1/******************************************************************************
2 * sndif.h
3 *
4 * Unified sound-device I/O interface for Xen guest OSes.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to
8 * deal in the Software without restriction, including without limitation the
9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
23 *
24 * Copyright (C) 2013-2015 GlobalLogic Inc.
25 * Copyright (C) 2016-2017 EPAM Systems Inc.
26 *
27 * Authors: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
28 *          Oleksandr Grytsov <oleksandr_grytsov@epam.com>
29 *          Oleksandr Dmytryshyn <oleksandr.dmytryshyn@globallogic.com>
30 *          Iurii Konovalenko <iurii.konovalenko@globallogic.com>
31 */
32
33#ifndef __XEN_PUBLIC_IO_SNDIF_H__
34#define __XEN_PUBLIC_IO_SNDIF_H__
35
36#include "ring.h"
37#include "../grant_table.h"
38
39/*
40 ******************************************************************************
41 *                           Protocol version
42 ******************************************************************************
43 */
44#define XENSND_PROTOCOL_VERSION         2
45
46/*
47 ******************************************************************************
48 *                  Feature and Parameter Negotiation
49 ******************************************************************************
50 *
51 * Front->back notifications: when enqueuing a new request, sending a
52 * notification can be made conditional on xensnd_req (i.e., the generic
53 * hold-off mechanism provided by the ring macros). Backends must set
54 * xensnd_req appropriately (e.g., using RING_FINAL_CHECK_FOR_REQUESTS()).
55 *
56 * Back->front notifications: when enqueuing a new response, sending a
57 * notification can be made conditional on xensnd_resp (i.e., the generic
58 * hold-off mechanism provided by the ring macros). Frontends must set
59 * xensnd_resp appropriately (e.g., using RING_FINAL_CHECK_FOR_RESPONSES()).
60 *
61 * The two halves of a para-virtual sound card driver utilize nodes within
62 * XenStore to communicate capabilities and to negotiate operating parameters.
63 * This section enumerates these nodes which reside in the respective front and
64 * backend portions of XenStore, following the XenBus convention.
65 *
66 * All data in XenStore is stored as strings. Nodes specifying numeric
67 * values are encoded in decimal. Integer value ranges listed below are
68 * expressed as fixed sized integer types capable of storing the conversion
69 * of a properly formated node string, without loss of information.
70 *
71 ******************************************************************************
72 *                        Example configuration
73 ******************************************************************************
74 *
75 * Note: depending on the use-case backend can expose more sound cards and
76 * PCM devices/streams than the underlying HW physically has by employing
77 * SW mixers, configuring virtual sound streams, channels etc.
78 *
79 * This is an example of backend and frontend configuration:
80 *
81 *--------------------------------- Backend -----------------------------------
82 *
83 * /local/domain/0/backend/vsnd/1/0/frontend-id = "1"
84 * /local/domain/0/backend/vsnd/1/0/frontend = "/local/domain/1/device/vsnd/0"
85 * /local/domain/0/backend/vsnd/1/0/state = "4"
86 * /local/domain/0/backend/vsnd/1/0/versions = "1,2"
87 *
88 *--------------------------------- Frontend ----------------------------------
89 *
90 * /local/domain/1/device/vsnd/0/backend-id = "0"
91 * /local/domain/1/device/vsnd/0/backend = "/local/domain/0/backend/vsnd/1/0"
92 * /local/domain/1/device/vsnd/0/state = "4"
93 * /local/domain/1/device/vsnd/0/version = "1"
94 *
95 *----------------------------- Card configuration ----------------------------
96 *
97 * /local/domain/1/device/vsnd/0/short-name = "Card short name"
98 * /local/domain/1/device/vsnd/0/long-name = "Card long name"
99 * /local/domain/1/device/vsnd/0/sample-rates = "8000,32000,44100,48000,96000"
100 * /local/domain/1/device/vsnd/0/sample-formats = "s8,u8,s16_le,s16_be"
101 * /local/domain/1/device/vsnd/0/buffer-size = "262144"
102 *
103 *------------------------------- PCM device 0 --------------------------------
104 *
105 * /local/domain/1/device/vsnd/0/0/name = "General analog"
106 * /local/domain/1/device/vsnd/0/0/channels-max = "5"
107 *
108 *----------------------------- Stream 0, playback ----------------------------
109 *
110 * /local/domain/1/device/vsnd/0/0/0/type = "p"
111 * /local/domain/1/device/vsnd/0/0/0/sample-formats = "s8,u8"
112 * /local/domain/1/device/vsnd/0/0/0/unique-id = "0"
113 *
114 * /local/domain/1/device/vsnd/0/0/0/ring-ref = "386"
115 * /local/domain/1/device/vsnd/0/0/0/event-channel = "15"
116 * /local/domain/1/device/vsnd/0/0/0/evt-ring-ref = "1386"
117 * /local/domain/1/device/vsnd/0/0/0/evt-event-channel = "215"
118 *
119 *------------------------------ Stream 1, capture ----------------------------
120 *
121 * /local/domain/1/device/vsnd/0/0/1/type = "c"
122 * /local/domain/1/device/vsnd/0/0/1/channels-max = "2"
123 * /local/domain/1/device/vsnd/0/0/1/unique-id = "1"
124 *
125 * /local/domain/1/device/vsnd/0/0/1/ring-ref = "384"
126 * /local/domain/1/device/vsnd/0/0/1/event-channel = "13"
127 * /local/domain/1/device/vsnd/0/0/1/evt-ring-ref = "1384"
128 * /local/domain/1/device/vsnd/0/0/1/evt-event-channel = "213"
129 *
130 *------------------------------- PCM device 1 --------------------------------
131 *
132 * /local/domain/1/device/vsnd/0/1/name = "HDMI-0"
133 * /local/domain/1/device/vsnd/0/1/sample-rates = "8000,32000,44100"
134 *
135 *------------------------------ Stream 0, capture ----------------------------
136 *
137 * /local/domain/1/device/vsnd/0/1/0/type = "c"
138 * /local/domain/1/device/vsnd/0/1/0/unique-id = "2"
139 *
140 * /local/domain/1/device/vsnd/0/1/0/ring-ref = "387"
141 * /local/domain/1/device/vsnd/0/1/0/event-channel = "151"
142 * /local/domain/1/device/vsnd/0/1/0/evt-ring-ref = "1387"
143 * /local/domain/1/device/vsnd/0/1/0/evt-event-channel = "351"
144 *
145 *------------------------------- PCM device 2 --------------------------------
146 *
147 * /local/domain/1/device/vsnd/0/2/name = "SPDIF"
148 *
149 *----------------------------- Stream 0, playback ----------------------------
150 *
151 * /local/domain/1/device/vsnd/0/2/0/type = "p"
152 * /local/domain/1/device/vsnd/0/2/0/unique-id = "3"
153 *
154 * /local/domain/1/device/vsnd/0/2/0/ring-ref = "389"
155 * /local/domain/1/device/vsnd/0/2/0/event-channel = "152"
156 * /local/domain/1/device/vsnd/0/2/0/evt-ring-ref = "1389"
157 * /local/domain/1/device/vsnd/0/2/0/evt-event-channel = "452"
158 *
159 ******************************************************************************
160 *                            Backend XenBus Nodes
161 ******************************************************************************
162 *
163 *----------------------------- Protocol version ------------------------------
164 *
165 * versions
166 *      Values:         <string>
167 *
168 *      List of XENSND_LIST_SEPARATOR separated protocol versions supported
169 *      by the backend. For example "1,2,3".
170 *
171 ******************************************************************************
172 *                            Frontend XenBus Nodes
173 ******************************************************************************
174 *
175 *-------------------------------- Addressing ---------------------------------
176 *
177 * dom-id
178 *      Values:         <uint16_t>
179 *
180 *      Domain identifier.
181 *
182 * dev-id
183 *      Values:         <uint16_t>
184 *
185 *      Device identifier.
186 *
187 * pcm-dev-idx
188 *      Values:         <uint8_t>
189 *
190 *      Zero based contigous index of the PCM device.
191 *
192 * stream-idx
193 *      Values:         <uint8_t>
194 *
195 *      Zero based contigous index of the stream of the PCM device.
196 *
197 * The following pattern is used for addressing:
198 *   /local/domain/<dom-id>/device/vsnd/<dev-id>/<pcm-dev-idx>/<stream-idx>/...
199 *
200 *----------------------------- Protocol version ------------------------------
201 *
202 * version
203 *      Values:         <string>
204 *
205 *      Protocol version, chosen among the ones supported by the backend.
206 *
207 *------------------------------- PCM settings --------------------------------
208 *
209 * Every virtualized sound frontend has a set of PCM devices and streams, each
210 * could be individually configured. Part of the PCM configuration can be
211 * defined at higher level of the hierarchy and be fully or partially re-used
212 * by the underlying layers. These configuration values are:
213 *  o number of channels (min/max)
214 *  o supported sample rates
215 *  o supported sample formats.
216 * E.g. one can define these values for the whole card, device or stream.
217 * Every underlying layer in turn can re-define some or all of them to better
218 * fit its needs. For example, card may define number of channels to be
219 * in [1; 8] range, and some particular stream may be limited to [1; 2] only.
220 * The rule is that the underlying layer must be a subset of the upper layer
221 * range.
222 *
223 * channels-min
224 *      Values:         <uint8_t>
225 *
226 *      The minimum amount of channels that is supported, [1; channels-max].
227 *      Optional, if not set or omitted a value of 1 is used.
228 *
229 * channels-max
230 *      Values:         <uint8_t>
231 *
232 *      The maximum amount of channels that is supported.
233 *      Must be at least <channels-min>.
234 *
235 * sample-rates
236 *      Values:         <list of uint32_t>
237 *
238 *      List of supported sample rates separated by XENSND_LIST_SEPARATOR.
239 *      Sample rates are expressed as a list of decimal values w/o any
240 *      ordering requirement.
241 *
242 * sample-formats
243 *      Values:         <list of XENSND_PCM_FORMAT_XXX_STR>
244 *
245 *      List of supported sample formats separated by XENSND_LIST_SEPARATOR.
246 *      Items must not exceed XENSND_SAMPLE_FORMAT_MAX_LEN length.
247 *
248 * buffer-size
249 *      Values:         <uint32_t>
250 *
251 *      The maximum size in octets of the buffer to allocate per stream.
252 *
253 *----------------------- Virtual sound card settings -------------------------
254 * short-name
255 *      Values:         <char[32]>
256 *
257 *      Short name of the virtual sound card. Optional.
258 *
259 * long-name
260 *      Values:         <char[80]>
261 *
262 *      Long name of the virtual sound card. Optional.
263 *
264 *----------------------------- Device settings -------------------------------
265 * name
266 *      Values:         <char[80]>
267 *
268 *      Name of the sound device within the virtual sound card. Optional.
269 *
270 *----------------------------- Stream settings -------------------------------
271 *
272 * type
273 *      Values:         "p", "c"
274 *
275 *      Stream type: "p" - playback stream, "c" - capture stream
276 *
277 *      If both capture and playback are needed then two streams need to be
278 *      defined under the same device.
279 *
280 * unique-id
281 *      Values:         <string>
282 *
283 *      After stream initialization it is assigned a unique ID, so every
284 *      stream of the frontend can be identified by the backend by this ID.
285 *      This can be UUID or such.
286 *
287 *-------------------- Stream Request Transport Parameters --------------------
288 *
289 * event-channel
290 *      Values:         <uint32_t>
291 *
292 *      The identifier of the Xen event channel used to signal activity
293 *      in the ring buffer.
294 *
295 * ring-ref
296 *      Values:         <uint32_t>
297 *
298 *      The Xen grant reference granting permission for the backend to map
299 *      a sole page in a single page sized ring buffer.
300 *
301 *--------------------- Stream Event Transport Parameters ---------------------
302 *
303 * This communication path is used to deliver asynchronous events from backend
304 * to frontend, set up per stream.
305 *
306 * evt-event-channel
307 *      Values:         <uint32_t>
308 *
309 *      The identifier of the Xen event channel used to signal activity
310 *      in the ring buffer.
311 *
312 * evt-ring-ref
313 *      Values:         <uint32_t>
314 *
315 *      The Xen grant reference granting permission for the backend to map
316 *      a sole page in a single page sized ring buffer.
317 *
318 ******************************************************************************
319 *                               STATE DIAGRAMS
320 ******************************************************************************
321 *
322 * Tool stack creates front and back state nodes with initial state
323 * XenbusStateInitialising.
324 * Tool stack creates and sets up frontend sound configuration nodes per domain.
325 *
326 * Front                                Back
327 * =================================    =====================================
328 * XenbusStateInitialising              XenbusStateInitialising
329 *                                       o Query backend device identification
330 *                                         data.
331 *                                       o Open and validate backend device.
332 *                                                      |
333 *                                                      |
334 *                                                      V
335 *                                      XenbusStateInitWait
336 *
337 * o Query frontend configuration
338 * o Allocate and initialize
339 *   event channels per configured
340 *   playback/capture stream.
341 * o Publish transport parameters
342 *   that will be in effect during
343 *   this connection.
344 *              |
345 *              |
346 *              V
347 * XenbusStateInitialised
348 *
349 *                                       o Query frontend transport parameters.
350 *                                       o Connect to the event channels.
351 *                                                      |
352 *                                                      |
353 *                                                      V
354 *                                      XenbusStateConnected
355 *
356 *  o Create and initialize OS
357 *    virtual sound device instances
358 *    as per configuration.
359 *              |
360 *              |
361 *              V
362 * XenbusStateConnected
363 *
364 *                                      XenbusStateUnknown
365 *                                      XenbusStateClosed
366 *                                      XenbusStateClosing
367 * o Remove virtual sound device
368 * o Remove event channels
369 *              |
370 *              |
371 *              V
372 * XenbusStateClosed
373 *
374 *------------------------------- Recovery flow -------------------------------
375 *
376 * In case of frontend unrecoverable errors backend handles that as
377 * if frontend goes into the XenbusStateClosed state.
378 *
379 * In case of backend unrecoverable errors frontend tries removing
380 * the virtualized device. If this is possible at the moment of error,
381 * then frontend goes into the XenbusStateInitialising state and is ready for
382 * new connection with backend. If the virtualized device is still in use and
383 * cannot be removed, then frontend goes into the XenbusStateReconfiguring state
384 * until either the virtualized device removed or backend initiates a new
385 * connection. On the virtualized device removal frontend goes into the
386 * XenbusStateInitialising state.
387 *
388 * Note on XenbusStateReconfiguring state of the frontend: if backend has
389 * unrecoverable errors then frontend cannot send requests to the backend
390 * and thus cannot provide functionality of the virtualized device anymore.
391 * After backend is back to normal the virtualized device may still hold some
392 * state: configuration in use, allocated buffers, client application state etc.
393 * So, in most cases, this will require frontend to implement complex recovery
394 * reconnect logic. Instead, by going into XenbusStateReconfiguring state,
395 * frontend will make sure no new clients of the virtualized device are
396 * accepted, allow existing client(s) to exit gracefully by signaling error
397 * state etc.
398 * Once all the clients are gone frontend can reinitialize the virtualized
399 * device and get into XenbusStateInitialising state again signaling the
400 * backend that a new connection can be made.
401 *
402 * There are multiple conditions possible under which frontend will go from
403 * XenbusStateReconfiguring into XenbusStateInitialising, some of them are OS
404 * specific. For example:
405 * 1. The underlying OS framework may provide callbacks to signal that the last
406 *    client of the virtualized device has gone and the device can be removed
407 * 2. Frontend can schedule a deferred work (timer/tasklet/workqueue)
408 *    to periodically check if this is the right time to re-try removal of
409 *    the virtualized device.
410 * 3. By any other means.
411 *
412 ******************************************************************************
413 *                             PCM FORMATS
414 ******************************************************************************
415 *
416 * XENSND_PCM_FORMAT_<format>[_<endian>]
417 *
418 * format: <S/U/F><bits> or <name>
419 *     S - signed, U - unsigned, F - float
420 *     bits - 8, 16, 24, 32
421 *     name - MU_LAW, GSM, etc.
422 *
423 * endian: <LE/BE>, may be absent
424 *     LE - Little endian, BE - Big endian
425 */
426#define XENSND_PCM_FORMAT_S8            0
427#define XENSND_PCM_FORMAT_U8            1
428#define XENSND_PCM_FORMAT_S16_LE        2
429#define XENSND_PCM_FORMAT_S16_BE        3
430#define XENSND_PCM_FORMAT_U16_LE        4
431#define XENSND_PCM_FORMAT_U16_BE        5
432#define XENSND_PCM_FORMAT_S24_LE        6
433#define XENSND_PCM_FORMAT_S24_BE        7
434#define XENSND_PCM_FORMAT_U24_LE        8
435#define XENSND_PCM_FORMAT_U24_BE        9
436#define XENSND_PCM_FORMAT_S32_LE        10
437#define XENSND_PCM_FORMAT_S32_BE        11
438#define XENSND_PCM_FORMAT_U32_LE        12
439#define XENSND_PCM_FORMAT_U32_BE        13
440#define XENSND_PCM_FORMAT_F32_LE        14 /* 4-byte float, IEEE-754 32-bit, */
441#define XENSND_PCM_FORMAT_F32_BE        15 /* range -1.0 to 1.0              */
442#define XENSND_PCM_FORMAT_F64_LE        16 /* 8-byte float, IEEE-754 64-bit, */
443#define XENSND_PCM_FORMAT_F64_BE        17 /* range -1.0 to 1.0              */
444#define XENSND_PCM_FORMAT_IEC958_SUBFRAME_LE 18
445#define XENSND_PCM_FORMAT_IEC958_SUBFRAME_BE 19
446#define XENSND_PCM_FORMAT_MU_LAW        20
447#define XENSND_PCM_FORMAT_A_LAW         21
448#define XENSND_PCM_FORMAT_IMA_ADPCM     22
449#define XENSND_PCM_FORMAT_MPEG          23
450#define XENSND_PCM_FORMAT_GSM           24
451
452/*
453 ******************************************************************************
454 *                             REQUEST CODES
455 ******************************************************************************
456 */
457#define XENSND_OP_OPEN                  0
458#define XENSND_OP_CLOSE                 1
459#define XENSND_OP_READ                  2
460#define XENSND_OP_WRITE                 3
461#define XENSND_OP_SET_VOLUME            4
462#define XENSND_OP_GET_VOLUME            5
463#define XENSND_OP_MUTE                  6
464#define XENSND_OP_UNMUTE                7
465#define XENSND_OP_TRIGGER               8
466#define XENSND_OP_HW_PARAM_QUERY        9
467
468#define XENSND_OP_TRIGGER_START         0
469#define XENSND_OP_TRIGGER_PAUSE         1
470#define XENSND_OP_TRIGGER_STOP          2
471#define XENSND_OP_TRIGGER_RESUME        3
472
473/*
474 ******************************************************************************
475 *                                 EVENT CODES
476 ******************************************************************************
477 */
478#define XENSND_EVT_CUR_POS              0
479
480/*
481 ******************************************************************************
482 *               XENSTORE FIELD AND PATH NAME STRINGS, HELPERS
483 ******************************************************************************
484 */
485#define XENSND_DRIVER_NAME              "vsnd"
486
487#define XENSND_LIST_SEPARATOR           ","
488/* Field names */
489#define XENSND_FIELD_BE_VERSIONS        "versions"
490#define XENSND_FIELD_FE_VERSION         "version"
491#define XENSND_FIELD_VCARD_SHORT_NAME   "short-name"
492#define XENSND_FIELD_VCARD_LONG_NAME    "long-name"
493#define XENSND_FIELD_RING_REF           "ring-ref"
494#define XENSND_FIELD_EVT_CHNL           "event-channel"
495#define XENSND_FIELD_EVT_RING_REF       "evt-ring-ref"
496#define XENSND_FIELD_EVT_EVT_CHNL       "evt-event-channel"
497#define XENSND_FIELD_DEVICE_NAME        "name"
498#define XENSND_FIELD_TYPE               "type"
499#define XENSND_FIELD_STREAM_UNIQUE_ID   "unique-id"
500#define XENSND_FIELD_CHANNELS_MIN       "channels-min"
501#define XENSND_FIELD_CHANNELS_MAX       "channels-max"
502#define XENSND_FIELD_SAMPLE_RATES       "sample-rates"
503#define XENSND_FIELD_SAMPLE_FORMATS     "sample-formats"
504#define XENSND_FIELD_BUFFER_SIZE        "buffer-size"
505
506/* Stream type field values. */
507#define XENSND_STREAM_TYPE_PLAYBACK     "p"
508#define XENSND_STREAM_TYPE_CAPTURE      "c"
509/* Sample rate max string length */
510#define XENSND_SAMPLE_RATE_MAX_LEN      11
511/* Sample format field values */
512#define XENSND_SAMPLE_FORMAT_MAX_LEN    24
513
514#define XENSND_PCM_FORMAT_S8_STR        "s8"
515#define XENSND_PCM_FORMAT_U8_STR        "u8"
516#define XENSND_PCM_FORMAT_S16_LE_STR    "s16_le"
517#define XENSND_PCM_FORMAT_S16_BE_STR    "s16_be"
518#define XENSND_PCM_FORMAT_U16_LE_STR    "u16_le"
519#define XENSND_PCM_FORMAT_U16_BE_STR    "u16_be"
520#define XENSND_PCM_FORMAT_S24_LE_STR    "s24_le"
521#define XENSND_PCM_FORMAT_S24_BE_STR    "s24_be"
522#define XENSND_PCM_FORMAT_U24_LE_STR    "u24_le"
523#define XENSND_PCM_FORMAT_U24_BE_STR    "u24_be"
524#define XENSND_PCM_FORMAT_S32_LE_STR    "s32_le"
525#define XENSND_PCM_FORMAT_S32_BE_STR    "s32_be"
526#define XENSND_PCM_FORMAT_U32_LE_STR    "u32_le"
527#define XENSND_PCM_FORMAT_U32_BE_STR    "u32_be"
528#define XENSND_PCM_FORMAT_F32_LE_STR    "float_le"
529#define XENSND_PCM_FORMAT_F32_BE_STR    "float_be"
530#define XENSND_PCM_FORMAT_F64_LE_STR    "float64_le"
531#define XENSND_PCM_FORMAT_F64_BE_STR    "float64_be"
532#define XENSND_PCM_FORMAT_IEC958_SUBFRAME_LE_STR "iec958_subframe_le"
533#define XENSND_PCM_FORMAT_IEC958_SUBFRAME_BE_STR "iec958_subframe_be"
534#define XENSND_PCM_FORMAT_MU_LAW_STR    "mu_law"
535#define XENSND_PCM_FORMAT_A_LAW_STR     "a_law"
536#define XENSND_PCM_FORMAT_IMA_ADPCM_STR "ima_adpcm"
537#define XENSND_PCM_FORMAT_MPEG_STR      "mpeg"
538#define XENSND_PCM_FORMAT_GSM_STR       "gsm"
539
540
541/*
542 ******************************************************************************
543 *                          STATUS RETURN CODES
544 ******************************************************************************
545 *
546 * Status return code is zero on success and -XEN_EXX on failure.
547 *
548 ******************************************************************************
549 *                              Assumptions
550 ******************************************************************************
551 * o usage of grant reference 0 as invalid grant reference:
552 *   grant reference 0 is valid, but never exposed to a PV driver,
553 *   because of the fact it is already in use/reserved by the PV console.
554 * o all references in this document to page sizes must be treated
555 *   as pages of size XEN_PAGE_SIZE unless otherwise noted.
556 *
557 ******************************************************************************
558 *       Description of the protocol between frontend and backend driver
559 ******************************************************************************
560 *
561 * The two halves of a Para-virtual sound driver communicate with
562 * each other using shared pages and event channels.
563 * Shared page contains a ring with request/response packets.
564 *
565 * Packets, used for input/output operations, e.g. read/write, set/get volume,
566 * etc., provide offset/length fields in order to allow asynchronous protocol
567 * operation with buffer space sharing: part of the buffer allocated at
568 * XENSND_OP_OPEN can be used for audio samples and part, for example,
569 * for volume control.
570 *
571 * All reserved fields in the structures below must be 0.
572 *
573 *---------------------------------- Requests ---------------------------------
574 *
575 * All request packets have the same length (64 octets)
576 * All request packets have common header:
577 *         0                1                 2               3        octet
578 * +----------------+----------------+----------------+----------------+
579 * |               id                |    operation   |    reserved    | 4
580 * +----------------+----------------+----------------+----------------+
581 * |                             reserved                              | 8
582 * +----------------+----------------+----------------+----------------+
583 *   id - uint16_t, private guest value, echoed in response
584 *   operation - uint8_t, operation code, XENSND_OP_???
585 *
586 * For all packets which use offset and length:
587 *   offset - uint32_t, read or write data offset within the shared buffer,
588 *     passed with XENSND_OP_OPEN request, octets,
589 *     [0; XENSND_OP_OPEN.buffer_sz - 1].
590 *   length - uint32_t, read or write data length, octets
591 *
592 * Request open - open a PCM stream for playback or capture:
593 *
594 *         0                1                 2               3        octet
595 * +----------------+----------------+----------------+----------------+
596 * |               id                | XENSND_OP_OPEN |    reserved    | 4
597 * +----------------+----------------+----------------+----------------+
598 * |                             reserved                              | 8
599 * +----------------+----------------+----------------+----------------+
600 * |                             pcm_rate                              | 12
601 * +----------------+----------------+----------------+----------------+
602 * |  pcm_format    |  pcm_channels  |             reserved            | 16
603 * +----------------+----------------+----------------+----------------+
604 * |                             buffer_sz                             | 20
605 * +----------------+----------------+----------------+----------------+
606 * |                           gref_directory                          | 24
607 * +----------------+----------------+----------------+----------------+
608 * |                             period_sz                             | 28
609 * +----------------+----------------+----------------+----------------+
610 * |                             reserved                              | 32
611 * +----------------+----------------+----------------+----------------+
612 * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
613 * +----------------+----------------+----------------+----------------+
614 * |                             reserved                              | 64
615 * +----------------+----------------+----------------+----------------+
616 *
617 * pcm_rate - uint32_t, stream data rate, Hz
618 * pcm_format - uint8_t, XENSND_PCM_FORMAT_XXX value
619 * pcm_channels - uint8_t, number of channels of this stream,
620 *   [channels-min; channels-max]
621 * buffer_sz - uint32_t, buffer size to be allocated, octets
622 * period_sz - uint32_t, event period size, octets
623 *   This is the requested value of the period at which frontend would
624 *   like to receive XENSND_EVT_CUR_POS notifications from the backend when
625 *   stream position advances during playback/capture.
626 *   It shows how many octets are expected to be played/captured before
627 *   sending such an event.
628 *   If set to 0 no XENSND_EVT_CUR_POS events are sent by the backend.
629 *
630 * gref_directory - grant_ref_t, a reference to the first shared page
631 *   describing shared buffer references. At least one page exists. If shared
632 *   buffer size  (buffer_sz) exceeds what can be addressed by this single page,
633 *   then reference to the next page must be supplied (see gref_dir_next_page
634 *   below)
635 */
636
637struct xensnd_open_req {
638    uint32_t pcm_rate;
639    uint8_t pcm_format;
640    uint8_t pcm_channels;
641    uint16_t reserved;
642    uint32_t buffer_sz;
643    grant_ref_t gref_directory;
644    uint32_t period_sz;
645};
646
647/*
648 * Shared page for XENSND_OP_OPEN buffer descriptor (gref_directory in the
649 *   request) employs a list of pages, describing all pages of the shared data
650 *   buffer:
651 *         0                1                 2               3        octet
652 * +----------------+----------------+----------------+----------------+
653 * |                        gref_dir_next_page                         | 4
654 * +----------------+----------------+----------------+----------------+
655 * |                              gref[0]                              | 8
656 * +----------------+----------------+----------------+----------------+
657 * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
658 * +----------------+----------------+----------------+----------------+
659 * |                              gref[i]                              | i*4+8
660 * +----------------+----------------+----------------+----------------+
661 * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
662 * +----------------+----------------+----------------+----------------+
663 * |                             gref[N - 1]                           | N*4+8
664 * +----------------+----------------+----------------+----------------+
665 *
666 * gref_dir_next_page - grant_ref_t, reference to the next page describing
667 *   page directory. Must be 0 if there are no more pages in the list.
668 * gref[i] - grant_ref_t, reference to a shared page of the buffer
669 *   allocated at XENSND_OP_OPEN
670 *
671 * Number of grant_ref_t entries in the whole page directory is not
672 * passed, but instead can be calculated as:
673 *   num_grefs_total = (XENSND_OP_OPEN.buffer_sz + XEN_PAGE_SIZE - 1) /
674 *       XEN_PAGE_SIZE
675 */
676
677struct xensnd_page_directory {
678    grant_ref_t gref_dir_next_page;
679    grant_ref_t gref[1]; /* Variable length */
680};
681
682/*
683 *  Request close - close an opened pcm stream:
684 *         0                1                 2               3        octet
685 * +----------------+----------------+----------------+----------------+
686 * |               id                | XENSND_OP_CLOSE|    reserved    | 4
687 * +----------------+----------------+----------------+----------------+
688 * |                             reserved                              | 8
689 * +----------------+----------------+----------------+----------------+
690 * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
691 * +----------------+----------------+----------------+----------------+
692 * |                             reserved                              | 64
693 * +----------------+----------------+----------------+----------------+
694 *
695 * Request read/write - used for read (for capture) or write (for playback):
696 *         0                1                 2               3        octet
697 * +----------------+----------------+----------------+----------------+
698 * |               id                |   operation    |    reserved    | 4
699 * +----------------+----------------+----------------+----------------+
700 * |                             reserved                              | 8
701 * +----------------+----------------+----------------+----------------+
702 * |                              offset                               | 12
703 * +----------------+----------------+----------------+----------------+
704 * |                              length                               | 16
705 * +----------------+----------------+----------------+----------------+
706 * |                             reserved                              | 20
707 * +----------------+----------------+----------------+----------------+
708 * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
709 * +----------------+----------------+----------------+----------------+
710 * |                             reserved                              | 64
711 * +----------------+----------------+----------------+----------------+
712 *
713 * operation - XENSND_OP_READ for read or XENSND_OP_WRITE for write
714 */
715
716struct xensnd_rw_req {
717    uint32_t offset;
718    uint32_t length;
719};
720
721/*
722 * Request set/get volume - set/get channels' volume of the stream given:
723 *         0                1                 2               3        octet
724 * +----------------+----------------+----------------+----------------+
725 * |               id                |   operation    |    reserved    | 4
726 * +----------------+----------------+----------------+----------------+
727 * |                             reserved                              | 8
728 * +----------------+----------------+----------------+----------------+
729 * |                              offset                               | 12
730 * +----------------+----------------+----------------+----------------+
731 * |                              length                               | 16
732 * +----------------+----------------+----------------+----------------+
733 * |                             reserved                              | 20
734 * +----------------+----------------+----------------+----------------+
735 * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
736 * +----------------+----------------+----------------+----------------+
737 * |                             reserved                              | 64
738 * +----------------+----------------+----------------+----------------+
739 *
740 * operation - XENSND_OP_SET_VOLUME for volume set
741 *   or XENSND_OP_GET_VOLUME for volume get
742 * Buffer passed with XENSND_OP_OPEN is used to exchange volume
743 * values:
744 *
745 *         0                1                 2               3        octet
746 * +----------------+----------------+----------------+----------------+
747 * |                             channel[0]                            | 4
748 * +----------------+----------------+----------------+----------------+
749 * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
750 * +----------------+----------------+----------------+----------------+
751 * |                             channel[i]                            | i*4
752 * +----------------+----------------+----------------+----------------+
753 * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
754 * +----------------+----------------+----------------+----------------+
755 * |                           channel[N - 1]                          | (N-1)*4
756 * +----------------+----------------+----------------+----------------+
757 *
758 * N = XENSND_OP_OPEN.pcm_channels
759 * i - uint8_t, index of a channel
760 * channel[i] - sint32_t, volume of i-th channel
761 * Volume is expressed as a signed value in steps of 0.001 dB,
762 * while 0 being 0 dB.
763 *
764 * Request mute/unmute - mute/unmute stream:
765 *         0                1                 2               3        octet
766 * +----------------+----------------+----------------+----------------+
767 * |               id                |   operation    |    reserved    | 4
768 * +----------------+----------------+----------------+----------------+
769 * |                             reserved                              | 8
770 * +----------------+----------------+----------------+----------------+
771 * |                              offset                               | 12
772 * +----------------+----------------+----------------+----------------+
773 * |                              length                               | 16
774 * +----------------+----------------+----------------+----------------+
775 * |                             reserved                              | 20
776 * +----------------+----------------+----------------+----------------+
777 * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
778 * +----------------+----------------+----------------+----------------+
779 * |                             reserved                              | 64
780 * +----------------+----------------+----------------+----------------+
781 *
782 * operation - XENSND_OP_MUTE for mute or XENSND_OP_UNMUTE for unmute
783 * Buffer passed with XENSND_OP_OPEN is used to exchange mute/unmute
784 * values:
785 *
786 *                                   0                                 octet
787 * +----------------+----------------+----------------+----------------+
788 * |                             channel[0]                            | 4
789 * +----------------+----------------+----------------+----------------+
790 * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
791 * +----------------+----------------+----------------+----------------+
792 * |                             channel[i]                            | i*4
793 * +----------------+----------------+----------------+----------------+
794 * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
795 * +----------------+----------------+----------------+----------------+
796 * |                           channel[N - 1]                          | (N-1)*4
797 * +----------------+----------------+----------------+----------------+
798 *
799 * N = XENSND_OP_OPEN.pcm_channels
800 * i - uint8_t, index of a channel
801 * channel[i] - uint8_t, non-zero if i-th channel needs to be muted/unmuted
802 *
803 *------------------------------------ N.B. -----------------------------------
804 *
805 * The 'struct xensnd_rw_req' is also used for XENSND_OP_SET_VOLUME,
806 * XENSND_OP_GET_VOLUME, XENSND_OP_MUTE, XENSND_OP_UNMUTE.
807 *
808 * Request stream running state change - trigger PCM stream running state
809 * to start, stop, pause or resume:
810 *
811 *         0                1                 2               3        octet
812 * +----------------+----------------+----------------+----------------+
813 * |               id                |   _OP_TRIGGER  |    reserved    | 4
814 * +----------------+----------------+----------------+----------------+
815 * |                             reserved                              | 8
816 * +----------------+----------------+----------------+----------------+
817 * |      type      |                     reserved                     | 12
818 * +----------------+----------------+----------------+----------------+
819 * |                             reserved                              | 16
820 * +----------------+----------------+----------------+----------------+
821 * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
822 * +----------------+----------------+----------------+----------------+
823 * |                             reserved                              | 64
824 * +----------------+----------------+----------------+----------------+
825 *
826 * type - uint8_t, XENSND_OP_TRIGGER_XXX value
827 */
828
829struct xensnd_trigger_req {
830    uint8_t type;
831};
832
833/*
834 * Request stream parameter ranges: request intervals and
835 *   masks of supported ranges for stream configuration values.
836 *
837 *   Sound device configuration for a particular stream is a limited subset
838 *   of the multidimensional configuration available on XenStore, e.g.
839 *   once the frame rate has been selected there is a limited supported range
840 *   for sample rates becomes available (which might be the same set configured
841 *   on XenStore or less). For example, selecting 96kHz sample rate may limit
842 *   number of channels available for such configuration from 4 to 2, etc.
843 *   Thus, each call to XENSND_OP_HW_PARAM_QUERY may reduce configuration
844 *   space making it possible to iteratively get the final stream configuration,
845 *   used in XENSND_OP_OPEN request.
846 *
847 *   See response format for this request.
848 *
849 *         0                1                 2               3        octet
850 * +----------------+----------------+----------------+----------------+
851 * |               id                | _HW_PARAM_QUERY|    reserved    | 4
852 * +----------------+----------------+----------------+----------------+
853 * |                             reserved                              | 8
854 * +----------------+----------------+----------------+----------------+
855 * |                     formats mask low 32-bit                       | 12
856 * +----------------+----------------+----------------+----------------+
857 * |                     formats mask high 32-bit                      | 16
858 * +----------------+----------------+----------------+----------------+
859 * |                              min rate                             | 20
860 * +----------------+----------------+----------------+----------------+
861 * |                              max rate                             | 24
862 * +----------------+----------------+----------------+----------------+
863 * |                            min channels                           | 28
864 * +----------------+----------------+----------------+----------------+
865 * |                            max channels                           | 32
866 * +----------------+----------------+----------------+----------------+
867 * |                         min buffer frames                         | 36
868 * +----------------+----------------+----------------+----------------+
869 * |                         max buffer frames                         | 40
870 * +----------------+----------------+----------------+----------------+
871 * |                         min period frames                         | 44
872 * +----------------+----------------+----------------+----------------+
873 * |                         max period frames                         | 48
874 * +----------------+----------------+----------------+----------------+
875 * |                             reserved                              | 52
876 * +----------------+----------------+----------------+----------------+
877 * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
878 * +----------------+----------------+----------------+----------------+
879 * |                             reserved                              | 64
880 * +----------------+----------------+----------------+----------------+
881 *
882 * formats - uint64_t, bit mask representing values of the parameter
883 *   made as bitwise OR of (1 << XENSND_PCM_FORMAT_XXX) values
884 *
885 * For interval parameters:
886 *   min - uint32_t, minimum value of the parameter
887 *   max - uint32_t, maximum value of the parameter
888 *
889 * Frame is defined as a product of the number of channels by the
890 * number of octets per one sample.
891 */
892
893struct xensnd_query_hw_param {
894    uint64_t formats;
895    struct {
896        uint32_t min;
897        uint32_t max;
898    } rates;
899    struct {
900        uint32_t min;
901        uint32_t max;
902    } channels;
903    struct {
904        uint32_t min;
905        uint32_t max;
906    } buffer;
907    struct {
908        uint32_t min;
909        uint32_t max;
910    } period;
911};
912
913/*
914 *---------------------------------- Responses --------------------------------
915 *
916 * All response packets have the same length (64 octets)
917 *
918 * All response packets have common header:
919 *         0                1                 2               3        octet
920 * +----------------+----------------+----------------+----------------+
921 * |               id                |    operation   |    reserved    | 4
922 * +----------------+----------------+----------------+----------------+
923 * |                              status                               | 8
924 * +----------------+----------------+----------------+----------------+
925 *
926 * id - uint16_t, copied from the request
927 * operation - uint8_t, XENSND_OP_* - copied from request
928 * status - int32_t, response status, zero on success and -XEN_EXX on failure
929 *
930 *
931 * HW parameter query response - response for XENSND_OP_HW_PARAM_QUERY:
932 *         0                1                 2               3        octet
933 * +----------------+----------------+----------------+----------------+
934 * |               id                |    operation   |    reserved    | 4
935 * +----------------+----------------+----------------+----------------+
936 * |                              status                               | 8
937 * +----------------+----------------+----------------+----------------+
938 * |                     formats mask low 32-bit                       | 12
939 * +----------------+----------------+----------------+----------------+
940 * |                     formats mask high 32-bit                      | 16
941 * +----------------+----------------+----------------+----------------+
942 * |                              min rate                             | 20
943 * +----------------+----------------+----------------+----------------+
944 * |                              max rate                             | 24
945 * +----------------+----------------+----------------+----------------+
946 * |                            min channels                           | 28
947 * +----------------+----------------+----------------+----------------+
948 * |                            max channels                           | 32
949 * +----------------+----------------+----------------+----------------+
950 * |                         min buffer frames                         | 36
951 * +----------------+----------------+----------------+----------------+
952 * |                         max buffer frames                         | 40
953 * +----------------+----------------+----------------+----------------+
954 * |                         min period frames                         | 44
955 * +----------------+----------------+----------------+----------------+
956 * |                         max period frames                         | 48
957 * +----------------+----------------+----------------+----------------+
958 * |                             reserved                              | 52
959 * +----------------+----------------+----------------+----------------+
960 * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
961 * +----------------+----------------+----------------+----------------+
962 * |                             reserved                              | 64
963 * +----------------+----------------+----------------+----------------+
964 *
965 * Meaning of the values in this response is the same as for
966 * XENSND_OP_HW_PARAM_QUERY request.
967 */
968
969/*
970 *----------------------------------- Events ----------------------------------
971 *
972 * Events are sent via shared page allocated by the front and propagated by
973 *   evt-event-channel/evt-ring-ref XenStore entries
974 * All event packets have the same length (64 octets)
975 * All event packets have common header:
976 *         0                1                 2               3        octet
977 * +----------------+----------------+----------------+----------------+
978 * |               id                |      type      |   reserved     | 4
979 * +----------------+----------------+----------------+----------------+
980 * |                             reserved                              | 8
981 * +----------------+----------------+----------------+----------------+
982 *
983 * id - uint16_t, event id, may be used by front
984 * type - uint8_t, type of the event
985 *
986 *
987 * Current stream position - event from back to front when stream's
988 *   playback/capture position has advanced:
989 *         0                1                 2               3        octet
990 * +----------------+----------------+----------------+----------------+
991 * |               id                |   _EVT_CUR_POS |   reserved     | 4
992 * +----------------+----------------+----------------+----------------+
993 * |                             reserved                              | 8
994 * +----------------+----------------+----------------+----------------+
995 * |                         position low 32-bit                       | 12
996 * +----------------+----------------+----------------+----------------+
997 * |                         position high 32-bit                      | 16
998 * +----------------+----------------+----------------+----------------+
999 * |                             reserved                              | 20
1000 * +----------------+----------------+----------------+----------------+
1001 * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
1002 * +----------------+----------------+----------------+----------------+
1003 * |                             reserved                              | 64
1004 * +----------------+----------------+----------------+----------------+
1005 *
1006 * position - current value of stream's playback/capture position, octets
1007 *
1008 */
1009
1010struct xensnd_cur_pos_evt {
1011    uint64_t position;
1012};
1013
1014struct xensnd_req {
1015    uint16_t id;
1016    uint8_t operation;
1017    uint8_t reserved[5];
1018    union {
1019        struct xensnd_open_req open;
1020        struct xensnd_rw_req rw;
1021        struct xensnd_trigger_req trigger;
1022        struct xensnd_query_hw_param hw_param;
1023        uint8_t reserved[56];
1024    } op;
1025};
1026
1027struct xensnd_resp {
1028    uint16_t id;
1029    uint8_t operation;
1030    uint8_t reserved;
1031    int32_t status;
1032    union {
1033        struct xensnd_query_hw_param hw_param;
1034        uint8_t reserved1[56];
1035    } resp;
1036};
1037
1038struct xensnd_evt {
1039    uint16_t id;
1040    uint8_t type;
1041    uint8_t reserved[5];
1042    union {
1043        struct xensnd_cur_pos_evt cur_pos;
1044        uint8_t reserved[56];
1045    } op;
1046};
1047
1048DEFINE_RING_TYPES(xen_sndif, struct xensnd_req, struct xensnd_resp);
1049
1050/*
1051 ******************************************************************************
1052 *                        Back to front events delivery
1053 ******************************************************************************
1054 * In order to deliver asynchronous events from back to front a shared page is
1055 * allocated by front and its granted reference propagated to back via
1056 * XenStore entries (evt-ring-ref/evt-event-channel).
1057 * This page has a common header used by both front and back to synchronize
1058 * access and control event's ring buffer, while back being a producer of the
1059 * events and front being a consumer. The rest of the page after the header
1060 * is used for event packets.
1061 *
1062 * Upon reception of an event(s) front may confirm its reception
1063 * for either each event, group of events or none.
1064 */
1065
1066struct xensnd_event_page {
1067    uint32_t in_cons;
1068    uint32_t in_prod;
1069    uint8_t reserved[56];
1070};
1071
1072#define XENSND_EVENT_PAGE_SIZE 4096
1073#define XENSND_IN_RING_OFFS (sizeof(struct xensnd_event_page))
1074#define XENSND_IN_RING_SIZE (XENSND_EVENT_PAGE_SIZE - XENSND_IN_RING_OFFS)
1075#define XENSND_IN_RING_LEN (XENSND_IN_RING_SIZE / sizeof(struct xensnd_evt))
1076#define XENSND_IN_RING(page) \
1077    ((struct xensnd_evt *)((char *)(page) + XENSND_IN_RING_OFFS))
1078#define XENSND_IN_RING_REF(page, idx) \
1079    (XENSND_IN_RING((page))[(idx) % XENSND_IN_RING_LEN])
1080
1081#endif /* __XEN_PUBLIC_IO_SNDIF_H__ */
1082
1083/*
1084 * Local variables:
1085 * mode: C
1086 * c-file-style: "BSD"
1087 * c-basic-offset: 4
1088 * tab-width: 4
1089 * indent-tabs-mode: nil
1090 * End:
1091 */
1092