Hi Sakari,
Thank you for the patch.
On Tue, Apr 16, 2024 at 10:32:40PM +0300, Sakari Ailus wrote:
> Many camera sensors, among other devices, transmit embedded data and image
> data for each CSI-2 frame. This embedded data typically contains register
> configuration of the sensor that has been used to capture the image data
> of the same frame.
>
> The embedded data is received by the CSI-2 receiver and has the same
> properties as the image data, including that it is line based: it has
> width, height and bytesperline (stride).
>
> Add these fields to struct v4l2_meta_format and document them.
>
> Also add V4L2_FMT_FLAG_META_LINE_BASED to tell a given format is
> line-based i.e. these fields of struct v4l2_meta_format are valid for it.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> ---
> .../userspace-api/media/v4l/dev-meta.rst | 21 +++++++++++++++++++
> .../media/v4l/vidioc-enum-fmt.rst | 7 +++++++
> .../media/videodev2.h.rst.exceptions | 1 +
> drivers/media/v4l2-core/v4l2-ioctl.c | 5 +++--
> include/uapi/linux/videodev2.h | 10 +++++++++
> 5 files changed, 42 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/userspace-api/media/v4l/dev-meta.rst b/Documentation/userspace-api/media/v4l/dev-meta.rst
> index 0e7e1ee1471a..5eee9ab60395 100644
> --- a/Documentation/userspace-api/media/v4l/dev-meta.rst
> +++ b/Documentation/userspace-api/media/v4l/dev-meta.rst
> @@ -47,6 +47,12 @@ member of the ``fmt`` union as needed per the desired operation. Both drivers
> and applications must set the remainder of the :c:type:`v4l2_format` structure
> to 0.
>
> +Devices that capture metadata by line have the struct v4l2_fmtdesc
> +``V4L2_FMT_FLAG_META_LINE_BASED`` flag set for :c:func:`VIDIOC_ENUM_FMT`. Such
> +devices can typically also :ref:`capture image data <capture>`. This primarily
> +involves devices that receive the data from a different devices such as a camera
> +sensor.
> +
> .. c:type:: v4l2_meta_format
>
> .. tabularcolumns:: |p{1.4cm}|p{2.4cm}|p{13.5cm}|
> @@ -65,3 +71,18 @@ to 0.
> - ``buffersize``
> - Maximum buffer size in bytes required for data. The value is set by the
> driver.
> + * - __u32
> + - ``width``
> + - Width of a line of metadata in Data Units. Valid when
> + :c:type`v4l2_fmtdesc` flag ``V4L2_FMT_FLAG_META_LINE_BASED`` is set,
> + otherwise zero. See :c:func:`VIDIOC_ENUM_FMT`.
> + * - __u32
> + - ``height``
> + - Number of rows of metadata. Valid when :c:type`v4l2_fmtdesc` flag
> + ``V4L2_FMT_FLAG_META_LINE_BASED`` is set, otherwise zero. See
> + :c:func:`VIDIOC_ENUM_FMT`.
> + * - __u32
> + - ``bytesperline``
> + - Offset in bytes between the beginning of two consecutive lines. Valid
> + when :c:type`v4l2_fmtdesc` flag ``V4L2_FMT_FLAG_META_LINE_BASED`` is
> + set, otherwise zero. See :c:func:`VIDIOC_ENUM_FMT`.
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> index 000c154b0f98..a439be1b15d1 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
> @@ -227,6 +227,13 @@ the ``mbus_code`` field is handled differently:
> The application can ask to configure the quantization of the capture
> device when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with
> :ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
> + * - ``V4L2_FMT_FLAG_META_LINE_BASED``
> + - 0x0200
> + - The metadata format is line-based. In this case the ``width``,
> + ``height`` and ``bytesperline`` fields of :c:type:`v4l2_meta_format` are
> + valid. The buffer consists of ``height`` lines, each having ``width``
> + Data Units of data and offset (in bytes) between the beginning of each
s/and offset/, and the offset/
> + two consecutive lines is ``bytesperline``.
>
> Return Value
> ============
> diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> index 3e58aac4ef0b..bdc628e8c1d6 100644
> --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
> @@ -215,6 +215,7 @@ replace define V4L2_FMT_FLAG_CSC_XFER_FUNC fmtdesc-flags
> replace define V4L2_FMT_FLAG_CSC_YCBCR_ENC fmtdesc-flags
> replace define V4L2_FMT_FLAG_CSC_HSV_ENC fmtdesc-flags
> replace define V4L2_FMT_FLAG_CSC_QUANTIZATION fmtdesc-flags
> +replace define V4L2_FMT_FLAG_META_LINE_BASED fmtdesc-flags
>
> # V4L2 timecode types
> replace define V4L2_TC_TYPE_24FPS timecode-type
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index ae2dca7f2817..2cfc9106857a 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -343,8 +343,9 @@ static void v4l_print_format(const void *arg, bool write_only)
> case V4L2_BUF_TYPE_META_OUTPUT:
> meta = &p->fmt.meta;
> pixelformat = meta->dataformat;
> - pr_cont(", dataformat=%p4cc, buffersize=%u\n",
> - &pixelformat, meta->buffersize);
> + pr_cont(", dataformat=%p4cc, buffersize=%u, width=%u, height=%u, bytesperline=%u\n",
> + &pixelformat, meta->buffersize, meta->width,
> + meta->height, meta->bytesperline);
> break;
> }
> }
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index c7cf20b5da67..37112dfebd0c 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -877,6 +877,7 @@ struct v4l2_fmtdesc {
> #define V4L2_FMT_FLAG_CSC_YCBCR_ENC 0x0080
> #define V4L2_FMT_FLAG_CSC_HSV_ENC V4L2_FMT_FLAG_CSC_YCBCR_ENC
> #define V4L2_FMT_FLAG_CSC_QUANTIZATION 0x0100
> +#define V4L2_FMT_FLAG_META_LINE_BASED 0x0200
Could the V4L2_FMT_FLAG_META_LINE_BASED flag be set by the V4L2 core for
line-based metadata formats, instead of requiring drivers to set it ? It
would ensure consistency.
>
> /* Frame Size and frame rate enumeration */
> /*
> @@ -2424,10 +2425,19 @@ struct v4l2_sdr_format {
> * struct v4l2_meta_format - metadata format definition
> * @dataformat: little endian four character code (fourcc)
> * @buffersize: maximum size in bytes required for data
> + * @width: number of data units of data per line (valid for line
> + * based formats only, see format documentation)
> + * @height: number of lines of data per buffer (valid for line based
> + * formats only)
> + * @bytesperline: offset between the beginnings of two adjacent lines in
> + * bytes (valid for line based formats only)
> */
> struct v4l2_meta_format {
> __u32 dataformat;
> __u32 buffersize;
> + __u32 width;
> + __u32 height;
> + __u32 bytesperline;
> } __attribute__ ((packed));
>
> /**
--
Regards,
Laurent Pinchart
