On 12/21/2022 8:13 PM, Ulf Hansson wrote:
> On Tue, 20 Dec 2022 at 08:44, Akhil P Oommen <quic_akhilpo@xxxxxxxxxxx> wrote:
>> From: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
>>
>> Some genpd providers doesn't ensure that it has turned off at hardware.
>> This is fine until the consumer really requires during some special
>> scenarios that the power domain collapse at hardware before it is
>> turned ON again.
>>
>> An example is the reset sequence of Adreno GPU which requires that the
>> 'gpucc cx gdsc' power domain should move to OFF state in hardware at
>> least once before turning in ON again to clear the internal state.
>>
>> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
>> Signed-off-by: Akhil P Oommen <quic_akhilpo@xxxxxxxxxxx>
>> ---
>>
>> (no changes since v2)
>>
>> Changes in v2:
>> - Minor formatting fix
>>
>> drivers/base/power/domain.c | 23 +++++++++++++++++++++++
>> include/linux/pm_domain.h | 5 +++++
>> 2 files changed, 28 insertions(+)
>>
>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>> index 967bcf9d415e..53524a102321 100644
>> --- a/drivers/base/power/domain.c
>> +++ b/drivers/base/power/domain.c
>> @@ -519,6 +519,28 @@ ktime_t dev_pm_genpd_get_next_hrtimer(struct device *dev)
>> }
>> EXPORT_SYMBOL_GPL(dev_pm_genpd_get_next_hrtimer);
>>
>> +/*
>> + * dev_pm_genpd_synced_poweroff - Next power off should be synchronous
>> + *
>> + * @dev: A device that is attached to the genpd.
>> + *
>> + * Allows a consumer of the genpd to notify the provider that the next power off
>> + * should be synchronous.
> Nitpick; similar to other dev_pm_genpd_* function-descriptions, I
> think it's important to add the below information.
>
> "It is assumed that the users guarantee that the genpd wouldn't be
> detached while this routine is getting called."
>
> Can you please add that?
Thanks. Fixed in revision 4.
-Akhil.
>
>> + */
>> +void dev_pm_genpd_synced_poweroff(struct device *dev)
>> +{
>> + struct generic_pm_domain *genpd;
>> +
>> + genpd = dev_to_genpd_safe(dev);
>> + if (!genpd)
>> + return;
>> +
>> + genpd_lock(genpd);
>> + genpd->synced_poweroff = true;
>> + genpd_unlock(genpd);
>> +}
>> +EXPORT_SYMBOL_GPL(dev_pm_genpd_synced_poweroff);
>> +
>> static int _genpd_power_on(struct generic_pm_domain *genpd, bool timed)
>> {
>> unsigned int state_idx = genpd->state_idx;
>> @@ -562,6 +584,7 @@ static int _genpd_power_on(struct generic_pm_domain *genpd, bool timed)
>>
>> out:
>> raw_notifier_call_chain(&genpd->power_notifiers, GENPD_NOTIFY_ON, NULL);
>> + genpd->synced_poweroff = false;
>> return 0;
>> err:
>> raw_notifier_call_chain(&genpd->power_notifiers, GENPD_NOTIFY_OFF,
>> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
>> index 1cd41bdf73cf..f776fb93eaa0 100644
>> --- a/include/linux/pm_domain.h
>> +++ b/include/linux/pm_domain.h
>> @@ -136,6 +136,7 @@ struct generic_pm_domain {
>> unsigned int prepared_count; /* Suspend counter of prepared devices */
>> unsigned int performance_state; /* Aggregated max performance state */
>> cpumask_var_t cpus; /* A cpumask of the attached CPUs */
>> + bool synced_poweroff; /* A consumer needs a synced poweroff */
>> int (*power_off)(struct generic_pm_domain *domain);
>> int (*power_on)(struct generic_pm_domain *domain);
>> struct raw_notifier_head power_notifiers; /* Power on/off notifiers */
>> @@ -235,6 +236,7 @@ int dev_pm_genpd_add_notifier(struct device *dev, struct notifier_block *nb);
>> int dev_pm_genpd_remove_notifier(struct device *dev);
>> void dev_pm_genpd_set_next_wakeup(struct device *dev, ktime_t next);
>> ktime_t dev_pm_genpd_get_next_hrtimer(struct device *dev);
>> +void dev_pm_genpd_synced_poweroff(struct device *dev);
>>
>> extern struct dev_power_governor simple_qos_governor;
>> extern struct dev_power_governor pm_domain_always_on_gov;
>> @@ -300,6 +302,9 @@ static inline ktime_t dev_pm_genpd_get_next_hrtimer(struct device *dev)
>> {
>> return KTIME_MAX;
>> }
>> +static inline void dev_pm_genpd_synced_poweroff(struct device *dev)
>> +{ }
>> +
>> #define simple_qos_governor (*(struct dev_power_governor *)(NULL))
>> #define pm_domain_always_on_gov (*(struct dev_power_governor *)(NULL))
>> #endif
>> --
>> 2.7.4
>>
> Kind regards
> Uffe
