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| -rw-r--r-- | Documentation/media/uapi/dvb/dmx-expbuf.rst | 90 | ||||
| -rw-r--r-- | Documentation/media/uapi/dvb/dmx-qbuf.rst | 85 | ||||
| -rw-r--r-- | Documentation/media/uapi/dvb/dmx-querybuf.rst | 65 | ||||
| -rw-r--r-- | Documentation/media/uapi/dvb/dmx-reqbufs.rst | 76 | ||||
| -rw-r--r-- | Documentation/media/uapi/dvb/dmx_fcalls.rst | 4 |
5 files changed, 320 insertions, 0 deletions
diff --git a/Documentation/media/uapi/dvb/dmx-expbuf.rst b/Documentation/media/uapi/dvb/dmx-expbuf.rst new file mode 100644 index 000000000000..51df34c6fb59 --- /dev/null +++ b/Documentation/media/uapi/dvb/dmx-expbuf.rst @@ -0,0 +1,90 @@ +.. _DMX_EXPBUF: + +**************** +ioctl DMX_EXPBUF +**************** + +Name +==== + +DMX_EXPBUF - Export a buffer as a DMABUF file descriptor. + +.. warning:: this API is still experimental + + +Synopsis +======== + +.. c:function:: int ioctl( int fd, DMX_EXPBUF, struct dmx_exportbuffer *argp ) + :name: DMX_EXPBUF + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <dmx_fopen>`. + +``argp`` + Pointer to struct :c:type:`dmx_exportbuffer`. + + +Description +=========== + +This ioctl is an extension to the memory mapping I/O method. +It can be used to export a buffer as a DMABUF file at any time after +buffers have been allocated with the :ref:`DMX_REQBUFS` ioctl. + +The ``reserved`` array must be zeroed before calling it. + +To export a buffer, applications fill struct :c:type:`dmx_exportbuffer`. +Applications must set the ``index`` field. Valid index numbers +range from zero to the number of buffers allocated with :ref:`DMX_REQBUFS` +(struct :c:type:`dmx_requestbuffers` ``count``) minus one. +Additional flags may be posted in the ``flags`` field. Refer to a manual +for open() for details. Currently only O_CLOEXEC, O_RDONLY, O_WRONLY, +and O_RDWR are supported. +All other fields must be set to zero. In the +case of multi-planar API, every plane is exported separately using +multiple :ref:`DMX_EXPBUF` calls. + +After calling :ref:`DMX_EXPBUF` the ``fd`` field will be set by a +driver, on success. This is a DMABUF file descriptor. The application may +pass it to other DMABUF-aware devices. It is recommended to close a DMABUF +file when it is no longer used to allow the associated memory to be reclaimed. + + +Examples +======== + + +.. code-block:: c + + int buffer_export(int v4lfd, enum dmx_buf_type bt, int index, int *dmafd) + { + struct dmx_exportbuffer expbuf; + + memset(&expbuf, 0, sizeof(expbuf)); + expbuf.type = bt; + expbuf.index = index; + if (ioctl(v4lfd, DMX_EXPBUF, &expbuf) == -1) { + perror("DMX_EXPBUF"); + return -1; + } + + *dmafd = expbuf.fd; + + return 0; + } + +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 + A queue is not in MMAP mode or DMABUF exporting is not supported or + ``flags`` or ``index`` fields are invalid. diff --git a/Documentation/media/uapi/dvb/dmx-qbuf.rst b/Documentation/media/uapi/dvb/dmx-qbuf.rst new file mode 100644 index 000000000000..b20b8153d48d --- /dev/null +++ b/Documentation/media/uapi/dvb/dmx-qbuf.rst @@ -0,0 +1,85 @@ +.. _DMX_QBUF: + +************************* +ioctl DMX_QBUF, DMX_DQBUF +************************* + +Name +==== + +DMX_QBUF - DMX_DQBUF - Exchange a buffer with the driver + +.. warning:: this API is still experimental + + +Synopsis +======== + +.. c:function:: int ioctl( int fd, DMX_QBUF, struct dmx_buffer *argp ) + :name: DMX_QBUF + +.. c:function:: int ioctl( int fd, DMX_DQBUF, struct dmx_buffer *argp ) + :name: DMX_DQBUF + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <dmx_fopen>`. + +``argp`` + Pointer to struct :c:type:`dmx_buffer`. + + +Description +=========== + +Applications call the ``DMX_QBUF`` ioctl to enqueue an empty +(capturing) or filled (output) buffer in the driver's incoming queue. +The semantics depend on the selected I/O method. + +To enqueue a buffer applications set the ``index`` field. Valid index +numbers range from zero to the number of buffers allocated with +:ref:`DMX_REQBUFS` (struct :c:type:`dmx_requestbuffers` ``count``) minus +one. The contents of the struct :c:type:`dmx_buffer` returned +by a :ref:`DMX_QUERYBUF` ioctl will do as well. + +The and ``reserved`` field must be set to 0. + +When ``DMX_QBUF`` is called with a pointer to this structure, it locks the +memory pages of the buffer in physical memory, so they cannot be swapped +out to disk. Buffers remain locked until dequeued, until the +the device is closed. + +Applications call the ``DMX_DQBUF`` ioctl to dequeue a filled +(capturing) buffer from the driver's outgoing queue. They just set the ``reserved`` field array to zero. When ``DMX_DQBUF`` is called with a +pointer to this structure, the driver fills the remaining fields or +returns an error code. + +By default ``DMX_DQBUF`` blocks when no buffer is in the outgoing +queue. When the ``O_NONBLOCK`` flag was given to the +:ref:`open() <dmx_fopen>` function, ``DMX_DQBUF`` returns +immediately with an ``EAGAIN`` error code when no buffer is available. + +The struct :c:type:`dmx_buffer` structure is specified in +:ref:`buffer`. + + +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. + +EAGAIN + Non-blocking I/O has been selected using ``O_NONBLOCK`` and no + buffer was in the outgoing queue. + +EINVAL + The ``index`` is out of bounds, or no buffers have been allocated yet. + +EIO + ``DMX_DQBUF`` failed due to an internal error. Can also indicate + temporary problems like signal loss or CRC errors. diff --git a/Documentation/media/uapi/dvb/dmx-querybuf.rst b/Documentation/media/uapi/dvb/dmx-querybuf.rst new file mode 100644 index 000000000000..46a50f191b10 --- /dev/null +++ b/Documentation/media/uapi/dvb/dmx-querybuf.rst @@ -0,0 +1,65 @@ +.. _DMX_QUERYBUF: + +****************** +ioctl DMX_QUERYBUF +****************** + +Name +==== + +DMX_QUERYBUF - Query the status of a buffer + +.. warning:: this API is still experimental + + +Synopsis +======== + +.. c:function:: int ioctl( int fd, DMX_QUERYBUF, struct dvb_buffer *argp ) + :name: DMX_QUERYBUF + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <dmx_fopen>`. + +``argp`` + Pointer to struct :c:type:`dvb_buffer`. + + +Description +=========== + +This ioctl is part of the mmap streaming I/O method. It can +be used to query the status of a buffer at any time after buffers have +been allocated with the :ref:`DMX_REQBUFS` ioctl. + +The ``reserved`` array must be zeroed before calling it. + +Applications set the ``index`` field. Valid index numbers range from zero +to the number of buffers allocated with :ref:`DMX_REQBUFS` +(struct :c:type:`dvb_requestbuffers` ``count``) minus one. + +After calling :ref:`DMX_QUERYBUF` with a pointer to this structure, +drivers return an error code or fill the rest of the structure. + +On success, the ``offset`` will contain the offset of the buffer from the +start of the device memory, the ``length`` field its size, and the +``bytesused`` the number of bytes occupied by data in the buffer (payload). + +Return Value +============ + +On success 0 is returned, the ``offset`` will contain the offset of the +buffer from the start of the device memory, the ``length`` field its size, +and the ``bytesused`` the number of bytes occupied by data in the buffer +(payload). + +On error it returns -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 ``index`` is out of bounds. diff --git a/Documentation/media/uapi/dvb/dmx-reqbufs.rst b/Documentation/media/uapi/dvb/dmx-reqbufs.rst new file mode 100644 index 000000000000..0749623d9d83 --- /dev/null +++ b/Documentation/media/uapi/dvb/dmx-reqbufs.rst @@ -0,0 +1,76 @@ +.. _DMX_REQBUFS: + +***************** +ioctl DMX_REQBUFS +***************** + +Name +==== + +DMX_REQBUFS - Initiate Memory Mapping and/or DMA buffer I/O + +.. warning:: this API is still experimental + + +Synopsis +======== + +.. c:function:: int ioctl( int fd, DMX_REQBUFS, struct dmx_requestbuffers *argp ) + :name: DMX_REQBUFS + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <dmx_fopen>`. + +``argp`` + Pointer to struct :c:type:`dmx_requestbuffers`. + +Description +=========== + +This ioctl is used to initiate a memory mapped or DMABUF based demux I/O. + +Memory mapped buffers are located in device memory and must be allocated +with this ioctl before they can be mapped into the application's address +space. User buffers are allocated by applications themselves, and this +ioctl is merely used to switch the driver into user pointer I/O mode and +to setup some internal structures. Similarly, DMABUF buffers are +allocated by applications through a device driver, and this ioctl only +configures the driver into DMABUF I/O mode without performing any direct +allocation. + +The ``reserved`` array must be zeroed before calling it. + +To allocate device buffers applications initialize all fields of the +struct :c:type:`dmx_requestbuffers` structure. They set the ``count`` field +to the desired number of buffers, and ``size`` to the size of each +buffer. + +When the ioctl is called with a pointer to this structure, the driver will +attempt to allocate the requested number of buffers and it stores the actual +number allocated in the ``count`` field. The ``count`` can be smaller than the number requested, even zero, when the driver runs out of free memory. A larger +number is also possible when the driver requires more buffers to +function correctly. The actual allocated buffer size can is returned +at ``size``, and can be smaller than what's requested. + +When this I/O method is not supported, the ioctl returns an ``EOPNOTSUPP`` +error code. + +Applications can call :ref:`DMX_REQBUFS` again to change the number of +buffers, however this cannot succeed when any buffers are still mapped. +A ``count`` value of zero frees all buffers, after aborting or finishing +any DMA in progress. + + +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. + +EOPNOTSUPP + The the requested I/O method is not supported. diff --git a/Documentation/media/uapi/dvb/dmx_fcalls.rst b/Documentation/media/uapi/dvb/dmx_fcalls.rst index db19df6dbf70..4c391cf2554f 100644 --- a/Documentation/media/uapi/dvb/dmx_fcalls.rst +++ b/Documentation/media/uapi/dvb/dmx_fcalls.rst @@ -24,3 +24,7 @@ Demux Function Calls dmx-get-pes-pids dmx-add-pid dmx-remove-pid + dmx-reqbufs + dmx-querybuf + dmx-expbuf + dmx-qbuf |