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

[Russell King - ARM Linux]

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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