Re: [PATCH 2/6] ARM: pm: add generic CPU suspend/resume support

Russell King - ARM Linux
2011-02-20T12:00:58Z

Kukjin, could you test this update as well please?

Thanks.

On Tue, Feb 15, 2011 at 11:04:53AM +0000, Russell King - ARM Linux wrote:
> On Fri, Feb 11, 2011 at 06:50:57PM -0800, Colin Cross wrote:
> > > +ENDPROC(cpu_resume_turn_mmu_on)
> > > +cpu_resume_after_mmu:
> > > +       str     r5, [r2, r4, lsl #2]    @ restore old mapping
> > > +#ifdef MULTI_CACHE
> > > +       ldr     r10, =cpu_cache
> > > +       ldr     pc, [r10, #CACHE_FLUSH_KERN_ALL]
> > > +#else
> > > +       b       __cpuc_flush_kern_all
> > > +#endif
>
> I think we can eliminate this cache flush by delaying the cache enable
> as below. Could you see whether Tegra 2 survives this please?
> Thanks.
>
> diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S
> index bed1876..193be5f 100644
> --- a/arch/arm/kernel/sleep.S
> +++ b/arch/arm/kernel/sleep.S
> @@ -4,6 +4,7 @@
> #include <asm/assembler.h>
> #include <asm/glue-cache.h>
> #include <asm/glue-proc.h>
> +#include <asm/system.h>
> .text
>
> /*
> @@ -81,25 +82,22 @@ ENTRY(cpu_resume_mmu)
> str r3, [r2, r4, lsl #2] @ setup 1:1 mapping for mmu code
> sub r2, r2, r1
> ldr r3, =cpu_resume_after_mmu
> + bic r1, r0, #CR_C @ ensure D-cache is disabled
> b cpu_resume_turn_mmu_on
> ENDPROC(cpu_resume_mmu)
> .ltorg
> .align 5
> cpu_resume_turn_mmu_on:
> - mcr p15, 0, r0, c1, c0, 0 @ turn on MMU, caches, etc
> - mrc p15, 0, r0, c0, c0, 0 @ read id reg
> - mov r0, r0
> - mov r0, r0
> + mcr p15, 0, r1, c1, c0, 0 @ turn on MMU, I-cache, etc
> + mrc p15, 0, r1, c0, c0, 0 @ read id reg
> + mov r1, r1
> + mov r1, r1
> mov pc, r3 @ jump to virtual address
> ENDPROC(cpu_resume_turn_mmu_on)
> cpu_resume_after_mmu:
> str r5, [r2, r4, lsl #2] @ restore old mapping
> -#ifdef MULTI_CACHE
> - ldr r10, =cpu_cache
> - ldr pc, [r10, #CACHE_FLUSH_KERN_ALL]
> -#else
> - b __cpuc_flush_kern_all
> -#endif
> + mcr p15, 0, r0, c1, c0, 0 @ turn on D-cache
> + mov pc, lr
>
> /*
> * Note: Yes, part of the following code is located into the .data section.
>
>
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