1 files changed, 41 insertions, 2 deletions

diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 7f2b478a048f..3e07fd335f8c 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -425,6 +425,42 @@ struct coresight_device *coresight_get_enabled_sink(bool deactivate)
 	return dev ? to_coresight_device(dev) : NULL;
 }
 
+/*
+ * coresight_grab_device - Power up this device and any of the helper
+ * devices connected to it for trace operation. Since the helper devices
+ * don't appear on the trace path, they should be handled along with the
+ * the master device.
+ */
+static void coresight_grab_device(struct coresight_device *csdev)
+{
+	int i;
+
+	for (i = 0; i < csdev->nr_outport; i++) {
+		struct coresight_device *child = csdev->conns[i].child_dev;
+
+		if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
+			pm_runtime_get_sync(child->dev.parent);
+	}
+	pm_runtime_get_sync(csdev->dev.parent);
+}
+
+/*
+ * coresight_drop_device - Release this device and any of the helper
+ * devices connected to it.
+ */
+static void coresight_drop_device(struct coresight_device *csdev)
+{
+	int i;
+
+	pm_runtime_put(csdev->dev.parent);
+	for (i = 0; i < csdev->nr_outport; i++) {
+		struct coresight_device *child = csdev->conns[i].child_dev;
+
+		if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
+			pm_runtime_put(child->dev.parent);
+	}
+}
+
 /**
  * _coresight_build_path - recursively build a path from a @csdev to a sink.
  * @csdev:	The device to start from.
@@ -473,9 +509,9 @@ out:
 	if (!node)
 		return -ENOMEM;
 
+	coresight_grab_device(csdev);
 	node->csdev = csdev;
 	list_add(&node->link, path);
-	pm_runtime_get_sync(csdev->dev.parent);
 
 	return 0;
 }
@@ -519,7 +555,7 @@ void coresight_release_path(struct list_head *path)
 	list_for_each_entry_safe(nd, next, path, link) {
 		csdev = nd->csdev;
 
-		pm_runtime_put_sync(csdev->dev.parent);
+		coresight_drop_device(csdev);
 		list_del(&nd->link);
 		kfree(nd);
 	}
@@ -770,6 +806,9 @@ static struct device_type coresight_dev_type[] = {
 		.name = "source",
 		.groups = coresight_source_groups,
 	},
+	{
+		.name = "helper",
+	},
 };
 
 static void coresight_device_release(struct device *dev)