Merge pull request #76 from toradex/4.9-2.3.x-imx

4.9 2.3.x imx

1 files changed, 15 insertions, 7 deletions

diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 398e44a9ec45..5ffabc388630 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -132,12 +132,14 @@ static int coresight_enable_sink(struct coresight_device *csdev, u32 mode)
 {
 	int ret;
 
-	if (!csdev->enable) {
-		if (sink_ops(csdev)->enable) {
-			ret = sink_ops(csdev)->enable(csdev, mode);
-			if (ret)
-				return ret;
-		}
+	/*
+	 * We need to make sure the "new" session is compatible with the
+	 * existing "mode" of operation.
+	 */
+	if (sink_ops(csdev)->enable) {
+		ret = sink_ops(csdev)->enable(csdev, mode);
+		if (ret)
+			return ret;
 		csdev->enable = true;
 	}
 
@@ -331,8 +333,14 @@ int coresight_enable_path(struct list_head *path, u32 mode)
 		switch (type) {
 		case CORESIGHT_DEV_TYPE_SINK:
 			ret = coresight_enable_sink(csdev, mode);
+			/*
+			 * Sink is the first component turned on. If we
+			 * failed to enable the sink, there are no components
+			 * that need disabling. Disabling the path here
+			 * would mean we could disrupt an existing session.
+			 */
 			if (ret)
-				goto err;
+				goto out;
 			break;
 		case CORESIGHT_DEV_TYPE_SOURCE:
 			/* sources are enabled from either sysFS or Perf */