[RFC PATCH 3/3] thermal: trace: Trace when temperature is above a trip point

[Punit Agrawal <punit.agrawal@arm.com>]

Create a new event to trace when the temperature is above a trip
point. Use the trace-point when handling non-critical and critical
trip pionts.

Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
---
Hi Steven,

I am facing an issue with partial trace being emitted when using
__print_symbolic in this patch. 

When the trip_type is THERMAL_TRIP_ACTIVE (i.e., the first value in
the symbol map), the emitted trace contains the corresponding string
("active"). But for other values of trip_type an empty string is
emitted in the trace.

I've looked at other uses of __print_symbolic in the kernel and don't
see any difference in usage. Do you know what could be causing this or
alternately have any pointers on how to debug this behaviour?

Thanks.
Punit

 drivers/thermal/fair_share.c   |    7 ++++++-
 drivers/thermal/step_wise.c    |    5 ++++-
 drivers/thermal/thermal_core.c |    2 ++
 include/trace/events/thermal.h |   30 ++++++++++++++++++++++++++++++
 4 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/drivers/thermal/fair_share.c b/drivers/thermal/fair_share.c
index 944ba2f..2cddd68 100644
--- a/drivers/thermal/fair_share.c
+++ b/drivers/thermal/fair_share.c
@@ -23,6 +23,7 @@
  */
 
 #include <linux/thermal.h>
+#include <trace/events/thermal.h>
 
 #include "thermal_core.h"
 
@@ -34,14 +35,18 @@ static int get_trip_level(struct thermal_zone_device *tz)
 {
 	int count = 0;
 	unsigned long trip_temp;
+	enum thermal_trip_type trip_type;
 
 	if (tz->trips == 0 || !tz->ops->get_trip_temp)
 		return 0;
 
 	for (count = 0; count < tz->trips; count++) {
 		tz->ops->get_trip_temp(tz, count, &trip_temp);
-		if (tz->temperature < trip_temp)
+		if (tz->temperature < trip_temp) {
+			tz->ops->get_trip_type(tz, count, &trip_type);
+			trace_thermal_zone_trip(tz, count, trip_type);
 			break;
+		}
 	}
 	return count;
 }
diff --git a/drivers/thermal/step_wise.c b/drivers/thermal/step_wise.c
index f251521..3b54c2c 100644
--- a/drivers/thermal/step_wise.c
+++ b/drivers/thermal/step_wise.c
@@ -23,6 +23,7 @@
  */
 
 #include <linux/thermal.h>
+#include <trace/events/thermal.h>
 
 #include "thermal_core.h"
 
@@ -129,8 +130,10 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
 
 	trend = get_tz_trend(tz, trip);
 
-	if (tz->temperature >= trip_temp)
+	if (tz->temperature >= trip_temp) {
 		throttle = true;
+		trace_thermal_zone_trip(tz, trip, trip_type);
+	}
 
 	dev_dbg(&tz->device, "Trip%d[type=%d,temp=%ld]:trend=%d,throttle=%d\n",
 				trip, trip_type, trip_temp, trend, throttle);
diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index c74c78d..454884a 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -371,6 +371,8 @@ static void handle_critical_trips(struct thermal_zone_device *tz,
 	if (tz->temperature < trip_temp)
 		return;
 
+	trace_thermal_zone_trip(tz, trip, trip_type);
+
 	if (tz->ops->notify)
 		tz->ops->notify(tz, trip, trip_type);
 
diff --git a/include/trace/events/thermal.h b/include/trace/events/thermal.h
index 894a79e..5eeb1e7 100644
--- a/include/trace/events/thermal.h
+++ b/include/trace/events/thermal.h
@@ -51,6 +51,36 @@ TRACE_EVENT(cdev_update,
 	TP_printk("type=%s target=%lu", __get_str(type), __entry->target)
 );
 
+TRACE_EVENT(thermal_zone_trip,
+
+	TP_PROTO(struct thermal_zone_device *tz, int trip,
+		enum thermal_trip_type trip_type),
+
+	TP_ARGS(tz, trip, trip_type),
+
+	TP_STRUCT__entry(
+		__string(thermal_zone, tz->type)
+		__field(int, id)
+		__field(int, trip)
+		__field(enum thermal_trip_type, trip_type)
+	),
+
+	TP_fast_assign(
+		__assign_str(thermal_zone, tz->type);
+		__entry->id = tz->id;
+		__entry->trip = trip;
+		__entry->trip_type = trip_type;
+	),
+
+	TP_printk("thermal_zone=%s id=%d trip=%d trip_type=%s",
+		__get_str(thermal_zone), __entry->id, __entry->trip,
+		__print_symbolic(__entry->trip_type,
+				{ THERMAL_TRIP_ACTIVE, "active" },
+				{ THERMAL_TRIP_PASSIVE, "passive" },
+				{ THERMAL_TRIP_HOT, "hot" },
+				{ THERMAL_TRIP_CRITICAL, "critical" }))
+);
+
 #endif /* _TRACE_THERMAL_H */
 
 /* This part must be outside protection */
-- 
1.7.10.4