Vishwanath BS <vishwanath.bs@xxxxxx> writes:
> Currently in omap_sram_idle function, SR is disabled whenever next state
> is retention/OFF w/o checking whether system can really enter retention/off.
> This patch adds another condition to disable SR. Basically FCLK register for
> Core and PER are checked before disabling SR. THis will give some more power
> savings in MP3 usecase (where Core enters retention where as PER does not).
>
> Tested OMAP3430 ZOOM2
>
> Signed-off-by: Vishwanath BS <Vishwanath.bs@xxxxxx>
I'm not going to take this one in it's current form as we had
discussions about this kind of thing earler when Tero had a series of
adding various fclk checks into the idle path.
I'm holding off on this patch until Tero's series is reviewed/merged.
He has added some functionality to check idleness of clockdomains and
powerdomains that could be used here.
Kevin
> ---
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> index 3868cdf..13c5dfb
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -479,6 +479,7 @@ void omap_sram_idle(void)
> int mpu_logic_state, mpu_mem_state, core_logic_state, core_mem_state;
> u32 sdrc_pwr = 0;
> int per_state_modified = 0;
> + u32 fclk_status;
>
> if (!_omap_sram_idle)
> return;
> @@ -545,15 +546,6 @@ void omap_sram_idle(void)
> if (pwrdm_read_pwrst(cam_pwrdm) == PWRDM_POWER_ON)
> omap2_clkdm_deny_idle(mpu_pwrdm->pwrdm_clkdms[0]);
>
> - /*
> - * Disable smartreflex before entering WFI.
> - * Only needed if we are going to enter retention or off.
> - */
> - if (mpu_next_state <= PWRDM_POWER_RET)
> - disable_smartreflex(SR1);
> - if (core_next_state <= PWRDM_POWER_RET)
> - disable_smartreflex(SR2);
> -
> /* CORE */
> if (core_next_state < PWRDM_POWER_ON) {
> omap_uart_prepare_idle(0, core_next_state & core_logic_state);
> @@ -600,6 +592,21 @@ void omap_sram_idle(void)
> omap3_intc_prepare_idle();
>
> /*
> + * Disable smartreflex before entering WFI.
> + * Only needed if we are going to enter retention or off.
> + */
> + fclk_status = cm_read_mod_reg(OMAP3430_PER_MOD, CM_FCLKEN) |
> + cm_read_mod_reg(CORE_MOD, CM_FCLKEN1) |
> + cm_read_mod_reg(CORE_MOD, OMAP3430ES2_CM_FCLKEN3);
> +
> + if (!fclk_status) {
> + if (mpu_next_state <= PWRDM_POWER_RET)
> + disable_smartreflex(SR1);
> + if (core_next_state <= PWRDM_POWER_RET)
> + disable_smartreflex(SR2);
> + }
> +
> + /*
> * On EMU/HS devices ROM code restores a SRDC value
> * from scratchpad which has automatic self refresh on timeout
> * of AUTO_CNT = 1 enabled. This takes care of errata 1.142.
> @@ -685,11 +692,12 @@ void omap_sram_idle(void)
> * Enable smartreflex after WFI. Only needed if we entered
> * retention or off
> */
> - if (mpu_next_state <= PWRDM_POWER_RET)
> - enable_smartreflex(SR1);
> - if (core_next_state <= PWRDM_POWER_RET)
> - enable_smartreflex(SR2);
> -
> + if (!fclk_status) {
> + if (mpu_next_state <= PWRDM_POWER_RET)
> + enable_smartreflex(SR1);
> + if (core_next_state <= PWRDM_POWER_RET)
> + enable_smartreflex(SR2);
> + }
> /* PER */
> if (per_next_state < PWRDM_POWER_ON) {
> if (per_next_state == PWRDM_POWER_OFF) {
> --
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