4 files changed, 79 insertions, 3 deletions

diff --git a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
index c5f39dd50043..1da17a2c94d7 100644
--- a/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
+++ b/Documentation/media/uapi/v4l/ext-ctrls-codec.rst
@@ -1748,6 +1748,14 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
       - ``size``
       -
     * - __u32
+      - ``start_byte_offset``
+        Offset (in bytes) from the beginning of the OUTPUT buffer to the start
+        of the slice. If the slice starts with a start code, then this is the
+        offset to such start code. When operating in slice-based decoding mode
+        (see :c:type:`v4l2_mpeg_video_h264_decode_mode`), this field should
+        be set to 0. When operating in frame-based decoding mode, this field
+        should be 0 for the first slice.
+    * - __u32
       - ``header_bit_size``
       -
     * - __u16
@@ -1930,7 +1938,10 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
       -
     * - __u16
       - ``num_slices``
-      - Number of slices needed to decode the current frame
+      - Number of slices needed to decode the current frame/field. When
+        operating in slice-based decoding mode (see
+        :c:type:`v4l2_mpeg_video_h264_decode_mode`), this field
+        should always be set to one.
     * - __u16
       - ``nal_ref_idc``
       - NAL reference ID value coming from the NAL Unit header
@@ -2021,6 +2032,50 @@ enum v4l2_mpeg_video_h264_hierarchical_coding_type -
       - 0x00000004
       - The DPB entry is a long term reference frame
 
+``V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE (enum)``
+    Specifies the decoding mode to use. Currently exposes slice-based and
+    frame-based decoding but new modes might be added later on.
+    This control is used as a modifier for V4L2_PIX_FMT_H264_SLICE
+    pixel format. Applications that support V4L2_PIX_FMT_H264_SLICE
+    are required to set this control in order to specify the decoding mode
+    that is expected for the buffer.
+    Drivers may expose a single or multiple decoding modes, depending
+    on what they can support.
+
+    .. note::
+
+       This menu control is not yet part of the public kernel API and
+       it is expected to change.
+
+.. c:type:: v4l2_mpeg_video_h264_decode_mode
+
+.. cssclass:: longtable
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - ``V4L2_MPEG_VIDEO_H264_DECODE_MODE_SLICE_BASED``
+      - 0
+      - Decoding is done at the slice granularity.
+        In this mode, ``num_slices`` field in struct
+        :c:type:`v4l2_ctrl_h264_decode_params` should be set to 1,
+        and ``start_byte_offset`` in struct
+        :c:type:`v4l2_ctrl_h264_slice_params` should be set to 0.
+        The OUTPUT buffer must contain a single slice.
+    * - ``V4L2_MPEG_VIDEO_H264_DECODE_MODE_FRAME_BASED``
+      - 1
+      - Decoding is done at the frame granularity.
+        In this mode, ``num_slices`` field in struct
+        :c:type:`v4l2_ctrl_h264_decode_params` should be set to the number
+        of slices in the frame, and ``start_byte_offset`` in struct
+        :c:type:`v4l2_ctrl_h264_slice_params` should be set accordingly
+        for each slice. For the first slice, ``start_byte_offset`` should
+        be zero.
+        The OUTPUT buffer must contain all slices needed to decode the
+        frame. The OUTPUT buffer must also contain both fields.
+
 .. _v4l2-mpeg-mpeg2:
 
 ``V4L2_CID_MPEG_VIDEO_MPEG2_SLICE_PARAMS (struct)``
diff --git a/Documentation/media/uapi/v4l/pixfmt-compressed.rst b/Documentation/media/uapi/v4l/pixfmt-compressed.rst
index 9b65473a2288..d666eb51741a 100644
--- a/Documentation/media/uapi/v4l/pixfmt-compressed.rst
+++ b/Documentation/media/uapi/v4l/pixfmt-compressed.rst
@@ -60,8 +60,10 @@ Compressed Formats
         extracted from the H264 bitstream.  This format is adapted for
         stateless video decoders that implement an H264 pipeline
         (using the :ref:`mem2mem` and :ref:`media-request-api`).
-        Metadata associated with the frame to decode are required to
-        be passed through the ``V4L2_CID_MPEG_VIDEO_H264_SPS``,
+        This pixelformat has a modifier that must be set at least once
+        through the ``V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE`` control.
+        In addition, metadata associated with the frame to decode are
+        required to be passed through the ``V4L2_CID_MPEG_VIDEO_H264_SPS``,
         ``V4L2_CID_MPEG_VIDEO_H264_PPS``,
         ``V4L2_CID_MPEG_VIDEO_H264_SCALING_MATRIX``,
         ``V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS`` and
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index cd1ae016706f..2c67f9fc4d5b 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -402,6 +402,11 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
                 "Explicit",
                 NULL,
         };
+        static const char * const h264_decode_mode[] = {
+                "Slice-Based",
+                "Frame-Based",
+                NULL,
+        };
         static const char * const mpeg_mpeg2_level[] = {
                 "Low",
                 "Main",
@@ -633,6 +638,8 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
                 return h264_fp_arrangement_type;
         case V4L2_CID_MPEG_VIDEO_H264_FMO_MAP_TYPE:
                 return h264_fmo_map_type;
+        case V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE:
+                return h264_decode_mode;
         case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:
                 return mpeg_mpeg2_level;
         case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:
@@ -852,6 +859,7 @@ const char *v4l2_ctrl_get_name(u32 id)
         case V4L2_CID_MPEG_VIDEO_H264_SCALING_MATRIX:           return "H264 Scaling Matrix";
         case V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS:             return "H264 Slice Parameters";
         case V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS:            return "H264 Decode Parameters";
+        case V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE:              return "H264 Decode Mode";
         case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:                   return "MPEG2 Level";
         case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:                 return "MPEG2 Profile";
         case V4L2_CID_MPEG_VIDEO_MPEG4_I_FRAME_QP:              return "MPEG4 I-Frame QP Value";
@@ -1220,6 +1228,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
         case V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_IDC:
         case V4L2_CID_MPEG_VIDEO_H264_SEI_FP_ARRANGEMENT_TYPE:
         case V4L2_CID_MPEG_VIDEO_H264_FMO_MAP_TYPE:
+        case V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE:
         case V4L2_CID_MPEG_VIDEO_MPEG2_LEVEL:
         case V4L2_CID_MPEG_VIDEO_MPEG2_PROFILE:
         case V4L2_CID_MPEG_VIDEO_MPEG4_LEVEL:
diff --git a/include/media/h264-ctrls.h b/include/media/h264-ctrls.h
index 6160a69c0143..928c48c57282 100644
--- a/include/media/h264-ctrls.h
+++ b/include/media/h264-ctrls.h
@@ -26,6 +26,7 @@
 #define V4L2_CID_MPEG_VIDEO_H264_SCALING_MATRIX (V4L2_CID_MPEG_BASE+1002)
 #define V4L2_CID_MPEG_VIDEO_H264_SLICE_PARAMS   (V4L2_CID_MPEG_BASE+1003)
 #define V4L2_CID_MPEG_VIDEO_H264_DECODE_PARAMS  (V4L2_CID_MPEG_BASE+1004)
+#define V4L2_CID_MPEG_VIDEO_H264_DECODE_MODE    (V4L2_CID_MPEG_BASE+1005)
 
 /* enum v4l2_ctrl_type type values */
 #define V4L2_CTRL_TYPE_H264_SPS                 0x0110
@@ -34,6 +35,11 @@
 #define V4L2_CTRL_TYPE_H264_SLICE_PARAMS        0x0113
 #define V4L2_CTRL_TYPE_H264_DECODE_PARAMS       0x0114
 
+enum v4l2_mpeg_video_h264_decode_mode {
+        V4L2_MPEG_VIDEO_H264_DECODE_MODE_SLICE_BASED,
+        V4L2_MPEG_VIDEO_H264_DECODE_MODE_FRAME_BASED,
+};
+
 #define V4L2_H264_SPS_CONSTRAINT_SET0_FLAG                      0x01
 #define V4L2_H264_SPS_CONSTRAINT_SET1_FLAG                      0x02
 #define V4L2_H264_SPS_CONSTRAINT_SET2_FLAG                      0x04
@@ -125,6 +131,10 @@ struct v4l2_h264_pred_weight_table {
 struct v4l2_ctrl_h264_slice_params {
         /* Size in bytes, including header */
         __u32 size;
+
+        /* Offset in bytes to the start of slice in the OUTPUT buffer. */
+        __u32 start_byte_offset;
+
         /* Offset in bits to slice_data() from the beginning of this slice. */
         __u32 header_bit_size;