On 4 March 2016 at 12:23, Jon Hunter <jonathanh@xxxxxxxxxx> wrote:
> The genpd framework allows users to add PM domains via the pm_genpd_init()
> function, however, there is no corresponding function to remove a PM
> domain. For most devices this may be fine as the PM domains are never
> removed, however, for devices that wish to populate the PM domains from
> within a driver, having the ability to remove a PM domain if the probing
> of the device fails or the driver is unloaded is necessary.
>
> Add the function pm_genpd_remove() to remove a PM domain by referencing
> it's generic_pm_domain structure.
>
> If a device supports nested or subdomains, then the PM domains
> should be removed in reverse order to ensure that the subdomains are
> removed first. Hence, add the function pm_genpd_remove_tail() to remove
> the last PM domain added by a given provider and return the
> generic_pm_domain structure for the PM domain that was removed.
Perhaps split this up, so the pm_genpd_remove_tail() gets added in a
separate patch on top.
>
> PM domains can only be removed if they are not a parent domain to
> another PM domain and have no devices associated with them.
>
> When removing PM domains, the PM domain will also be removed from the
> list of providers, if it was registered.
>
> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx>
> ---
> drivers/base/power/domain.c | 96 +++++++++++++++++++++++++++++++++++++++++++++
> include/linux/pm_domain.h | 12 ++++++
> 2 files changed, 108 insertions(+)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 9b33377bf01b..17090e1c91d6 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1556,6 +1556,102 @@ void pm_genpd_init(struct generic_pm_domain *genpd,
> }
> EXPORT_SYMBOL_GPL(pm_genpd_init);
>
> +/**
> + * __pm_genpd_remove - Remove a generic I/O PM domain
> + * @genpd: Pointer to PM domain that is to be removed.
> + *
> + * To remove the PM domain, this function:
> + * - Removes the PM domain from the list of providers, if registered.
> + * - Removes the PM domain as a subdomain to any parent domains,
> + * if it was added.
> + * - Removes the PM domain from the list of registered PM domains.
> + *
> + * The PM domain will only be removed, if it is not a parent to any
> + * other PM domain and has no devices associated with it. Must be called
> + * with the gpd_list_lock held.
> + */
> +static int __pm_genpd_remove(struct generic_pm_domain *genpd)
Please rename to genpd_remove() as it's a static function.
> +{
> + struct gpd_link *l, *link;
> + int ret = 0;
> +
> + if (IS_ERR_OR_NULL(genpd))
> + return -EINVAL;
> +
> + if (genpd->provider_data)
> + of_genpd_del_provider_by_data(genpd->provider_data);
> +
> + mutex_lock(&genpd->lock);
> +
> + if (!list_empty(&genpd->master_links) || genpd->device_count) {
> + mutex_unlock(&genpd->lock);
> + pr_err("%s: unable to remove %s\n", __func__, genpd->name);
> + return -EBUSY;
> + }
> +
> + list_for_each_entry_safe(link, l, &genpd->slave_links, slave_node) {
> + list_del(&link->master_node);
> + list_del(&link->slave_node);
> + kfree(link);
> + }
> +
> + list_del(&genpd->gpd_list_node);
> + mutex_unlock(&genpd->lock);
> + cancel_work_sync(&genpd->power_off_work);
> + pr_debug("%s: removed %s\n", __func__, genpd->name);
> +
> + return ret;
> +}
> +
> +/**
> + * pm_genpd_remove - Remove a generic I/O PM domain
> + * @genpd: Pointer to PM domain that is to be removed.
> + */
> +int pm_genpd_remove(struct generic_pm_domain *genpd)
> +{
> + int ret;
> +
> + mutex_lock(&gpd_list_lock);
> + ret = __pm_genpd_remove(genpd);
> + mutex_unlock(&gpd_list_lock);
> +
> + return ret;
> +}
> +
> +/**
> + * pm_genpd_remove_tail - Remove the last PM domain registered for a provider
> + * @provider: Pointer to device structure associated with provider
> + *
> + * Find the last PM domain that was added by the provider whose 'provider'
> + * device structure matches the device structure given. The 'provider'
> + * device structure for a given PM domain should be initialised by the
> + * device that is creating the PM domains and hence, calling
> + * pm_genpd_init().
Maybe make this a bigger "Important note" as what is needed to
actually benefit from using this function.
> + *
> + * Returns a valid pointer to struct generic_pm_domain on success or
> + * ERR_PTR() on failure.
> + */
> +struct generic_pm_domain *pm_genpd_remove_tail(struct device *provider)
> +{
> + struct generic_pm_domain *g, *gpd, *genpd = ERR_PTR(-ENOENT);
> + int ret;
> +
> + if (IS_ERR_OR_NULL(provider))
> + return ERR_PTR(-EINVAL);
> +
> + mutex_lock(&gpd_list_lock);
> + list_for_each_entry_safe(gpd, g, &gpd_list, gpd_list_node) {
> + if (gpd->provider == provider) {
> + ret = __pm_genpd_remove(gpd);
> + genpd = ret ? ERR_PTR(ret) : gpd;
> + break;
> + }
> + }
> + mutex_unlock(&gpd_list_lock);
> +
> + return genpd;
> +}
> +
> #ifdef CONFIG_PM_GENERIC_DOMAINS_OF
> /*
> * Device Tree based PM domain providers.
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index 7b7921a65cb0..78b23718392f 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -53,6 +53,7 @@ struct generic_pm_domain {
> struct mutex lock;
> struct dev_power_governor *gov;
> struct work_struct power_off_work;
> + struct device *provider; /* Identity of the domain provider */
> void *provider_data;
> const char *name;
> atomic_t sd_count; /* Number of subdomains with power "on" */
> @@ -132,6 +133,8 @@ extern int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
> struct generic_pm_domain *target);
> extern void pm_genpd_init(struct generic_pm_domain *genpd,
> struct dev_power_governor *gov, bool is_off);
> +extern int pm_genpd_remove(struct generic_pm_domain *genpd);
> +extern struct generic_pm_domain *pm_genpd_remove_tail(struct device *provider);
>
> extern struct dev_power_governor simple_qos_governor;
> extern struct dev_power_governor pm_domain_always_on_gov;
> @@ -166,6 +169,15 @@ static inline void pm_genpd_init(struct generic_pm_domain *genpd,
> struct dev_power_governor *gov, bool is_off)
> {
> }
> +static inline int pm_genpd_remove(struct generic_pm_domain *genpd)
> +{
> + return -ENOTSUPP;
> +}
> +static inline
> +struct generic_pm_domain *pm_genpd_remove_tail(struct device *provider)
> +{
> + return ERR_PTR(-ENOTSUPP);
> +}
> #endif
>
> static inline int pm_genpd_add_device(struct generic_pm_domain *genpd,
> --
> 2.1.4
>
Kind regards
Uffe
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