrl; + + if (unlikely(MHI_EVENT_ACCESS_INVALID(mhi_cntrl->pm_state))) + return; + + mutex_lock(&mhi_event->mutex); + mhi_event->process_event(mhi_cntrl, mhi_event, U32_MAX); + mutex_unlock(&mhi_event->mutex); +} + void mhi_ev_task(unsigned long data) { struct mhi_event *mhi_event = (struct mhi_event *)data; diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c index 11c0e751f223..9c848ca582f0 100644 --- a/drivers/bus/mhi/host/pm.c +++ b/drivers/bus/mhi/host/pm.c @@ -523,7 +523,10 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl, if (mhi_event->offload_ev) continue; disable_irq(mhi_cntrl->irq[mhi_event->irq]); - tasklet_kill(&mhi_event->task); + if (mhi_event->data_type == MHI_ER_BW_SCALE) + cancel_work_sync(&mhi_event->work); + else + tasklet_kill(&mhi_event->task); } /* Release lock and wait for all pending threads to complete */ @@ -670,7 +673,10 @@ static void mhi_pm_sys_error_transition(struct mhi_controller *mhi_cntrl) for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) { if (mhi_event->offload_ev) continue; - tasklet_kill(&mhi_event->task); + if (mhi_event->data_type == MHI_ER_BW_SCALE) + cancel_work_sync(&mhi_event->work); + else + tasklet_kill(&mhi_event->task); } /* Release lock and wait for all pending threads to complete */ diff --git a/include/linux/mhi.h b/include/linux/mhi.h index 059dc94d20bb..d9bf88c35d14 100644 --- a/include/linux/mhi.h +++ b/include/linux/mhi.h @@ -102,10 +102,12 @@ struct image_info { * struct mhi_link_info - BW requirement * target_link_speed - Link speed as defined by TLS bits in LinkControl reg * target_link_width - Link width as defined by NLW bits in LinkStatus reg + * sequence_num - used by device to track bw requests sent to host */ struct mhi_link_info { unsigned int target_link_speed; unsigned int target_link_width; + int sequence_num; }; /** @@ -183,10 +185,12 @@ enum mhi_ch_ee_mask { * enum mhi_er_data_type - Event ring data types * @MHI_ER_DATA: Only client data over this ring * @MHI_ER_CTRL: MHI control data and client data + * @MHI_ER_BW_SCALE: MHI controller bandwidth scale functionality */ enum mhi_er_data_type { MHI_ER_DATA, MHI_ER_CTRL, + MHI_ER_BW_SCALE, }; /** @@ -299,6 +303,7 @@ struct mhi_controller_config { * @bhi: Points to base of MHI BHI register space * @bhie: Points to base of MHI BHIe register space * @wake_db: MHI WAKE doorbell register address + * @wake_db: MHI BW_SCALE doorbell register address * @iova_start: IOMMU starting address for data (required) * @iova_stop: IOMMU stop address for data (required) * @fw_image: Firmware image name for normal booting (optional) @@ -355,6 +360,8 @@ struct mhi_controller_config { * @write_reg: Write a MHI register via the physical link (required) * @reset: Controller specific reset function (optional) * @edl_trigger: CB function to trigger EDL mode (optional) + * @get_misc_doobell: function to get doorbell used for MISC feature like BW scale etc (optional) + * @bw_scale: CB function for passing BW scale info (optional) * @buffer_len: Bounce buffer length * @index: Index of the MHI controller instance * @bounce_buf: Use of bounce buffer @@ -376,6 +383,7 @@ struct mhi_controller { void __iomem *bhi; void __iomem *bhie; void __iomem *wake_db; + void __iomem *bw_scale_db; dma_addr_t iova_start; dma_addr_t iova_stop; @@ -440,6 +448,11 @@ struct mhi_controller { void (*reset)(struct mhi_controller *mhi_cntrl); int (*edl_trigger)(struct mhi_controller *mhi_cntrl); + int (*get_misc_doorbell)(struct mhi_controller *mhi_cntrl, + enum mhi_er_data_type type); + int (*bw_scale)(struct mhi_controller *mhi_cntrl, + struct mhi_link_info *link_info); + size_t buffer_len; int index; bool bounce_buf;
As per MHI spec sec 14, MHI supports bandwidth scaling to reduce power consumption. MHI bandwidth scaling is advertised in devices that contain the bandwidth scaling capability registers. If enabled, the device aggregates bandwidth requirements and sends them to the host in the form of an event. After the host performs the bandwidth switch, it sends an acknowledgment by ringing a doorbell. if the host supports bandwidth scaling events, then it must set BW_CFG.ENABLED bit, set BW_CFG.DB_CHAN_ID to the channel ID to the doorbell that will be used by the host to communicate the bandwidth scaling status and BW_CFG.ER_INDEX to the index for the event ring to which the device should send bandwidth scaling request in the bandwidth scaling capability register. As part of mmio init check if the bw scale capability is present or not, if present advertise host supports bw scale by setting all the required fields. MHI layer will only forward the bw scaling request to the controller driver, it is responsibility of the controller driver to do actual bw scaling and then pass status to the MHI. MHI will response back to the device based up on the status of the bw scale received. Add a new get_misc_doorbell() to get doorbell for misc capabilities to use the doorbell with mhi events like MHI BW scale etc. Use workqueue & mutex for the bw scale events as the pci_set_target_speed() which will called by the mhi controller driver can sleep. Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com> --- drivers/bus/mhi/common.h | 14 ++++++ drivers/bus/mhi/host/init.c | 64 ++++++++++++++++++++++++- drivers/bus/mhi/host/internal.h | 7 ++- drivers/bus/mhi/host/main.c | 102 +++++++++++++++++++++++++++++++++++++++- drivers/bus/mhi/host/pm.c | 10 +++- include/linux/mhi.h | 13 +++++ 6 files changed, 204 insertions(+), 6 deletions(-)