[media] uvcvideo: Add VIDIOC_[GS]_PRIORITY support

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/usb/uvc/uvc_driver.c

@@ -1562,6 +1562,7 @@ static int uvc_scan_device(struct uvc_device *dev)
 		INIT_LIST_HEAD(&chain->entities);
 		mutex_init(&chain->ctrl_mutex);
 		chain->dev = dev;
+		v4l2_prio_init(&chain->prio);
 
 		if (uvc_scan_chain(chain, term) < 0) {
 			kfree(chain);
@@ -1722,6 +1723,8 @@ static int uvc_register_video(struct uvc_device *dev,
 	vdev->v4l2_dev = &dev->vdev;
 	vdev->fops = &uvc_fops;
 	vdev->release = uvc_release;
+	vdev->prio = &stream->chain->prio;
+	set_bit(V4L2_FL_USE_FH_PRIO, &vdev->flags);
 	if (stream->type == V4L2_BUF_TYPE_VIDEO_OUTPUT)
 		vdev->vfl_dir = VFL_DIR_TX;
 	strlcpy(vdev->name, dev->name, sizeof vdev->name);

drivers/media/usb/uvc/uvc_v4l2.c

@@ -576,6 +576,19 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		break;
 	}
 
+	/* Priority */
+	case VIDIOC_G_PRIORITY:
+		*(u32 *)arg = v4l2_prio_max(vdev->prio);
+		break;
+
+	case VIDIOC_S_PRIORITY:
+		ret = v4l2_prio_check(vdev->prio, handle->vfh.prio);
+		if (ret < 0)
+			return ret;
+
+		return v4l2_prio_change(vdev->prio, &handle->vfh.prio,
+					*(u32 *)arg);
+
 	/* Get, Set & Query control */
 	case VIDIOC_QUERYCTRL:
 		return uvc_query_v4l2_ctrl(chain, arg);
@@ -606,6 +619,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		struct v4l2_control *ctrl = arg;
 		struct v4l2_ext_control xctrl;
 
+		ret = v4l2_prio_check(vdev->prio, handle->vfh.prio);
+		if (ret < 0)
+			return ret;
+
 		memset(&xctrl, 0, sizeof xctrl);
 		xctrl.id = ctrl->id;
 		xctrl.value = ctrl->value;
@@ -653,6 +670,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	}
 
 	case VIDIOC_S_EXT_CTRLS:
+		ret = v4l2_prio_check(vdev->prio, handle->vfh.prio);
+		if (ret < 0)
+			return ret;
+		/* Fall through */
 	case VIDIOC_TRY_EXT_CTRLS:
 	{
 		struct v4l2_ext_controls *ctrls = arg;
@@ -747,6 +768,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	{
 		u32 input = *(u32 *)arg + 1;
 
+		ret = v4l2_prio_check(vdev->prio, handle->vfh.prio);
+		if (ret < 0)
+			return ret;
+
 		if ((ret = uvc_acquire_privileges(handle)) < 0)
 			return ret;
 
@@ -800,6 +825,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	}
 
 	case VIDIOC_S_FMT:
+		ret = v4l2_prio_check(vdev->prio, handle->vfh.prio);
+		if (ret < 0)
+			return ret;
+
 		if ((ret = uvc_acquire_privileges(handle)) < 0)
 			return ret;
 
@@ -902,6 +931,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		return uvc_v4l2_get_streamparm(stream, arg);
 
 	case VIDIOC_S_PARM:
+		ret = v4l2_prio_check(vdev->prio, handle->vfh.prio);
+		if (ret < 0)
+			return ret;
+
 		if ((ret = uvc_acquire_privileges(handle)) < 0)
 			return ret;
 
@@ -936,6 +969,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 
 	/* Buffers & streaming */
 	case VIDIOC_REQBUFS:
+		ret = v4l2_prio_check(vdev->prio, handle->vfh.prio);
+		if (ret < 0)
+			return ret;
+
 		if ((ret = uvc_acquire_privileges(handle)) < 0)
 			return ret;
 
@@ -981,6 +1018,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		if (*type != stream->type)
 			return -EINVAL;
 
+		ret = v4l2_prio_check(vdev->prio, handle->vfh.prio);
+		if (ret < 0)
+			return ret;
+
 		if (!uvc_has_privileges(handle))
 			return -EBUSY;
 
@@ -999,6 +1040,10 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 		if (*type != stream->type)
 			return -EINVAL;
 
+		ret = v4l2_prio_check(vdev->prio, handle->vfh.prio);
+		if (ret < 0)
+			return ret;
+
 		if (!uvc_has_privileges(handle))
 			return -EBUSY;
 

drivers/media/usb/uvc/uvcvideo.h

@@ -372,6 +372,7 @@ struct uvc_video_chain {
 
 	struct mutex ctrl_mutex;		/* Protects ctrl.info */
 
+	struct v4l2_prio_state prio;		/* V4L2 priority state */
 	u32 caps;				/* V4L2 chain-wide caps */
 };