[PATCH 2/2] OMAP3: Implemented VFP restore/save context

[Sripathy, Vishwanath]

> -----Original Message-----
> From: linux-omap-owner at vger.kernel.org [mailto:linux-omap-
> owner at vger.kernel.org] On Behalf Of Tero Kristo
> Sent: Tuesday, November 24, 2009 4:07 PM
> To: linux-arm-kernel at lists.infradead.org
> Cc: linux-omap at vger.kernel.org
> Subject: [PATCH 2/2] OMAP3: Implemented VFP restore/save context
> 
> From: Tero Kristo <tero.kristo at nokia.com>
> 
> VFP save context is called before MPU/NEON off. Restore is not needed as
> the next VFP trap will restore context automatically. Uses the support
> routine implemented in arch/arm/vfp/vfpmodule.c.
> 
> Signed-off-by: Tero Kristo <tero.kristo at nokia.com>
> Acked-by: Tony Lindgren <tony at atomide.com>
> Cc: Vishwanath Sripathy <vishwanath.bs at ti.com>
> Cc: Rajendra Nayak <rnayak at ti.com>
> Cc: Richard Woodruff <r-woodruff2 at ti.com>
> Cc: Peter 'p2' De Schrijver <peter.de-schrijver at nokia.com>
> ---
>  arch/arm/mach-omap2/pm.h     |    1 +
>  arch/arm/mach-omap2/pm34xx.c |   21 ++++++++++++++++++++-
>  2 files changed, 21 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/pm.h b/arch/arm/mach-omap2/pm.h
> index 4f22107..dd5bbaf 100644
> --- a/arch/arm/mach-omap2/pm.h
> +++ b/arch/arm/mach-omap2/pm.h
> @@ -18,6 +18,7 @@ extern u32 sleep_while_idle;
>  extern u32 voltage_off_while_idle;
> 
>  extern void *omap3_secure_ram_storage;
> +extern void vfp_pm_save_context(void);
>  extern void omap3_pm_off_mode_enable(int);
>  extern void omap_sram_idle(void);
>  extern int omap3_can_sleep(void);
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> index b26ae5b..4b01303 100644
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -321,6 +321,18 @@ static void restore_control_register(u32 val)
>  	__asm__ __volatile__ ("mcr p15, 0, %0, c1, c0, 0" : : "r" (val));
>  }
> 
> +static inline void omap3_save_neon_context(void)
> +{
> +#ifdef CONFIG_VFP
> +	vfp_pm_save_context();
> +#endif
> +}
> +
> +static inline void omap3_restore_neon_context(void)
> +{
> +	return;
> +}
> +
>  /* Function to restore the table entry that was modified for enabling MMU */
>  static void restore_table_entry(void)
>  {
> @@ -365,6 +377,7 @@ void omap_sram_idle(void)
>  	/* save_state = 3 => L1, L2 and logic lost */
>  	int save_state = 0;
>  	int mpu_next_state = PWRDM_POWER_ON;
> +	int neon_next_state = PWRDM_POWER_ON;
>  	int per_next_state = PWRDM_POWER_ON;
>  	int core_next_state = PWRDM_POWER_ON;
>  	int core_prev_state, per_prev_state;
> @@ -398,8 +411,12 @@ void omap_sram_idle(void)
>  	pwrdm_pre_transition();
> 
>  	/* NEON control */
> -	if (pwrdm_read_pwrst(neon_pwrdm) == PWRDM_POWER_ON)
> +	if (pwrdm_read_pwrst(neon_pwrdm) == PWRDM_POWER_ON) {
>  		pwrdm_set_next_pwrst(neon_pwrdm, mpu_next_state);
> +		neon_next_state = mpu_next_state;
> +		if (neon_next_state == PWRDM_POWER_OFF)
> +			omap3_save_neon_context();
> +	}
> 
>  	/* PER */
>  	per_next_state = pwrdm_read_next_pwrst(per_pwrdm);
> @@ -537,6 +554,8 @@ void omap_sram_idle(void)
>  		omap3_disable_io_chain();
>  	}
> 
> +	if (neon_next_state == PWRDM_POWER_OFF)
> +		omap3_restore_neon_context();
> 
Why do call restore here when restore is done automatically upon context switch?

>  	pwrdm_post_transition();
>  }
> --
> 1.5.4.3
> 
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