PM-runtime: add tracepoints for usage_count changes

Add tracepoints to remaining places where device's power.usage_count
is changed.

This helps debugging where and why autosuspend is prevented.

Signed-off-by: Michał Mirosław <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/base/power/runtime.c

···
 	int retval;
 
 	if (rpmflags & RPM_GET_PUT) {
-		if (!atomic_dec_and_test(&dev->power.usage_count))
+		if (!atomic_dec_and_test(&dev->power.usage_count)) {
+			trace_rpm_usage_rcuidle(dev, rpmflags);
 			return 0;
+		}
 	}
 
 	might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
···
 	int retval;
 
 	if (rpmflags & RPM_GET_PUT) {
-		if (!atomic_dec_and_test(&dev->power.usage_count))
+		if (!atomic_dec_and_test(&dev->power.usage_count)) {
+			trace_rpm_usage_rcuidle(dev, rpmflags);
 			return 0;
+		}
 	}
 
 	might_sleep_if(!(rpmflags & RPM_ASYNC) && !dev->power.irq_safe);
···
 	retval = dev->power.disable_depth > 0 ? -EINVAL :
 		dev->power.runtime_status == RPM_ACTIVE
 			&& atomic_inc_not_zero(&dev->power.usage_count);
+	trace_rpm_usage_rcuidle(dev, 0);
 	spin_unlock_irqrestore(&dev->power.lock, flags);
 	return retval;
 }
···
 	dev->power.runtime_auto = true;
 	if (atomic_dec_and_test(&dev->power.usage_count))
 		rpm_idle(dev, RPM_AUTO | RPM_ASYNC);
+	else
+		trace_rpm_usage_rcuidle(dev, RPM_AUTO | RPM_ASYNC);
 
  out:
 	spin_unlock_irq(&dev->power.lock);
···
 		if (!old_use || old_delay >= 0) {
 			atomic_inc(&dev->power.usage_count);
 			rpm_resume(dev, 0);
+		} else {
+			trace_rpm_usage_rcuidle(dev, 0);
 		}
 	}
 

include/trace/events/rpm.h

···
 
 	TP_ARGS(dev, flags)
 );
+DEFINE_EVENT(rpm_internal, rpm_usage,
+
+	TP_PROTO(struct device *dev, int flags),
+
+	TP_ARGS(dev, flags)
+);
 
 TRACE_EVENT(rpm_return_int,
 	TP_PROTO(struct device *dev, unsigned long ip, int ret),