[PATCH v12 09/17] media: uapi: HEVC: Define V4L2_CID_STATELESS_HEVC_SLICE_PARAMS as a dynamic array

[Benjamin Gaignard]

Make explicit that V4L2_CID_STATELESS_HEVC_SLICE_PARAMS control is
a dynamic array control type.
Some drivers may be able to receive multiple slices in one control
to improve decoding performance.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
---
 Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst | 2 ++
 drivers/media/v4l2-core/v4l2-ctrls-defs.c                 | 1 +
 drivers/staging/media/sunxi/cedrus/cedrus.c               | 2 ++
 include/media/hevc-ctrls.h                                | 3 +++
 4 files changed, 8 insertions(+)

diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
index e88b5e6944a6..c2e0adece613 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst
@@ -2986,6 +2986,8 @@ enum v4l2_mpeg_video_hevc_size_of_length_field -
     These bitstream parameters are defined according to :ref:`hevc`.
     They are described in section 7.4.7 "General slice segment header
     semantics" of the specification.
+    This control is a dynamically sized 1-dimensional array,
+    V4L2_CTRL_FLAG_DYNAMIC_ARRAY flag must be set when using it.
 
 .. c:type:: v4l2_ctrl_hevc_slice_params
 
diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
index 9f55503cd3d6..d594efbcbb93 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c
@@ -1510,6 +1510,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type,
 		break;
 	case V4L2_CID_STATELESS_HEVC_SLICE_PARAMS:
 		*type = V4L2_CTRL_TYPE_HEVC_SLICE_PARAMS;
+		*flags |= V4L2_CTRL_FLAG_DYNAMIC_ARRAY;
 		break;
 	case V4L2_CID_STATELESS_HEVC_SCALING_MATRIX:
 		*type = V4L2_CTRL_TYPE_HEVC_SCALING_MATRIX;
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.c b/drivers/staging/media/sunxi/cedrus/cedrus.c
index 87be975a72b6..b12219123a6b 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus.c
@@ -178,6 +178,8 @@ static const struct cedrus_control cedrus_controls[] = {
 	{
 		.cfg = {
 			.id	= V4L2_CID_STATELESS_HEVC_SLICE_PARAMS,
+			/* The driver can only handle 1 entry per slice for now */
+			.dims   = { 1 },
 		},
 		.codec		= CEDRUS_CODEC_H265,
 	},
diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h
index 57053cfa099b..341fc795d550 100644
--- a/include/media/hevc-ctrls.h
+++ b/include/media/hevc-ctrls.h
@@ -314,6 +314,9 @@ struct v4l2_hevc_pred_weight_table {
 /**
  * struct v4l2_ctrl_hevc_slice_params - HEVC slice parameters
  *
+ * This control is a dynamically sized 1-dimensional array,
+ * V4L2_CTRL_FLAG_DYNAMIC_ARRAY flag must be set when using it.
+ *
  * @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
  * @nal_unit_type: specifies the coding type of the slice (B, P or I)
-- 
2.32.0