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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-12-17 02:54:26 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-12-21 03:11:12 +0100
commita436b6a19f57656a6557439523923d89eb4a880d (patch)
tree62637a13b7721a775f8aa2af4554c9fc3069f595
parentd89d7ff9edf58cbf8ad0f490694b2edea8eb3a39 (diff)
downloadlinux-aarch64-a436b6a19f57656a6557439523923d89eb4a880d.tar.gz
PM / runtime: Add new helper for conditional usage count incrementation
Introduce a new runtime PM function, pm_runtime_get_if_in_use(), that will increment the device's runtime PM usage counter and return 1 if its status is RPM_ACTIVE and its usage counter is greater than 0 at the same time (0 will be returned otherwise). This is useful for things that should only be done if the device is active (from the runtime PM perspective) and used by somebody (as indicated by the usage counter) already and they are not worth bothering otherwise. Requested-by: Imre Deak <imre.deak@intel.com> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--Documentation/power/runtime_pm.txt6
-rw-r--r--drivers/base/power/runtime.c24
-rw-r--r--include/linux/pm_runtime.h5
3 files changed, 35 insertions, 0 deletions
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt
index 0784bc3a2ab5..7328cf85236c 100644
--- a/Documentation/power/runtime_pm.txt
+++ b/Documentation/power/runtime_pm.txt
@@ -371,6 +371,12 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h:
- increment the device's usage counter, run pm_runtime_resume(dev) and
return its result
+ int pm_runtime_get_if_in_use(struct device *dev);
+ - return -EINVAL if 'power.disable_depth' is nonzero; otherwise, if the
+ 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
+
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 ab3fcd9f6c98..4c7055009bd6 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -966,6 +966,30 @@ 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.
+ * @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.
+ */
+int pm_runtime_get_if_in_use(struct device *dev)
+{
+ 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);
+ spin_unlock_irqrestore(&dev->power.lock, flags);
+ return retval;
+}
+EXPORT_SYMBOL_GPL(pm_runtime_get_if_in_use);
+
+/**
* __pm_runtime_set_status - Set runtime PM status of a device.
* @dev: Device to handle.
* @status: New runtime PM status of the device.
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
index 3bdbb4189780..7af093d6a4dd 100644
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -39,6 +39,7 @@ 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_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);
@@ -143,6 +144,10 @@ static inline int pm_schedule_suspend(struct device *dev, unsigned int delay)
{
return -ENOSYS;
}
+static inline int pm_runtime_get_if_in_use(struct device *dev)
+{
+ 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; }