Re: [PATCH 5/5 v3] OMAP3630: PM: Erratum i583: disable coreoff if < ES1.2

[Nishanth Menon <nm@ti.com>]

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Nishanth Menon had written, on 12/15/2010 06:05 PM, the following:
> Kevin Hilman had written, on 12/15/2010 05:47 PM, the following:
> 
>>> I agree that this additional check in sram_idle should be removed, but
>>> as long as I handle it in omap3_pm_off_mode_enable where the next
>>> states are configured, is'nt that enough or am I missing something?
>>
>> Setting the next states only sets the default states, but CPUidle
>> changes them.
>>
>> Looking closer at omap3_pm_off_mode_enable() though, it already calls
>> into CPUidle and disables the valid bit for any states that have
>> *either* MPU or core off.    You'll probably just need to extend this
>> approach to disable only CORE off state(s).
> Thx. it is clear now. let me see how to clean this up.
k. Does the attached look any better now :)? I have removed the check 
logic from sram_idle path instead made omap3_cpuidle_update_states 
little more generic, updated validity of C state based on errata. This 
now disables just those C states with core OFF on 3630 <ES1.2

in a map, this will now look as follows:
--------+-------+-------+-------+-------+--------+
         | MPU   | Core  | OFF   | OFF Enable-36xx|
         | Dom   | Dom   |       +-------+--------+
C state | State | State | Dis   | ES1.1 | ES 1.2 |
--------+-------+-------+-------+-------+--------+
1       | ON    | ON    | YES   | YES   | YES    |
2       | ON    | ON    | YES   | YES   | YES    |
3       | RET   | ON    | YES   | YES   | YES    |
4       | OFF   | ON    | NO    | YES   | YES    |
5       | RET   | RET   | YES   | YES   | YES    |
6       | OFF   | RET   | NO    | YES   | YES    |
7       | OFF   | OFF   | NO    | NO    | YES    |
--------+-------+-------+-------+-------+--------+

-- 
Regards,
Nishanth Menon

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>From bd3d8decf922d7425b9bc9025c7709a9414ad380 Mon Sep 17 00:00:00 2001
From: Nishanth Menon <nm@ti.com>
Date: Wed, 15 Dec 2010 18:40:29 -0600
Subject: [PATCH 1/2] OMAP3: PM: make omap3_cpuidle_update_states independent of enable_off_mode

Currently omap3_cpuidle_update_states makes whole sale decision
on which C states to update based on enable_off_mode variable
Instead, achieve the same functionality by independently providing
mpu and core deepest states the system is allowed to achieve and
update the idle states accordingly.

Signed-off-by: Nishanth Menon <nm@ti.com>
---
 arch/arm/mach-omap2/cpuidle34xx.c |   19 ++++++++++---------
 arch/arm/mach-omap2/pm.h          |    3 ++-
 arch/arm/mach-omap2/pm34xx.c      |    2 +-
 3 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/arch/arm/mach-omap2/cpuidle34xx.c b/arch/arm/mach-omap2/cpuidle34xx.c
index 0d50b45..f80d3f6 100644
--- a/arch/arm/mach-omap2/cpuidle34xx.c
+++ b/arch/arm/mach-omap2/cpuidle34xx.c
@@ -293,25 +293,26 @@ select_state:
 DEFINE_PER_CPU(struct cpuidle_device, omap3_idle_dev);
 
 /**
- * omap3_cpuidle_update_states - Update the cpuidle states.
+ * omap3_cpuidle_update_states() - Update the cpuidle states
+ * @mpu_deepest_state:	Enable states upto and including this for mpu domain
+ * @core_deepest_state:	Enable states upto and including this for core domain
  *
- * Currently, this function toggles the validity of idle states based upon
- * the flag 'enable_off_mode'. When the flag is set all states are valid.
- * Else, states leading to OFF state set to be invalid.
+ * This goes through the list of states available and enables and disables the
+ * validity of C states based on deepest state that can be achieved for the
+ * variable domain
  */
-void omap3_cpuidle_update_states(void)
+void omap3_cpuidle_update_states(u32 mpu_deepest_state, u32 core_deepest_state)
 {
 	int i;
 
 	for (i = OMAP3_STATE_C1; i < OMAP3_MAX_STATES; i++) {
 		struct omap3_processor_cx *cx = &omap3_power_states[i];
 
-		if (enable_off_mode) {
+		if ((cx->mpu_state >= mpu_deepest_state) &&
+		    (cx->core_state >= core_deepest_state)) {
 			cx->valid = 1;
 		} else {
-			if ((cx->mpu_state == PWRDM_POWER_OFF) ||
-				(cx->core_state	== PWRDM_POWER_OFF))
-				cx->valid = 0;
+			cx->valid = 0;
 		}
 	}
 }
diff --git a/arch/arm/mach-omap2/pm.h b/arch/arm/mach-omap2/pm.h
index aff39d0..3597591 100644
--- a/arch/arm/mach-omap2/pm.h
+++ b/arch/arm/mach-omap2/pm.h
@@ -58,7 +58,8 @@ extern u32 sleep_while_idle;
 #endif
 
 #if defined(CONFIG_CPU_IDLE)
-extern void omap3_cpuidle_update_states(void);
+extern void omap3_cpuidle_update_states(u32 core_deepest_state,
+		u32 core_deepest_state);
 #endif
 
 #if defined(CONFIG_PM_DEBUG) && defined(CONFIG_DEBUG_FS)
diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index 21707c9..84ef71b 100644
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c
@@ -916,7 +916,7 @@ void omap3_pm_off_mode_enable(int enable)
 		state = PWRDM_POWER_RET;
 
 #ifdef CONFIG_CPU_IDLE
-	omap3_cpuidle_update_states();
+	omap3_cpuidle_update_states(state, state);
 #endif
 
 	list_for_each_entry(pwrst, &pwrst_list, node) {
-- 
1.6.3.3


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>From e085afb8523ca52e52b7a631c2b63e2bd6d91661 Mon Sep 17 00:00:00 2001
From: Eduardo Valentin <eduardo.valentin@nokia.com>
Date: Wed, 17 Nov 2010 21:46:01 -0600
Subject: [PATCH 2/2] OMAP3630: PM: Erratum i583: disable coreoff if < ES1.2

Limitation i583: Self_Refresh Exit issue after OFF mode

Issue:
When device is waking up from OFF mode, then SDRC state machine sends
inappropriate sequence violating JEDEC standards.

Impact:
OMAP3630 < ES1.2 is impacted as follows depending on the platform:
CS0: for 38.4MHz as internal sysclk, DDR content seen to be stable, while
	for all other sysclk frequencies, varied levels of instability
	seen based on varied parameters.
CS1: impacted

This patch takes option #3 as recommended by the Silicon erratum:
Avoid core power domain transitioning to OFF mode. Power consumption
impact is expected in this case.
To do this, we route core OFF requests to RET request on the impacted
revisions of silicon.

[nm@ti.com: rebased the code to 2.6.37-rc2- short circuit code changed a bit]
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Eduardo Valentin <eduardo.valentin@nokia.com>
---
 arch/arm/mach-omap2/pm34xx.c |   25 ++++++++++++++++++++++---
 1 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index 84ef71b..ad60105 100644
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c
@@ -56,6 +56,7 @@
 #define OMAP343X_CONTROL_REG_VALUE_OFFSET  0xc8
 
 #define RTA_ERRATUM_i608		(1 << 0)
+#define SDRC_WAKEUP_ERRATUM_i583	(1 << 1)
 static u16 pm34xx_errata;
 #define IS_PM34XX_ERRATUM(id)		(pm34xx_errata & (id))
 
@@ -916,12 +917,28 @@ void omap3_pm_off_mode_enable(int enable)
 		state = PWRDM_POWER_RET;
 
 #ifdef CONFIG_CPU_IDLE
-	omap3_cpuidle_update_states(state, state);
+	/*
+	 * Erratum i583: implementation for ES rev < Es1.2 on 3630. We cannot
+	 * enable OFF mode in a stable form for previous revisions, restrict
+	 * instead to RET
+	 */
+	if (IS_PM34XX_ERRATUM(SDRC_WAKEUP_ERRATUM_i583))
+		omap3_cpuidle_update_states(state, PWRDM_POWER_RET);
+	else
+		omap3_cpuidle_update_states(state, state);
 #endif
 
 	list_for_each_entry(pwrst, &pwrst_list, node) {
-		pwrst->next_state = state;
-		omap_set_pwrdm_state(pwrst->pwrdm, state);
+		if (IS_PM34XX_ERRATUM(SDRC_WAKEUP_ERRATUM_i583) &&
+				pwrst->pwrdm == core_pwrdm &&
+				state == PWRDM_POWER_OFF) {
+			pwrst->next_state = PWRDM_POWER_RET;
+			pr_err("%s: Core OFF disabled due to errata i583\n",
+				__func__);
+		} else {
+			pwrst->next_state = state;
+		}
+		omap_set_pwrdm_state(pwrst->pwrdm, pwrst->next_state);
 	}
 }
 
@@ -999,6 +1016,8 @@ static void __init pm_errata_configure(void)
 		pm34xx_errata |= RTA_ERRATUM_i608;
 		/* Enable the l2 cache toggling in sleep logic */
 		enable_omap3630_toggle_l2_on_restore();
+		if (omap_rev() < OMAP3630_REV_ES1_2)
+			pm34xx_errata |= SDRC_WAKEUP_ERRATUM_i583;
 	}
 }
 
-- 
1.6.3.3