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 *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 usb_free_coherent(ep->chip->dev, SYNC_URBS * 4, 619 ep->syncbuf, ep->sync_dma); 620 621 ep->syncbuf = NULL; 622 ep->nurbs = 0; 623 } 624 625 /* 626 * Check data endpoint for format differences 627 */ 628 static bool check_ep_params(struct snd_usb_endpoint *ep, 629 snd_pcm_format_t pcm_format, 630 unsigned int channels, 631 unsigned int period_bytes, 632 unsigned int frames_per_period, 633 unsigned int periods_per_buffer, 634 struct audioformat *fmt, 635 struct snd_usb_endpoint *sync_ep) 636 { 637 unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb; 638 unsigned int max_packs_per_period, urbs_per_period, urb_packs; 639 unsigned int max_urbs; 640 int frame_bits = snd_pcm_format_physical_width(pcm_format) * channels; 641 int tx_length_quirk = (ep->chip->tx_length_quirk && 642 usb_pipeout(ep->pipe)); 643 bool ret = 1; 644 645 if (pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) { 646 /* 647 * When operating in DSD DOP mode, the size of a sample frame 648 * in hardware differs from the actual physical format width 649 * because we need to make room for the DOP markers. 650 */ 651 frame_bits += channels << 3; 652 } 653 654 ret = ret && (ep->datainterval == fmt->datainterval); 655 ret = ret && (ep->stride == frame_bits >> 3); 656 657 switch (pcm_format) { 658 case SNDRV_PCM_FORMAT_U8: 659 ret = ret && (ep->silence_value == 0x80); 660 break; 661 case SNDRV_PCM_FORMAT_DSD_U8: 662 case SNDRV_PCM_FORMAT_DSD_U16_LE: 663 case SNDRV_PCM_FORMAT_DSD_U32_LE: 664 case SNDRV_PCM_FORMAT_DSD_U16_BE: 665 case SNDRV_PCM_FORMAT_DSD_U32_BE: 666 ret = ret && (ep->silence_value == 0x69); 667 break; 668 default: 669 ret = ret && (ep->silence_value == 0); 670 } 671 672 /* assume max. frequency is 50% higher than nominal */ 673 ret = ret && (ep->freqmax == ep->freqn + (ep->freqn >> 1)); 674 /* Round up freqmax to nearest integer in order to calculate maximum 675 * packet size, which must represent a whole number of frames. 676 * This is accomplished by adding 0x0.ffff before converting the 677 * Q16.16 format into integer. 678 * In order to accurately calculate the maximum packet size when 679 * the data interval is more than 1 (i.e. ep->datainterval > 0), 680 * multiply by the data interval prior to rounding. For instance, 681 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125) 682 * frames with a data interval of 1, but 11 (10.25) frames with a 683 * data interval of 2. 684 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the 685 * maximum datainterval value of 3, at USB full speed, higher for 686 * USB high speed, noting that ep->freqmax is in units of 687 * frames per packet in Q16.16 format.) 688 */ 689 maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) * 690 (frame_bits >> 3); 691 if (tx_length_quirk) 692 maxsize += sizeof(__le32); /* Space for length descriptor */ 693 /* but wMaxPacketSize might reduce this */ 694 if (ep->maxpacksize && ep->maxpacksize < maxsize) { 695 /* whatever fits into a max. size packet */ 696 unsigned int data_maxsize = maxsize = ep->maxpacksize; 697 698 if (tx_length_quirk) 699 /* Need to remove the length descriptor to calc freq */ 700 data_maxsize -= sizeof(__le32); 701 ret = ret && (ep->freqmax == (data_maxsize / (frame_bits >> 3)) 702 << (16 - ep->datainterval)); 703 } 704 705 if (ep->fill_max) 706 ret = ret && (ep->curpacksize == ep->maxpacksize); 707 else 708 ret = ret && (ep->curpacksize == maxsize); 709 710 if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL) { 711 packs_per_ms = 8 >> ep->datainterval; 712 max_packs_per_urb = MAX_PACKS_HS; 713 } else { 714 packs_per_ms = 1; 715 max_packs_per_urb = MAX_PACKS; 716 } 717 if (sync_ep && !snd_usb_endpoint_implicit_feedback_sink(ep)) 718 max_packs_per_urb = min(max_packs_per_urb, 719 1U << sync_ep->syncinterval); 720 max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval); 721 722 /* 723 * Capture endpoints need to use small URBs because there's no way 724 * to tell in advance where the next period will end, and we don't 725 * want the next URB to complete much after the period ends. 726 * 727 * Playback endpoints with implicit sync much use the same parameters 728 * as their corresponding capture endpoint. 729 */ 730 if (usb_pipein(ep->pipe) || 731 snd_usb_endpoint_implicit_feedback_sink(ep)) { 732 733 urb_packs = packs_per_ms; 734 /* 735 * Wireless devices can poll at a max rate of once per 4ms. 736 * For dataintervals less than 5, increase the packet count to 737 * allow the host controller to use bursting to fill in the 738 * gaps. 739 */ 740 if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_WIRELESS) { 741 int interval = ep->datainterval; 742 743 while (interval < 5) { 744 urb_packs <<= 1; 745 ++interval; 746 } 747 } 748 /* make capture URBs <= 1 ms and smaller than a period */ 749 urb_packs = min(max_packs_per_urb, urb_packs); 750 while (urb_packs > 1 && urb_packs * maxsize >= period_bytes) 751 urb_packs >>= 1; 752 ret = ret && (ep->nurbs == MAX_URBS); 753 754 /* 755 * Playback endpoints without implicit sync are adjusted so that 756 * a period fits as evenly as possible in the smallest number of 757 * URBs. The total number of URBs is adjusted to the size of the 758 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits. 759 */ 760 } else { 761 /* determine how small a packet can be */ 762 minsize = (ep->freqn >> (16 - ep->datainterval)) * 763 (frame_bits >> 3); 764 /* with sync from device, assume it can be 12% lower */ 765 if (sync_ep) 766 minsize -= minsize >> 3; 767 minsize = max(minsize, 1u); 768 769 /* how many packets will contain an entire ALSA period? */ 770 max_packs_per_period = DIV_ROUND_UP(period_bytes, minsize); 771 772 /* how many URBs will contain a period? */ 773 urbs_per_period = DIV_ROUND_UP(max_packs_per_period, 774 max_packs_per_urb); 775 /* how many packets are needed in each URB? */ 776 urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period); 777 778 /* limit the number of frames in a single URB */ 779 ret = ret && (ep->max_urb_frames == 780 DIV_ROUND_UP(frames_per_period, urbs_per_period)); 781 782 /* try to use enough URBs to contain an entire ALSA buffer */ 783 max_urbs = min((unsigned) MAX_URBS, 784 MAX_QUEUE * packs_per_ms / urb_packs); 785 ret = ret && (ep->nurbs == min(max_urbs, 786 urbs_per_period * periods_per_buffer)); 787 } 788 789 ret = ret && (ep->datainterval == fmt->datainterval); 790 ret = ret && (ep->maxpacksize == fmt->maxpacksize); 791 ret = ret && 792 (ep->fill_max == !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX)); 793 794 return ret; 795 } 796 797 /* 798 * configure a data endpoint 799 */ 800 static int data_ep_set_params(struct snd_usb_endpoint *ep, 801 snd_pcm_format_t pcm_format, 802 unsigned int channels, 803 unsigned int period_bytes, 804 unsigned int frames_per_period, 805 unsigned int periods_per_buffer, 806 struct audioformat *fmt, 807 struct snd_usb_endpoint *sync_ep) 808 { 809 unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb; 810 unsigned int max_packs_per_period, urbs_per_period, urb_packs; 811 unsigned int max_urbs, i; 812 int frame_bits = snd_pcm_format_physical_width(pcm_format) * channels; 813 int tx_length_quirk = (ep->chip->tx_length_quirk && 814 usb_pipeout(ep->pipe)); 815 816 if (pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) { 817 /* 818 * When operating in DSD DOP mode, the size of a sample frame 819 * in hardware differs from the actual physical format width 820 * because we need to make room for the DOP markers. 821 */ 822 frame_bits += channels << 3; 823 } 824 825 ep->datainterval = fmt->datainterval; 826 ep->stride = frame_bits >> 3; 827 828 switch (pcm_format) { 829 case SNDRV_PCM_FORMAT_U8: 830 ep->silence_value = 0x80; 831 break; 832 case SNDRV_PCM_FORMAT_DSD_U8: 833 case SNDRV_PCM_FORMAT_DSD_U16_LE: 834 case SNDRV_PCM_FORMAT_DSD_U32_LE: 835 case SNDRV_PCM_FORMAT_DSD_U16_BE: 836 case SNDRV_PCM_FORMAT_DSD_U32_BE: 837 ep->silence_value = 0x69; 838 break; 839 default: 840 ep->silence_value = 0; 841 } 842 843 /* assume max. frequency is 50% higher than nominal */ 844 ep->freqmax = ep->freqn + (ep->freqn >> 1); 845 /* Round up freqmax to nearest integer in order to calculate maximum 846 * packet size, which must represent a whole number of frames. 847 * This is accomplished by adding 0x0.ffff before converting the 848 * Q16.16 format into integer. 849 * In order to accurately calculate the maximum packet size when 850 * the data interval is more than 1 (i.e. ep->datainterval > 0), 851 * multiply by the data interval prior to rounding. For instance, 852 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125) 853 * frames with a data interval of 1, but 11 (10.25) frames with a 854 * data interval of 2. 855 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the 856 * maximum datainterval value of 3, at USB full speed, higher for 857 * USB high speed, noting that ep->freqmax is in units of 858 * frames per packet in Q16.16 format.) 859 */ 860 maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) * 861 (frame_bits >> 3); 862 if (tx_length_quirk) 863 maxsize += sizeof(__le32); /* Space for length descriptor */ 864 /* but wMaxPacketSize might reduce this */ 865 if (ep->maxpacksize && ep->maxpacksize < maxsize) { 866 /* whatever fits into a max. size packet */ 867 unsigned int data_maxsize = maxsize = ep->maxpacksize; 868 869 if (tx_length_quirk) 870 /* Need to remove the length descriptor to calc freq */ 871 data_maxsize -= sizeof(__le32); 872 ep->freqmax = (data_maxsize / (frame_bits >> 3)) 873 << (16 - ep->datainterval); 874 } 875 876 if (ep->fill_max) 877 ep->curpacksize = ep->maxpacksize; 878 else 879 ep->curpacksize = maxsize; 880 881 if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL) { 882 packs_per_ms = 8 >> ep->datainterval; 883 max_packs_per_urb = MAX_PACKS_HS; 884 } else { 885 packs_per_ms = 1; 886 max_packs_per_urb = MAX_PACKS; 887 } 888 if (sync_ep && !snd_usb_endpoint_implicit_feedback_sink(ep)) 889 max_packs_per_urb = min(max_packs_per_urb, 890 1U << sync_ep->syncinterval); 891 max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval); 892 893 /* 894 * Capture endpoints need to use small URBs because there's no way 895 * to tell in advance where the next period will end, and we don't 896 * want the next URB to complete much after the period ends. 897 * 898 * Playback endpoints with implicit sync much use the same parameters 899 * as their corresponding capture endpoint. 900 */ 901 if (usb_pipein(ep->pipe) || 902 snd_usb_endpoint_implicit_feedback_sink(ep)) { 903 904 urb_packs = packs_per_ms; 905 /* 906 * Wireless devices can poll at a max rate of once per 4ms. 907 * For dataintervals less than 5, increase the packet count to 908 * allow the host controller to use bursting to fill in the 909 * gaps. 910 */ 911 if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_WIRELESS) { 912 int interval = ep->datainterval; 913 while (interval < 5) { 914 urb_packs <<= 1; 915 ++interval; 916 } 917 } 918 /* make capture URBs <= 1 ms and smaller than a period */ 919 urb_packs = min(max_packs_per_urb, urb_packs); 920 while (urb_packs > 1 && urb_packs * maxsize >= period_bytes) 921 urb_packs >>= 1; 922 ep->nurbs = MAX_URBS; 923 924 /* 925 * Playback endpoints without implicit sync are adjusted so that 926 * a period fits as evenly as possible in the smallest number of 927 * URBs. The total number of URBs is adjusted to the size of the 928 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits. 929 */ 930 } else { 931 /* determine how small a packet can be */ 932 minsize = (ep->freqn >> (16 - ep->datainterval)) * 933 (frame_bits >> 3); 934 /* with sync from device, assume it can be 12% lower */ 935 if (sync_ep) 936 minsize -= minsize >> 3; 937 minsize = max(minsize, 1u); 938 939 /* how many packets will contain an entire ALSA period? */ 940 max_packs_per_period = DIV_ROUND_UP(period_bytes, minsize); 941 942 /* how many URBs will contain a period? */ 943 urbs_per_period = DIV_ROUND_UP(max_packs_per_period, 944 max_packs_per_urb); 945 /* how many packets are needed in each URB? */ 946 urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period); 947 948 /* limit the number of frames in a single URB */ 949 ep->max_urb_frames = DIV_ROUND_UP(frames_per_period, 950 urbs_per_period); 951 952 /* try to use enough URBs to contain an entire ALSA buffer */ 953 max_urbs = min((unsigned) MAX_URBS, 954 MAX_QUEUE * packs_per_ms / urb_packs); 955 ep->nurbs = min(max_urbs, urbs_per_period * periods_per_buffer); 956 } 957 958 /* allocate and initialize data urbs */ 959 for (i = 0; i < ep->nurbs; i++) { 960 struct snd_urb_ctx *u = &ep->urb[i]; 961 u->index = i; 962 u->ep = ep; 963 u->packets = urb_packs; 964 u->buffer_size = maxsize * u->packets; 965 966 if (fmt->fmt_type == UAC_FORMAT_TYPE_II) 967 u->packets++; /* for transfer delimiter */ 968 u->urb = usb_alloc_urb(u->packets, GFP_KERNEL); 969 if (!u->urb) 970 goto out_of_memory; 971 972 u->urb->transfer_buffer = 973 usb_alloc_coherent(ep->chip->dev, u->buffer_size, 974 GFP_KERNEL, &u->urb->transfer_dma); 975 if (!u->urb->transfer_buffer) 976 goto out_of_memory; 977 u->urb->pipe = ep->pipe; 978 u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP; 979 u->urb->interval = 1 << ep->datainterval; 980 u->urb->context = u; 981 u->urb->complete = snd_complete_urb; 982 INIT_LIST_HEAD(&u->ready_list); 983 } 984 985 return 0; 986 987 out_of_memory: 988 release_urbs(ep, 0); 989 return -ENOMEM; 990 } 991 992 /* 993 * configure a sync endpoint 994 */ 995 static int sync_ep_set_params(struct snd_usb_endpoint *ep) 996 { 997 int i; 998 999 ep->syncbuf = usb_alloc_coherent(ep->chip->dev, SYNC_URBS * 4, 1000 GFP_KERNEL, &ep->sync_dma); 1001 if (!ep->syncbuf) 1002 return -ENOMEM; 1003 1004 for (i = 0; i < SYNC_URBS; i++) { 1005 struct snd_urb_ctx *u = &ep->urb[i]; 1006 u->index = i; 1007 u->ep = ep; 1008 u->packets = 1; 1009 u->urb = usb_alloc_urb(1, GFP_KERNEL); 1010 if (!u->urb) 1011 goto out_of_memory; 1012 u->urb->transfer_buffer = ep->syncbuf + i * 4; 1013 u->urb->transfer_dma = ep->sync_dma + i * 4; 1014 u->urb->transfer_buffer_length = 4; 1015 u->urb->pipe = ep->pipe; 1016 u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP; 1017 u->urb->number_of_packets = 1; 1018 u->urb->interval = 1 << ep->syncinterval; 1019 u->urb->context = u; 1020 u->urb->complete = snd_complete_urb; 1021 } 1022 1023 ep->nurbs = SYNC_URBS; 1024 1025 return 0; 1026 1027 out_of_memory: 1028 release_urbs(ep, 0); 1029 return -ENOMEM; 1030 } 1031 1032 /** 1033 * snd_usb_endpoint_set_params: configure an snd_usb_endpoint 1034 * 1035 * @ep: the snd_usb_endpoint to configure 1036 * @pcm_format: the audio fomat. 1037 * @channels: the number of audio channels. 1038 * @period_bytes: the number of bytes in one alsa period. 1039 * @period_frames: the number of frames in one alsa period. 1040 * @buffer_periods: the number of periods in one alsa buffer. 1041 * @rate: the frame rate. 1042 * @fmt: the USB audio format information 1043 * @sync_ep: the sync endpoint to use, if any 1044 * 1045 * Determine the number of URBs to be used on this endpoint. 1046 * An endpoint must be configured before it can be started. 1047 * An endpoint that is already running can not be reconfigured. 1048 */ 1049 int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep, 1050 snd_pcm_format_t pcm_format, 1051 unsigned int channels, 1052 unsigned int period_bytes, 1053 unsigned int period_frames, 1054 unsigned int buffer_periods, 1055 unsigned int rate, 1056 struct audioformat *fmt, 1057 struct snd_usb_endpoint *sync_ep) 1058 { 1059 int err; 1060 1061 if (ep->use_count != 0) { 1062 bool check = ep->is_implicit_feedback && 1063 check_ep_params(ep, pcm_format, 1064 channels, period_bytes, 1065 period_frames, buffer_periods, 1066 fmt, sync_ep); 1067 1068 if (!check) { 1069 usb_audio_warn(ep->chip, 1070 "Unable to change format on ep #%x: already in use\n", 1071 ep->ep_num); 1072 return -EBUSY; 1073 } 1074 1075 usb_audio_dbg(ep->chip, 1076 "Ep #%x already in use as implicit feedback but format not changed\n", 1077 ep->ep_num); 1078 return 0; 1079 } 1080 1081 /* release old buffers, if any */ 1082 release_urbs(ep, 0); 1083 1084 ep->datainterval = fmt->datainterval; 1085 ep->maxpacksize = fmt->maxpacksize; 1086 ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX); 1087 1088 if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL) { 1089 ep->freqn = get_usb_full_speed_rate(rate); 1090 ep->pps = 1000 >> ep->datainterval; 1091 } else { 1092 ep->freqn = get_usb_high_speed_rate(rate); 1093 ep->pps = 8000 >> ep->datainterval; 1094 } 1095 1096 ep->sample_rem = rate % ep->pps; 1097 ep->packsize[0] = rate / ep->pps; 1098 ep->packsize[1] = (rate + (ep->pps - 1)) / ep->pps; 1099 1100 /* calculate the frequency in 16.16 format */ 1101 ep->freqm = ep->freqn; 1102 ep->freqshift = INT_MIN; 1103 1104 ep->phase = 0; 1105 1106 switch (ep->type) { 1107 case SND_USB_ENDPOINT_TYPE_DATA: 1108 err = data_ep_set_params(ep, pcm_format, channels, 1109 period_bytes, period_frames, 1110 buffer_periods, fmt, sync_ep); 1111 break; 1112 case SND_USB_ENDPOINT_TYPE_SYNC: 1113 err = sync_ep_set_params(ep); 1114 break; 1115 default: 1116 err = -EINVAL; 1117 } 1118 1119 usb_audio_dbg(ep->chip, 1120 "Setting params for ep #%x (type %d, %d urbs), ret=%d\n", 1121 ep->ep_num, ep->type, ep->nurbs, err); 1122 1123 return err; 1124 } 1125 1126 /** 1127 * snd_usb_endpoint_start: start an snd_usb_endpoint 1128 * 1129 * @ep: the endpoint to start 1130 * 1131 * A call to this function will increment the use count of the endpoint. 1132 * In case it is not already running, the URBs for this endpoint will be 1133 * submitted. Otherwise, this function does nothing. 1134 * 1135 * Must be balanced to calls of snd_usb_endpoint_stop(). 1136 * 1137 * Returns an error if the URB submission failed, 0 in all other cases. 1138 */ 1139 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep) 1140 { 1141 int err; 1142 unsigned int i; 1143 1144 if (atomic_read(&ep->chip->shutdown)) 1145 return -EBADFD; 1146 1147 /* already running? */ 1148 if (++ep->use_count != 1) 1149 return 0; 1150 1151 /* just to be sure */ 1152 deactivate_urbs(ep, false); 1153 1154 ep->active_mask = 0; 1155 ep->unlink_mask = 0; 1156 ep->phase = 0; 1157 ep->sample_accum = 0; 1158 1159 snd_usb_endpoint_start_quirk(ep); 1160 1161 /* 1162 * If this endpoint has a data endpoint as implicit feedback source, 1163 * don't start the urbs here. Instead, mark them all as available, 1164 * wait for the record urbs to return and queue the playback urbs 1165 * from that context. 1166 */ 1167 1168 set_bit(EP_FLAG_RUNNING, &ep->flags); 1169 1170 if (snd_usb_endpoint_implicit_feedback_sink(ep)) { 1171 for (i = 0; i < ep->nurbs; i++) { 1172 struct snd_urb_ctx *ctx = ep->urb + i; 1173 list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs); 1174 } 1175 1176 return 0; 1177 } 1178 1179 for (i = 0; i < ep->nurbs; i++) { 1180 struct urb *urb = ep->urb[i].urb; 1181 1182 if (snd_BUG_ON(!urb)) 1183 goto __error; 1184 1185 if (usb_pipeout(ep->pipe)) { 1186 prepare_outbound_urb(ep, urb->context); 1187 } else { 1188 prepare_inbound_urb(ep, urb->context); 1189 } 1190 1191 err = usb_submit_urb(urb, GFP_ATOMIC); 1192 if (err < 0) { 1193 usb_audio_err(ep->chip, 1194 "cannot submit urb %d, error %d: %s\n", 1195 i, err, usb_error_string(err)); 1196 goto __error; 1197 } 1198 set_bit(i, &ep->active_mask); 1199 } 1200 1201 return 0; 1202 1203 __error: 1204 clear_bit(EP_FLAG_RUNNING, &ep->flags); 1205 ep->use_count--; 1206 deactivate_urbs(ep, false); 1207 return -EPIPE; 1208 } 1209 1210 /** 1211 * snd_usb_endpoint_stop: stop an snd_usb_endpoint 1212 * 1213 * @ep: the endpoint to stop (may be NULL) 1214 * 1215 * A call to this function will decrement the use count of the endpoint. 1216 * In case the last user has requested the endpoint stop, the URBs will 1217 * actually be deactivated. 1218 * 1219 * Must be balanced to calls of snd_usb_endpoint_start(). 1220 * 1221 * The caller needs to synchronize the pending stop operation via 1222 * snd_usb_endpoint_sync_pending_stop(). 1223 */ 1224 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep) 1225 { 1226 if (!ep) 1227 return; 1228 1229 if (snd_BUG_ON(ep->use_count == 0)) 1230 return; 1231 1232 if (--ep->use_count == 0) { 1233 deactivate_urbs(ep, false); 1234 set_bit(EP_FLAG_STOPPING, &ep->flags); 1235 } 1236 } 1237 1238 /** 1239 * snd_usb_endpoint_deactivate: deactivate an snd_usb_endpoint 1240 * 1241 * @ep: the endpoint to deactivate 1242 * 1243 * If the endpoint is not currently in use, this functions will 1244 * deactivate its associated URBs. 1245 * 1246 * In case of any active users, this functions does nothing. 1247 */ 1248 void snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep) 1249 { 1250 if (!ep) 1251 return; 1252 1253 if (ep->use_count != 0) 1254 return; 1255 1256 deactivate_urbs(ep, true); 1257 wait_clear_urbs(ep); 1258 } 1259 1260 /** 1261 * snd_usb_endpoint_release: Tear down an snd_usb_endpoint 1262 * 1263 * @ep: the endpoint to release 1264 * 1265 * This function does not care for the endpoint's use count but will tear 1266 * down all the streaming URBs immediately. 1267 */ 1268 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep) 1269 { 1270 release_urbs(ep, 1); 1271 } 1272 1273 /** 1274 * snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint 1275 * 1276 * @ep: the endpoint to free 1277 * 1278 * This free all resources of the given ep. 1279 */ 1280 void snd_usb_endpoint_free(struct snd_usb_endpoint *ep) 1281 { 1282 kfree(ep); 1283 } 1284 1285 /** 1286 * snd_usb_handle_sync_urb: parse an USB sync packet 1287 * 1288 * @ep: the endpoint to handle the packet 1289 * @sender: the sending endpoint 1290 * @urb: the received packet 1291 * 1292 * This function is called from the context of an endpoint that received 1293 * the packet and is used to let another endpoint object handle the payload. 1294 */ 1295 void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep, 1296 struct snd_usb_endpoint *sender, 1297 const struct urb *urb) 1298 { 1299 int shift; 1300 unsigned int f; 1301 unsigned long flags; 1302 1303 snd_BUG_ON(ep == sender); 1304 1305 /* 1306 * In case the endpoint is operating in implicit feedback mode, prepare 1307 * a new outbound URB that has the same layout as the received packet 1308 * and add it to the list of pending urbs. queue_pending_output_urbs() 1309 * will take care of them later. 1310 */ 1311 if (snd_usb_endpoint_implicit_feedback_sink(ep) && 1312 ep->use_count != 0) { 1313 1314 /* implicit feedback case */ 1315 int i, bytes = 0; 1316 struct snd_urb_ctx *in_ctx; 1317 struct snd_usb_packet_info *out_packet; 1318 1319 in_ctx = urb->context; 1320 1321 /* Count overall packet size */ 1322 for (i = 0; i < in_ctx->packets; i++) 1323 if (urb->iso_frame_desc[i].status == 0) 1324 bytes += urb->iso_frame_desc[i].actual_length; 1325 1326 /* 1327 * skip empty packets. At least M-Audio's Fast Track Ultra stops 1328 * streaming once it received a 0-byte OUT URB 1329 */ 1330 if (bytes == 0) 1331 return; 1332 1333 spin_lock_irqsave(&ep->lock, flags); 1334 out_packet = ep->next_packet + ep->next_packet_write_pos; 1335 1336 /* 1337 * Iterate through the inbound packet and prepare the lengths 1338 * for the output packet. The OUT packet we are about to send 1339 * will have the same amount of payload bytes per stride as the 1340 * IN packet we just received. Since the actual size is scaled 1341 * by the stride, use the sender stride to calculate the length 1342 * in case the number of channels differ between the implicitly 1343 * fed-back endpoint and the synchronizing endpoint. 1344 */ 1345 1346 out_packet->packets = in_ctx->packets; 1347 for (i = 0; i < in_ctx->packets; i++) { 1348 if (urb->iso_frame_desc[i].status == 0) 1349 out_packet->packet_size[i] = 1350 urb->iso_frame_desc[i].actual_length / sender->stride; 1351 else 1352 out_packet->packet_size[i] = 0; 1353 } 1354 1355 ep->next_packet_write_pos++; 1356 ep->next_packet_write_pos %= MAX_URBS; 1357 spin_unlock_irqrestore(&ep->lock, flags); 1358 queue_pending_output_urbs(ep); 1359 1360 return; 1361 } 1362 1363 /* 1364 * process after playback sync complete 1365 * 1366 * Full speed devices report feedback values in 10.14 format as samples 1367 * per frame, high speed devices in 16.16 format as samples per 1368 * microframe. 1369 * 1370 * Because the Audio Class 1 spec was written before USB 2.0, many high 1371 * speed devices use a wrong interpretation, some others use an 1372 * entirely different format. 1373 * 1374 * Therefore, we cannot predict what format any particular device uses 1375 * and must detect it automatically. 1376 */ 1377 1378 if (urb->iso_frame_desc[0].status != 0 || 1379 urb->iso_frame_desc[0].actual_length < 3) 1380 return; 1381 1382 f = le32_to_cpup(urb->transfer_buffer); 1383 if (urb->iso_frame_desc[0].actual_length == 3) 1384 f &= 0x00ffffff; 1385 else 1386 f &= 0x0fffffff; 1387 1388 if (f == 0) 1389 return; 1390 1391 if (unlikely(sender->tenor_fb_quirk)) { 1392 /* 1393 * Devices based on Tenor 8802 chipsets (TEAC UD-H01 1394 * and others) sometimes change the feedback value 1395 * by +/- 0x1.0000. 1396 */ 1397 if (f < ep->freqn - 0x8000) 1398 f += 0xf000; 1399 else if (f > ep->freqn + 0x8000) 1400 f -= 0xf000; 1401 } else if (unlikely(ep->freqshift == INT_MIN)) { 1402 /* 1403 * The first time we see a feedback value, determine its format 1404 * by shifting it left or right until it matches the nominal 1405 * frequency value. This assumes that the feedback does not 1406 * differ from the nominal value more than +50% or -25%. 1407 */ 1408 shift = 0; 1409 while (f < ep->freqn - ep->freqn / 4) { 1410 f <<= 1; 1411 shift++; 1412 } 1413 while (f > ep->freqn + ep->freqn / 2) { 1414 f >>= 1; 1415 shift--; 1416 } 1417 ep->freqshift = shift; 1418 } else if (ep->freqshift >= 0) 1419 f <<= ep->freqshift; 1420 else 1421 f >>= -ep->freqshift; 1422 1423 if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) { 1424 /* 1425 * If the frequency looks valid, set it. 1426 * This value is referred to in prepare_playback_urb(). 1427 */ 1428 spin_lock_irqsave(&ep->lock, flags); 1429 ep->freqm = f; 1430 spin_unlock_irqrestore(&ep->lock, flags); 1431 } else { 1432 /* 1433 * Out of range; maybe the shift value is wrong. 1434 * Reset it so that we autodetect again the next time. 1435 */ 1436 ep->freqshift = INT_MIN; 1437 } 1438 } 1439 1440