On Wed, Dec 21, 2022 at 10:43:59PM +0530, Akhil P Oommen wrote:
> From: Ulf Hansson <ulf.hans...@linaro.org>
>
> 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.hans...@linaro.org>
> Signed-off-by: Akhil P Oommen <quic_akhi...@quicinc.com>
Reviewed-by: Bjorn Andersson <anders...@kernel.org>
@Rafael, would you be willing to share an immutable branch with this
change? Or would you be okay with me doing so from the qcom clock tree?
Regards,
Bjorn
> ---
>
> Changes in v4:
> - Update genpd function documentation (Ulf)
>
> Changes in v2:
> - Minor formatting fix
>
> drivers/base/power/domain.c | 26 ++++++++++++++++++++++++++
> include/linux/pm_domain.h | 5 +++++
> 2 files changed, 31 insertions(+)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 967bcf9d415e..84662d338188 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -519,6 +519,31 @@ 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.
> + *
> + * It is assumed that the users guarantee that the genpd wouldn't be detached
> + * while this routine is getting called.
> + */
> +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 +587,7 @@ 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
>
