[PATCH v4 7/7] OMAP3630: PM: Erratum i583: disable coreoff if < ES1.2

[Jean Pihet]

On Mon, Dec 20, 2010 at 7:51 AM, Santosh Shilimkar
<santosh.shilimkar at ti.com> wrote:
>> -----Original Message-----
>> From: linux-omap-owner at vger.kernel.org [mailto:linux-omap-
>> owner at vger.kernel.org] On Behalf Of Nishanth Menon
>> Sent: Sunday, December 19, 2010 4:24 AM
>> To: linux-omap; linux-arm
>> Cc: Jean Pihet; Kevin; Tony
>> Subject: [PATCH v4 7/7] OMAP3630: PM: Erratum i583: disable coreoff if <
>> ES1.2
>>
>> From: Eduardo Valentin <eduardo.valentin at nokia.com>
>>
>> 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 at ti.com: rebased the code to 2.6.37-rc2- short circuit code changed a
>> bit]
>> Signed-off-by: Nishanth Menon <nm at ti.com>
>> Signed-off-by: Eduardo Valentin <eduardo.valentin at nokia.com>
>> ---
>> v4: idle state control changed a bit -we wont register or enable
>>     the states which cannot be enabled.
>> v3: http://marc.info/?t=129140247800027&r=1&w=2
>>     no functional change in erratum wa implementation, just registration
>> of
>>       erratum is collated to a single cpu detection and version check
>> v2: https://patchwork.kernel.org/patch/365262/
>>     rebased to this patch series instead of depending on hs changes
>>     fix typo for macro definition
>> v1: http://marc.info/?l=linux-omap&m=129013173425266&w=2
>>  arch/arm/mach-omap2/cpuidle34xx.c |   10 ++++++++++
>>  arch/arm/mach-omap2/pm.h          |    1 +
>>  arch/arm/mach-omap2/pm34xx.c      |   24 +++++++++++++++++++++---
>>  3 files changed, 32 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/arm/mach-omap2/cpuidle34xx.c b/arch/arm/mach-
>> omap2/cpuidle34xx.c
>> index f80d3f6..1b32e98 100644
>> --- a/arch/arm/mach-omap2/cpuidle34xx.c
>> +++ b/arch/arm/mach-omap2/cpuidle34xx.c
>> @@ -453,6 +453,16 @@ void omap_init_power_states(void)
>>       omap3_power_states[OMAP3_STATE_C7].core_state = PWRDM_POWER_OFF;
>>       omap3_power_states[OMAP3_STATE_C7].flags = CPUIDLE_FLAG_TIME_VALID
> |
>>                               CPUIDLE_FLAG_CHECK_BM;
>> +
>> +     /*
>> +      * Erratum i583: implementation for ES rev < Es1.2 on 3630. We
>> cannot
>> +      * enable OFF mode in a stable form for previous revisions.
>> +      * we disable C7 state as a result.
>> +      */
>> +     if (IS_PM34XX_ERRATUM(PM_SDRC_WAKEUP_ERRATUM_i583)) {
>> +             omap3_power_states[OMAP3_STATE_C7].valid = 0;
>> +             cpuidle_params_table[OMAP3_STATE_C7].valid = 0;
> WARN_ONCE in IDLE also would be good.

Agree on the WARN_ONCE remarks.

Other than that:
Acked-by: Jean Pihet <j-pihet at ti.com>

>> +     }
>>  }
>>
>>  struct cpuidle_driver omap3_idle_driver = {
>> diff --git a/arch/arm/mach-omap2/pm.h b/arch/arm/mach-omap2/pm.h
>> index 92ef400..9032d09 100644
>> --- a/arch/arm/mach-omap2/pm.h
>> +++ b/arch/arm/mach-omap2/pm.h
>> @@ -87,6 +87,7 @@ extern unsigned int omap24xx_cpu_suspend_sz;
>>  extern unsigned int omap34xx_cpu_suspend_sz;
>>
>>  #define PM_RTA_ERRATUM_i608          (1 << 0)
>> +#define PM_SDRC_WAKEUP_ERRATUM_i583  (1 << 1)
>>
>>  #if defined(CONFIG_PM) && defined(CONFIG_ARCH_OMAP3)
>>  extern u16 pm34xx_errata;
>> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
>> index 21cd36e..7faea55 100644
>> --- a/arch/arm/mach-omap2/pm34xx.c
>> +++ b/arch/arm/mach-omap2/pm34xx.c
>> @@ -928,12 +928,28 @@ 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(PM_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(PM_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",
> Shoud we do this in every iteration or just WARN_ONCE do ??
>> +                             __func__);
>> +             } else {
>> +                     pwrst->next_state = state;
>> +             }
>> +             omap_set_pwrdm_state(pwrst->pwrdm, pwrst->next_state);
>>       }
>>  }
>>
>> @@ -1011,6 +1027,8 @@ static void __init pm_errata_configure(void)
>>               pm34xx_errata |= PM_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 |= PM_SDRC_WAKEUP_ERRATUM_i583;
>>       }
>>  }
>>
>> --
>> 1.6.3.3
>>
>> --
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