[PATCH v6 15/19] 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>
Signed-off-by: Leo Yan <leo.yan at arm.com>
---
 drivers/hwtracing/coresight/coresight-core.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 8763ca1d81674efa3dea9479a6a6c4025b652559..25ed45129375d83adb2e1b30664aef15535e8164 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -1727,6 +1727,22 @@ static bool coresight_pm_is_needed(struct coresight_device *csdev)
 	return coresight_ops(csdev)->pm_is_needed(csdev);
 }
 
+static int coresight_pm_sink_save(struct coresight_device *sink)
+{
+	if (!sink || !coresight_ops(sink)->pm_save_disable)
+		return 0;
+
+	return coresight_ops(sink)->pm_save_disable(sink);
+}
+
+static void coresight_pm_sink_restore(struct coresight_device *sink)
+{
+	if (!sink || !coresight_ops(sink)->pm_restore_enable)
+		return;
+
+	coresight_ops(sink)->pm_restore_enable(sink);
+}
+
 static int coresight_pm_save(struct coresight_device *csdev)
 {
 	int ret;
@@ -1745,7 +1761,18 @@ static int coresight_pm_save(struct coresight_device *csdev)
 
 	coresight_disable_helpers(csdev, csdev->path);
 	coresight_disable_path(csdev->path);
+
+	ret = coresight_pm_sink_save(coresight_get_sink(csdev->path));
+	if (ret)
+		goto failed_out;
+
 	return 0;
+
+failed_out:
+	coresight_enable_path(csdev->path, coresight_get_mode(csdev));
+	coresight_ops(csdev)->pm_restore_enable(csdev);
+	csdev->path->in_idle = false;
+	return ret;
 }
 
 static void coresight_pm_restore(struct coresight_device *csdev)
@@ -1753,6 +1780,7 @@ static void coresight_pm_restore(struct coresight_device *csdev)
 	if (WARN_ON(!csdev->path))
 		return;
 
+	coresight_pm_sink_restore(coresight_get_sink(csdev->path));
 	coresight_enable_path(csdev->path, coresight_get_mode(csdev));
 	coresight_ops(csdev)->pm_restore_enable(csdev);
 	csdev->path->in_idle = false;

-- 
2.34.1