| Message ID | 1361872613-12040-1-git-send-email-inderpal.singh@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Feb 26, 2013 at 03:26:53PM +0530, Inderpal Singh wrote: > Only cortex-a9 based samsung platforms have l2x0 cache controller. Hence check > the same before restoring the cache in resume. Why is this patch soo complicated? Can't you read the CPUs MIDR register from assembly code?
On 26 February 2013 15:32, Russell King - ARM Linux <linux@arm.linux.org.uk> wrote: > On Tue, Feb 26, 2013 at 03:26:53PM +0530, Inderpal Singh wrote: >> Only cortex-a9 based samsung platforms have l2x0 cache controller. Hence check >> the same before restoring the cache in resume. > > Why is this patch soo complicated? Can't you read the CPUs MIDR register > from assembly code? I wanted to read MIDR only once thats why didn't read in resume function in assembly as the same resume function gets used in cpuidle path. Regards, Inder
On Tue, Feb 26, 2013 at 04:46:01PM +0530, Inderpal Singh wrote: > On 26 February 2013 15:32, Russell King - ARM Linux > <linux@arm.linux.org.uk> wrote: > > On Tue, Feb 26, 2013 at 03:26:53PM +0530, Inderpal Singh wrote: > >> Only cortex-a9 based samsung platforms have l2x0 cache controller. Hence check > >> the same before restoring the cache in resume. > > > > Why is this patch soo complicated? Can't you read the CPUs MIDR register > > from assembly code? > > I wanted to read MIDR only once thats why didn't read in resume > function in assembly as the same resume function gets used in cpuidle > path. It's more expensive to load it from memory than to read it from CP15.
On 26 February 2013 16:52, Russell King - ARM Linux <linux@arm.linux.org.uk> wrote: > On Tue, Feb 26, 2013 at 04:46:01PM +0530, Inderpal Singh wrote: >> On 26 February 2013 15:32, Russell King - ARM Linux >> <linux@arm.linux.org.uk> wrote: >> > On Tue, Feb 26, 2013 at 03:26:53PM +0530, Inderpal Singh wrote: >> >> Only cortex-a9 based samsung platforms have l2x0 cache controller. Hence check >> >> the same before restoring the cache in resume. >> > >> > Why is this patch soo complicated? Can't you read the CPUs MIDR register >> > from assembly code? >> >> I wanted to read MIDR only once thats why didn't read in resume >> function in assembly as the same resume function gets used in cpuidle >> path. > > It's more expensive to load it from memory than to read it from CP15. Ok, I will change it to read from CP15 in assembly and resubmit the patch. Thanks for the review. Regards, Inder
diff --git a/arch/arm/mach-exynos/common.c b/arch/arm/mach-exynos/common.c index c4b2071..5585325 100644 --- a/arch/arm/mach-exynos/common.c +++ b/arch/arm/mach-exynos/common.c @@ -31,6 +31,7 @@ #include <asm/mach/map.h> #include <asm/mach/irq.h> #include <asm/cacheflush.h> +#include <asm/cputype.h> #include <mach/regs-irq.h> #include <mach/regs-pmu.h> @@ -53,6 +54,7 @@ #include "common.h" #define L2_AUX_VAL 0x7C470001 #define L2_AUX_MASK 0xC200ffff +#define CPU_MASK 0xff0ffff0 static const char name_exynos4210[] = "EXYNOS4210"; static const char name_exynos4212[] = "EXYNOS4212"; @@ -716,6 +718,8 @@ static int __init exynos4_l2x0_cache_init(void) if (soc_is_exynos5250() || soc_is_exynos5440()) return 0; + cpu_midr = read_cpuid_id() & CPU_MASK; + ret = l2x0_of_init(L2_AUX_VAL, L2_AUX_MASK); if (!ret) { l2x0_regs_phys = virt_to_phys(&l2x0_saved_regs); diff --git a/arch/arm/plat-samsung/include/plat/pm.h b/arch/arm/plat-samsung/include/plat/pm.h index f6fcade..532f5d7 100644 --- a/arch/arm/plat-samsung/include/plat/pm.h +++ b/arch/arm/plat-samsung/include/plat/pm.h @@ -184,3 +184,4 @@ extern void samsung_pm_save_gpios(void); extern void s3c_pm_save_core(void); extern void s3c_pm_restore_core(void); +extern unsigned long cpu_midr; diff --git a/arch/arm/plat-samsung/s5p-sleep.S b/arch/arm/plat-samsung/s5p-sleep.S index bdf6dad..3b350d0 100644 --- a/arch/arm/plat-samsung/s5p-sleep.S +++ b/arch/arm/plat-samsung/s5p-sleep.S @@ -25,6 +25,8 @@ #include <asm/asm-offsets.h> #include <asm/hardware/cache-l2x0.h> +#define CPU_CORTEX_A9 0x410FC090 + /* * The following code is located into the .data section. This is to * allow l2x0_regs_phys to be accessed with a relative load while we @@ -51,6 +53,11 @@ ENTRY(s3c_cpu_resume) #ifdef CONFIG_CACHE_L2X0 + adr r0, cpu_midr + ldr r1, [r0] + ldr r0, =CPU_CORTEX_A9 + cmp r1, r0 + bne resume_l2on adr r0, l2x0_regs_phys ldr r0, [r0] ldr r1, [r0, #L2X0_R_PHY_BASE] @@ -77,4 +84,7 @@ ENDPROC(s3c_cpu_resume) .globl l2x0_regs_phys l2x0_regs_phys: .long 0 + .globl cpu_midr +cpu_midr: + .long 0 #endif
Only cortex-a9 based samsung platforms have l2x0 cache controller. Hence check the same before restoring the cache in resume. This is needed for single kernel image. Signed-off-by: Inderpal Singh <inderpal.singh@linaro.org> --- changes in v2: - check processor midr instead of checking all soc ids as suggested by Kukjin arch/arm/mach-exynos/common.c | 4 ++++ arch/arm/plat-samsung/include/plat/pm.h | 1 + arch/arm/plat-samsung/s5p-sleep.S | 10 ++++++++++ 3 files changed, 15 insertions(+)