From: Sylwester Nawrocki s.nawrocki@samsung.com
This patch adds notifiers to the runtime PM/genpd subsystem. It is now possible to register a notifier, which will be called before and after the generic power domain subsystem calls the power domain's power_on and power_off callbacks.
Signed-off-by: Sylwester Nawrocki s.nawrocki@samsung.com --- Documentation/power/notifiers.txt | 14 ++++++++ drivers/base/power/domain.c | 70 ++++++++++++++++++++++++++++++++++++--- include/linux/pm.h | 2 ++ include/linux/pm_domain.h | 19 +++++++++++ 4 files changed, 101 insertions(+), 4 deletions(-)
diff --git a/Documentation/power/notifiers.txt b/Documentation/power/notifiers.txt index a81fa25..62303f6 100644 --- a/Documentation/power/notifiers.txt +++ b/Documentation/power/notifiers.txt @@ -53,3 +53,17 @@ NULL). To register and/or unregister a suspend notifier use the functions register_pm_notifier() and unregister_pm_notifier(), respectively, defined in include/linux/suspend.h . If you don't need to unregister the notifier, you can also use the pm_notifier() macro defined in include/linux/suspend.h . + +Power Domain notifiers +---------------------- + +The power domain notifiers allow subsystems or drivers to register for power +domain on/off notifications, should they need to perform any actions right +before or right after the power domain on/off. The device must be already +added to a power domain before its subsystem or driver registers the notifier. +Following events are supported: + +PM_GENPD_POWER_ON_PREPARE The power domain is about to turn on. +PM_GENPD_POST_POWER_ON The power domain has just turned on. +PM_GENPD_POWER_OFF_PREPARE The power domain is about to turn off. +PM_GENPD_POST_POWER_OFF The power domain has just turned off. diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index eee55c1..5fe0966 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -70,6 +70,45 @@ static struct generic_pm_domain *pm_genpd_lookup_name(const char *domain_name) return genpd; }
+int pm_genpd_register_notifier(struct device *dev, struct notifier_block *nb) +{ + struct pm_domain_data *pdd; + int ret = -EINVAL; + + spin_lock_irq(&dev->power.lock); + if (dev->power.subsys_data) { + pdd = dev->power.subsys_data->domain_data; + ret = blocking_notifier_chain_register(&pdd->notify_chain_head, + nb); + } + spin_unlock_irq(&dev->power.lock); + return ret; +} +EXPORT_SYMBOL_GPL(pm_genpd_register_notifier); + +void pm_genpd_unregister_notifier(struct device *dev, struct notifier_block *nb) +{ + struct pm_domain_data *pdd; + + spin_lock_irq(&dev->power.lock); + if (dev->power.subsys_data) { + pdd = dev->power.subsys_data->domain_data; + blocking_notifier_chain_unregister(&pdd->notify_chain_head, nb); + } + spin_unlock_irq(&dev->power.lock); +} +EXPORT_SYMBOL_GPL(pm_genpd_unregister_notifier); + +static void pm_genpd_notifier_call(unsigned long event, + struct generic_pm_domain *genpd) +{ + struct pm_domain_data *pdd; + + list_for_each_entry(pdd, &genpd->dev_list, list_node) + blocking_notifier_call_chain(&pdd->notify_chain_head, + event, pdd->dev); +} + #ifdef CONFIG_PM
struct generic_pm_domain *dev_to_genpd(struct device *dev) @@ -231,10 +270,14 @@ static int __pm_genpd_poweron(struct generic_pm_domain *genpd) ktime_t time_start = ktime_get(); s64 elapsed_ns;
+ pm_genpd_notifier_call(PM_GENPD_POWER_ON_PREPARE, genpd); + ret = genpd->power_on(genpd); if (ret) goto err;
+ pm_genpd_notifier_call(PM_GENPD_POST_POWER_ON, genpd); + elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start)); if (elapsed_ns > genpd->power_on_latency_ns) { genpd->power_on_latency_ns = elapsed_ns; @@ -554,13 +597,17 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd) * the pm_genpd_poweron() restore power for us (this shouldn't * happen very often). */ + pm_genpd_notifier_call(PM_GENPD_POWER_OFF_PREPARE, genpd); + ret = genpd->power_off(genpd); if (ret == -EBUSY) { genpd_set_active(genpd); goto out; } - elapsed_ns = ktime_to_ns(ktime_sub(ktime_get(), time_start)); + + pm_genpd_notifier_call(PM_GENPD_POST_POWER_OFF, genpd); + if (elapsed_ns > genpd->power_off_latency_ns) { genpd->power_off_latency_ns = elapsed_ns; genpd->max_off_time_changed = true; @@ -837,9 +884,13 @@ static void pm_genpd_sync_poweroff(struct generic_pm_domain *genpd) || atomic_read(&genpd->sd_count) > 0) return;
- if (genpd->power_off) + if (genpd->power_off) { + pm_genpd_notifier_call(PM_GENPD_POWER_OFF_PREPARE, genpd); genpd->power_off(genpd);
+ pm_genpd_notifier_call(PM_GENPD_POST_POWER_OFF, genpd); + } + genpd->status = GPD_STATE_POWER_OFF;
list_for_each_entry(link, &genpd->slave_links, slave_node) { @@ -869,8 +920,11 @@ static void pm_genpd_sync_poweron(struct generic_pm_domain *genpd) genpd_sd_counter_inc(link->master); }
- if (genpd->power_on) + if (genpd->power_on) { + pm_genpd_notifier_call(PM_GENPD_POWER_ON_PREPARE, genpd); genpd->power_on(genpd); + pm_genpd_notifier_call(PM_GENPD_POST_POWER_ON, genpd); + }
genpd->status = GPD_STATE_ACTIVE; } @@ -1292,9 +1346,16 @@ static int pm_genpd_restore_noirq(struct device *dev) * If the domain was off before the hibernation, make * sure it will be off going forward. */ - if (genpd->power_off) + if (genpd->power_off) { + pm_genpd_notifier_call(PM_GENPD_POWER_OFF_PREPARE, + genpd); + genpd->power_off(genpd);
+ pm_genpd_notifier_call(PM_GENPD_POST_POWER_OFF, + genpd); + } + return 0; } } @@ -1467,6 +1528,7 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, spin_unlock_irq(&dev->power.lock);
mutex_lock(&gpd_data->lock); + BLOCKING_INIT_NOTIFIER_HEAD(&gpd_data->base.notify_chain_head); gpd_data->base.dev = dev; list_add_tail(&gpd_data->base.list_node, &genpd->dev_list); gpd_data->need_restore = genpd->status == GPD_STATE_POWER_OFF; diff --git a/include/linux/pm.h b/include/linux/pm.h index 72c0fe0..bfc55d4 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -22,6 +22,7 @@ #define _LINUX_PM_H
#include <linux/list.h> +#include <linux/notifier.h> #include <linux/workqueue.h> #include <linux/spinlock.h> #include <linux/wait.h> @@ -542,6 +543,7 @@ struct wakeup_source; struct pm_domain_data { struct list_head list_node; struct device *dev; + struct blocking_notifier_head notify_chain_head; };
struct pm_subsys_data { diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h index 7c1d252..569ab16 100644 --- a/include/linux/pm_domain.h +++ b/include/linux/pm_domain.h @@ -17,6 +17,12 @@ #include <linux/notifier.h> #include <linux/cpuidle.h>
+/* PM domain state transition notifications */ +#define PM_GENPD_POWER_ON_PREPARE 0x01 +#define PM_GENPD_POST_POWER_ON 0x02 +#define PM_GENPD_POWER_OFF_PREPARE 0x03 +#define PM_GENPD_POST_POWER_OFF 0x04 + enum gpd_status { GPD_STATE_ACTIVE = 0, /* PM domain is active */ GPD_STATE_WAIT_MASTER, /* PM domain's master is being waited for */ @@ -167,6 +173,11 @@ extern int pm_genpd_name_poweron(const char *domain_name);
extern bool default_stop_ok(struct device *dev);
+extern int pm_genpd_register_notifier(struct device *dev, + struct notifier_block *nb); +extern void pm_genpd_unregister_notifier(struct device *dev, + struct notifier_block *nb); + extern struct dev_power_governor pm_domain_always_on_gov; #else
@@ -259,6 +270,14 @@ static inline bool default_stop_ok(struct device *dev) { return false; } +static inline int pm_genpd_register_notifier(struct device *dev, + struct notifier_block *nb) +{ + return -ENOSYS; +} +static inline void pm_genpd_unregister_notifier(struct device *dev, + struct notifier_block *nb) {} + #define simple_qos_governor NULL #define pm_domain_always_on_gov NULL #endif