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media: videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag

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This patch lets user-space request a non-coherent memory
allocation during CREATE_BUFS and REQBUFS ioctl calls.

= CREATE_BUFS

  struct v4l2_create_buffers has seven 4-byte reserved areas,
  so reserved[0] is renamed to ->flags. The struct, thus, now
  has six reserved 4-byte regions.

= CREATE_BUFS32

  struct v4l2_create_buffers32 has seven 4-byte reserved areas,
  so reserved[0] is renamed to ->flags. The struct, thus, now
  has six reserved 4-byte regions.

= REQBUFS

 We use one byte of a 4 byte ->reserved[1] member of struct
 v4l2_requestbuffers. The struct, thus, now has reserved 3 bytes.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This commit is contained in:
Sergey Senozhatsky
2021-09-09 13:24:29 +02:00
committed by Mauro Carvalho Chehab
parent b00a9e59c5
commit c0acf9cfee
7 changed files with 60 additions and 15 deletions
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7
Documentation/userspace-api/media/v4l/vidioc-create-bufs.rst
View File

@@ -113,7 +113,12 @@ than the number requested.
``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type.
* - __u32
- ``reserved``\ [7]
- ``flags``
- Specifies additional buffer management attributes.
See :ref:`memory-flags`.
* - __u32
- ``reserved``\ [6]
- A place holder for future extensions. Drivers and applications
must set the array to zero.

11
Documentation/userspace-api/media/v4l/vidioc-reqbufs.rst
View File

@@ -104,10 +104,13 @@ aborting or finishing any DMA in progress, an implicit
``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.
* - __u8
- ``flags``
- Specifies additional buffer management attributes.
See :ref:`memory-flags`.
* - __u8
- ``reserved``\ [3]
- Reserved for future extensions.
.. _v4l2-buf-capabilities:
.. _V4L2-BUF-CAP-SUPPORTS-MMAP: