media: uapi: Add V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS control

The number of 'entry point offset' can be very variable.
Instead of using a large static array define a v4l2 dynamic array
of U32 (V4L2_CTRL_TYPE_U32).
The number of entry point offsets is reported by the elems field
and in struct v4l2_ctrl_hevc_slice_params.num_entry_point_offsets
field.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Acked-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Tested-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst

@@ -3010,6 +3010,11 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
     * - __u32
       - ``data_bit_offset``
       - Offset (in bits) to the video data in the current slice data.
+    * - __u32
+      - ``num_entry_point_offsets``
+      - Specifies the number of entry point offset syntax elements in the slice header.
+        When the driver supports it, the ``V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS``
+        must be set.
     * - __u8
       - ``nal_unit_type``
       - Specifies the coding type of the slice (B, P or I).
@@ -3150,6 +3155,17 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
 
     \normalsize
 
+``V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS (integer)``
+    Specifies entry point offsets in bytes.
+    This control is a dynamically sized array. The number of entry point
+    offsets is reported by the ``elems`` field.
+    This bitstream parameter is defined according to :ref:`hevc`.
+    They are described in section 7.4.7.1 "General slice segment header
+    semantics" of the specification.
+    When multiple slices are submitted in a request, the length of
+    this array must be the sum of num_entry_point_offsets of all the
+    slices in the request.
+
 ``V4L2_CID_STATELESS_HEVC_SCALING_MATRIX (struct)``
     Specifies the HEVC scaling matrix parameters used for the scaling process
     for transform coefficients.

drivers/media/v4l2-core/v4l2-ctrls-defs.c

@@ -1188,6 +1188,7 @@ const char *v4l2_ctrl_get_name(u32 id)
 	case V4L2_CID_STATELESS_HEVC_DECODE_PARAMS:		return "HEVC Decode Parameters";
 	case V4L2_CID_STATELESS_HEVC_DECODE_MODE:		return "HEVC Decode Mode";
 	case V4L2_CID_STATELESS_HEVC_START_CODE:		return "HEVC Start Code";
+	case V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS:	return "HEVC Entry Point Offsets";
 
 	/* Colorimetry controls */
 	/* Keep the order of the 'case's the same as in v4l2-controls.h! */
@@ -1518,6 +1519,10 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
 	case V4L2_CID_STATELESS_HEVC_DECODE_PARAMS:
 		*type = V4L2_CTRL_TYPE_HEVC_DECODE_PARAMS;
 		break;
+	case V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS:
+		*type = V4L2_CTRL_TYPE_U32;
+		*flags |= V4L2_CTRL_FLAG_DYNAMIC_ARRAY;
+		break;
 	case V4L2_CID_STATELESS_VP9_COMPRESSED_HDR:
 		*type = V4L2_CTRL_TYPE_VP9_COMPRESSED_HDR;
 		break;

include/media/hevc-ctrls.h

@@ -23,6 +23,7 @@
 #define V4L2_CID_STATELESS_HEVC_DECODE_PARAMS	(V4L2_CID_CODEC_BASE + 1012)
 #define V4L2_CID_STATELESS_HEVC_DECODE_MODE	(V4L2_CID_CODEC_BASE + 1015)
 #define V4L2_CID_STATELESS_HEVC_START_CODE	(V4L2_CID_CODEC_BASE + 1016)
+#define V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS (V4L2_CID_CODEC_BASE + 1017)
 
 /* enum v4l2_ctrl_type type values */
 #define V4L2_CTRL_TYPE_HEVC_SPS 0x0120
@@ -319,6 +320,8 @@ struct v4l2_hevc_pred_weight_table {
  *
  * @bit_size: size (in bits) of the current slice data
  * @data_bit_offset: offset (in bits) to the video data in the current slice data
+ * @num_entry_point_offsets: specifies the number of entry point offset syntax
+ *			     elements in the slice header.
  * @nal_unit_type: specifies the coding type of the slice (B, P or I)
  * @nuh_temporal_id_plus1: minus 1 specifies a temporal identifier for the NAL unit
  * @slice_type: see V4L2_HEVC_SLICE_TYPE_{}
@@ -361,7 +364,7 @@ struct v4l2_hevc_pred_weight_table {
 struct v4l2_ctrl_hevc_slice_params {
 	__u32	bit_size;
 	__u32	data_bit_offset;
-
+	__u32	num_entry_point_offsets;
 	/* ISO/IEC 23008-2, ITU-T Rec. H.265: NAL unit header */
 	__u8	nal_unit_type;
 	__u8	nuh_temporal_id_plus1;