diff options
Diffstat (limited to 'drivers/media')
| -rw-r--r-- | drivers/media/dvb-core/demux.h | 193 |
1 files changed, 190 insertions, 3 deletions
diff --git a/drivers/media/dvb-core/demux.h b/drivers/media/dvb-core/demux.h index 833191bcd810..54c3df38bb1b 100644 --- a/drivers/media/dvb-core/demux.h +++ b/drivers/media/dvb-core/demux.h @@ -202,10 +202,197 @@ struct dmx_frontend { #define DMX_FE_ENTRY(list) list_entry(list, struct dmx_frontend, connectivity_list) +/** + * struct dmx_demux - Structure that contains the demux capabilities and + * callbacks. + * + * @capabilities: Bitfield of capability flags + * + * @frontend: Front-end connected to the demux + * + * @priv: Pointer to private data of the API client + * + * @open: This function reserves the demux for use by the caller and, if + * necessary, initializes the demux. When the demux is no longer needed, + * the function close() should be called. It should be possible for + * multiple clients to access the demux at the same time. Thus, the + * function implementation should increment the demux usage count when + * open() is called and decrement it when close() is called. + * The @demux function parameter contains a pointer to the demux API and + * instance data. + * It returns + * 0 on success; + * -EUSERS, if maximum usage count was reached; + * -EINVAL, on bad parameter. + * + * @close: This function reserves the demux for use by the caller and, if + * necessary, initializes the demux. When the demux is no longer needed, + * the function close() should be called. It should be possible for + * multiple clients to access the demux at the same time. Thus, the + * function implementation should increment the demux usage count when + * open() is called and decrement it when close() is called. + * The @demux function parameter contains a pointer to the demux API and + * instance data. + * It returns + * 0 on success; + * -ENODEV, if demux was not in use + * -EINVAL, on bad parameter. + * + * @write: This function provides the demux driver with a memory buffer + * containing TS packets. Instead of receiving TS packets from the DVB + * front-end, the demux driver software will read packets from memory. + * Any clients of this demux with active TS, PES or Section filters will + * receive filtered data via the Demux callback API (see 0). The function + * returns when all the data in the buffer has been consumed by the demux. + * Demux hardware typically cannot read TS from memory. If this is the + * case, memory-based filtering has to be implemented entirely in software. + * The @demux function parameter contains a pointer to the demux API and + * instance data. + * The @buf function parameter contains a pointer to the TS data in + * kernel-space memory. + * The @count function parameter contains the length of the TS data. + * It returns + * 0 on success; + * -ENOSYS, if the command is not implemented; + * -EINVAL, on bad parameter. + * + * @allocate_ts_feed: Allocates a new TS feed, which is used to filter the TS + * packets carrying a certain PID. The TS feed normally corresponds to a + * hardware PID filter on the demux chip. + * The @demux function parameter contains a pointer to the demux API and + * instance data. + * The @feed function parameter contains a pointer to the TS feed API and + * instance data. + * The @callback function parameter contains a pointer to the callback + * function for passing received TS packet. + * It returns + * 0 on success; + * -EBUSY, if no more TS feeds is available; + * -ENOSYS, if the command is not implemented; + * -EINVAL, on bad parameter. + * + * @release_ts_feed: Releases the resources allocated with allocate_ts_feed(). + * Any filtering in progress on the TS feed should be stopped before + * calling this function. + * The @demux function parameter contains a pointer to the demux API and + * instance data. + * The @feed function parameter contains a pointer to the TS feed API and + * instance data. + * It returns + * 0 on success; + * -EINVAL on bad parameter. + * + * @allocate_section_feed: Allocates a new section feed, i.e. a demux resource + * for filtering and receiving sections. On platforms with hardware + * support for section filtering, a section feed is directly mapped to + * the demux HW. On other platforms, TS packets are first PID filtered in + * hardware and a hardware section filter then emulated in software. The + * caller obtains an API pointer of type dmx_section_feed_t as an out + * parameter. Using this API the caller can set filtering parameters and + * start receiving sections. + * The @demux function parameter contains a pointer to the demux API and + * instance data. + * The @feed function parameter contains a pointer to the TS feed API and + * instance data. + * The @callback function parameter contains a pointer to the callback + * function for passing received TS packet. + * It returns + * 0 on success; + * -EBUSY, if no more TS feeds is available; + * -ENOSYS, if the command is not implemented; + * -EINVAL, on bad parameter. + * + * @release_section_feed: Releases the resources allocated with + * allocate_section_feed(), including allocated filters. Any filtering in + * progress on the section feed should be stopped before calling this + * function. + * The @demux function parameter contains a pointer to the demux API and + * instance data. + * The @feed function parameter contains a pointer to the TS feed API and + * instance data. + * It returns + * 0 on success; + * -EINVAL, on bad parameter. + * + * @add_frontend: Registers a connectivity between a demux and a front-end, + * i.e., indicates that the demux can be connected via a call to + * connect_frontend() to use the given front-end as a TS source. The + * client of this function has to allocate dynamic or static memory for + * the frontend structure and initialize its fields before calling this + * function. This function is normally called during the driver + * initialization. The caller must not free the memory of the frontend + * struct before successfully calling remove_frontend(). + * The @demux function parameter contains a pointer to the demux API and + * instance data. + * The @frontend function parameter contains a pointer to the front-end + * instance data. + * It returns + * 0 on success; + * -EEXIST, if a front-end with the same value of the id field + * already registered; + * -EINUSE, if the demux is in use; + * -ENOMEM, if no more front-ends can be added; + * -EINVAL, on bad parameter. + * + * @remove_frontend: Indicates that the given front-end, registered by a call + * to add_frontend(), can no longer be connected as a TS source by this + * demux. The function should be called when a front-end driver or a demux + * driver is removed from the system. If the front-end is in use, the + * function fails with the return value of -EBUSY. After successfully + * calling this function, the caller can free the memory of the frontend + * struct if it was dynamically allocated before the add_frontend() + * operation. + * The @demux function parameter contains a pointer to the demux API and + * instance data. + * The @frontend function parameter contains a pointer to the front-end + * instance data. + * It returns + * 0 on success; + * -EBUSY, if the front-end is in use, i.e. a call to + * connect_frontend() has not been followed by a call to + * disconnect_frontend(); + * -EINVAL, on bad parameter. + * + * @get_frontends: Provides the APIs of the front-ends that have been + * registered for this demux. Any of the front-ends obtained with this + * call can be used as a parameter for connect_frontend(). The include + * file demux.h contains the macro DMX_FE_ENTRY() for converting an + * element of the generic type struct list_head* to the type + * dmx_frontend_t*. The caller must not free the memory of any of the + * elements obtained via this function call. + * The @demux function parameter contains a pointer to the demux API and + * instance data. + * It returns a struct list_head pointer to the list of front-end + * interfaces, or NULL in the case of an empty list. + * + * @connect_frontend: Connects the TS output of the front-end to the input of + * the demux. A demux can only be connected to a front-end registered to + * the demux with the function add_frontend(). It may or may not be + * possible to connect multiple demuxes to the same front-end, depending + * on the capabilities of the HW platform. When not used, the front-end + * should be released by calling disconnect_frontend(). + * The @demux function parameter contains a pointer to the demux API and + * instance data. + * The @frontend function parameter contains a pointer to the front-end + * instance data. + * It returns + * 0 on success; + * -EBUSY, if the front-end is in use; + * -EINVAL, on bad parameter. + * + * @disconnect_frontend: Disconnects the demux and a front-end previously + * connected by a connect_frontend() call. + * The @demux function parameter contains a pointer to the demux API and + * instance data. + * It returns + * 0 on success; + * -EINVAL on bad parameter. + */ + struct dmx_demux { - u32 capabilities; /* Bitfield of capability flags */ - struct dmx_frontend* frontend; /* Front-end connected to the demux */ - void* priv; /* Pointer to private data of the API client */ + u32 capabilities; + struct dmx_frontend* frontend; + void* priv; int (*open) (struct dmx_demux* demux); int (*close) (struct dmx_demux* demux); int (*write) (struct dmx_demux* demux, const char __user *buf, size_t count); |