PM / Runtime: Implement autosuspend support

This patch (as1427) implements the "autosuspend" facility for runtime
PM.  A few new fields are added to the dev_pm_info structure and
several new PM helper functions are defined, for telling the PM core
whether or not a device uses autosuspend, for setting the autosuspend
delay, and for marking periods of device activity.

Drivers that do not want to use autosuspend can continue using the
same helper functions as before; their behavior will not change.  In
addition, drivers supporting autosuspend can also call the old helper
functions to get the old behavior.

The details are all explained in Documentation/power/runtime_pm.txt
and Documentation/ABI/testing/sysfs-devices-power.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

2 files changed, 53 insertions, 0 deletions

diff --git a/include/linux/pm.h b/include/linux/pm.h
index abd81ff..40f3f45 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -444,6 +444,9 @@ enum rpm_status {
  *
  * RPM_REQ_SUSPEND	Run the device bus type's ->runtime_suspend() callback
  *
+ * RPM_REQ_AUTOSUSPEND	Same as RPM_REQ_SUSPEND, but not until the device has
+ *			been inactive for as long as power.autosuspend_delay
+ *
  * RPM_REQ_RESUME	Run the device bus type's ->runtime_resume() callback
  */
 
@@ -451,6 +454,7 @@ enum rpm_request {
 	RPM_REQ_NONE = 0,
 	RPM_REQ_IDLE,
 	RPM_REQ_SUSPEND,
+	RPM_REQ_AUTOSUSPEND,
 	RPM_REQ_RESUME,
 };
 
@@ -482,9 +486,13 @@ struct dev_pm_info {
 	unsigned int		run_wake:1;
 	unsigned int		runtime_auto:1;
 	unsigned int		no_callbacks:1;
+	unsigned int		use_autosuspend:1;
+	unsigned int		timer_autosuspends:1;
 	enum rpm_request	request;
 	enum rpm_status		runtime_status;
 	int			runtime_error;
+	int			autosuspend_delay;
+	unsigned long		last_busy;
 	unsigned long		active_jiffies;
 	unsigned long		suspended_jiffies;
 	unsigned long		accounting_timestamp;
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
index 8ca52f7..99ed1aa 100644
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -12,12 +12,15 @@
 #include <linux/device.h>
 #include <linux/pm.h>
 
+#include <linux/jiffies.h>
+
 /* Runtime PM flag argument bits */
 #define RPM_ASYNC		0x01	/* Request is asynchronous */
 #define RPM_NOWAIT		0x02	/* Don't wait for concurrent
 					    state change */
 #define RPM_GET_PUT		0x04	/* Increment/decrement the
 					    usage_count */
+#define RPM_AUTO		0x08	/* Use autosuspend_delay */
 
 #ifdef CONFIG_PM_RUNTIME
 
@@ -37,6 +40,9 @@ extern int pm_generic_runtime_idle(struct device *dev);
 extern int pm_generic_runtime_suspend(struct device *dev);
 extern int pm_generic_runtime_resume(struct device *dev);
 extern void pm_runtime_no_callbacks(struct device *dev);
+extern void __pm_runtime_use_autosuspend(struct device *dev, bool use);
+extern void pm_runtime_set_autosuspend_delay(struct device *dev, int delay);
+extern unsigned long pm_runtime_autosuspend_expiration(struct device *dev);
 
 static inline bool pm_children_suspended(struct device *dev)
 {
@@ -74,6 +80,11 @@ static inline bool pm_runtime_suspended(struct device *dev)
 	return dev->power.runtime_status == RPM_SUSPENDED;
 }
 
+static inline void pm_runtime_mark_last_busy(struct device *dev)
+{
+	ACCESS_ONCE(dev->power.last_busy) = jiffies;
+}
+
 #else /* !CONFIG_PM_RUNTIME */
 
 static inline int __pm_runtime_idle(struct device *dev, int rpmflags)
@@ -113,6 +124,14 @@ static inline int pm_generic_runtime_suspend(struct device *dev) { return 0; }
 static inline int pm_generic_runtime_resume(struct device *dev) { return 0; }
 static inline void pm_runtime_no_callbacks(struct device *dev) {}
 
+static inline void pm_runtime_mark_last_busy(struct device *dev) {}
+static inline void __pm_runtime_use_autosuspend(struct device *dev,
+						bool use) {}
+static inline void pm_runtime_set_autosuspend_delay(struct device *dev,
+						int delay) {}
+static inline unsigned long pm_runtime_autosuspend_expiration(
+				struct device *dev) { return 0; }
+
 #endif /* !CONFIG_PM_RUNTIME */
 
 static inline int pm_runtime_idle(struct device *dev)
@@ -125,6 +144,11 @@ static inline int pm_runtime_suspend(struct device *dev)
 	return __pm_runtime_suspend(dev, 0);
 }
 
+static inline int pm_runtime_autosuspend(struct device *dev)
+{
+	return __pm_runtime_suspend(dev, RPM_AUTO);
+}
+
 static inline int pm_runtime_resume(struct device *dev)
 {
 	return __pm_runtime_resume(dev, 0);
@@ -155,11 +179,22 @@ static inline int pm_runtime_put(struct device *dev)
 	return __pm_runtime_idle(dev, RPM_GET_PUT | RPM_ASYNC);
 }
 
+static inline int pm_runtime_put_autosuspend(struct device *dev)
+{
+	return __pm_runtime_suspend(dev,
+	    RPM_GET_PUT | RPM_ASYNC | RPM_AUTO);
+}
+
 static inline int pm_runtime_put_sync(struct device *dev)
 {
 	return __pm_runtime_idle(dev, RPM_GET_PUT);
 }
 
+static inline int pm_runtime_put_sync_autosuspend(struct device *dev)
+{
+	return __pm_runtime_suspend(dev, RPM_GET_PUT | RPM_AUTO);
+}
+
 static inline int pm_runtime_set_active(struct device *dev)
 {
 	return __pm_runtime_set_status(dev, RPM_ACTIVE);
@@ -175,4 +210,14 @@ static inline void pm_runtime_disable(struct device *dev)
 	__pm_runtime_disable(dev, true);
 }
 
+static inline void pm_runtime_use_autosuspend(struct device *dev)
+{
+	__pm_runtime_use_autosuspend(dev, true);
+}
+
+static inline void pm_runtime_dont_use_autosuspend(struct device *dev)
+{
+	__pm_runtime_use_autosuspend(dev, false);
+}
+
 #endif