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Subject[PATCH 01/29] pm: Add PM domain notifications
Date
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
--
1.9.2


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