xref: /openbmc/linux/sound/usb/pcm.c (revision bd4af432)
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/IIc */
361 		/* MicroBook IIc */
362 		if (altsd->bInterfaceClass == USB_CLASS_AUDIO)
363 			return 0;
364 
365 		/* MicroBook II */
366 		ep = 0x84;
367 		ifnum = 0;
368 		goto add_sync_ep_from_ifnum;
369 	case USB_ID(0x07fd, 0x0008): /* MOTU M Series */
370 		ep = 0x81;
371 		ifnum = 2;
372 		goto add_sync_ep_from_ifnum;
373 	case USB_ID(0x0582, 0x01d8): /* BOSS Katana */
374 		/* BOSS Katana amplifiers do not need quirks */
375 		return 0;
376 	}
377 
378 	if (attr == USB_ENDPOINT_SYNC_ASYNC &&
379 	    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
380 	    altsd->bInterfaceProtocol == 2 &&
381 	    altsd->bNumEndpoints == 1 &&
382 	    USB_ID_VENDOR(subs->stream->chip->usb_id) == 0x0582 /* Roland */ &&
383 	    search_roland_implicit_fb(dev, altsd->bInterfaceNumber + 1,
384 				      altsd->bAlternateSetting,
385 				      &alts, &ep) >= 0) {
386 		goto add_sync_ep;
387 	}
388 
389 	/* No quirk */
390 	return 0;
391 
392 add_sync_ep_from_ifnum:
393 	iface = usb_ifnum_to_if(dev, ifnum);
394 
395 	if (!iface || iface->num_altsetting < 2)
396 		return -EINVAL;
397 
398 	alts = &iface->altsetting[1];
399 
400 add_sync_ep:
401 	subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
402 						   alts, ep, !subs->direction,
403 						   SND_USB_ENDPOINT_TYPE_DATA);
404 	if (!subs->sync_endpoint)
405 		return -EINVAL;
406 
407 	subs->data_endpoint->sync_master = subs->sync_endpoint;
408 
409 	return 1;
410 }
411 
412 static int set_sync_endpoint(struct snd_usb_substream *subs,
413 			     struct audioformat *fmt,
414 			     struct usb_device *dev,
415 			     struct usb_host_interface *alts,
416 			     struct usb_interface_descriptor *altsd)
417 {
418 	int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
419 	unsigned int ep, attr;
420 	bool implicit_fb;
421 	int err;
422 
423 	/* we need a sync pipe in async OUT or adaptive IN mode */
424 	/* check the number of EP, since some devices have broken
425 	 * descriptors which fool us.  if it has only one EP,
426 	 * assume it as adaptive-out or sync-in.
427 	 */
428 	attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
429 
430 	if ((is_playback && (attr != USB_ENDPOINT_SYNC_ASYNC)) ||
431 		(!is_playback && (attr != USB_ENDPOINT_SYNC_ADAPTIVE))) {
432 
433 		/*
434 		 * In these modes the notion of sync_endpoint is irrelevant.
435 		 * Reset pointers to avoid using stale data from previously
436 		 * used settings, e.g. when configuration and endpoints were
437 		 * changed
438 		 */
439 
440 		subs->sync_endpoint = NULL;
441 		subs->data_endpoint->sync_master = NULL;
442 	}
443 
444 	err = set_sync_ep_implicit_fb_quirk(subs, dev, altsd, attr);
445 	if (err < 0)
446 		return err;
447 
448 	/* endpoint set by quirk */
449 	if (err > 0)
450 		return 0;
451 
452 	if (altsd->bNumEndpoints < 2)
453 		return 0;
454 
455 	if ((is_playback && (attr == USB_ENDPOINT_SYNC_SYNC ||
456 			     attr == USB_ENDPOINT_SYNC_ADAPTIVE)) ||
457 	    (!is_playback && attr != USB_ENDPOINT_SYNC_ADAPTIVE))
458 		return 0;
459 
460 	/*
461 	 * In case of illegal SYNC_NONE for OUT endpoint, we keep going to see
462 	 * if we don't find a sync endpoint, as on M-Audio Transit. In case of
463 	 * error fall back to SYNC mode and don't create sync endpoint
464 	 */
465 
466 	/* check sync-pipe endpoint */
467 	/* ... and check descriptor size before accessing bSynchAddress
468 	   because there is a version of the SB Audigy 2 NX firmware lacking
469 	   the audio fields in the endpoint descriptors */
470 	if ((get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) != USB_ENDPOINT_XFER_ISOC ||
471 	    (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
472 	     get_endpoint(alts, 1)->bSynchAddress != 0)) {
473 		dev_err(&dev->dev,
474 			"%d:%d : invalid sync pipe. bmAttributes %02x, bLength %d, bSynchAddress %02x\n",
475 			   fmt->iface, fmt->altsetting,
476 			   get_endpoint(alts, 1)->bmAttributes,
477 			   get_endpoint(alts, 1)->bLength,
478 			   get_endpoint(alts, 1)->bSynchAddress);
479 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
480 			return 0;
481 		return -EINVAL;
482 	}
483 	ep = get_endpoint(alts, 1)->bEndpointAddress;
484 	if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
485 	    get_endpoint(alts, 0)->bSynchAddress != 0 &&
486 	    ((is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
487 	     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
488 		dev_err(&dev->dev,
489 			"%d:%d : invalid sync pipe. is_playback %d, ep %02x, bSynchAddress %02x\n",
490 			   fmt->iface, fmt->altsetting,
491 			   is_playback, ep, get_endpoint(alts, 0)->bSynchAddress);
492 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
493 			return 0;
494 		return -EINVAL;
495 	}
496 
497 	implicit_fb = (get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_USAGE_MASK)
498 			== USB_ENDPOINT_USAGE_IMPLICIT_FB;
499 
500 	subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
501 						   alts, ep, !subs->direction,
502 						   implicit_fb ?
503 							SND_USB_ENDPOINT_TYPE_DATA :
504 							SND_USB_ENDPOINT_TYPE_SYNC);
505 	if (!subs->sync_endpoint) {
506 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
507 			return 0;
508 		return -EINVAL;
509 	}
510 
511 	subs->data_endpoint->sync_master = subs->sync_endpoint;
512 
513 	return 0;
514 }
515 
516 /*
517  * find a matching format and set up the interface
518  */
519 static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
520 {
521 	struct usb_device *dev = subs->dev;
522 	struct usb_host_interface *alts;
523 	struct usb_interface_descriptor *altsd;
524 	struct usb_interface *iface;
525 	int err;
526 
527 	iface = usb_ifnum_to_if(dev, fmt->iface);
528 	if (WARN_ON(!iface))
529 		return -EINVAL;
530 	alts = usb_altnum_to_altsetting(iface, fmt->altsetting);
531 	if (WARN_ON(!alts))
532 		return -EINVAL;
533 	altsd = get_iface_desc(alts);
534 
535 	if (fmt == subs->cur_audiofmt && !subs->need_setup_fmt)
536 		return 0;
537 
538 	/* close the old interface */
539 	if (subs->interface >= 0 && (subs->interface != fmt->iface || subs->need_setup_fmt)) {
540 		if (!subs->stream->chip->keep_iface) {
541 			err = usb_set_interface(subs->dev, subs->interface, 0);
542 			if (err < 0) {
543 				dev_err(&dev->dev,
544 					"%d:%d: return to setting 0 failed (%d)\n",
545 					fmt->iface, fmt->altsetting, err);
546 				return -EIO;
547 			}
548 		}
549 		subs->interface = -1;
550 		subs->altset_idx = 0;
551 	}
552 
553 	if (subs->need_setup_fmt)
554 		subs->need_setup_fmt = false;
555 
556 	/* set interface */
557 	if (iface->cur_altsetting != alts) {
558 		err = snd_usb_select_mode_quirk(subs, fmt);
559 		if (err < 0)
560 			return -EIO;
561 
562 		err = usb_set_interface(dev, fmt->iface, fmt->altsetting);
563 		if (err < 0) {
564 			dev_err(&dev->dev,
565 				"%d:%d: usb_set_interface failed (%d)\n",
566 				fmt->iface, fmt->altsetting, err);
567 			return -EIO;
568 		}
569 		dev_dbg(&dev->dev, "setting usb interface %d:%d\n",
570 			fmt->iface, fmt->altsetting);
571 		snd_usb_set_interface_quirk(dev);
572 	}
573 
574 	subs->interface = fmt->iface;
575 	subs->altset_idx = fmt->altset_idx;
576 	subs->data_endpoint = snd_usb_add_endpoint(subs->stream->chip,
577 						   alts, fmt->endpoint, subs->direction,
578 						   SND_USB_ENDPOINT_TYPE_DATA);
579 
580 	if (!subs->data_endpoint)
581 		return -EINVAL;
582 
583 	err = set_sync_endpoint(subs, fmt, dev, alts, altsd);
584 	if (err < 0)
585 		return err;
586 
587 	err = snd_usb_init_pitch(subs->stream->chip, fmt->iface, alts, fmt);
588 	if (err < 0)
589 		return err;
590 
591 	subs->cur_audiofmt = fmt;
592 
593 	snd_usb_set_format_quirk(subs, fmt);
594 
595 	return 0;
596 }
597 
598 /*
599  * Return the score of matching two audioformats.
600  * Veto the audioformat if:
601  * - It has no channels for some reason.
602  * - Requested PCM format is not supported.
603  * - Requested sample rate is not supported.
604  */
605 static int match_endpoint_audioformats(struct snd_usb_substream *subs,
606 				       struct audioformat *fp,
607 				       struct audioformat *match, int rate,
608 				       snd_pcm_format_t pcm_format)
609 {
610 	int i;
611 	int score = 0;
612 
613 	if (fp->channels < 1) {
614 		dev_dbg(&subs->dev->dev,
615 			"%s: (fmt @%p) no channels\n", __func__, fp);
616 		return 0;
617 	}
618 
619 	if (!(fp->formats & pcm_format_to_bits(pcm_format))) {
620 		dev_dbg(&subs->dev->dev,
621 			"%s: (fmt @%p) no match for format %d\n", __func__,
622 			fp, pcm_format);
623 		return 0;
624 	}
625 
626 	for (i = 0; i < fp->nr_rates; i++) {
627 		if (fp->rate_table[i] == rate) {
628 			score++;
629 			break;
630 		}
631 	}
632 	if (!score) {
633 		dev_dbg(&subs->dev->dev,
634 			"%s: (fmt @%p) no match for rate %d\n", __func__,
635 			fp, rate);
636 		return 0;
637 	}
638 
639 	if (fp->channels == match->channels)
640 		score++;
641 
642 	dev_dbg(&subs->dev->dev,
643 		"%s: (fmt @%p) score %d\n", __func__, fp, score);
644 
645 	return score;
646 }
647 
648 /*
649  * Configure the sync ep using the rate and pcm format of the data ep.
650  */
651 static int configure_sync_endpoint(struct snd_usb_substream *subs)
652 {
653 	int ret;
654 	struct audioformat *fp;
655 	struct audioformat *sync_fp = NULL;
656 	int cur_score = 0;
657 	int sync_period_bytes = subs->period_bytes;
658 	struct snd_usb_substream *sync_subs =
659 		&subs->stream->substream[subs->direction ^ 1];
660 
661 	if (subs->sync_endpoint->type != SND_USB_ENDPOINT_TYPE_DATA ||
662 	    !subs->stream)
663 		return snd_usb_endpoint_set_params(subs->sync_endpoint,
664 						   subs->pcm_format,
665 						   subs->channels,
666 						   subs->period_bytes,
667 						   0, 0,
668 						   subs->cur_rate,
669 						   subs->cur_audiofmt,
670 						   NULL);
671 
672 	/* Try to find the best matching audioformat. */
673 	list_for_each_entry(fp, &sync_subs->fmt_list, list) {
674 		int score = match_endpoint_audioformats(subs,
675 							fp, subs->cur_audiofmt,
676 			subs->cur_rate, subs->pcm_format);
677 
678 		if (score > cur_score) {
679 			sync_fp = fp;
680 			cur_score = score;
681 		}
682 	}
683 
684 	if (unlikely(sync_fp == NULL)) {
685 		dev_err(&subs->dev->dev,
686 			"%s: no valid audioformat for sync ep %x found\n",
687 			__func__, sync_subs->ep_num);
688 		return -EINVAL;
689 	}
690 
691 	/*
692 	 * Recalculate the period bytes if channel number differ between
693 	 * data and sync ep audioformat.
694 	 */
695 	if (sync_fp->channels != subs->channels) {
696 		sync_period_bytes = (subs->period_bytes / subs->channels) *
697 			sync_fp->channels;
698 		dev_dbg(&subs->dev->dev,
699 			"%s: adjusted sync ep period bytes (%d -> %d)\n",
700 			__func__, subs->period_bytes, sync_period_bytes);
701 	}
702 
703 	ret = snd_usb_endpoint_set_params(subs->sync_endpoint,
704 					  subs->pcm_format,
705 					  sync_fp->channels,
706 					  sync_period_bytes,
707 					  0, 0,
708 					  subs->cur_rate,
709 					  sync_fp,
710 					  NULL);
711 
712 	return ret;
713 }
714 
715 /*
716  * configure endpoint params
717  *
718  * called  during initial setup and upon resume
719  */
720 static int configure_endpoint(struct snd_usb_substream *subs)
721 {
722 	int ret;
723 
724 	/* format changed */
725 	stop_endpoints(subs);
726 	sync_pending_stops(subs);
727 	ret = snd_usb_endpoint_set_params(subs->data_endpoint,
728 					  subs->pcm_format,
729 					  subs->channels,
730 					  subs->period_bytes,
731 					  subs->period_frames,
732 					  subs->buffer_periods,
733 					  subs->cur_rate,
734 					  subs->cur_audiofmt,
735 					  subs->sync_endpoint);
736 	if (ret < 0)
737 		return ret;
738 
739 	if (subs->sync_endpoint)
740 		ret = configure_sync_endpoint(subs);
741 
742 	return ret;
743 }
744 
745 static int snd_usb_pcm_change_state(struct snd_usb_substream *subs, int state)
746 {
747 	int ret;
748 
749 	if (!subs->str_pd)
750 		return 0;
751 
752 	ret = snd_usb_power_domain_set(subs->stream->chip, subs->str_pd, state);
753 	if (ret < 0) {
754 		dev_err(&subs->dev->dev,
755 			"Cannot change Power Domain ID: %d to state: %d. Err: %d\n",
756 			subs->str_pd->pd_id, state, ret);
757 		return ret;
758 	}
759 
760 	return 0;
761 }
762 
763 int snd_usb_pcm_suspend(struct snd_usb_stream *as)
764 {
765 	int ret;
766 
767 	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D2);
768 	if (ret < 0)
769 		return ret;
770 
771 	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D2);
772 	if (ret < 0)
773 		return ret;
774 
775 	return 0;
776 }
777 
778 int snd_usb_pcm_resume(struct snd_usb_stream *as)
779 {
780 	int ret;
781 
782 	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D1);
783 	if (ret < 0)
784 		return ret;
785 
786 	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D1);
787 	if (ret < 0)
788 		return ret;
789 
790 	return 0;
791 }
792 
793 /*
794  * hw_params callback
795  *
796  * allocate a buffer and set the given audio format.
797  *
798  * so far we use a physically linear buffer although packetize transfer
799  * doesn't need a continuous area.
800  * if sg buffer is supported on the later version of alsa, we'll follow
801  * that.
802  */
803 static int snd_usb_hw_params(struct snd_pcm_substream *substream,
804 			     struct snd_pcm_hw_params *hw_params)
805 {
806 	struct snd_usb_substream *subs = substream->runtime->private_data;
807 	struct audioformat *fmt;
808 	int ret;
809 
810 	ret = snd_media_start_pipeline(subs);
811 	if (ret)
812 		return ret;
813 
814 	subs->pcm_format = params_format(hw_params);
815 	subs->period_bytes = params_period_bytes(hw_params);
816 	subs->period_frames = params_period_size(hw_params);
817 	subs->buffer_periods = params_periods(hw_params);
818 	subs->channels = params_channels(hw_params);
819 	subs->cur_rate = params_rate(hw_params);
820 
821 	fmt = find_format(subs);
822 	if (!fmt) {
823 		dev_dbg(&subs->dev->dev,
824 			"cannot set format: format = %#x, rate = %d, channels = %d\n",
825 			   subs->pcm_format, subs->cur_rate, subs->channels);
826 		ret = -EINVAL;
827 		goto stop_pipeline;
828 	}
829 
830 	ret = snd_usb_lock_shutdown(subs->stream->chip);
831 	if (ret < 0)
832 		goto stop_pipeline;
833 
834 	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
835 	if (ret < 0)
836 		goto unlock;
837 
838 	ret = set_format(subs, fmt);
839 	if (ret < 0)
840 		goto unlock;
841 
842 	subs->interface = fmt->iface;
843 	subs->altset_idx = fmt->altset_idx;
844 	subs->need_setup_ep = true;
845 
846  unlock:
847 	snd_usb_unlock_shutdown(subs->stream->chip);
848 	if (ret < 0)
849 		goto stop_pipeline;
850 	return ret;
851 
852  stop_pipeline:
853 	snd_media_stop_pipeline(subs);
854 	return ret;
855 }
856 
857 /*
858  * hw_free callback
859  *
860  * reset the audio format and release the buffer
861  */
862 static int snd_usb_hw_free(struct snd_pcm_substream *substream)
863 {
864 	struct snd_usb_substream *subs = substream->runtime->private_data;
865 
866 	snd_media_stop_pipeline(subs);
867 	subs->cur_audiofmt = NULL;
868 	subs->cur_rate = 0;
869 	subs->period_bytes = 0;
870 	if (!snd_usb_lock_shutdown(subs->stream->chip)) {
871 		stop_endpoints(subs);
872 		sync_pending_stops(subs);
873 		snd_usb_endpoint_deactivate(subs->sync_endpoint);
874 		snd_usb_endpoint_deactivate(subs->data_endpoint);
875 		snd_usb_unlock_shutdown(subs->stream->chip);
876 	}
877 
878 	return 0;
879 }
880 
881 /*
882  * prepare callback
883  *
884  * only a few subtle things...
885  */
886 static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
887 {
888 	struct snd_pcm_runtime *runtime = substream->runtime;
889 	struct snd_usb_substream *subs = runtime->private_data;
890 	struct usb_host_interface *alts;
891 	struct usb_interface *iface;
892 	int ret;
893 
894 	if (! subs->cur_audiofmt) {
895 		dev_err(&subs->dev->dev, "no format is specified!\n");
896 		return -ENXIO;
897 	}
898 
899 	ret = snd_usb_lock_shutdown(subs->stream->chip);
900 	if (ret < 0)
901 		return ret;
902 	if (snd_BUG_ON(!subs->data_endpoint)) {
903 		ret = -EIO;
904 		goto unlock;
905 	}
906 
907 	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
908 	if (ret < 0)
909 		goto unlock;
910 
911 	ret = set_format(subs, subs->cur_audiofmt);
912 	if (ret < 0)
913 		goto unlock;
914 
915 	if (subs->need_setup_ep) {
916 
917 		iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
918 		alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
919 		ret = snd_usb_init_sample_rate(subs->stream->chip,
920 					       subs->cur_audiofmt->iface,
921 					       alts,
922 					       subs->cur_audiofmt,
923 					       subs->cur_rate);
924 		if (ret < 0)
925 			goto unlock;
926 
927 		ret = configure_endpoint(subs);
928 		if (ret < 0)
929 			goto unlock;
930 		subs->need_setup_ep = false;
931 	}
932 
933 	/* some unit conversions in runtime */
934 	subs->data_endpoint->maxframesize =
935 		bytes_to_frames(runtime, subs->data_endpoint->maxpacksize);
936 	subs->data_endpoint->curframesize =
937 		bytes_to_frames(runtime, subs->data_endpoint->curpacksize);
938 
939 	/* reset the pointer */
940 	subs->hwptr_done = 0;
941 	subs->transfer_done = 0;
942 	subs->last_delay = 0;
943 	subs->last_frame_number = 0;
944 	runtime->delay = 0;
945 
946 	/* for playback, submit the URBs now; otherwise, the first hwptr_done
947 	 * updates for all URBs would happen at the same time when starting */
948 	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK)
949 		ret = start_endpoints(subs);
950 
951  unlock:
952 	snd_usb_unlock_shutdown(subs->stream->chip);
953 	return ret;
954 }
955 
956 static const struct snd_pcm_hardware snd_usb_hardware =
957 {
958 	.info =			SNDRV_PCM_INFO_MMAP |
959 				SNDRV_PCM_INFO_MMAP_VALID |
960 				SNDRV_PCM_INFO_BATCH |
961 				SNDRV_PCM_INFO_INTERLEAVED |
962 				SNDRV_PCM_INFO_BLOCK_TRANSFER |
963 				SNDRV_PCM_INFO_PAUSE,
964 	.buffer_bytes_max =	1024 * 1024,
965 	.period_bytes_min =	64,
966 	.period_bytes_max =	512 * 1024,
967 	.periods_min =		2,
968 	.periods_max =		1024,
969 };
970 
971 static int hw_check_valid_format(struct snd_usb_substream *subs,
972 				 struct snd_pcm_hw_params *params,
973 				 struct audioformat *fp)
974 {
975 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
976 	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
977 	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
978 	struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
979 	struct snd_mask check_fmts;
980 	unsigned int ptime;
981 
982 	/* check the format */
983 	snd_mask_none(&check_fmts);
984 	check_fmts.bits[0] = (u32)fp->formats;
985 	check_fmts.bits[1] = (u32)(fp->formats >> 32);
986 	snd_mask_intersect(&check_fmts, fmts);
987 	if (snd_mask_empty(&check_fmts)) {
988 		hwc_debug("   > check: no supported format %d\n", fp->format);
989 		return 0;
990 	}
991 	/* check the channels */
992 	if (fp->channels < ct->min || fp->channels > ct->max) {
993 		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
994 		return 0;
995 	}
996 	/* check the rate is within the range */
997 	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
998 		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
999 		return 0;
1000 	}
1001 	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
1002 		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
1003 		return 0;
1004 	}
1005 	/* check whether the period time is >= the data packet interval */
1006 	if (subs->speed != USB_SPEED_FULL) {
1007 		ptime = 125 * (1 << fp->datainterval);
1008 		if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
1009 			hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
1010 			return 0;
1011 		}
1012 	}
1013 	return 1;
1014 }
1015 
1016 static int hw_rule_rate(struct snd_pcm_hw_params *params,
1017 			struct snd_pcm_hw_rule *rule)
1018 {
1019 	struct snd_usb_substream *subs = rule->private;
1020 	struct audioformat *fp;
1021 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
1022 	unsigned int rmin, rmax;
1023 	int changed;
1024 
1025 	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
1026 	changed = 0;
1027 	rmin = rmax = 0;
1028 	list_for_each_entry(fp, &subs->fmt_list, list) {
1029 		if (!hw_check_valid_format(subs, params, fp))
1030 			continue;
1031 		if (changed++) {
1032 			if (rmin > fp->rate_min)
1033 				rmin = fp->rate_min;
1034 			if (rmax < fp->rate_max)
1035 				rmax = fp->rate_max;
1036 		} else {
1037 			rmin = fp->rate_min;
1038 			rmax = fp->rate_max;
1039 		}
1040 	}
1041 
1042 	if (!changed) {
1043 		hwc_debug("  --> get empty\n");
1044 		it->empty = 1;
1045 		return -EINVAL;
1046 	}
1047 
1048 	changed = 0;
1049 	if (it->min < rmin) {
1050 		it->min = rmin;
1051 		it->openmin = 0;
1052 		changed = 1;
1053 	}
1054 	if (it->max > rmax) {
1055 		it->max = rmax;
1056 		it->openmax = 0;
1057 		changed = 1;
1058 	}
1059 	if (snd_interval_checkempty(it)) {
1060 		it->empty = 1;
1061 		return -EINVAL;
1062 	}
1063 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
1064 	return changed;
1065 }
1066 
1067 
1068 static int hw_rule_channels(struct snd_pcm_hw_params *params,
1069 			    struct snd_pcm_hw_rule *rule)
1070 {
1071 	struct snd_usb_substream *subs = rule->private;
1072 	struct audioformat *fp;
1073 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
1074 	unsigned int rmin, rmax;
1075 	int changed;
1076 
1077 	hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
1078 	changed = 0;
1079 	rmin = rmax = 0;
1080 	list_for_each_entry(fp, &subs->fmt_list, list) {
1081 		if (!hw_check_valid_format(subs, params, fp))
1082 			continue;
1083 		if (changed++) {
1084 			if (rmin > fp->channels)
1085 				rmin = fp->channels;
1086 			if (rmax < fp->channels)
1087 				rmax = fp->channels;
1088 		} else {
1089 			rmin = fp->channels;
1090 			rmax = fp->channels;
1091 		}
1092 	}
1093 
1094 	if (!changed) {
1095 		hwc_debug("  --> get empty\n");
1096 		it->empty = 1;
1097 		return -EINVAL;
1098 	}
1099 
1100 	changed = 0;
1101 	if (it->min < rmin) {
1102 		it->min = rmin;
1103 		it->openmin = 0;
1104 		changed = 1;
1105 	}
1106 	if (it->max > rmax) {
1107 		it->max = rmax;
1108 		it->openmax = 0;
1109 		changed = 1;
1110 	}
1111 	if (snd_interval_checkempty(it)) {
1112 		it->empty = 1;
1113 		return -EINVAL;
1114 	}
1115 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
1116 	return changed;
1117 }
1118 
1119 static int hw_rule_format(struct snd_pcm_hw_params *params,
1120 			  struct snd_pcm_hw_rule *rule)
1121 {
1122 	struct snd_usb_substream *subs = rule->private;
1123 	struct audioformat *fp;
1124 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
1125 	u64 fbits;
1126 	u32 oldbits[2];
1127 	int changed;
1128 
1129 	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
1130 	fbits = 0;
1131 	list_for_each_entry(fp, &subs->fmt_list, list) {
1132 		if (!hw_check_valid_format(subs, params, fp))
1133 			continue;
1134 		fbits |= fp->formats;
1135 	}
1136 
1137 	oldbits[0] = fmt->bits[0];
1138 	oldbits[1] = fmt->bits[1];
1139 	fmt->bits[0] &= (u32)fbits;
1140 	fmt->bits[1] &= (u32)(fbits >> 32);
1141 	if (!fmt->bits[0] && !fmt->bits[1]) {
1142 		hwc_debug("  --> get empty\n");
1143 		return -EINVAL;
1144 	}
1145 	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
1146 	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
1147 	return changed;
1148 }
1149 
1150 static int hw_rule_period_time(struct snd_pcm_hw_params *params,
1151 			       struct snd_pcm_hw_rule *rule)
1152 {
1153 	struct snd_usb_substream *subs = rule->private;
1154 	struct audioformat *fp;
1155 	struct snd_interval *it;
1156 	unsigned char min_datainterval;
1157 	unsigned int pmin;
1158 	int changed;
1159 
1160 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
1161 	hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
1162 	min_datainterval = 0xff;
1163 	list_for_each_entry(fp, &subs->fmt_list, list) {
1164 		if (!hw_check_valid_format(subs, params, fp))
1165 			continue;
1166 		min_datainterval = min(min_datainterval, fp->datainterval);
1167 	}
1168 	if (min_datainterval == 0xff) {
1169 		hwc_debug("  --> get empty\n");
1170 		it->empty = 1;
1171 		return -EINVAL;
1172 	}
1173 	pmin = 125 * (1 << min_datainterval);
1174 	changed = 0;
1175 	if (it->min < pmin) {
1176 		it->min = pmin;
1177 		it->openmin = 0;
1178 		changed = 1;
1179 	}
1180 	if (snd_interval_checkempty(it)) {
1181 		it->empty = 1;
1182 		return -EINVAL;
1183 	}
1184 	hwc_debug("  --> (%u,%u) (changed = %d)\n", it->min, it->max, changed);
1185 	return changed;
1186 }
1187 
1188 /*
1189  *  If the device supports unusual bit rates, does the request meet these?
1190  */
1191 static int snd_usb_pcm_check_knot(struct snd_pcm_runtime *runtime,
1192 				  struct snd_usb_substream *subs)
1193 {
1194 	struct audioformat *fp;
1195 	int *rate_list;
1196 	int count = 0, needs_knot = 0;
1197 	int err;
1198 
1199 	kfree(subs->rate_list.list);
1200 	subs->rate_list.list = NULL;
1201 
1202 	list_for_each_entry(fp, &subs->fmt_list, list) {
1203 		if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)
1204 			return 0;
1205 		count += fp->nr_rates;
1206 		if (fp->rates & SNDRV_PCM_RATE_KNOT)
1207 			needs_knot = 1;
1208 	}
1209 	if (!needs_knot)
1210 		return 0;
1211 
1212 	subs->rate_list.list = rate_list =
1213 		kmalloc_array(count, sizeof(int), GFP_KERNEL);
1214 	if (!subs->rate_list.list)
1215 		return -ENOMEM;
1216 	subs->rate_list.count = count;
1217 	subs->rate_list.mask = 0;
1218 	count = 0;
1219 	list_for_each_entry(fp, &subs->fmt_list, list) {
1220 		int i;
1221 		for (i = 0; i < fp->nr_rates; i++)
1222 			rate_list[count++] = fp->rate_table[i];
1223 	}
1224 	err = snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1225 					 &subs->rate_list);
1226 	if (err < 0)
1227 		return err;
1228 
1229 	return 0;
1230 }
1231 
1232 
1233 /*
1234  * set up the runtime hardware information.
1235  */
1236 
1237 static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
1238 {
1239 	struct audioformat *fp;
1240 	unsigned int pt, ptmin;
1241 	int param_period_time_if_needed;
1242 	int err;
1243 
1244 	runtime->hw.formats = subs->formats;
1245 
1246 	runtime->hw.rate_min = 0x7fffffff;
1247 	runtime->hw.rate_max = 0;
1248 	runtime->hw.channels_min = 256;
1249 	runtime->hw.channels_max = 0;
1250 	runtime->hw.rates = 0;
1251 	ptmin = UINT_MAX;
1252 	/* check min/max rates and channels */
1253 	list_for_each_entry(fp, &subs->fmt_list, list) {
1254 		runtime->hw.rates |= fp->rates;
1255 		if (runtime->hw.rate_min > fp->rate_min)
1256 			runtime->hw.rate_min = fp->rate_min;
1257 		if (runtime->hw.rate_max < fp->rate_max)
1258 			runtime->hw.rate_max = fp->rate_max;
1259 		if (runtime->hw.channels_min > fp->channels)
1260 			runtime->hw.channels_min = fp->channels;
1261 		if (runtime->hw.channels_max < fp->channels)
1262 			runtime->hw.channels_max = fp->channels;
1263 		if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
1264 			/* FIXME: there might be more than one audio formats... */
1265 			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
1266 				fp->frame_size;
1267 		}
1268 		pt = 125 * (1 << fp->datainterval);
1269 		ptmin = min(ptmin, pt);
1270 	}
1271 
1272 	param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
1273 	if (subs->speed == USB_SPEED_FULL)
1274 		/* full speed devices have fixed data packet interval */
1275 		ptmin = 1000;
1276 	if (ptmin == 1000)
1277 		/* if period time doesn't go below 1 ms, no rules needed */
1278 		param_period_time_if_needed = -1;
1279 
1280 	err = snd_pcm_hw_constraint_minmax(runtime,
1281 					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1282 					   ptmin, UINT_MAX);
1283 	if (err < 0)
1284 		return err;
1285 
1286 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1287 				  hw_rule_rate, subs,
1288 				  SNDRV_PCM_HW_PARAM_FORMAT,
1289 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1290 				  param_period_time_if_needed,
1291 				  -1);
1292 	if (err < 0)
1293 		return err;
1294 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
1295 				  hw_rule_channels, subs,
1296 				  SNDRV_PCM_HW_PARAM_FORMAT,
1297 				  SNDRV_PCM_HW_PARAM_RATE,
1298 				  param_period_time_if_needed,
1299 				  -1);
1300 	if (err < 0)
1301 		return err;
1302 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1303 				  hw_rule_format, subs,
1304 				  SNDRV_PCM_HW_PARAM_RATE,
1305 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1306 				  param_period_time_if_needed,
1307 				  -1);
1308 	if (err < 0)
1309 		return err;
1310 	if (param_period_time_if_needed >= 0) {
1311 		err = snd_pcm_hw_rule_add(runtime, 0,
1312 					  SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1313 					  hw_rule_period_time, subs,
1314 					  SNDRV_PCM_HW_PARAM_FORMAT,
1315 					  SNDRV_PCM_HW_PARAM_CHANNELS,
1316 					  SNDRV_PCM_HW_PARAM_RATE,
1317 					  -1);
1318 		if (err < 0)
1319 			return err;
1320 	}
1321 	err = snd_usb_pcm_check_knot(runtime, subs);
1322 	if (err < 0)
1323 		return err;
1324 
1325 	return snd_usb_autoresume(subs->stream->chip);
1326 }
1327 
1328 static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
1329 {
1330 	int direction = substream->stream;
1331 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1332 	struct snd_pcm_runtime *runtime = substream->runtime;
1333 	struct snd_usb_substream *subs = &as->substream[direction];
1334 	int ret;
1335 
1336 	subs->interface = -1;
1337 	subs->altset_idx = 0;
1338 	runtime->hw = snd_usb_hardware;
1339 	runtime->private_data = subs;
1340 	subs->pcm_substream = substream;
1341 	/* runtime PM is also done there */
1342 
1343 	/* initialize DSD/DOP context */
1344 	subs->dsd_dop.byte_idx = 0;
1345 	subs->dsd_dop.channel = 0;
1346 	subs->dsd_dop.marker = 1;
1347 
1348 	ret = setup_hw_info(runtime, subs);
1349 	if (ret == 0) {
1350 		ret = snd_media_stream_init(subs, as->pcm, direction);
1351 		if (ret)
1352 			snd_usb_autosuspend(subs->stream->chip);
1353 	}
1354 	return ret;
1355 }
1356 
1357 static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
1358 {
1359 	int direction = substream->stream;
1360 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1361 	struct snd_usb_substream *subs = &as->substream[direction];
1362 	int ret;
1363 
1364 	snd_media_stop_pipeline(subs);
1365 
1366 	if (!as->chip->keep_iface &&
1367 	    subs->interface >= 0 &&
1368 	    !snd_usb_lock_shutdown(subs->stream->chip)) {
1369 		usb_set_interface(subs->dev, subs->interface, 0);
1370 		subs->interface = -1;
1371 		ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
1372 		snd_usb_unlock_shutdown(subs->stream->chip);
1373 		if (ret < 0)
1374 			return ret;
1375 	}
1376 
1377 	subs->pcm_substream = NULL;
1378 	snd_usb_autosuspend(subs->stream->chip);
1379 
1380 	return 0;
1381 }
1382 
1383 /* Since a URB can handle only a single linear buffer, we must use double
1384  * buffering when the data to be transferred overflows the buffer boundary.
1385  * To avoid inconsistencies when updating hwptr_done, we use double buffering
1386  * for all URBs.
1387  */
1388 static void retire_capture_urb(struct snd_usb_substream *subs,
1389 			       struct urb *urb)
1390 {
1391 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1392 	unsigned int stride, frames, bytes, oldptr;
1393 	int i, period_elapsed = 0;
1394 	unsigned long flags;
1395 	unsigned char *cp;
1396 	int current_frame_number;
1397 
1398 	/* read frame number here, update pointer in critical section */
1399 	current_frame_number = usb_get_current_frame_number(subs->dev);
1400 
1401 	stride = runtime->frame_bits >> 3;
1402 
1403 	for (i = 0; i < urb->number_of_packets; i++) {
1404 		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;
1405 		if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
1406 			dev_dbg(&subs->dev->dev, "frame %d active: %d\n",
1407 				i, urb->iso_frame_desc[i].status);
1408 			// continue;
1409 		}
1410 		bytes = urb->iso_frame_desc[i].actual_length;
1411 		frames = bytes / stride;
1412 		if (!subs->txfr_quirk)
1413 			bytes = frames * stride;
1414 		if (bytes % (runtime->sample_bits >> 3) != 0) {
1415 			int oldbytes = bytes;
1416 			bytes = frames * stride;
1417 			dev_warn_ratelimited(&subs->dev->dev,
1418 				 "Corrected urb data len. %d->%d\n",
1419 							oldbytes, bytes);
1420 		}
1421 		/* update the current pointer */
1422 		spin_lock_irqsave(&subs->lock, flags);
1423 		oldptr = subs->hwptr_done;
1424 		subs->hwptr_done += bytes;
1425 		if (subs->hwptr_done >= runtime->buffer_size * stride)
1426 			subs->hwptr_done -= runtime->buffer_size * stride;
1427 		frames = (bytes + (oldptr % stride)) / stride;
1428 		subs->transfer_done += frames;
1429 		if (subs->transfer_done >= runtime->period_size) {
1430 			subs->transfer_done -= runtime->period_size;
1431 			period_elapsed = 1;
1432 		}
1433 		/* capture delay is by construction limited to one URB,
1434 		 * reset delays here
1435 		 */
1436 		runtime->delay = subs->last_delay = 0;
1437 
1438 		/* realign last_frame_number */
1439 		subs->last_frame_number = current_frame_number;
1440 		subs->last_frame_number &= 0xFF; /* keep 8 LSBs */
1441 
1442 		spin_unlock_irqrestore(&subs->lock, flags);
1443 		/* copy a data chunk */
1444 		if (oldptr + bytes > runtime->buffer_size * stride) {
1445 			unsigned int bytes1 =
1446 					runtime->buffer_size * stride - oldptr;
1447 			memcpy(runtime->dma_area + oldptr, cp, bytes1);
1448 			memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
1449 		} else {
1450 			memcpy(runtime->dma_area + oldptr, cp, bytes);
1451 		}
1452 	}
1453 
1454 	if (period_elapsed)
1455 		snd_pcm_period_elapsed(subs->pcm_substream);
1456 }
1457 
1458 static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
1459 					     struct urb *urb, unsigned int bytes)
1460 {
1461 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1462 	unsigned int stride = runtime->frame_bits >> 3;
1463 	unsigned int dst_idx = 0;
1464 	unsigned int src_idx = subs->hwptr_done;
1465 	unsigned int wrap = runtime->buffer_size * stride;
1466 	u8 *dst = urb->transfer_buffer;
1467 	u8 *src = runtime->dma_area;
1468 	u8 marker[] = { 0x05, 0xfa };
1469 
1470 	/*
1471 	 * The DSP DOP format defines a way to transport DSD samples over
1472 	 * normal PCM data endpoints. It requires stuffing of marker bytes
1473 	 * (0x05 and 0xfa, alternating per sample frame), and then expects
1474 	 * 2 additional bytes of actual payload. The whole frame is stored
1475 	 * LSB.
1476 	 *
1477 	 * Hence, for a stereo transport, the buffer layout looks like this,
1478 	 * where L refers to left channel samples and R to right.
1479 	 *
1480 	 *   L1 L2 0x05   R1 R2 0x05   L3 L4 0xfa  R3 R4 0xfa
1481 	 *   L5 L6 0x05   R5 R6 0x05   L7 L8 0xfa  R7 R8 0xfa
1482 	 *   .....
1483 	 *
1484 	 */
1485 
1486 	while (bytes--) {
1487 		if (++subs->dsd_dop.byte_idx == 3) {
1488 			/* frame boundary? */
1489 			dst[dst_idx++] = marker[subs->dsd_dop.marker];
1490 			src_idx += 2;
1491 			subs->dsd_dop.byte_idx = 0;
1492 
1493 			if (++subs->dsd_dop.channel % runtime->channels == 0) {
1494 				/* alternate the marker */
1495 				subs->dsd_dop.marker++;
1496 				subs->dsd_dop.marker %= ARRAY_SIZE(marker);
1497 				subs->dsd_dop.channel = 0;
1498 			}
1499 		} else {
1500 			/* stuff the DSD payload */
1501 			int idx = (src_idx + subs->dsd_dop.byte_idx - 1) % wrap;
1502 
1503 			if (subs->cur_audiofmt->dsd_bitrev)
1504 				dst[dst_idx++] = bitrev8(src[idx]);
1505 			else
1506 				dst[dst_idx++] = src[idx];
1507 
1508 			subs->hwptr_done++;
1509 		}
1510 	}
1511 	if (subs->hwptr_done >= runtime->buffer_size * stride)
1512 		subs->hwptr_done -= runtime->buffer_size * stride;
1513 }
1514 
1515 static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
1516 			int offset, int stride, unsigned int bytes)
1517 {
1518 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1519 
1520 	if (subs->hwptr_done + bytes > runtime->buffer_size * stride) {
1521 		/* err, the transferred area goes over buffer boundary. */
1522 		unsigned int bytes1 =
1523 			runtime->buffer_size * stride - subs->hwptr_done;
1524 		memcpy(urb->transfer_buffer + offset,
1525 		       runtime->dma_area + subs->hwptr_done, bytes1);
1526 		memcpy(urb->transfer_buffer + offset + bytes1,
1527 		       runtime->dma_area, bytes - bytes1);
1528 	} else {
1529 		memcpy(urb->transfer_buffer + offset,
1530 		       runtime->dma_area + subs->hwptr_done, bytes);
1531 	}
1532 	subs->hwptr_done += bytes;
1533 	if (subs->hwptr_done >= runtime->buffer_size * stride)
1534 		subs->hwptr_done -= runtime->buffer_size * stride;
1535 }
1536 
1537 static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
1538 				      struct urb *urb, int stride,
1539 				      unsigned int bytes)
1540 {
1541 	__le32 packet_length;
1542 	int i;
1543 
1544 	/* Put __le32 length descriptor at start of each packet. */
1545 	for (i = 0; i < urb->number_of_packets; i++) {
1546 		unsigned int length = urb->iso_frame_desc[i].length;
1547 		unsigned int offset = urb->iso_frame_desc[i].offset;
1548 
1549 		packet_length = cpu_to_le32(length);
1550 		offset += i * sizeof(packet_length);
1551 		urb->iso_frame_desc[i].offset = offset;
1552 		urb->iso_frame_desc[i].length += sizeof(packet_length);
1553 		memcpy(urb->transfer_buffer + offset,
1554 		       &packet_length, sizeof(packet_length));
1555 		copy_to_urb(subs, urb, offset + sizeof(packet_length),
1556 			    stride, length);
1557 	}
1558 	/* Adjust transfer size accordingly. */
1559 	bytes += urb->number_of_packets * sizeof(packet_length);
1560 	return bytes;
1561 }
1562 
1563 static void prepare_playback_urb(struct snd_usb_substream *subs,
1564 				 struct urb *urb)
1565 {
1566 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1567 	struct snd_usb_endpoint *ep = subs->data_endpoint;
1568 	struct snd_urb_ctx *ctx = urb->context;
1569 	unsigned int counts, frames, bytes;
1570 	int i, stride, period_elapsed = 0;
1571 	unsigned long flags;
1572 
1573 	stride = runtime->frame_bits >> 3;
1574 
1575 	frames = 0;
1576 	urb->number_of_packets = 0;
1577 	spin_lock_irqsave(&subs->lock, flags);
1578 	subs->frame_limit += ep->max_urb_frames;
1579 	for (i = 0; i < ctx->packets; i++) {
1580 		if (ctx->packet_size[i])
1581 			counts = ctx->packet_size[i];
1582 		else
1583 			counts = snd_usb_endpoint_next_packet_size(ep);
1584 
1585 		/* set up descriptor */
1586 		urb->iso_frame_desc[i].offset = frames * ep->stride;
1587 		urb->iso_frame_desc[i].length = counts * ep->stride;
1588 		frames += counts;
1589 		urb->number_of_packets++;
1590 		subs->transfer_done += counts;
1591 		if (subs->transfer_done >= runtime->period_size) {
1592 			subs->transfer_done -= runtime->period_size;
1593 			subs->frame_limit = 0;
1594 			period_elapsed = 1;
1595 			if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
1596 				if (subs->transfer_done > 0) {
1597 					/* FIXME: fill-max mode is not
1598 					 * supported yet */
1599 					frames -= subs->transfer_done;
1600 					counts -= subs->transfer_done;
1601 					urb->iso_frame_desc[i].length =
1602 						counts * ep->stride;
1603 					subs->transfer_done = 0;
1604 				}
1605 				i++;
1606 				if (i < ctx->packets) {
1607 					/* add a transfer delimiter */
1608 					urb->iso_frame_desc[i].offset =
1609 						frames * ep->stride;
1610 					urb->iso_frame_desc[i].length = 0;
1611 					urb->number_of_packets++;
1612 				}
1613 				break;
1614 			}
1615 		}
1616 		/* finish at the period boundary or after enough frames */
1617 		if ((period_elapsed ||
1618 				subs->transfer_done >= subs->frame_limit) &&
1619 		    !snd_usb_endpoint_implicit_feedback_sink(ep))
1620 			break;
1621 	}
1622 	bytes = frames * ep->stride;
1623 
1624 	if (unlikely(subs->pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
1625 		     subs->cur_audiofmt->dsd_dop)) {
1626 		fill_playback_urb_dsd_dop(subs, urb, bytes);
1627 	} else if (unlikely(subs->pcm_format == SNDRV_PCM_FORMAT_DSD_U8 &&
1628 			   subs->cur_audiofmt->dsd_bitrev)) {
1629 		/* bit-reverse the bytes */
1630 		u8 *buf = urb->transfer_buffer;
1631 		for (i = 0; i < bytes; i++) {
1632 			int idx = (subs->hwptr_done + i)
1633 				% (runtime->buffer_size * stride);
1634 			buf[i] = bitrev8(runtime->dma_area[idx]);
1635 		}
1636 
1637 		subs->hwptr_done += bytes;
1638 		if (subs->hwptr_done >= runtime->buffer_size * stride)
1639 			subs->hwptr_done -= runtime->buffer_size * stride;
1640 	} else {
1641 		/* usual PCM */
1642 		if (!subs->tx_length_quirk)
1643 			copy_to_urb(subs, urb, 0, stride, bytes);
1644 		else
1645 			bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
1646 			/* bytes is now amount of outgoing data */
1647 	}
1648 
1649 	/* update delay with exact number of samples queued */
1650 	runtime->delay = subs->last_delay;
1651 	runtime->delay += frames;
1652 	subs->last_delay = runtime->delay;
1653 
1654 	/* realign last_frame_number */
1655 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1656 	subs->last_frame_number &= 0xFF; /* keep 8 LSBs */
1657 
1658 	if (subs->trigger_tstamp_pending_update) {
1659 		/* this is the first actual URB submitted,
1660 		 * update trigger timestamp to reflect actual start time
1661 		 */
1662 		snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
1663 		subs->trigger_tstamp_pending_update = false;
1664 	}
1665 
1666 	spin_unlock_irqrestore(&subs->lock, flags);
1667 	urb->transfer_buffer_length = bytes;
1668 	if (period_elapsed)
1669 		snd_pcm_period_elapsed(subs->pcm_substream);
1670 }
1671 
1672 /*
1673  * process after playback data complete
1674  * - decrease the delay count again
1675  */
1676 static void retire_playback_urb(struct snd_usb_substream *subs,
1677 			       struct urb *urb)
1678 {
1679 	unsigned long flags;
1680 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1681 	struct snd_usb_endpoint *ep = subs->data_endpoint;
1682 	int processed = urb->transfer_buffer_length / ep->stride;
1683 	int est_delay;
1684 
1685 	/* ignore the delay accounting when procssed=0 is given, i.e.
1686 	 * silent payloads are procssed before handling the actual data
1687 	 */
1688 	if (!processed)
1689 		return;
1690 
1691 	spin_lock_irqsave(&subs->lock, flags);
1692 	if (!subs->last_delay)
1693 		goto out; /* short path */
1694 
1695 	est_delay = snd_usb_pcm_delay(subs, runtime->rate);
1696 	/* update delay with exact number of samples played */
1697 	if (processed > subs->last_delay)
1698 		subs->last_delay = 0;
1699 	else
1700 		subs->last_delay -= processed;
1701 	runtime->delay = subs->last_delay;
1702 
1703 	/*
1704 	 * Report when delay estimate is off by more than 2ms.
1705 	 * The error should be lower than 2ms since the estimate relies
1706 	 * on two reads of a counter updated every ms.
1707 	 */
1708 	if (abs(est_delay - subs->last_delay) * 1000 > runtime->rate * 2)
1709 		dev_dbg_ratelimited(&subs->dev->dev,
1710 			"delay: estimated %d, actual %d\n",
1711 			est_delay, subs->last_delay);
1712 
1713 	if (!subs->running) {
1714 		/* update last_frame_number for delay counting here since
1715 		 * prepare_playback_urb won't be called during pause
1716 		 */
1717 		subs->last_frame_number =
1718 			usb_get_current_frame_number(subs->dev) & 0xff;
1719 	}
1720 
1721  out:
1722 	spin_unlock_irqrestore(&subs->lock, flags);
1723 }
1724 
1725 static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
1726 					      int cmd)
1727 {
1728 	struct snd_usb_substream *subs = substream->runtime->private_data;
1729 
1730 	switch (cmd) {
1731 	case SNDRV_PCM_TRIGGER_START:
1732 		subs->trigger_tstamp_pending_update = true;
1733 		/* fall through */
1734 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1735 		subs->data_endpoint->prepare_data_urb = prepare_playback_urb;
1736 		subs->data_endpoint->retire_data_urb = retire_playback_urb;
1737 		subs->running = 1;
1738 		return 0;
1739 	case SNDRV_PCM_TRIGGER_STOP:
1740 		stop_endpoints(subs);
1741 		subs->running = 0;
1742 		return 0;
1743 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1744 		subs->data_endpoint->prepare_data_urb = NULL;
1745 		/* keep retire_data_urb for delay calculation */
1746 		subs->data_endpoint->retire_data_urb = retire_playback_urb;
1747 		subs->running = 0;
1748 		return 0;
1749 	case SNDRV_PCM_TRIGGER_SUSPEND:
1750 		if (subs->stream->chip->setup_fmt_after_resume_quirk) {
1751 			stop_endpoints(subs);
1752 			subs->need_setup_fmt = true;
1753 			return 0;
1754 		}
1755 		break;
1756 	}
1757 
1758 	return -EINVAL;
1759 }
1760 
1761 static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
1762 					     int cmd)
1763 {
1764 	int err;
1765 	struct snd_usb_substream *subs = substream->runtime->private_data;
1766 
1767 	switch (cmd) {
1768 	case SNDRV_PCM_TRIGGER_START:
1769 		err = start_endpoints(subs);
1770 		if (err < 0)
1771 			return err;
1772 
1773 		subs->data_endpoint->retire_data_urb = retire_capture_urb;
1774 		subs->running = 1;
1775 		return 0;
1776 	case SNDRV_PCM_TRIGGER_STOP:
1777 		stop_endpoints(subs);
1778 		subs->running = 0;
1779 		return 0;
1780 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1781 		subs->data_endpoint->retire_data_urb = NULL;
1782 		subs->running = 0;
1783 		return 0;
1784 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1785 		subs->data_endpoint->retire_data_urb = retire_capture_urb;
1786 		subs->running = 1;
1787 		return 0;
1788 	case SNDRV_PCM_TRIGGER_SUSPEND:
1789 		if (subs->stream->chip->setup_fmt_after_resume_quirk) {
1790 			stop_endpoints(subs);
1791 			subs->need_setup_fmt = true;
1792 			return 0;
1793 		}
1794 		break;
1795 	}
1796 
1797 	return -EINVAL;
1798 }
1799 
1800 static const struct snd_pcm_ops snd_usb_playback_ops = {
1801 	.open =		snd_usb_pcm_open,
1802 	.close =	snd_usb_pcm_close,
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 	.sync_stop =	snd_usb_pcm_sync_stop,
1808 	.pointer =	snd_usb_pcm_pointer,
1809 };
1810 
1811 static const struct snd_pcm_ops snd_usb_capture_ops = {
1812 	.open =		snd_usb_pcm_open,
1813 	.close =	snd_usb_pcm_close,
1814 	.hw_params =	snd_usb_hw_params,
1815 	.hw_free =	snd_usb_hw_free,
1816 	.prepare =	snd_usb_pcm_prepare,
1817 	.trigger =	snd_usb_substream_capture_trigger,
1818 	.sync_stop =	snd_usb_pcm_sync_stop,
1819 	.pointer =	snd_usb_pcm_pointer,
1820 };
1821 
1822 void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
1823 {
1824 	const struct snd_pcm_ops *ops;
1825 
1826 	ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
1827 			&snd_usb_playback_ops : &snd_usb_capture_ops;
1828 	snd_pcm_set_ops(pcm, stream, ops);
1829 }
1830 
1831 void snd_usb_preallocate_buffer(struct snd_usb_substream *subs)
1832 {
1833 	struct snd_pcm *pcm = subs->stream->pcm;
1834 	struct snd_pcm_substream *s = pcm->streams[subs->direction].substream;
1835 	struct device *dev = subs->dev->bus->controller;
1836 
1837 	if (snd_usb_use_vmalloc)
1838 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_VMALLOC,
1839 					   NULL, 0, 0);
1840 	else
1841 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_DEV_SG,
1842 					   dev, 64*1024, 512*1024);
1843 }
1844