Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 144 insertions, 0 deletions

diff --git a/Documentation/media/uapi/mediactl/media-ioc-enum-links.rst b/Documentation/media/uapi/mediactl/media-ioc-enum-links.rst
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+.. -*- coding: utf-8; mode: rst -*-
+
+.. _media_ioc_enum_links:
+
+**************************
+ioctl MEDIA_IOC_ENUM_LINKS
+**************************
+
+Name
+====
+
+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
+
+
+Arguments
+=========
+
+``fd``
+    File descriptor returned by :ref:`open() <media-func-open>`.
+
+``argp``
+
+
+Description
+===========
+
+To enumerate pads and/or links for a given entity, applications set the
+entity field of a struct :c:type:`media_links_enum`
+structure and initialize the struct
+:c:type:`media_pad_desc` and struct
+:c:type:`media_link_desc` structure arrays pointed by
+the ``pads`` and ``links`` fields. They then call the
+MEDIA_IOC_ENUM_LINKS ioctl with a pointer to this structure.
+
+If the ``pads`` field is not NULL, the driver fills the ``pads`` array
+with information about the entity's pads. The array must have enough
+room to store all the entity's pads. The number of pads can be retrieved
+with :ref:`MEDIA_IOC_ENUM_ENTITIES`.
+
+If the ``links`` field is not NULL, the driver fills the ``links`` array
+with information about the entity's outbound links. The array must have
+enough room to store all the entity's outbound links. The number of
+outbound links can be retrieved with :ref:`MEDIA_IOC_ENUM_ENTITIES`.
+
+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}|
+
+.. flat-table:: struct media_links_enum
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    *  -  __u32
+       -  ``entity``
+       -  Entity id, set by the application.
+
+    *  -  struct :c:type:`media_pad_desc`
+       -  \*\ ``pads``
+       -  Pointer to a pads array allocated by the application. Ignored if
+	  NULL.
+
+    *  -  struct :c:type:`media_link_desc`
+       -  \*\ ``links``
+       -  Pointer to a links array allocated by the application. Ignored if
+	  NULL.
+
+
+.. c:type:: media_pad_desc
+
+.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
+
+.. flat-table:: struct media_pad_desc
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    *  -  __u32
+       -  ``entity``
+       -  ID of the entity this pad belongs to.
+
+    *  -  __u16
+       -  ``index``
+       -  Pad index, starts at 0.
+
+    *  -  __u32
+       -  ``flags``
+       -  Pad flags, see :ref:`media-pad-flag` for more details.
+
+    *  -  __u32
+       -  ``reserved[2]``
+       -  Reserved for future extensions. Drivers and applications must set
+          the array to zero.
+
+
+
+.. c:type:: media_link_desc
+
+.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}|
+
+.. flat-table:: struct media_link_desc
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    *  -  struct :c:type:`media_pad_desc`
+       -  ``source``
+       -  Pad at the origin of this link.
+
+    *  -  struct :c:type:`media_pad_desc`
+       -  ``sink``
+       -  Pad at the target of this link.
+
+    *  -  __u32
+       -  ``flags``
+       -  Link flags, see :ref:`media-link-flag` for more details.
+
+    *  -  __u32
+       -  ``reserved[4]``
+       -  Reserved for future extensions. Drivers and applications must set
+          the array to zero.
+
+
+Return Value
+============
+
+On success 0 is returned, on error -1 and the ``errno`` variable is set
+appropriately. The generic error codes are described at the
+:ref:`Generic Error Codes <gen-errors>` chapter.
+
+EINVAL
+    The struct :c:type:`media_links_enum` ``id``
+    references a non-existing entity.