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[media] dtv-core.rst: move DTV ringbuffer notes to kAPI doc 

Instead of keeping those notes at the file on a non-structured
way, move them to dtv-core.rst, using the proper ReST tags.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Mauro Carvalho Chehab 2016-08-29 08:39:32 -03:00
parent ff54c19d8e
commit b6df512a9f
2 changed files with 36 additions and 30 deletions
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38
Documentation/media/kapi/dtv-core.rst
View File

@ -6,8 +6,6 @@ Digital TV Common functions
.. kernel-doc:: drivers/media/dvb-core/dvb_math.h
.. kernel-doc:: drivers/media/dvb-core/dvb_ringbuffer.h
.. kernel-doc:: drivers/media/dvb-core/dvbdev.h
@ -18,6 +16,42 @@ Digital TV Common functions
.. kernel-doc:: drivers/media/dvb-core/dvbdev.h
:export: drivers/media/dvb-core/dvbdev.c
Digital TV Ring buffer
----------------------
Those routines implement ring buffers used to handle digital TV data and
copy it from/to userspace.
.. note::
1) For performance reasons read and write routines don't check buffer sizes
and/or number of bytes free/available. This has to be done before these
routines are called. For example:
.. code-block:: c
/* write @buflen: bytes */
free = dvb_ringbuffer_free(rbuf);
if (free >= buflen)
count = dvb_ringbuffer_write(rbuf, buffer, buflen);
else
/* do something */
/* read min. 1000, max. @bufsize: bytes */
avail = dvb_ringbuffer_avail(rbuf);
if (avail >= 1000)
count = dvb_ringbuffer_read(rbuf, buffer, min(avail, bufsize));
else
/* do something */
2) If there is exactly one reader and one writer, there is no need
to lock read or write operations.
Two or more readers must be locked against each other.
Flushing the buffer counts as a read operation.
Resetting the buffer counts as a read and write operation.
Two or more writers must be locked against each other.
.. kernel-doc:: drivers/media/dvb-core/dvb_ringbuffer.h
Digital TV Frontend kABI

28
drivers/media/dvb-core/dvb_ringbuffer.h
View File

@ -66,34 +66,6 @@ extern void dvb_ringbuffer_init(struct dvb_ringbuffer *rbuf, void *data,
*
* @rbuf: pointer to struct dvb_ringbuffer
*/
/*
* Notes:
* ------
* (1) For performance reasons read and write routines don't check buffer sizes
* and/or number of bytes free/available. This has to be done before these
* routines are called. For example:
*
* *** write @buflen: bytes ***
* free = dvb_ringbuffer_free(rbuf);
* if (free >= buflen)
* count = dvb_ringbuffer_write(rbuf, buffer, buflen);
* else
* ...
*
* *** read min. 1000, max. @bufsize: bytes ***
* avail = dvb_ringbuffer_avail(rbuf);
* if (avail >= 1000)
* count = dvb_ringbuffer_read(rbuf, buffer, min(avail, bufsize));
* else
* ...
*
* (2) If there is exactly one reader and one writer, there is no need
* to lock read or write operations.
* Two or more readers must be locked against each other.
* Flushing the buffer counts as a read operation.
* Resetting the buffer counts as a read and write operation.
* Two or more writers must be locked against each other.
*/
extern int dvb_ringbuffer_empty(struct dvb_ringbuffer *rbuf);
/**