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 slave_next_packet_size() to 128 * determine the number of samples to be sent in the next packet. 129 * 130 * For implicit feedback, slave_next_packet_size() is unused. 131 */ 132 int snd_usb_endpoint_slave_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 /* 150 * For adaptive and synchronous endpoints, prepare_outbound_urb_sizes() 151 * will call next_packet_size() to determine the number of samples to be 152 * sent in the next packet. 153 */ 154 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep) 155 { 156 int ret; 157 158 if (ep->fill_max) 159 return ep->maxframesize; 160 161 ep->sample_accum += ep->sample_rem; 162 if (ep->sample_accum >= ep->pps) { 163 ep->sample_accum -= ep->pps; 164 ret = ep->packsize[1]; 165 } else { 166 ret = ep->packsize[0]; 167 } 168 169 return ret; 170 } 171 172 static void retire_outbound_urb(struct snd_usb_endpoint *ep, 173 struct snd_urb_ctx *urb_ctx) 174 { 175 if (ep->retire_data_urb) 176 ep->retire_data_urb(ep->data_subs, urb_ctx->urb); 177 } 178 179 static void retire_inbound_urb(struct snd_usb_endpoint *ep, 180 struct snd_urb_ctx *urb_ctx) 181 { 182 struct urb *urb = urb_ctx->urb; 183 184 if (unlikely(ep->skip_packets > 0)) { 185 ep->skip_packets--; 186 return; 187 } 188 189 if (ep->sync_slave) 190 snd_usb_handle_sync_urb(ep->sync_slave, ep, urb); 191 192 if (ep->retire_data_urb) 193 ep->retire_data_urb(ep->data_subs, urb); 194 } 195 196 static void prepare_silent_urb(struct snd_usb_endpoint *ep, 197 struct snd_urb_ctx *ctx) 198 { 199 struct urb *urb = ctx->urb; 200 unsigned int offs = 0; 201 unsigned int extra = 0; 202 __le32 packet_length; 203 int i; 204 205 /* For tx_length_quirk, put packet length at start of packet */ 206 if (ep->chip->tx_length_quirk) 207 extra = sizeof(packet_length); 208 209 for (i = 0; i < ctx->packets; ++i) { 210 unsigned int offset; 211 unsigned int length; 212 int counts; 213 214 if (ctx->packet_size[i]) 215 counts = ctx->packet_size[i]; 216 else if (ep->sync_master) 217 counts = snd_usb_endpoint_slave_next_packet_size(ep); 218 else 219 counts = snd_usb_endpoint_next_packet_size(ep); 220 221 length = counts * ep->stride; /* number of silent bytes */ 222 offset = offs * ep->stride + extra * i; 223 urb->iso_frame_desc[i].offset = offset; 224 urb->iso_frame_desc[i].length = length + extra; 225 if (extra) { 226 packet_length = cpu_to_le32(length); 227 memcpy(urb->transfer_buffer + offset, 228 &packet_length, sizeof(packet_length)); 229 } 230 memset(urb->transfer_buffer + offset + extra, 231 ep->silence_value, length); 232 offs += counts; 233 } 234 235 urb->number_of_packets = ctx->packets; 236 urb->transfer_buffer_length = offs * ep->stride + ctx->packets * extra; 237 } 238 239 /* 240 * Prepare a PLAYBACK urb for submission to the bus. 241 */ 242 static void prepare_outbound_urb(struct snd_usb_endpoint *ep, 243 struct snd_urb_ctx *ctx) 244 { 245 struct urb *urb = ctx->urb; 246 unsigned char *cp = urb->transfer_buffer; 247 248 urb->dev = ep->chip->dev; /* we need to set this at each time */ 249 250 switch (ep->type) { 251 case SND_USB_ENDPOINT_TYPE_DATA: 252 if (ep->prepare_data_urb) { 253 ep->prepare_data_urb(ep->data_subs, urb); 254 } else { 255 /* no data provider, so send silence */ 256 prepare_silent_urb(ep, ctx); 257 } 258 break; 259 260 case SND_USB_ENDPOINT_TYPE_SYNC: 261 if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) { 262 /* 263 * fill the length and offset of each urb descriptor. 264 * the fixed 12.13 frequency is passed as 16.16 through the pipe. 265 */ 266 urb->iso_frame_desc[0].length = 4; 267 urb->iso_frame_desc[0].offset = 0; 268 cp[0] = ep->freqn; 269 cp[1] = ep->freqn >> 8; 270 cp[2] = ep->freqn >> 16; 271 cp[3] = ep->freqn >> 24; 272 } else { 273 /* 274 * fill the length and offset of each urb descriptor. 275 * the fixed 10.14 frequency is passed through the pipe. 276 */ 277 urb->iso_frame_desc[0].length = 3; 278 urb->iso_frame_desc[0].offset = 0; 279 cp[0] = ep->freqn >> 2; 280 cp[1] = ep->freqn >> 10; 281 cp[2] = ep->freqn >> 18; 282 } 283 284 break; 285 } 286 } 287 288 /* 289 * Prepare a CAPTURE or SYNC urb for submission to the bus. 290 */ 291 static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep, 292 struct snd_urb_ctx *urb_ctx) 293 { 294 int i, offs; 295 struct urb *urb = urb_ctx->urb; 296 297 urb->dev = ep->chip->dev; /* we need to set this at each time */ 298 299 switch (ep->type) { 300 case SND_USB_ENDPOINT_TYPE_DATA: 301 offs = 0; 302 for (i = 0; i < urb_ctx->packets; i++) { 303 urb->iso_frame_desc[i].offset = offs; 304 urb->iso_frame_desc[i].length = ep->curpacksize; 305 offs += ep->curpacksize; 306 } 307 308 urb->transfer_buffer_length = offs; 309 urb->number_of_packets = urb_ctx->packets; 310 break; 311 312 case SND_USB_ENDPOINT_TYPE_SYNC: 313 urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize); 314 urb->iso_frame_desc[0].offset = 0; 315 break; 316 } 317 } 318 319 /* 320 * Send output urbs that have been prepared previously. URBs are dequeued 321 * from ep->ready_playback_urbs and in case there there aren't any available 322 * or there are no packets that have been prepared, this function does 323 * nothing. 324 * 325 * The reason why the functionality of sending and preparing URBs is separated 326 * is that host controllers don't guarantee the order in which they return 327 * inbound and outbound packets to their submitters. 328 * 329 * This function is only used for implicit feedback endpoints. For endpoints 330 * driven by dedicated sync endpoints, URBs are immediately re-submitted 331 * from their completion handler. 332 */ 333 static void queue_pending_output_urbs(struct snd_usb_endpoint *ep) 334 { 335 while (test_bit(EP_FLAG_RUNNING, &ep->flags)) { 336 337 unsigned long flags; 338 struct snd_usb_packet_info *uninitialized_var(packet); 339 struct snd_urb_ctx *ctx = NULL; 340 int err, i; 341 342 spin_lock_irqsave(&ep->lock, flags); 343 if (ep->next_packet_read_pos != ep->next_packet_write_pos) { 344 packet = ep->next_packet + ep->next_packet_read_pos; 345 ep->next_packet_read_pos++; 346 ep->next_packet_read_pos %= MAX_URBS; 347 348 /* take URB out of FIFO */ 349 if (!list_empty(&ep->ready_playback_urbs)) { 350 ctx = list_first_entry(&ep->ready_playback_urbs, 351 struct snd_urb_ctx, ready_list); 352 list_del_init(&ctx->ready_list); 353 } 354 } 355 spin_unlock_irqrestore(&ep->lock, flags); 356 357 if (ctx == NULL) 358 return; 359 360 /* copy over the length information */ 361 for (i = 0; i < packet->packets; i++) 362 ctx->packet_size[i] = packet->packet_size[i]; 363 364 /* call the data handler to fill in playback data */ 365 prepare_outbound_urb(ep, ctx); 366 367 err = usb_submit_urb(ctx->urb, GFP_ATOMIC); 368 if (err < 0) 369 usb_audio_err(ep->chip, 370 "Unable to submit urb #%d: %d (urb %p)\n", 371 ctx->index, err, ctx->urb); 372 else 373 set_bit(ctx->index, &ep->active_mask); 374 } 375 } 376 377 /* 378 * complete callback for urbs 379 */ 380 static void snd_complete_urb(struct urb *urb) 381 { 382 struct snd_urb_ctx *ctx = urb->context; 383 struct snd_usb_endpoint *ep = ctx->ep; 384 struct snd_pcm_substream *substream; 385 unsigned long flags; 386 int err; 387 388 if (unlikely(urb->status == -ENOENT || /* unlinked */ 389 urb->status == -ENODEV || /* device removed */ 390 urb->status == -ECONNRESET || /* unlinked */ 391 urb->status == -ESHUTDOWN)) /* device disabled */ 392 goto exit_clear; 393 /* device disconnected */ 394 if (unlikely(atomic_read(&ep->chip->shutdown))) 395 goto exit_clear; 396 397 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags))) 398 goto exit_clear; 399 400 if (usb_pipeout(ep->pipe)) { 401 retire_outbound_urb(ep, ctx); 402 /* can be stopped during retire callback */ 403 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags))) 404 goto exit_clear; 405 406 if (snd_usb_endpoint_implicit_feedback_sink(ep)) { 407 spin_lock_irqsave(&ep->lock, flags); 408 list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs); 409 spin_unlock_irqrestore(&ep->lock, flags); 410 queue_pending_output_urbs(ep); 411 412 goto exit_clear; 413 } 414 415 prepare_outbound_urb(ep, ctx); 416 /* can be stopped during prepare callback */ 417 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags))) 418 goto exit_clear; 419 } else { 420 retire_inbound_urb(ep, ctx); 421 /* can be stopped during retire callback */ 422 if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags))) 423 goto exit_clear; 424 425 prepare_inbound_urb(ep, ctx); 426 } 427 428 err = usb_submit_urb(urb, GFP_ATOMIC); 429 if (err == 0) 430 return; 431 432 usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err); 433 if (ep->data_subs && ep->data_subs->pcm_substream) { 434 substream = ep->data_subs->pcm_substream; 435 snd_pcm_stop_xrun(substream); 436 } 437 438 exit_clear: 439 clear_bit(ctx->index, &ep->active_mask); 440 } 441 442 /** 443 * snd_usb_add_endpoint: Add an endpoint to an USB audio chip 444 * 445 * @chip: The chip 446 * @alts: The USB host interface 447 * @ep_num: The number of the endpoint to use 448 * @direction: SNDRV_PCM_STREAM_PLAYBACK or SNDRV_PCM_STREAM_CAPTURE 449 * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC 450 * 451 * If the requested endpoint has not been added to the given chip before, 452 * a new instance is created. Otherwise, a pointer to the previoulsy 453 * created instance is returned. In case of any error, NULL is returned. 454 * 455 * New endpoints will be added to chip->ep_list and must be freed by 456 * calling snd_usb_endpoint_free(). 457 * 458 * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that 459 * bNumEndpoints > 1 beforehand. 460 */ 461 struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip, 462 struct usb_host_interface *alts, 463 int ep_num, int direction, int type) 464 { 465 struct snd_usb_endpoint *ep; 466 int is_playback = direction == SNDRV_PCM_STREAM_PLAYBACK; 467 468 if (WARN_ON(!alts)) 469 return NULL; 470 471 mutex_lock(&chip->mutex); 472 473 list_for_each_entry(ep, &chip->ep_list, list) { 474 if (ep->ep_num == ep_num && 475 ep->iface == alts->desc.bInterfaceNumber && 476 ep->altsetting == alts->desc.bAlternateSetting) { 477 usb_audio_dbg(ep->chip, 478 "Re-using EP %x in iface %d,%d @%p\n", 479 ep_num, ep->iface, ep->altsetting, ep); 480 goto __exit_unlock; 481 } 482 } 483 484 usb_audio_dbg(chip, "Creating new %s %s endpoint #%x\n", 485 is_playback ? "playback" : "capture", 486 type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync", 487 ep_num); 488 489 ep = kzalloc(sizeof(*ep), GFP_KERNEL); 490 if (!ep) 491 goto __exit_unlock; 492 493 ep->chip = chip; 494 spin_lock_init(&ep->lock); 495 ep->type = type; 496 ep->ep_num = ep_num; 497 ep->iface = alts->desc.bInterfaceNumber; 498 ep->altsetting = alts->desc.bAlternateSetting; 499 INIT_LIST_HEAD(&ep->ready_playback_urbs); 500 ep_num &= USB_ENDPOINT_NUMBER_MASK; 501 502 if (is_playback) 503 ep->pipe = usb_sndisocpipe(chip->dev, ep_num); 504 else 505 ep->pipe = usb_rcvisocpipe(chip->dev, ep_num); 506 507 if (type == SND_USB_ENDPOINT_TYPE_SYNC) { 508 if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE && 509 get_endpoint(alts, 1)->bRefresh >= 1 && 510 get_endpoint(alts, 1)->bRefresh <= 9) 511 ep->syncinterval = get_endpoint(alts, 1)->bRefresh; 512 else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) 513 ep->syncinterval = 1; 514 else if (get_endpoint(alts, 1)->bInterval >= 1 && 515 get_endpoint(alts, 1)->bInterval <= 16) 516 ep->syncinterval = get_endpoint(alts, 1)->bInterval - 1; 517 else 518 ep->syncinterval = 3; 519 520 ep->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize); 521 } 522 523 list_add_tail(&ep->list, &chip->ep_list); 524 525 ep->is_implicit_feedback = 0; 526 527 __exit_unlock: 528 mutex_unlock(&chip->mutex); 529 530 return ep; 531 } 532 533 /* 534 * wait until all urbs are processed. 535 */ 536 static int wait_clear_urbs(struct snd_usb_endpoint *ep) 537 { 538 unsigned long end_time = jiffies + msecs_to_jiffies(1000); 539 int alive; 540 541 do { 542 alive = bitmap_weight(&ep->active_mask, ep->nurbs); 543 if (!alive) 544 break; 545 546 schedule_timeout_uninterruptible(1); 547 } while (time_before(jiffies, end_time)); 548 549 if (alive) 550 usb_audio_err(ep->chip, 551 "timeout: still %d active urbs on EP #%x\n", 552 alive, ep->ep_num); 553 clear_bit(EP_FLAG_STOPPING, &ep->flags); 554 555 ep->data_subs = NULL; 556 ep->sync_slave = NULL; 557 ep->retire_data_urb = NULL; 558 ep->prepare_data_urb = NULL; 559 560 return 0; 561 } 562 563 /* sync the pending stop operation; 564 * this function itself doesn't trigger the stop operation 565 */ 566 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep) 567 { 568 if (ep && test_bit(EP_FLAG_STOPPING, &ep->flags)) 569 wait_clear_urbs(ep); 570 } 571 572 /* 573 * unlink active urbs. 574 */ 575 static int deactivate_urbs(struct snd_usb_endpoint *ep, bool force) 576 { 577 unsigned int i; 578 579 if (!force && atomic_read(&ep->chip->shutdown)) /* to be sure... */ 580 return -EBADFD; 581 582 clear_bit(EP_FLAG_RUNNING, &ep->flags); 583 584 INIT_LIST_HEAD(&ep->ready_playback_urbs); 585 ep->next_packet_read_pos = 0; 586 ep->next_packet_write_pos = 0; 587 588 for (i = 0; i < ep->nurbs; i++) { 589 if (test_bit(i, &ep->active_mask)) { 590 if (!test_and_set_bit(i, &ep->unlink_mask)) { 591 struct urb *u = ep->urb[i].urb; 592 usb_unlink_urb(u); 593 } 594 } 595 } 596 597 return 0; 598 } 599 600 /* 601 * release an endpoint's urbs 602 */ 603 static void release_urbs(struct snd_usb_endpoint *ep, int force) 604 { 605 int i; 606 607 /* route incoming urbs to nirvana */ 608 ep->retire_data_urb = NULL; 609 ep->prepare_data_urb = NULL; 610 611 /* stop urbs */ 612 deactivate_urbs(ep, force); 613 wait_clear_urbs(ep); 614 615 for (i = 0; i < ep->nurbs; i++) 616 release_urb_ctx(&ep->urb[i]); 617 618 if (ep->syncbuf) 619 usb_free_coherent(ep->chip->dev, SYNC_URBS * 4, 620 ep->syncbuf, ep->sync_dma); 621 622 ep->syncbuf = NULL; 623 ep->nurbs = 0; 624 } 625 626 /* 627 * Check data endpoint for format differences 628 */ 629 static bool check_ep_params(struct snd_usb_endpoint *ep, 630 snd_pcm_format_t pcm_format, 631 unsigned int channels, 632 unsigned int period_bytes, 633 unsigned int frames_per_period, 634 unsigned int periods_per_buffer, 635 struct audioformat *fmt, 636 struct snd_usb_endpoint *sync_ep) 637 { 638 unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb; 639 unsigned int max_packs_per_period, urbs_per_period, urb_packs; 640 unsigned int max_urbs; 641 int frame_bits = snd_pcm_format_physical_width(pcm_format) * channels; 642 int tx_length_quirk = (ep->chip->tx_length_quirk && 643 usb_pipeout(ep->pipe)); 644 bool ret = 1; 645 646 if (pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) { 647 /* 648 * When operating in DSD DOP mode, the size of a sample frame 649 * in hardware differs from the actual physical format width 650 * because we need to make room for the DOP markers. 651 */ 652 frame_bits += channels << 3; 653 } 654 655 ret = ret && (ep->datainterval == fmt->datainterval); 656 ret = ret && (ep->stride == frame_bits >> 3); 657 658 switch (pcm_format) { 659 case SNDRV_PCM_FORMAT_U8: 660 ret = ret && (ep->silence_value == 0x80); 661 break; 662 case SNDRV_PCM_FORMAT_DSD_U8: 663 case SNDRV_PCM_FORMAT_DSD_U16_LE: 664 case SNDRV_PCM_FORMAT_DSD_U32_LE: 665 case SNDRV_PCM_FORMAT_DSD_U16_BE: 666 case SNDRV_PCM_FORMAT_DSD_U32_BE: 667 ret = ret && (ep->silence_value == 0x69); 668 break; 669 default: 670 ret = ret && (ep->silence_value == 0); 671 } 672 673 /* assume max. frequency is 50% higher than nominal */ 674 ret = ret && (ep->freqmax == ep->freqn + (ep->freqn >> 1)); 675 /* Round up freqmax to nearest integer in order to calculate maximum 676 * packet size, which must represent a whole number of frames. 677 * This is accomplished by adding 0x0.ffff before converting the 678 * Q16.16 format into integer. 679 * In order to accurately calculate the maximum packet size when 680 * the data interval is more than 1 (i.e. ep->datainterval > 0), 681 * multiply by the data interval prior to rounding. For instance, 682 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125) 683 * frames with a data interval of 1, but 11 (10.25) frames with a 684 * data interval of 2. 685 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the 686 * maximum datainterval value of 3, at USB full speed, higher for 687 * USB high speed, noting that ep->freqmax is in units of 688 * frames per packet in Q16.16 format.) 689 */ 690 maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) * 691 (frame_bits >> 3); 692 if (tx_length_quirk) 693 maxsize += sizeof(__le32); /* Space for length descriptor */ 694 /* but wMaxPacketSize might reduce this */ 695 if (ep->maxpacksize && ep->maxpacksize < maxsize) { 696 /* whatever fits into a max. size packet */ 697 unsigned int data_maxsize = maxsize = ep->maxpacksize; 698 699 if (tx_length_quirk) 700 /* Need to remove the length descriptor to calc freq */ 701 data_maxsize -= sizeof(__le32); 702 ret = ret && (ep->freqmax == (data_maxsize / (frame_bits >> 3)) 703 << (16 - ep->datainterval)); 704 } 705 706 if (ep->fill_max) 707 ret = ret && (ep->curpacksize == ep->maxpacksize); 708 else 709 ret = ret && (ep->curpacksize == maxsize); 710 711 if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL) { 712 packs_per_ms = 8 >> ep->datainterval; 713 max_packs_per_urb = MAX_PACKS_HS; 714 } else { 715 packs_per_ms = 1; 716 max_packs_per_urb = MAX_PACKS; 717 } 718 if (sync_ep && !snd_usb_endpoint_implicit_feedback_sink(ep)) 719 max_packs_per_urb = min(max_packs_per_urb, 720 1U << sync_ep->syncinterval); 721 max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval); 722 723 /* 724 * Capture endpoints need to use small URBs because there's no way 725 * to tell in advance where the next period will end, and we don't 726 * want the next URB to complete much after the period ends. 727 * 728 * Playback endpoints with implicit sync much use the same parameters 729 * as their corresponding capture endpoint. 730 */ 731 if (usb_pipein(ep->pipe) || 732 snd_usb_endpoint_implicit_feedback_sink(ep)) { 733 734 urb_packs = packs_per_ms; 735 /* 736 * Wireless devices can poll at a max rate of once per 4ms. 737 * For dataintervals less than 5, increase the packet count to 738 * allow the host controller to use bursting to fill in the 739 * gaps. 740 */ 741 if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_WIRELESS) { 742 int interval = ep->datainterval; 743 744 while (interval < 5) { 745 urb_packs <<= 1; 746 ++interval; 747 } 748 } 749 /* make capture URBs <= 1 ms and smaller than a period */ 750 urb_packs = min(max_packs_per_urb, urb_packs); 751 while (urb_packs > 1 && urb_packs * maxsize >= period_bytes) 752 urb_packs >>= 1; 753 ret = ret && (ep->nurbs == MAX_URBS); 754 755 /* 756 * Playback endpoints without implicit sync are adjusted so that 757 * a period fits as evenly as possible in the smallest number of 758 * URBs. The total number of URBs is adjusted to the size of the 759 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits. 760 */ 761 } else { 762 /* determine how small a packet can be */ 763 minsize = (ep->freqn >> (16 - ep->datainterval)) * 764 (frame_bits >> 3); 765 /* with sync from device, assume it can be 12% lower */ 766 if (sync_ep) 767 minsize -= minsize >> 3; 768 minsize = max(minsize, 1u); 769 770 /* how many packets will contain an entire ALSA period? */ 771 max_packs_per_period = DIV_ROUND_UP(period_bytes, minsize); 772 773 /* how many URBs will contain a period? */ 774 urbs_per_period = DIV_ROUND_UP(max_packs_per_period, 775 max_packs_per_urb); 776 /* how many packets are needed in each URB? */ 777 urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period); 778 779 /* limit the number of frames in a single URB */ 780 ret = ret && (ep->max_urb_frames == 781 DIV_ROUND_UP(frames_per_period, urbs_per_period)); 782 783 /* try to use enough URBs to contain an entire ALSA buffer */ 784 max_urbs = min((unsigned) MAX_URBS, 785 MAX_QUEUE * packs_per_ms / urb_packs); 786 ret = ret && (ep->nurbs == min(max_urbs, 787 urbs_per_period * periods_per_buffer)); 788 } 789 790 ret = ret && (ep->datainterval == fmt->datainterval); 791 ret = ret && (ep->maxpacksize == fmt->maxpacksize); 792 ret = ret && 793 (ep->fill_max == !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX)); 794 795 return ret; 796 } 797 798 /* 799 * configure a data endpoint 800 */ 801 static int data_ep_set_params(struct snd_usb_endpoint *ep, 802 snd_pcm_format_t pcm_format, 803 unsigned int channels, 804 unsigned int period_bytes, 805 unsigned int frames_per_period, 806 unsigned int periods_per_buffer, 807 struct audioformat *fmt, 808 struct snd_usb_endpoint *sync_ep) 809 { 810 unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb; 811 unsigned int max_packs_per_period, urbs_per_period, urb_packs; 812 unsigned int max_urbs, i; 813 int frame_bits = snd_pcm_format_physical_width(pcm_format) * channels; 814 int tx_length_quirk = (ep->chip->tx_length_quirk && 815 usb_pipeout(ep->pipe)); 816 817 if (pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) { 818 /* 819 * When operating in DSD DOP mode, the size of a sample frame 820 * in hardware differs from the actual physical format width 821 * because we need to make room for the DOP markers. 822 */ 823 frame_bits += channels << 3; 824 } 825 826 ep->datainterval = fmt->datainterval; 827 ep->stride = frame_bits >> 3; 828 829 switch (pcm_format) { 830 case SNDRV_PCM_FORMAT_U8: 831 ep->silence_value = 0x80; 832 break; 833 case SNDRV_PCM_FORMAT_DSD_U8: 834 case SNDRV_PCM_FORMAT_DSD_U16_LE: 835 case SNDRV_PCM_FORMAT_DSD_U32_LE: 836 case SNDRV_PCM_FORMAT_DSD_U16_BE: 837 case SNDRV_PCM_FORMAT_DSD_U32_BE: 838 ep->silence_value = 0x69; 839 break; 840 default: 841 ep->silence_value = 0; 842 } 843 844 /* assume max. frequency is 50% higher than nominal */ 845 ep->freqmax = ep->freqn + (ep->freqn >> 1); 846 /* Round up freqmax to nearest integer in order to calculate maximum 847 * packet size, which must represent a whole number of frames. 848 * This is accomplished by adding 0x0.ffff before converting the 849 * Q16.16 format into integer. 850 * In order to accurately calculate the maximum packet size when 851 * the data interval is more than 1 (i.e. ep->datainterval > 0), 852 * multiply by the data interval prior to rounding. For instance, 853 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125) 854 * frames with a data interval of 1, but 11 (10.25) frames with a 855 * data interval of 2. 856 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the 857 * maximum datainterval value of 3, at USB full speed, higher for 858 * USB high speed, noting that ep->freqmax is in units of 859 * frames per packet in Q16.16 format.) 860 */ 861 maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) * 862 (frame_bits >> 3); 863 if (tx_length_quirk) 864 maxsize += sizeof(__le32); /* Space for length descriptor */ 865 /* but wMaxPacketSize might reduce this */ 866 if (ep->maxpacksize && ep->maxpacksize < maxsize) { 867 /* whatever fits into a max. size packet */ 868 unsigned int data_maxsize = maxsize = ep->maxpacksize; 869 870 if (tx_length_quirk) 871 /* Need to remove the length descriptor to calc freq */ 872 data_maxsize -= sizeof(__le32); 873 ep->freqmax = (data_maxsize / (frame_bits >> 3)) 874 << (16 - ep->datainterval); 875 } 876 877 if (ep->fill_max) 878 ep->curpacksize = ep->maxpacksize; 879 else 880 ep->curpacksize = maxsize; 881 882 if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL) { 883 packs_per_ms = 8 >> ep->datainterval; 884 max_packs_per_urb = MAX_PACKS_HS; 885 } else { 886 packs_per_ms = 1; 887 max_packs_per_urb = MAX_PACKS; 888 } 889 if (sync_ep && !snd_usb_endpoint_implicit_feedback_sink(ep)) 890 max_packs_per_urb = min(max_packs_per_urb, 891 1U << sync_ep->syncinterval); 892 max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval); 893 894 /* 895 * Capture endpoints need to use small URBs because there's no way 896 * to tell in advance where the next period will end, and we don't 897 * want the next URB to complete much after the period ends. 898 * 899 * Playback endpoints with implicit sync much use the same parameters 900 * as their corresponding capture endpoint. 901 */ 902 if (usb_pipein(ep->pipe) || 903 snd_usb_endpoint_implicit_feedback_sink(ep)) { 904 905 urb_packs = packs_per_ms; 906 /* 907 * Wireless devices can poll at a max rate of once per 4ms. 908 * For dataintervals less than 5, increase the packet count to 909 * allow the host controller to use bursting to fill in the 910 * gaps. 911 */ 912 if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_WIRELESS) { 913 int interval = ep->datainterval; 914 while (interval < 5) { 915 urb_packs <<= 1; 916 ++interval; 917 } 918 } 919 /* make capture URBs <= 1 ms and smaller than a period */ 920 urb_packs = min(max_packs_per_urb, urb_packs); 921 while (urb_packs > 1 && urb_packs * maxsize >= period_bytes) 922 urb_packs >>= 1; 923 ep->nurbs = MAX_URBS; 924 925 /* 926 * Playback endpoints without implicit sync are adjusted so that 927 * a period fits as evenly as possible in the smallest number of 928 * URBs. The total number of URBs is adjusted to the size of the 929 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits. 930 */ 931 } else { 932 /* determine how small a packet can be */ 933 minsize = (ep->freqn >> (16 - ep->datainterval)) * 934 (frame_bits >> 3); 935 /* with sync from device, assume it can be 12% lower */ 936 if (sync_ep) 937 minsize -= minsize >> 3; 938 minsize = max(minsize, 1u); 939 940 /* how many packets will contain an entire ALSA period? */ 941 max_packs_per_period = DIV_ROUND_UP(period_bytes, minsize); 942 943 /* how many URBs will contain a period? */ 944 urbs_per_period = DIV_ROUND_UP(max_packs_per_period, 945 max_packs_per_urb); 946 /* how many packets are needed in each URB? */ 947 urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period); 948 949 /* limit the number of frames in a single URB */ 950 ep->max_urb_frames = DIV_ROUND_UP(frames_per_period, 951 urbs_per_period); 952 953 /* try to use enough URBs to contain an entire ALSA buffer */ 954 max_urbs = min((unsigned) MAX_URBS, 955 MAX_QUEUE * packs_per_ms / urb_packs); 956 ep->nurbs = min(max_urbs, urbs_per_period * periods_per_buffer); 957 } 958 959 /* allocate and initialize data urbs */ 960 for (i = 0; i < ep->nurbs; i++) { 961 struct snd_urb_ctx *u = &ep->urb[i]; 962 u->index = i; 963 u->ep = ep; 964 u->packets = urb_packs; 965 u->buffer_size = maxsize * u->packets; 966 967 if (fmt->fmt_type == UAC_FORMAT_TYPE_II) 968 u->packets++; /* for transfer delimiter */ 969 u->urb = usb_alloc_urb(u->packets, GFP_KERNEL); 970 if (!u->urb) 971 goto out_of_memory; 972 973 u->urb->transfer_buffer = 974 usb_alloc_coherent(ep->chip->dev, u->buffer_size, 975 GFP_KERNEL, &u->urb->transfer_dma); 976 if (!u->urb->transfer_buffer) 977 goto out_of_memory; 978 u->urb->pipe = ep->pipe; 979 u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP; 980 u->urb->interval = 1 << ep->datainterval; 981 u->urb->context = u; 982 u->urb->complete = snd_complete_urb; 983 INIT_LIST_HEAD(&u->ready_list); 984 } 985 986 return 0; 987 988 out_of_memory: 989 release_urbs(ep, 0); 990 return -ENOMEM; 991 } 992 993 /* 994 * configure a sync endpoint 995 */ 996 static int sync_ep_set_params(struct snd_usb_endpoint *ep) 997 { 998 int i; 999 1000 ep->syncbuf = usb_alloc_coherent(ep->chip->dev, SYNC_URBS * 4, 1001 GFP_KERNEL, &ep->sync_dma); 1002 if (!ep->syncbuf) 1003 return -ENOMEM; 1004 1005 for (i = 0; i < SYNC_URBS; i++) { 1006 struct snd_urb_ctx *u = &ep->urb[i]; 1007 u->index = i; 1008 u->ep = ep; 1009 u->packets = 1; 1010 u->urb = usb_alloc_urb(1, GFP_KERNEL); 1011 if (!u->urb) 1012 goto out_of_memory; 1013 u->urb->transfer_buffer = ep->syncbuf + i * 4; 1014 u->urb->transfer_dma = ep->sync_dma + i * 4; 1015 u->urb->transfer_buffer_length = 4; 1016 u->urb->pipe = ep->pipe; 1017 u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP; 1018 u->urb->number_of_packets = 1; 1019 u->urb->interval = 1 << ep->syncinterval; 1020 u->urb->context = u; 1021 u->urb->complete = snd_complete_urb; 1022 } 1023 1024 ep->nurbs = SYNC_URBS; 1025 1026 return 0; 1027 1028 out_of_memory: 1029 release_urbs(ep, 0); 1030 return -ENOMEM; 1031 } 1032 1033 /** 1034 * snd_usb_endpoint_set_params: configure an snd_usb_endpoint 1035 * 1036 * @ep: the snd_usb_endpoint to configure 1037 * @pcm_format: the audio fomat. 1038 * @channels: the number of audio channels. 1039 * @period_bytes: the number of bytes in one alsa period. 1040 * @period_frames: the number of frames in one alsa period. 1041 * @buffer_periods: the number of periods in one alsa buffer. 1042 * @rate: the frame rate. 1043 * @fmt: the USB audio format information 1044 * @sync_ep: the sync endpoint to use, if any 1045 * 1046 * Determine the number of URBs to be used on this endpoint. 1047 * An endpoint must be configured before it can be started. 1048 * An endpoint that is already running can not be reconfigured. 1049 */ 1050 int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep, 1051 snd_pcm_format_t pcm_format, 1052 unsigned int channels, 1053 unsigned int period_bytes, 1054 unsigned int period_frames, 1055 unsigned int buffer_periods, 1056 unsigned int rate, 1057 struct audioformat *fmt, 1058 struct snd_usb_endpoint *sync_ep) 1059 { 1060 int err; 1061 1062 if (ep->use_count != 0) { 1063 bool check = ep->is_implicit_feedback && 1064 check_ep_params(ep, pcm_format, 1065 channels, period_bytes, 1066 period_frames, buffer_periods, 1067 fmt, sync_ep); 1068 1069 if (!check) { 1070 usb_audio_warn(ep->chip, 1071 "Unable to change format on ep #%x: already in use\n", 1072 ep->ep_num); 1073 return -EBUSY; 1074 } 1075 1076 usb_audio_dbg(ep->chip, 1077 "Ep #%x already in use as implicit feedback but format not changed\n", 1078 ep->ep_num); 1079 return 0; 1080 } 1081 1082 /* release old buffers, if any */ 1083 release_urbs(ep, 0); 1084 1085 ep->datainterval = fmt->datainterval; 1086 ep->maxpacksize = fmt->maxpacksize; 1087 ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX); 1088 1089 if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL) { 1090 ep->freqn = get_usb_full_speed_rate(rate); 1091 ep->pps = 1000 >> ep->datainterval; 1092 } else { 1093 ep->freqn = get_usb_high_speed_rate(rate); 1094 ep->pps = 8000 >> ep->datainterval; 1095 } 1096 1097 ep->sample_rem = rate % ep->pps; 1098 ep->packsize[0] = rate / ep->pps; 1099 ep->packsize[1] = (rate + (ep->pps - 1)) / ep->pps; 1100 1101 /* calculate the frequency in 16.16 format */ 1102 ep->freqm = ep->freqn; 1103 ep->freqshift = INT_MIN; 1104 1105 ep->phase = 0; 1106 1107 switch (ep->type) { 1108 case SND_USB_ENDPOINT_TYPE_DATA: 1109 err = data_ep_set_params(ep, pcm_format, channels, 1110 period_bytes, period_frames, 1111 buffer_periods, fmt, sync_ep); 1112 break; 1113 case SND_USB_ENDPOINT_TYPE_SYNC: 1114 err = sync_ep_set_params(ep); 1115 break; 1116 default: 1117 err = -EINVAL; 1118 } 1119 1120 usb_audio_dbg(ep->chip, 1121 "Setting params for ep #%x (type %d, %d urbs), ret=%d\n", 1122 ep->ep_num, ep->type, ep->nurbs, err); 1123 1124 return err; 1125 } 1126 1127 /** 1128 * snd_usb_endpoint_start: start an snd_usb_endpoint 1129 * 1130 * @ep: the endpoint to start 1131 * 1132 * A call to this function will increment the use count of the endpoint. 1133 * In case it is not already running, the URBs for this endpoint will be 1134 * submitted. Otherwise, this function does nothing. 1135 * 1136 * Must be balanced to calls of snd_usb_endpoint_stop(). 1137 * 1138 * Returns an error if the URB submission failed, 0 in all other cases. 1139 */ 1140 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep) 1141 { 1142 int err; 1143 unsigned int i; 1144 1145 if (atomic_read(&ep->chip->shutdown)) 1146 return -EBADFD; 1147 1148 /* already running? */ 1149 if (++ep->use_count != 1) 1150 return 0; 1151 1152 /* just to be sure */ 1153 deactivate_urbs(ep, false); 1154 1155 ep->active_mask = 0; 1156 ep->unlink_mask = 0; 1157 ep->phase = 0; 1158 ep->sample_accum = 0; 1159 1160 snd_usb_endpoint_start_quirk(ep); 1161 1162 /* 1163 * If this endpoint has a data endpoint as implicit feedback source, 1164 * don't start the urbs here. Instead, mark them all as available, 1165 * wait for the record urbs to return and queue the playback urbs 1166 * from that context. 1167 */ 1168 1169 set_bit(EP_FLAG_RUNNING, &ep->flags); 1170 1171 if (snd_usb_endpoint_implicit_feedback_sink(ep)) { 1172 for (i = 0; i < ep->nurbs; i++) { 1173 struct snd_urb_ctx *ctx = ep->urb + i; 1174 list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs); 1175 } 1176 1177 return 0; 1178 } 1179 1180 for (i = 0; i < ep->nurbs; i++) { 1181 struct urb *urb = ep->urb[i].urb; 1182 1183 if (snd_BUG_ON(!urb)) 1184 goto __error; 1185 1186 if (usb_pipeout(ep->pipe)) { 1187 prepare_outbound_urb(ep, urb->context); 1188 } else { 1189 prepare_inbound_urb(ep, urb->context); 1190 } 1191 1192 err = usb_submit_urb(urb, GFP_ATOMIC); 1193 if (err < 0) { 1194 usb_audio_err(ep->chip, 1195 "cannot submit urb %d, error %d: %s\n", 1196 i, err, usb_error_string(err)); 1197 goto __error; 1198 } 1199 set_bit(i, &ep->active_mask); 1200 } 1201 1202 return 0; 1203 1204 __error: 1205 clear_bit(EP_FLAG_RUNNING, &ep->flags); 1206 ep->use_count--; 1207 deactivate_urbs(ep, false); 1208 return -EPIPE; 1209 } 1210 1211 /** 1212 * snd_usb_endpoint_stop: stop an snd_usb_endpoint 1213 * 1214 * @ep: the endpoint to stop (may be NULL) 1215 * 1216 * A call to this function will decrement the use count of the endpoint. 1217 * In case the last user has requested the endpoint stop, the URBs will 1218 * actually be deactivated. 1219 * 1220 * Must be balanced to calls of snd_usb_endpoint_start(). 1221 * 1222 * The caller needs to synchronize the pending stop operation via 1223 * snd_usb_endpoint_sync_pending_stop(). 1224 */ 1225 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep) 1226 { 1227 if (!ep) 1228 return; 1229 1230 if (snd_BUG_ON(ep->use_count == 0)) 1231 return; 1232 1233 if (--ep->use_count == 0) { 1234 deactivate_urbs(ep, false); 1235 set_bit(EP_FLAG_STOPPING, &ep->flags); 1236 } 1237 } 1238 1239 /** 1240 * snd_usb_endpoint_deactivate: deactivate an snd_usb_endpoint 1241 * 1242 * @ep: the endpoint to deactivate 1243 * 1244 * If the endpoint is not currently in use, this functions will 1245 * deactivate its associated URBs. 1246 * 1247 * In case of any active users, this functions does nothing. 1248 */ 1249 void snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep) 1250 { 1251 if (!ep) 1252 return; 1253 1254 if (ep->use_count != 0) 1255 return; 1256 1257 deactivate_urbs(ep, true); 1258 wait_clear_urbs(ep); 1259 } 1260 1261 /** 1262 * snd_usb_endpoint_release: Tear down an snd_usb_endpoint 1263 * 1264 * @ep: the endpoint to release 1265 * 1266 * This function does not care for the endpoint's use count but will tear 1267 * down all the streaming URBs immediately. 1268 */ 1269 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep) 1270 { 1271 release_urbs(ep, 1); 1272 } 1273 1274 /** 1275 * snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint 1276 * 1277 * @ep: the endpoint to free 1278 * 1279 * This free all resources of the given ep. 1280 */ 1281 void snd_usb_endpoint_free(struct snd_usb_endpoint *ep) 1282 { 1283 kfree(ep); 1284 } 1285 1286 /** 1287 * snd_usb_handle_sync_urb: parse an USB sync packet 1288 * 1289 * @ep: the endpoint to handle the packet 1290 * @sender: the sending endpoint 1291 * @urb: the received packet 1292 * 1293 * This function is called from the context of an endpoint that received 1294 * the packet and is used to let another endpoint object handle the payload. 1295 */ 1296 void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep, 1297 struct snd_usb_endpoint *sender, 1298 const struct urb *urb) 1299 { 1300 int shift; 1301 unsigned int f; 1302 unsigned long flags; 1303 1304 snd_BUG_ON(ep == sender); 1305 1306 /* 1307 * In case the endpoint is operating in implicit feedback mode, prepare 1308 * a new outbound URB that has the same layout as the received packet 1309 * and add it to the list of pending urbs. queue_pending_output_urbs() 1310 * will take care of them later. 1311 */ 1312 if (snd_usb_endpoint_implicit_feedback_sink(ep) && 1313 ep->use_count != 0) { 1314 1315 /* implicit feedback case */ 1316 int i, bytes = 0; 1317 struct snd_urb_ctx *in_ctx; 1318 struct snd_usb_packet_info *out_packet; 1319 1320 in_ctx = urb->context; 1321 1322 /* Count overall packet size */ 1323 for (i = 0; i < in_ctx->packets; i++) 1324 if (urb->iso_frame_desc[i].status == 0) 1325 bytes += urb->iso_frame_desc[i].actual_length; 1326 1327 /* 1328 * skip empty packets. At least M-Audio's Fast Track Ultra stops 1329 * streaming once it received a 0-byte OUT URB 1330 */ 1331 if (bytes == 0) 1332 return; 1333 1334 spin_lock_irqsave(&ep->lock, flags); 1335 out_packet = ep->next_packet + ep->next_packet_write_pos; 1336 1337 /* 1338 * Iterate through the inbound packet and prepare the lengths 1339 * for the output packet. The OUT packet we are about to send 1340 * will have the same amount of payload bytes per stride as the 1341 * IN packet we just received. Since the actual size is scaled 1342 * by the stride, use the sender stride to calculate the length 1343 * in case the number of channels differ between the implicitly 1344 * fed-back endpoint and the synchronizing endpoint. 1345 */ 1346 1347 out_packet->packets = in_ctx->packets; 1348 for (i = 0; i < in_ctx->packets; i++) { 1349 if (urb->iso_frame_desc[i].status == 0) 1350 out_packet->packet_size[i] = 1351 urb->iso_frame_desc[i].actual_length / sender->stride; 1352 else 1353 out_packet->packet_size[i] = 0; 1354 } 1355 1356 ep->next_packet_write_pos++; 1357 ep->next_packet_write_pos %= MAX_URBS; 1358 spin_unlock_irqrestore(&ep->lock, flags); 1359 queue_pending_output_urbs(ep); 1360 1361 return; 1362 } 1363 1364 /* 1365 * process after playback sync complete 1366 * 1367 * Full speed devices report feedback values in 10.14 format as samples 1368 * per frame, high speed devices in 16.16 format as samples per 1369 * microframe. 1370 * 1371 * Because the Audio Class 1 spec was written before USB 2.0, many high 1372 * speed devices use a wrong interpretation, some others use an 1373 * entirely different format. 1374 * 1375 * Therefore, we cannot predict what format any particular device uses 1376 * and must detect it automatically. 1377 */ 1378 1379 if (urb->iso_frame_desc[0].status != 0 || 1380 urb->iso_frame_desc[0].actual_length < 3) 1381 return; 1382 1383 f = le32_to_cpup(urb->transfer_buffer); 1384 if (urb->iso_frame_desc[0].actual_length == 3) 1385 f &= 0x00ffffff; 1386 else 1387 f &= 0x0fffffff; 1388 1389 if (f == 0) 1390 return; 1391 1392 if (unlikely(sender->tenor_fb_quirk)) { 1393 /* 1394 * Devices based on Tenor 8802 chipsets (TEAC UD-H01 1395 * and others) sometimes change the feedback value 1396 * by +/- 0x1.0000. 1397 */ 1398 if (f < ep->freqn - 0x8000) 1399 f += 0xf000; 1400 else if (f > ep->freqn + 0x8000) 1401 f -= 0xf000; 1402 } else if (unlikely(ep->freqshift == INT_MIN)) { 1403 /* 1404 * The first time we see a feedback value, determine its format 1405 * by shifting it left or right until it matches the nominal 1406 * frequency value. This assumes that the feedback does not 1407 * differ from the nominal value more than +50% or -25%. 1408 */ 1409 shift = 0; 1410 while (f < ep->freqn - ep->freqn / 4) { 1411 f <<= 1; 1412 shift++; 1413 } 1414 while (f > ep->freqn + ep->freqn / 2) { 1415 f >>= 1; 1416 shift--; 1417 } 1418 ep->freqshift = shift; 1419 } else if (ep->freqshift >= 0) 1420 f <<= ep->freqshift; 1421 else 1422 f >>= -ep->freqshift; 1423 1424 if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) { 1425 /* 1426 * If the frequency looks valid, set it. 1427 * This value is referred to in prepare_playback_urb(). 1428 */ 1429 spin_lock_irqsave(&ep->lock, flags); 1430 ep->freqm = f; 1431 spin_unlock_irqrestore(&ep->lock, flags); 1432 } else { 1433 /* 1434 * Out of range; maybe the shift value is wrong. 1435 * Reset it so that we autodetect again the next time. 1436 */ 1437 ep->freqshift = INT_MIN; 1438 } 1439 } 1440 1441