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_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");