Hi Sakari,
Thank you for the patch.
Mentioning V4L2 on the subject line would help differentiating this from
the media bus codes.
On Wed, Mar 13, 2024 at 09:24:43AM +0200, Sakari Ailus wrote:
> Generic 8-bit metadata formats define the in-memory data layout but not
> the format of the data itself. The reasoning for having such formats is to
> allow CSI-2 receiver drivers to receive and DMA drivers to write the data
> to memory without knowing a large number of device specific formats.
s/device specific/device-specific/
> These formats may be used only in conjunction of a Media controller
s/of a/with a/
> pipeline where the internal pad of the source sub-device defines the
> specific format of the data (using an mbus code).
>
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> ---
> .../userspace-api/media/v4l/dev-subdev.rst | 2 +
> .../userspace-api/media/v4l/meta-formats.rst | 1 +
> .../media/v4l/metafmt-generic.rst | 304 ++++++++++++++++++
> drivers/media/v4l2-core/v4l2-ioctl.c | 7 +
> include/uapi/linux/videodev2.h | 8 +
> 5 files changed, 322 insertions(+)
> create mode 100644 Documentation/userspace-api/media/v4l/metafmt-generic.rst
>
> diff --git a/Documentation/userspace-api/media/v4l/dev-subdev.rst b/Documentation/userspace-api/media/v4l/dev-subdev.rst
> index 43988516acdd..f375b820ab68 100644
> --- a/Documentation/userspace-api/media/v4l/dev-subdev.rst
> +++ b/Documentation/userspace-api/media/v4l/dev-subdev.rst
> @@ -506,6 +506,8 @@ source pads.
>
> subdev-formats
>
> +.. _subdev-routing:
> +
> Streams, multiplexed media pads and internal routing
> ----------------------------------------------------
>
> diff --git a/Documentation/userspace-api/media/v4l/meta-formats.rst b/Documentation/userspace-api/media/v4l/meta-formats.rst
> index 0bb61fc5bc00..919f595576b9 100644
> --- a/Documentation/userspace-api/media/v4l/meta-formats.rst
> +++ b/Documentation/userspace-api/media/v4l/meta-formats.rst
> @@ -19,3 +19,4 @@ These formats are used for the :ref:`metadata` interface only.
> metafmt-vsp1-hgo
> metafmt-vsp1-hgt
> metafmt-vivid
> + metafmt-generic
I think the intention was to keep those alphabetically sorted, even if
vivid is out of order already.
> diff --git a/Documentation/userspace-api/media/v4l/metafmt-generic.rst b/Documentation/userspace-api/media/v4l/metafmt-generic.rst
> new file mode 100644
> index 000000000000..2ebab1f895e0
> --- /dev/null
> +++ b/Documentation/userspace-api/media/v4l/metafmt-generic.rst
> @@ -0,0 +1,304 @@
> +.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later
> +
> +**************************************************************************************************************************************************************************************************************************************************************************************************************************
> +V4L2_META_FMT_GENERIC_8 ('MET8'), V4L2_META_FMT_GENERIC_CSI2_10 ('MC1A'), V4L2_META_FMT_GENERIC_CSI2_12 ('MC1C'), V4L2_META_FMT_GENERIC_CSI2_14 ('MC1E'), V4L2_META_FMT_GENERIC_CSI2_16 ('MC1G'), V4L2_META_FMT_GENERIC_CSI2_20 ('MC1K'), V4L2_META_FMT_GENERIC_CSI2_24 ('MC1O')
> +**************************************************************************************************************************************************************************************************************************************************************************************************************************
Aren't you supposed to match the line lengths ?
> +
> +
> +Generic line-based metadata formats
> +
> +
> +Description
> +===========
> +
> +These generic line-based metadata formats define the memory layout of the data
> +without defining the format or meaning of the metadata itself. These formats may
> +only be used with a Media controller pipeline where the more specific format is
"Media Controller" or "media controller", but not a hybrid mix.
> +defined in an :ref:`internal source pad <MEDIA-PAD-FL-INTERNAL>` of the source
s/defined in/reported by/
> +sub-device. See also :ref:`source routes <subdev-routing>`.
> +
> +.. _v4l2-meta-fmt-generic-8:
> +
> +V4L2_META_FMT_GENERIC_8
> +-----------------------
> +
> +The V4L2_META_FMT_GENERIC_8 format is a plain 8-bit metadata format.
> +
> +This format is also used on CSI-2 for both 8 bits per ``Data unit
s/Data unit/Data Unit/ (through the whole patch series)
> +<media-glossary-data-unit>`` as well as for 16 bits per Data unit when two bytes
> +of metadata are packed into one 16-bit Data unit.
> +
> +**Byte Order Of V4L2_META_FMT_GENERIC_8.**
> +Each cell is one byte. "M" denotes a byte of metadata.
> +
> +.. tabularcolumns:: |p{2.4cm}|p{1.2cm}|p{1.2cm}|p{1.2cm}|p{1.2cm}|
> +
> +.. flat-table::
Let's add a title here
.. flat-table:: Sample 4x2 Metadata Frame
(feel free to adjust). Same below.
> + :header-rows: 0
> + :stub-columns: 0
> + :widths: 12 8 8 8 8
> +
> + * - start + 0:
> + - M\ :sub:`00`
> + - M\ :sub:`10`
> + - M\ :sub:`20`
> + - M\ :sub:`30`
> + * - start + 4:
> + - M\ :sub:`01`
> + - M\ :sub:`11`
> + - M\ :sub:`21`
> + - M\ :sub:`31`
> +
> +.. _v4l2-meta-fmt-generic-csi2-10:
> +
> +V4L2_META_FMT_GENERIC_CSI2_10
> +-----------------------------
> +
> +V4L2_META_FMT_GENERIC_CSI2_10 contains packed 8-bit generic metadata, 10 bits
> +for each 8 bits of data. Every four bytes of metadata is followed by a single
> +byte of padding. The way the data is packed follows the MIPI CSI-2 specification
> +and the padding is defined in the MIPI CCS specification.
Doesn't really sound packed, when you have one byte of padding after
four bytes of data :-) I understand where this "packing" is from, but
the documentation seems confusing for people not familiar with the
topic. How about simplifying it as follows ?
V4L2_META_FMT_GENERIC_CSI2_10 contains 8-bit generic metadata, stored with one
padding byte after every four bytes of metadata. This is usually produced by
CSI-2 receivers with a source that transmits MEDIA_BUS_FMT_META_10, when the
CSI-2 receiver packs the received data as defined in the MIPI CSI-2
specification.
> +
> +This format is also used in conjunction with 20 bits per ``Data unit
> +<media-glossary-data-unit>`` formats that pack two bytes of metadata into one
> +Data unit.
> +
> +This format is little endian.
How is it little endian when it's byte-oriented ?
> +
> +**Byte Order Of V4L2_META_FMT_GENERIC_CSI2_10.**
> +Each cell is one byte. "M" denotes a byte of metadata and "X" a byte of padding.
'M' and 'x'.
These comments apply to the formats below too.
> +
> +.. tabularcolumns:: |p{2.4cm}|p{1.2cm}|p{1.2cm}|p{1.2cm}|p{1.2cm}|p{.8cm}|
> +
> +.. flat-table::
> + :header-rows: 0
> + :stub-columns: 0
> + :widths: 12 8 8 8 8 8
> +
> + * - start + 0:
> + - M\ :sub:`00`
> + - M\ :sub:`10`
> + - M\ :sub:`20`
> + - M\ :sub:`30`
> + - X
> + * - start + 5:
> + - M\ :sub:`01`
> + - M\ :sub:`11`
> + - M\ :sub:`21`
> + - M\ :sub:`31`
> + - X
> +
> +.. _v4l2-meta-fmt-generic-csi2-12:
> +
> +V4L2_META_FMT_GENERIC_CSI2_12
> +-----------------------------
> +
> +V4L2_META_FMT_GENERIC_CSI2_12 contains packed 8-bit generic metadata, 12 bits
> +for each 8 bits of data. Every four bytes of metadata is followed by a single
> +byte of padding. The way the data is packed follows the MIPI CSI-2 specification
> +and the padding is defined in the MIPI CCS specification.
> +
> +This format is also used in conjunction with 24 bits per ``Data unit
> +<media-glossary-data-unit>`` formats that pack two bytes of metadata into one
> +Data unit.
> +
> +This format is little endian.
> +
> +**Byte Order Of V4L2_META_FMT_GENERIC_CSI2_12.**
> +Each cell is one byte. "M" denotes a byte of metadata and "X" a byte of padding.
> +
> +.. tabularcolumns:: |p{2.4cm}|p{1.2cm}|p{1.2cm}|p{1.2cm}|p{1.2cm}|p{.8cm}|p{.8cm}|
> +
> +.. flat-table::
> + :header-rows: 0
> + :stub-columns: 0
> + :widths: 12 8 8 8 8 8 8
> +
> + * - start + 0:
> + - M\ :sub:`00`
> + - M\ :sub:`10`
> + - X
> + - M\ :sub:`20`
> + - M\ :sub:`30`
> + - X
> + * - start + 6:
> + - M\ :sub:`01`
> + - M\ :sub:`11`
> + - X
> + - M\ :sub:`21`
> + - M\ :sub:`31`
> + - X
> +
> +.. _v4l2-meta-fmt-generic-csi2-14:
> +
> +V4L2_META_FMT_GENERIC_CSI2_14
> +-----------------------------
> +
> +V4L2_META_FMT_GENERIC_CSI2_14 contains packed 8-bit generic metadata, 14 bits
> +for each 8 bits of data. Every four bytes of metadata is followed by three bytes
> +of padding. The way the data is packed follows the MIPI CSI-2 specification and
> +the padding is defined in the MIPI CCS specification.
> +
> +This format is little endian.
> +
> +**Byte Order Of V4L2_META_FMT_GENERIC_CSI2_14.**
> +Each cell is one byte. "M" denotes a byte of metadata and "X" a byte of padding.
> +
> +.. tabularcolumns:: |p{2.4cm}|p{1.2cm}|p{1.2cm}|p{1.2cm}|p{1.2cm}|p{.8cm}|p{.8cm}|p{.8cm}|
> +
> +.. flat-table::
> + :header-rows: 0
> + :stub-columns: 0
> + :widths: 12 8 8 8 8 8 8 8
> +
> + * - start + 0:
> + - M\ :sub:`00`
> + - M\ :sub:`10`
> + - M\ :sub:`20`
> + - M\ :sub:`30`
> + - X
> + - X
> + - X
> + * - start + 7:
> + - M\ :sub:`01`
> + - M\ :sub:`11`
> + - M\ :sub:`21`
> + - M\ :sub:`31`
> + - X
> + - X
> + - X
> +
> +.. _v4l2-meta-fmt-generic-csi2-16:
> +
> +V4L2_META_FMT_GENERIC_CSI2_16
> +-----------------------------
> +
> +V4L2_META_FMT_GENERIC_CSI2_16 contains packed 8-bit generic metadata, 16 bits
> +for each 8 bits of data. Every byte of metadata is followed by one byte of
> +padding. The way the data is packed follows the MIPI CSI-2 specification and the
> +padding is defined in the MIPI CCS specification.
> +
> +This format is little endian.
> +
> +**Byte Order Of V4L2_META_FMT_GENERIC_CSI2_16.**
> +Each cell is one byte. "M" denotes a byte of metadata and "X" a byte of padding.
> +
> +.. tabularcolumns:: |p{2.4cm}|p{1.2cm}|p{.8cm}|p{1.2cm}|p{.8cm}|p{1.2cm}|p{.8cm}|p{1.2cm}|p{.8cm}|
> +
> +.. flat-table::
> + :header-rows: 0
> + :stub-columns: 0
> + :widths: 12 8 8 8 8 8 8 8 8
> +
> + * - start + 0:
> + - M\ :sub:`00`
> + - X
> + - M\ :sub:`10`
> + - X
> + - M\ :sub:`20`
> + - X
> + - M\ :sub:`30`
> + - X
> + * - start + 8:
> + - M\ :sub:`01`
> + - X
> + - M\ :sub:`11`
> + - X
> + - M\ :sub:`21`
> + - X
> + - M\ :sub:`31`
> + - X
> +
> +.. _v4l2-meta-fmt-generic-csi2-20:
> +
> +V4L2_META_FMT_GENERIC_CSI2_20
> +-----------------------------
> +
> +V4L2_META_FMT_GENERIC_CSI2_20 contains packed 8-bit generic metadata, 20 bits
> +for each 8 bits of data. Every byte of metadata is followed by alternating one
> +and two bytes of padding. The way the data is packed follows the MIPI CSI-2
> +specification and the padding is defined in the MIPI CCS specification.
> +
> +This format is little endian.
> +
> +**Byte Order Of V4L2_META_FMT_GENERIC_CSI2_20.**
> +Each cell is one byte. "M" denotes a byte of metadata and "X" a byte of padding.
> +
> +.. tabularcolumns:: |p{2.4cm}|p{1.2cm}|p{.8cm}|p{1.2cm}|p{.8cm}|p{.8cm}|p{1.2cm}|p{.8cm}|p{1.2cm}|p{.8cm}|p{.8cm}|
> +
> +.. flat-table::
> + :header-rows: 0
> + :stub-columns: 0
> + :widths: 12 8 8 8 8 8 8 8 8 8 8
> +
> + * - start + 0:
> + - M\ :sub:`00`
> + - X
> + - M\ :sub:`10`
> + - X
> + - X
> + - M\ :sub:`20`
> + - X
> + - M\ :sub:`30`
> + - X
> + - X
> + * - start + 10:
> + - M\ :sub:`01`
> + - X
> + - M\ :sub:`11`
> + - X
> + - X
> + - M\ :sub:`21`
> + - X
> + - M\ :sub:`31`
> + - X
> + - X
> +
> +.. _v4l2-meta-fmt-generic-csi2-24:
> +
> +V4L2_META_FMT_GENERIC_CSI2_24
> +-----------------------------
> +
> +V4L2_META_FMT_GENERIC_CSI2_24 contains packed 8-bit generic metadata, 24 bits
> +for each 8 bits of data. Every byte of metadata is followed by two bytes of
> +padding. The way the data is packed follows the MIPI CSI-2 specification and the
> +padding is defined in the MIPI CCS specification.
> +
> +This format is little endian.
> +
> +**Byte Order Of V4L2_META_FMT_GENERIC_CSI2_24.**
> +Each cell is one byte. "M" denotes a byte of metadata and "X" a byte of padding.
> +
> +.. tabularcolumns:: |p{2.4cm}|p{1.2cm}|p{.8cm}|p{.8cm}|p{1.2cm}|p{.8cm}|p{.8cm}|p{1.2cm}|p{.8cm}|p{.8cm}|p{1.2cm}|p{.8cm}|p{.8cm}|
> +
> +.. flat-table::
> + :header-rows: 0
> + :stub-columns: 0
> + :widths: 12 8 8 8 8 8 8 8 8 8 8 8 8
> +
> + * - start + 0:
> + - M\ :sub:`00`
> + - X
> + - X
> + - M\ :sub:`10`
> + - X
> + - X
> + - M\ :sub:`20`
> + - X
> + - X
> + - M\ :sub:`30`
> + - X
> + - X
> + * - start + 12:
> + - M\ :sub:`01`
> + - X
> + - X
> + - M\ :sub:`11`
> + - X
> + - X
> + - M\ :sub:`21`
> + - X
> + - X
> + - M\ :sub:`31`
> + - X
> + - X
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 33076af4dfdb..7cb6063f7056 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1452,6 +1452,13 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
> case V4L2_PIX_FMT_Y210: descr = "10-bit YUYV Packed"; break;
> case V4L2_PIX_FMT_Y212: descr = "12-bit YUYV Packed"; break;
> case V4L2_PIX_FMT_Y216: descr = "16-bit YUYV Packed"; break;
> + case V4L2_META_FMT_GENERIC_8: descr = "8-bit Generic Metadata"; break;
> + case V4L2_META_FMT_GENERIC_CSI2_10: descr = "8b Generic Meta, 10b CSI-2"; break;
You could write "8-bit Generic Meta, 10b CSI-2" and it would still fit.
Up to you.
> + case V4L2_META_FMT_GENERIC_CSI2_12: descr = "8b Generic Meta, 12b CSI-2"; break;
> + case V4L2_META_FMT_GENERIC_CSI2_14: descr = "8b Generic Meta, 14b CSI-2"; break;
> + case V4L2_META_FMT_GENERIC_CSI2_16: descr = "8b Generic Meta, 16b CSI-2"; break;
> + case V4L2_META_FMT_GENERIC_CSI2_20: descr = "8b Generic Meta, 20b CSI-2"; break;
> + case V4L2_META_FMT_GENERIC_CSI2_24: descr = "8b Generic Meta, 24b CSI-2"; break;
>
> default:
> /* Compressed formats */
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index a8015e5e7fa4..6a4f8ae30186 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -839,6 +839,14 @@ struct v4l2_pix_format {
> #define V4L2_META_FMT_RK_ISP1_PARAMS v4l2_fourcc('R', 'K', '1', 'P') /* Rockchip ISP1 3A Parameters */
> #define V4L2_META_FMT_RK_ISP1_STAT_3A v4l2_fourcc('R', 'K', '1', 'S') /* Rockchip ISP1 3A Statistics */
>
> +#define V4L2_META_FMT_GENERIC_8 v4l2_fourcc('M', 'E', 'T', '8') /* Generic 8-bit metadata */
> +#define V4L2_META_FMT_GENERIC_CSI2_10 v4l2_fourcc('M', 'C', '1', 'A') /* 10-bit CSI-2 packed 8-bit metadata */
> +#define V4L2_META_FMT_GENERIC_CSI2_12 v4l2_fourcc('M', 'C', '1', 'C') /* 12-bit CSI-2 packed 8-bit metadata */
> +#define V4L2_META_FMT_GENERIC_CSI2_14 v4l2_fourcc('M', 'C', '1', 'E') /* 14-bit CSI-2 packed 8-bit metadata */
> +#define V4L2_META_FMT_GENERIC_CSI2_16 v4l2_fourcc('M', 'C', '1', 'G') /* 16-bit CSI-2 packed 8-bit metadata */
> +#define V4L2_META_FMT_GENERIC_CSI2_20 v4l2_fourcc('M', 'C', '1', 'K') /* 20-bit CSI-2 packed 8-bit metadata */
> +#define V4L2_META_FMT_GENERIC_CSI2_24 v4l2_fourcc('M', 'C', '1', 'O') /* 24-bit CSI-2 packed 8-bit metadata */
> +
> /* priv field value to indicates that subsequent fields are valid. */
> #define V4L2_PIX_FMT_PRIV_MAGIC 0xfeedcafe
>
--
Regards,
Laurent Pinchart
