1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 */
   4
   5#include <linux/init.h>
   6#include <linux/slab.h>
   7#include <linux/bitrev.h>
   8#include <linux/ratelimit.h>
   9#include <linux/usb.h>
  10#include <linux/usb/audio.h>
  11#include <linux/usb/audio-v2.h>
  12
  13#include <sound/core.h>
  14#include <sound/pcm.h>
  15#include <sound/pcm_params.h>
  16
  17#include "usbaudio.h"
  18#include "card.h"
  19#include "quirks.h"
  20#include "debug.h"
  21#include "endpoint.h"
  22#include "helper.h"
  23#include "pcm.h"
  24#include "clock.h"
  25#include "power.h"
  26#include "media.h"
  27
  28#define SUBSTREAM_FLAG_DATA_EP_STARTED	0
  29#define SUBSTREAM_FLAG_SYNC_EP_STARTED	1
  30
  31/* return the estimated delay based on USB frame counters */
  32snd_pcm_uframes_t snd_usb_pcm_delay(struct snd_usb_substream *subs,
  33				    unsigned int rate)
  34{
  35	int current_frame_number;
  36	int frame_diff;
  37	int est_delay;
  38
  39	if (!subs->last_delay)
  40		return 0; /* short path */
  41
  42	current_frame_number = usb_get_current_frame_number(subs->dev);
  43	/*
  44	 * HCD implementations use different widths, use lower 8 bits.
  45	 * The delay will be managed up to 256ms, which is more than
  46	 * enough
  47	 */
  48	frame_diff = (current_frame_number - subs->last_frame_number) & 0xff;
  49
  50	/* Approximation based on number of samples per USB frame (ms),
  51	   some truncation for 44.1 but the estimate is good enough */
  52	est_delay =  frame_diff * rate / 1000;
  53	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK)
  54		est_delay = subs->last_delay - est_delay;
  55	else
  56		est_delay = subs->last_delay + est_delay;
  57
  58	if (est_delay < 0)
  59		est_delay = 0;
  60	return est_delay;
  61}
  62
  63/*
  64 * return the current pcm pointer.  just based on the hwptr_done value.
  65 */
  66static snd_pcm_uframes_t snd_usb_pcm_pointer(struct snd_pcm_substream *substream)
  67{
  68	struct snd_usb_substream *subs = substream->runtime->private_data;
  69	unsigned int hwptr_done;
  70
  71	if (atomic_read(&subs->stream->chip->shutdown))
  72		return SNDRV_PCM_POS_XRUN;
  73	spin_lock(&subs->lock);
  74	hwptr_done = subs->hwptr_done;
  75	substream->runtime->delay = snd_usb_pcm_delay(subs,
  76						substream->runtime->rate);
  77	spin_unlock(&subs->lock);
  78	return hwptr_done / (substream->runtime->frame_bits >> 3);
  79}
  80
  81/*
  82 * find a matching audio format
  83 */
  84static struct audioformat *find_format(struct snd_usb_substream *subs)
  85{
  86	struct audioformat *fp;
  87	struct audioformat *found = NULL;
  88	int cur_attr = 0, attr;
  89
  90	list_for_each_entry(fp, &subs->fmt_list, list) {
  91		if (!(fp->formats & pcm_format_to_bits(subs->pcm_format)))
  92			continue;
  93		if (fp->channels != subs->channels)
  94			continue;
  95		if (subs->cur_rate < fp->rate_min ||
  96		    subs->cur_rate > fp->rate_max)
  97			continue;
  98		if (! (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)) {
  99			unsigned int i;
 100			for (i = 0; i < fp->nr_rates; i++)
 101				if (fp->rate_table[i] == subs->cur_rate)
 102					break;
 103			if (i >= fp->nr_rates)
 104				continue;
 105		}
 106		attr = fp->ep_attr & USB_ENDPOINT_SYNCTYPE;
 107		if (! found) {
 108			found = fp;
 109			cur_attr = attr;
 110			continue;
 111		}
 112		/* avoid async out and adaptive in if the other method
 113		 * supports the same format.
 114		 * this is a workaround for the case like
 115		 * M-audio audiophile USB.
 116		 */
 117		if (attr != cur_attr) {
 118			if ((attr == USB_ENDPOINT_SYNC_ASYNC &&
 119			     subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
 120			    (attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
 121			     subs->direction == SNDRV_PCM_STREAM_CAPTURE))
 122				continue;
 123			if ((cur_attr == USB_ENDPOINT_SYNC_ASYNC &&
 124			     subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
 125			    (cur_attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
 126			     subs->direction == SNDRV_PCM_STREAM_CAPTURE)) {
 127				found = fp;
 128				cur_attr = attr;
 129				continue;
 130			}
 131		}
 132		/* find the format with the largest max. packet size */
 133		if (fp->maxpacksize > found->maxpacksize) {
 134			found = fp;
 135			cur_attr = attr;
 136		}
 137	}
 138	return found;
 139}
 140
 141static int init_pitch_v1(struct snd_usb_audio *chip, int iface,
 142			 struct usb_host_interface *alts,
 143			 struct audioformat *fmt)
 144{
 145	struct usb_device *dev = chip->dev;
 146	unsigned int ep;
 147	unsigned char data[1];
 148	int err;
 149
 150	if (get_iface_desc(alts)->bNumEndpoints < 1)
 151		return -EINVAL;
 152	ep = get_endpoint(alts, 0)->bEndpointAddress;
 153
 154	data[0] = 1;
 155	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
 156			      USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_OUT,
 157			      UAC_EP_CS_ATTR_PITCH_CONTROL << 8, ep,
 158			      data, sizeof(data));
 159	if (err < 0) {
 160		usb_audio_err(chip, "%d:%d: cannot set enable PITCH\n",
 161			      iface, ep);
 162		return err;
 163	}
 164
 165	return 0;
 166}
 167
 168static int init_pitch_v2(struct snd_usb_audio *chip, int iface,
 169			 struct usb_host_interface *alts,
 170			 struct audioformat *fmt)
 171{
 172	struct usb_device *dev = chip->dev;
 173	unsigned char data[1];
 174	int err;
 175
 176	data[0] = 1;
 177	err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
 178			      USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
 179			      UAC2_EP_CS_PITCH << 8, 0,
 180			      data, sizeof(data));
 181	if (err < 0) {
 182		usb_audio_err(chip, "%d:%d: cannot set enable PITCH (v2)\n",
 183			      iface, fmt->altsetting);
 184		return err;
 185	}
 186
 187	return 0;
 188}
 189
 190/*
 191 * initialize the pitch control and sample rate
 192 */
 193int snd_usb_init_pitch(struct snd_usb_audio *chip, int iface,
 194		       struct usb_host_interface *alts,
 195		       struct audioformat *fmt)
 196{
 197	/* if endpoint doesn't have pitch control, bail out */
 198	if (!(fmt->attributes & UAC_EP_CS_ATTR_PITCH_CONTROL))
 199		return 0;
 200
 201	switch (fmt->protocol) {
 202	case UAC_VERSION_1:
 203	default:
 204		return init_pitch_v1(chip, iface, alts, fmt);
 205
 206	case UAC_VERSION_2:
 207		return init_pitch_v2(chip, iface, alts, fmt);
 208	}
 209}
 210
 211static int start_endpoints(struct snd_usb_substream *subs)
 212{
 213	int err;
 214
 215	if (!subs->data_endpoint)
 216		return -EINVAL;
 217
 218	if (!test_and_set_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
 219		struct snd_usb_endpoint *ep = subs->data_endpoint;
 220
 221		dev_dbg(&subs->dev->dev, "Starting data EP @%p\n", ep);
 222
 223		ep->data_subs = subs;
 224		err = snd_usb_endpoint_start(ep);
 225		if (err < 0) {
 226			clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags);
 227			return err;
 228		}
 229	}
 230
 231	if (subs->sync_endpoint &&
 232	    !test_and_set_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
 233		struct snd_usb_endpoint *ep = subs->sync_endpoint;
 234
 235		if (subs->data_endpoint->iface != subs->sync_endpoint->iface ||
 236		    subs->data_endpoint->altsetting != subs->sync_endpoint->altsetting) {
 237			err = usb_set_interface(subs->dev,
 238						subs->sync_endpoint->iface,
 239						subs->sync_endpoint->altsetting);
 240			if (err < 0) {
 241				clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags);
 242				dev_err(&subs->dev->dev,
 243					   "%d:%d: cannot set interface (%d)\n",
 244					   subs->sync_endpoint->iface,
 245					   subs->sync_endpoint->altsetting, err);
 246				return -EIO;
 247			}
 248		}
 249
 250		dev_dbg(&subs->dev->dev, "Starting sync EP @%p\n", ep);
 251
 252		ep->sync_slave = subs->data_endpoint;
 253		err = snd_usb_endpoint_start(ep);
 254		if (err < 0) {
 255			clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags);
 256			return err;
 257		}
 258	}
 259
 260	return 0;
 261}
 262
 263static void stop_endpoints(struct snd_usb_substream *subs, bool wait)
 
 
 
 
 
 
 264{
 265	if (test_and_clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags))
 266		snd_usb_endpoint_stop(subs->sync_endpoint);
 267
 268	if (test_and_clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags))
 269		snd_usb_endpoint_stop(subs->data_endpoint);
 
 
 
 
 
 
 270
 271	if (wait) {
 272		snd_usb_endpoint_sync_pending_stop(subs->sync_endpoint);
 273		snd_usb_endpoint_sync_pending_stop(subs->data_endpoint);
 274	}
 
 275}
 276
 277static int search_roland_implicit_fb(struct usb_device *dev, int ifnum,
 278				     unsigned int altsetting,
 279				     struct usb_host_interface **alts,
 280				     unsigned int *ep)
 281{
 282	struct usb_interface *iface;
 283	struct usb_interface_descriptor *altsd;
 284	struct usb_endpoint_descriptor *epd;
 285
 286	iface = usb_ifnum_to_if(dev, ifnum);
 287	if (!iface || iface->num_altsetting < altsetting + 1)
 288		return -ENOENT;
 289	*alts = &iface->altsetting[altsetting];
 290	altsd = get_iface_desc(*alts);
 291	if (altsd->bAlternateSetting != altsetting ||
 292	    altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC ||
 293	    (altsd->bInterfaceSubClass != 2 &&
 294	     altsd->bInterfaceProtocol != 2   ) ||
 295	    altsd->bNumEndpoints < 1)
 296		return -ENOENT;
 297	epd = get_endpoint(*alts, 0);
 298	if (!usb_endpoint_is_isoc_in(epd) ||
 299	    (epd->bmAttributes & USB_ENDPOINT_USAGE_MASK) !=
 300					USB_ENDPOINT_USAGE_IMPLICIT_FB)
 301		return -ENOENT;
 302	*ep = epd->bEndpointAddress;
 303	return 0;
 304}
 305
 306/* Setup an implicit feedback endpoint from a quirk. Returns 0 if no quirk
 307 * applies. Returns 1 if a quirk was found.
 308 */
 309static int set_sync_ep_implicit_fb_quirk(struct snd_usb_substream *subs,
 310					 struct usb_device *dev,
 311					 struct usb_interface_descriptor *altsd,
 312					 unsigned int attr)
 313{
 314	struct usb_host_interface *alts;
 315	struct usb_interface *iface;
 316	unsigned int ep;
 317	unsigned int ifnum;
 318
 319	/* Implicit feedback sync EPs consumers are always playback EPs */
 320	if (subs->direction != SNDRV_PCM_STREAM_PLAYBACK)
 321		return 0;
 322
 323	switch (subs->stream->chip->usb_id) {
 324	case USB_ID(0x0763, 0x2030): /* M-Audio Fast Track C400 */
 325	case USB_ID(0x0763, 0x2031): /* M-Audio Fast Track C600 */
 326		ep = 0x81;
 327		ifnum = 3;
 328		goto add_sync_ep_from_ifnum;
 329	case USB_ID(0x0763, 0x2080): /* M-Audio FastTrack Ultra */
 330	case USB_ID(0x0763, 0x2081):
 331		ep = 0x81;
 332		ifnum = 2;
 333		goto add_sync_ep_from_ifnum;
 334	case USB_ID(0x2466, 0x8003): /* Fractal Audio Axe-Fx II */
 335		ep = 0x86;
 336		ifnum = 2;
 337		goto add_sync_ep_from_ifnum;
 338	case USB_ID(0x2466, 0x8010): /* Fractal Audio Axe-Fx III */
 339		ep = 0x81;
 340		ifnum = 2;
 341		goto add_sync_ep_from_ifnum;
 342	case USB_ID(0x1397, 0x0001): /* Behringer UFX1604 */
 343	case USB_ID(0x1397, 0x0002): /* Behringer UFX1204 */
 344		ep = 0x81;
 345		ifnum = 1;
 346		goto add_sync_ep_from_ifnum;
 347	case USB_ID(0x07fd, 0x0004): /* MOTU MicroBook II */
 
 
 
 
 
 348		ep = 0x84;
 349		ifnum = 0;
 350		goto add_sync_ep_from_ifnum;
 
 
 
 
 
 
 
 
 
 
 
 
 
 351	case USB_ID(0x0582, 0x01d8): /* BOSS Katana */
 352		/* BOSS Katana amplifiers do not need quirks */
 353		return 0;
 354	}
 355
 356	if (attr == USB_ENDPOINT_SYNC_ASYNC &&
 357	    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
 358	    altsd->bInterfaceProtocol == 2 &&
 359	    altsd->bNumEndpoints == 1 &&
 360	    USB_ID_VENDOR(subs->stream->chip->usb_id) == 0x0582 /* Roland */ &&
 361	    search_roland_implicit_fb(dev, altsd->bInterfaceNumber + 1,
 362				      altsd->bAlternateSetting,
 363				      &alts, &ep) >= 0) {
 364		goto add_sync_ep;
 365	}
 366
 367	/* No quirk */
 368	return 0;
 369
 370add_sync_ep_from_ifnum:
 371	iface = usb_ifnum_to_if(dev, ifnum);
 372
 373	if (!iface || iface->num_altsetting == 0)
 374		return -EINVAL;
 375
 376	alts = &iface->altsetting[1];
 377
 378add_sync_ep:
 379	subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
 380						   alts, ep, !subs->direction,
 381						   SND_USB_ENDPOINT_TYPE_DATA);
 382	if (!subs->sync_endpoint)
 383		return -EINVAL;
 384
 
 
 385	subs->data_endpoint->sync_master = subs->sync_endpoint;
 386
 387	return 1;
 388}
 389
 390static int set_sync_endpoint(struct snd_usb_substream *subs,
 391			     struct audioformat *fmt,
 392			     struct usb_device *dev,
 393			     struct usb_host_interface *alts,
 394			     struct usb_interface_descriptor *altsd)
 395{
 396	int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
 397	unsigned int ep, attr;
 398	bool implicit_fb;
 399	int err;
 400
 401	/* we need a sync pipe in async OUT or adaptive IN mode */
 402	/* check the number of EP, since some devices have broken
 403	 * descriptors which fool us.  if it has only one EP,
 404	 * assume it as adaptive-out or sync-in.
 405	 */
 406	attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
 407
 408	if ((is_playback && (attr != USB_ENDPOINT_SYNC_ASYNC)) ||
 409		(!is_playback && (attr != USB_ENDPOINT_SYNC_ADAPTIVE))) {
 410
 411		/*
 412		 * In these modes the notion of sync_endpoint is irrelevant.
 413		 * Reset pointers to avoid using stale data from previously
 414		 * used settings, e.g. when configuration and endpoints were
 415		 * changed
 416		 */
 417
 418		subs->sync_endpoint = NULL;
 419		subs->data_endpoint->sync_master = NULL;
 420	}
 421
 422	err = set_sync_ep_implicit_fb_quirk(subs, dev, altsd, attr);
 423	if (err < 0)
 424		return err;
 425
 426	/* endpoint set by quirk */
 427	if (err > 0)
 428		return 0;
 429
 430	if (altsd->bNumEndpoints < 2)
 431		return 0;
 432
 433	if ((is_playback && (attr == USB_ENDPOINT_SYNC_SYNC ||
 434			     attr == USB_ENDPOINT_SYNC_ADAPTIVE)) ||
 435	    (!is_playback && attr != USB_ENDPOINT_SYNC_ADAPTIVE))
 436		return 0;
 437
 438	/*
 439	 * In case of illegal SYNC_NONE for OUT endpoint, we keep going to see
 440	 * if we don't find a sync endpoint, as on M-Audio Transit. In case of
 441	 * error fall back to SYNC mode and don't create sync endpoint
 442	 */
 443
 444	/* check sync-pipe endpoint */
 445	/* ... and check descriptor size before accessing bSynchAddress
 446	   because there is a version of the SB Audigy 2 NX firmware lacking
 447	   the audio fields in the endpoint descriptors */
 448	if ((get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) != USB_ENDPOINT_XFER_ISOC ||
 449	    (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
 450	     get_endpoint(alts, 1)->bSynchAddress != 0)) {
 451		dev_err(&dev->dev,
 452			"%d:%d : invalid sync pipe. bmAttributes %02x, bLength %d, bSynchAddress %02x\n",
 453			   fmt->iface, fmt->altsetting,
 454			   get_endpoint(alts, 1)->bmAttributes,
 455			   get_endpoint(alts, 1)->bLength,
 456			   get_endpoint(alts, 1)->bSynchAddress);
 457		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
 458			return 0;
 459		return -EINVAL;
 460	}
 461	ep = get_endpoint(alts, 1)->bEndpointAddress;
 462	if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
 463	    get_endpoint(alts, 0)->bSynchAddress != 0 &&
 464	    ((is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
 465	     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
 466		dev_err(&dev->dev,
 467			"%d:%d : invalid sync pipe. is_playback %d, ep %02x, bSynchAddress %02x\n",
 468			   fmt->iface, fmt->altsetting,
 469			   is_playback, ep, get_endpoint(alts, 0)->bSynchAddress);
 470		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
 471			return 0;
 472		return -EINVAL;
 473	}
 474
 475	implicit_fb = (get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_USAGE_MASK)
 476			== USB_ENDPOINT_USAGE_IMPLICIT_FB;
 477
 478	subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
 479						   alts, ep, !subs->direction,
 480						   implicit_fb ?
 481							SND_USB_ENDPOINT_TYPE_DATA :
 482							SND_USB_ENDPOINT_TYPE_SYNC);
 
 483	if (!subs->sync_endpoint) {
 484		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
 485			return 0;
 486		return -EINVAL;
 487	}
 488
 
 
 489	subs->data_endpoint->sync_master = subs->sync_endpoint;
 490
 491	return 0;
 492}
 493
 494/*
 495 * find a matching format and set up the interface
 496 */
 497static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
 498{
 499	struct usb_device *dev = subs->dev;
 500	struct usb_host_interface *alts;
 501	struct usb_interface_descriptor *altsd;
 502	struct usb_interface *iface;
 503	int err;
 504
 505	iface = usb_ifnum_to_if(dev, fmt->iface);
 506	if (WARN_ON(!iface))
 507		return -EINVAL;
 508	alts = usb_altnum_to_altsetting(iface, fmt->altsetting);
 509	altsd = get_iface_desc(alts);
 510	if (WARN_ON(altsd->bAlternateSetting != fmt->altsetting))
 511		return -EINVAL;
 
 512
 513	if (fmt == subs->cur_audiofmt)
 514		return 0;
 515
 516	/* close the old interface */
 517	if (subs->interface >= 0 && subs->interface != fmt->iface) {
 518		if (!subs->stream->chip->keep_iface) {
 519			err = usb_set_interface(subs->dev, subs->interface, 0);
 520			if (err < 0) {
 521				dev_err(&dev->dev,
 522					"%d:%d: return to setting 0 failed (%d)\n",
 523					fmt->iface, fmt->altsetting, err);
 524				return -EIO;
 525			}
 526		}
 527		subs->interface = -1;
 528		subs->altset_idx = 0;
 529	}
 530
 
 
 
 531	/* set interface */
 532	if (iface->cur_altsetting != alts) {
 533		err = snd_usb_select_mode_quirk(subs, fmt);
 534		if (err < 0)
 535			return -EIO;
 536
 537		err = usb_set_interface(dev, fmt->iface, fmt->altsetting);
 538		if (err < 0) {
 539			dev_err(&dev->dev,
 540				"%d:%d: usb_set_interface failed (%d)\n",
 541				fmt->iface, fmt->altsetting, err);
 542			return -EIO;
 543		}
 544		dev_dbg(&dev->dev, "setting usb interface %d:%d\n",
 545			fmt->iface, fmt->altsetting);
 546		snd_usb_set_interface_quirk(dev);
 547	}
 548
 549	subs->interface = fmt->iface;
 550	subs->altset_idx = fmt->altset_idx;
 551	subs->data_endpoint = snd_usb_add_endpoint(subs->stream->chip,
 552						   alts, fmt->endpoint, subs->direction,
 553						   SND_USB_ENDPOINT_TYPE_DATA);
 554
 555	if (!subs->data_endpoint)
 556		return -EINVAL;
 557
 558	err = set_sync_endpoint(subs, fmt, dev, alts, altsd);
 559	if (err < 0)
 560		return err;
 561
 562	err = snd_usb_init_pitch(subs->stream->chip, fmt->iface, alts, fmt);
 563	if (err < 0)
 564		return err;
 565
 566	subs->cur_audiofmt = fmt;
 567
 568	snd_usb_set_format_quirk(subs, fmt);
 569
 570	return 0;
 571}
 572
 573/*
 574 * Return the score of matching two audioformats.
 575 * Veto the audioformat if:
 576 * - It has no channels for some reason.
 577 * - Requested PCM format is not supported.
 578 * - Requested sample rate is not supported.
 579 */
 580static int match_endpoint_audioformats(struct snd_usb_substream *subs,
 581				       struct audioformat *fp,
 582				       struct audioformat *match, int rate,
 583				       snd_pcm_format_t pcm_format)
 584{
 585	int i;
 586	int score = 0;
 587
 588	if (fp->channels < 1) {
 589		dev_dbg(&subs->dev->dev,
 590			"%s: (fmt @%p) no channels\n", __func__, fp);
 591		return 0;
 592	}
 593
 594	if (!(fp->formats & pcm_format_to_bits(pcm_format))) {
 595		dev_dbg(&subs->dev->dev,
 596			"%s: (fmt @%p) no match for format %d\n", __func__,
 597			fp, pcm_format);
 598		return 0;
 599	}
 600
 601	for (i = 0; i < fp->nr_rates; i++) {
 602		if (fp->rate_table[i] == rate) {
 603			score++;
 604			break;
 605		}
 606	}
 607	if (!score) {
 608		dev_dbg(&subs->dev->dev,
 609			"%s: (fmt @%p) no match for rate %d\n", __func__,
 610			fp, rate);
 611		return 0;
 612	}
 613
 614	if (fp->channels == match->channels)
 615		score++;
 616
 617	dev_dbg(&subs->dev->dev,
 618		"%s: (fmt @%p) score %d\n", __func__, fp, score);
 619
 620	return score;
 621}
 622
 623/*
 624 * Configure the sync ep using the rate and pcm format of the data ep.
 625 */
 626static int configure_sync_endpoint(struct snd_usb_substream *subs)
 627{
 628	int ret;
 629	struct audioformat *fp;
 630	struct audioformat *sync_fp = NULL;
 631	int cur_score = 0;
 632	int sync_period_bytes = subs->period_bytes;
 633	struct snd_usb_substream *sync_subs =
 634		&subs->stream->substream[subs->direction ^ 1];
 635
 636	if (subs->sync_endpoint->type != SND_USB_ENDPOINT_TYPE_DATA ||
 637	    !subs->stream)
 638		return snd_usb_endpoint_set_params(subs->sync_endpoint,
 639						   subs->pcm_format,
 640						   subs->channels,
 641						   subs->period_bytes,
 642						   0, 0,
 643						   subs->cur_rate,
 644						   subs->cur_audiofmt,
 645						   NULL);
 646
 647	/* Try to find the best matching audioformat. */
 648	list_for_each_entry(fp, &sync_subs->fmt_list, list) {
 649		int score = match_endpoint_audioformats(subs,
 650							fp, subs->cur_audiofmt,
 651			subs->cur_rate, subs->pcm_format);
 652
 653		if (score > cur_score) {
 654			sync_fp = fp;
 655			cur_score = score;
 656		}
 657	}
 658
 659	if (unlikely(sync_fp == NULL)) {
 660		dev_err(&subs->dev->dev,
 661			"%s: no valid audioformat for sync ep %x found\n",
 662			__func__, sync_subs->ep_num);
 663		return -EINVAL;
 664	}
 665
 666	/*
 667	 * Recalculate the period bytes if channel number differ between
 668	 * data and sync ep audioformat.
 669	 */
 670	if (sync_fp->channels != subs->channels) {
 671		sync_period_bytes = (subs->period_bytes / subs->channels) *
 672			sync_fp->channels;
 673		dev_dbg(&subs->dev->dev,
 674			"%s: adjusted sync ep period bytes (%d -> %d)\n",
 675			__func__, subs->period_bytes, sync_period_bytes);
 676	}
 677
 678	ret = snd_usb_endpoint_set_params(subs->sync_endpoint,
 679					  subs->pcm_format,
 680					  sync_fp->channels,
 681					  sync_period_bytes,
 682					  0, 0,
 683					  subs->cur_rate,
 684					  sync_fp,
 685					  NULL);
 686
 687	return ret;
 688}
 689
 690/*
 691 * configure endpoint params
 692 *
 693 * called  during initial setup and upon resume
 694 */
 695static int configure_endpoint(struct snd_usb_substream *subs)
 696{
 697	int ret;
 698
 699	/* format changed */
 700	stop_endpoints(subs, true);
 
 701	ret = snd_usb_endpoint_set_params(subs->data_endpoint,
 702					  subs->pcm_format,
 703					  subs->channels,
 704					  subs->period_bytes,
 705					  subs->period_frames,
 706					  subs->buffer_periods,
 707					  subs->cur_rate,
 708					  subs->cur_audiofmt,
 709					  subs->sync_endpoint);
 710	if (ret < 0)
 711		return ret;
 712
 713	if (subs->sync_endpoint)
 714		ret = configure_sync_endpoint(subs);
 715
 716	return ret;
 717}
 718
 719static int snd_usb_pcm_change_state(struct snd_usb_substream *subs, int state)
 720{
 721	int ret;
 722
 723	if (!subs->str_pd)
 724		return 0;
 725
 726	ret = snd_usb_power_domain_set(subs->stream->chip, subs->str_pd, state);
 727	if (ret < 0) {
 728		dev_err(&subs->dev->dev,
 729			"Cannot change Power Domain ID: %d to state: %d. Err: %d\n",
 730			subs->str_pd->pd_id, state, ret);
 731		return ret;
 732	}
 733
 734	return 0;
 735}
 736
 737int snd_usb_pcm_suspend(struct snd_usb_stream *as)
 738{
 739	int ret;
 740
 741	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D2);
 742	if (ret < 0)
 743		return ret;
 744
 745	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D2);
 746	if (ret < 0)
 747		return ret;
 748
 749	return 0;
 750}
 751
 752int snd_usb_pcm_resume(struct snd_usb_stream *as)
 753{
 754	int ret;
 755
 756	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D1);
 757	if (ret < 0)
 758		return ret;
 759
 760	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D1);
 761	if (ret < 0)
 762		return ret;
 763
 764	return 0;
 765}
 766
 767/*
 768 * hw_params callback
 769 *
 770 * allocate a buffer and set the given audio format.
 771 *
 772 * so far we use a physically linear buffer although packetize transfer
 773 * doesn't need a continuous area.
 774 * if sg buffer is supported on the later version of alsa, we'll follow
 775 * that.
 776 */
 777static int snd_usb_hw_params(struct snd_pcm_substream *substream,
 778			     struct snd_pcm_hw_params *hw_params)
 779{
 780	struct snd_usb_substream *subs = substream->runtime->private_data;
 781	struct audioformat *fmt;
 782	int ret;
 783
 784	ret = snd_media_start_pipeline(subs);
 785	if (ret)
 786		return ret;
 787
 788	if (snd_usb_use_vmalloc)
 789		ret = snd_pcm_lib_alloc_vmalloc_buffer(substream,
 790						       params_buffer_bytes(hw_params));
 791	else
 792		ret = snd_pcm_lib_malloc_pages(substream,
 793					       params_buffer_bytes(hw_params));
 794	if (ret < 0)
 795		goto stop_pipeline;
 796
 797	subs->pcm_format = params_format(hw_params);
 798	subs->period_bytes = params_period_bytes(hw_params);
 799	subs->period_frames = params_period_size(hw_params);
 800	subs->buffer_periods = params_periods(hw_params);
 801	subs->channels = params_channels(hw_params);
 802	subs->cur_rate = params_rate(hw_params);
 803
 804	fmt = find_format(subs);
 805	if (!fmt) {
 806		dev_dbg(&subs->dev->dev,
 807			"cannot set format: format = %#x, rate = %d, channels = %d\n",
 808			   subs->pcm_format, subs->cur_rate, subs->channels);
 809		ret = -EINVAL;
 810		goto stop_pipeline;
 811	}
 812
 813	ret = snd_usb_lock_shutdown(subs->stream->chip);
 814	if (ret < 0)
 815		goto stop_pipeline;
 816
 817	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
 818	if (ret < 0)
 819		goto unlock;
 820
 821	ret = set_format(subs, fmt);
 822	if (ret < 0)
 823		goto unlock;
 824
 825	subs->interface = fmt->iface;
 826	subs->altset_idx = fmt->altset_idx;
 827	subs->need_setup_ep = true;
 828
 829 unlock:
 830	snd_usb_unlock_shutdown(subs->stream->chip);
 831	if (ret < 0)
 832		goto stop_pipeline;
 833	return ret;
 834
 835 stop_pipeline:
 836	snd_media_stop_pipeline(subs);
 837	return ret;
 838}
 839
 840/*
 841 * hw_free callback
 842 *
 843 * reset the audio format and release the buffer
 844 */
 845static int snd_usb_hw_free(struct snd_pcm_substream *substream)
 846{
 847	struct snd_usb_substream *subs = substream->runtime->private_data;
 848
 849	snd_media_stop_pipeline(subs);
 850	subs->cur_audiofmt = NULL;
 851	subs->cur_rate = 0;
 852	subs->period_bytes = 0;
 853	if (!snd_usb_lock_shutdown(subs->stream->chip)) {
 854		stop_endpoints(subs, true);
 
 855		snd_usb_endpoint_deactivate(subs->sync_endpoint);
 856		snd_usb_endpoint_deactivate(subs->data_endpoint);
 857		snd_usb_unlock_shutdown(subs->stream->chip);
 858	}
 859
 860	if (snd_usb_use_vmalloc)
 861		return snd_pcm_lib_free_vmalloc_buffer(substream);
 862	else
 863		return snd_pcm_lib_free_pages(substream);
 864}
 865
 866/*
 867 * prepare callback
 868 *
 869 * only a few subtle things...
 870 */
 871static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
 872{
 873	struct snd_pcm_runtime *runtime = substream->runtime;
 874	struct snd_usb_substream *subs = runtime->private_data;
 875	struct usb_host_interface *alts;
 876	struct usb_interface *iface;
 877	int ret;
 878
 879	if (! subs->cur_audiofmt) {
 880		dev_err(&subs->dev->dev, "no format is specified!\n");
 881		return -ENXIO;
 882	}
 883
 884	ret = snd_usb_lock_shutdown(subs->stream->chip);
 885	if (ret < 0)
 886		return ret;
 887	if (snd_BUG_ON(!subs->data_endpoint)) {
 888		ret = -EIO;
 889		goto unlock;
 890	}
 891
 892	snd_usb_endpoint_sync_pending_stop(subs->sync_endpoint);
 893	snd_usb_endpoint_sync_pending_stop(subs->data_endpoint);
 894
 895	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
 896	if (ret < 0)
 897		goto unlock;
 898
 899	ret = set_format(subs, subs->cur_audiofmt);
 900	if (ret < 0)
 901		goto unlock;
 902
 903	if (subs->need_setup_ep) {
 904
 905		iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
 906		alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
 907		ret = snd_usb_init_sample_rate(subs->stream->chip,
 908					       subs->cur_audiofmt->iface,
 909					       alts,
 910					       subs->cur_audiofmt,
 911					       subs->cur_rate);
 912		if (ret < 0)
 913			goto unlock;
 914
 915		ret = configure_endpoint(subs);
 916		if (ret < 0)
 917			goto unlock;
 918		subs->need_setup_ep = false;
 919	}
 920
 921	/* some unit conversions in runtime */
 922	subs->data_endpoint->maxframesize =
 923		bytes_to_frames(runtime, subs->data_endpoint->maxpacksize);
 924	subs->data_endpoint->curframesize =
 925		bytes_to_frames(runtime, subs->data_endpoint->curpacksize);
 926
 927	/* reset the pointer */
 928	subs->hwptr_done = 0;
 929	subs->transfer_done = 0;
 930	subs->last_delay = 0;
 931	subs->last_frame_number = 0;
 932	runtime->delay = 0;
 933
 934	/* for playback, submit the URBs now; otherwise, the first hwptr_done
 935	 * updates for all URBs would happen at the same time when starting */
 936	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK)
 937		ret = start_endpoints(subs);
 938
 939 unlock:
 940	snd_usb_unlock_shutdown(subs->stream->chip);
 941	return ret;
 942}
 943
 944static const struct snd_pcm_hardware snd_usb_hardware =
 945{
 946	.info =			SNDRV_PCM_INFO_MMAP |
 947				SNDRV_PCM_INFO_MMAP_VALID |
 948				SNDRV_PCM_INFO_BATCH |
 949				SNDRV_PCM_INFO_INTERLEAVED |
 950				SNDRV_PCM_INFO_BLOCK_TRANSFER |
 951				SNDRV_PCM_INFO_PAUSE,
 952	.buffer_bytes_max =	1024 * 1024,
 953	.period_bytes_min =	64,
 954	.period_bytes_max =	512 * 1024,
 955	.periods_min =		2,
 956	.periods_max =		1024,
 957};
 958
 959static int hw_check_valid_format(struct snd_usb_substream *subs,
 960				 struct snd_pcm_hw_params *params,
 961				 struct audioformat *fp)
 962{
 963	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
 964	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
 965	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
 966	struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
 967	struct snd_mask check_fmts;
 968	unsigned int ptime;
 969
 970	/* check the format */
 971	snd_mask_none(&check_fmts);
 972	check_fmts.bits[0] = (u32)fp->formats;
 973	check_fmts.bits[1] = (u32)(fp->formats >> 32);
 974	snd_mask_intersect(&check_fmts, fmts);
 975	if (snd_mask_empty(&check_fmts)) {
 976		hwc_debug("   > check: no supported format %d\n", fp->format);
 977		return 0;
 978	}
 979	/* check the channels */
 980	if (fp->channels < ct->min || fp->channels > ct->max) {
 981		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
 982		return 0;
 983	}
 984	/* check the rate is within the range */
 985	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
 986		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
 987		return 0;
 988	}
 989	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
 990		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
 991		return 0;
 992	}
 993	/* check whether the period time is >= the data packet interval */
 994	if (subs->speed != USB_SPEED_FULL) {
 995		ptime = 125 * (1 << fp->datainterval);
 996		if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
 997			hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
 998			return 0;
 999		}
1000	}
1001	return 1;
1002}
1003
1004static int hw_rule_rate(struct snd_pcm_hw_params *params,
1005			struct snd_pcm_hw_rule *rule)
1006{
1007	struct snd_usb_substream *subs = rule->private;
1008	struct audioformat *fp;
1009	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
1010	unsigned int rmin, rmax;
1011	int changed;
1012
1013	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
1014	changed = 0;
1015	rmin = rmax = 0;
1016	list_for_each_entry(fp, &subs->fmt_list, list) {
1017		if (!hw_check_valid_format(subs, params, fp))
1018			continue;
1019		if (changed++) {
1020			if (rmin > fp->rate_min)
1021				rmin = fp->rate_min;
1022			if (rmax < fp->rate_max)
1023				rmax = fp->rate_max;
1024		} else {
1025			rmin = fp->rate_min;
1026			rmax = fp->rate_max;
1027		}
1028	}
1029
1030	if (!changed) {
1031		hwc_debug("  --> get empty\n");
1032		it->empty = 1;
1033		return -EINVAL;
1034	}
1035
1036	changed = 0;
1037	if (it->min < rmin) {
1038		it->min = rmin;
1039		it->openmin = 0;
1040		changed = 1;
1041	}
1042	if (it->max > rmax) {
1043		it->max = rmax;
1044		it->openmax = 0;
1045		changed = 1;
1046	}
1047	if (snd_interval_checkempty(it)) {
1048		it->empty = 1;
1049		return -EINVAL;
1050	}
1051	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
1052	return changed;
1053}
1054
1055
1056static int hw_rule_channels(struct snd_pcm_hw_params *params,
1057			    struct snd_pcm_hw_rule *rule)
1058{
1059	struct snd_usb_substream *subs = rule->private;
1060	struct audioformat *fp;
1061	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
1062	unsigned int rmin, rmax;
1063	int changed;
1064
1065	hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
1066	changed = 0;
1067	rmin = rmax = 0;
1068	list_for_each_entry(fp, &subs->fmt_list, list) {
1069		if (!hw_check_valid_format(subs, params, fp))
1070			continue;
1071		if (changed++) {
1072			if (rmin > fp->channels)
1073				rmin = fp->channels;
1074			if (rmax < fp->channels)
1075				rmax = fp->channels;
1076		} else {
1077			rmin = fp->channels;
1078			rmax = fp->channels;
1079		}
1080	}
1081
1082	if (!changed) {
1083		hwc_debug("  --> get empty\n");
1084		it->empty = 1;
1085		return -EINVAL;
1086	}
1087
1088	changed = 0;
1089	if (it->min < rmin) {
1090		it->min = rmin;
1091		it->openmin = 0;
1092		changed = 1;
1093	}
1094	if (it->max > rmax) {
1095		it->max = rmax;
1096		it->openmax = 0;
1097		changed = 1;
1098	}
1099	if (snd_interval_checkempty(it)) {
1100		it->empty = 1;
1101		return -EINVAL;
1102	}
1103	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
1104	return changed;
1105}
1106
1107static int hw_rule_format(struct snd_pcm_hw_params *params,
1108			  struct snd_pcm_hw_rule *rule)
1109{
1110	struct snd_usb_substream *subs = rule->private;
1111	struct audioformat *fp;
1112	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
1113	u64 fbits;
1114	u32 oldbits[2];
1115	int changed;
1116
1117	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
1118	fbits = 0;
1119	list_for_each_entry(fp, &subs->fmt_list, list) {
1120		if (!hw_check_valid_format(subs, params, fp))
1121			continue;
1122		fbits |= fp->formats;
1123	}
1124
1125	oldbits[0] = fmt->bits[0];
1126	oldbits[1] = fmt->bits[1];
1127	fmt->bits[0] &= (u32)fbits;
1128	fmt->bits[1] &= (u32)(fbits >> 32);
1129	if (!fmt->bits[0] && !fmt->bits[1]) {
1130		hwc_debug("  --> get empty\n");
1131		return -EINVAL;
1132	}
1133	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
1134	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
1135	return changed;
1136}
1137
1138static int hw_rule_period_time(struct snd_pcm_hw_params *params,
1139			       struct snd_pcm_hw_rule *rule)
1140{
1141	struct snd_usb_substream *subs = rule->private;
1142	struct audioformat *fp;
1143	struct snd_interval *it;
1144	unsigned char min_datainterval;
1145	unsigned int pmin;
1146	int changed;
1147
1148	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
1149	hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
1150	min_datainterval = 0xff;
1151	list_for_each_entry(fp, &subs->fmt_list, list) {
1152		if (!hw_check_valid_format(subs, params, fp))
1153			continue;
1154		min_datainterval = min(min_datainterval, fp->datainterval);
1155	}
1156	if (min_datainterval == 0xff) {
1157		hwc_debug("  --> get empty\n");
1158		it->empty = 1;
1159		return -EINVAL;
1160	}
1161	pmin = 125 * (1 << min_datainterval);
1162	changed = 0;
1163	if (it->min < pmin) {
1164		it->min = pmin;
1165		it->openmin = 0;
1166		changed = 1;
1167	}
1168	if (snd_interval_checkempty(it)) {
1169		it->empty = 1;
1170		return -EINVAL;
1171	}
1172	hwc_debug("  --> (%u,%u) (changed = %d)\n", it->min, it->max, changed);
1173	return changed;
1174}
1175
1176/*
1177 *  If the device supports unusual bit rates, does the request meet these?
1178 */
1179static int snd_usb_pcm_check_knot(struct snd_pcm_runtime *runtime,
1180				  struct snd_usb_substream *subs)
1181{
1182	struct audioformat *fp;
1183	int *rate_list;
1184	int count = 0, needs_knot = 0;
1185	int err;
1186
1187	kfree(subs->rate_list.list);
1188	subs->rate_list.list = NULL;
1189
1190	list_for_each_entry(fp, &subs->fmt_list, list) {
1191		if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)
1192			return 0;
1193		count += fp->nr_rates;
1194		if (fp->rates & SNDRV_PCM_RATE_KNOT)
1195			needs_knot = 1;
1196	}
1197	if (!needs_knot)
1198		return 0;
1199
1200	subs->rate_list.list = rate_list =
1201		kmalloc_array(count, sizeof(int), GFP_KERNEL);
1202	if (!subs->rate_list.list)
1203		return -ENOMEM;
1204	subs->rate_list.count = count;
1205	subs->rate_list.mask = 0;
1206	count = 0;
1207	list_for_each_entry(fp, &subs->fmt_list, list) {
1208		int i;
1209		for (i = 0; i < fp->nr_rates; i++)
1210			rate_list[count++] = fp->rate_table[i];
1211	}
1212	err = snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1213					 &subs->rate_list);
1214	if (err < 0)
1215		return err;
1216
1217	return 0;
1218}
1219
1220
1221/*
1222 * set up the runtime hardware information.
1223 */
1224
1225static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
1226{
1227	struct audioformat *fp;
1228	unsigned int pt, ptmin;
1229	int param_period_time_if_needed;
1230	int err;
1231
1232	runtime->hw.formats = subs->formats;
1233
1234	runtime->hw.rate_min = 0x7fffffff;
1235	runtime->hw.rate_max = 0;
1236	runtime->hw.channels_min = 256;
1237	runtime->hw.channels_max = 0;
1238	runtime->hw.rates = 0;
1239	ptmin = UINT_MAX;
1240	/* check min/max rates and channels */
1241	list_for_each_entry(fp, &subs->fmt_list, list) {
1242		runtime->hw.rates |= fp->rates;
1243		if (runtime->hw.rate_min > fp->rate_min)
1244			runtime->hw.rate_min = fp->rate_min;
1245		if (runtime->hw.rate_max < fp->rate_max)
1246			runtime->hw.rate_max = fp->rate_max;
1247		if (runtime->hw.channels_min > fp->channels)
1248			runtime->hw.channels_min = fp->channels;
1249		if (runtime->hw.channels_max < fp->channels)
1250			runtime->hw.channels_max = fp->channels;
1251		if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
1252			/* FIXME: there might be more than one audio formats... */
1253			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
1254				fp->frame_size;
1255		}
1256		pt = 125 * (1 << fp->datainterval);
1257		ptmin = min(ptmin, pt);
1258	}
1259
1260	param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
1261	if (subs->speed == USB_SPEED_FULL)
1262		/* full speed devices have fixed data packet interval */
1263		ptmin = 1000;
1264	if (ptmin == 1000)
1265		/* if period time doesn't go below 1 ms, no rules needed */
1266		param_period_time_if_needed = -1;
1267
1268	err = snd_pcm_hw_constraint_minmax(runtime,
1269					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1270					   ptmin, UINT_MAX);
1271	if (err < 0)
1272		return err;
1273
1274	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1275				  hw_rule_rate, subs,
1276				  SNDRV_PCM_HW_PARAM_FORMAT,
1277				  SNDRV_PCM_HW_PARAM_CHANNELS,
1278				  param_period_time_if_needed,
1279				  -1);
1280	if (err < 0)
1281		return err;
1282	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
1283				  hw_rule_channels, subs,
1284				  SNDRV_PCM_HW_PARAM_FORMAT,
1285				  SNDRV_PCM_HW_PARAM_RATE,
1286				  param_period_time_if_needed,
1287				  -1);
1288	if (err < 0)
1289		return err;
1290	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1291				  hw_rule_format, subs,
1292				  SNDRV_PCM_HW_PARAM_RATE,
1293				  SNDRV_PCM_HW_PARAM_CHANNELS,
1294				  param_period_time_if_needed,
1295				  -1);
1296	if (err < 0)
1297		return err;
1298	if (param_period_time_if_needed >= 0) {
1299		err = snd_pcm_hw_rule_add(runtime, 0,
1300					  SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1301					  hw_rule_period_time, subs,
1302					  SNDRV_PCM_HW_PARAM_FORMAT,
1303					  SNDRV_PCM_HW_PARAM_CHANNELS,
1304					  SNDRV_PCM_HW_PARAM_RATE,
1305					  -1);
1306		if (err < 0)
1307			return err;
1308	}
1309	err = snd_usb_pcm_check_knot(runtime, subs);
1310	if (err < 0)
1311		return err;
1312
1313	return snd_usb_autoresume(subs->stream->chip);
1314}
1315
1316static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
1317{
1318	int direction = substream->stream;
1319	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1320	struct snd_pcm_runtime *runtime = substream->runtime;
1321	struct snd_usb_substream *subs = &as->substream[direction];
1322	int ret;
1323
1324	subs->interface = -1;
1325	subs->altset_idx = 0;
1326	runtime->hw = snd_usb_hardware;
1327	runtime->private_data = subs;
1328	subs->pcm_substream = substream;
1329	/* runtime PM is also done there */
1330
1331	/* initialize DSD/DOP context */
1332	subs->dsd_dop.byte_idx = 0;
1333	subs->dsd_dop.channel = 0;
1334	subs->dsd_dop.marker = 1;
1335
1336	ret = setup_hw_info(runtime, subs);
1337	if (ret == 0) {
1338		ret = snd_media_stream_init(subs, as->pcm, direction);
1339		if (ret)
1340			snd_usb_autosuspend(subs->stream->chip);
1341	}
1342	return ret;
1343}
1344
1345static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
1346{
1347	int direction = substream->stream;
1348	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1349	struct snd_usb_substream *subs = &as->substream[direction];
1350	int ret;
1351
1352	stop_endpoints(subs, true);
1353	snd_media_stop_pipeline(subs);
1354
1355	if (!as->chip->keep_iface &&
1356	    subs->interface >= 0 &&
1357	    !snd_usb_lock_shutdown(subs->stream->chip)) {
1358		usb_set_interface(subs->dev, subs->interface, 0);
1359		subs->interface = -1;
1360		ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
1361		snd_usb_unlock_shutdown(subs->stream->chip);
1362		if (ret < 0)
1363			return ret;
1364	}
1365
1366	subs->pcm_substream = NULL;
1367	snd_usb_autosuspend(subs->stream->chip);
1368
1369	return 0;
1370}
1371
1372/* Since a URB can handle only a single linear buffer, we must use double
1373 * buffering when the data to be transferred overflows the buffer boundary.
1374 * To avoid inconsistencies when updating hwptr_done, we use double buffering
1375 * for all URBs.
1376 */
1377static void retire_capture_urb(struct snd_usb_substream *subs,
1378			       struct urb *urb)
1379{
1380	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1381	unsigned int stride, frames, bytes, oldptr;
1382	int i, period_elapsed = 0;
1383	unsigned long flags;
1384	unsigned char *cp;
1385	int current_frame_number;
1386
1387	/* read frame number here, update pointer in critical section */
1388	current_frame_number = usb_get_current_frame_number(subs->dev);
1389
1390	stride = runtime->frame_bits >> 3;
1391
1392	for (i = 0; i < urb->number_of_packets; i++) {
1393		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;
1394		if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
1395			dev_dbg(&subs->dev->dev, "frame %d active: %d\n",
1396				i, urb->iso_frame_desc[i].status);
1397			// continue;
1398		}
1399		bytes = urb->iso_frame_desc[i].actual_length;
 
 
 
 
 
 
1400		frames = bytes / stride;
1401		if (!subs->txfr_quirk)
1402			bytes = frames * stride;
1403		if (bytes % (runtime->sample_bits >> 3) != 0) {
1404			int oldbytes = bytes;
1405			bytes = frames * stride;
1406			dev_warn_ratelimited(&subs->dev->dev,
1407				 "Corrected urb data len. %d->%d\n",
1408							oldbytes, bytes);
1409		}
1410		/* update the current pointer */
1411		spin_lock_irqsave(&subs->lock, flags);
1412		oldptr = subs->hwptr_done;
1413		subs->hwptr_done += bytes;
1414		if (subs->hwptr_done >= runtime->buffer_size * stride)
1415			subs->hwptr_done -= runtime->buffer_size * stride;
1416		frames = (bytes + (oldptr % stride)) / stride;
1417		subs->transfer_done += frames;
1418		if (subs->transfer_done >= runtime->period_size) {
1419			subs->transfer_done -= runtime->period_size;
1420			period_elapsed = 1;
1421		}
1422		/* capture delay is by construction limited to one URB,
1423		 * reset delays here
1424		 */
1425		runtime->delay = subs->last_delay = 0;
1426
1427		/* realign last_frame_number */
1428		subs->last_frame_number = current_frame_number;
1429		subs->last_frame_number &= 0xFF; /* keep 8 LSBs */
1430
1431		spin_unlock_irqrestore(&subs->lock, flags);
1432		/* copy a data chunk */
1433		if (oldptr + bytes > runtime->buffer_size * stride) {
1434			unsigned int bytes1 =
1435					runtime->buffer_size * stride - oldptr;
1436			memcpy(runtime->dma_area + oldptr, cp, bytes1);
1437			memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
1438		} else {
1439			memcpy(runtime->dma_area + oldptr, cp, bytes);
1440		}
1441	}
1442
1443	if (period_elapsed)
1444		snd_pcm_period_elapsed(subs->pcm_substream);
1445}
1446
1447static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
1448					     struct urb *urb, unsigned int bytes)
1449{
1450	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1451	unsigned int stride = runtime->frame_bits >> 3;
1452	unsigned int dst_idx = 0;
1453	unsigned int src_idx = subs->hwptr_done;
1454	unsigned int wrap = runtime->buffer_size * stride;
1455	u8 *dst = urb->transfer_buffer;
1456	u8 *src = runtime->dma_area;
1457	u8 marker[] = { 0x05, 0xfa };
1458
1459	/*
1460	 * The DSP DOP format defines a way to transport DSD samples over
1461	 * normal PCM data endpoints. It requires stuffing of marker bytes
1462	 * (0x05 and 0xfa, alternating per sample frame), and then expects
1463	 * 2 additional bytes of actual payload. The whole frame is stored
1464	 * LSB.
1465	 *
1466	 * Hence, for a stereo transport, the buffer layout looks like this,
1467	 * where L refers to left channel samples and R to right.
1468	 *
1469	 *   L1 L2 0x05   R1 R2 0x05   L3 L4 0xfa  R3 R4 0xfa
1470	 *   L5 L6 0x05   R5 R6 0x05   L7 L8 0xfa  R7 R8 0xfa
1471	 *   .....
1472	 *
1473	 */
1474
1475	while (bytes--) {
1476		if (++subs->dsd_dop.byte_idx == 3) {
1477			/* frame boundary? */
1478			dst[dst_idx++] = marker[subs->dsd_dop.marker];
1479			src_idx += 2;
1480			subs->dsd_dop.byte_idx = 0;
1481
1482			if (++subs->dsd_dop.channel % runtime->channels == 0) {
1483				/* alternate the marker */
1484				subs->dsd_dop.marker++;
1485				subs->dsd_dop.marker %= ARRAY_SIZE(marker);
1486				subs->dsd_dop.channel = 0;
1487			}
1488		} else {
1489			/* stuff the DSD payload */
1490			int idx = (src_idx + subs->dsd_dop.byte_idx - 1) % wrap;
1491
1492			if (subs->cur_audiofmt->dsd_bitrev)
1493				dst[dst_idx++] = bitrev8(src[idx]);
1494			else
1495				dst[dst_idx++] = src[idx];
1496
1497			subs->hwptr_done++;
1498		}
1499	}
1500	if (subs->hwptr_done >= runtime->buffer_size * stride)
1501		subs->hwptr_done -= runtime->buffer_size * stride;
1502}
1503
1504static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
1505			int offset, int stride, unsigned int bytes)
1506{
1507	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1508
1509	if (subs->hwptr_done + bytes > runtime->buffer_size * stride) {
1510		/* err, the transferred area goes over buffer boundary. */
1511		unsigned int bytes1 =
1512			runtime->buffer_size * stride - subs->hwptr_done;
1513		memcpy(urb->transfer_buffer + offset,
1514		       runtime->dma_area + subs->hwptr_done, bytes1);
1515		memcpy(urb->transfer_buffer + offset + bytes1,
1516		       runtime->dma_area, bytes - bytes1);
1517	} else {
1518		memcpy(urb->transfer_buffer + offset,
1519		       runtime->dma_area + subs->hwptr_done, bytes);
1520	}
1521	subs->hwptr_done += bytes;
1522	if (subs->hwptr_done >= runtime->buffer_size * stride)
1523		subs->hwptr_done -= runtime->buffer_size * stride;
1524}
1525
1526static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
1527				      struct urb *urb, int stride,
1528				      unsigned int bytes)
1529{
1530	__le32 packet_length;
1531	int i;
1532
1533	/* Put __le32 length descriptor at start of each packet. */
1534	for (i = 0; i < urb->number_of_packets; i++) {
1535		unsigned int length = urb->iso_frame_desc[i].length;
1536		unsigned int offset = urb->iso_frame_desc[i].offset;
1537
1538		packet_length = cpu_to_le32(length);
1539		offset += i * sizeof(packet_length);
1540		urb->iso_frame_desc[i].offset = offset;
1541		urb->iso_frame_desc[i].length += sizeof(packet_length);
1542		memcpy(urb->transfer_buffer + offset,
1543		       &packet_length, sizeof(packet_length));
1544		copy_to_urb(subs, urb, offset + sizeof(packet_length),
1545			    stride, length);
1546	}
1547	/* Adjust transfer size accordingly. */
1548	bytes += urb->number_of_packets * sizeof(packet_length);
1549	return bytes;
1550}
1551
1552static void prepare_playback_urb(struct snd_usb_substream *subs,
1553				 struct urb *urb)
1554{
1555	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1556	struct snd_usb_endpoint *ep = subs->data_endpoint;
1557	struct snd_urb_ctx *ctx = urb->context;
1558	unsigned int counts, frames, bytes;
1559	int i, stride, period_elapsed = 0;
1560	unsigned long flags;
1561
1562	stride = runtime->frame_bits >> 3;
1563
1564	frames = 0;
1565	urb->number_of_packets = 0;
1566	spin_lock_irqsave(&subs->lock, flags);
1567	subs->frame_limit += ep->max_urb_frames;
1568	for (i = 0; i < ctx->packets; i++) {
1569		if (ctx->packet_size[i])
1570			counts = ctx->packet_size[i];
 
 
1571		else
1572			counts = snd_usb_endpoint_next_packet_size(ep);
1573
1574		/* set up descriptor */
1575		urb->iso_frame_desc[i].offset = frames * ep->stride;
1576		urb->iso_frame_desc[i].length = counts * ep->stride;
1577		frames += counts;
1578		urb->number_of_packets++;
1579		subs->transfer_done += counts;
1580		if (subs->transfer_done >= runtime->period_size) {
1581			subs->transfer_done -= runtime->period_size;
1582			subs->frame_limit = 0;
1583			period_elapsed = 1;
1584			if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
1585				if (subs->transfer_done > 0) {
1586					/* FIXME: fill-max mode is not
1587					 * supported yet */
1588					frames -= subs->transfer_done;
1589					counts -= subs->transfer_done;
1590					urb->iso_frame_desc[i].length =
1591						counts * ep->stride;
1592					subs->transfer_done = 0;
1593				}
1594				i++;
1595				if (i < ctx->packets) {
1596					/* add a transfer delimiter */
1597					urb->iso_frame_desc[i].offset =
1598						frames * ep->stride;
1599					urb->iso_frame_desc[i].length = 0;
1600					urb->number_of_packets++;
1601				}
1602				break;
1603			}
1604		}
1605		/* finish at the period boundary or after enough frames */
1606		if ((period_elapsed ||
1607				subs->transfer_done >= subs->frame_limit) &&
1608		    !snd_usb_endpoint_implicit_feedback_sink(ep))
1609			break;
1610	}
1611	bytes = frames * ep->stride;
1612
1613	if (unlikely(subs->pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
1614		     subs->cur_audiofmt->dsd_dop)) {
1615		fill_playback_urb_dsd_dop(subs, urb, bytes);
1616	} else if (unlikely(subs->pcm_format == SNDRV_PCM_FORMAT_DSD_U8 &&
1617			   subs->cur_audiofmt->dsd_bitrev)) {
1618		/* bit-reverse the bytes */
1619		u8 *buf = urb->transfer_buffer;
1620		for (i = 0; i < bytes; i++) {
1621			int idx = (subs->hwptr_done + i)
1622				% (runtime->buffer_size * stride);
1623			buf[i] = bitrev8(runtime->dma_area[idx]);
1624		}
1625
1626		subs->hwptr_done += bytes;
1627		if (subs->hwptr_done >= runtime->buffer_size * stride)
1628			subs->hwptr_done -= runtime->buffer_size * stride;
1629	} else {
1630		/* usual PCM */
1631		if (!subs->tx_length_quirk)
1632			copy_to_urb(subs, urb, 0, stride, bytes);
1633		else
1634			bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
1635			/* bytes is now amount of outgoing data */
1636	}
1637
1638	/* update delay with exact number of samples queued */
1639	runtime->delay = subs->last_delay;
1640	runtime->delay += frames;
1641	subs->last_delay = runtime->delay;
1642
1643	/* realign last_frame_number */
1644	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1645	subs->last_frame_number &= 0xFF; /* keep 8 LSBs */
1646
1647	if (subs->trigger_tstamp_pending_update) {
1648		/* this is the first actual URB submitted,
1649		 * update trigger timestamp to reflect actual start time
1650		 */
1651		snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
1652		subs->trigger_tstamp_pending_update = false;
1653	}
1654
1655	spin_unlock_irqrestore(&subs->lock, flags);
1656	urb->transfer_buffer_length = bytes;
1657	if (period_elapsed)
1658		snd_pcm_period_elapsed(subs->pcm_substream);
1659}
1660
1661/*
1662 * process after playback data complete
1663 * - decrease the delay count again
1664 */
1665static void retire_playback_urb(struct snd_usb_substream *subs,
1666			       struct urb *urb)
1667{
1668	unsigned long flags;
1669	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1670	struct snd_usb_endpoint *ep = subs->data_endpoint;
1671	int processed = urb->transfer_buffer_length / ep->stride;
1672	int est_delay;
1673
1674	/* ignore the delay accounting when procssed=0 is given, i.e.
1675	 * silent payloads are procssed before handling the actual data
1676	 */
1677	if (!processed)
1678		return;
1679
1680	spin_lock_irqsave(&subs->lock, flags);
1681	if (!subs->last_delay)
1682		goto out; /* short path */
1683
1684	est_delay = snd_usb_pcm_delay(subs, runtime->rate);
1685	/* update delay with exact number of samples played */
1686	if (processed > subs->last_delay)
1687		subs->last_delay = 0;
1688	else
1689		subs->last_delay -= processed;
1690	runtime->delay = subs->last_delay;
1691
1692	/*
1693	 * Report when delay estimate is off by more than 2ms.
1694	 * The error should be lower than 2ms since the estimate relies
1695	 * on two reads of a counter updated every ms.
1696	 */
1697	if (abs(est_delay - subs->last_delay) * 1000 > runtime->rate * 2)
1698		dev_dbg_ratelimited(&subs->dev->dev,
1699			"delay: estimated %d, actual %d\n",
1700			est_delay, subs->last_delay);
1701
1702	if (!subs->running) {
1703		/* update last_frame_number for delay counting here since
1704		 * prepare_playback_urb won't be called during pause
1705		 */
1706		subs->last_frame_number =
1707			usb_get_current_frame_number(subs->dev) & 0xff;
1708	}
1709
1710 out:
1711	spin_unlock_irqrestore(&subs->lock, flags);
1712}
1713
1714static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
1715					      int cmd)
1716{
1717	struct snd_usb_substream *subs = substream->runtime->private_data;
1718
1719	switch (cmd) {
1720	case SNDRV_PCM_TRIGGER_START:
1721		subs->trigger_tstamp_pending_update = true;
1722		/* fall through */
1723	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1724		subs->data_endpoint->prepare_data_urb = prepare_playback_urb;
1725		subs->data_endpoint->retire_data_urb = retire_playback_urb;
1726		subs->running = 1;
1727		return 0;
1728	case SNDRV_PCM_TRIGGER_STOP:
1729		stop_endpoints(subs, false);
1730		subs->running = 0;
1731		return 0;
1732	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1733		subs->data_endpoint->prepare_data_urb = NULL;
1734		/* keep retire_data_urb for delay calculation */
1735		subs->data_endpoint->retire_data_urb = retire_playback_urb;
1736		subs->running = 0;
1737		return 0;
 
 
 
 
 
 
 
1738	}
1739
1740	return -EINVAL;
1741}
1742
1743static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
1744					     int cmd)
1745{
1746	int err;
1747	struct snd_usb_substream *subs = substream->runtime->private_data;
1748
1749	switch (cmd) {
1750	case SNDRV_PCM_TRIGGER_START:
1751		err = start_endpoints(subs);
1752		if (err < 0)
1753			return err;
1754
1755		subs->data_endpoint->retire_data_urb = retire_capture_urb;
1756		subs->running = 1;
1757		return 0;
1758	case SNDRV_PCM_TRIGGER_STOP:
1759		stop_endpoints(subs, false);
 
1760		subs->running = 0;
1761		return 0;
1762	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1763		subs->data_endpoint->retire_data_urb = NULL;
1764		subs->running = 0;
1765		return 0;
1766	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1767		subs->data_endpoint->retire_data_urb = retire_capture_urb;
1768		subs->running = 1;
1769		return 0;
 
 
 
 
 
 
 
1770	}
1771
1772	return -EINVAL;
1773}
1774
1775static const struct snd_pcm_ops snd_usb_playback_ops = {
1776	.open =		snd_usb_pcm_open,
1777	.close =	snd_usb_pcm_close,
1778	.ioctl =	snd_pcm_lib_ioctl,
1779	.hw_params =	snd_usb_hw_params,
1780	.hw_free =	snd_usb_hw_free,
1781	.prepare =	snd_usb_pcm_prepare,
1782	.trigger =	snd_usb_substream_playback_trigger,
 
1783	.pointer =	snd_usb_pcm_pointer,
1784	.page =		snd_pcm_lib_get_vmalloc_page,
1785};
1786
1787static const struct snd_pcm_ops snd_usb_capture_ops = {
1788	.open =		snd_usb_pcm_open,
1789	.close =	snd_usb_pcm_close,
1790	.ioctl =	snd_pcm_lib_ioctl,
1791	.hw_params =	snd_usb_hw_params,
1792	.hw_free =	snd_usb_hw_free,
1793	.prepare =	snd_usb_pcm_prepare,
1794	.trigger =	snd_usb_substream_capture_trigger,
1795	.pointer =	snd_usb_pcm_pointer,
1796	.page =		snd_pcm_lib_get_vmalloc_page,
1797};
1798
1799static const struct snd_pcm_ops snd_usb_playback_dev_ops = {
1800	.open =		snd_usb_pcm_open,
1801	.close =	snd_usb_pcm_close,
1802	.ioctl =	snd_pcm_lib_ioctl,
1803	.hw_params =	snd_usb_hw_params,
1804	.hw_free =	snd_usb_hw_free,
1805	.prepare =	snd_usb_pcm_prepare,
1806	.trigger =	snd_usb_substream_playback_trigger,
1807	.pointer =	snd_usb_pcm_pointer,
1808	.page =		snd_pcm_sgbuf_ops_page,
1809};
1810
1811static const struct snd_pcm_ops snd_usb_capture_dev_ops = {
1812	.open =		snd_usb_pcm_open,
1813	.close =	snd_usb_pcm_close,
1814	.ioctl =	snd_pcm_lib_ioctl,
1815	.hw_params =	snd_usb_hw_params,
1816	.hw_free =	snd_usb_hw_free,
1817	.prepare =	snd_usb_pcm_prepare,
1818	.trigger =	snd_usb_substream_capture_trigger,
 
1819	.pointer =	snd_usb_pcm_pointer,
1820	.page =		snd_pcm_sgbuf_ops_page,
1821};
1822
1823void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
1824{
1825	const struct snd_pcm_ops *ops;
1826
1827	if (snd_usb_use_vmalloc)
1828		ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
1829			&snd_usb_playback_ops : &snd_usb_capture_ops;
1830	else
1831		ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
1832			&snd_usb_playback_dev_ops : &snd_usb_capture_dev_ops;
1833	snd_pcm_set_ops(pcm, stream, ops);
1834}
1835
1836void snd_usb_preallocate_buffer(struct snd_usb_substream *subs)
1837{
1838	struct snd_pcm *pcm = subs->stream->pcm;
1839	struct snd_pcm_substream *s = pcm->streams[subs->direction].substream;
1840	struct device *dev = subs->dev->bus->controller;
1841
1842	if (!snd_usb_use_vmalloc)
1843		snd_pcm_lib_preallocate_pages(s, SNDRV_DMA_TYPE_DEV_SG,
1844					      dev, 64*1024, 512*1024);
 
 
 
1845}