media: h264: Store current picture fields

This information, also called picture structure, is required in field
decoding mode to construct reference lists.

Signed-off-by: Nicolas Dufresne <[e-mail]>
Reviewed-by: Sebastian Fricke <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/v4l2-core/v4l2-h264.c

···
 	cur_frame_num = dec_params->frame_num;
 
 	memset(b, 0, sizeof(*b));
-	if (!(dec_params->flags & V4L2_H264_DECODE_PARAM_FLAG_FIELD_PIC))
+	if (!(dec_params->flags & V4L2_H264_DECODE_PARAM_FLAG_FIELD_PIC)) {
 		b->cur_pic_order_count = min(dec_params->bottom_field_order_cnt,
 					     dec_params->top_field_order_cnt);
-	else if (dec_params->flags & V4L2_H264_DECODE_PARAM_FLAG_BOTTOM_FIELD)
+		b->cur_pic_fields = V4L2_H264_FRAME_REF;
+	} else if (dec_params->flags & V4L2_H264_DECODE_PARAM_FLAG_BOTTOM_FIELD) {
 		b->cur_pic_order_count = dec_params->bottom_field_order_cnt;
-	else
+		b->cur_pic_fields = V4L2_H264_BOTTOM_FIELD_REF;
+	} else {
 		b->cur_pic_order_count = dec_params->top_field_order_cnt;
+		b->cur_pic_fields = V4L2_H264_TOP_FIELD_REF;
+	}
 
 	for (i = 0; i < V4L2_H264_NUM_DPB_ENTRIES; i++) {
 		u32 pic_order_count;

include/media/v4l2-h264.h

···
  * @refs.longterm: set to true for a long term reference
  * @refs: array of references
  * @cur_pic_order_count: picture order count of the frame being decoded
+ * @cur_pic_fields: fields present in the frame being decoded
  * @unordered_reflist: unordered list of references. Will be used to generate
  *		       ordered P/B0/B1 lists
  * @num_valid: number of valid references in the refs array
···
 		u32 pic_num;
 		u16 longterm : 1;
 	} refs[V4L2_H264_NUM_DPB_ENTRIES];
+
 	s32 cur_pic_order_count;
+	u8 cur_pic_fields;
+
 	struct v4l2_h264_reference unordered_reflist[V4L2_H264_REF_LIST_LEN];
 	u8 num_valid;
 };