54f38fcae5
Since 2017, there is an space reserved for userspace API,
created by changeset 1d596dee3862 ("docs: Create a user-space API guide").
As the media subsystem was one of the first subsystems to use
Sphinx, until this patch, we were keeping things on a separate
place.
Let's just use the new location, as having all uAPI altogether
will likely make things easier for developers.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
66 lines
1.5 KiB
ReStructuredText
66 lines
1.5 KiB
ReStructuredText
.. Permission is granted to copy, distribute and/or modify this
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.. document under the terms of the GNU Free Documentation License,
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.. Version 1.1 or any later version published by the Free Software
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.. Foundation, with no Invariant Sections, no Front-Cover Texts
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.. and no Back-Cover Texts. A copy of the license is included at
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.. Documentation/userspace-api/media/fdl-appendix.rst.
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..
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.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
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.. _func-munmap:
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*************
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V4L2 munmap()
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*************
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Name
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====
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v4l2-munmap - Unmap device memory
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Synopsis
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========
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.. code-block:: c
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#include <unistd.h>
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#include <sys/mman.h>
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.. c:function:: int munmap( void *start, size_t length )
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:name: v4l2-munmap
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Arguments
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=========
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``start``
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Address of the mapped buffer as returned by the
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:ref:`mmap() <func-mmap>` function.
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``length``
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Length of the mapped buffer. This must be the same value as given to
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:ref:`mmap() <func-mmap>` and returned by the driver in the struct
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:c:type:`v4l2_buffer` ``length`` field for the
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single-planar API and in the struct
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:c:type:`v4l2_plane` ``length`` field for the
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multi-planar API.
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Description
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===========
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Unmaps a previously with the :ref:`mmap() <func-mmap>` function mapped
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buffer and frees it, if possible.
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Return Value
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============
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On success :ref:`munmap() <func-munmap>` returns 0, on failure -1 and the
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``errno`` variable is set appropriately:
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EINVAL
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The ``start`` or ``length`` is incorrect, or no buffers have been
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mapped yet.
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