[media] v4l: Define video buffer flag for the COPY timestamp type

Define video buffer flag for the COPY timestamp. In this case the timestamp
value is copied from the OUTPUT to the corresponding CAPTURE buffer.

Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Documentation/DocBook/media/v4l/io.xml

@@ -1145,6 +1145,12 @@ in which case caches have not been used.</entry>
 	    same clock outside V4L2, use
 	    <function>clock_gettime(2)</function> .</entry>
 	  </row>
+	  <row>
+	    <entry><constant>V4L2_BUF_FLAG_TIMESTAMP_COPY</constant></entry>
+	    <entry>0x4000</entry>
+	    <entry>The CAPTURE buffer timestamp has been taken from the
+	    corresponding OUTPUT buffer. This flag applies only to mem2mem devices.</entry>
+	  </row>
 	</tbody>
       </tgroup>
     </table>

include/uapi/linux/videodev2.h

@@ -705,6 +705,7 @@ struct v4l2_buffer {
 #define V4L2_BUF_FLAG_TIMESTAMP_MASK		0xe000
 #define V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN		0x0000
 #define V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC	0x2000
+#define V4L2_BUF_FLAG_TIMESTAMP_COPY		0x4000
 
 /**
  * struct v4l2_exportbuffer - export of video buffer as DMABUF file descriptor