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 || 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_open(struct snd_pcm_substream *substream)
 243 {
 244         struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
 245         struct snd_pcm_runtime *runtime = substream->runtime;
 246         struct g_audio *audio_dev;
 247         struct uac_params *params;
 248         int p_ssize, c_ssize;
 249         int p_srate, c_srate;
 250         int p_chmask, c_chmask;
 251
 252         audio_dev = uac->audio_dev;
 253         params = &audio_dev->params;
 254         p_ssize = params->p_ssize;
 255         c_ssize = params->c_ssize;
 256         p_srate = params->p_srate;
 257         c_srate = params->c_srate;
 258         p_chmask = params->p_chmask;
 259         c_chmask = params->c_chmask;
 260         uac->p_residue = 0;
 261
 262         runtime->hw = uac_pcm_hardware;
 263
 264         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 265                 spin_lock_init(&uac->p_prm.lock);
 266                 runtime->hw.rate_min = p_srate;
 267                 switch (p_ssize) {
 268                 case 3:
 269                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;
 270                         break;
 271                 case 4:
 272                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;
 273                         break;
 274                 default:
 275                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
 276                         break;
 277                 }
 278                 runtime->hw.channels_min = num_channels(p_chmask);
 279                 runtime->hw.period_bytes_min = 2 * uac->p_prm.max_psize
 280                                                 / runtime->hw.periods_min;
 281         } else {
 282                 spin_lock_init(&uac->c_prm.lock);
 283                 runtime->hw.rate_min = c_srate;
 284                 switch (c_ssize) {
 285                 case 3:
 286                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;
 287                         break;
 288                 case 4:
 289                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;
 290                         break;
 291                 default:
 292                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
 293                         break;
 294                 }
 295                 runtime->hw.channels_min = num_channels(c_chmask);
 296                 runtime->hw.period_bytes_min = 2 * uac->c_prm.max_psize
 297                                                 / runtime->hw.periods_min;
 298         }
 299
 300         runtime->hw.rate_max = runtime->hw.rate_min;
 301         runtime->hw.channels_max = runtime->hw.channels_min;
 302
 303         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
 304
 305         return 0;
 306 }
 307
 308 /* ALSA cries without these function pointers */
 309 static int uac_pcm_null(struct snd_pcm_substream *substream)
 310 {
 311         return 0;
 312 }
 313
 314 static const struct snd_pcm_ops uac_pcm_ops = {
 315         .open = uac_pcm_open,
 316         .close = uac_pcm_null,
 317         .trigger = uac_pcm_trigger,
 318         .pointer = uac_pcm_pointer,
 319         .prepare = uac_pcm_null,
 320 };
 321
 322 static inline void free_ep(struct uac_rtd_params *prm, struct usb_ep *ep)
 323 {
 324         struct snd_uac_chip *uac = prm->uac;
 325         struct g_audio *audio_dev;
 326         struct uac_params *params;
 327         int i;
 328
 329         if (!prm->ep_enabled)
 330                 return;
 331
 332         prm->ep_enabled = false;
 333
 334         audio_dev = uac->audio_dev;
 335         params = &audio_dev->params;
 336
 337         for (i = 0; i < params->req_number; i++) {
 338                 if (prm->ureq[i].req) {
 339                         usb_ep_dequeue(ep, prm->ureq[i].req);
 340                         usb_ep_free_request(ep, prm->ureq[i].req);
 341                         prm->ureq[i].req = NULL;
 342                 }
 343         }
 344
 345         if (usb_ep_disable(ep))
 346                 dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__);
 347 }
 348
 349
 350 int u_audio_start_capture(struct g_audio *audio_dev)
 351 {
 352         struct snd_uac_chip *uac = audio_dev->uac;
 353         struct usb_gadget *gadget = audio_dev->gadget;
 354         struct device *dev = &gadget->dev;
 355         struct usb_request *req;
 356         struct usb_ep *ep;
 357         struct uac_rtd_params *prm;
 358         struct uac_params *params = &audio_dev->params;
 359         int req_len, i;
 360
 361         ep = audio_dev->out_ep;
 362         prm = &uac->c_prm;
 363         config_ep_by_speed(gadget, &audio_dev->func, ep);
 364         req_len = prm->max_psize;
 365
 366         prm->ep_enabled = true;
 367         usb_ep_enable(ep);
 368
 369         for (i = 0; i < params->req_number; i++) {
 370                 if (!prm->ureq[i].req) {
 371                         req = usb_ep_alloc_request(ep, GFP_ATOMIC);
 372                         if (req == NULL)
 373                                 return -ENOMEM;
 374
 375                         prm->ureq[i].req = req;
 376                         prm->ureq[i].pp = prm;
 377
 378                         req->zero = 0;
 379                         req->context = &prm->ureq[i];
 380                         req->length = req_len;
 381                         req->complete = u_audio_iso_complete;
 382                         req->buf = prm->rbuf + i * prm->max_psize;
 383                 }
 384
 385                 if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
 386                         dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
 387         }
 388
 389         return 0;
 390 }
 391 EXPORT_SYMBOL_GPL(u_audio_start_capture);
 392
 393 void u_audio_stop_capture(struct g_audio *audio_dev)
 394 {
 395         struct snd_uac_chip *uac = audio_dev->uac;
 396
 397         free_ep(&uac->c_prm, audio_dev->out_ep);
 398 }
 399 EXPORT_SYMBOL_GPL(u_audio_stop_capture);
 400
 401 int u_audio_start_playback(struct g_audio *audio_dev)
 402 {
 403         struct snd_uac_chip *uac = audio_dev->uac;
 404         struct usb_gadget *gadget = audio_dev->gadget;
 405         struct device *dev = &gadget->dev;
 406         struct usb_request *req;
 407         struct usb_ep *ep;
 408         struct uac_rtd_params *prm;
 409         struct uac_params *params = &audio_dev->params;
 410         unsigned int factor;
 411         const struct usb_endpoint_descriptor *ep_desc;
 412         int req_len, i;
 413
 414         ep = audio_dev->in_ep;
 415         prm = &uac->p_prm;
 416         config_ep_by_speed(gadget, &audio_dev->func, ep);
 417
 418         ep_desc = ep->desc;
 419
 420         /* pre-calculate the playback endpoint's interval */
 421         if (gadget->speed == USB_SPEED_FULL)
 422                 factor = 1000;
 423         else
 424                 factor = 8000;
 425
 426         /* pre-compute some values for iso_complete() */
 427         uac->p_framesize = params->p_ssize *
 428                             num_channels(params->p_chmask);
 429         uac->p_interval = factor / (1 << (ep_desc->bInterval - 1));
 430         uac->p_pktsize = min_t(unsigned int,
 431                                 uac->p_framesize *
 432                                         (params->p_srate / uac->p_interval),
 433                                 prm->max_psize);
 434
 435         if (uac->p_pktsize < prm->max_psize)
 436                 uac->p_pktsize_residue = uac->p_framesize *
 437                         (params->p_srate % uac->p_interval);
 438         else
 439                 uac->p_pktsize_residue = 0;
 440
 441         req_len = uac->p_pktsize;
 442         uac->p_residue = 0;
 443
 444         prm->ep_enabled = true;
 445         usb_ep_enable(ep);
 446
 447         for (i = 0; i < params->req_number; i++) {
 448                 if (!prm->ureq[i].req) {
 449                         req = usb_ep_alloc_request(ep, GFP_ATOMIC);
 450                         if (req == NULL)
 451                                 return -ENOMEM;
 452
 453                         prm->ureq[i].req = req;
 454                         prm->ureq[i].pp = prm;
 455
 456                         req->zero = 0;
 457                         req->context = &prm->ureq[i];
 458                         req->length = req_len;
 459                         req->complete = u_audio_iso_complete;
 460                         req->buf = prm->rbuf + i * prm->max_psize;
 461                 }
 462
 463                 if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
 464                         dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
 465         }
 466
 467         return 0;
 468 }
 469 EXPORT_SYMBOL_GPL(u_audio_start_playback);
 470
 471 void u_audio_stop_playback(struct g_audio *audio_dev)
 472 {
 473         struct snd_uac_chip *uac = audio_dev->uac;
 474
 475         free_ep(&uac->p_prm, audio_dev->in_ep);
 476 }
 477 EXPORT_SYMBOL_GPL(u_audio_stop_playback);
 478
 479 int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
 480                                         const char *card_name)
 481 {
 482         struct snd_uac_chip *uac;
 483         struct snd_card *card;
 484         struct snd_pcm *pcm;
 485         struct uac_params *params;
 486         int p_chmask, c_chmask;
 487         int err;
 488
 489         if (!g_audio)
 490                 return -EINVAL;
 491
 492         uac = kzalloc(sizeof(*uac), GFP_KERNEL);
 493         if (!uac)
 494                 return -ENOMEM;
 495         g_audio->uac = uac;
 496         uac->audio_dev = g_audio;
 497
 498         params = &g_audio->params;
 499         p_chmask = params->p_chmask;
 500         c_chmask = params->c_chmask;
 501
 502         if (c_chmask) {
 503                 struct uac_rtd_params *prm = &uac->c_prm;
 504
 505                 uac->c_prm.uac = uac;
 506                 prm->max_psize = g_audio->out_ep_maxpsize;
 507
 508                 prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req),
 509                                 GFP_KERNEL);
 510                 if (!prm->ureq) {
 511                         err = -ENOMEM;
 512                         goto fail;
 513                 }
 514
 515                 prm->rbuf = kcalloc(params->req_number, prm->max_psize,
 516                                 GFP_KERNEL);
 517                 if (!prm->rbuf) {
 518                         prm->max_psize = 0;
 519                         err = -ENOMEM;
 520                         goto fail;
 521                 }
 522         }
 523
 524         if (p_chmask) {
 525                 struct uac_rtd_params *prm = &uac->p_prm;
 526
 527                 uac->p_prm.uac = uac;
 528                 prm->max_psize = g_audio->in_ep_maxpsize;
 529
 530                 prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req),
 531                                 GFP_KERNEL);
 532                 if (!prm->ureq) {
 533                         err = -ENOMEM;
 534                         goto fail;
 535                 }
 536
 537                 prm->rbuf = kcalloc(params->req_number, prm->max_psize,
 538                                 GFP_KERNEL);
 539                 if (!prm->rbuf) {
 540                         prm->max_psize = 0;
 541                         err = -ENOMEM;
 542                         goto fail;
 543                 }
 544         }
 545
 546         /* Choose any slot, with no id */
 547         err = snd_card_new(&g_audio->gadget->dev,
 548                         -1, NULL, THIS_MODULE, 0, &card);
 549         if (err < 0)
 550                 goto fail;
 551
 552         uac->card = card;
 553
 554         /*
 555          * Create first PCM device
 556          * Create a substream only for non-zero channel streams
 557          */
 558         err = snd_pcm_new(uac->card, pcm_name, 0,
 559                                p_chmask ? 1 : 0, c_chmask ? 1 : 0, &pcm);
 560         if (err < 0)
 561                 goto snd_fail;
 562
 563         strlcpy(pcm->name, pcm_name, sizeof(pcm->name));
 564         pcm->private_data = uac;
 565         uac->pcm = pcm;
 566
 567         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &uac_pcm_ops);
 568         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &uac_pcm_ops);
 569
 570         strlcpy(card->driver, card_name, sizeof(card->driver));
 571         strlcpy(card->shortname, card_name, sizeof(card->shortname));
 572         sprintf(card->longname, "%s %i", card_name, card->dev->id);
 573
 574         snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
 575                                        NULL, 0, BUFF_SIZE_MAX);
 576
 577         err = snd_card_register(card);
 578
 579         if (!err)
 580                 return 0;
 581
 582 snd_fail:
 583         snd_card_free(card);
 584 fail:
 585         kfree(uac->p_prm.ureq);
 586         kfree(uac->c_prm.ureq);
 587         kfree(uac->p_prm.rbuf);
 588         kfree(uac->c_prm.rbuf);
 589         kfree(uac);
 590
 591         return err;
 592 }
 593 EXPORT_SYMBOL_GPL(g_audio_setup);
 594
 595 void g_audio_cleanup(struct g_audio *g_audio)
 596 {
 597         struct snd_uac_chip *uac;
 598         struct snd_card *card;
 599
 600         if (!g_audio || !g_audio->uac)
 601                 return;
 602
 603         uac = g_audio->uac;
 604         card = uac->card;
 605         if (card)
 606                 snd_card_free(card);
 607
 608         kfree(uac->p_prm.ureq);
 609         kfree(uac->c_prm.ureq);
 610         kfree(uac->p_prm.rbuf);
 611         kfree(uac->c_prm.rbuf);
 612         kfree(uac);
 613 }
 614 EXPORT_SYMBOL_GPL(g_audio_cleanup);
 615
 616 MODULE_LICENSE("GPL");
 617 MODULE_DESCRIPTION("USB gadget \"ALSA sound card\" utilities");
 618 MODULE_AUTHOR("Ruslan Bilovol");