linux/drivers/media/dvb-core/demux.h
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   1/*
   2 * demux.h
   3 *
   4 * Copyright (c) 2002 Convergence GmbH
   5 *
   6 * based on code:
   7 * Copyright (c) 2000 Nokia Research Center
   8 *                    Tampere, FINLAND
   9 *
  10 * This program is free software; you can redistribute it and/or
  11 * modify it under the terms of the GNU Lesser General Public License
  12 * as published by the Free Software Foundation; either version 2.1
  13 * of the License, or (at your option) any later version.
  14 *
  15 * This program is distributed in the hope that it will be useful,
  16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 * GNU General Public License for more details.
  19 *
  20 * You should have received a copy of the GNU Lesser General Public License
  21 * along with this program; if not, write to the Free Software
  22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  23 *
  24 */
  25
  26#ifndef __DEMUX_H
  27#define __DEMUX_H
  28
  29#include <linux/types.h>
  30#include <linux/errno.h>
  31#include <linux/list.h>
  32#include <linux/time.h>
  33#include <linux/dvb/dmx.h>
  34
  35/**
  36 * DOC: Digital TV Demux
  37 *
  38 * The Kernel Digital TV Demux kABI defines a driver-internal interface for
  39 * registering low-level, hardware specific driver to a hardware independent
  40 * demux layer. It is only of interest for Digital TV device driver writers.
  41 * The header file for this kABI is named demux.h and located in
  42 * drivers/media/dvb-core.
  43 *
  44 * The demux kABI should be implemented for each demux in the system. It is
  45 * used to select the TS source of a demux and to manage the demux resources.
  46 * When the demux client allocates a resource via the demux kABI, it receives
  47 * a pointer to the kABI of that resource.
  48 *
  49 * Each demux receives its TS input from a DVB front-end or from memory, as
  50 * set via this demux kABI. In a system with more than one front-end, the kABI
  51 * can be used to select one of the DVB front-ends as a TS source for a demux,
  52 * unless this is fixed in the HW platform.
  53 *
  54 * The demux kABI only controls front-ends regarding to their connections with
  55 * demuxes; the kABI used to set the other front-end parameters, such as
  56 * tuning, are devined via the Digital TV Frontend kABI.
  57 *
  58 * The functions that implement the abstract interface demux should be defined
  59 * static or module private and registered to the Demux core for external
  60 * access. It is not necessary to implement every function in the struct
  61 * &dmx_demux. For example, a demux interface might support Section filtering,
  62 * but not PES filtering. The kABI client is expected to check the value of any
  63 * function pointer before calling the function: the value of NULL means
  64 * that the function is not available.
  65 *
  66 * Whenever the functions of the demux API modify shared data, the
  67 * possibilities of lost update and race condition problems should be
  68 * addressed, e.g. by protecting parts of code with mutexes.
  69 *
  70 * Note that functions called from a bottom half context must not sleep.
  71 * Even a simple memory allocation without using %GFP_ATOMIC can result in a
  72 * kernel thread being put to sleep if swapping is needed. For example, the
  73 * Linux Kernel calls the functions of a network device interface from a
  74 * bottom half context. Thus, if a demux kABI function is called from network
  75 * device code, the function must not sleep.
  76 */
  77
  78/*
  79 * Common definitions
  80 */
  81
  82/*
  83 * DMX_MAX_FILTER_SIZE: Maximum length (in bytes) of a section/PES filter.
  84 */
  85
  86#ifndef DMX_MAX_FILTER_SIZE
  87#define DMX_MAX_FILTER_SIZE 18
  88#endif
  89
  90/*
  91 * DMX_MAX_SECFEED_SIZE: Maximum length (in bytes) of a private section feed
  92 * filter.
  93 */
  94
  95#ifndef DMX_MAX_SECTION_SIZE
  96#define DMX_MAX_SECTION_SIZE 4096
  97#endif
  98#ifndef DMX_MAX_SECFEED_SIZE
  99#define DMX_MAX_SECFEED_SIZE (DMX_MAX_SECTION_SIZE + 188)
 100#endif
 101
 102/*
 103 * TS packet reception
 104 */
 105
 106/**
 107 * enum ts_filter_type - filter type bitmap for dmx_ts_feed.set()
 108 *
 109 * @TS_PACKET:          Send TS packets (188 bytes) to callback (default).
 110 * @TS_PAYLOAD_ONLY:    In case TS_PACKET is set, only send the TS payload
 111 *                      (<=184 bytes per packet) to callback
 112 * @TS_DECODER:         Send stream to built-in decoder (if present).
 113 * @TS_DEMUX:           In case TS_PACKET is set, send the TS to the demux
 114 *                      device, not to the dvr device
 115 */
 116enum ts_filter_type {
 117        TS_PACKET = 1,
 118        TS_PAYLOAD_ONLY = 2,
 119        TS_DECODER = 4,
 120        TS_DEMUX = 8,
 121};
 122
 123/**
 124 * struct dmx_ts_feed - Structure that contains a TS feed filter
 125 *
 126 * @is_filtering:       Set to non-zero when filtering in progress
 127 * @parent:             pointer to struct dmx_demux
 128 * @priv:               pointer to private data of the API client
 129 * @set:                sets the TS filter
 130 * @start_filtering:    starts TS filtering
 131 * @stop_filtering:     stops TS filtering
 132 *
 133 * A TS feed is typically mapped to a hardware PID filter on the demux chip.
 134 * Using this API, the client can set the filtering properties to start/stop
 135 * filtering TS packets on a particular TS feed.
 136 */
 137struct dmx_ts_feed {
 138        int is_filtering;
 139        struct dmx_demux *parent;
 140        void *priv;
 141        int (*set)(struct dmx_ts_feed *feed,
 142                   u16 pid,
 143                   int type,
 144                   enum dmx_ts_pes pes_type,
 145                   size_t circular_buffer_size,
 146                   struct timespec timeout);
 147        int (*start_filtering)(struct dmx_ts_feed *feed);
 148        int (*stop_filtering)(struct dmx_ts_feed *feed);
 149};
 150
 151/*
 152 * Section reception
 153 */
 154
 155/**
 156 * struct dmx_section_filter - Structure that describes a section filter
 157 *
 158 * @filter_value: Contains up to 16 bytes (128 bits) of the TS section header
 159 *                that will be matched by the section filter
 160 * @filter_mask:  Contains a 16 bytes (128 bits) filter mask with the bits
 161 *                specified by @filter_value that will be used on the filter
 162 *                match logic.
 163 * @filter_mode:  Contains a 16 bytes (128 bits) filter mode.
 164 * @parent:       Pointer to struct dmx_section_feed.
 165 * @priv:         Pointer to private data of the API client.
 166 *
 167 *
 168 * The @filter_mask controls which bits of @filter_value are compared with
 169 * the section headers/payload. On a binary value of 1 in filter_mask, the
 170 * corresponding bits are compared. The filter only accepts sections that are
 171 * equal to filter_value in all the tested bit positions.
 172 */
 173struct dmx_section_filter {
 174        u8 filter_value[DMX_MAX_FILTER_SIZE];
 175        u8 filter_mask[DMX_MAX_FILTER_SIZE];
 176        u8 filter_mode[DMX_MAX_FILTER_SIZE];
 177        struct dmx_section_feed *parent; /* Back-pointer */
 178        void *priv; /* Pointer to private data of the API client */
 179};
 180
 181/**
 182 * struct dmx_section_feed - Structure that contains a section feed filter
 183 *
 184 * @is_filtering:       Set to non-zero when filtering in progress
 185 * @parent:             pointer to struct dmx_demux
 186 * @priv:               pointer to private data of the API client
 187 * @check_crc:          If non-zero, check the CRC values of filtered sections.
 188 * @set:                sets the section filter
 189 * @allocate_filter:    This function is used to allocate a section filter on
 190 *                      the demux. It should only be called when no filtering
 191 *                      is in progress on this section feed. If a filter cannot
 192 *                      be allocated, the function fails with -ENOSPC.
 193 * @release_filter:     This function releases all the resources of a
 194 *                      previously allocated section filter. The function
 195 *                      should not be called while filtering is in progress
 196 *                      on this section feed. After calling this function,
 197 *                      the caller should not try to dereference the filter
 198 *                      pointer.
 199 * @start_filtering:    starts section filtering
 200 * @stop_filtering:     stops section filtering
 201 *
 202 * A TS feed is typically mapped to a hardware PID filter on the demux chip.
 203 * Using this API, the client can set the filtering properties to start/stop
 204 * filtering TS packets on a particular TS feed.
 205 */
 206struct dmx_section_feed {
 207        int is_filtering;
 208        struct dmx_demux *parent;
 209        void *priv;
 210
 211        int check_crc;
 212
 213        /* private: Used internally at dvb_demux.c */
 214        u32 crc_val;
 215
 216        u8 *secbuf;
 217        u8 secbuf_base[DMX_MAX_SECFEED_SIZE];
 218        u16 secbufp, seclen, tsfeedp;
 219
 220        /* public: */
 221        int (*set)(struct dmx_section_feed *feed,
 222                   u16 pid,
 223                   size_t circular_buffer_size,
 224                   int check_crc);
 225        int (*allocate_filter)(struct dmx_section_feed *feed,
 226                               struct dmx_section_filter **filter);
 227        int (*release_filter)(struct dmx_section_feed *feed,
 228                              struct dmx_section_filter *filter);
 229        int (*start_filtering)(struct dmx_section_feed *feed);
 230        int (*stop_filtering)(struct dmx_section_feed *feed);
 231};
 232
 233/**
 234 * DOC: Demux Callback
 235 *
 236 * This kernel-space API comprises the callback functions that deliver filtered
 237 * data to the demux client. Unlike the other DVB kABIs, these functions are
 238 * provided by the client and called from the demux code.
 239 *
 240 * The function pointers of this abstract interface are not packed into a
 241 * structure as in the other demux APIs, because the callback functions are
 242 * registered and used independent of each other. As an example, it is possible
 243 * for the API client to provide several callback functions for receiving TS
 244 * packets and no callbacks for PES packets or sections.
 245 *
 246 * The functions that implement the callback API need not be re-entrant: when
 247 * a demux driver calls one of these functions, the driver is not allowed to
 248 * call the function again before the original call returns. If a callback is
 249 * triggered by a hardware interrupt, it is recommended to use the Linux
 250 * bottom half mechanism or start a tasklet instead of making the callback
 251 * function call directly from a hardware interrupt.
 252 *
 253 * This mechanism is implemented by dmx_ts_cb() and dmx_section_cb()
 254 * callbacks.
 255 */
 256
 257/**
 258 * typedef dmx_ts_cb - DVB demux TS filter callback function prototype
 259 *
 260 * @buffer1:            Pointer to the start of the filtered TS packets.
 261 * @buffer1_length:     Length of the TS data in buffer1.
 262 * @buffer2:            Pointer to the tail of the filtered TS packets, or NULL.
 263 * @buffer2_length:     Length of the TS data in buffer2.
 264 * @source:             Indicates which TS feed is the source of the callback.
 265 *
 266 * This function callback prototype, provided by the client of the demux API,
 267 * is called from the demux code. The function is only called when filtering
 268 * on ae TS feed has been enabled using the start_filtering() function at
 269 * the &dmx_demux.
 270 * Any TS packets that match the filter settings are copied to a circular
 271 * buffer. The filtered TS packets are delivered to the client using this
 272 * callback function. The size of the circular buffer is controlled by the
 273 * circular_buffer_size parameter of the &dmx_ts_feed.@set function.
 274 * It is expected that the @buffer1 and @buffer2 callback parameters point to
 275 * addresses within the circular buffer, but other implementations are also
 276 * possible. Note that the called party should not try to free the memory
 277 * the @buffer1 and @buffer2 parameters point to.
 278 *
 279 * When this function is called, the @buffer1 parameter typically points to
 280 * the start of the first undelivered TS packet within a circular buffer.
 281 * The @buffer2 buffer parameter is normally NULL, except when the received
 282 * TS packets have crossed the last address of the circular buffer and
 283 * ”wrapped” to the beginning of the buffer. In the latter case the @buffer1
 284 * parameter would contain an address within the circular buffer, while the
 285 * @buffer2 parameter would contain the first address of the circular buffer.
 286 * The number of bytes delivered with this function (i.e. @buffer1_length +
 287 * @buffer2_length) is usually equal to the value of callback_length parameter
 288 * given in the set() function, with one exception: if a timeout occurs before
 289 * receiving callback_length bytes of TS data, any undelivered packets are
 290 * immediately delivered to the client by calling this function. The timeout
 291 * duration is controlled by the set() function in the TS Feed API.
 292 *
 293 * If a TS packet is received with errors that could not be fixed by the
 294 * TS-level forward error correction (FEC), the Transport_error_indicator
 295 * flag of the TS packet header should be set. The TS packet should not be
 296 * discarded, as the error can possibly be corrected by a higher layer
 297 * protocol. If the called party is slow in processing the callback, it
 298 * is possible that the circular buffer eventually fills up. If this happens,
 299 * the demux driver should discard any TS packets received while the buffer
 300 * is full and return -EOVERFLOW.
 301 *
 302 * The type of data returned to the callback can be selected by the
 303 * &dmx_ts_feed.@set function. The type parameter decides if the raw
 304 * TS packet (TS_PACKET) or just the payload (TS_PACKET|TS_PAYLOAD_ONLY)
 305 * should be returned. If additionally the TS_DECODER bit is set the stream
 306 * will also be sent to the hardware MPEG decoder.
 307 *
 308 * Return:
 309 *      0, on success;
 310 *      -EOVERFLOW, on buffer overflow.
 311 */
 312typedef int (*dmx_ts_cb)(const u8 *buffer1,
 313                         size_t buffer1_length,
 314                         const u8 *buffer2,
 315                         size_t buffer2_length,
 316                         struct dmx_ts_feed *source);
 317
 318/**
 319 * typedef dmx_section_cb - DVB demux TS filter callback function prototype
 320 *
 321 * @buffer1:            Pointer to the start of the filtered section, e.g.
 322 *                      within the circular buffer of the demux driver.
 323 * @buffer1_len:        Length of the filtered section data in @buffer1,
 324 *                      including headers and CRC.
 325 * @buffer2:            Pointer to the tail of the filtered section data,
 326 *                      or NULL. Useful to handle the wrapping of a
 327 *                      circular buffer.
 328 * @buffer2_len:        Length of the filtered section data in @buffer2,
 329 *                      including headers and CRC.
 330 * @source:             Indicates which section feed is the source of the
 331 *                      callback.
 332 *
 333 * This function callback prototype, provided by the client of the demux API,
 334 * is called from the demux code. The function is only called when
 335 * filtering of sections has been enabled using the function
 336 * &dmx_ts_feed.@start_filtering. When the demux driver has received a
 337 * complete section that matches at least one section filter, the client
 338 * is notified via this callback function. Normally this function is called
 339 * for each received section; however, it is also possible to deliver
 340 * multiple sections with one callback, for example when the system load
 341 * is high. If an error occurs while receiving a section, this
 342 * function should be called with the corresponding error type set in the
 343 * success field, whether or not there is data to deliver. The Section Feed
 344 * implementation should maintain a circular buffer for received sections.
 345 * However, this is not necessary if the Section Feed API is implemented as
 346 * a client of the TS Feed API, because the TS Feed implementation then
 347 * buffers the received data. The size of the circular buffer can be
 348 * configured using the &dmx_ts_feed.@set function in the Section Feed API.
 349 * If there is no room in the circular buffer when a new section is received,
 350 * the section must be discarded. If this happens, the value of the success
 351 * parameter should be DMX_OVERRUN_ERROR on the next callback.
 352 */
 353typedef int (*dmx_section_cb)(const u8 *buffer1,
 354                              size_t buffer1_len,
 355                              const u8 *buffer2,
 356                              size_t buffer2_len,
 357                              struct dmx_section_filter *source);
 358
 359/*--------------------------------------------------------------------------*/
 360/* DVB Front-End */
 361/*--------------------------------------------------------------------------*/
 362
 363/**
 364 * enum dmx_frontend_source - Used to identify the type of frontend
 365 *
 366 * @DMX_MEMORY_FE:      The source of the demux is memory. It means that
 367 *                      the MPEG-TS to be filtered comes from userspace,
 368 *                      via write() syscall.
 369 *
 370 * @DMX_FRONTEND_0:     The source of the demux is a frontend connected
 371 *                      to the demux.
 372 */
 373enum dmx_frontend_source {
 374        DMX_MEMORY_FE,
 375        DMX_FRONTEND_0,
 376};
 377
 378/**
 379 * struct dmx_frontend - Structure that lists the frontends associated with
 380 *                       a demux
 381 *
 382 * @connectivity_list:  List of front-ends that can be connected to a
 383 *                      particular demux;
 384 * @source:             Type of the frontend.
 385 *
 386 * FIXME: this structure should likely be replaced soon by some
 387 *      media-controller based logic.
 388 */
 389struct dmx_frontend {
 390        struct list_head connectivity_list;
 391        enum dmx_frontend_source source;
 392};
 393
 394/*
 395 * MPEG-2 TS Demux
 396 */
 397
 398/**
 399 * enum dmx_demux_caps - MPEG-2 TS Demux capabilities bitmap
 400 *
 401 * @DMX_TS_FILTERING:           set if TS filtering is supported;
 402 * @DMX_SECTION_FILTERING:      set if section filtering is supported;
 403 * @DMX_MEMORY_BASED_FILTERING: set if write() available.
 404 *
 405 * Those flags are OR'ed in the &dmx_demux.&capabilities field
 406 */
 407enum dmx_demux_caps {
 408        DMX_TS_FILTERING = 1,
 409        DMX_SECTION_FILTERING = 4,
 410        DMX_MEMORY_BASED_FILTERING = 8,
 411};
 412
 413/*
 414 * Demux resource type identifier.
 415*/
 416
 417/*
 418 * DMX_FE_ENTRY(): Casts elements in the list of registered
 419 * front-ends from the generic type struct list_head
 420 * to the type * struct dmx_frontend
 421 *.
 422*/
 423
 424#define DMX_FE_ENTRY(list) \
 425        list_entry(list, struct dmx_frontend, connectivity_list)
 426
 427/**
 428 * struct dmx_demux - Structure that contains the demux capabilities and
 429 *                    callbacks.
 430 *
 431 * @capabilities: Bitfield of capability flags.
 432 *
 433 * @frontend: Front-end connected to the demux
 434 *
 435 * @priv: Pointer to private data of the API client
 436 *
 437 * @open: This function reserves the demux for use by the caller and, if
 438 *      necessary, initializes the demux. When the demux is no longer needed,
 439 *      the function @close should be called. It should be possible for
 440 *      multiple clients to access the demux at the same time. Thus, the
 441 *      function implementation should increment the demux usage count when
 442 *      @open is called and decrement it when @close is called.
 443 *      The @demux function parameter contains a pointer to the demux API and
 444 *      instance data.
 445 *      It returns
 446 *              0 on success;
 447 *              -EUSERS, if maximum usage count was reached;
 448 *              -EINVAL, on bad parameter.
 449 *
 450 * @close: This function reserves the demux for use by the caller and, if
 451 *      necessary, initializes the demux. When the demux is no longer needed,
 452 *      the function @close should be called. It should be possible for
 453 *      multiple clients to access the demux at the same time. Thus, the
 454 *      function implementation should increment the demux usage count when
 455 *      @open is called and decrement it when @close is called.
 456 *      The @demux function parameter contains a pointer to the demux API and
 457 *      instance data.
 458 *      It returns
 459 *              0 on success;
 460 *              -ENODEV, if demux was not in use (e. g. no users);
 461 *              -EINVAL, on bad parameter.
 462 *
 463 * @write: This function provides the demux driver with a memory buffer
 464 *      containing TS packets. Instead of receiving TS packets from the DVB
 465 *      front-end, the demux driver software will read packets from memory.
 466 *      Any clients of this demux with active TS, PES or Section filters will
 467 *      receive filtered data via the Demux callback API (see 0). The function
 468 *      returns when all the data in the buffer has been consumed by the demux.
 469 *      Demux hardware typically cannot read TS from memory. If this is the
 470 *      case, memory-based filtering has to be implemented entirely in software.
 471 *      The @demux function parameter contains a pointer to the demux API and
 472 *      instance data.
 473 *      The @buf function parameter contains a pointer to the TS data in
 474 *      kernel-space memory.
 475 *      The @count function parameter contains the length of the TS data.
 476 *      It returns
 477 *              0 on success;
 478 *              -ERESTARTSYS, if mutex lock was interrupted;
 479 *              -EINTR, if a signal handling is pending;
 480 *              -ENODEV, if demux was removed;
 481 *              -EINVAL, on bad parameter.
 482 *
 483 * @allocate_ts_feed: Allocates a new TS feed, which is used to filter the TS
 484 *      packets carrying a certain PID. The TS feed normally corresponds to a
 485 *      hardware PID filter on the demux chip.
 486 *      The @demux function parameter contains a pointer to the demux API and
 487 *      instance data.
 488 *      The @feed function parameter contains a pointer to the TS feed API and
 489 *      instance data.
 490 *      The @callback function parameter contains a pointer to the callback
 491 *      function for passing received TS packet.
 492 *      It returns
 493 *              0 on success;
 494 *              -ERESTARTSYS, if mutex lock was interrupted;
 495 *              -EBUSY, if no more TS feeds is available;
 496 *              -EINVAL, on bad parameter.
 497 *
 498 * @release_ts_feed: Releases the resources allocated with @allocate_ts_feed.
 499 *      Any filtering in progress on the TS feed should be stopped before
 500 *      calling this function.
 501 *      The @demux function parameter contains a pointer to the demux API and
 502 *      instance data.
 503 *      The @feed function parameter contains a pointer to the TS feed API and
 504 *      instance data.
 505 *      It returns
 506 *              0 on success;
 507 *              -EINVAL on bad parameter.
 508 *
 509 * @allocate_section_feed: Allocates a new section feed, i.e. a demux resource
 510 *      for filtering and receiving sections. On platforms with hardware
 511 *      support for section filtering, a section feed is directly mapped to
 512 *      the demux HW. On other platforms, TS packets are first PID filtered in
 513 *      hardware and a hardware section filter then emulated in software. The
 514 *      caller obtains an API pointer of type dmx_section_feed_t as an out
 515 *      parameter. Using this API the caller can set filtering parameters and
 516 *      start receiving sections.
 517 *      The @demux function parameter contains a pointer to the demux API and
 518 *      instance data.
 519 *      The @feed function parameter contains a pointer to the TS feed API and
 520 *      instance data.
 521 *      The @callback function parameter contains a pointer to the callback
 522 *      function for passing received TS packet.
 523 *      It returns
 524 *              0 on success;
 525 *              -EBUSY, if no more TS feeds is available;
 526 *              -EINVAL, on bad parameter.
 527 *
 528 * @release_section_feed: Releases the resources allocated with
 529 *      @allocate_section_feed, including allocated filters. Any filtering in
 530 *      progress on the section feed should be stopped before calling this
 531 *      function.
 532 *      The @demux function parameter contains a pointer to the demux API and
 533 *      instance data.
 534 *      The @feed function parameter contains a pointer to the TS feed API and
 535 *      instance data.
 536 *      It returns
 537 *              0 on success;
 538 *              -EINVAL, on bad parameter.
 539 *
 540 * @add_frontend: Registers a connectivity between a demux and a front-end,
 541 *      i.e., indicates that the demux can be connected via a call to
 542 *      @connect_frontend to use the given front-end as a TS source. The
 543 *      client of this function has to allocate dynamic or static memory for
 544 *      the frontend structure and initialize its fields before calling this
 545 *      function. This function is normally called during the driver
 546 *      initialization. The caller must not free the memory of the frontend
 547 *      struct before successfully calling @remove_frontend.
 548 *      The @demux function parameter contains a pointer to the demux API and
 549 *      instance data.
 550 *      The @frontend function parameter contains a pointer to the front-end
 551 *      instance data.
 552 *      It returns
 553 *              0 on success;
 554 *              -EINVAL, on bad parameter.
 555 *
 556 * @remove_frontend: Indicates that the given front-end, registered by a call
 557 *      to @add_frontend, can no longer be connected as a TS source by this
 558 *      demux. The function should be called when a front-end driver or a demux
 559 *      driver is removed from the system. If the front-end is in use, the
 560 *      function fails with the return value of -EBUSY. After successfully
 561 *      calling this function, the caller can free the memory of the frontend
 562 *      struct if it was dynamically allocated before the @add_frontend
 563 *      operation.
 564 *      The @demux function parameter contains a pointer to the demux API and
 565 *      instance data.
 566 *      The @frontend function parameter contains a pointer to the front-end
 567 *      instance data.
 568 *      It returns
 569 *              0 on success;
 570 *              -ENODEV, if the front-end was not found,
 571 *              -EINVAL, on bad parameter.
 572 *
 573 * @get_frontends: Provides the APIs of the front-ends that have been
 574 *      registered for this demux. Any of the front-ends obtained with this
 575 *      call can be used as a parameter for @connect_frontend. The include
 576 *      file demux.h contains the macro DMX_FE_ENTRY() for converting an
 577 *      element of the generic type struct &list_head * to the type
 578 *      struct &dmx_frontend *. The caller must not free the memory of any of
 579 *      the elements obtained via this function call.
 580 *      The @demux function parameter contains a pointer to the demux API and
 581 *      instance data.
 582 *      It returns a struct list_head pointer to the list of front-end
 583 *      interfaces, or NULL in the case of an empty list.
 584 *
 585 * @connect_frontend: Connects the TS output of the front-end to the input of
 586 *      the demux. A demux can only be connected to a front-end registered to
 587 *      the demux with the function @add_frontend. It may or may not be
 588 *      possible to connect multiple demuxes to the same front-end, depending
 589 *      on the capabilities of the HW platform. When not used, the front-end
 590 *      should be released by calling @disconnect_frontend.
 591 *      The @demux function parameter contains a pointer to the demux API and
 592 *      instance data.
 593 *      The @frontend function parameter contains a pointer to the front-end
 594 *      instance data.
 595 *      It returns
 596 *              0 on success;
 597 *              -EINVAL, on bad parameter.
 598 *
 599 * @disconnect_frontend: Disconnects the demux and a front-end previously
 600 *      connected by a @connect_frontend call.
 601 *      The @demux function parameter contains a pointer to the demux API and
 602 *      instance data.
 603 *      It returns
 604 *              0 on success;
 605 *              -EINVAL on bad parameter.
 606 *
 607 * @get_pes_pids: Get the PIDs for DMX_PES_AUDIO0, DMX_PES_VIDEO0,
 608 *      DMX_PES_TELETEXT0, DMX_PES_SUBTITLE0 and DMX_PES_PCR0.
 609 *      The @demux function parameter contains a pointer to the demux API and
 610 *      instance data.
 611 *      The @pids function parameter contains an array with five u16 elements
 612 *      where the PIDs will be stored.
 613 *      It returns
 614 *              0 on success;
 615 *              -EINVAL on bad parameter.
 616 */
 617
 618struct dmx_demux {
 619        enum dmx_demux_caps capabilities;
 620        struct dmx_frontend *frontend;
 621        void *priv;
 622        int (*open)(struct dmx_demux *demux);
 623        int (*close)(struct dmx_demux *demux);
 624        int (*write)(struct dmx_demux *demux, const char __user *buf,
 625                     size_t count);
 626        int (*allocate_ts_feed)(struct dmx_demux *demux,
 627                                struct dmx_ts_feed **feed,
 628                                dmx_ts_cb callback);
 629        int (*release_ts_feed)(struct dmx_demux *demux,
 630                               struct dmx_ts_feed *feed);
 631        int (*allocate_section_feed)(struct dmx_demux *demux,
 632                                     struct dmx_section_feed **feed,
 633                                     dmx_section_cb callback);
 634        int (*release_section_feed)(struct dmx_demux *demux,
 635                                    struct dmx_section_feed *feed);
 636        int (*add_frontend)(struct dmx_demux *demux,
 637                            struct dmx_frontend *frontend);
 638        int (*remove_frontend)(struct dmx_demux *demux,
 639                               struct dmx_frontend *frontend);
 640        struct list_head *(*get_frontends)(struct dmx_demux *demux);
 641        int (*connect_frontend)(struct dmx_demux *demux,
 642                                struct dmx_frontend *frontend);
 643        int (*disconnect_frontend)(struct dmx_demux *demux);
 644
 645        int (*get_pes_pids)(struct dmx_demux *demux, u16 *pids);
 646
 647        /* private: Not used upstream and never documented */
 648#if 0
 649        int (*get_caps)(struct dmx_demux *demux, struct dmx_caps *caps);
 650        int (*set_source)(struct dmx_demux *demux, const dmx_source_t *src);
 651#endif
 652        /*
 653         * private: Only used at av7110, to read some data from firmware.
 654         *      As this was never documented, we have no clue about what's
 655         *      there, and its usage on other drivers aren't encouraged.
 656         */
 657        int (*get_stc)(struct dmx_demux *demux, unsigned int num,
 658                       u64 *stc, unsigned int *base);
 659};
 660
 661#endif /* #ifndef __DEMUX_H */
 662