On Thu 19 Mar 18:41 PDT 2020, Thara Gopinath wrote:
> Add two new APIs in the genpd framework, dev_pm_genpd_get_performance_state
> to return the current performance state of a power domain and
> dev_pm_genpd_performance_state_count to return the total number of
> performance states supported by a power domain. Since the genpd framework
> does not maintain a count of number of performance states supported by a
> power domain, introduce a new callback(.get_performance_state_count) that
> can be used to retrieve this information from power domain drivers.
>
> These APIs are added to aid the implementation of a power domain as a
> warming device. Linux kernel cooling device framework(into which warming
> device can be plugged in) requires during initialization to be provided
> with the maximum number of states that can be supported. When a power
> domain acts as a warming device, the max state is the max number of
> perfomrance states supported by the power domain. The cooling device
> framework implements API to retrieve the current state of the cooling
> device. This in turn translates to the current performance state of the
> power domain.
>
> Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Signed-off-by: Thara Gopinath <thara.gopinath@xxxxxxxxxx>
Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> ---
> drivers/base/power/domain.c | 37 +++++++++++++++++++++++++++++++++++++
> include/linux/pm_domain.h | 13 +++++++++++++
> 2 files changed, 50 insertions(+)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 959d6d5eb000..d0297c48fa79 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -408,6 +408,43 @@ int dev_pm_genpd_set_performance_state(struct device *dev, unsigned int state)
> }
> EXPORT_SYMBOL_GPL(dev_pm_genpd_set_performance_state);
>
> +int dev_pm_genpd_get_performance_state(struct device *dev)
> +{
> + struct generic_pm_domain *genpd;
> + unsigned int state;
> +
> + genpd = dev_to_genpd_safe(dev);
> + if (IS_ERR(genpd))
> + return -ENODEV;
> +
> + genpd_lock(genpd);
> + state = genpd->performance_state;
> + genpd_unlock(genpd);
> +
> + return state;
> +}
> +EXPORT_SYMBOL_GPL(dev_pm_genpd_get_performance_state);
> +
> +int dev_pm_genpd_performance_state_count(struct device *dev)
> +{
> + struct generic_pm_domain *genpd;
> + int count;
> +
> + genpd = dev_to_genpd_safe(dev);
> + if (IS_ERR(genpd))
> + return -ENODEV;
> +
> + if (unlikely(!genpd->get_performance_state_count))
> + return -EINVAL;
> +
> + genpd_lock(genpd);
> + count = genpd->get_performance_state_count(genpd);
> + genpd_unlock(genpd);
> +
> + return count;
> +}
> +EXPORT_SYMBOL_GPL(dev_pm_genpd_performance_state_count);
> +
> static int _genpd_power_on(struct generic_pm_domain *genpd, bool timed)
> {
> unsigned int state_idx = genpd->state_idx;
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index 9ec78ee53652..7d415350380f 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -117,6 +117,7 @@ struct generic_pm_domain {
> struct dev_pm_opp *opp);
> int (*set_performance_state)(struct generic_pm_domain *genpd,
> unsigned int state);
> + int (*get_performance_state_count)(struct generic_pm_domain *genpd);
> struct gpd_dev_ops dev_ops;
> s64 max_off_time_ns; /* Maximum allowed "suspended" time. */
> bool max_off_time_changed;
> @@ -204,6 +205,8 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
> struct dev_power_governor *gov, bool is_off);
> int pm_genpd_remove(struct generic_pm_domain *genpd);
> int dev_pm_genpd_set_performance_state(struct device *dev, unsigned int state);
> +int dev_pm_genpd_get_performance_state(struct device *dev);
> +int dev_pm_genpd_performance_state_count(struct device *dev);
>
> extern struct dev_power_governor simple_qos_governor;
> extern struct dev_power_governor pm_domain_always_on_gov;
> @@ -251,6 +254,16 @@ static inline int dev_pm_genpd_set_performance_state(struct device *dev,
> return -ENOTSUPP;
> }
>
> +static inline int dev_pm_genpd_get_performance_state(struct device *dev)
> +{
> + return -ENOTSUPP;
> +}
> +
> +static inline int dev_pm_genpd_performance_state_count(struct device *dev)
> +{
> + return -ENOTSUPP;
> +}
> +
> #define simple_qos_governor (*(struct dev_power_governor *)(NULL))
> #define pm_domain_always_on_gov (*(struct dev_power_governor *)(NULL))
> #endif
> --
> 2.20.1
>
