[media] v4l: omap4iss: Stop started entities when pipeline start fails

If an entity can't be started when starting a pipeline we need to clean
up by stopping all entities that have been successfully started.
Otherwise the hardware and software states won't match, potentially
leading to crashes (for instance due to the CSI2 receiver receiving
interrupts with a NULL pipeline pointer).
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/staging/media/omap4iss/iss.c

@@ -559,6 +559,61 @@ static int iss_pipeline_link_notify(struct media_link *link, u32 flags,
  * Pipeline stream management
  */
 
+/*
+ * iss_pipeline_disable - Disable streaming on a pipeline
+ * @pipe: ISS pipeline
+ * @until: entity at which to stop pipeline walk
+ *
+ * Walk the entities chain starting at the pipeline output video node and stop
+ * all modules in the chain. Wait synchronously for the modules to be stopped if
+ * necessary.
+ *
+ * If the until argument isn't NULL, stop the pipeline walk when reaching the
+ * until entity. This is used to disable a partially started pipeline due to a
+ * subdev start error.
+ */
+static int iss_pipeline_disable(struct iss_pipeline *pipe,
+				struct media_entity *until)
+{
+	struct iss_device *iss = pipe->output->iss;
+	struct media_entity *entity;
+	struct media_pad *pad;
+	struct v4l2_subdev *subdev;
+	int failure = 0;
+	int ret;
+
+	entity = &pipe->output->video.entity;
+	while (1) {
+		pad = &entity->pads[0];
+		if (!(pad->flags & MEDIA_PAD_FL_SINK))
+			break;
+
+		pad = media_entity_remote_pad(pad);
+		if (pad == NULL ||
+		    media_entity_type(pad->entity) != MEDIA_ENT_T_V4L2_SUBDEV)
+			break;
+
+		entity = pad->entity;
+		if (entity == until)
+			break;
+
+		subdev = media_entity_to_v4l2_subdev(entity);
+		ret = v4l2_subdev_call(subdev, video, s_stream, 0);
+		if (ret < 0) {
+			dev_dbg(iss->dev, "%s: module stop timeout.\n",
+				subdev->name);
+			/* If the entity failed to stopped, assume it has
+			 * crashed. Mark it as such, the ISS will be reset when
+			 * applications will release it.
+			 */
+			iss->crashed |= 1U << subdev->entity.id;
+			failure = -ETIMEDOUT;
+		}
+	}
+
+	return failure;
+}
+
 /*
  * iss_pipeline_enable - Enable streaming on a pipeline
  * @pipe: ISS pipeline
@@ -610,8 +665,10 @@ static int iss_pipeline_enable(struct iss_pipeline *pipe,
 		subdev = media_entity_to_v4l2_subdev(entity);
 
 		ret = v4l2_subdev_call(subdev, video, s_stream, mode);
-		if (ret < 0 && ret != -ENOIOCTLCMD)
+		if (ret < 0 && ret != -ENOIOCTLCMD) {
+			iss_pipeline_disable(pipe, entity);
 			return ret;
+		}
 
 		if (subdev == &iss->csi2a.subdev ||
 		    subdev == &iss->csi2b.subdev)
@@ -622,53 +679,6 @@ static int iss_pipeline_enable(struct iss_pipeline *pipe,
 	return 0;
 }
 
-/*
- * iss_pipeline_disable - Disable streaming on a pipeline
- * @pipe: ISS pipeline
- *
- * Walk the entities chain starting at the pipeline output video node and stop
- * all modules in the chain. Wait synchronously for the modules to be stopped if
- * necessary.
- */
-static int iss_pipeline_disable(struct iss_pipeline *pipe)
-{
-	struct iss_device *iss = pipe->output->iss;
-	struct media_entity *entity;
-	struct media_pad *pad;
-	struct v4l2_subdev *subdev;
-	int failure = 0;
-	int ret;
-
-	entity = &pipe->output->video.entity;
-	while (1) {
-		pad = &entity->pads[0];
-		if (!(pad->flags & MEDIA_PAD_FL_SINK))
-			break;
-
-		pad = media_entity_remote_pad(pad);
-		if (pad == NULL ||
-		    media_entity_type(pad->entity) != MEDIA_ENT_T_V4L2_SUBDEV)
-			break;
-
-		entity = pad->entity;
-		subdev = media_entity_to_v4l2_subdev(entity);
-
-		ret = v4l2_subdev_call(subdev, video, s_stream, 0);
-		if (ret < 0) {
-			dev_dbg(iss->dev, "%s: module stop timeout.\n",
-				subdev->name);
-			/* If the entity failed to stopped, assume it has
-			 * crashed. Mark it as such, the ISS will be reset when
-			 * applications will release it.
-			 */
-			iss->crashed |= 1U << subdev->entity.id;
-			failure = -ETIMEDOUT;
-		}
-	}
-
-	return failure;
-}
-
 /*
  * omap4iss_pipeline_set_stream - Enable/disable streaming on a pipeline
  * @pipe: ISS pipeline
@@ -687,7 +697,7 @@ int omap4iss_pipeline_set_stream(struct iss_pipeline *pipe,
 	int ret;
 
 	if (state == ISS_PIPELINE_STREAM_STOPPED)
-		ret = iss_pipeline_disable(pipe);
+		ret = iss_pipeline_disable(pipe, NULL);
 	else
 		ret = iss_pipeline_enable(pipe, state);