diff mbox series

[v8,09/13] media: uapi: Add a control for HANTRO driver

Message ID 20210401160003.88803-10-benjamin.gaignard@collabora.com (mailing list archive)
State New
Headers show
Series Add HANTRO G2/HEVC decoder support for IMX8MQ | expand

Commit Message

Benjamin Gaignard April 1, 2021, 3:59 p.m. UTC
The HEVC HANTRO driver needs to know the number of bits to skip at
the beginning of the slice header.
That is a hardware specific requirement so create a dedicated control
that this purpose.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
---
version 5:
 - Be even more verbose in control documentation.
 - Do not create class for the control.
version 4:
- The control is now an integer which is enough to provide the numbers
  of bits to skip.
version 3:
- Fix typo in field name

 .../userspace-api/media/drivers/hantro.rst         | 14 ++++++++++++++
 .../userspace-api/media/drivers/index.rst          |  1 +
 include/uapi/linux/v4l2-controls.h                 | 13 +++++++++++++
 3 files changed, 28 insertions(+)
 create mode 100644 Documentation/userspace-api/media/drivers/hantro.rst

Comments

Ezequiel Garcia April 2, 2021, 12:27 p.m. UTC | #1
Hi Benjamin,

Thanks for the patch.

On Thu, 2021-04-01 at 17:59 +0200, Benjamin Gaignard wrote:
> The HEVC HANTRO driver needs to know the number of bits to skip at
> the beginning of the slice header.
> That is a hardware specific requirement so create a dedicated control
> that this purpose.
> 
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
> ---
> version 5:
>  - Be even more verbose in control documentation.
>  - Do not create class for the control.
> version 4:
> - The control is now an integer which is enough to provide the numbers
>   of bits to skip.
> version 3:
> - Fix typo in field name
> 
>  .../userspace-api/media/drivers/hantro.rst         | 14 ++++++++++++++
>  .../userspace-api/media/drivers/index.rst          |  1 +
>  include/uapi/linux/v4l2-controls.h                 | 13 +++++++++++++
>  3 files changed, 28 insertions(+)
>  create mode 100644 Documentation/userspace-api/media/drivers/hantro.rst
> 
> diff --git a/Documentation/userspace-api/media/drivers/hantro.rst b/Documentation/userspace-api/media/drivers/hantro.rst
> new file mode 100644
> index 000000000000..78dcd2a44a03
> --- /dev/null
> +++ b/Documentation/userspace-api/media/drivers/hantro.rst
> @@ -0,0 +1,14 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +Hantro video decoder driver
> +===========================
> +
> +The Hantro video decoder driver implements the following driver-specific controls:
> +
> +``V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP (integer)``
> +    Specifies to Hantro HEVC video decoder driver the number of data (in bits) to
> +    skip in the slice segment header.
> +    If non-IDR, the bits to be skipped go from syntax element "pic_output_flag"
> +    to before syntax element "slice_temporal_mvp_enabled_flag".
> +    If IDR, the skipped bits are just "pic_output_flag"
> +    (separate_colour_plane_flag is not supported).
> diff --git a/Documentation/userspace-api/media/drivers/index.rst b/Documentation/userspace-api/media/drivers/index.rst
> index 1a9038f5f9fa..12e3c512d718 100644
> --- a/Documentation/userspace-api/media/drivers/index.rst
> +++ b/Documentation/userspace-api/media/drivers/index.rst
> @@ -33,6 +33,7 @@ For more details see the file COPYING in the source distribution of Linux.
>  
>         ccs
>         cx2341x-uapi
> +        hantro
>         imx-uapi
>         max2175
>         meye-uapi
> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> index f3376aafea65..1dfb874b6272 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -869,6 +869,19 @@ enum v4l2_mpeg_mfc51_video_force_frame_type {
>  #define V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_STATIC              (V4L2_CID_CODEC_MFC51_BASE+53)
>  #define V4L2_CID_MPEG_MFC51_VIDEO_H264_NUM_REF_PIC_FOR_P               (V4L2_CID_CODEC_MFC51_BASE+54)
>  
> +/*  MPEG-class control IDs specific to the Hantro driver as defined by V4L2 */

We are moving away from "MPEG" terminology for codecs.

> +#define V4L2_CID_CODEC_HANTRO_BASE                             (V4L2_CTRL_CLASS_CODEC | 0x1200)

Using V4L2_CTRL_CLASS_CODEC_STATELESS is IMO better,
since this belongs to a stateless decoder.

And also, since we are still a bit unsure about the
syntax of this parameter (given it's not documented):

how about keeping the V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP
definition in drivers/staging/media/hantro/hantro.h ?

This would be a hint for applications that this control
is a quirk.

Hans, Philipp, any thoughts on this?

Regards,
Ezequiel
diff mbox series

Patch

diff --git a/Documentation/userspace-api/media/drivers/hantro.rst b/Documentation/userspace-api/media/drivers/hantro.rst
new file mode 100644
index 000000000000..78dcd2a44a03
--- /dev/null
+++ b/Documentation/userspace-api/media/drivers/hantro.rst
@@ -0,0 +1,14 @@ 
+.. SPDX-License-Identifier: GPL-2.0
+
+Hantro video decoder driver
+===========================
+
+The Hantro video decoder driver implements the following driver-specific controls:
+
+``V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP (integer)``
+    Specifies to Hantro HEVC video decoder driver the number of data (in bits) to
+    skip in the slice segment header.
+    If non-IDR, the bits to be skipped go from syntax element "pic_output_flag"
+    to before syntax element "slice_temporal_mvp_enabled_flag".
+    If IDR, the skipped bits are just "pic_output_flag"
+    (separate_colour_plane_flag is not supported).
diff --git a/Documentation/userspace-api/media/drivers/index.rst b/Documentation/userspace-api/media/drivers/index.rst
index 1a9038f5f9fa..12e3c512d718 100644
--- a/Documentation/userspace-api/media/drivers/index.rst
+++ b/Documentation/userspace-api/media/drivers/index.rst
@@ -33,6 +33,7 @@  For more details see the file COPYING in the source distribution of Linux.
 
 	ccs
 	cx2341x-uapi
+        hantro
 	imx-uapi
 	max2175
 	meye-uapi
diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
index f3376aafea65..1dfb874b6272 100644
--- a/include/uapi/linux/v4l2-controls.h
+++ b/include/uapi/linux/v4l2-controls.h
@@ -869,6 +869,19 @@  enum v4l2_mpeg_mfc51_video_force_frame_type {
 #define V4L2_CID_MPEG_MFC51_VIDEO_H264_ADAPTIVE_RC_STATIC		(V4L2_CID_CODEC_MFC51_BASE+53)
 #define V4L2_CID_MPEG_MFC51_VIDEO_H264_NUM_REF_PIC_FOR_P		(V4L2_CID_CODEC_MFC51_BASE+54)
 
+/*  MPEG-class control IDs specific to the Hantro driver as defined by V4L2 */
+#define V4L2_CID_CODEC_HANTRO_BASE				(V4L2_CTRL_CLASS_CODEC | 0x1200)
+/*
+ * V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP -
+ * the number of data (in bits) to skip in the
+ * slice segment header.
+ * If non-IDR, the bits to be skipped go from syntax element "pic_output_flag"
+ * to before syntax element "slice_temporal_mvp_enabled_flag".
+ * If IDR, the skipped bits are just "pic_output_flag"
+ * (separate_colour_plane_flag is not supported).
+ */
+#define V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP	(V4L2_CID_CODEC_HANTRO_BASE + 0)
+
 /*  Camera class control IDs */
 
 #define V4L2_CID_CAMERA_CLASS_BASE	(V4L2_CTRL_CLASS_CAMERA | 0x900)