linux-kernel - Re: [PATCH] cpufreq: drivers with target_index() must set freq

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Message-ID: <CAJZ5v0h4AUP92Wuprfoy2ErhiktTvRquyc9-iMwzt6d=HaqYMg@mail.gmail.com>
Date:   Mon, 3 Apr 2023 17:28:20 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>, linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Yajun Deng <yajun.deng@...ux.dev>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] cpufreq: drivers with target_index() must set freq_table

On Mon, Apr 3, 2023 at 6:09 AM Viresh Kumar <viresh.kumar@...aro.org> wrote:
>
> Since the cpufreq core directly uses freq_table, for cpufreq drivers
> that set their target_index() callback, make it mandatory for them to
> set the same.
>
> Since this is set per policy and normally from policy->init(), do this
> from cpufreq_table_validate_and_sort() which gets called right after
> ->init().
>
> Reported-by: Yajun Deng <yajun.deng@...ux.dev>
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
>  drivers/cpufreq/cpufreq.c    | 5 +++++
>  drivers/cpufreq/freq_table.c | 9 ++++++++-
>  2 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 6d8fd3b8dcb5..09131c54703f 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -73,6 +73,11 @@ static inline bool has_target(void)
>         return cpufreq_driver->target_index || cpufreq_driver->target;
>  }
>
> +bool has_target_index(void)
> +{
> +       return !!cpufreq_driver->target_index;
> +}

This needs to go into a header (as a static inline) or the prototype
of it needs to go into a header.

> +
>  /* internal prototypes */
>  static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
>  static int cpufreq_init_governor(struct cpufreq_policy *policy);
> diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
> index 90bfc27ed1ba..c6fc5b0ea91f 100644
> --- a/drivers/cpufreq/freq_table.c
> +++ b/drivers/cpufreq/freq_table.c
> @@ -10,6 +10,8 @@
>  #include <linux/cpufreq.h>
>  #include <linux/module.h>
>
> +bool has_target_index(void);
> +
>  /*********************************************************************
>   *                     FREQUENCY TABLE HELPERS                       *
>   *********************************************************************/
> @@ -355,8 +357,13 @@ int cpufreq_table_validate_and_sort(struct cpufreq_policy *policy)
>  {
>         int ret;
>
> -       if (!policy->freq_table)
> +       if (!policy->freq_table) {
> +               /* Freq table must be passed by drivers with target_index() */
> +               if (has_target_index())
> +                       return -EINVAL;
> +
>                 return 0;
> +       }
>
>         ret = cpufreq_frequency_table_cpuinfo(policy, policy->freq_table);
>         if (ret)
> --
> 2.31.1.272.g89b43f80a514
>