drivers/usb/gadget/function/u_audio.c

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