[PATCH v9 16/20] coresight: Add PM callbacks for sink device

[Leo Yan]

Unlike a system level's sink, the per-CPU sink may lose power during CPU
idle states. Currently, this refers specifically to TRBE as the sink.

This commit invokes save and restore callbacks for the sink in the PM
notifier.

Tested-by: James Clark <james.clark at linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun at arm.com>
Reviewed-by: James Clark <james.clark at linaro.org>
Signed-off-by: Leo Yan <leo.yan at arm.com>
---
 drivers/hwtracing/coresight/coresight-core.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 7fafec04de3e8262b7ca66671c6de635b671ceba..a41e77da4f083d4b5d162e7b70905f22bddf7ca2 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -1757,11 +1757,17 @@ static bool coresight_pm_is_needed(struct coresight_path *path)
 
 static int coresight_pm_device_save(struct coresight_device *csdev)
 {
+	if (!csdev || !coresight_ops(csdev)->pm_save_disable)
+		return 0;
+
 	return coresight_ops(csdev)->pm_save_disable(csdev);
 }
 
 static void coresight_pm_device_restore(struct coresight_device *csdev)
 {
+	if (!csdev || !coresight_ops(csdev)->pm_restore_enable)
+		return;
+
 	coresight_ops(csdev)->pm_restore_enable(csdev);
 }
 
@@ -1780,20 +1786,35 @@ static int coresight_pm_save(struct coresight_path *path)
 	to = list_prev_entry(coresight_path_last_node(path), link);
 	coresight_disable_path_from_to(path, from, to);
 
+	ret = coresight_pm_device_save(coresight_get_sink(path));
+	if (ret)
+		goto failed_out;
+
 	return 0;
+
+failed_out:
+	coresight_enable_path_from_to(path, coresight_get_mode(source),
+				      from, to);
+	coresight_pm_device_restore(source);
+	return ret;
 }
 
 static void coresight_pm_restore(struct coresight_path *path)
 {
 	struct coresight_device *source = coresight_get_source(path);
+	struct coresight_device *sink = coresight_get_sink(path);
 	struct coresight_node *from, *to;
 
+	coresight_pm_device_restore(sink);
+
 	from = coresight_path_first_node(path);
 	/* Up to the node before sink to avoid latency */
 	to = list_prev_entry(coresight_path_last_node(path), link);
 	if (coresight_enable_path_from_to(path, coresight_get_mode(source),
-					  from, to))
+					  from, to)) {
+		coresight_pm_device_save(sink);
 		return;
+	}
 
 	coresight_pm_device_restore(source);
 }

-- 
2.34.1