media: staging: rkisp1: cap: serialize start/stop stream

In order to support simultaneous streaming from both capture devices,
start/stop vb2 calls need to be serialized to allow multiple concurrent
calls.
Signed-off-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/rkisp1/rkisp1-capture.c

@@ -880,6 +880,8 @@ static void rkisp1_vb2_stop_streaming(struct vb2_queue *queue)
 	struct rkisp1_device *rkisp1 = cap->rkisp1;
 	int ret;
 
+	mutex_lock(&cap->rkisp1->stream_lock);
+
 	rkisp1_stream_stop(cap);
 	media_pipeline_stop(&node->vdev.entity);
 	ret = rkisp1_pipeline_sink_walk(&node->vdev.entity, NULL,
@@ -896,6 +898,8 @@ static void rkisp1_vb2_stop_streaming(struct vb2_queue *queue)
 		dev_err(rkisp1->dev, "power down failed error:%d\n", ret);
 
 	rkisp1_dummy_buf_destroy(cap);
+
+	mutex_unlock(&cap->rkisp1->stream_lock);
 }
 
 /*
@@ -940,6 +944,8 @@ rkisp1_vb2_start_streaming(struct vb2_queue *queue, unsigned int count)
 	struct media_entity *entity = &cap->vnode.vdev.entity;
 	int ret;
 
+	mutex_lock(&cap->rkisp1->stream_lock);
+
 	ret = rkisp1_dummy_buf_create(cap);
 	if (ret)
 		goto err_ret_buffers;
@@ -969,6 +975,8 @@ rkisp1_vb2_start_streaming(struct vb2_queue *queue, unsigned int count)
 		goto err_pipe_disable;
 	}
 
+	mutex_unlock(&cap->rkisp1->stream_lock);
+
 	return 0;
 
 err_pipe_disable:
@@ -982,6 +990,7 @@ rkisp1_vb2_start_streaming(struct vb2_queue *queue, unsigned int count)
 	rkisp1_dummy_buf_destroy(cap);
 err_ret_buffers:
 	rkisp1_return_all_buffers(cap, VB2_BUF_STATE_QUEUED);
+	mutex_unlock(&cap->rkisp1->stream_lock);
 
 	return ret;
 }

drivers/staging/media/rkisp1/rkisp1-common.h

@@ -240,6 +240,7 @@ struct rkisp1_debug {
  * @rkisp1_capture: capture video device
  * @stats: ISP statistics output device
  * @params: ISP input parameters device
+ * @stream_lock: lock to serialize start/stop streaming in capture devices.
  */
 struct rkisp1_device {
 	void __iomem *base_addr;
@@ -259,6 +260,7 @@ struct rkisp1_device {
 	struct rkisp1_params params;
 	struct media_pipeline pipe;
 	struct vb2_alloc_ctx *alloc_ctx;
+	struct mutex stream_lock;
 	struct rkisp1_debug debug;
 };
 

drivers/staging/media/rkisp1/rkisp1-dev.c

@@ -472,6 +472,8 @@ static int rkisp1_probe(struct platform_device *pdev)
 	dev_set_drvdata(dev, rkisp1);
 	rkisp1->dev = dev;
 
+	mutex_init(&rkisp1->stream_lock);
+
 	rkisp1->base_addr = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(rkisp1->base_addr))
 		return PTR_ERR(rkisp1->base_addr);