media: atomisp: Call media_pipeline_alloc_start() in stream start

Call media_pipeline_alloc_start() from atomisp_start_streaming() to mark
all involved subdevs as busy so that the links cannot be changed through
the media-controller APIs while streaming.

Reviewed-by: Andy Shevchenko <[e-mail]>
Signed-off-by: Hans de Goede <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/staging/media/atomisp/pci/atomisp_ioctl.c

···
 	if (ret)
 		goto out_unlock;
 
+	/*
+	 * When running a classic v4l2 app after a media-controller aware
+	 * app, the CSI-receiver -> ISP link for the current sensor may be
+	 * disabled. Fix this up before marking the pipeline as started.
+	 */
+	mutex_lock(&isp->media_dev.graph_mutex);
+	atomisp_setup_input_links(isp);
+	ret = __media_pipeline_start(&asd->video_out.vdev.entity.pads[0], &asd->video_out.pipe);
+	mutex_unlock(&isp->media_dev.graph_mutex);
+	if (ret) {
+		dev_err(isp->dev, "Error starting mc pipline: %d\n", ret);
+		goto out_unlock;
+	}
+
 	/* Input system HW workaround */
 	atomisp_dma_burst_len_cfg(asd);
 
···
 	if (ret)
 		dev_warn(isp->dev, "Recreating streams failed: %d\n", ret);
 
+	media_pipeline_stop(&asd->video_out.vdev.entity.pads[0]);
 	mutex_unlock(&isp->mutex);
 }
 

drivers/staging/media/atomisp/pci/atomisp_subdev.h

···
 	struct video_device vdev;
 	enum v4l2_buf_type type;
 	struct media_pad pad;
+	struct media_pipeline pipe;
 	struct vb2_queue vb_queue;
 	/* Lock for vb_queue, when also taking isp->mutex this must be taken first! */
 	struct mutex vb_queue_mutex;