[RESEND PATCH 1/1] PM-runtime: Add pm_runtime_get_if_active

[Sakari Ailus <sakari.ailus@linux.intel.com>]

pm_runtime_get_if_in_use() bumps the usage count if the usage count is
non-zero and the device's runtime PM status is active. This works for
drivers that do not use autoidle, but for those that do, the function
returns zero even when the device is active.

In order to maintain sane device state while the device is powered on in
hope it'll be needed, pm_runtime_get_if_active(dev, true) returns greater
than zero if the device was in active state when it was called, in which
case it also increments the device's usage_count.

If the second argument of pm_runtime_get_if_active() is false, the function
acts just as pm_runtime_get_if_in_use() does. This patch also makes the
latter as a wrapper for the former.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
This time cc'ing linux-pm as well.

 Documentation/power/runtime_pm.rst |  6 +++++
 drivers/base/power/runtime.c       | 36 ++++++++++++++++++++++--------
 include/linux/pm_runtime.h         | 12 +++++++++-
 3 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/Documentation/power/runtime_pm.rst b/Documentation/power/runtime_pm.rst
index ab8406c84254..0553008b6279 100644
--- a/Documentation/power/runtime_pm.rst
+++ b/Documentation/power/runtime_pm.rst
@@ -382,6 +382,12 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h:
       nonzero, increment the counter and return 1; otherwise return 0 without
       changing the counter
 
+  `int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count);`
+    - return -EINVAL if 'power.disable_depth' is nonzero; otherwise, if the
+      runtime PM status is RPM_ACTIVE, and either ign_usage_count is true
+      or the device's usage_count is non-zero, increment the counter and
+      return 1; otherwise return 0 without changing the counter
+
   `void pm_runtime_put_noidle(struct device *dev);`
     - decrement the device's usage counter
 
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 16134a69bf6f..99c7da112c95 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1087,29 +1087,47 @@ int __pm_runtime_resume(struct device *dev, int rpmflags)
 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
 
 /**
- * pm_runtime_get_if_in_use - Conditionally bump up the device's usage counter.
+ * pm_runtime_get_if_active - Conditionally bump up the device's usage counter.
  * @dev: Device to handle.
  *
  * Return -EINVAL if runtime PM is disabled for the device.
  *
- * If that's not the case and if the device's runtime PM status is RPM_ACTIVE
- * and the runtime PM usage counter is nonzero, increment the counter and
- * return 1.  Otherwise return 0 without changing the counter.
+ * Otherwise, if the device's runtime PM status is RPM_ACTIVE and either
+ * ign_usage_count is true or the device's usage_count is non-zero, increment
+ * the counter and return 1. Otherwise return 0 without changing the counter.
+ *
+ * If ign_usage_count is true, the function can be used to prevent suspending
+ * the device when its runtime PM status is RPM_ACTIVE.
+ *
+ * If ign_usage_count is false, the function can be used to prevent suspending
+ * the device when both its runtime PM status is RPM_ACTIVE and its usage_count
+ * is non-zero.
+ *
+ * The caller is resposible for putting the device's usage count when ther
+ * return value is greater than zero.
  */
-int pm_runtime_get_if_in_use(struct device *dev)
+int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count)
 {
 	unsigned long flags;
 	int retval;
 
 	spin_lock_irqsave(&dev->power.lock, flags);
-	retval = dev->power.disable_depth > 0 ? -EINVAL :
-		dev->power.runtime_status == RPM_ACTIVE
-			&& atomic_inc_not_zero(&dev->power.usage_count);
+	if (dev->power.disable_depth > 0) {
+		retval = -EINVAL;
+	} else if (dev->power.runtime_status != RPM_ACTIVE) {
+		retval = 0;
+	} else if (ign_usage_count) {
+		retval = 1;
+		atomic_inc(&dev->power.usage_count);
+	} else {
+		retval = atomic_inc_not_zero(&dev->power.usage_count);
+	}
 	trace_rpm_usage_rcuidle(dev, 0);
 	spin_unlock_irqrestore(&dev->power.lock, flags);
+
 	return retval;
 }
-EXPORT_SYMBOL_GPL(pm_runtime_get_if_in_use);
+EXPORT_SYMBOL_GPL(pm_runtime_get_if_active);
 
 /**
  * __pm_runtime_set_status - Set runtime PM status of a device.
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
index 22af69d237a6..3bdcbce8141a 100644
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -38,7 +38,7 @@ extern int pm_runtime_force_resume(struct device *dev);
 extern int __pm_runtime_idle(struct device *dev, int rpmflags);
 extern int __pm_runtime_suspend(struct device *dev, int rpmflags);
 extern int __pm_runtime_resume(struct device *dev, int rpmflags);
-extern int pm_runtime_get_if_in_use(struct device *dev);
+extern int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count);
 extern int pm_schedule_suspend(struct device *dev, unsigned int delay);
 extern int __pm_runtime_set_status(struct device *dev, unsigned int status);
 extern int pm_runtime_barrier(struct device *dev);
@@ -60,6 +60,11 @@ extern void pm_runtime_put_suppliers(struct device *dev);
 extern void pm_runtime_new_link(struct device *dev);
 extern void pm_runtime_drop_link(struct device *dev);
 
+static inline int pm_runtime_get_if_in_use(struct device *dev)
+{
+	return pm_runtime_get_if_active(dev, false);
+}
+
 static inline void pm_suspend_ignore_children(struct device *dev, bool enable)
 {
 	dev->power.ignore_children = enable;
@@ -143,6 +148,11 @@ static inline int pm_runtime_get_if_in_use(struct device *dev)
 {
 	return -EINVAL;
 }
+static inline int pm_runtime_get_if_active(struct device *dev,
+					   bool ign_usage_count)
+{
+	return -EINVAL;
+}
 static inline int __pm_runtime_set_status(struct device *dev,
 					    unsigned int status) { return 0; }
 static inline int pm_runtime_barrier(struct device *dev) { return 0; }
-- 
2.20.1