media: uapi: h264: Update reference lists

When dealing with interlaced frames, reference lists must tell if
each particular reference is meant for top or bottom field. This info
is currently not provided at all in the H264 related controls.

Change reference lists to hold a structure, which specifies
an index into the DPB array and the field/frame specification
for the picture.

Currently the only user of these lists is Cedrus which is just compile
fixed here. Actual usage of will come in a following commit.
Signed-off-by: NJernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: NEzequiel Garcia <ezequiel@collabora.com>
Tested-by: NJonas Karlman <jonas@kwiboo.se>
Signed-off-by: NHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>

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

@@ -1843,10 +1843,10 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
     * - __u32
       - ``slice_group_change_cycle``
       -
-    * - __u8
+    * - struct :c:type:`v4l2_h264_reference`
       - ``ref_pic_list0[32]``
       - Reference picture list after applying the per-slice modifications
-    * - __u8
+    * - struct :c:type:`v4l2_h264_reference`
       - ``ref_pic_list1[32]``
       - Reference picture list after applying the per-slice modifications
     * - __u32
@@ -1926,6 +1926,46 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
       - ``chroma_offset[32][2]``
       -
 
+``Picture Reference``
+
+.. c:type:: v4l2_h264_reference
+
+.. cssclass:: longtable
+
+.. flat-table:: struct v4l2_h264_reference
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - __u8
+      - ``fields``
+      - Specifies how the picture is referenced. See :ref:`Reference Fields <h264_ref_fields>`
+    * - __u8
+      - ``index``
+      - Index into the :c:type:`v4l2_ctrl_h264_decode_params`.dpb array.
+
+.. _h264_ref_fields:
+
+``Reference Fields``
+
+.. cssclass:: longtable
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - ``V4L2_H264_TOP_FIELD_REF``
+      - 0x1
+      - The top field in field pair is used for short-term reference.
+    * - ``V4L2_H264_BOTTOM_FIELD_REF``
+      - 0x2
+      - The bottom field in field pair is used for short-term reference.
+    * - ``V4L2_H264_FRAME_REF``
+      - 0x3
+      - The frame (or the top/bottom fields, if it's a field pair)
+        is used for short-term reference.
+
 ``V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS (struct)``
     Specifies the decode parameters (as extracted from the bitstream)
     for the associated H264 slice data. This includes the necessary

drivers/staging/media/sunxi/cedrus/cedrus_h264.c

@@ -166,8 +166,8 @@ static void cedrus_write_frame_list(struct cedrus_ctx *ctx,
 
 static void _cedrus_write_ref_list(struct cedrus_ctx *ctx,
 				   struct cedrus_run *run,
-				   const u8 *ref_list, u8 num_ref,
-				   enum cedrus_h264_sram_off sram)
+				   const struct v4l2_h264_reference *ref_list,
+				   u8 num_ref, enum cedrus_h264_sram_off sram)
 {
 	const struct v4l2_ctrl_h264_decode_params *decode = run->h264.decode_params;
 	struct vb2_queue *cap_q;
@@ -188,7 +188,7 @@ static void _cedrus_write_ref_list(struct cedrus_ctx *ctx,
 		int buf_idx;
 		u8 dpb_idx;
 
-		dpb_idx = ref_list[i];
+		dpb_idx = ref_list[i].index;
 		dpb = &decode->dpb[dpb_idx];
 
 		if (!(dpb->flags & V4L2_H264_DPB_ENTRY_FLAG_ACTIVE))

include/media/h264-ctrls.h

@@ -19,6 +19,8 @@
  */
 #define V4L2_H264_NUM_DPB_ENTRIES 16
 
+#define V4L2_H264_REF_LIST_LEN (2 * V4L2_H264_NUM_DPB_ENTRIES)
+
 /* Our pixel format isn't stable at the moment */
 #define V4L2_PIX_FMT_H264_SLICE v4l2_fourcc('S', '2', '6', '4') /* H264 parsed slices */
 
@@ -140,6 +142,17 @@ struct v4l2_h264_pred_weight_table {
 #define V4L2_H264_SLICE_FLAG_DIRECT_SPATIAL_MV_PRED	0x04
 #define V4L2_H264_SLICE_FLAG_SP_FOR_SWITCH		0x08
 
+#define V4L2_H264_TOP_FIELD_REF				0x1
+#define V4L2_H264_BOTTOM_FIELD_REF			0x2
+#define V4L2_H264_FRAME_REF				0x3
+
+struct v4l2_h264_reference {
+	__u8 fields;
+
+	/* Index into v4l2_ctrl_h264_decode_params.dpb[] */
+	__u8 index;
+};
+
 struct v4l2_ctrl_h264_slice_params {
 	/* Size in bytes, including header */
 	__u32 size;
@@ -178,12 +191,8 @@ struct v4l2_ctrl_h264_slice_params {
 	__u8 num_ref_idx_l1_active_minus1;
 	__u32 slice_group_change_cycle;
 
-	/*
-	 * Entries on each list are indices into
-	 * v4l2_ctrl_h264_decode_params.dpb[].
-	 */
-	__u8 ref_pic_list0[32];
-	__u8 ref_pic_list1[32];
+	struct v4l2_h264_reference ref_pic_list0[V4L2_H264_REF_LIST_LEN];
+	struct v4l2_h264_reference ref_pic_list1[V4L2_H264_REF_LIST_LEN];
 
 	__u32 flags;
 };