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Commit 3fe57710 authored by Jon Hunter's avatar Jon Hunter Committed by Rafael J. Wysocki
Browse files

PM / Domains: Add support for removing PM domains 



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. Note that the bulk of the code that
removes the PM domain is placed in a separate local function
genpd_remove() (which is called by pm_genpd_remove()). The code is
structured in this way to prepare for adding another function to remove
a PM domain by provider that will also call genpd_remove(). Note that
users of genpd_remove() must call this function with the mutex,
gpd_list_lock, held.

PM domains can only be removed if the associated provider has been
removed, they are not a parent domain to another PM domain and have no
devices associated with them.

Signed-off-by: default avatarJon Hunter <jonathanh@nvidia.com>
Acked-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent de0aa06d

drivers/base/power/domain.c

+60 −0
Original line number Diff line number Diff line
@@ -1358,6 +1358,66 @@ int pm_genpd_init(struct generic_pm_domain *genpd, 
}

EXPORT_SYMBOL_GPL(pm_genpd_init);



static int genpd_remove(struct generic_pm_domain *genpd)

{

	struct gpd_link *l, *link;



	if (IS_ERR_OR_NULL(genpd))

		return -EINVAL;



	mutex_lock(&genpd->lock);



	if (genpd->has_provider) {

		mutex_unlock(&genpd->lock);

		pr_err("Provider present, unable to remove %s\n", genpd->name);

		return -EBUSY;

	}



	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 0;

}



/**

 * 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 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 the associated provider has

 * been removed, it is not a parent to any other PM domain and has no

 * devices associated with it.

 */

int pm_genpd_remove(struct generic_pm_domain *genpd)

{

	int ret;



	mutex_lock(&gpd_list_lock);

	ret = genpd_remove(genpd);

	mutex_unlock(&gpd_list_lock);



	return ret;

}

EXPORT_SYMBOL_GPL(pm_genpd_remove);



#ifdef CONFIG_PM_GENERIC_DOMAINS_OF



typedef struct generic_pm_domain *(*genpd_xlate_t)(struct of_phandle_args *args,

include/linux/pm_domain.h

+5 −0
Original line number Diff line number Diff line
@@ -130,6 +130,7 @@ extern int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd, 
				     struct generic_pm_domain *target);

extern int 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 dev_power_governor simple_qos_governor;

extern struct dev_power_governor pm_domain_always_on_gov;
@@ -165,6 +166,10 @@ static inline int pm_genpd_init(struct generic_pm_domain *genpd, 
{

	return -ENOSYS;

}

static inline int pm_genpd_remove(struct generic_pm_domain *genpd)

{

	return -ENOTSUPP;

}

#endif



static inline int pm_genpd_add_device(struct generic_pm_domain *genpd,