.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
.. _media-func-close:
media-close - Close a media device
-
Synopsis
========
#include <unistd.h>
-
.. c:function:: int close( int fd )
- :name: mc-close
Arguments
=========
``fd``
- File descriptor returned by :c:func:`open() <mc-open>`.
-
+ File descriptor returned by :c:func:`open()`.
Description
===========
Closes the media device. Resources associated with the file descriptor
are freed. The device configuration remain unchanged.
-
Return Value
============
-:ref:`close() <media-func-close>` returns 0 on success. On error, -1 is returned, and
+:c:func:`close()` returns 0 on success. On error, -1 is returned, and
``errno`` is set appropriately. Possible error codes are:
EBADF
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
.. _media-func-ioctl:
media-ioctl - Control a media device
-
Synopsis
========
#include <sys/ioctl.h>
-
-.. c:function:: int ioctl( int fd, int request, void *argp )
- :name: mc-ioctl
+``int ioctl(int fd, int request, void *argp)``
Arguments
=========
``fd``
- File descriptor returned by :c:func:`open() <mc-open>`.
+ File descriptor returned by :c:func:`open()`.
``request``
Media ioctl request code as defined in the media.h header file, for
``argp``
Pointer to a request-specific structure.
-
Description
===========
requests, their respective function and parameters are specified in
:ref:`media-user-func`.
-
Return Value
============
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
.. _media-func-open:
media-open - Open a media device
-
Synopsis
========
#include <fcntl.h>
-
.. c:function:: int open( const char *device_name, int flags )
- :name: mc-open
Arguments
=========
Open flags. Access mode must be either ``O_RDONLY`` or ``O_RDWR``.
Other flags have no effect.
-
Description
===========
-To open a media device applications call :ref:`open() <media-func-open>` with the
+To open a media device applications call :c:func:`open()` with the
desired device name. The function has no side effects; the device
configuration remain unchanged.
configuration will result in an error, and ``errno`` will be set to
EBADF.
-
Return Value
============
-:ref:`open() <func-open>` returns the new file descriptor on success. On error,
+:c:func:`open()` returns the new file descriptor on success. On error,
-1 is returned, and ``errno`` is set appropriately. Possible error codes
are:
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
.. _media_ioc_device_info:
MEDIA_IOC_DEVICE_INFO - Query device information
-
Synopsis
========
-.. c:function:: int ioctl( int fd, MEDIA_IOC_DEVICE_INFO, struct media_device_info *argp )
- :name: MEDIA_IOC_DEVICE_INFO
+.. c:macro:: MEDIA_IOC_DEVICE_INFO
+``int ioctl(int fd, MEDIA_IOC_DEVICE_INFO, struct media_device_info *argp)``
Arguments
=========
``fd``
- File descriptor returned by :ref:`open() <media-func-open>`.
+ File descriptor returned by :c:func:`open()`.
``argp``
Pointer to struct :c:type:`media_device_info`.
-
Description
===========
fills the structure and returns the information to the application. The
ioctl never fails.
-
.. c:type:: media_device_info
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
:stub-columns: 0
:widths: 1 1 2
-
* - char
- ``driver``\ [16]
- Name of the driver implementing the media API as a NUL-terminated
- Reserved for future extensions. Drivers and applications must set
this array to zero.
-
The ``serial`` and ``bus_info`` fields can be used to distinguish
between multiple instances of otherwise identical hardware. The serial
number takes precedence when provided and can be assumed to be unique.
used instead. The ``bus_info`` field is guaranteed to be unique, but can
vary across reboots or device unplug/replug.
-
Return Value
============
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
.. _media_ioc_enum_entities:
MEDIA_IOC_ENUM_ENTITIES - Enumerate entities and their properties
-
Synopsis
========
-.. c:function:: int ioctl( int fd, MEDIA_IOC_ENUM_ENTITIES, struct media_entity_desc *argp )
- :name: MEDIA_IOC_ENUM_ENTITIES
+.. c:macro:: MEDIA_IOC_ENUM_ENTITIES
+``int ioctl(int fd, MEDIA_IOC_ENUM_ENTITIES, struct media_entity_desc *argp)``
Arguments
=========
``fd``
- File descriptor returned by :ref:`open() <media-func-open>`.
+ File descriptor returned by :c:func:`open()`.
``argp``
Pointer to struct :c:type:`media_entity_desc`.
-
Description
===========
enumerate entities by calling MEDIA_IOC_ENUM_ENTITIES with increasing
id's until they get an error.
-
.. c:type:: media_entity_desc
.. tabularcolumns:: |p{1.5cm}|p{1.7cm}|p{1.6cm}|p{1.5cm}|p{11.2cm}|
* - }
-
-
Return Value
============
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
.. _media_ioc_enum_links:
MEDIA_IOC_ENUM_LINKS - Enumerate all pads and links for a given entity
-
Synopsis
========
-.. c:function:: int ioctl( int fd, MEDIA_IOC_ENUM_LINKS, struct media_links_enum *argp )
- :name: MEDIA_IOC_ENUM_LINKS
+.. c:macro:: MEDIA_IOC_ENUM_LINKS
+``int ioctl(int fd, MEDIA_IOC_ENUM_LINKS, struct media_links_enum *argp)``
Arguments
=========
``fd``
- File descriptor returned by :ref:`open() <media-func-open>`.
+ File descriptor returned by :c:func:`open()`.
``argp``
Pointer to struct :c:type:`media_links_enum`.
-
Description
===========
Only forward links that originate at one of the entity's source pads are
returned during the enumeration process.
-
.. c:type:: media_links_enum
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
- Reserved for future extensions. Drivers and applications must set
the array to zero.
-
.. c:type:: media_pad_desc
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
the array to zero.
-
.. c:type:: media_link_desc
.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
- Reserved for future extensions. Drivers and applications must set
the array to zero.
-
Return Value
============
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
.. _media_ioc_g_topology:
MEDIA_IOC_G_TOPOLOGY - Enumerate the graph topology and graph element properties
-
Synopsis
========
-.. c:function:: int ioctl( int fd, MEDIA_IOC_G_TOPOLOGY, struct media_v2_topology *argp )
- :name: MEDIA_IOC_G_TOPOLOGY
+.. c:macro:: MEDIA_IOC_G_TOPOLOGY
+``int ioctl(int fd, MEDIA_IOC_G_TOPOLOGY, struct media_v2_topology *argp)``
Arguments
=========
``fd``
- File descriptor returned by :ref:`open() <media-func-open>`.
+ File descriptor returned by :c:func:`open()`.
``argp``
Pointer to struct :c:type:`media_v2_topology`.
-
Description
===========
converted to a 64-bits integer. It can be zero. if zero, the ioctl
won't store the links. It will just update ``num_links``
-
.. tabularcolumns:: |p{1.6cm}|p{3.2cm}|p{12.7cm}|
.. c:type:: media_v2_entity
- Reserved for future extensions. Drivers and applications must set
this array to zero.
-
.. tabularcolumns:: |p{1.6cm}|p{3.2cm}|p{12.7cm}|
.. c:type:: media_v2_interface
- Used only for device node interfaces. See
:c:type:`media_v2_intf_devnode` for details.
-
.. tabularcolumns:: |p{1.6cm}|p{3.2cm}|p{12.7cm}|
.. c:type:: media_v2_intf_devnode
- Reserved for future extensions. Drivers and applications must set
this array to zero.
-
.. tabularcolumns:: |p{1.6cm}|p{3.2cm}|p{12.7cm}|
.. c:type:: media_v2_link
- Reserved for future extensions. Drivers and applications must set
this array to zero.
-
Return Value
============
.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
.. _media_ioc_request_alloc:
MEDIA_IOC_REQUEST_ALLOC - Allocate a request
-
Synopsis
========
-.. c:function:: int ioctl( int fd, MEDIA_IOC_REQUEST_ALLOC, int *argp )
- :name: MEDIA_IOC_REQUEST_ALLOC
+.. c:macro:: MEDIA_IOC_REQUEST_ALLOC
+``int ioctl(int fd, MEDIA_IOC_REQUEST_ALLOC, int *argp)``
Arguments
=========
``fd``
- File descriptor returned by :ref:`open() <media-func-open>`.
+ File descriptor returned by :c:func:`open()`.
``argp``
Pointer to an integer.
-
Description
===========
for the request to complete.
The request will remain allocated until all the file descriptors associated
-with it are closed by :ref:`close() <request-func-close>` and the driver no
+with it are closed by :c:func:`close()` and the driver no
longer uses the request internally. See also
:ref:`here <media-request-life-time>` for more information.
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
.. _media_ioc_setup_link:
MEDIA_IOC_SETUP_LINK - Modify the properties of a link
-
Synopsis
========
-.. c:function:: int ioctl( int fd, MEDIA_IOC_SETUP_LINK, struct media_link_desc *argp )
- :name: MEDIA_IOC_SETUP_LINK
+.. c:macro:: MEDIA_IOC_SETUP_LINK
+``int ioctl(int fd, MEDIA_IOC_SETUP_LINK, struct media_link_desc *argp)``
Arguments
=========
``fd``
- File descriptor returned by :ref:`open() <media-func-open>`.
+ File descriptor returned by :c:func:`open()`.
``argp``
Pointer to struct :c:type:`media_link_desc`.
-
Description
===========
If the specified link can't be found the driver returns with an ``EINVAL``
error code.
-
Return Value
============
.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
.. _media_request_ioc_queue:
MEDIA_REQUEST_IOC_QUEUE - Queue a request
-
Synopsis
========
-.. c:function:: int ioctl( int request_fd, MEDIA_REQUEST_IOC_QUEUE )
- :name: MEDIA_REQUEST_IOC_QUEUE
+.. c:macro:: MEDIA_REQUEST_IOC_QUEUE
+``int ioctl(int request_fd, MEDIA_REQUEST_IOC_QUEUE)``
Arguments
=========
``request_fd``
File descriptor returned by :ref:`MEDIA_IOC_REQUEST_ALLOC`.
-
Description
===========
.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
.. _media_request_ioc_reinit:
MEDIA_REQUEST_IOC_REINIT - Re-initialize a request
-
Synopsis
========
-.. c:function:: int ioctl( int request_fd, MEDIA_REQUEST_IOC_REINIT )
- :name: MEDIA_REQUEST_IOC_REINIT
+.. c:macro:: MEDIA_REQUEST_IOC_REINIT
+``int ioctl(int request_fd, MEDIA_REQUEST_IOC_REINIT)``
Arguments
=========
request.
Re-initializing a request will clear any existing data from the request.
-This avoids having to :ref:`close() <request-func-close>` a completed
+This avoids having to :c:func:`close()` a completed
request and allocate a new request. Instead the completed request can just
be re-initialized and it is ready to be used again.
.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
.. _media-request-api:
Setting the same control through a request and also directly can lead to
undefined behavior!
-User-space can :ref:`poll() <request-func-poll>` a request file descriptor in
+User-space can :c:func:`poll()` a request file descriptor in
order to wait until the request completes. A request is considered complete
once all its associated buffers are available for dequeuing and all the
associated controls have been updated with the values at the time of completion.
-------------------------
Finally, a completed request can either be discarded or be reused. Calling
-:ref:`close() <request-func-close>` on a request file descriptor will make
+:c:func:`close()` on a request file descriptor will make
that file descriptor unusable and the request will be freed once it is no
longer in use by the kernel. That is, if the request is queued and then the
file descriptor is closed, then it won't be freed until the driver completed
.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC.request
.. _request-func-close:
request-close - Close a request file descriptor
-
Synopsis
========
#include <unistd.h>
-
.. c:function:: int close( int fd )
- :name: req-close
Arguments
=========
``fd``
File descriptor returned by :ref:`MEDIA_IOC_REQUEST_ALLOC`.
-
Description
===========
and the driver has completed the request.
See :ref:`here <media-request-life-time>` for more information.
-
Return Value
============
-:ref:`close() <request-func-close>` returns 0 on success. On error, -1 is
+:c:func:`close()` returns 0 on success. On error, -1 is
returned, and ``errno`` is set appropriately. Possible error codes are:
EBADF
.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
.. _request-func-ioctl:
request-ioctl - Control a request file descriptor
-
Synopsis
========
#include <sys/ioctl.h>
-
-.. c:function:: int ioctl( int fd, int cmd, void *argp )
- :name: req-ioctl
+``int ioctl(int fd, int cmd, void *argp)``
Arguments
=========
``argp``
Pointer to a request-specific structure.
-
Description
===========
commands, their respective function and parameters are specified in
:ref:`media-user-func`.
-
Return Value
============
.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later
+.. c:namespace:: MC
.. _request-func-poll:
request-poll - Wait for some event on a file descriptor
-
Synopsis
========
#include <sys/poll.h>
-
.. c:function:: int poll( struct pollfd *ufds, unsigned int nfds, int timeout )
- :name: request-poll
Arguments
=========
``timeout``
Timeout to wait for events
-
Description
===========
-With the :c:func:`poll() <request-func-poll>` function applications can wait
+With the :c:func:`poll()` function applications can wait
for a request to complete.
-On success :c:func:`poll() <request-func-poll>` returns the number of file
+On success :c:func:`poll()` returns the number of file
descriptors that have been selected (that is, file descriptors for which the
``revents`` field of the respective struct :c:type:`pollfd`
is non-zero). Request file descriptor set the ``POLLPRI`` flag in ``revents``
Attempting to poll for a request that is not yet queued will
set the ``POLLERR`` flag in ``revents``.
-
Return Value
============
-On success, :c:func:`poll() <request-func-poll>` returns the number of
+On success, :c:func:`poll()` returns the number of
structures which have non-zero ``revents`` fields, or zero if the call
timed out. On error -1 is returned, and the ``errno`` variable is set
appropriately:
projects / platform / kernel / linux-rpi.git / commitdiff