linux-kernel - Re: [PATCH V2 3/5] PM / Domains: Save OPP table pointer in genpd

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Message-ID: <CAPDyKFrUBwagtfwCezqw2ujPBVVtQNqz4rKgAG0Yyy18FZv+wA@mail.gmail.com>
Date:   Fri, 30 Nov 2018 09:53:07 +0100
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Kevin Hilman <khilman@...nel.org>,
        Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Niklas Cassel <niklas.cassel@...aro.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2 3/5] PM / Domains: Save OPP table pointer in genpd

On Mon, 26 Nov 2018 at 09:10, Viresh Kumar <viresh.kumar@...aro.org> wrote:
>
> We will need these going forward in hotpath, i.e. from within
> dev_pm_genpd_set_performance_state().

Well, as for patch2, please try to be a bit more descriptive of why
and what this patch does.

>
> Lets fetch and save them while the OPP tables are added.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
>  drivers/base/power/domain.c | 23 +++++++++++++++++++++--
>  include/linux/pm_domain.h   |  2 ++
>  2 files changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 8e554e6a82a2..0d928359b880 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1907,12 +1907,21 @@ int of_genpd_add_provider_simple(struct device_node *np,
>                                 ret);
>                         goto unlock;
>                 }
> +
> +               /*
> +                * Save table for faster processing while setting performance
> +                * state.
> +                */
> +               genpd->opp_table = dev_pm_opp_get_opp_table(&genpd->dev);
> +               WARN_ON(!genpd->opp_table);

The WARN_ON seems lazy. Why not implement a proper error path?

>         }
>
>         ret = genpd_add_provider(np, genpd_xlate_simple, genpd);
>         if (ret) {
> -               if (genpd->set_performance_state)
> +               if (genpd->set_performance_state) {
> +                       dev_pm_opp_put_opp_table(genpd->opp_table);
>                         dev_pm_opp_of_remove_table(&genpd->dev);
> +               }
>
>                 goto unlock;
>         }
> @@ -1965,6 +1974,13 @@ int of_genpd_add_provider_onecell(struct device_node *np,
>                                         i, ret);
>                                 goto error;
>                         }
> +
> +                       /*
> +                        * Save table for faster processing while setting
> +                        * performance state.
> +                        */
> +                       genpd->opp_table = dev_pm_opp_get_opp_table_indexed(&genpd->dev, i);
> +                       WARN_ON(!genpd->opp_table);
>                 }
>
>                 genpd->provider = &np->fwnode;
> @@ -1989,8 +2005,10 @@ int of_genpd_add_provider_onecell(struct device_node *np,
>                 genpd->provider = NULL;
>                 genpd->has_provider = false;
>
> -               if (genpd->set_performance_state)
> +               if (genpd->set_performance_state) {
> +                       dev_pm_opp_put_opp_table(genpd->opp_table);
>                         dev_pm_opp_of_remove_table(&genpd->dev);
> +               }
>         }
>
>         mutex_unlock(&gpd_list_lock);
> @@ -2024,6 +2042,7 @@ void of_genpd_del_provider(struct device_node *np)
>                                         if (!gpd->set_performance_state)
>                                                 continue;
>
> +                                       dev_pm_opp_put_opp_table(gpd->opp_table);
>                                         dev_pm_opp_of_remove_table(&gpd->dev);
>                                 }
>                         }
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index 642036952553..9ad101362aef 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -73,6 +73,7 @@ struct genpd_power_state {
>
>  struct genpd_lock_ops;
>  struct dev_pm_opp;
> +struct opp_table;
>
>  struct generic_pm_domain {
>         struct device dev;
> @@ -94,6 +95,7 @@ struct generic_pm_domain {
>         unsigned int performance_state; /* Aggregated max performance state */
>         int (*power_off)(struct generic_pm_domain *domain);
>         int (*power_on)(struct generic_pm_domain *domain);
> +       struct opp_table *opp_table;    /* OPP table of the genpd */
>         unsigned int (*opp_to_performance_state)(struct generic_pm_domain *genpd,
>                                                  struct dev_pm_opp *opp);
>         int (*set_performance_state)(struct generic_pm_domain *genpd,
> --
> 2.19.1.568.g152ad8e3369a
>

Similar as for patch2, this makes sense to me. Although, let me review
the complete series before giving a final call.

Kind regards
Uffe