PM / sleep: trace events for device PM callbacks

Adds two trace events which supply the same info that initcall_debug
provides, but via ftrace instead of dmesg. The existing initcall_debug
calls require the pm_print_times_enabled var to be set (either via
sysfs or via the kernel cmd line). The new trace events provide all the
same info as the initcall_debug prints but with less overhead, and also
with coverage of device prepare and complete device callbacks.

These events replace the device_pm_report_time event (which has been
removed). device_pm_callback_start is called first and provides the device
and callback info. device_pm_callback_end is called after with the
device name and error info. The time and pid are gathered from the trace
data headers.

Signed-off-by: Todd Brandt <todd.e.brandt@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index de3fe4fe350a..bf412961a934 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -214,9 +214,6 @@ static void initcall_debug_report(struct device *dev, ktime_t calltime,
 		pr_info("call %s+ returned %d after %Ld usecs\n", dev_name(dev),
 			error, (unsigned long long)nsecs >> 10);
 	}
-
-	trace_device_pm_report_time(dev, info, nsecs, pm_verb(state.event),
-				    error);
 }
 
 /**
@@ -387,7 +384,9 @@ static int dpm_run_callback(pm_callback_t cb, struct device *dev,
 	calltime = initcall_debug_start(dev);
 
 	pm_dev_dbg(dev, state, info);
+	trace_device_pm_callback_start(dev, info, state.event);
 	error = cb(dev);
+	trace_device_pm_callback_end(dev, error);
 	suspend_report_result(cb, error);
 
 	initcall_debug_report(dev, calltime, error, state, info);
@@ -919,7 +918,9 @@ static void device_complete(struct device *dev, pm_message_t state)
 
 	if (callback) {
 		pm_dev_dbg(dev, state, info);
+		trace_device_pm_callback_start(dev, info, state.event);
 		callback(dev);
+		trace_device_pm_callback_end(dev, 0);
 	}
 
 	device_unlock(dev);
@@ -1307,7 +1308,9 @@ static int legacy_suspend(struct device *dev, pm_message_t state,
 
 	calltime = initcall_debug_start(dev);
 
+	trace_device_pm_callback_start(dev, info, state.event);
 	error = cb(dev, state);
+	trace_device_pm_callback_end(dev, error);
 	suspend_report_result(cb, error);
 
 	initcall_debug_report(dev, calltime, error, state, info);
@@ -1563,8 +1566,11 @@ static int device_prepare(struct device *dev, pm_message_t state)
 		callback = dev->driver->pm->prepare;
 	}
 
-	if (callback)
+	if (callback) {
+		trace_device_pm_callback_start(dev, info, state.event);
 		ret = callback(dev);
+		trace_device_pm_callback_end(dev, ret);
+	}
 
 	device_unlock(dev);