Nishanth Menon <nm@xxxxxx> writes: > From: Eduardo Valentin <eduardo.valentin@xxxxxxxxx> > > 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@xxxxxx: rebased the code to 2.6.37-rc2- short circuit code changed a bit] > Signed-off-by: Nishanth Menon <nm@xxxxxx> > Signed-off-by: Eduardo Valentin <eduardo.valentin@xxxxxxxxx> > --- > v4: idle state control changed a bit -we wont register or enable > the states which cannot be enabled. I like this version. Thanks. > 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; > + } > } > > 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", > + __func__); This is a warning, not an error condition, so should probably be pr_warning(). That being said, this could be noisy if enable_off_mode is being toggled repeatedly, so using WARN_ONCE() might be more appropriate as suggested by others. Kevin > + } 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; > } > } -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
