From 6128a68dbc0f5032fe9e55fbe5a712e713315ffd Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Wed, 20 Sep 2017 09:08:20 -0400 Subject: media: dvb_demux.h: document functions The functions used on dvb_demux.h are largely used on DVB drivers. Yet, none of them are documented. No functional changes. Signed-off-by: Mauro Carvalho Chehab --- drivers/media/dvb-core/dvb_demux.h | 106 +++++++++++++++++++++++++++++++++++-- 1 file changed, 103 insertions(+), 3 deletions(-) (limited to 'drivers/media') diff --git a/drivers/media/dvb-core/dvb_demux.h b/drivers/media/dvb-core/dvb_demux.h index ed136836ab6e..9a77be02cbb1 100644 --- a/drivers/media/dvb-core/dvb_demux.h +++ b/drivers/media/dvb-core/dvb_demux.h @@ -232,13 +232,113 @@ struct dvb_demux { int recording; }; -int dvb_dmx_init(struct dvb_demux *dvbdemux); -void dvb_dmx_release(struct dvb_demux *dvbdemux); -void dvb_dmx_swfilter_packets(struct dvb_demux *dvbdmx, const u8 *buf, +/** + * dvb_dmx_init - initialize a digital TV demux struct. + * + * @demux: &struct dvb_demux to be initialized. + * + * Before being able to register a digital TV demux struct, drivers + * should call this routine. On its typical usage, some fields should + * be initialized at the driver before calling it. + * + * A typical usecase is:: + * + * dvb->demux.dmx.capabilities = + * DMX_TS_FILTERING | DMX_SECTION_FILTERING | + * DMX_MEMORY_BASED_FILTERING; + * dvb->demux.priv = dvb; + * dvb->demux.filternum = 256; + * dvb->demux.feednum = 256; + * dvb->demux.start_feed = driver_start_feed; + * dvb->demux.stop_feed = driver_stop_feed; + * ret = dvb_dmx_init(&dvb->demux); + * if (ret < 0) + * return ret; + */ +int dvb_dmx_init(struct dvb_demux *demux); + +/** + * dvb_dmx_release - releases a digital TV demux internal buffers. + * + * @demux: &struct dvb_demux to be released. + * + * The DVB core internally allocates data at @demux. This routine + * releases those data. Please notice that the struct itelf is not + * released, as it can be embedded on other structs. + */ +void dvb_dmx_release(struct dvb_demux *demux); + +/** + * dvb_dmx_swfilter_packets - use dvb software filter for a buffer with + * multiple MPEG-TS packets with 188 bytes each. + * + * @demux: pointer to &struct dvb_demux + * @buf: buffer with data to be filtered + * @count: number of MPEG-TS packets with size of 188. + * + * The routine will discard a DVB packet that don't start with 0x47. + * + * Use this routine if the DVB demux fills MPEG-TS buffers that are + * already aligned. + * + * NOTE: The @buf size should have size equal to ``count * 188``. + */ +void dvb_dmx_swfilter_packets(struct dvb_demux *demux, const u8 *buf, size_t count); + +/** + * dvb_dmx_swfilter - use dvb software filter for a buffer with + * multiple MPEG-TS packets with 188 bytes each. + * + * @demux: pointer to &struct dvb_demux + * @buf: buffer with data to be filtered + * @count: number of MPEG-TS packets with size of 188. + * + * If a DVB packet doesn't start with 0x47, it will seek for the first + * byte that starts with 0x47. + * + * Use this routine if the DVB demux fill buffers that may not start with + * a packet start mark (0x47). + * + * NOTE: The @buf size should have size equal to ``count * 188``. + */ void dvb_dmx_swfilter(struct dvb_demux *demux, const u8 *buf, size_t count); + +/** + * dvb_dmx_swfilter_204 - use dvb software filter for a buffer with + * multiple MPEG-TS packets with 204 bytes each. + * + * @demux: pointer to &struct dvb_demux + * @buf: buffer with data to be filtered + * @count: number of MPEG-TS packets with size of 204. + * + * If a DVB packet doesn't start with 0x47, it will seek for the first + * byte that starts with 0x47. + * + * Use this routine if the DVB demux fill buffers that may not start with + * a packet start mark (0x47). + * + * NOTE: The @buf size should have size equal to ``count * 204``. + */ void dvb_dmx_swfilter_204(struct dvb_demux *demux, const u8 *buf, size_t count); + +/** + * dvb_dmx_swfilter_raw - make the raw data available to userspace without + * filtering + * + * @demux: pointer to &struct dvb_demux + * @buf: buffer with data + * @count: number of packets to be passed. The actual size of each packet + * depends on the &dvb_demux->feed->cb.ts logic. + * + * Use it if the driver needs to deliver the raw payload to userspace without + * passing through the kernel demux. That is meant to support some + * delivery systems that aren't based on MPEG-TS. + * + * This function relies on &dvb_demux->feed->cb.ts to actually handle the + * buffer. + */ void dvb_dmx_swfilter_raw(struct dvb_demux *demux, const u8 *buf, size_t count); -- cgit v1.2.3