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PM / Domains: Add support for removing PM domains

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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: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Jon Hunter 2016-09-12 12:01:13 +01:00 committed by Rafael J. Wysocki
parent de0aa06d8b
commit 3fe577107c
2 changed files with 65 additions and 0 deletions
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60
drivers/base/power/domain.c
View File

@ -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,

5
include/linux/pm_domain.h
View File

@ -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,