sound/usb/endpoint.c

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This source file includes following definitions.
get_usb_full_speed_rate
get_usb_high_speed_rate
release_urb_ctx
usb_error_string
snd_usb_endpoint_implicit_feedback_sink
snd_usb_endpoint_next_packet_size
retire_outbound_urb
retire_inbound_urb
prepare_silent_urb
prepare_outbound_urb
prepare_inbound_urb
queue_pending_output_urbs
snd_complete_urb
snd_usb_add_endpoint
wait_clear_urbs
snd_usb_endpoint_sync_pending_stop
deactivate_urbs
release_urbs
data_ep_set_params
sync_ep_set_params
snd_usb_endpoint_set_params
snd_usb_endpoint_start
snd_usb_endpoint_stop
snd_usb_endpoint_deactivate
snd_usb_endpoint_release
snd_usb_endpoint_free
snd_usb_handle_sync_urb
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  */
   4 
   5 #include <linux/gfp.h>
   6 #include <linux/init.h>
   7 #include <linux/ratelimit.h>
   8 #include <linux/usb.h>
   9 #include <linux/usb/audio.h>
  10 #include <linux/slab.h>
  11 
  12 #include <sound/core.h>
  13 #include <sound/pcm.h>
  14 #include <sound/pcm_params.h>
  15 
  16 #include "usbaudio.h"
  17 #include "helper.h"
  18 #include "card.h"
  19 #include "endpoint.h"
  20 #include "pcm.h"
  21 #include "quirks.h"
  22 
  23 #define EP_FLAG_RUNNING         1
  24 #define EP_FLAG_STOPPING        2
  25 
  26 /*
  27  * snd_usb_endpoint is a model that abstracts everything related to an
  28  * USB endpoint and its streaming.
  29  *
  30  * There are functions to activate and deactivate the streaming URBs and
  31  * optional callbacks to let the pcm logic handle the actual content of the
  32  * packets for playback and record. Thus, the bus streaming and the audio
  33  * handlers are fully decoupled.
  34  *
  35  * There are two different types of endpoints in audio applications.
  36  *
  37  * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
  38  * inbound and outbound traffic.
  39  *
  40  * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
  41  * expect the payload to carry Q10.14 / Q16.16 formatted sync information
  42  * (3 or 4 bytes).
  43  *
  44  * Each endpoint has to be configured prior to being used by calling
  45  * snd_usb_endpoint_set_params().
  46  *
  47  * The model incorporates a reference counting, so that multiple users
  48  * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
  49  * only the first user will effectively start the URBs, and only the last
  50  * one to stop it will tear the URBs down again.
  51  */
  52 
  53 /*
  54  * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
  55  * this will overflow at approx 524 kHz
  56  */
  57 static inline unsigned get_usb_full_speed_rate(unsigned int rate)
  58 {
  59         return ((rate << 13) + 62) / 125;
  60 }
  61 
  62 /*
  63  * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
  64  * this will overflow at approx 4 MHz
  65  */
  66 static inline unsigned get_usb_high_speed_rate(unsigned int rate)
  67 {
  68         return ((rate << 10) + 62) / 125;
  69 }
  70 
  71 /*
  72  * release a urb data
  73  */
  74 static void release_urb_ctx(struct snd_urb_ctx *u)
  75 {
  76         if (u->buffer_size)
  77                 usb_free_coherent(u->ep->chip->dev, u->buffer_size,
  78                                   u->urb->transfer_buffer,
  79                                   u->urb->transfer_dma);
  80         usb_free_urb(u->urb);
  81         u->urb = NULL;
  82 }
  83 
  84 static const char *usb_error_string(int err)
  85 {
  86         switch (err) {
  87         case -ENODEV:
  88                 return "no device";
  89         case -ENOENT:
  90                 return "endpoint not enabled";
  91         case -EPIPE:
  92                 return "endpoint stalled";
  93         case -ENOSPC:
  94                 return "not enough bandwidth";
  95         case -ESHUTDOWN:
  96                 return "device disabled";
  97         case -EHOSTUNREACH:
  98                 return "device suspended";
  99         case -EINVAL:
 100         case -EAGAIN:
 101         case -EFBIG:
 102         case -EMSGSIZE:
 103                 return "internal error";
 104         default:
 105                 return "unknown error";
 106         }
 107 }
 108 
 109 /**
 110  * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
 111  *
 112  * @ep: The snd_usb_endpoint
 113  *
 114  * Determine whether an endpoint is driven by an implicit feedback
 115  * data endpoint source.
 116  */
 117 int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
 118 {
 119         return  ep->sync_master &&
 120                 ep->sync_master->type == SND_USB_ENDPOINT_TYPE_DATA &&
 121                 ep->type == SND_USB_ENDPOINT_TYPE_DATA &&
 122                 usb_pipeout(ep->pipe);
 123 }
 124 
 125 /*
 126  * For streaming based on information derived from sync endpoints,
 127  * prepare_outbound_urb_sizes() will call next_packet_size() to
 128  * determine the number of samples to be sent in the next packet.
 129  *
 130  * For implicit feedback, next_packet_size() is unused.
 131  */
 132 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep)
 133 {
 134         unsigned long flags;
 135         int ret;
 136 
 137         if (ep->fill_max)
 138                 return ep->maxframesize;
 139 
 140         spin_lock_irqsave(&ep->lock, flags);
 141         ep->phase = (ep->phase & 0xffff)
 142                 + (ep->freqm << ep->datainterval);
 143         ret = min(ep->phase >> 16, ep->maxframesize);
 144         spin_unlock_irqrestore(&ep->lock, flags);
 145 
 146         return ret;
 147 }
 148 
 149 static void retire_outbound_urb(struct snd_usb_endpoint *ep,
 150                                 struct snd_urb_ctx *urb_ctx)
 151 {
 152         if (ep->retire_data_urb)
 153                 ep->retire_data_urb(ep->data_subs, urb_ctx->urb);
 154 }
 155 
 156 static void retire_inbound_urb(struct snd_usb_endpoint *ep,
 157                                struct snd_urb_ctx *urb_ctx)
 158 {
 159         struct urb *urb = urb_ctx->urb;
 160 
 161         if (unlikely(ep->skip_packets > 0)) {
 162                 ep->skip_packets--;
 163                 return;
 164         }
 165 
 166         if (ep->sync_slave)
 167                 snd_usb_handle_sync_urb(ep->sync_slave, ep, urb);
 168 
 169         if (ep->retire_data_urb)
 170                 ep->retire_data_urb(ep->data_subs, urb);
 171 }
 172 
 173 static void prepare_silent_urb(struct snd_usb_endpoint *ep,
 174                                struct snd_urb_ctx *ctx)
 175 {
 176         struct urb *urb = ctx->urb;
 177         unsigned int offs = 0;
 178         unsigned int extra = 0;
 179         __le32 packet_length;
 180         int i;
 181 
 182         /* For tx_length_quirk, put packet length at start of packet */
 183         if (ep->chip->tx_length_quirk)
 184                 extra = sizeof(packet_length);
 185 
 186         for (i = 0; i < ctx->packets; ++i) {
 187                 unsigned int offset;
 188                 unsigned int length;
 189                 int counts;
 190 
 191                 if (ctx->packet_size[i])
 192                         counts = ctx->packet_size[i];
 193                 else
 194                         counts = snd_usb_endpoint_next_packet_size(ep);
 195 
 196                 length = counts * ep->stride; /* number of silent bytes */
 197                 offset = offs * ep->stride + extra * i;
 198                 urb->iso_frame_desc[i].offset = offset;
 199                 urb->iso_frame_desc[i].length = length + extra;
 200                 if (extra) {
 201                         packet_length = cpu_to_le32(length);
 202                         memcpy(urb->transfer_buffer + offset,
 203                                &packet_length, sizeof(packet_length));
 204                 }
 205                 memset(urb->transfer_buffer + offset + extra,
 206                        ep->silence_value, length);
 207                 offs += counts;
 208         }
 209 
 210         urb->number_of_packets = ctx->packets;
 211         urb->transfer_buffer_length = offs * ep->stride + ctx->packets * extra;
 212 }
 213 
 214 /*
 215  * Prepare a PLAYBACK urb for submission to the bus.
 216  */
 217 static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
 218                                  struct snd_urb_ctx *ctx)
 219 {
 220         struct urb *urb = ctx->urb;
 221         unsigned char *cp = urb->transfer_buffer;
 222 
 223         urb->dev = ep->chip->dev; /* we need to set this at each time */
 224 
 225         switch (ep->type) {
 226         case SND_USB_ENDPOINT_TYPE_DATA:
 227                 if (ep->prepare_data_urb) {
 228                         ep->prepare_data_urb(ep->data_subs, urb);
 229                 } else {
 230                         /* no data provider, so send silence */
 231                         prepare_silent_urb(ep, ctx);
 232                 }
 233                 break;
 234 
 235         case SND_USB_ENDPOINT_TYPE_SYNC:
 236                 if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
 237                         /*
 238                          * fill the length and offset of each urb descriptor.
 239                          * the fixed 12.13 frequency is passed as 16.16 through the pipe.
 240                          */
 241                         urb->iso_frame_desc[0].length = 4;
 242                         urb->iso_frame_desc[0].offset = 0;
 243                         cp[0] = ep->freqn;
 244                         cp[1] = ep->freqn >> 8;
 245                         cp[2] = ep->freqn >> 16;
 246                         cp[3] = ep->freqn >> 24;
 247                 } else {
 248                         /*
 249                          * fill the length and offset of each urb descriptor.
 250                          * the fixed 10.14 frequency is passed through the pipe.
 251                          */
 252                         urb->iso_frame_desc[0].length = 3;
 253                         urb->iso_frame_desc[0].offset = 0;
 254                         cp[0] = ep->freqn >> 2;
 255                         cp[1] = ep->freqn >> 10;
 256                         cp[2] = ep->freqn >> 18;
 257                 }
 258 
 259                 break;
 260         }
 261 }
 262 
 263 /*
 264  * Prepare a CAPTURE or SYNC urb for submission to the bus.
 265  */
 266 static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep,
 267                                        struct snd_urb_ctx *urb_ctx)
 268 {
 269         int i, offs;
 270         struct urb *urb = urb_ctx->urb;
 271 
 272         urb->dev = ep->chip->dev; /* we need to set this at each time */
 273 
 274         switch (ep->type) {
 275         case SND_USB_ENDPOINT_TYPE_DATA:
 276                 offs = 0;
 277                 for (i = 0; i < urb_ctx->packets; i++) {
 278                         urb->iso_frame_desc[i].offset = offs;
 279                         urb->iso_frame_desc[i].length = ep->curpacksize;
 280                         offs += ep->curpacksize;
 281                 }
 282 
 283                 urb->transfer_buffer_length = offs;
 284                 urb->number_of_packets = urb_ctx->packets;
 285                 break;
 286 
 287         case SND_USB_ENDPOINT_TYPE_SYNC:
 288                 urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
 289                 urb->iso_frame_desc[0].offset = 0;
 290                 break;
 291         }
 292 }
 293 
 294 /*
 295  * Send output urbs that have been prepared previously. URBs are dequeued
 296  * from ep->ready_playback_urbs and in case there there aren't any available
 297  * or there are no packets that have been prepared, this function does
 298  * nothing.
 299  *
 300  * The reason why the functionality of sending and preparing URBs is separated
 301  * is that host controllers don't guarantee the order in which they return
 302  * inbound and outbound packets to their submitters.
 303  *
 304  * This function is only used for implicit feedback endpoints. For endpoints
 305  * driven by dedicated sync endpoints, URBs are immediately re-submitted
 306  * from their completion handler.
 307  */
 308 static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
 309 {
 310         while (test_bit(EP_FLAG_RUNNING, &ep->flags)) {
 311 
 312                 unsigned long flags;
 313                 struct snd_usb_packet_info *uninitialized_var(packet);
 314                 struct snd_urb_ctx *ctx = NULL;
 315                 int err, i;
 316 
 317                 spin_lock_irqsave(&ep->lock, flags);
 318                 if (ep->next_packet_read_pos != ep->next_packet_write_pos) {
 319                         packet = ep->next_packet + ep->next_packet_read_pos;
 320                         ep->next_packet_read_pos++;
 321                         ep->next_packet_read_pos %= MAX_URBS;
 322 
 323                         /* take URB out of FIFO */
 324                         if (!list_empty(&ep->ready_playback_urbs))
 325                                 ctx = list_first_entry(&ep->ready_playback_urbs,
 326                                                struct snd_urb_ctx, ready_list);
 327                 }
 328                 spin_unlock_irqrestore(&ep->lock, flags);
 329 
 330                 if (ctx == NULL)
 331                         return;
 332 
 333                 list_del_init(&ctx->ready_list);
 334 
 335                 /* copy over the length information */
 336                 for (i = 0; i < packet->packets; i++)
 337                         ctx->packet_size[i] = packet->packet_size[i];
 338 
 339                 /* call the data handler to fill in playback data */
 340                 prepare_outbound_urb(ep, ctx);
 341 
 342                 err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
 343                 if (err < 0)
 344                         usb_audio_err(ep->chip,
 345                                 "Unable to submit urb #%d: %d (urb %p)\n",
 346                                 ctx->index, err, ctx->urb);
 347                 else
 348                         set_bit(ctx->index, &ep->active_mask);
 349         }
 350 }
 351 
 352 /*
 353  * complete callback for urbs
 354  */
 355 static void snd_complete_urb(struct urb *urb)
 356 {
 357         struct snd_urb_ctx *ctx = urb->context;
 358         struct snd_usb_endpoint *ep = ctx->ep;
 359         struct snd_pcm_substream *substream;
 360         unsigned long flags;
 361         int err;
 362 
 363         if (unlikely(urb->status == -ENOENT ||          /* unlinked */
 364                      urb->status == -ENODEV ||          /* device removed */
 365                      urb->status == -ECONNRESET ||      /* unlinked */
 366                      urb->status == -ESHUTDOWN))        /* device disabled */
 367                 goto exit_clear;
 368         /* device disconnected */
 369         if (unlikely(atomic_read(&ep->chip->shutdown)))
 370                 goto exit_clear;
 371 
 372         if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
 373                 goto exit_clear;
 374 
 375         if (usb_pipeout(ep->pipe)) {
 376                 retire_outbound_urb(ep, ctx);
 377                 /* can be stopped during retire callback */
 378                 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
 379                         goto exit_clear;
 380 
 381                 if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
 382                         spin_lock_irqsave(&ep->lock, flags);
 383                         list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
 384                         spin_unlock_irqrestore(&ep->lock, flags);
 385                         queue_pending_output_urbs(ep);
 386 
 387                         goto exit_clear;
 388                 }
 389 
 390                 prepare_outbound_urb(ep, ctx);
 391                 /* can be stopped during prepare callback */
 392                 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
 393                         goto exit_clear;
 394         } else {
 395                 retire_inbound_urb(ep, ctx);
 396                 /* can be stopped during retire callback */
 397                 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
 398                         goto exit_clear;
 399 
 400                 prepare_inbound_urb(ep, ctx);
 401         }
 402 
 403         err = usb_submit_urb(urb, GFP_ATOMIC);
 404         if (err == 0)
 405                 return;
 406 
 407         usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
 408         if (ep->data_subs && ep->data_subs->pcm_substream) {
 409                 substream = ep->data_subs->pcm_substream;
 410                 snd_pcm_stop_xrun(substream);
 411         }
 412 
 413 exit_clear:
 414         clear_bit(ctx->index, &ep->active_mask);
 415 }
 416 
 417 /**
 418  * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
 419  *
 420  * @chip: The chip
 421  * @alts: The USB host interface
 422  * @ep_num: The number of the endpoint to use
 423  * @direction: SNDRV_PCM_STREAM_PLAYBACK or SNDRV_PCM_STREAM_CAPTURE
 424  * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
 425  *
 426  * If the requested endpoint has not been added to the given chip before,
 427  * a new instance is created. Otherwise, a pointer to the previoulsy
 428  * created instance is returned. In case of any error, NULL is returned.
 429  *
 430  * New endpoints will be added to chip->ep_list and must be freed by
 431  * calling snd_usb_endpoint_free().
 432  *
 433  * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
 434  * bNumEndpoints > 1 beforehand.
 435  */
 436 struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
 437                                               struct usb_host_interface *alts,
 438                                               int ep_num, int direction, int type)
 439 {
 440         struct snd_usb_endpoint *ep;
 441         int is_playback = direction == SNDRV_PCM_STREAM_PLAYBACK;
 442 
 443         if (WARN_ON(!alts))
 444                 return NULL;
 445 
 446         mutex_lock(&chip->mutex);
 447 
 448         list_for_each_entry(ep, &chip->ep_list, list) {
 449                 if (ep->ep_num == ep_num &&
 450                     ep->iface == alts->desc.bInterfaceNumber &&
 451                     ep->altsetting == alts->desc.bAlternateSetting) {
 452                         usb_audio_dbg(ep->chip,
 453                                       "Re-using EP %x in iface %d,%d @%p\n",
 454                                         ep_num, ep->iface, ep->altsetting, ep);
 455                         goto __exit_unlock;
 456                 }
 457         }
 458 
 459         usb_audio_dbg(chip, "Creating new %s %s endpoint #%x\n",
 460                     is_playback ? "playback" : "capture",
 461                     type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync",
 462                     ep_num);
 463 
 464         ep = kzalloc(sizeof(*ep), GFP_KERNEL);
 465         if (!ep)
 466                 goto __exit_unlock;
 467 
 468         ep->chip = chip;
 469         spin_lock_init(&ep->lock);
 470         ep->type = type;
 471         ep->ep_num = ep_num;
 472         ep->iface = alts->desc.bInterfaceNumber;
 473         ep->altsetting = alts->desc.bAlternateSetting;
 474         INIT_LIST_HEAD(&ep->ready_playback_urbs);
 475         ep_num &= USB_ENDPOINT_NUMBER_MASK;
 476 
 477         if (is_playback)
 478                 ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
 479         else
 480                 ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
 481 
 482         if (type == SND_USB_ENDPOINT_TYPE_SYNC) {
 483                 if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
 484                     get_endpoint(alts, 1)->bRefresh >= 1 &&
 485                     get_endpoint(alts, 1)->bRefresh <= 9)
 486                         ep->syncinterval = get_endpoint(alts, 1)->bRefresh;
 487                 else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
 488                         ep->syncinterval = 1;
 489                 else if (get_endpoint(alts, 1)->bInterval >= 1 &&
 490                          get_endpoint(alts, 1)->bInterval <= 16)
 491                         ep->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
 492                 else
 493                         ep->syncinterval = 3;
 494 
 495                 ep->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize);
 496         }
 497 
 498         list_add_tail(&ep->list, &chip->ep_list);
 499 
 500 __exit_unlock:
 501         mutex_unlock(&chip->mutex);
 502 
 503         return ep;
 504 }
 505 
 506 /*
 507  *  wait until all urbs are processed.
 508  */
 509 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
 510 {
 511         unsigned long end_time = jiffies + msecs_to_jiffies(1000);
 512         int alive;
 513 
 514         do {
 515                 alive = bitmap_weight(&ep->active_mask, ep->nurbs);
 516                 if (!alive)
 517                         break;
 518 
 519                 schedule_timeout_uninterruptible(1);
 520         } while (time_before(jiffies, end_time));
 521 
 522         if (alive)
 523                 usb_audio_err(ep->chip,
 524                         "timeout: still %d active urbs on EP #%x\n",
 525                         alive, ep->ep_num);
 526         clear_bit(EP_FLAG_STOPPING, &ep->flags);
 527 
 528         ep->data_subs = NULL;
 529         ep->sync_slave = NULL;
 530         ep->retire_data_urb = NULL;
 531         ep->prepare_data_urb = NULL;
 532 
 533         return 0;
 534 }
 535 
 536 /* sync the pending stop operation;
 537  * this function itself doesn't trigger the stop operation
 538  */
 539 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
 540 {
 541         if (ep && test_bit(EP_FLAG_STOPPING, &ep->flags))
 542                 wait_clear_urbs(ep);
 543 }
 544 
 545 /*
 546  * unlink active urbs.
 547  */
 548 static int deactivate_urbs(struct snd_usb_endpoint *ep, bool force)
 549 {
 550         unsigned int i;
 551 
 552         if (!force && atomic_read(&ep->chip->shutdown)) /* to be sure... */
 553                 return -EBADFD;
 554 
 555         clear_bit(EP_FLAG_RUNNING, &ep->flags);
 556 
 557         INIT_LIST_HEAD(&ep->ready_playback_urbs);
 558         ep->next_packet_read_pos = 0;
 559         ep->next_packet_write_pos = 0;
 560 
 561         for (i = 0; i < ep->nurbs; i++) {
 562                 if (test_bit(i, &ep->active_mask)) {
 563                         if (!test_and_set_bit(i, &ep->unlink_mask)) {
 564                                 struct urb *u = ep->urb[i].urb;
 565                                 usb_unlink_urb(u);
 566                         }
 567                 }
 568         }
 569 
 570         return 0;
 571 }
 572 
 573 /*
 574  * release an endpoint's urbs
 575  */
 576 static void release_urbs(struct snd_usb_endpoint *ep, int force)
 577 {
 578         int i;
 579 
 580         /* route incoming urbs to nirvana */
 581         ep->retire_data_urb = NULL;
 582         ep->prepare_data_urb = NULL;
 583 
 584         /* stop urbs */
 585         deactivate_urbs(ep, force);
 586         wait_clear_urbs(ep);
 587 
 588         for (i = 0; i < ep->nurbs; i++)
 589                 release_urb_ctx(&ep->urb[i]);
 590 
 591         if (ep->syncbuf)
 592                 usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
 593                                   ep->syncbuf, ep->sync_dma);
 594 
 595         ep->syncbuf = NULL;
 596         ep->nurbs = 0;
 597 }
 598 
 599 /*
 600  * configure a data endpoint
 601  */
 602 static int data_ep_set_params(struct snd_usb_endpoint *ep,
 603                               snd_pcm_format_t pcm_format,
 604                               unsigned int channels,
 605                               unsigned int period_bytes,
 606                               unsigned int frames_per_period,
 607                               unsigned int periods_per_buffer,
 608                               struct audioformat *fmt,
 609                               struct snd_usb_endpoint *sync_ep)
 610 {
 611         unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
 612         unsigned int max_packs_per_period, urbs_per_period, urb_packs;
 613         unsigned int max_urbs, i;
 614         int frame_bits = snd_pcm_format_physical_width(pcm_format) * channels;
 615         int tx_length_quirk = (ep->chip->tx_length_quirk &&
 616                                usb_pipeout(ep->pipe));
 617 
 618         if (pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
 619                 /*
 620                  * When operating in DSD DOP mode, the size of a sample frame
 621                  * in hardware differs from the actual physical format width
 622                  * because we need to make room for the DOP markers.
 623                  */
 624                 frame_bits += channels << 3;
 625         }
 626 
 627         ep->datainterval = fmt->datainterval;
 628         ep->stride = frame_bits >> 3;
 629 
 630         switch (pcm_format) {
 631         case SNDRV_PCM_FORMAT_U8:
 632                 ep->silence_value = 0x80;
 633                 break;
 634         case SNDRV_PCM_FORMAT_DSD_U8:
 635         case SNDRV_PCM_FORMAT_DSD_U16_LE:
 636         case SNDRV_PCM_FORMAT_DSD_U32_LE:
 637         case SNDRV_PCM_FORMAT_DSD_U16_BE:
 638         case SNDRV_PCM_FORMAT_DSD_U32_BE:
 639                 ep->silence_value = 0x69;
 640                 break;
 641         default:
 642                 ep->silence_value = 0;
 643         }
 644 
 645         /* assume max. frequency is 50% higher than nominal */
 646         ep->freqmax = ep->freqn + (ep->freqn >> 1);
 647         /* Round up freqmax to nearest integer in order to calculate maximum
 648          * packet size, which must represent a whole number of frames.
 649          * This is accomplished by adding 0x0.ffff before converting the
 650          * Q16.16 format into integer.
 651          * In order to accurately calculate the maximum packet size when
 652          * the data interval is more than 1 (i.e. ep->datainterval > 0),
 653          * multiply by the data interval prior to rounding. For instance,
 654          * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
 655          * frames with a data interval of 1, but 11 (10.25) frames with a
 656          * data interval of 2.
 657          * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
 658          * maximum datainterval value of 3, at USB full speed, higher for
 659          * USB high speed, noting that ep->freqmax is in units of
 660          * frames per packet in Q16.16 format.)
 661          */
 662         maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
 663                          (frame_bits >> 3);
 664         if (tx_length_quirk)
 665                 maxsize += sizeof(__le32); /* Space for length descriptor */
 666         /* but wMaxPacketSize might reduce this */
 667         if (ep->maxpacksize && ep->maxpacksize < maxsize) {
 668                 /* whatever fits into a max. size packet */
 669                 unsigned int data_maxsize = maxsize = ep->maxpacksize;
 670 
 671                 if (tx_length_quirk)
 672                         /* Need to remove the length descriptor to calc freq */
 673                         data_maxsize -= sizeof(__le32);
 674                 ep->freqmax = (data_maxsize / (frame_bits >> 3))
 675                                 << (16 - ep->datainterval);
 676         }
 677 
 678         if (ep->fill_max)
 679                 ep->curpacksize = ep->maxpacksize;
 680         else
 681                 ep->curpacksize = maxsize;
 682 
 683         if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL) {
 684                 packs_per_ms = 8 >> ep->datainterval;
 685                 max_packs_per_urb = MAX_PACKS_HS;
 686         } else {
 687                 packs_per_ms = 1;
 688                 max_packs_per_urb = MAX_PACKS;
 689         }
 690         if (sync_ep && !snd_usb_endpoint_implicit_feedback_sink(ep))
 691                 max_packs_per_urb = min(max_packs_per_urb,
 692                                         1U << sync_ep->syncinterval);
 693         max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
 694 
 695         /*
 696          * Capture endpoints need to use small URBs because there's no way
 697          * to tell in advance where the next period will end, and we don't
 698          * want the next URB to complete much after the period ends.
 699          *
 700          * Playback endpoints with implicit sync much use the same parameters
 701          * as their corresponding capture endpoint.
 702          */
 703         if (usb_pipein(ep->pipe) ||
 704                         snd_usb_endpoint_implicit_feedback_sink(ep)) {
 705 
 706                 urb_packs = packs_per_ms;
 707                 /*
 708                  * Wireless devices can poll at a max rate of once per 4ms.
 709                  * For dataintervals less than 5, increase the packet count to
 710                  * allow the host controller to use bursting to fill in the
 711                  * gaps.
 712                  */
 713                 if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_WIRELESS) {
 714                         int interval = ep->datainterval;
 715                         while (interval < 5) {
 716                                 urb_packs <<= 1;
 717                                 ++interval;
 718                         }
 719                 }
 720                 /* make capture URBs <= 1 ms and smaller than a period */
 721                 urb_packs = min(max_packs_per_urb, urb_packs);
 722                 while (urb_packs > 1 && urb_packs * maxsize >= period_bytes)
 723                         urb_packs >>= 1;
 724                 ep->nurbs = MAX_URBS;
 725 
 726         /*
 727          * Playback endpoints without implicit sync are adjusted so that
 728          * a period fits as evenly as possible in the smallest number of
 729          * URBs.  The total number of URBs is adjusted to the size of the
 730          * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
 731          */
 732         } else {
 733                 /* determine how small a packet can be */
 734                 minsize = (ep->freqn >> (16 - ep->datainterval)) *
 735                                 (frame_bits >> 3);
 736                 /* with sync from device, assume it can be 12% lower */
 737                 if (sync_ep)
 738                         minsize -= minsize >> 3;
 739                 minsize = max(minsize, 1u);
 740 
 741                 /* how many packets will contain an entire ALSA period? */
 742                 max_packs_per_period = DIV_ROUND_UP(period_bytes, minsize);
 743 
 744                 /* how many URBs will contain a period? */
 745                 urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
 746                                 max_packs_per_urb);
 747                 /* how many packets are needed in each URB? */
 748                 urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
 749 
 750                 /* limit the number of frames in a single URB */
 751                 ep->max_urb_frames = DIV_ROUND_UP(frames_per_period,
 752                                         urbs_per_period);
 753 
 754                 /* try to use enough URBs to contain an entire ALSA buffer */
 755                 max_urbs = min((unsigned) MAX_URBS,
 756                                 MAX_QUEUE * packs_per_ms / urb_packs);
 757                 ep->nurbs = min(max_urbs, urbs_per_period * periods_per_buffer);
 758         }
 759 
 760         /* allocate and initialize data urbs */
 761         for (i = 0; i < ep->nurbs; i++) {
 762                 struct snd_urb_ctx *u = &ep->urb[i];
 763                 u->index = i;
 764                 u->ep = ep;
 765                 u->packets = urb_packs;
 766                 u->buffer_size = maxsize * u->packets;
 767 
 768                 if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
 769                         u->packets++; /* for transfer delimiter */
 770                 u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
 771                 if (!u->urb)
 772                         goto out_of_memory;
 773 
 774                 u->urb->transfer_buffer =
 775                         usb_alloc_coherent(ep->chip->dev, u->buffer_size,
 776                                            GFP_KERNEL, &u->urb->transfer_dma);
 777                 if (!u->urb->transfer_buffer)
 778                         goto out_of_memory;
 779                 u->urb->pipe = ep->pipe;
 780                 u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
 781                 u->urb->interval = 1 << ep->datainterval;
 782                 u->urb->context = u;
 783                 u->urb->complete = snd_complete_urb;
 784                 INIT_LIST_HEAD(&u->ready_list);
 785         }
 786 
 787         return 0;
 788 
 789 out_of_memory:
 790         release_urbs(ep, 0);
 791         return -ENOMEM;
 792 }
 793 
 794 /*
 795  * configure a sync endpoint
 796  */
 797 static int sync_ep_set_params(struct snd_usb_endpoint *ep)
 798 {
 799         int i;
 800 
 801         ep->syncbuf = usb_alloc_coherent(ep->chip->dev, SYNC_URBS * 4,
 802                                          GFP_KERNEL, &ep->sync_dma);
 803         if (!ep->syncbuf)
 804                 return -ENOMEM;
 805 
 806         for (i = 0; i < SYNC_URBS; i++) {
 807                 struct snd_urb_ctx *u = &ep->urb[i];
 808                 u->index = i;
 809                 u->ep = ep;
 810                 u->packets = 1;
 811                 u->urb = usb_alloc_urb(1, GFP_KERNEL);
 812                 if (!u->urb)
 813                         goto out_of_memory;
 814                 u->urb->transfer_buffer = ep->syncbuf + i * 4;
 815                 u->urb->transfer_dma = ep->sync_dma + i * 4;
 816                 u->urb->transfer_buffer_length = 4;
 817                 u->urb->pipe = ep->pipe;
 818                 u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
 819                 u->urb->number_of_packets = 1;
 820                 u->urb->interval = 1 << ep->syncinterval;
 821                 u->urb->context = u;
 822                 u->urb->complete = snd_complete_urb;
 823         }
 824 
 825         ep->nurbs = SYNC_URBS;
 826 
 827         return 0;
 828 
 829 out_of_memory:
 830         release_urbs(ep, 0);
 831         return -ENOMEM;
 832 }
 833 
 834 /**
 835  * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
 836  *
 837  * @ep: the snd_usb_endpoint to configure
 838  * @pcm_format: the audio fomat.
 839  * @channels: the number of audio channels.
 840  * @period_bytes: the number of bytes in one alsa period.
 841  * @period_frames: the number of frames in one alsa period.
 842  * @buffer_periods: the number of periods in one alsa buffer.
 843  * @rate: the frame rate.
 844  * @fmt: the USB audio format information
 845  * @sync_ep: the sync endpoint to use, if any
 846  *
 847  * Determine the number of URBs to be used on this endpoint.
 848  * An endpoint must be configured before it can be started.
 849  * An endpoint that is already running can not be reconfigured.
 850  */
 851 int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
 852                                 snd_pcm_format_t pcm_format,
 853                                 unsigned int channels,
 854                                 unsigned int period_bytes,
 855                                 unsigned int period_frames,
 856                                 unsigned int buffer_periods,
 857                                 unsigned int rate,
 858                                 struct audioformat *fmt,
 859                                 struct snd_usb_endpoint *sync_ep)
 860 {
 861         int err;
 862 
 863         if (ep->use_count != 0) {
 864                 usb_audio_warn(ep->chip,
 865                          "Unable to change format on ep #%x: already in use\n",
 866                          ep->ep_num);
 867                 return -EBUSY;
 868         }
 869 
 870         /* release old buffers, if any */
 871         release_urbs(ep, 0);
 872 
 873         ep->datainterval = fmt->datainterval;
 874         ep->maxpacksize = fmt->maxpacksize;
 875         ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
 876 
 877         if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL)
 878                 ep->freqn = get_usb_full_speed_rate(rate);
 879         else
 880                 ep->freqn = get_usb_high_speed_rate(rate);
 881 
 882         /* calculate the frequency in 16.16 format */
 883         ep->freqm = ep->freqn;
 884         ep->freqshift = INT_MIN;
 885 
 886         ep->phase = 0;
 887 
 888         switch (ep->type) {
 889         case  SND_USB_ENDPOINT_TYPE_DATA:
 890                 err = data_ep_set_params(ep, pcm_format, channels,
 891                                          period_bytes, period_frames,
 892                                          buffer_periods, fmt, sync_ep);
 893                 break;
 894         case  SND_USB_ENDPOINT_TYPE_SYNC:
 895                 err = sync_ep_set_params(ep);
 896                 break;
 897         default:
 898                 err = -EINVAL;
 899         }
 900 
 901         usb_audio_dbg(ep->chip,
 902                 "Setting params for ep #%x (type %d, %d urbs), ret=%d\n",
 903                 ep->ep_num, ep->type, ep->nurbs, err);
 904 
 905         return err;
 906 }
 907 
 908 /**
 909  * snd_usb_endpoint_start: start an snd_usb_endpoint
 910  *
 911  * @ep: the endpoint to start
 912  *
 913  * A call to this function will increment the use count of the endpoint.
 914  * In case it is not already running, the URBs for this endpoint will be
 915  * submitted. Otherwise, this function does nothing.
 916  *
 917  * Must be balanced to calls of snd_usb_endpoint_stop().
 918  *
 919  * Returns an error if the URB submission failed, 0 in all other cases.
 920  */
 921 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
 922 {
 923         int err;
 924         unsigned int i;
 925 
 926         if (atomic_read(&ep->chip->shutdown))
 927                 return -EBADFD;
 928 
 929         /* already running? */
 930         if (++ep->use_count != 1)
 931                 return 0;
 932 
 933         /* just to be sure */
 934         deactivate_urbs(ep, false);
 935 
 936         ep->active_mask = 0;
 937         ep->unlink_mask = 0;
 938         ep->phase = 0;
 939 
 940         snd_usb_endpoint_start_quirk(ep);
 941 
 942         /*
 943          * If this endpoint has a data endpoint as implicit feedback source,
 944          * don't start the urbs here. Instead, mark them all as available,
 945          * wait for the record urbs to return and queue the playback urbs
 946          * from that context.
 947          */
 948 
 949         set_bit(EP_FLAG_RUNNING, &ep->flags);
 950 
 951         if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
 952                 for (i = 0; i < ep->nurbs; i++) {
 953                         struct snd_urb_ctx *ctx = ep->urb + i;
 954                         list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
 955                 }
 956 
 957                 return 0;
 958         }
 959 
 960         for (i = 0; i < ep->nurbs; i++) {
 961                 struct urb *urb = ep->urb[i].urb;
 962 
 963                 if (snd_BUG_ON(!urb))
 964                         goto __error;
 965 
 966                 if (usb_pipeout(ep->pipe)) {
 967                         prepare_outbound_urb(ep, urb->context);
 968                 } else {
 969                         prepare_inbound_urb(ep, urb->context);
 970                 }
 971 
 972                 err = usb_submit_urb(urb, GFP_ATOMIC);
 973                 if (err < 0) {
 974                         usb_audio_err(ep->chip,
 975                                 "cannot submit urb %d, error %d: %s\n",
 976                                 i, err, usb_error_string(err));
 977                         goto __error;
 978                 }
 979                 set_bit(i, &ep->active_mask);
 980         }
 981 
 982         return 0;
 983 
 984 __error:
 985         clear_bit(EP_FLAG_RUNNING, &ep->flags);
 986         ep->use_count--;
 987         deactivate_urbs(ep, false);
 988         return -EPIPE;
 989 }
 990 
 991 /**
 992  * snd_usb_endpoint_stop: stop an snd_usb_endpoint
 993  *
 994  * @ep: the endpoint to stop (may be NULL)
 995  *
 996  * A call to this function will decrement the use count of the endpoint.
 997  * In case the last user has requested the endpoint stop, the URBs will
 998  * actually be deactivated.
 999  *
1000  * Must be balanced to calls of snd_usb_endpoint_start().
1001  *
1002  * The caller needs to synchronize the pending stop operation via
1003  * snd_usb_endpoint_sync_pending_stop().
1004  */
1005 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep)
1006 {
1007         if (!ep)
1008                 return;
1009 
1010         if (snd_BUG_ON(ep->use_count == 0))
1011                 return;
1012 
1013         if (--ep->use_count == 0) {
1014                 deactivate_urbs(ep, false);
1015                 set_bit(EP_FLAG_STOPPING, &ep->flags);
1016         }
1017 }
1018 
1019 /**
1020  * snd_usb_endpoint_deactivate: deactivate an snd_usb_endpoint
1021  *
1022  * @ep: the endpoint to deactivate
1023  *
1024  * If the endpoint is not currently in use, this functions will
1025  * deactivate its associated URBs.
1026  *
1027  * In case of any active users, this functions does nothing.
1028  */
1029 void snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep)
1030 {
1031         if (!ep)
1032                 return;
1033 
1034         if (ep->use_count != 0)
1035                 return;
1036 
1037         deactivate_urbs(ep, true);
1038         wait_clear_urbs(ep);
1039 }
1040 
1041 /**
1042  * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1043  *
1044  * @ep: the endpoint to release
1045  *
1046  * This function does not care for the endpoint's use count but will tear
1047  * down all the streaming URBs immediately.
1048  */
1049 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1050 {
1051         release_urbs(ep, 1);
1052 }
1053 
1054 /**
1055  * snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint
1056  *
1057  * @ep: the endpoint to free
1058  *
1059  * This free all resources of the given ep.
1060  */
1061 void snd_usb_endpoint_free(struct snd_usb_endpoint *ep)
1062 {
1063         kfree(ep);
1064 }
1065 
1066 /**
1067  * snd_usb_handle_sync_urb: parse an USB sync packet
1068  *
1069  * @ep: the endpoint to handle the packet
1070  * @sender: the sending endpoint
1071  * @urb: the received packet
1072  *
1073  * This function is called from the context of an endpoint that received
1074  * the packet and is used to let another endpoint object handle the payload.
1075  */
1076 void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1077                              struct snd_usb_endpoint *sender,
1078                              const struct urb *urb)
1079 {
1080         int shift;
1081         unsigned int f;
1082         unsigned long flags;
1083 
1084         snd_BUG_ON(ep == sender);
1085 
1086         /*
1087          * In case the endpoint is operating in implicit feedback mode, prepare
1088          * a new outbound URB that has the same layout as the received packet
1089          * and add it to the list of pending urbs. queue_pending_output_urbs()
1090          * will take care of them later.
1091          */
1092         if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1093             ep->use_count != 0) {
1094 
1095                 /* implicit feedback case */
1096                 int i, bytes = 0;
1097                 struct snd_urb_ctx *in_ctx;
1098                 struct snd_usb_packet_info *out_packet;
1099 
1100                 in_ctx = urb->context;
1101 
1102                 /* Count overall packet size */
1103                 for (i = 0; i < in_ctx->packets; i++)
1104                         if (urb->iso_frame_desc[i].status == 0)
1105                                 bytes += urb->iso_frame_desc[i].actual_length;
1106 
1107                 /*
1108                  * skip empty packets. At least M-Audio's Fast Track Ultra stops
1109                  * streaming once it received a 0-byte OUT URB
1110                  */
1111                 if (bytes == 0)
1112                         return;
1113 
1114                 spin_lock_irqsave(&ep->lock, flags);
1115                 out_packet = ep->next_packet + ep->next_packet_write_pos;
1116 
1117                 /*
1118                  * Iterate through the inbound packet and prepare the lengths
1119                  * for the output packet. The OUT packet we are about to send
1120                  * will have the same amount of payload bytes per stride as the
1121                  * IN packet we just received. Since the actual size is scaled
1122                  * by the stride, use the sender stride to calculate the length
1123                  * in case the number of channels differ between the implicitly
1124                  * fed-back endpoint and the synchronizing endpoint.
1125                  */
1126 
1127                 out_packet->packets = in_ctx->packets;
1128                 for (i = 0; i < in_ctx->packets; i++) {
1129                         if (urb->iso_frame_desc[i].status == 0)
1130                                 out_packet->packet_size[i] =
1131                                         urb->iso_frame_desc[i].actual_length / sender->stride;
1132                         else
1133                                 out_packet->packet_size[i] = 0;
1134                 }
1135 
1136                 ep->next_packet_write_pos++;
1137                 ep->next_packet_write_pos %= MAX_URBS;
1138                 spin_unlock_irqrestore(&ep->lock, flags);
1139                 queue_pending_output_urbs(ep);
1140 
1141                 return;
1142         }
1143 
1144         /*
1145          * process after playback sync complete
1146          *
1147          * Full speed devices report feedback values in 10.14 format as samples
1148          * per frame, high speed devices in 16.16 format as samples per
1149          * microframe.
1150          *
1151          * Because the Audio Class 1 spec was written before USB 2.0, many high
1152          * speed devices use a wrong interpretation, some others use an
1153          * entirely different format.
1154          *
1155          * Therefore, we cannot predict what format any particular device uses
1156          * and must detect it automatically.
1157          */
1158 
1159         if (urb->iso_frame_desc[0].status != 0 ||
1160             urb->iso_frame_desc[0].actual_length < 3)
1161                 return;
1162 
1163         f = le32_to_cpup(urb->transfer_buffer);
1164         if (urb->iso_frame_desc[0].actual_length == 3)
1165                 f &= 0x00ffffff;
1166         else
1167                 f &= 0x0fffffff;
1168 
1169         if (f == 0)
1170                 return;
1171 
1172         if (unlikely(sender->tenor_fb_quirk)) {
1173                 /*
1174                  * Devices based on Tenor 8802 chipsets (TEAC UD-H01
1175                  * and others) sometimes change the feedback value
1176                  * by +/- 0x1.0000.
1177                  */
1178                 if (f < ep->freqn - 0x8000)
1179                         f += 0xf000;
1180                 else if (f > ep->freqn + 0x8000)
1181                         f -= 0xf000;
1182         } else if (unlikely(ep->freqshift == INT_MIN)) {
1183                 /*
1184                  * The first time we see a feedback value, determine its format
1185                  * by shifting it left or right until it matches the nominal
1186                  * frequency value.  This assumes that the feedback does not
1187                  * differ from the nominal value more than +50% or -25%.
1188                  */
1189                 shift = 0;
1190                 while (f < ep->freqn - ep->freqn / 4) {
1191                         f <<= 1;
1192                         shift++;
1193                 }
1194                 while (f > ep->freqn + ep->freqn / 2) {
1195                         f >>= 1;
1196                         shift--;
1197                 }
1198                 ep->freqshift = shift;
1199         } else if (ep->freqshift >= 0)
1200                 f <<= ep->freqshift;
1201         else
1202                 f >>= -ep->freqshift;
1203 
1204         if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1205                 /*
1206                  * If the frequency looks valid, set it.
1207                  * This value is referred to in prepare_playback_urb().
1208                  */
1209                 spin_lock_irqsave(&ep->lock, flags);
1210                 ep->freqm = f;
1211                 spin_unlock_irqrestore(&ep->lock, flags);
1212         } else {
1213                 /*
1214                  * Out of range; maybe the shift value is wrong.
1215                  * Reset it so that we autodetect again the next time.
1216                  */
1217                 ep->freqshift = INT_MIN;
1218         }
1219 }
1220
/* [<][>][^][v][top][bottom][index][help] */
root/sound/usb/endpoint.c

DEFINITIONS
