linux-kernel - Re: [PATCH v3 1/7] PM/Domains: Add support for retrieving genpd performance states information

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Message-ID: <CAPDyKFr76VHypqGxYL-1HS3uu3_KYeO+dGJ7q1Nj=uXiQgY98A@mail.gmail.com>
Date:   Thu, 17 Oct 2019 10:49:07 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Thara Gopinath <thara.gopinath@...aro.org>
Cc:     Eduardo Valentin <edubezval@...il.com>,
        Zhang Rui <rui.zhang@...el.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Andy Gross <agross@...nel.org>, amit.kucheria@...durent.com,
        Mark Rutland <mark.rutland@....com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux PM <linux-pm@...r.kernel.org>,
        DTML <devicetree@...r.kernel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 1/7] PM/Domains: Add support for retrieving genpd
 performance states information

On Wed, 16 Oct 2019 at 21:37, Thara Gopinath <thara.gopinath@...aro.org> 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.
>
> Signed-off-by: Thara Gopinath <thara.gopinath@...aro.org>

Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>

Kind regards
Uffe


> ---
>  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 cc85e87..507e530 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 baf02ff..e88e57f 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
> --
> 2.1.4
>