Re: [PATCH] OMAP3: run the ASM sleep code from DDR

[Kevin Hilman <khilman@ti.com>]

Russell King - ARM Linux <linux@arm.linux.org.uk> writes:

> On Wed, Jun 29, 2011 at 10:29:49AM -0700, Kevin Hilman wrote:
>> Russell, if you're OK with it, can you add it to your suspend branch for
>> the upcoming merge window?
>
> Yes - though I think we can go a little bit further - this patch is on
> top of my code so far, and is untested.  There isn't a need for the
> saving of these registers to be in assembly because we can read them
> just as easily from C code.

Indeed

> Comments?

Looks good to me (although untested) care to respin on top of $SUBJECT
patch?  

Minor comments below...

>  arch/arm/mach-omap2/pm.h        |    2 +-
>  arch/arm/mach-omap2/pm34xx.c    |   19 +++++++++++++++++--
>  arch/arm/mach-omap2/sleep34xx.S |   12 ++----------
>  3 files changed, 20 insertions(+), 13 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/pm.h b/arch/arm/mach-omap2/pm.h
> index 45bcfce..4984cca 100644
> --- a/arch/arm/mach-omap2/pm.h
> +++ b/arch/arm/mach-omap2/pm.h
> @@ -92,7 +92,7 @@ extern void omap24xx_idle_loop_suspend(void);
>  
>  extern void omap24xx_cpu_suspend(u32 dll_ctrl, void __iomem *sdrc_dlla_ctrl,
>  					void __iomem *sdrc_power);
> -extern void omap34xx_cpu_suspend(u32 *addr, int save_state);
> +extern void omap34xx_cpu_suspend(int save_state);
>  extern int save_secure_ram_context(u32 *addr);
>  extern void omap3_save_scratchpad_contents(void);
>  
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> index 3e9a13e..6366352 100644
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -78,7 +78,7 @@ struct power_state {
>  
>  static LIST_HEAD(pwrst_list);
>  
> -static void (*_omap_sram_idle)(u32 *addr, int save_state);
> +static void (*_omap_sram_idle)(int save_state);
>  
>  static int (*_omap_save_secure_sram)(u32 *addr);
>  
> @@ -307,9 +307,22 @@ static irqreturn_t prcm_interrupt_handler (int irq, void *dev_id)
>  	return IRQ_HANDLED;
>  }
>  
> +static void omap34xx_save_context(u32 *save)
> +{
> +	u32 val;
> +
> +	asm("mrc p15, 0, %0, c1, c0, 1" : "=r" (val));

Minor: for those of us who don't have all these registers memorized when
looking at the assembly, maybe keeping the original comments (e.g. "Read
AUX 

> +	*save++ = 1;
> +	*save++ = val;
> +
> +	asm("mrc p15, 1, %0, c9, c0, 2" : "=r" (val));
> +	*save++ = 1;
> +	*save++ = val;
> +}
> +
>  static void omap34xx_do_sram_idle(unsigned long save_state)
>  {
> -	_omap_sram_idle(omap3_arm_context, save_state);
> +	_omap_sram_idle(save_state);
>  }
>  
>  void omap_sram_idle(void)
> @@ -412,6 +425,8 @@ void omap_sram_idle(void)
>  	 * get saved. The rest is placed on the stack, and restored
>  	 * from there before resuming.
>  	 */
> +	if (save_state)
> +		omap34xx_save_context(omap3_arm_context);
>  	if (save_state == 1 || save_state == 3)
>  		cpu_suspend(save_state, omap34xx_do_sram_idle);
>  	else
> diff --git a/arch/arm/mach-omap2/sleep34xx.S b/arch/arm/mach-omap2/sleep34xx.S
> index d18f52e..3335753 100644
> --- a/arch/arm/mach-omap2/sleep34xx.S
> +++ b/arch/arm/mach-omap2/sleep34xx.S
> @@ -150,8 +150,7 @@ ENTRY(omap34xx_cpu_suspend)
>  	stmfd	sp!, {r4 - r11, lr}	@ save registers on stack
>  
>  	/*
> -	 * r0 contains CPU context save/restore pointer in sdram
> -	 * r1 contains information about saving context:
> +	 * r0 contains information about saving context:
>  	 *   0 - No context lost
>  	 *   1 - Only L1 and logic lost
>  	 *   2 - Only L2 lost (Even L1 is retained we clean it along with L2)
> @@ -159,18 +158,11 @@ ENTRY(omap34xx_cpu_suspend)
>  	 */
>  
>  	/* Directly jump to WFI is the context save is not required */
> -	cmp	r1, #0x0
> +	cmp	r0, #0x0
>  	beq	omap3_do_wfi
>  
>  	/* Otherwise fall through to the save context code */
>  save_context_wfi:
> -	mov	r8, r0			@ Store SDRAM address in r8
> -	mrc	p15, 0, r5, c1, c0, 1	@ Read Auxiliary Control Register
> -	mov	r4, #0x1		@ Number of parameters for restore call
> -	stmia	r8!, {r4-r5}		@ Push parameters for restore call
> -	mrc	p15, 1, r5, c9, c0, 2	@ Read L2 AUX ctrl register
> -	stmia	r8!, {r4-r5}		@ Push parameters for restore call
> -
>  	/*
>  	 * jump out to kernel flush routine
>  	 *  - reuse that code is better