[PATCH] OMAP3 PM: Disable SR only during Device Retention/OFF

[PATCH] OMAP3 PM: Disable SR only during Device Retention/OFF

[Vishwanath BS]

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@ti.com>
---
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) {

RE: [PATCH] OMAP3 PM: Disable SR only during Device Retention/OFF

[Sripathy, Vishwanath]

Kevin,
Can you pls take this patch if there are no comments?

Regards
Vishwa

> -----Original Message-----
> From: linux-omap-owner@vger.kernel.org [mailto:linux-omap-
> owner@vger.kernel.org] On Behalf Of Sripathy, Vishwanath
> Sent: Thursday, January 07, 2010 11:22 AM
> To: linux-omap@vger.kernel.org
> Subject: [PATCH] OMAP3 PM: Disable SR only during Device Retention/OFF
> 
> 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@ti.com>
> ---
> 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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Re: [PATCH] OMAP3 PM: Disable SR only during Device Retention/OFF

[Kevin Hilman]

Vishwanath BS <vishwanath.bs@ti.com> 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@ti.com>

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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