xref: /openbmc/linux/sound/usb/pcm.c (revision 35a76585)
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 */
32 snd_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  */
66 static 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  */
84 static 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 
141 static 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 
168 static 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  */
193 int 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 
211 static 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 
263 static void sync_pending_stops(struct snd_usb_substream *subs)
264 {
265 	snd_usb_endpoint_sync_pending_stop(subs->sync_endpoint);
266 	snd_usb_endpoint_sync_pending_stop(subs->data_endpoint);
267 }
268 
269 static void stop_endpoints(struct snd_usb_substream *subs)
270 {
271 	if (test_and_clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags))
272 		snd_usb_endpoint_stop(subs->sync_endpoint);
273 
274 	if (test_and_clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags))
275 		snd_usb_endpoint_stop(subs->data_endpoint);
276 }
277 
278 /* PCM sync_stop callback */
279 static int snd_usb_pcm_sync_stop(struct snd_pcm_substream *substream)
280 {
281 	struct snd_usb_substream *subs = substream->runtime->private_data;
282 
283 	if (!snd_usb_lock_shutdown(subs->stream->chip)) {
284 		sync_pending_stops(subs);
285 		snd_usb_unlock_shutdown(subs->stream->chip);
286 	}
287 	return 0;
288 }
289 
290 static int search_roland_implicit_fb(struct usb_device *dev, int ifnum,
291 				     unsigned int altsetting,
292 				     struct usb_host_interface **alts,
293 				     unsigned int *ep)
294 {
295 	struct usb_interface *iface;
296 	struct usb_interface_descriptor *altsd;
297 	struct usb_endpoint_descriptor *epd;
298 
299 	iface = usb_ifnum_to_if(dev, ifnum);
300 	if (!iface || iface->num_altsetting < altsetting + 1)
301 		return -ENOENT;
302 	*alts = &iface->altsetting[altsetting];
303 	altsd = get_iface_desc(*alts);
304 	if (altsd->bAlternateSetting != altsetting ||
305 	    altsd->bInterfaceClass != USB_CLASS_VENDOR_SPEC ||
306 	    (altsd->bInterfaceSubClass != 2 &&
307 	     altsd->bInterfaceProtocol != 2   ) ||
308 	    altsd->bNumEndpoints < 1)
309 		return -ENOENT;
310 	epd = get_endpoint(*alts, 0);
311 	if (!usb_endpoint_is_isoc_in(epd) ||
312 	    (epd->bmAttributes & USB_ENDPOINT_USAGE_MASK) !=
313 					USB_ENDPOINT_USAGE_IMPLICIT_FB)
314 		return -ENOENT;
315 	*ep = epd->bEndpointAddress;
316 	return 0;
317 }
318 
319 /* Setup an implicit feedback endpoint from a quirk. Returns 0 if no quirk
320  * applies. Returns 1 if a quirk was found.
321  */
322 static int set_sync_ep_implicit_fb_quirk(struct snd_usb_substream *subs,
323 					 struct usb_device *dev,
324 					 struct usb_interface_descriptor *altsd,
325 					 unsigned int attr)
326 {
327 	struct usb_host_interface *alts;
328 	struct usb_interface *iface;
329 	unsigned int ep;
330 	unsigned int ifnum;
331 
332 	/* Implicit feedback sync EPs consumers are always playback EPs */
333 	if (subs->direction != SNDRV_PCM_STREAM_PLAYBACK)
334 		return 0;
335 
336 	switch (subs->stream->chip->usb_id) {
337 	case USB_ID(0x0763, 0x2030): /* M-Audio Fast Track C400 */
338 	case USB_ID(0x0763, 0x2031): /* M-Audio Fast Track C600 */
339 		ep = 0x81;
340 		ifnum = 3;
341 		goto add_sync_ep_from_ifnum;
342 	case USB_ID(0x0763, 0x2080): /* M-Audio FastTrack Ultra */
343 	case USB_ID(0x0763, 0x2081):
344 		ep = 0x81;
345 		ifnum = 2;
346 		goto add_sync_ep_from_ifnum;
347 	case USB_ID(0x2466, 0x8003): /* Fractal Audio Axe-Fx II */
348 		ep = 0x86;
349 		ifnum = 2;
350 		goto add_sync_ep_from_ifnum;
351 	case USB_ID(0x2466, 0x8010): /* Fractal Audio Axe-Fx III */
352 		ep = 0x81;
353 		ifnum = 2;
354 		goto add_sync_ep_from_ifnum;
355 	case USB_ID(0x1397, 0x0001): /* Behringer UFX1604 */
356 	case USB_ID(0x1397, 0x0002): /* Behringer UFX1204 */
357 		ep = 0x81;
358 		ifnum = 1;
359 		goto add_sync_ep_from_ifnum;
360 	case USB_ID(0x07fd, 0x0004): /* MOTU MicroBook II */
361 		ep = 0x84;
362 		ifnum = 0;
363 		goto add_sync_ep_from_ifnum;
364 	case USB_ID(0x0582, 0x01d8): /* BOSS Katana */
365 		/* BOSS Katana amplifiers do not need quirks */
366 		return 0;
367 	}
368 
369 	if (attr == USB_ENDPOINT_SYNC_ASYNC &&
370 	    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
371 	    altsd->bInterfaceProtocol == 2 &&
372 	    altsd->bNumEndpoints == 1 &&
373 	    USB_ID_VENDOR(subs->stream->chip->usb_id) == 0x0582 /* Roland */ &&
374 	    search_roland_implicit_fb(dev, altsd->bInterfaceNumber + 1,
375 				      altsd->bAlternateSetting,
376 				      &alts, &ep) >= 0) {
377 		goto add_sync_ep;
378 	}
379 
380 	/* No quirk */
381 	return 0;
382 
383 add_sync_ep_from_ifnum:
384 	iface = usb_ifnum_to_if(dev, ifnum);
385 
386 	if (!iface || iface->num_altsetting == 0)
387 		return -EINVAL;
388 
389 	alts = &iface->altsetting[1];
390 
391 add_sync_ep:
392 	subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
393 						   alts, ep, !subs->direction,
394 						   SND_USB_ENDPOINT_TYPE_DATA);
395 	if (!subs->sync_endpoint)
396 		return -EINVAL;
397 
398 	subs->data_endpoint->sync_master = subs->sync_endpoint;
399 
400 	return 1;
401 }
402 
403 static int set_sync_endpoint(struct snd_usb_substream *subs,
404 			     struct audioformat *fmt,
405 			     struct usb_device *dev,
406 			     struct usb_host_interface *alts,
407 			     struct usb_interface_descriptor *altsd)
408 {
409 	int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
410 	unsigned int ep, attr;
411 	bool implicit_fb;
412 	int err;
413 
414 	/* we need a sync pipe in async OUT or adaptive IN mode */
415 	/* check the number of EP, since some devices have broken
416 	 * descriptors which fool us.  if it has only one EP,
417 	 * assume it as adaptive-out or sync-in.
418 	 */
419 	attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
420 
421 	if ((is_playback && (attr != USB_ENDPOINT_SYNC_ASYNC)) ||
422 		(!is_playback && (attr != USB_ENDPOINT_SYNC_ADAPTIVE))) {
423 
424 		/*
425 		 * In these modes the notion of sync_endpoint is irrelevant.
426 		 * Reset pointers to avoid using stale data from previously
427 		 * used settings, e.g. when configuration and endpoints were
428 		 * changed
429 		 */
430 
431 		subs->sync_endpoint = NULL;
432 		subs->data_endpoint->sync_master = NULL;
433 	}
434 
435 	err = set_sync_ep_implicit_fb_quirk(subs, dev, altsd, attr);
436 	if (err < 0)
437 		return err;
438 
439 	/* endpoint set by quirk */
440 	if (err > 0)
441 		return 0;
442 
443 	if (altsd->bNumEndpoints < 2)
444 		return 0;
445 
446 	if ((is_playback && (attr == USB_ENDPOINT_SYNC_SYNC ||
447 			     attr == USB_ENDPOINT_SYNC_ADAPTIVE)) ||
448 	    (!is_playback && attr != USB_ENDPOINT_SYNC_ADAPTIVE))
449 		return 0;
450 
451 	/*
452 	 * In case of illegal SYNC_NONE for OUT endpoint, we keep going to see
453 	 * if we don't find a sync endpoint, as on M-Audio Transit. In case of
454 	 * error fall back to SYNC mode and don't create sync endpoint
455 	 */
456 
457 	/* check sync-pipe endpoint */
458 	/* ... and check descriptor size before accessing bSynchAddress
459 	   because there is a version of the SB Audigy 2 NX firmware lacking
460 	   the audio fields in the endpoint descriptors */
461 	if ((get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) != USB_ENDPOINT_XFER_ISOC ||
462 	    (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
463 	     get_endpoint(alts, 1)->bSynchAddress != 0)) {
464 		dev_err(&dev->dev,
465 			"%d:%d : invalid sync pipe. bmAttributes %02x, bLength %d, bSynchAddress %02x\n",
466 			   fmt->iface, fmt->altsetting,
467 			   get_endpoint(alts, 1)->bmAttributes,
468 			   get_endpoint(alts, 1)->bLength,
469 			   get_endpoint(alts, 1)->bSynchAddress);
470 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
471 			return 0;
472 		return -EINVAL;
473 	}
474 	ep = get_endpoint(alts, 1)->bEndpointAddress;
475 	if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
476 	    get_endpoint(alts, 0)->bSynchAddress != 0 &&
477 	    ((is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
478 	     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
479 		dev_err(&dev->dev,
480 			"%d:%d : invalid sync pipe. is_playback %d, ep %02x, bSynchAddress %02x\n",
481 			   fmt->iface, fmt->altsetting,
482 			   is_playback, ep, get_endpoint(alts, 0)->bSynchAddress);
483 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
484 			return 0;
485 		return -EINVAL;
486 	}
487 
488 	implicit_fb = (get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_USAGE_MASK)
489 			== USB_ENDPOINT_USAGE_IMPLICIT_FB;
490 
491 	subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
492 						   alts, ep, !subs->direction,
493 						   implicit_fb ?
494 							SND_USB_ENDPOINT_TYPE_DATA :
495 							SND_USB_ENDPOINT_TYPE_SYNC);
496 	if (!subs->sync_endpoint) {
497 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
498 			return 0;
499 		return -EINVAL;
500 	}
501 
502 	subs->data_endpoint->sync_master = subs->sync_endpoint;
503 
504 	return 0;
505 }
506 
507 /*
508  * find a matching format and set up the interface
509  */
510 static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
511 {
512 	struct usb_device *dev = subs->dev;
513 	struct usb_host_interface *alts;
514 	struct usb_interface_descriptor *altsd;
515 	struct usb_interface *iface;
516 	int err;
517 
518 	iface = usb_ifnum_to_if(dev, fmt->iface);
519 	if (WARN_ON(!iface))
520 		return -EINVAL;
521 	alts = usb_altnum_to_altsetting(iface, fmt->altsetting);
522 	altsd = get_iface_desc(alts);
523 	if (WARN_ON(altsd->bAlternateSetting != fmt->altsetting))
524 		return -EINVAL;
525 
526 	if (fmt == subs->cur_audiofmt && !subs->need_setup_fmt)
527 		return 0;
528 
529 	/* close the old interface */
530 	if (subs->interface >= 0 && (subs->interface != fmt->iface || subs->need_setup_fmt)) {
531 		if (!subs->stream->chip->keep_iface) {
532 			err = usb_set_interface(subs->dev, subs->interface, 0);
533 			if (err < 0) {
534 				dev_err(&dev->dev,
535 					"%d:%d: return to setting 0 failed (%d)\n",
536 					fmt->iface, fmt->altsetting, err);
537 				return -EIO;
538 			}
539 		}
540 		subs->interface = -1;
541 		subs->altset_idx = 0;
542 	}
543 
544 	if (subs->need_setup_fmt)
545 		subs->need_setup_fmt = false;
546 
547 	/* set interface */
548 	if (iface->cur_altsetting != alts) {
549 		err = snd_usb_select_mode_quirk(subs, fmt);
550 		if (err < 0)
551 			return -EIO;
552 
553 		err = usb_set_interface(dev, fmt->iface, fmt->altsetting);
554 		if (err < 0) {
555 			dev_err(&dev->dev,
556 				"%d:%d: usb_set_interface failed (%d)\n",
557 				fmt->iface, fmt->altsetting, err);
558 			return -EIO;
559 		}
560 		dev_dbg(&dev->dev, "setting usb interface %d:%d\n",
561 			fmt->iface, fmt->altsetting);
562 		snd_usb_set_interface_quirk(dev);
563 	}
564 
565 	subs->interface = fmt->iface;
566 	subs->altset_idx = fmt->altset_idx;
567 	subs->data_endpoint = snd_usb_add_endpoint(subs->stream->chip,
568 						   alts, fmt->endpoint, subs->direction,
569 						   SND_USB_ENDPOINT_TYPE_DATA);
570 
571 	if (!subs->data_endpoint)
572 		return -EINVAL;
573 
574 	err = set_sync_endpoint(subs, fmt, dev, alts, altsd);
575 	if (err < 0)
576 		return err;
577 
578 	err = snd_usb_init_pitch(subs->stream->chip, fmt->iface, alts, fmt);
579 	if (err < 0)
580 		return err;
581 
582 	subs->cur_audiofmt = fmt;
583 
584 	snd_usb_set_format_quirk(subs, fmt);
585 
586 	return 0;
587 }
588 
589 /*
590  * Return the score of matching two audioformats.
591  * Veto the audioformat if:
592  * - It has no channels for some reason.
593  * - Requested PCM format is not supported.
594  * - Requested sample rate is not supported.
595  */
596 static int match_endpoint_audioformats(struct snd_usb_substream *subs,
597 				       struct audioformat *fp,
598 				       struct audioformat *match, int rate,
599 				       snd_pcm_format_t pcm_format)
600 {
601 	int i;
602 	int score = 0;
603 
604 	if (fp->channels < 1) {
605 		dev_dbg(&subs->dev->dev,
606 			"%s: (fmt @%p) no channels\n", __func__, fp);
607 		return 0;
608 	}
609 
610 	if (!(fp->formats & pcm_format_to_bits(pcm_format))) {
611 		dev_dbg(&subs->dev->dev,
612 			"%s: (fmt @%p) no match for format %d\n", __func__,
613 			fp, pcm_format);
614 		return 0;
615 	}
616 
617 	for (i = 0; i < fp->nr_rates; i++) {
618 		if (fp->rate_table[i] == rate) {
619 			score++;
620 			break;
621 		}
622 	}
623 	if (!score) {
624 		dev_dbg(&subs->dev->dev,
625 			"%s: (fmt @%p) no match for rate %d\n", __func__,
626 			fp, rate);
627 		return 0;
628 	}
629 
630 	if (fp->channels == match->channels)
631 		score++;
632 
633 	dev_dbg(&subs->dev->dev,
634 		"%s: (fmt @%p) score %d\n", __func__, fp, score);
635 
636 	return score;
637 }
638 
639 /*
640  * Configure the sync ep using the rate and pcm format of the data ep.
641  */
642 static int configure_sync_endpoint(struct snd_usb_substream *subs)
643 {
644 	int ret;
645 	struct audioformat *fp;
646 	struct audioformat *sync_fp = NULL;
647 	int cur_score = 0;
648 	int sync_period_bytes = subs->period_bytes;
649 	struct snd_usb_substream *sync_subs =
650 		&subs->stream->substream[subs->direction ^ 1];
651 
652 	if (subs->sync_endpoint->type != SND_USB_ENDPOINT_TYPE_DATA ||
653 	    !subs->stream)
654 		return snd_usb_endpoint_set_params(subs->sync_endpoint,
655 						   subs->pcm_format,
656 						   subs->channels,
657 						   subs->period_bytes,
658 						   0, 0,
659 						   subs->cur_rate,
660 						   subs->cur_audiofmt,
661 						   NULL);
662 
663 	/* Try to find the best matching audioformat. */
664 	list_for_each_entry(fp, &sync_subs->fmt_list, list) {
665 		int score = match_endpoint_audioformats(subs,
666 							fp, subs->cur_audiofmt,
667 			subs->cur_rate, subs->pcm_format);
668 
669 		if (score > cur_score) {
670 			sync_fp = fp;
671 			cur_score = score;
672 		}
673 	}
674 
675 	if (unlikely(sync_fp == NULL)) {
676 		dev_err(&subs->dev->dev,
677 			"%s: no valid audioformat for sync ep %x found\n",
678 			__func__, sync_subs->ep_num);
679 		return -EINVAL;
680 	}
681 
682 	/*
683 	 * Recalculate the period bytes if channel number differ between
684 	 * data and sync ep audioformat.
685 	 */
686 	if (sync_fp->channels != subs->channels) {
687 		sync_period_bytes = (subs->period_bytes / subs->channels) *
688 			sync_fp->channels;
689 		dev_dbg(&subs->dev->dev,
690 			"%s: adjusted sync ep period bytes (%d -> %d)\n",
691 			__func__, subs->period_bytes, sync_period_bytes);
692 	}
693 
694 	ret = snd_usb_endpoint_set_params(subs->sync_endpoint,
695 					  subs->pcm_format,
696 					  sync_fp->channels,
697 					  sync_period_bytes,
698 					  0, 0,
699 					  subs->cur_rate,
700 					  sync_fp,
701 					  NULL);
702 
703 	return ret;
704 }
705 
706 /*
707  * configure endpoint params
708  *
709  * called  during initial setup and upon resume
710  */
711 static int configure_endpoint(struct snd_usb_substream *subs)
712 {
713 	int ret;
714 
715 	/* format changed */
716 	stop_endpoints(subs);
717 	sync_pending_stops(subs);
718 	ret = snd_usb_endpoint_set_params(subs->data_endpoint,
719 					  subs->pcm_format,
720 					  subs->channels,
721 					  subs->period_bytes,
722 					  subs->period_frames,
723 					  subs->buffer_periods,
724 					  subs->cur_rate,
725 					  subs->cur_audiofmt,
726 					  subs->sync_endpoint);
727 	if (ret < 0)
728 		return ret;
729 
730 	if (subs->sync_endpoint)
731 		ret = configure_sync_endpoint(subs);
732 
733 	return ret;
734 }
735 
736 static int snd_usb_pcm_change_state(struct snd_usb_substream *subs, int state)
737 {
738 	int ret;
739 
740 	if (!subs->str_pd)
741 		return 0;
742 
743 	ret = snd_usb_power_domain_set(subs->stream->chip, subs->str_pd, state);
744 	if (ret < 0) {
745 		dev_err(&subs->dev->dev,
746 			"Cannot change Power Domain ID: %d to state: %d. Err: %d\n",
747 			subs->str_pd->pd_id, state, ret);
748 		return ret;
749 	}
750 
751 	return 0;
752 }
753 
754 int snd_usb_pcm_suspend(struct snd_usb_stream *as)
755 {
756 	int ret;
757 
758 	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D2);
759 	if (ret < 0)
760 		return ret;
761 
762 	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D2);
763 	if (ret < 0)
764 		return ret;
765 
766 	return 0;
767 }
768 
769 int snd_usb_pcm_resume(struct snd_usb_stream *as)
770 {
771 	int ret;
772 
773 	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D1);
774 	if (ret < 0)
775 		return ret;
776 
777 	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D1);
778 	if (ret < 0)
779 		return ret;
780 
781 	return 0;
782 }
783 
784 /*
785  * hw_params callback
786  *
787  * allocate a buffer and set the given audio format.
788  *
789  * so far we use a physically linear buffer although packetize transfer
790  * doesn't need a continuous area.
791  * if sg buffer is supported on the later version of alsa, we'll follow
792  * that.
793  */
794 static int snd_usb_hw_params(struct snd_pcm_substream *substream,
795 			     struct snd_pcm_hw_params *hw_params)
796 {
797 	struct snd_usb_substream *subs = substream->runtime->private_data;
798 	struct audioformat *fmt;
799 	int ret;
800 
801 	ret = snd_media_start_pipeline(subs);
802 	if (ret)
803 		return ret;
804 
805 	subs->pcm_format = params_format(hw_params);
806 	subs->period_bytes = params_period_bytes(hw_params);
807 	subs->period_frames = params_period_size(hw_params);
808 	subs->buffer_periods = params_periods(hw_params);
809 	subs->channels = params_channels(hw_params);
810 	subs->cur_rate = params_rate(hw_params);
811 
812 	fmt = find_format(subs);
813 	if (!fmt) {
814 		dev_dbg(&subs->dev->dev,
815 			"cannot set format: format = %#x, rate = %d, channels = %d\n",
816 			   subs->pcm_format, subs->cur_rate, subs->channels);
817 		ret = -EINVAL;
818 		goto stop_pipeline;
819 	}
820 
821 	ret = snd_usb_lock_shutdown(subs->stream->chip);
822 	if (ret < 0)
823 		goto stop_pipeline;
824 
825 	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
826 	if (ret < 0)
827 		goto unlock;
828 
829 	ret = set_format(subs, fmt);
830 	if (ret < 0)
831 		goto unlock;
832 
833 	subs->interface = fmt->iface;
834 	subs->altset_idx = fmt->altset_idx;
835 	subs->need_setup_ep = true;
836 
837  unlock:
838 	snd_usb_unlock_shutdown(subs->stream->chip);
839 	if (ret < 0)
840 		goto stop_pipeline;
841 	return ret;
842 
843  stop_pipeline:
844 	snd_media_stop_pipeline(subs);
845 	return ret;
846 }
847 
848 /*
849  * hw_free callback
850  *
851  * reset the audio format and release the buffer
852  */
853 static int snd_usb_hw_free(struct snd_pcm_substream *substream)
854 {
855 	struct snd_usb_substream *subs = substream->runtime->private_data;
856 
857 	snd_media_stop_pipeline(subs);
858 	subs->cur_audiofmt = NULL;
859 	subs->cur_rate = 0;
860 	subs->period_bytes = 0;
861 	if (!snd_usb_lock_shutdown(subs->stream->chip)) {
862 		stop_endpoints(subs);
863 		sync_pending_stops(subs);
864 		snd_usb_endpoint_deactivate(subs->sync_endpoint);
865 		snd_usb_endpoint_deactivate(subs->data_endpoint);
866 		snd_usb_unlock_shutdown(subs->stream->chip);
867 	}
868 
869 	return 0;
870 }
871 
872 /*
873  * prepare callback
874  *
875  * only a few subtle things...
876  */
877 static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
878 {
879 	struct snd_pcm_runtime *runtime = substream->runtime;
880 	struct snd_usb_substream *subs = runtime->private_data;
881 	struct usb_host_interface *alts;
882 	struct usb_interface *iface;
883 	int ret;
884 
885 	if (! subs->cur_audiofmt) {
886 		dev_err(&subs->dev->dev, "no format is specified!\n");
887 		return -ENXIO;
888 	}
889 
890 	ret = snd_usb_lock_shutdown(subs->stream->chip);
891 	if (ret < 0)
892 		return ret;
893 	if (snd_BUG_ON(!subs->data_endpoint)) {
894 		ret = -EIO;
895 		goto unlock;
896 	}
897 
898 	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
899 	if (ret < 0)
900 		goto unlock;
901 
902 	ret = set_format(subs, subs->cur_audiofmt);
903 	if (ret < 0)
904 		goto unlock;
905 
906 	if (subs->need_setup_ep) {
907 
908 		iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
909 		alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
910 		ret = snd_usb_init_sample_rate(subs->stream->chip,
911 					       subs->cur_audiofmt->iface,
912 					       alts,
913 					       subs->cur_audiofmt,
914 					       subs->cur_rate);
915 		if (ret < 0)
916 			goto unlock;
917 
918 		ret = configure_endpoint(subs);
919 		if (ret < 0)
920 			goto unlock;
921 		subs->need_setup_ep = false;
922 	}
923 
924 	/* some unit conversions in runtime */
925 	subs->data_endpoint->maxframesize =
926 		bytes_to_frames(runtime, subs->data_endpoint->maxpacksize);
927 	subs->data_endpoint->curframesize =
928 		bytes_to_frames(runtime, subs->data_endpoint->curpacksize);
929 
930 	/* reset the pointer */
931 	subs->hwptr_done = 0;
932 	subs->transfer_done = 0;
933 	subs->last_delay = 0;
934 	subs->last_frame_number = 0;
935 	runtime->delay = 0;
936 
937 	/* for playback, submit the URBs now; otherwise, the first hwptr_done
938 	 * updates for all URBs would happen at the same time when starting */
939 	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK)
940 		ret = start_endpoints(subs);
941 
942  unlock:
943 	snd_usb_unlock_shutdown(subs->stream->chip);
944 	return ret;
945 }
946 
947 static const struct snd_pcm_hardware snd_usb_hardware =
948 {
949 	.info =			SNDRV_PCM_INFO_MMAP |
950 				SNDRV_PCM_INFO_MMAP_VALID |
951 				SNDRV_PCM_INFO_BATCH |
952 				SNDRV_PCM_INFO_INTERLEAVED |
953 				SNDRV_PCM_INFO_BLOCK_TRANSFER |
954 				SNDRV_PCM_INFO_PAUSE,
955 	.buffer_bytes_max =	1024 * 1024,
956 	.period_bytes_min =	64,
957 	.period_bytes_max =	512 * 1024,
958 	.periods_min =		2,
959 	.periods_max =		1024,
960 };
961 
962 static int hw_check_valid_format(struct snd_usb_substream *subs,
963 				 struct snd_pcm_hw_params *params,
964 				 struct audioformat *fp)
965 {
966 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
967 	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
968 	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
969 	struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
970 	struct snd_mask check_fmts;
971 	unsigned int ptime;
972 
973 	/* check the format */
974 	snd_mask_none(&check_fmts);
975 	check_fmts.bits[0] = (u32)fp->formats;
976 	check_fmts.bits[1] = (u32)(fp->formats >> 32);
977 	snd_mask_intersect(&check_fmts, fmts);
978 	if (snd_mask_empty(&check_fmts)) {
979 		hwc_debug("   > check: no supported format %d\n", fp->format);
980 		return 0;
981 	}
982 	/* check the channels */
983 	if (fp->channels < ct->min || fp->channels > ct->max) {
984 		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
985 		return 0;
986 	}
987 	/* check the rate is within the range */
988 	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
989 		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
990 		return 0;
991 	}
992 	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
993 		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
994 		return 0;
995 	}
996 	/* check whether the period time is >= the data packet interval */
997 	if (subs->speed != USB_SPEED_FULL) {
998 		ptime = 125 * (1 << fp->datainterval);
999 		if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
1000 			hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
1001 			return 0;
1002 		}
1003 	}
1004 	return 1;
1005 }
1006 
1007 static int hw_rule_rate(struct snd_pcm_hw_params *params,
1008 			struct snd_pcm_hw_rule *rule)
1009 {
1010 	struct snd_usb_substream *subs = rule->private;
1011 	struct audioformat *fp;
1012 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
1013 	unsigned int rmin, rmax;
1014 	int changed;
1015 
1016 	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
1017 	changed = 0;
1018 	rmin = rmax = 0;
1019 	list_for_each_entry(fp, &subs->fmt_list, list) {
1020 		if (!hw_check_valid_format(subs, params, fp))
1021 			continue;
1022 		if (changed++) {
1023 			if (rmin > fp->rate_min)
1024 				rmin = fp->rate_min;
1025 			if (rmax < fp->rate_max)
1026 				rmax = fp->rate_max;
1027 		} else {
1028 			rmin = fp->rate_min;
1029 			rmax = fp->rate_max;
1030 		}
1031 	}
1032 
1033 	if (!changed) {
1034 		hwc_debug("  --> get empty\n");
1035 		it->empty = 1;
1036 		return -EINVAL;
1037 	}
1038 
1039 	changed = 0;
1040 	if (it->min < rmin) {
1041 		it->min = rmin;
1042 		it->openmin = 0;
1043 		changed = 1;
1044 	}
1045 	if (it->max > rmax) {
1046 		it->max = rmax;
1047 		it->openmax = 0;
1048 		changed = 1;
1049 	}
1050 	if (snd_interval_checkempty(it)) {
1051 		it->empty = 1;
1052 		return -EINVAL;
1053 	}
1054 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
1055 	return changed;
1056 }
1057 
1058 
1059 static int hw_rule_channels(struct snd_pcm_hw_params *params,
1060 			    struct snd_pcm_hw_rule *rule)
1061 {
1062 	struct snd_usb_substream *subs = rule->private;
1063 	struct audioformat *fp;
1064 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
1065 	unsigned int rmin, rmax;
1066 	int changed;
1067 
1068 	hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
1069 	changed = 0;
1070 	rmin = rmax = 0;
1071 	list_for_each_entry(fp, &subs->fmt_list, list) {
1072 		if (!hw_check_valid_format(subs, params, fp))
1073 			continue;
1074 		if (changed++) {
1075 			if (rmin > fp->channels)
1076 				rmin = fp->channels;
1077 			if (rmax < fp->channels)
1078 				rmax = fp->channels;
1079 		} else {
1080 			rmin = fp->channels;
1081 			rmax = fp->channels;
1082 		}
1083 	}
1084 
1085 	if (!changed) {
1086 		hwc_debug("  --> get empty\n");
1087 		it->empty = 1;
1088 		return -EINVAL;
1089 	}
1090 
1091 	changed = 0;
1092 	if (it->min < rmin) {
1093 		it->min = rmin;
1094 		it->openmin = 0;
1095 		changed = 1;
1096 	}
1097 	if (it->max > rmax) {
1098 		it->max = rmax;
1099 		it->openmax = 0;
1100 		changed = 1;
1101 	}
1102 	if (snd_interval_checkempty(it)) {
1103 		it->empty = 1;
1104 		return -EINVAL;
1105 	}
1106 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
1107 	return changed;
1108 }
1109 
1110 static int hw_rule_format(struct snd_pcm_hw_params *params,
1111 			  struct snd_pcm_hw_rule *rule)
1112 {
1113 	struct snd_usb_substream *subs = rule->private;
1114 	struct audioformat *fp;
1115 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
1116 	u64 fbits;
1117 	u32 oldbits[2];
1118 	int changed;
1119 
1120 	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
1121 	fbits = 0;
1122 	list_for_each_entry(fp, &subs->fmt_list, list) {
1123 		if (!hw_check_valid_format(subs, params, fp))
1124 			continue;
1125 		fbits |= fp->formats;
1126 	}
1127 
1128 	oldbits[0] = fmt->bits[0];
1129 	oldbits[1] = fmt->bits[1];
1130 	fmt->bits[0] &= (u32)fbits;
1131 	fmt->bits[1] &= (u32)(fbits >> 32);
1132 	if (!fmt->bits[0] && !fmt->bits[1]) {
1133 		hwc_debug("  --> get empty\n");
1134 		return -EINVAL;
1135 	}
1136 	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
1137 	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
1138 	return changed;
1139 }
1140 
1141 static int hw_rule_period_time(struct snd_pcm_hw_params *params,
1142 			       struct snd_pcm_hw_rule *rule)
1143 {
1144 	struct snd_usb_substream *subs = rule->private;
1145 	struct audioformat *fp;
1146 	struct snd_interval *it;
1147 	unsigned char min_datainterval;
1148 	unsigned int pmin;
1149 	int changed;
1150 
1151 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
1152 	hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
1153 	min_datainterval = 0xff;
1154 	list_for_each_entry(fp, &subs->fmt_list, list) {
1155 		if (!hw_check_valid_format(subs, params, fp))
1156 			continue;
1157 		min_datainterval = min(min_datainterval, fp->datainterval);
1158 	}
1159 	if (min_datainterval == 0xff) {
1160 		hwc_debug("  --> get empty\n");
1161 		it->empty = 1;
1162 		return -EINVAL;
1163 	}
1164 	pmin = 125 * (1 << min_datainterval);
1165 	changed = 0;
1166 	if (it->min < pmin) {
1167 		it->min = pmin;
1168 		it->openmin = 0;
1169 		changed = 1;
1170 	}
1171 	if (snd_interval_checkempty(it)) {
1172 		it->empty = 1;
1173 		return -EINVAL;
1174 	}
1175 	hwc_debug("  --> (%u,%u) (changed = %d)\n", it->min, it->max, changed);
1176 	return changed;
1177 }
1178 
1179 /*
1180  *  If the device supports unusual bit rates, does the request meet these?
1181  */
1182 static int snd_usb_pcm_check_knot(struct snd_pcm_runtime *runtime,
1183 				  struct snd_usb_substream *subs)
1184 {
1185 	struct audioformat *fp;
1186 	int *rate_list;
1187 	int count = 0, needs_knot = 0;
1188 	int err;
1189 
1190 	kfree(subs->rate_list.list);
1191 	subs->rate_list.list = NULL;
1192 
1193 	list_for_each_entry(fp, &subs->fmt_list, list) {
1194 		if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)
1195 			return 0;
1196 		count += fp->nr_rates;
1197 		if (fp->rates & SNDRV_PCM_RATE_KNOT)
1198 			needs_knot = 1;
1199 	}
1200 	if (!needs_knot)
1201 		return 0;
1202 
1203 	subs->rate_list.list = rate_list =
1204 		kmalloc_array(count, sizeof(int), GFP_KERNEL);
1205 	if (!subs->rate_list.list)
1206 		return -ENOMEM;
1207 	subs->rate_list.count = count;
1208 	subs->rate_list.mask = 0;
1209 	count = 0;
1210 	list_for_each_entry(fp, &subs->fmt_list, list) {
1211 		int i;
1212 		for (i = 0; i < fp->nr_rates; i++)
1213 			rate_list[count++] = fp->rate_table[i];
1214 	}
1215 	err = snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1216 					 &subs->rate_list);
1217 	if (err < 0)
1218 		return err;
1219 
1220 	return 0;
1221 }
1222 
1223 
1224 /*
1225  * set up the runtime hardware information.
1226  */
1227 
1228 static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
1229 {
1230 	struct audioformat *fp;
1231 	unsigned int pt, ptmin;
1232 	int param_period_time_if_needed;
1233 	int err;
1234 
1235 	runtime->hw.formats = subs->formats;
1236 
1237 	runtime->hw.rate_min = 0x7fffffff;
1238 	runtime->hw.rate_max = 0;
1239 	runtime->hw.channels_min = 256;
1240 	runtime->hw.channels_max = 0;
1241 	runtime->hw.rates = 0;
1242 	ptmin = UINT_MAX;
1243 	/* check min/max rates and channels */
1244 	list_for_each_entry(fp, &subs->fmt_list, list) {
1245 		runtime->hw.rates |= fp->rates;
1246 		if (runtime->hw.rate_min > fp->rate_min)
1247 			runtime->hw.rate_min = fp->rate_min;
1248 		if (runtime->hw.rate_max < fp->rate_max)
1249 			runtime->hw.rate_max = fp->rate_max;
1250 		if (runtime->hw.channels_min > fp->channels)
1251 			runtime->hw.channels_min = fp->channels;
1252 		if (runtime->hw.channels_max < fp->channels)
1253 			runtime->hw.channels_max = fp->channels;
1254 		if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
1255 			/* FIXME: there might be more than one audio formats... */
1256 			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
1257 				fp->frame_size;
1258 		}
1259 		pt = 125 * (1 << fp->datainterval);
1260 		ptmin = min(ptmin, pt);
1261 	}
1262 
1263 	param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
1264 	if (subs->speed == USB_SPEED_FULL)
1265 		/* full speed devices have fixed data packet interval */
1266 		ptmin = 1000;
1267 	if (ptmin == 1000)
1268 		/* if period time doesn't go below 1 ms, no rules needed */
1269 		param_period_time_if_needed = -1;
1270 
1271 	err = snd_pcm_hw_constraint_minmax(runtime,
1272 					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1273 					   ptmin, UINT_MAX);
1274 	if (err < 0)
1275 		return err;
1276 
1277 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1278 				  hw_rule_rate, subs,
1279 				  SNDRV_PCM_HW_PARAM_FORMAT,
1280 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1281 				  param_period_time_if_needed,
1282 				  -1);
1283 	if (err < 0)
1284 		return err;
1285 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
1286 				  hw_rule_channels, subs,
1287 				  SNDRV_PCM_HW_PARAM_FORMAT,
1288 				  SNDRV_PCM_HW_PARAM_RATE,
1289 				  param_period_time_if_needed,
1290 				  -1);
1291 	if (err < 0)
1292 		return err;
1293 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1294 				  hw_rule_format, subs,
1295 				  SNDRV_PCM_HW_PARAM_RATE,
1296 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1297 				  param_period_time_if_needed,
1298 				  -1);
1299 	if (err < 0)
1300 		return err;
1301 	if (param_period_time_if_needed >= 0) {
1302 		err = snd_pcm_hw_rule_add(runtime, 0,
1303 					  SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1304 					  hw_rule_period_time, subs,
1305 					  SNDRV_PCM_HW_PARAM_FORMAT,
1306 					  SNDRV_PCM_HW_PARAM_CHANNELS,
1307 					  SNDRV_PCM_HW_PARAM_RATE,
1308 					  -1);
1309 		if (err < 0)
1310 			return err;
1311 	}
1312 	err = snd_usb_pcm_check_knot(runtime, subs);
1313 	if (err < 0)
1314 		return err;
1315 
1316 	return snd_usb_autoresume(subs->stream->chip);
1317 }
1318 
1319 static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
1320 {
1321 	int direction = substream->stream;
1322 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1323 	struct snd_pcm_runtime *runtime = substream->runtime;
1324 	struct snd_usb_substream *subs = &as->substream[direction];
1325 	int ret;
1326 
1327 	subs->interface = -1;
1328 	subs->altset_idx = 0;
1329 	runtime->hw = snd_usb_hardware;
1330 	runtime->private_data = subs;
1331 	subs->pcm_substream = substream;
1332 	/* runtime PM is also done there */
1333 
1334 	/* initialize DSD/DOP context */
1335 	subs->dsd_dop.byte_idx = 0;
1336 	subs->dsd_dop.channel = 0;
1337 	subs->dsd_dop.marker = 1;
1338 
1339 	ret = setup_hw_info(runtime, subs);
1340 	if (ret == 0) {
1341 		ret = snd_media_stream_init(subs, as->pcm, direction);
1342 		if (ret)
1343 			snd_usb_autosuspend(subs->stream->chip);
1344 	}
1345 	return ret;
1346 }
1347 
1348 static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
1349 {
1350 	int direction = substream->stream;
1351 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1352 	struct snd_usb_substream *subs = &as->substream[direction];
1353 	int ret;
1354 
1355 	snd_media_stop_pipeline(subs);
1356 
1357 	if (!as->chip->keep_iface &&
1358 	    subs->interface >= 0 &&
1359 	    !snd_usb_lock_shutdown(subs->stream->chip)) {
1360 		usb_set_interface(subs->dev, subs->interface, 0);
1361 		subs->interface = -1;
1362 		ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
1363 		snd_usb_unlock_shutdown(subs->stream->chip);
1364 		if (ret < 0)
1365 			return ret;
1366 	}
1367 
1368 	subs->pcm_substream = NULL;
1369 	snd_usb_autosuspend(subs->stream->chip);
1370 
1371 	return 0;
1372 }
1373 
1374 /* Since a URB can handle only a single linear buffer, we must use double
1375  * buffering when the data to be transferred overflows the buffer boundary.
1376  * To avoid inconsistencies when updating hwptr_done, we use double buffering
1377  * for all URBs.
1378  */
1379 static void retire_capture_urb(struct snd_usb_substream *subs,
1380 			       struct urb *urb)
1381 {
1382 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1383 	unsigned int stride, frames, bytes, oldptr;
1384 	int i, period_elapsed = 0;
1385 	unsigned long flags;
1386 	unsigned char *cp;
1387 	int current_frame_number;
1388 
1389 	/* read frame number here, update pointer in critical section */
1390 	current_frame_number = usb_get_current_frame_number(subs->dev);
1391 
1392 	stride = runtime->frame_bits >> 3;
1393 
1394 	for (i = 0; i < urb->number_of_packets; i++) {
1395 		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;
1396 		if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
1397 			dev_dbg(&subs->dev->dev, "frame %d active: %d\n",
1398 				i, urb->iso_frame_desc[i].status);
1399 			// continue;
1400 		}
1401 		bytes = urb->iso_frame_desc[i].actual_length;
1402 		frames = bytes / stride;
1403 		if (!subs->txfr_quirk)
1404 			bytes = frames * stride;
1405 		if (bytes % (runtime->sample_bits >> 3) != 0) {
1406 			int oldbytes = bytes;
1407 			bytes = frames * stride;
1408 			dev_warn_ratelimited(&subs->dev->dev,
1409 				 "Corrected urb data len. %d->%d\n",
1410 							oldbytes, bytes);
1411 		}
1412 		/* update the current pointer */
1413 		spin_lock_irqsave(&subs->lock, flags);
1414 		oldptr = subs->hwptr_done;
1415 		subs->hwptr_done += bytes;
1416 		if (subs->hwptr_done >= runtime->buffer_size * stride)
1417 			subs->hwptr_done -= runtime->buffer_size * stride;
1418 		frames = (bytes + (oldptr % stride)) / stride;
1419 		subs->transfer_done += frames;
1420 		if (subs->transfer_done >= runtime->period_size) {
1421 			subs->transfer_done -= runtime->period_size;
1422 			period_elapsed = 1;
1423 		}
1424 		/* capture delay is by construction limited to one URB,
1425 		 * reset delays here
1426 		 */
1427 		runtime->delay = subs->last_delay = 0;
1428 
1429 		/* realign last_frame_number */
1430 		subs->last_frame_number = current_frame_number;
1431 		subs->last_frame_number &= 0xFF; /* keep 8 LSBs */
1432 
1433 		spin_unlock_irqrestore(&subs->lock, flags);
1434 		/* copy a data chunk */
1435 		if (oldptr + bytes > runtime->buffer_size * stride) {
1436 			unsigned int bytes1 =
1437 					runtime->buffer_size * stride - oldptr;
1438 			memcpy(runtime->dma_area + oldptr, cp, bytes1);
1439 			memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
1440 		} else {
1441 			memcpy(runtime->dma_area + oldptr, cp, bytes);
1442 		}
1443 	}
1444 
1445 	if (period_elapsed)
1446 		snd_pcm_period_elapsed(subs->pcm_substream);
1447 }
1448 
1449 static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
1450 					     struct urb *urb, unsigned int bytes)
1451 {
1452 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1453 	unsigned int stride = runtime->frame_bits >> 3;
1454 	unsigned int dst_idx = 0;
1455 	unsigned int src_idx = subs->hwptr_done;
1456 	unsigned int wrap = runtime->buffer_size * stride;
1457 	u8 *dst = urb->transfer_buffer;
1458 	u8 *src = runtime->dma_area;
1459 	u8 marker[] = { 0x05, 0xfa };
1460 
1461 	/*
1462 	 * The DSP DOP format defines a way to transport DSD samples over
1463 	 * normal PCM data endpoints. It requires stuffing of marker bytes
1464 	 * (0x05 and 0xfa, alternating per sample frame), and then expects
1465 	 * 2 additional bytes of actual payload. The whole frame is stored
1466 	 * LSB.
1467 	 *
1468 	 * Hence, for a stereo transport, the buffer layout looks like this,
1469 	 * where L refers to left channel samples and R to right.
1470 	 *
1471 	 *   L1 L2 0x05   R1 R2 0x05   L3 L4 0xfa  R3 R4 0xfa
1472 	 *   L5 L6 0x05   R5 R6 0x05   L7 L8 0xfa  R7 R8 0xfa
1473 	 *   .....
1474 	 *
1475 	 */
1476 
1477 	while (bytes--) {
1478 		if (++subs->dsd_dop.byte_idx == 3) {
1479 			/* frame boundary? */
1480 			dst[dst_idx++] = marker[subs->dsd_dop.marker];
1481 			src_idx += 2;
1482 			subs->dsd_dop.byte_idx = 0;
1483 
1484 			if (++subs->dsd_dop.channel % runtime->channels == 0) {
1485 				/* alternate the marker */
1486 				subs->dsd_dop.marker++;
1487 				subs->dsd_dop.marker %= ARRAY_SIZE(marker);
1488 				subs->dsd_dop.channel = 0;
1489 			}
1490 		} else {
1491 			/* stuff the DSD payload */
1492 			int idx = (src_idx + subs->dsd_dop.byte_idx - 1) % wrap;
1493 
1494 			if (subs->cur_audiofmt->dsd_bitrev)
1495 				dst[dst_idx++] = bitrev8(src[idx]);
1496 			else
1497 				dst[dst_idx++] = src[idx];
1498 
1499 			subs->hwptr_done++;
1500 		}
1501 	}
1502 	if (subs->hwptr_done >= runtime->buffer_size * stride)
1503 		subs->hwptr_done -= runtime->buffer_size * stride;
1504 }
1505 
1506 static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
1507 			int offset, int stride, unsigned int bytes)
1508 {
1509 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1510 
1511 	if (subs->hwptr_done + bytes > runtime->buffer_size * stride) {
1512 		/* err, the transferred area goes over buffer boundary. */
1513 		unsigned int bytes1 =
1514 			runtime->buffer_size * stride - subs->hwptr_done;
1515 		memcpy(urb->transfer_buffer + offset,
1516 		       runtime->dma_area + subs->hwptr_done, bytes1);
1517 		memcpy(urb->transfer_buffer + offset + bytes1,
1518 		       runtime->dma_area, bytes - bytes1);
1519 	} else {
1520 		memcpy(urb->transfer_buffer + offset,
1521 		       runtime->dma_area + subs->hwptr_done, bytes);
1522 	}
1523 	subs->hwptr_done += bytes;
1524 	if (subs->hwptr_done >= runtime->buffer_size * stride)
1525 		subs->hwptr_done -= runtime->buffer_size * stride;
1526 }
1527 
1528 static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
1529 				      struct urb *urb, int stride,
1530 				      unsigned int bytes)
1531 {
1532 	__le32 packet_length;
1533 	int i;
1534 
1535 	/* Put __le32 length descriptor at start of each packet. */
1536 	for (i = 0; i < urb->number_of_packets; i++) {
1537 		unsigned int length = urb->iso_frame_desc[i].length;
1538 		unsigned int offset = urb->iso_frame_desc[i].offset;
1539 
1540 		packet_length = cpu_to_le32(length);
1541 		offset += i * sizeof(packet_length);
1542 		urb->iso_frame_desc[i].offset = offset;
1543 		urb->iso_frame_desc[i].length += sizeof(packet_length);
1544 		memcpy(urb->transfer_buffer + offset,
1545 		       &packet_length, sizeof(packet_length));
1546 		copy_to_urb(subs, urb, offset + sizeof(packet_length),
1547 			    stride, length);
1548 	}
1549 	/* Adjust transfer size accordingly. */
1550 	bytes += urb->number_of_packets * sizeof(packet_length);
1551 	return bytes;
1552 }
1553 
1554 static void prepare_playback_urb(struct snd_usb_substream *subs,
1555 				 struct urb *urb)
1556 {
1557 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1558 	struct snd_usb_endpoint *ep = subs->data_endpoint;
1559 	struct snd_urb_ctx *ctx = urb->context;
1560 	unsigned int counts, frames, bytes;
1561 	int i, stride, period_elapsed = 0;
1562 	unsigned long flags;
1563 
1564 	stride = runtime->frame_bits >> 3;
1565 
1566 	frames = 0;
1567 	urb->number_of_packets = 0;
1568 	spin_lock_irqsave(&subs->lock, flags);
1569 	subs->frame_limit += ep->max_urb_frames;
1570 	for (i = 0; i < ctx->packets; i++) {
1571 		if (ctx->packet_size[i])
1572 			counts = ctx->packet_size[i];
1573 		else
1574 			counts = snd_usb_endpoint_next_packet_size(ep);
1575 
1576 		/* set up descriptor */
1577 		urb->iso_frame_desc[i].offset = frames * ep->stride;
1578 		urb->iso_frame_desc[i].length = counts * ep->stride;
1579 		frames += counts;
1580 		urb->number_of_packets++;
1581 		subs->transfer_done += counts;
1582 		if (subs->transfer_done >= runtime->period_size) {
1583 			subs->transfer_done -= runtime->period_size;
1584 			subs->frame_limit = 0;
1585 			period_elapsed = 1;
1586 			if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
1587 				if (subs->transfer_done > 0) {
1588 					/* FIXME: fill-max mode is not
1589 					 * supported yet */
1590 					frames -= subs->transfer_done;
1591 					counts -= subs->transfer_done;
1592 					urb->iso_frame_desc[i].length =
1593 						counts * ep->stride;
1594 					subs->transfer_done = 0;
1595 				}
1596 				i++;
1597 				if (i < ctx->packets) {
1598 					/* add a transfer delimiter */
1599 					urb->iso_frame_desc[i].offset =
1600 						frames * ep->stride;
1601 					urb->iso_frame_desc[i].length = 0;
1602 					urb->number_of_packets++;
1603 				}
1604 				break;
1605 			}
1606 		}
1607 		/* finish at the period boundary or after enough frames */
1608 		if ((period_elapsed ||
1609 				subs->transfer_done >= subs->frame_limit) &&
1610 		    !snd_usb_endpoint_implicit_feedback_sink(ep))
1611 			break;
1612 	}
1613 	bytes = frames * ep->stride;
1614 
1615 	if (unlikely(subs->pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
1616 		     subs->cur_audiofmt->dsd_dop)) {
1617 		fill_playback_urb_dsd_dop(subs, urb, bytes);
1618 	} else if (unlikely(subs->pcm_format == SNDRV_PCM_FORMAT_DSD_U8 &&
1619 			   subs->cur_audiofmt->dsd_bitrev)) {
1620 		/* bit-reverse the bytes */
1621 		u8 *buf = urb->transfer_buffer;
1622 		for (i = 0; i < bytes; i++) {
1623 			int idx = (subs->hwptr_done + i)
1624 				% (runtime->buffer_size * stride);
1625 			buf[i] = bitrev8(runtime->dma_area[idx]);
1626 		}
1627 
1628 		subs->hwptr_done += bytes;
1629 		if (subs->hwptr_done >= runtime->buffer_size * stride)
1630 			subs->hwptr_done -= runtime->buffer_size * stride;
1631 	} else {
1632 		/* usual PCM */
1633 		if (!subs->tx_length_quirk)
1634 			copy_to_urb(subs, urb, 0, stride, bytes);
1635 		else
1636 			bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
1637 			/* bytes is now amount of outgoing data */
1638 	}
1639 
1640 	/* update delay with exact number of samples queued */
1641 	runtime->delay = subs->last_delay;
1642 	runtime->delay += frames;
1643 	subs->last_delay = runtime->delay;
1644 
1645 	/* realign last_frame_number */
1646 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1647 	subs->last_frame_number &= 0xFF; /* keep 8 LSBs */
1648 
1649 	if (subs->trigger_tstamp_pending_update) {
1650 		/* this is the first actual URB submitted,
1651 		 * update trigger timestamp to reflect actual start time
1652 		 */
1653 		snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
1654 		subs->trigger_tstamp_pending_update = false;
1655 	}
1656 
1657 	spin_unlock_irqrestore(&subs->lock, flags);
1658 	urb->transfer_buffer_length = bytes;
1659 	if (period_elapsed)
1660 		snd_pcm_period_elapsed(subs->pcm_substream);
1661 }
1662 
1663 /*
1664  * process after playback data complete
1665  * - decrease the delay count again
1666  */
1667 static void retire_playback_urb(struct snd_usb_substream *subs,
1668 			       struct urb *urb)
1669 {
1670 	unsigned long flags;
1671 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1672 	struct snd_usb_endpoint *ep = subs->data_endpoint;
1673 	int processed = urb->transfer_buffer_length / ep->stride;
1674 	int est_delay;
1675 
1676 	/* ignore the delay accounting when procssed=0 is given, i.e.
1677 	 * silent payloads are procssed before handling the actual data
1678 	 */
1679 	if (!processed)
1680 		return;
1681 
1682 	spin_lock_irqsave(&subs->lock, flags);
1683 	if (!subs->last_delay)
1684 		goto out; /* short path */
1685 
1686 	est_delay = snd_usb_pcm_delay(subs, runtime->rate);
1687 	/* update delay with exact number of samples played */
1688 	if (processed > subs->last_delay)
1689 		subs->last_delay = 0;
1690 	else
1691 		subs->last_delay -= processed;
1692 	runtime->delay = subs->last_delay;
1693 
1694 	/*
1695 	 * Report when delay estimate is off by more than 2ms.
1696 	 * The error should be lower than 2ms since the estimate relies
1697 	 * on two reads of a counter updated every ms.
1698 	 */
1699 	if (abs(est_delay - subs->last_delay) * 1000 > runtime->rate * 2)
1700 		dev_dbg_ratelimited(&subs->dev->dev,
1701 			"delay: estimated %d, actual %d\n",
1702 			est_delay, subs->last_delay);
1703 
1704 	if (!subs->running) {
1705 		/* update last_frame_number for delay counting here since
1706 		 * prepare_playback_urb won't be called during pause
1707 		 */
1708 		subs->last_frame_number =
1709 			usb_get_current_frame_number(subs->dev) & 0xff;
1710 	}
1711 
1712  out:
1713 	spin_unlock_irqrestore(&subs->lock, flags);
1714 }
1715 
1716 static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
1717 					      int cmd)
1718 {
1719 	struct snd_usb_substream *subs = substream->runtime->private_data;
1720 
1721 	switch (cmd) {
1722 	case SNDRV_PCM_TRIGGER_START:
1723 		subs->trigger_tstamp_pending_update = true;
1724 		/* fall through */
1725 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1726 		subs->data_endpoint->prepare_data_urb = prepare_playback_urb;
1727 		subs->data_endpoint->retire_data_urb = retire_playback_urb;
1728 		subs->running = 1;
1729 		return 0;
1730 	case SNDRV_PCM_TRIGGER_STOP:
1731 		stop_endpoints(subs);
1732 		subs->running = 0;
1733 		return 0;
1734 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1735 		subs->data_endpoint->prepare_data_urb = NULL;
1736 		/* keep retire_data_urb for delay calculation */
1737 		subs->data_endpoint->retire_data_urb = retire_playback_urb;
1738 		subs->running = 0;
1739 		return 0;
1740 	case SNDRV_PCM_TRIGGER_SUSPEND:
1741 		if (subs->stream->chip->setup_fmt_after_resume_quirk) {
1742 			stop_endpoints(subs);
1743 			subs->need_setup_fmt = true;
1744 			return 0;
1745 		}
1746 		break;
1747 	}
1748 
1749 	return -EINVAL;
1750 }
1751 
1752 static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
1753 					     int cmd)
1754 {
1755 	int err;
1756 	struct snd_usb_substream *subs = substream->runtime->private_data;
1757 
1758 	switch (cmd) {
1759 	case SNDRV_PCM_TRIGGER_START:
1760 		err = start_endpoints(subs);
1761 		if (err < 0)
1762 			return err;
1763 
1764 		subs->data_endpoint->retire_data_urb = retire_capture_urb;
1765 		subs->running = 1;
1766 		return 0;
1767 	case SNDRV_PCM_TRIGGER_STOP:
1768 		stop_endpoints(subs);
1769 		subs->running = 0;
1770 		return 0;
1771 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1772 		subs->data_endpoint->retire_data_urb = NULL;
1773 		subs->running = 0;
1774 		return 0;
1775 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1776 		subs->data_endpoint->retire_data_urb = retire_capture_urb;
1777 		subs->running = 1;
1778 		return 0;
1779 	case SNDRV_PCM_TRIGGER_SUSPEND:
1780 		if (subs->stream->chip->setup_fmt_after_resume_quirk) {
1781 			stop_endpoints(subs);
1782 			subs->need_setup_fmt = true;
1783 			return 0;
1784 		}
1785 		break;
1786 	}
1787 
1788 	return -EINVAL;
1789 }
1790 
1791 static const struct snd_pcm_ops snd_usb_playback_ops = {
1792 	.open =		snd_usb_pcm_open,
1793 	.close =	snd_usb_pcm_close,
1794 	.hw_params =	snd_usb_hw_params,
1795 	.hw_free =	snd_usb_hw_free,
1796 	.prepare =	snd_usb_pcm_prepare,
1797 	.trigger =	snd_usb_substream_playback_trigger,
1798 	.sync_stop =	snd_usb_pcm_sync_stop,
1799 	.pointer =	snd_usb_pcm_pointer,
1800 };
1801 
1802 static const struct snd_pcm_ops snd_usb_capture_ops = {
1803 	.open =		snd_usb_pcm_open,
1804 	.close =	snd_usb_pcm_close,
1805 	.hw_params =	snd_usb_hw_params,
1806 	.hw_free =	snd_usb_hw_free,
1807 	.prepare =	snd_usb_pcm_prepare,
1808 	.trigger =	snd_usb_substream_capture_trigger,
1809 	.sync_stop =	snd_usb_pcm_sync_stop,
1810 	.pointer =	snd_usb_pcm_pointer,
1811 };
1812 
1813 void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
1814 {
1815 	const struct snd_pcm_ops *ops;
1816 
1817 	ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
1818 			&snd_usb_playback_ops : &snd_usb_capture_ops;
1819 	snd_pcm_set_ops(pcm, stream, ops);
1820 }
1821 
1822 void snd_usb_preallocate_buffer(struct snd_usb_substream *subs)
1823 {
1824 	struct snd_pcm *pcm = subs->stream->pcm;
1825 	struct snd_pcm_substream *s = pcm->streams[subs->direction].substream;
1826 	struct device *dev = subs->dev->bus->controller;
1827 
1828 	if (snd_usb_use_vmalloc)
1829 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_VMALLOC,
1830 					   NULL, 0, 0);
1831 	else
1832 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_DEV_SG,
1833 					   dev, 64*1024, 512*1024);
1834 }
1835