1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * u_audio.c -- interface to USB gadget "ALSA sound card" utilities 4 * 5 * Copyright (C) 2016 6 * Author: Ruslan Bilovol <ruslan.bilovol@gmail.com> 7 * 8 * Sound card implementation was cut-and-pasted with changes 9 * from f_uac2.c and has: 10 * Copyright (C) 2011 11 * Yadwinder Singh (yadi.brar01@gmail.com) 12 * Jaswinder Singh (jaswinder.singh@linaro.org) 13 */ 14 15 #include <linux/module.h> 16 #include <sound/core.h> 17 #include <sound/pcm.h> 18 #include <sound/pcm_params.h> 19 20 #include "u_audio.h" 21 22 #define BUFF_SIZE_MAX (PAGE_SIZE * 16) 23 #define PRD_SIZE_MAX PAGE_SIZE 24 #define MIN_PERIODS 4 25 26 struct uac_req { 27 struct uac_rtd_params *pp; /* parent param */ 28 struct usb_request *req; 29 }; 30 31 /* Runtime data params for one stream */ 32 struct uac_rtd_params { 33 struct snd_uac_chip *uac; /* parent chip */ 34 bool ep_enabled; /* if the ep is enabled */ 35 36 struct snd_pcm_substream *ss; 37 38 /* Ring buffer */ 39 ssize_t hw_ptr; 40 41 void *rbuf; 42 43 unsigned max_psize; /* MaxPacketSize of endpoint */ 44 struct uac_req *ureq; 45 46 spinlock_t lock; 47 }; 48 49 struct snd_uac_chip { 50 struct g_audio *audio_dev; 51 52 struct uac_rtd_params p_prm; 53 struct uac_rtd_params c_prm; 54 55 struct snd_card *card; 56 struct snd_pcm *pcm; 57 58 /* timekeeping for the playback endpoint */ 59 unsigned int p_interval; 60 unsigned int p_residue; 61 62 /* pre-calculated values for playback iso completion */ 63 unsigned int p_pktsize; 64 unsigned int p_pktsize_residue; 65 unsigned int p_framesize; 66 }; 67 68 static const struct snd_pcm_hardware uac_pcm_hardware = { 69 .info = SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER 70 | SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID 71 | SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME, 72 .rates = SNDRV_PCM_RATE_CONTINUOUS, 73 .periods_max = BUFF_SIZE_MAX / PRD_SIZE_MAX, 74 .buffer_bytes_max = BUFF_SIZE_MAX, 75 .period_bytes_max = PRD_SIZE_MAX, 76 .periods_min = MIN_PERIODS, 77 }; 78 79 static void u_audio_iso_complete(struct usb_ep *ep, struct usb_request *req) 80 { 81 unsigned pending; 82 unsigned long flags, flags2; 83 unsigned int hw_ptr; 84 int status = req->status; 85 struct uac_req *ur = req->context; 86 struct snd_pcm_substream *substream; 87 struct snd_pcm_runtime *runtime; 88 struct uac_rtd_params *prm = ur->pp; 89 struct snd_uac_chip *uac = prm->uac; 90 91 /* i/f shutting down */ 92 if (!prm->ep_enabled || req->status == -ESHUTDOWN) 93 return; 94 95 /* 96 * We can't really do much about bad xfers. 97 * Afterall, the ISOCH xfers could fail legitimately. 98 */ 99 if (status) 100 pr_debug("%s: iso_complete status(%d) %d/%d\n", 101 __func__, status, req->actual, req->length); 102 103 substream = prm->ss; 104 105 /* Do nothing if ALSA isn't active */ 106 if (!substream) 107 goto exit; 108 109 snd_pcm_stream_lock_irqsave(substream, flags2); 110 111 runtime = substream->runtime; 112 if (!runtime || !snd_pcm_running(substream)) { 113 snd_pcm_stream_unlock_irqrestore(substream, flags2); 114 goto exit; 115 } 116 117 spin_lock_irqsave(&prm->lock, flags); 118 119 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) { 120 /* 121 * For each IN packet, take the quotient of the current data 122 * rate and the endpoint's interval as the base packet size. 123 * If there is a residue from this division, add it to the 124 * residue accumulator. 125 */ 126 req->length = uac->p_pktsize; 127 uac->p_residue += uac->p_pktsize_residue; 128 129 /* 130 * Whenever there are more bytes in the accumulator than we 131 * need to add one more sample frame, increase this packet's 132 * size and decrease the accumulator. 133 */ 134 if (uac->p_residue / uac->p_interval >= uac->p_framesize) { 135 req->length += uac->p_framesize; 136 uac->p_residue -= uac->p_framesize * 137 uac->p_interval; 138 } 139 140 req->actual = req->length; 141 } 142 143 hw_ptr = prm->hw_ptr; 144 145 spin_unlock_irqrestore(&prm->lock, flags); 146 147 /* Pack USB load in ALSA ring buffer */ 148 pending = runtime->dma_bytes - hw_ptr; 149 150 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) { 151 if (unlikely(pending < req->actual)) { 152 memcpy(req->buf, runtime->dma_area + hw_ptr, pending); 153 memcpy(req->buf + pending, runtime->dma_area, 154 req->actual - pending); 155 } else { 156 memcpy(req->buf, runtime->dma_area + hw_ptr, 157 req->actual); 158 } 159 } else { 160 if (unlikely(pending < req->actual)) { 161 memcpy(runtime->dma_area + hw_ptr, req->buf, pending); 162 memcpy(runtime->dma_area, req->buf + pending, 163 req->actual - pending); 164 } else { 165 memcpy(runtime->dma_area + hw_ptr, req->buf, 166 req->actual); 167 } 168 } 169 170 spin_lock_irqsave(&prm->lock, flags); 171 /* update hw_ptr after data is copied to memory */ 172 prm->hw_ptr = (hw_ptr + req->actual) % runtime->dma_bytes; 173 hw_ptr = prm->hw_ptr; 174 spin_unlock_irqrestore(&prm->lock, flags); 175 snd_pcm_stream_unlock_irqrestore(substream, flags2); 176 177 if ((hw_ptr % snd_pcm_lib_period_bytes(substream)) < req->actual) 178 snd_pcm_period_elapsed(substream); 179 180 exit: 181 if (usb_ep_queue(ep, req, GFP_ATOMIC)) 182 dev_err(uac->card->dev, "%d Error!\n", __LINE__); 183 } 184 185 static int uac_pcm_trigger(struct snd_pcm_substream *substream, int cmd) 186 { 187 struct snd_uac_chip *uac = snd_pcm_substream_chip(substream); 188 struct uac_rtd_params *prm; 189 struct g_audio *audio_dev; 190 struct uac_params *params; 191 unsigned long flags; 192 int err = 0; 193 194 audio_dev = uac->audio_dev; 195 params = &audio_dev->params; 196 197 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 198 prm = &uac->p_prm; 199 else 200 prm = &uac->c_prm; 201 202 spin_lock_irqsave(&prm->lock, flags); 203 204 /* Reset */ 205 prm->hw_ptr = 0; 206 207 switch (cmd) { 208 case SNDRV_PCM_TRIGGER_START: 209 case SNDRV_PCM_TRIGGER_RESUME: 210 prm->ss = substream; 211 break; 212 case SNDRV_PCM_TRIGGER_STOP: 213 case SNDRV_PCM_TRIGGER_SUSPEND: 214 prm->ss = NULL; 215 break; 216 default: 217 err = -EINVAL; 218 } 219 220 spin_unlock_irqrestore(&prm->lock, flags); 221 222 /* Clear buffer after Play stops */ 223 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK && !prm->ss) 224 memset(prm->rbuf, 0, prm->max_psize * params->req_number); 225 226 return err; 227 } 228 229 static snd_pcm_uframes_t uac_pcm_pointer(struct snd_pcm_substream *substream) 230 { 231 struct snd_uac_chip *uac = snd_pcm_substream_chip(substream); 232 struct uac_rtd_params *prm; 233 234 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) 235 prm = &uac->p_prm; 236 else 237 prm = &uac->c_prm; 238 239 return bytes_to_frames(substream->runtime, prm->hw_ptr); 240 } 241 242 static int uac_pcm_hw_params(struct snd_pcm_substream *substream, 243 struct snd_pcm_hw_params *hw_params) 244 { 245 return snd_pcm_lib_malloc_pages(substream, 246 params_buffer_bytes(hw_params)); 247 } 248 249 static int uac_pcm_hw_free(struct snd_pcm_substream *substream) 250 { 251 return snd_pcm_lib_free_pages(substream); 252 } 253 254 static int uac_pcm_open(struct snd_pcm_substream *substream) 255 { 256 struct snd_uac_chip *uac = snd_pcm_substream_chip(substream); 257 struct snd_pcm_runtime *runtime = substream->runtime; 258 struct g_audio *audio_dev; 259 struct uac_params *params; 260 int p_ssize, c_ssize; 261 int p_srate, c_srate; 262 int p_chmask, c_chmask; 263 264 audio_dev = uac->audio_dev; 265 params = &audio_dev->params; 266 p_ssize = params->p_ssize; 267 c_ssize = params->c_ssize; 268 p_srate = params->p_srate; 269 c_srate = params->c_srate; 270 p_chmask = params->p_chmask; 271 c_chmask = params->c_chmask; 272 uac->p_residue = 0; 273 274 runtime->hw = uac_pcm_hardware; 275 276 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) { 277 spin_lock_init(&uac->p_prm.lock); 278 runtime->hw.rate_min = p_srate; 279 switch (p_ssize) { 280 case 3: 281 runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE; 282 break; 283 case 4: 284 runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE; 285 break; 286 default: 287 runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE; 288 break; 289 } 290 runtime->hw.channels_min = num_channels(p_chmask); 291 runtime->hw.period_bytes_min = 2 * uac->p_prm.max_psize 292 / runtime->hw.periods_min; 293 } else { 294 spin_lock_init(&uac->c_prm.lock); 295 runtime->hw.rate_min = c_srate; 296 switch (c_ssize) { 297 case 3: 298 runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE; 299 break; 300 case 4: 301 runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE; 302 break; 303 default: 304 runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE; 305 break; 306 } 307 runtime->hw.channels_min = num_channels(c_chmask); 308 runtime->hw.period_bytes_min = 2 * uac->c_prm.max_psize 309 / runtime->hw.periods_min; 310 } 311 312 runtime->hw.rate_max = runtime->hw.rate_min; 313 runtime->hw.channels_max = runtime->hw.channels_min; 314 315 snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); 316 317 return 0; 318 } 319 320 /* ALSA cries without these function pointers */ 321 static int uac_pcm_null(struct snd_pcm_substream *substream) 322 { 323 return 0; 324 } 325 326 static const struct snd_pcm_ops uac_pcm_ops = { 327 .open = uac_pcm_open, 328 .close = uac_pcm_null, 329 .ioctl = snd_pcm_lib_ioctl, 330 .hw_params = uac_pcm_hw_params, 331 .hw_free = uac_pcm_hw_free, 332 .trigger = uac_pcm_trigger, 333 .pointer = uac_pcm_pointer, 334 .prepare = uac_pcm_null, 335 }; 336 337 static inline void free_ep(struct uac_rtd_params *prm, struct usb_ep *ep) 338 { 339 struct snd_uac_chip *uac = prm->uac; 340 struct g_audio *audio_dev; 341 struct uac_params *params; 342 int i; 343 344 if (!prm->ep_enabled) 345 return; 346 347 prm->ep_enabled = false; 348 349 audio_dev = uac->audio_dev; 350 params = &audio_dev->params; 351 352 for (i = 0; i < params->req_number; i++) { 353 if (prm->ureq[i].req) { 354 usb_ep_dequeue(ep, prm->ureq[i].req); 355 usb_ep_free_request(ep, prm->ureq[i].req); 356 prm->ureq[i].req = NULL; 357 } 358 } 359 360 if (usb_ep_disable(ep)) 361 dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__); 362 } 363 364 365 int u_audio_start_capture(struct g_audio *audio_dev) 366 { 367 struct snd_uac_chip *uac = audio_dev->uac; 368 struct usb_gadget *gadget = audio_dev->gadget; 369 struct device *dev = &gadget->dev; 370 struct usb_request *req; 371 struct usb_ep *ep; 372 struct uac_rtd_params *prm; 373 struct uac_params *params = &audio_dev->params; 374 int req_len, i; 375 376 ep = audio_dev->out_ep; 377 prm = &uac->c_prm; 378 config_ep_by_speed(gadget, &audio_dev->func, ep); 379 req_len = prm->max_psize; 380 381 prm->ep_enabled = true; 382 usb_ep_enable(ep); 383 384 for (i = 0; i < params->req_number; i++) { 385 if (!prm->ureq[i].req) { 386 req = usb_ep_alloc_request(ep, GFP_ATOMIC); 387 if (req == NULL) 388 return -ENOMEM; 389 390 prm->ureq[i].req = req; 391 prm->ureq[i].pp = prm; 392 393 req->zero = 0; 394 req->context = &prm->ureq[i]; 395 req->length = req_len; 396 req->complete = u_audio_iso_complete; 397 req->buf = prm->rbuf + i * prm->max_psize; 398 } 399 400 if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC)) 401 dev_err(dev, "%s:%d Error!\n", __func__, __LINE__); 402 } 403 404 return 0; 405 } 406 EXPORT_SYMBOL_GPL(u_audio_start_capture); 407 408 void u_audio_stop_capture(struct g_audio *audio_dev) 409 { 410 struct snd_uac_chip *uac = audio_dev->uac; 411 412 free_ep(&uac->c_prm, audio_dev->out_ep); 413 } 414 EXPORT_SYMBOL_GPL(u_audio_stop_capture); 415 416 int u_audio_start_playback(struct g_audio *audio_dev) 417 { 418 struct snd_uac_chip *uac = audio_dev->uac; 419 struct usb_gadget *gadget = audio_dev->gadget; 420 struct device *dev = &gadget->dev; 421 struct usb_request *req; 422 struct usb_ep *ep; 423 struct uac_rtd_params *prm; 424 struct uac_params *params = &audio_dev->params; 425 unsigned int factor, rate; 426 const struct usb_endpoint_descriptor *ep_desc; 427 int req_len, i; 428 429 ep = audio_dev->in_ep; 430 prm = &uac->p_prm; 431 config_ep_by_speed(gadget, &audio_dev->func, ep); 432 433 ep_desc = ep->desc; 434 435 /* pre-calculate the playback endpoint's interval */ 436 if (gadget->speed == USB_SPEED_FULL) 437 factor = 1000; 438 else 439 factor = 8000; 440 441 /* pre-compute some values for iso_complete() */ 442 uac->p_framesize = params->p_ssize * 443 num_channels(params->p_chmask); 444 rate = params->p_srate * uac->p_framesize; 445 uac->p_interval = factor / (1 << (ep_desc->bInterval - 1)); 446 uac->p_pktsize = min_t(unsigned int, rate / uac->p_interval, 447 prm->max_psize); 448 449 if (uac->p_pktsize < prm->max_psize) 450 uac->p_pktsize_residue = rate % uac->p_interval; 451 else 452 uac->p_pktsize_residue = 0; 453 454 req_len = uac->p_pktsize; 455 uac->p_residue = 0; 456 457 prm->ep_enabled = true; 458 usb_ep_enable(ep); 459 460 for (i = 0; i < params->req_number; i++) { 461 if (!prm->ureq[i].req) { 462 req = usb_ep_alloc_request(ep, GFP_ATOMIC); 463 if (req == NULL) 464 return -ENOMEM; 465 466 prm->ureq[i].req = req; 467 prm->ureq[i].pp = prm; 468 469 req->zero = 0; 470 req->context = &prm->ureq[i]; 471 req->length = req_len; 472 req->complete = u_audio_iso_complete; 473 req->buf = prm->rbuf + i * prm->max_psize; 474 } 475 476 if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC)) 477 dev_err(dev, "%s:%d Error!\n", __func__, __LINE__); 478 } 479 480 return 0; 481 } 482 EXPORT_SYMBOL_GPL(u_audio_start_playback); 483 484 void u_audio_stop_playback(struct g_audio *audio_dev) 485 { 486 struct snd_uac_chip *uac = audio_dev->uac; 487 488 free_ep(&uac->p_prm, audio_dev->in_ep); 489 } 490 EXPORT_SYMBOL_GPL(u_audio_stop_playback); 491 492 int g_audio_setup(struct g_audio *g_audio, const char *pcm_name, 493 const char *card_name) 494 { 495 struct snd_uac_chip *uac; 496 struct snd_card *card; 497 struct snd_pcm *pcm; 498 struct uac_params *params; 499 int p_chmask, c_chmask; 500 int err; 501 502 if (!g_audio) 503 return -EINVAL; 504 505 uac = kzalloc(sizeof(*uac), GFP_KERNEL); 506 if (!uac) 507 return -ENOMEM; 508 g_audio->uac = uac; 509 uac->audio_dev = g_audio; 510 511 params = &g_audio->params; 512 p_chmask = params->p_chmask; 513 c_chmask = params->c_chmask; 514 515 if (c_chmask) { 516 struct uac_rtd_params *prm = &uac->c_prm; 517 518 uac->c_prm.uac = uac; 519 prm->max_psize = g_audio->out_ep_maxpsize; 520 521 prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req), 522 GFP_KERNEL); 523 if (!prm->ureq) { 524 err = -ENOMEM; 525 goto fail; 526 } 527 528 prm->rbuf = kcalloc(params->req_number, prm->max_psize, 529 GFP_KERNEL); 530 if (!prm->rbuf) { 531 prm->max_psize = 0; 532 err = -ENOMEM; 533 goto fail; 534 } 535 } 536 537 if (p_chmask) { 538 struct uac_rtd_params *prm = &uac->p_prm; 539 540 uac->p_prm.uac = uac; 541 prm->max_psize = g_audio->in_ep_maxpsize; 542 543 prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req), 544 GFP_KERNEL); 545 if (!prm->ureq) { 546 err = -ENOMEM; 547 goto fail; 548 } 549 550 prm->rbuf = kcalloc(params->req_number, prm->max_psize, 551 GFP_KERNEL); 552 if (!prm->rbuf) { 553 prm->max_psize = 0; 554 err = -ENOMEM; 555 goto fail; 556 } 557 } 558 559 /* Choose any slot, with no id */ 560 err = snd_card_new(&g_audio->gadget->dev, 561 -1, NULL, THIS_MODULE, 0, &card); 562 if (err < 0) 563 goto fail; 564 565 uac->card = card; 566 567 /* 568 * Create first PCM device 569 * Create a substream only for non-zero channel streams 570 */ 571 err = snd_pcm_new(uac->card, pcm_name, 0, 572 p_chmask ? 1 : 0, c_chmask ? 1 : 0, &pcm); 573 if (err < 0) 574 goto snd_fail; 575 576 strlcpy(pcm->name, pcm_name, sizeof(pcm->name)); 577 pcm->private_data = uac; 578 uac->pcm = pcm; 579 580 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &uac_pcm_ops); 581 snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &uac_pcm_ops); 582 583 strlcpy(card->driver, card_name, sizeof(card->driver)); 584 strlcpy(card->shortname, card_name, sizeof(card->shortname)); 585 sprintf(card->longname, "%s %i", card_name, card->dev->id); 586 587 snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS, 588 snd_dma_continuous_data(GFP_KERNEL), 0, BUFF_SIZE_MAX); 589 590 err = snd_card_register(card); 591 592 if (!err) 593 return 0; 594 595 snd_fail: 596 snd_card_free(card); 597 fail: 598 kfree(uac->p_prm.ureq); 599 kfree(uac->c_prm.ureq); 600 kfree(uac->p_prm.rbuf); 601 kfree(uac->c_prm.rbuf); 602 kfree(uac); 603 604 return err; 605 } 606 EXPORT_SYMBOL_GPL(g_audio_setup); 607 608 void g_audio_cleanup(struct g_audio *g_audio) 609 { 610 struct snd_uac_chip *uac; 611 struct snd_card *card; 612 613 if (!g_audio || !g_audio->uac) 614 return; 615 616 uac = g_audio->uac; 617 card = uac->card; 618 if (card) 619 snd_card_free(card); 620 621 kfree(uac->p_prm.ureq); 622 kfree(uac->c_prm.ureq); 623 kfree(uac->p_prm.rbuf); 624 kfree(uac->c_prm.rbuf); 625 kfree(uac); 626 } 627 EXPORT_SYMBOL_GPL(g_audio_cleanup); 628 629 MODULE_LICENSE("GPL"); 630 MODULE_DESCRIPTION("USB gadget \"ALSA sound card\" utilities"); 631 MODULE_AUTHOR("Ruslan Bilovol"); 632