[PATCH v2 1/8] PM / Domains: Make genpd state allocation dynamic

[Lina Iyer]

On Mon, Oct 10 2016 at 02:40 -0600, Ulf Hansson wrote:
>On 8 October 2016 at 00:36, Lina Iyer <lina.iyer at linaro.org> wrote:
>> Allow PM Domain states to be defined dynamically by the drivers. This
>> removes the limitation on the maximum number of states possible for a
>> domain.
>>
>> Cc: Axel Haslam <ahaslam+renesas at baylibre.com>
>> Suggested-by: Ulf Hansson <ulf.hansson at linaro.org>
>> Signed-off-by: Lina Iyer <lina.iyer at linaro.org>
>> ---
>>  arch/arm/mach-imx/gpc.c     | 17 ++++++++++-------
>>  drivers/base/power/domain.c | 36 ++++++++++++++++++++++++------------
>>  include/linux/pm_domain.h   |  5 ++---
>>  3 files changed, 36 insertions(+), 22 deletions(-)
>>
>> diff --git a/arch/arm/mach-imx/gpc.c b/arch/arm/mach-imx/gpc.c
>> index 0df062d..57a410b 100644
>> --- a/arch/arm/mach-imx/gpc.c
>> +++ b/arch/arm/mach-imx/gpc.c
>> @@ -380,13 +380,6 @@ static struct pu_domain imx6q_pu_domain = {
>>                 .name = "PU",
>>                 .power_off = imx6q_pm_pu_power_off,
>>                 .power_on = imx6q_pm_pu_power_on,
>> -               .states = {
>> -                       [0] = {
>> -                               .power_off_latency_ns = 25000,
>> -                               .power_on_latency_ns = 2000000,
>> -                       },
>> -               },
>> -               .state_count = 1,
>>         },
>>  };
>>
>> @@ -430,6 +423,16 @@ static int imx_gpc_genpd_init(struct device *dev, struct regulator *pu_reg)
>>         if (!IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS))
>>                 return 0;
>>
>> +       imx6q_pu_domain.base.states = devm_kzalloc(dev,
>> +                                       sizeof(*imx6q_pu_domain.base.states),
>> +                                       GFP_KERNEL);
>> +       if (!imx6q_pu_domain.base.states)
>> +               return -ENOMEM;
>> +
>> +       imx6q_pu_domain.base.states[0].power_off_latency_ns = 25000;
>> +       imx6q_pu_domain.base.states[0].power_on_latency_ns = 2000000;
>> +       imx6q_pu_domain.base.state_count = 1;
>> +
>>         pm_genpd_init(&imx6q_pu_domain.base, NULL, false);
>>         return of_genpd_add_provider_onecell(dev->of_node,
>>                                              &imx_gpc_onecell_data);
>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
>> index e023066..4e87170 100644
>> --- a/drivers/base/power/domain.c
>> +++ b/drivers/base/power/domain.c
>> @@ -1282,6 +1282,21 @@ out:
>>  }
>>  EXPORT_SYMBOL_GPL(pm_genpd_remove_subdomain);
>>
>> +static int genpd_set_default_power_state(struct generic_pm_domain *genpd)
>> +{
>> +       struct genpd_power_state *state;
>> +
>> +       state = kzalloc(sizeof(*state), GFP_KERNEL);
>> +       if (!state)
>> +               return -ENOMEM;
>> +
>> +       genpd->states = state;
>> +       genpd->state_count = 1;
>> +       genpd->free = state;
>> +
>> +       return 0;
>> +}
>> +
>>  /**
>>   * pm_genpd_init - Initialize a generic I/O PM domain object.
>>   * @genpd: PM domain object to initialize.
>> @@ -1293,6 +1308,8 @@ EXPORT_SYMBOL_GPL(pm_genpd_remove_subdomain);
>>  int pm_genpd_init(struct generic_pm_domain *genpd,
>>                   struct dev_power_governor *gov, bool is_off)
>>  {
>> +       int ret;
>> +
>>         if (IS_ERR_OR_NULL(genpd))
>>                 return -EINVAL;
>>
>> @@ -1325,19 +1342,12 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
>>                 genpd->dev_ops.start = pm_clk_resume;
>>         }
>>
>> -       if (genpd->state_idx >= GENPD_MAX_NUM_STATES) {
>> -               pr_warn("Initial state index out of bounds.\n");
>> -               genpd->state_idx = GENPD_MAX_NUM_STATES - 1;
>> -       }
>> -
>> -       if (genpd->state_count > GENPD_MAX_NUM_STATES) {
>> -               pr_warn("Limiting states to  %d\n", GENPD_MAX_NUM_STATES);
>> -               genpd->state_count = GENPD_MAX_NUM_STATES;
>> -       }
>> -
>>         /* Use only one "off" state if there were no states declared */
>> -       if (genpd->state_count == 0)
>> -               genpd->state_count = 1;
>> +       if (genpd->state_count == 0) {
>> +               ret = genpd_set_default_power_state(genpd);
>> +               if (ret)
>> +                       return ret;
>> +       }
>>
>>         mutex_lock(&gpd_list_lock);
>>         list_add(&genpd->gpd_list_node, &gpd_list);
>> @@ -1374,6 +1384,8 @@ static int genpd_remove(struct generic_pm_domain *genpd)
>>                 kfree(link);
>>         }
>>
>> +       kfree(genpd->free);
>> +
>
>To be safe, let's move this after cancel_work_sync() - as to prevent
>no accesses is made to ->states pointer after you have freed it.
>
OK

Thanks,
Lina

>>         list_del(&genpd->gpd_list_node);
>>         mutex_unlock(&genpd->lock);
>>         cancel_work_sync(&genpd->power_off_work);
>> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
>> index a09fe5c..de1d8f3 100644
>> --- a/include/linux/pm_domain.h
>> +++ b/include/linux/pm_domain.h
>> @@ -19,8 +19,6 @@
>>  /* Defines used for the flags field in the struct generic_pm_domain */
>>  #define GENPD_FLAG_PM_CLK      (1U << 0) /* PM domain uses PM clk */
>>
>> -#define GENPD_MAX_NUM_STATES   8 /* Number of possible low power states */
>> -
>>  enum gpd_status {
>>         GPD_STATE_ACTIVE = 0,   /* PM domain is active */
>>         GPD_STATE_POWER_OFF,    /* PM domain is off */
>> @@ -70,9 +68,10 @@ struct generic_pm_domain {
>>         void (*detach_dev)(struct generic_pm_domain *domain,
>>                            struct device *dev);
>>         unsigned int flags;             /* Bit field of configs for genpd */
>> -       struct genpd_power_state states[GENPD_MAX_NUM_STATES];
>> +       struct genpd_power_state *states;
>>         unsigned int state_count; /* number of states */
>>         unsigned int state_idx; /* state that genpd will go to when off */
>> +       void *free; /* Free the state that was allocated for default */
>>
>>  };
>>
>> --
>> 2.7.4
>>
>
>After the minor change suggested above, you may add my ack.
>
>Kind regards
>Uffe