From ebd995296afa99a5c53f164e595f7a6d41d32a01 Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Thu, 23 Aug 2018 09:56:22 -0400 Subject: [PATCH] media: videodev2.h: add new capabilities for buffer types Upstream commit f35f5d72e70e6b91389eb98fcabf43b79f40587f VIDIOC_REQBUFS and VIDIOC_CREATE_BUFFERS will return capabilities telling userspace what the given buffer type is capable of. Signed-off-by: Hans Verkuil Reviewed-by: Tomasz Figa Acked-by: Sakari Ailus Signed-off-by: Mauro Carvalho Chehab --- .../media/uapi/v4l/vidioc-create-bufs.rst | 14 ++++++- .../media/uapi/v4l/vidioc-reqbufs.rst | 42 ++++++++++++++++++- include/uapi/linux/videodev2.h | 13 +++++- 3 files changed, 65 insertions(+), 4 deletions(-) --- a/Documentation/media/uapi/v4l/vidioc-create-bufs.rst +++ b/Documentation/media/uapi/v4l/vidioc-create-bufs.rst @@ -102,7 +102,19 @@ than the number requested. - ``format`` - Filled in by the application, preserved by the driver. * - __u32 - - ``reserved``\ [8] + - ``capabilities`` + - Set by the driver. If 0, then the driver doesn't support + capabilities. In that case all you know is that the driver is + guaranteed to support ``V4L2_MEMORY_MMAP`` and *might* support + other :c:type:`v4l2_memory` types. It will not support any others + capabilities. See :ref:`here ` for a list of the + capabilities. + + If you want to just query the capabilities without making any + other changes, then set ``count`` to 0, ``memory`` to + ``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type. + * - __u32 + - ``reserved``\ [7] - A place holder for future extensions. Drivers and applications must set the array to zero. --- a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst +++ b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst @@ -88,10 +88,50 @@ any DMA in progress, an implicit ``V4L2_MEMORY_DMABUF`` or ``V4L2_MEMORY_USERPTR``. See :c:type:`v4l2_memory`. * - __u32 - - ``reserved``\ [2] + - ``capabilities`` + - Set by the driver. If 0, then the driver doesn't support + capabilities. In that case all you know is that the driver is + guaranteed to support ``V4L2_MEMORY_MMAP`` and *might* support + other :c:type:`v4l2_memory` types. It will not support any others + capabilities. + + If you want to query the capabilities with a minimum of side-effects, + then this can be called with ``count`` set to 0, ``memory`` set to + ``V4L2_MEMORY_MMAP`` and ``type`` set to the buffer type. This will + free any previously allocated buffers, so this is typically something + that will be done at the start of the application. + * - __u32 + - ``reserved``\ [1] - A place holder for future extensions. Drivers and applications must set the array to zero. +.. tabularcolumns:: |p{6.1cm}|p{2.2cm}|p{8.7cm}| + +.. _v4l2-buf-capabilities: +.. _V4L2-BUF-CAP-SUPPORTS-MMAP: +.. _V4L2-BUF-CAP-SUPPORTS-USERPTR: +.. _V4L2-BUF-CAP-SUPPORTS-DMABUF: +.. _V4L2-BUF-CAP-SUPPORTS-REQUESTS: + +.. cssclass:: longtable + +.. flat-table:: V4L2 Buffer Capabilities Flags + :header-rows: 0 + :stub-columns: 0 + :widths: 3 1 4 + + * - ``V4L2_BUF_CAP_SUPPORTS_MMAP`` + - 0x00000001 + - This buffer type supports the ``V4L2_MEMORY_MMAP`` streaming mode. + * - ``V4L2_BUF_CAP_SUPPORTS_USERPTR`` + - 0x00000002 + - This buffer type supports the ``V4L2_MEMORY_USERPTR`` streaming mode. + * - ``V4L2_BUF_CAP_SUPPORTS_DMABUF`` + - 0x00000004 + - This buffer type supports the ``V4L2_MEMORY_DMABUF`` streaming mode. + * - ``V4L2_BUF_CAP_SUPPORTS_REQUESTS`` + - 0x00000008 + - This buffer type supports :ref:`requests `. Return Value ============ --- a/include/uapi/linux/videodev2.h +++ b/include/uapi/linux/videodev2.h @@ -872,9 +872,16 @@ struct v4l2_requestbuffers { __u32 count; __u32 type; /* enum v4l2_buf_type */ __u32 memory; /* enum v4l2_memory */ - __u32 reserved[2]; + __u32 capabilities; + __u32 reserved[1]; }; +/* capabilities for struct v4l2_requestbuffers and v4l2_create_buffers */ +#define V4L2_BUF_CAP_SUPPORTS_MMAP (1 << 0) +#define V4L2_BUF_CAP_SUPPORTS_USERPTR (1 << 1) +#define V4L2_BUF_CAP_SUPPORTS_DMABUF (1 << 2) +#define V4L2_BUF_CAP_SUPPORTS_REQUESTS (1 << 3) + /** * struct v4l2_plane - plane info for multi-planar buffers * @bytesused: number of bytes occupied by data in the plane (payload) @@ -2318,6 +2325,7 @@ struct v4l2_dbg_chip_info { * return: number of created buffers * @memory: enum v4l2_memory; buffer memory type * @format: frame format, for which buffers are requested + * @capabilities: capabilities of this buffer type. * @reserved: future extensions */ struct v4l2_create_buffers { @@ -2325,7 +2333,8 @@ struct v4l2_create_buffers { __u32 count; __u32 memory; struct v4l2_format format; - __u32 reserved[8]; + __u32 capabilities; + __u32 reserved[7]; }; /*