[PATCH v7 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 registers save and restore callbacks for the sink via 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 | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index b888a31ca6abffe62e2264574a6d61b43184f600..e0784e8eecedae5a5121c03d6bb29f6a3ab5026f 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -1813,11 +1813,17 @@ 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);
 }
 
@@ -1839,7 +1845,17 @@ 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)
@@ -1847,6 +1863,8 @@ static void coresight_pm_restore(struct coresight_path *path)
 	struct coresight_device *source;
 	struct coresight_node *from, *to;
 
+	coresight_pm_device_restore(coresight_get_sink(path));
+
 	source = coresight_get_source(path);
 	from = coresight_path_first_node(path);
 	/* Up to the node before sink to avoid latency */

-- 
2.34.1