PM: runtime: Introduce pm_runtime_blocked()

Introduce a new helper function called pm_runtime_blocked()
for checking the power.last_status value indicating whether or not
enabling runtime PM for the given device has been blocked (which
happens in the "prepare" phase of system-wide suspend if runtime
PM is disabled for the given device at that point).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://patch.msgid.link/4632087.LvFx2qVVIh@rjwysocki.net

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 797ea38ceba7..c0f5a9f89299 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1555,6 +1555,23 @@ out:
 }
 EXPORT_SYMBOL_GPL(pm_runtime_enable);
 
+bool pm_runtime_blocked(struct device *dev)
+{
+	bool ret;
+
+	/*
+	 * dev->power.last_status is a bit field, so in case it is updated via
+	 * RMW, read it under the spin lock.
+	 */
+	spin_lock_irq(&dev->power.lock);
+
+	ret = dev->power.last_status == RPM_BLOCKED;
+
+	spin_unlock_irq(&dev->power.lock);
+
+	return ret;
+}
+
 static void pm_runtime_disable_action(void *data)
 {
 	pm_runtime_dont_use_autosuspend(data);