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 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) {
  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_hw_params(struct snd_pcm_substream *substream,
 248                                struct snd_pcm_hw_params *hw_params)
 249 {
 250         return snd_pcm_lib_malloc_pages(substream,
 251                                         params_buffer_bytes(hw_params));
 252 }
 253
 254 static int uac_pcm_hw_free(struct snd_pcm_substream *substream)
 255 {
 256         return snd_pcm_lib_free_pages(substream);
 257 }
 258
 259 static int uac_pcm_open(struct snd_pcm_substream *substream)
 260 {
 261         struct snd_uac_chip *uac = snd_pcm_substream_chip(substream);
 262         struct snd_pcm_runtime *runtime = substream->runtime;
 263         struct g_audio *audio_dev;
 264         struct uac_params *params;
 265         int p_ssize, c_ssize;
 266         int p_srate, c_srate;
 267         int p_chmask, c_chmask;
 268
 269         audio_dev = uac->audio_dev;
 270         params = &audio_dev->params;
 271         p_ssize = params->p_ssize;
 272         c_ssize = params->c_ssize;
 273         p_srate = params->p_srate;
 274         c_srate = params->c_srate;
 275         p_chmask = params->p_chmask;
 276         c_chmask = params->c_chmask;
 277         uac->p_residue = 0;
 278
 279         runtime->hw = uac_pcm_hardware;
 280
 281         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 282                 spin_lock_init(&uac->p_prm.lock);
 283                 runtime->hw.rate_min = p_srate;
 284                 switch (p_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(p_chmask);
 296                 runtime->hw.period_bytes_min = 2 * uac->p_prm.max_psize
 297                                                 / runtime->hw.periods_min;
 298         } else {
 299                 spin_lock_init(&uac->c_prm.lock);
 300                 runtime->hw.rate_min = c_srate;
 301                 switch (c_ssize) {
 302                 case 3:
 303                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S24_3LE;
 304                         break;
 305                 case 4:
 306                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S32_LE;
 307                         break;
 308                 default:
 309                         runtime->hw.formats = SNDRV_PCM_FMTBIT_S16_LE;
 310                         break;
 311                 }
 312                 runtime->hw.channels_min = num_channels(c_chmask);
 313                 runtime->hw.period_bytes_min = 2 * uac->c_prm.max_psize
 314                                                 / runtime->hw.periods_min;
 315         }
 316
 317         runtime->hw.rate_max = runtime->hw.rate_min;
 318         runtime->hw.channels_max = runtime->hw.channels_min;
 319
 320         snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
 321
 322         return 0;
 323 }
 324
 325 /* ALSA cries without these function pointers */
 326 static int uac_pcm_null(struct snd_pcm_substream *substream)
 327 {
 328         return 0;
 329 }
 330
 331 static const struct snd_pcm_ops uac_pcm_ops = {
 332         .open = uac_pcm_open,
 333         .close = uac_pcm_null,
 334         .ioctl = snd_pcm_lib_ioctl,
 335         .hw_params = uac_pcm_hw_params,
 336         .hw_free = uac_pcm_hw_free,
 337         .trigger = uac_pcm_trigger,
 338         .pointer = uac_pcm_pointer,
 339         .prepare = uac_pcm_null,
 340 };
 341
 342 static inline void free_ep(struct uac_rtd_params *prm, struct usb_ep *ep)
 343 {
 344         struct snd_uac_chip *uac = prm->uac;
 345         struct g_audio *audio_dev;
 346         struct uac_params *params;
 347         int i;
 348
 349         if (!prm->ep_enabled)
 350                 return;
 351
 352         audio_dev = uac->audio_dev;
 353         params = &audio_dev->params;
 354
 355         for (i = 0; i < params->req_number; i++) {
 356                 if (prm->ureq[i].req) {
 357                         if (usb_ep_dequeue(ep, prm->ureq[i].req))
 358                                 usb_ep_free_request(ep, prm->ureq[i].req);
 359                         /*
 360                          * If usb_ep_dequeue() cannot successfully dequeue the
 361                          * request, the request will be freed by the completion
 362                          * callback.
 363                          */
 364
 365                         prm->ureq[i].req = NULL;
 366                 }
 367         }
 368
 369         prm->ep_enabled = false;
 370
 371         if (usb_ep_disable(ep))
 372                 dev_err(uac->card->dev, "%s:%d Error!\n", __func__, __LINE__);
 373 }
 374
 375 int u_audio_start_capture(struct g_audio *audio_dev)
 376 {
 377         struct snd_uac_chip *uac = audio_dev->uac;
 378         struct usb_gadget *gadget = audio_dev->gadget;
 379         struct device *dev = &gadget->dev;
 380         struct usb_request *req;
 381         struct usb_ep *ep;
 382         struct uac_rtd_params *prm;
 383         struct uac_params *params = &audio_dev->params;
 384         int req_len, i;
 385
 386         ep = audio_dev->out_ep;
 387         prm = &uac->c_prm;
 388         config_ep_by_speed(gadget, &audio_dev->func, ep);
 389         req_len = prm->max_psize;
 390
 391         prm->ep_enabled = true;
 392         usb_ep_enable(ep);
 393
 394         for (i = 0; i < params->req_number; i++) {
 395                 if (!prm->ureq[i].req) {
 396                         req = usb_ep_alloc_request(ep, GFP_ATOMIC);
 397                         if (req == NULL)
 398                                 return -ENOMEM;
 399
 400                         prm->ureq[i].req = req;
 401                         prm->ureq[i].pp = prm;
 402
 403                         req->zero = 0;
 404                         req->context = &prm->ureq[i];
 405                         req->length = req_len;
 406                         req->complete = u_audio_iso_complete;
 407                         req->buf = prm->rbuf + i * prm->max_psize;
 408                 }
 409
 410                 if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
 411                         dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
 412         }
 413
 414         return 0;
 415 }
 416 EXPORT_SYMBOL_GPL(u_audio_start_capture);
 417
 418 void u_audio_stop_capture(struct g_audio *audio_dev)
 419 {
 420         struct snd_uac_chip *uac = audio_dev->uac;
 421
 422         free_ep(&uac->c_prm, audio_dev->out_ep);
 423 }
 424 EXPORT_SYMBOL_GPL(u_audio_stop_capture);
 425
 426 int u_audio_start_playback(struct g_audio *audio_dev)
 427 {
 428         struct snd_uac_chip *uac = audio_dev->uac;
 429         struct usb_gadget *gadget = audio_dev->gadget;
 430         struct device *dev = &gadget->dev;
 431         struct usb_request *req;
 432         struct usb_ep *ep;
 433         struct uac_rtd_params *prm;
 434         struct uac_params *params = &audio_dev->params;
 435         unsigned int factor, rate;
 436         const struct usb_endpoint_descriptor *ep_desc;
 437         int req_len, i;
 438
 439         ep = audio_dev->in_ep;
 440         prm = &uac->p_prm;
 441         config_ep_by_speed(gadget, &audio_dev->func, ep);
 442
 443         ep_desc = ep->desc;
 444
 445         /* pre-calculate the playback endpoint's interval */
 446         if (gadget->speed == USB_SPEED_FULL)
 447                 factor = 1000;
 448         else
 449                 factor = 8000;
 450
 451         /* pre-compute some values for iso_complete() */
 452         uac->p_framesize = params->p_ssize *
 453                             num_channels(params->p_chmask);
 454         rate = params->p_srate * uac->p_framesize;
 455         uac->p_interval = factor / (1 << (ep_desc->bInterval - 1));
 456         uac->p_pktsize = min_t(unsigned int, rate / uac->p_interval,
 457                                 prm->max_psize);
 458
 459         if (uac->p_pktsize < prm->max_psize)
 460                 uac->p_pktsize_residue = rate % uac->p_interval;
 461         else
 462                 uac->p_pktsize_residue = 0;
 463
 464         req_len = uac->p_pktsize;
 465         uac->p_residue = 0;
 466
 467         prm->ep_enabled = true;
 468         usb_ep_enable(ep);
 469
 470         for (i = 0; i < params->req_number; i++) {
 471                 if (!prm->ureq[i].req) {
 472                         req = usb_ep_alloc_request(ep, GFP_ATOMIC);
 473                         if (req == NULL)
 474                                 return -ENOMEM;
 475
 476                         prm->ureq[i].req = req;
 477                         prm->ureq[i].pp = prm;
 478
 479                         req->zero = 0;
 480                         req->context = &prm->ureq[i];
 481                         req->length = req_len;
 482                         req->complete = u_audio_iso_complete;
 483                         req->buf = prm->rbuf + i * prm->max_psize;
 484                 }
 485
 486                 if (usb_ep_queue(ep, prm->ureq[i].req, GFP_ATOMIC))
 487                         dev_err(dev, "%s:%d Error!\n", __func__, __LINE__);
 488         }
 489
 490         return 0;
 491 }
 492 EXPORT_SYMBOL_GPL(u_audio_start_playback);
 493
 494 void u_audio_stop_playback(struct g_audio *audio_dev)
 495 {
 496         struct snd_uac_chip *uac = audio_dev->uac;
 497
 498         free_ep(&uac->p_prm, audio_dev->in_ep);
 499 }
 500 EXPORT_SYMBOL_GPL(u_audio_stop_playback);
 501
 502 int g_audio_setup(struct g_audio *g_audio, const char *pcm_name,
 503                                         const char *card_name)
 504 {
 505         struct snd_uac_chip *uac;
 506         struct snd_card *card;
 507         struct snd_pcm *pcm;
 508         struct uac_params *params;
 509         int p_chmask, c_chmask;
 510         int err;
 511
 512         if (!g_audio)
 513                 return -EINVAL;
 514
 515         uac = kzalloc(sizeof(*uac), GFP_KERNEL);
 516         if (!uac)
 517                 return -ENOMEM;
 518         g_audio->uac = uac;
 519         uac->audio_dev = g_audio;
 520
 521         params = &g_audio->params;
 522         p_chmask = params->p_chmask;
 523         c_chmask = params->c_chmask;
 524
 525         if (c_chmask) {
 526                 struct uac_rtd_params *prm = &uac->c_prm;
 527
 528                 uac->c_prm.uac = uac;
 529                 prm->max_psize = g_audio->out_ep_maxpsize;
 530
 531                 prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req),
 532                                 GFP_KERNEL);
 533                 if (!prm->ureq) {
 534                         err = -ENOMEM;
 535                         goto fail;
 536                 }
 537
 538                 prm->rbuf = kcalloc(params->req_number, prm->max_psize,
 539                                 GFP_KERNEL);
 540                 if (!prm->rbuf) {
 541                         prm->max_psize = 0;
 542                         err = -ENOMEM;
 543                         goto fail;
 544                 }
 545         }
 546
 547         if (p_chmask) {
 548                 struct uac_rtd_params *prm = &uac->p_prm;
 549
 550                 uac->p_prm.uac = uac;
 551                 prm->max_psize = g_audio->in_ep_maxpsize;
 552
 553                 prm->ureq = kcalloc(params->req_number, sizeof(struct uac_req),
 554                                 GFP_KERNEL);
 555                 if (!prm->ureq) {
 556                         err = -ENOMEM;
 557                         goto fail;
 558                 }
 559
 560                 prm->rbuf = kcalloc(params->req_number, prm->max_psize,
 561                                 GFP_KERNEL);
 562                 if (!prm->rbuf) {
 563                         prm->max_psize = 0;
 564                         err = -ENOMEM;
 565                         goto fail;
 566                 }
 567         }
 568
 569         /* Choose any slot, with no id */
 570         err = snd_card_new(&g_audio->gadget->dev,
 571                         -1, NULL, THIS_MODULE, 0, &card);
 572         if (err < 0)
 573                 goto fail;
 574
 575         uac->card = card;
 576
 577         /*
 578          * Create first PCM device
 579          * Create a substream only for non-zero channel streams
 580          */
 581         err = snd_pcm_new(uac->card, pcm_name, 0,
 582                                p_chmask ? 1 : 0, c_chmask ? 1 : 0, &pcm);
 583         if (err < 0)
 584                 goto snd_fail;
 585
 586         strlcpy(pcm->name, pcm_name, sizeof(pcm->name));
 587         pcm->private_data = uac;
 588         uac->pcm = pcm;
 589
 590         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &uac_pcm_ops);
 591         snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &uac_pcm_ops);
 592
 593         strlcpy(card->driver, card_name, sizeof(card->driver));
 594         strlcpy(card->shortname, card_name, sizeof(card->shortname));
 595         sprintf(card->longname, "%s %i", card_name, card->dev->id);
 596
 597         snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
 598                 snd_dma_continuous_data(GFP_KERNEL), 0, BUFF_SIZE_MAX);
 599
 600         err = snd_card_register(card);
 601
 602         if (!err)
 603                 return 0;
 604
 605 snd_fail:
 606         snd_card_free(card);
 607 fail:
 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         return err;
 615 }
 616 EXPORT_SYMBOL_GPL(g_audio_setup);
 617
 618 void g_audio_cleanup(struct g_audio *g_audio)
 619 {
 620         struct snd_uac_chip *uac;
 621         struct snd_card *card;
 622
 623         if (!g_audio || !g_audio->uac)
 624                 return;
 625
 626         uac = g_audio->uac;
 627         card = uac->card;
 628         if (card)
 629                 snd_card_free(card);
 630
 631         kfree(uac->p_prm.ureq);
 632         kfree(uac->c_prm.ureq);
 633         kfree(uac->p_prm.rbuf);
 634         kfree(uac->c_prm.rbuf);
 635         kfree(uac);
 636 }
 637 EXPORT_SYMBOL_GPL(g_audio_cleanup);
 638
 639 MODULE_LICENSE("GPL");
 640 MODULE_DESCRIPTION("USB gadget \"ALSA sound card\" utilities");
 641 MODULE_AUTHOR("Ruslan Bilovol");