PM/domains: add delayed power off capability

- this commit adds a capability to delay the powering off
of the domain
- callers can use pm_genpd_set_poweroff_delay to set the
power off delay for a domain
- it also adds a pm_notifier per pm domain which cancels
the delayed power off work when system suspend is invoked
- this needs to be done since pm_wq is freezable and causes
resume to fail since no one cancels the delayed power off
work. as a result, this work is run after resume when pm_wq
is unfreezed causing unwanted issues

bug 887332

Change-Id: I1befaa6d898f535e969a564ddae12e22ffc69e2d
Signed-off-by: Mayuresh Kulkarni <mkulkarni@nvidia.com>
Reviewed-on: http://git-master/r/202037
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: Arto Merilainen <amerilainen@nvidia.com>

1 files changed, 78 insertions, 5 deletions

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index d1dce3d1c39d..88e2759dbe25 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -629,6 +629,19 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd)
 	return ret;
 }
 
+static int __pm_genpd_poweroff(struct generic_pm_domain *genpd)
+{
+	int ret = 0;
+
+	mutex_lock(&genpd->lock);
+	genpd->in_progress++;
+	ret = pm_genpd_poweroff(genpd);
+	genpd->in_progress--;
+	mutex_unlock(&genpd->lock);
+
+	return ret;
+}
+
 /**
  * genpd_power_off_work_fn - Power off PM domain whose subdomain count is 0.
  * @work: Work structure used for scheduling the execution of this function.
@@ -645,6 +658,21 @@ static void genpd_power_off_work_fn(struct work_struct *work)
 }
 
 /**
+ * genpd_delayed_power_off_work_fn - Power off PM domain after the delay.
+ * @work: Work structure used for scheduling the execution of this function.
+ */
+static void genpd_delayed_power_off_work_fn(struct work_struct *work)
+{
+	struct generic_pm_domain *genpd;
+	struct delayed_work *delay_work = to_delayed_work(work);
+
+	genpd = container_of(delay_work, struct generic_pm_domain,
+		power_off_delayed_work);
+
+	__pm_genpd_poweroff(genpd);
+}
+
+/**
  * pm_genpd_runtime_suspend - Suspend a device belonging to I/O PM domain.
  * @dev: Device to suspend.
  *
@@ -681,11 +709,11 @@ static int pm_genpd_runtime_suspend(struct device *dev)
 	if (dev->power.irq_safe)
 		return 0;
 
-	mutex_lock(&genpd->lock);
-	genpd->in_progress++;
-	pm_genpd_poweroff(genpd);
-	genpd->in_progress--;
-	mutex_unlock(&genpd->lock);
+	if (genpd->power_off_delay)
+		queue_delayed_work(pm_wq, &genpd->power_off_delayed_work,
+			msecs_to_jiffies(genpd->power_off_delay));
+	else
+		__pm_genpd_poweroff(genpd);
 
 	return 0;
 }
@@ -716,6 +744,12 @@ static int pm_genpd_runtime_resume(struct device *dev)
 	if (dev->power.irq_safe)
 		return genpd_start_dev_no_timing(genpd, dev);
 
+	if (genpd->power_off_delay) {
+		if (delayed_work_pending(&genpd->power_off_delayed_work))
+			cancel_delayed_work_sync(
+				&genpd->power_off_delayed_work);
+	}
+
 	mutex_lock(&genpd->lock);
 	ret = __pm_genpd_poweron(genpd);
 	if (ret) {
@@ -774,6 +808,7 @@ static inline int genpd_dev_pm_qos_notifier(struct notifier_block *nb,
 }
 
 static inline void genpd_power_off_work_fn(struct work_struct *work) {}
+static inline void genpd_delayed_power_off_work_fn(struct work_struct *work) {}
 
 #define pm_genpd_runtime_suspend	NULL
 #define pm_genpd_runtime_resume		NULL
@@ -2145,6 +2180,36 @@ static int pm_genpd_default_thaw(struct device *dev)
 	return cb ? cb(dev) : pm_generic_thaw(dev);
 }
 
+static int pm_genpd_suspend_notifier(struct notifier_block *notifier,
+	unsigned long pm_event, void *unused)
+{
+	struct generic_pm_domain *genpd = container_of(notifier,
+		struct generic_pm_domain, system_suspend_notifier);
+
+	if (!genpd)
+		return NOTIFY_DONE;
+
+	switch (pm_event) {
+	case PM_SUSPEND_PREPARE:
+		if (genpd->power_off_delay) {
+			/* if a domain has scheduled a delayed work */
+			if (delayed_work_pending(
+				&genpd->power_off_delayed_work)) {
+
+				/* cancel it now */
+				cancel_delayed_work_sync(
+					&genpd->power_off_delayed_work);
+
+				/* call its power off */
+				__pm_genpd_poweroff(genpd);
+			}
+		}
+		return NOTIFY_OK;
+	}
+
+	return NOTIFY_DONE;
+}
+
 #else /* !CONFIG_PM_SLEEP */
 
 #define pm_genpd_default_suspend	NULL
@@ -2176,7 +2241,10 @@ void pm_genpd_init(struct generic_pm_domain *genpd,
 	mutex_init(&genpd->lock);
 	genpd->gov = gov;
 	INIT_WORK(&genpd->power_off_work, genpd_power_off_work_fn);
+	INIT_DELAYED_WORK(&genpd->power_off_delayed_work,
+		genpd_delayed_power_off_work_fn);
 	genpd->in_progress = 0;
+	genpd->power_off_delay = 0;
 	atomic_set(&genpd->sd_count, 0);
 	genpd->status = is_off ? GPD_STATE_POWER_OFF : GPD_STATE_ACTIVE;
 	init_waitqueue_head(&genpd->status_wait_queue);
@@ -2218,6 +2286,11 @@ void pm_genpd_init(struct generic_pm_domain *genpd,
 	genpd->dev_ops.freeze_late = pm_genpd_default_freeze_late;
 	genpd->dev_ops.thaw_early = pm_genpd_default_thaw_early;
 	genpd->dev_ops.thaw = pm_genpd_default_thaw;
+#ifdef CONFIG_PM_SLEEP
+	genpd->system_suspend_notifier.notifier_call =
+		pm_genpd_suspend_notifier;
+	register_pm_notifier(&genpd->system_suspend_notifier);
+#endif
 	mutex_lock(&gpd_list_lock);
 	list_add(&genpd->gpd_list_node, &gpd_list);
 	mutex_unlock(&gpd_list_lock);