xref: /openbmc/linux/sound/usb/pcm.c (revision 78560d41)
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(0x07fd, 0x0008): /* MOTU M Series */
365 		ep = 0x81;
366 		ifnum = 2;
367 		goto add_sync_ep_from_ifnum;
368 	case USB_ID(0x0582, 0x01d8): /* BOSS Katana */
369 		/* BOSS Katana amplifiers do not need quirks */
370 		return 0;
371 	}
372 
373 	if (attr == USB_ENDPOINT_SYNC_ASYNC &&
374 	    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
375 	    altsd->bInterfaceProtocol == 2 &&
376 	    altsd->bNumEndpoints == 1 &&
377 	    USB_ID_VENDOR(subs->stream->chip->usb_id) == 0x0582 /* Roland */ &&
378 	    search_roland_implicit_fb(dev, altsd->bInterfaceNumber + 1,
379 				      altsd->bAlternateSetting,
380 				      &alts, &ep) >= 0) {
381 		goto add_sync_ep;
382 	}
383 
384 	/* No quirk */
385 	return 0;
386 
387 add_sync_ep_from_ifnum:
388 	iface = usb_ifnum_to_if(dev, ifnum);
389 
390 	if (!iface || iface->num_altsetting < 2)
391 		return -EINVAL;
392 
393 	alts = &iface->altsetting[1];
394 
395 add_sync_ep:
396 	subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
397 						   alts, ep, !subs->direction,
398 						   SND_USB_ENDPOINT_TYPE_DATA);
399 	if (!subs->sync_endpoint)
400 		return -EINVAL;
401 
402 	subs->data_endpoint->sync_master = subs->sync_endpoint;
403 
404 	return 1;
405 }
406 
407 static int set_sync_endpoint(struct snd_usb_substream *subs,
408 			     struct audioformat *fmt,
409 			     struct usb_device *dev,
410 			     struct usb_host_interface *alts,
411 			     struct usb_interface_descriptor *altsd)
412 {
413 	int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
414 	unsigned int ep, attr;
415 	bool implicit_fb;
416 	int err;
417 
418 	/* we need a sync pipe in async OUT or adaptive IN mode */
419 	/* check the number of EP, since some devices have broken
420 	 * descriptors which fool us.  if it has only one EP,
421 	 * assume it as adaptive-out or sync-in.
422 	 */
423 	attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
424 
425 	if ((is_playback && (attr != USB_ENDPOINT_SYNC_ASYNC)) ||
426 		(!is_playback && (attr != USB_ENDPOINT_SYNC_ADAPTIVE))) {
427 
428 		/*
429 		 * In these modes the notion of sync_endpoint is irrelevant.
430 		 * Reset pointers to avoid using stale data from previously
431 		 * used settings, e.g. when configuration and endpoints were
432 		 * changed
433 		 */
434 
435 		subs->sync_endpoint = NULL;
436 		subs->data_endpoint->sync_master = NULL;
437 	}
438 
439 	err = set_sync_ep_implicit_fb_quirk(subs, dev, altsd, attr);
440 	if (err < 0)
441 		return err;
442 
443 	/* endpoint set by quirk */
444 	if (err > 0)
445 		return 0;
446 
447 	if (altsd->bNumEndpoints < 2)
448 		return 0;
449 
450 	if ((is_playback && (attr == USB_ENDPOINT_SYNC_SYNC ||
451 			     attr == USB_ENDPOINT_SYNC_ADAPTIVE)) ||
452 	    (!is_playback && attr != USB_ENDPOINT_SYNC_ADAPTIVE))
453 		return 0;
454 
455 	/*
456 	 * In case of illegal SYNC_NONE for OUT endpoint, we keep going to see
457 	 * if we don't find a sync endpoint, as on M-Audio Transit. In case of
458 	 * error fall back to SYNC mode and don't create sync endpoint
459 	 */
460 
461 	/* check sync-pipe endpoint */
462 	/* ... and check descriptor size before accessing bSynchAddress
463 	   because there is a version of the SB Audigy 2 NX firmware lacking
464 	   the audio fields in the endpoint descriptors */
465 	if ((get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) != USB_ENDPOINT_XFER_ISOC ||
466 	    (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
467 	     get_endpoint(alts, 1)->bSynchAddress != 0)) {
468 		dev_err(&dev->dev,
469 			"%d:%d : invalid sync pipe. bmAttributes %02x, bLength %d, bSynchAddress %02x\n",
470 			   fmt->iface, fmt->altsetting,
471 			   get_endpoint(alts, 1)->bmAttributes,
472 			   get_endpoint(alts, 1)->bLength,
473 			   get_endpoint(alts, 1)->bSynchAddress);
474 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
475 			return 0;
476 		return -EINVAL;
477 	}
478 	ep = get_endpoint(alts, 1)->bEndpointAddress;
479 	if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
480 	    get_endpoint(alts, 0)->bSynchAddress != 0 &&
481 	    ((is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
482 	     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
483 		dev_err(&dev->dev,
484 			"%d:%d : invalid sync pipe. is_playback %d, ep %02x, bSynchAddress %02x\n",
485 			   fmt->iface, fmt->altsetting,
486 			   is_playback, ep, get_endpoint(alts, 0)->bSynchAddress);
487 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
488 			return 0;
489 		return -EINVAL;
490 	}
491 
492 	implicit_fb = (get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_USAGE_MASK)
493 			== USB_ENDPOINT_USAGE_IMPLICIT_FB;
494 
495 	subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
496 						   alts, ep, !subs->direction,
497 						   implicit_fb ?
498 							SND_USB_ENDPOINT_TYPE_DATA :
499 							SND_USB_ENDPOINT_TYPE_SYNC);
500 	if (!subs->sync_endpoint) {
501 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
502 			return 0;
503 		return -EINVAL;
504 	}
505 
506 	subs->data_endpoint->sync_master = subs->sync_endpoint;
507 
508 	return 0;
509 }
510 
511 /*
512  * find a matching format and set up the interface
513  */
514 static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
515 {
516 	struct usb_device *dev = subs->dev;
517 	struct usb_host_interface *alts;
518 	struct usb_interface_descriptor *altsd;
519 	struct usb_interface *iface;
520 	int err;
521 
522 	iface = usb_ifnum_to_if(dev, fmt->iface);
523 	if (WARN_ON(!iface))
524 		return -EINVAL;
525 	alts = usb_altnum_to_altsetting(iface, fmt->altsetting);
526 	if (WARN_ON(!alts))
527 		return -EINVAL;
528 	altsd = get_iface_desc(alts);
529 
530 	if (fmt == subs->cur_audiofmt && !subs->need_setup_fmt)
531 		return 0;
532 
533 	/* close the old interface */
534 	if (subs->interface >= 0 && (subs->interface != fmt->iface || subs->need_setup_fmt)) {
535 		if (!subs->stream->chip->keep_iface) {
536 			err = usb_set_interface(subs->dev, subs->interface, 0);
537 			if (err < 0) {
538 				dev_err(&dev->dev,
539 					"%d:%d: return to setting 0 failed (%d)\n",
540 					fmt->iface, fmt->altsetting, err);
541 				return -EIO;
542 			}
543 		}
544 		subs->interface = -1;
545 		subs->altset_idx = 0;
546 	}
547 
548 	if (subs->need_setup_fmt)
549 		subs->need_setup_fmt = false;
550 
551 	/* set interface */
552 	if (iface->cur_altsetting != alts) {
553 		err = snd_usb_select_mode_quirk(subs, fmt);
554 		if (err < 0)
555 			return -EIO;
556 
557 		err = usb_set_interface(dev, fmt->iface, fmt->altsetting);
558 		if (err < 0) {
559 			dev_err(&dev->dev,
560 				"%d:%d: usb_set_interface failed (%d)\n",
561 				fmt->iface, fmt->altsetting, err);
562 			return -EIO;
563 		}
564 		dev_dbg(&dev->dev, "setting usb interface %d:%d\n",
565 			fmt->iface, fmt->altsetting);
566 		snd_usb_set_interface_quirk(dev);
567 	}
568 
569 	subs->interface = fmt->iface;
570 	subs->altset_idx = fmt->altset_idx;
571 	subs->data_endpoint = snd_usb_add_endpoint(subs->stream->chip,
572 						   alts, fmt->endpoint, subs->direction,
573 						   SND_USB_ENDPOINT_TYPE_DATA);
574 
575 	if (!subs->data_endpoint)
576 		return -EINVAL;
577 
578 	err = set_sync_endpoint(subs, fmt, dev, alts, altsd);
579 	if (err < 0)
580 		return err;
581 
582 	err = snd_usb_init_pitch(subs->stream->chip, fmt->iface, alts, fmt);
583 	if (err < 0)
584 		return err;
585 
586 	subs->cur_audiofmt = fmt;
587 
588 	snd_usb_set_format_quirk(subs, fmt);
589 
590 	return 0;
591 }
592 
593 /*
594  * Return the score of matching two audioformats.
595  * Veto the audioformat if:
596  * - It has no channels for some reason.
597  * - Requested PCM format is not supported.
598  * - Requested sample rate is not supported.
599  */
600 static int match_endpoint_audioformats(struct snd_usb_substream *subs,
601 				       struct audioformat *fp,
602 				       struct audioformat *match, int rate,
603 				       snd_pcm_format_t pcm_format)
604 {
605 	int i;
606 	int score = 0;
607 
608 	if (fp->channels < 1) {
609 		dev_dbg(&subs->dev->dev,
610 			"%s: (fmt @%p) no channels\n", __func__, fp);
611 		return 0;
612 	}
613 
614 	if (!(fp->formats & pcm_format_to_bits(pcm_format))) {
615 		dev_dbg(&subs->dev->dev,
616 			"%s: (fmt @%p) no match for format %d\n", __func__,
617 			fp, pcm_format);
618 		return 0;
619 	}
620 
621 	for (i = 0; i < fp->nr_rates; i++) {
622 		if (fp->rate_table[i] == rate) {
623 			score++;
624 			break;
625 		}
626 	}
627 	if (!score) {
628 		dev_dbg(&subs->dev->dev,
629 			"%s: (fmt @%p) no match for rate %d\n", __func__,
630 			fp, rate);
631 		return 0;
632 	}
633 
634 	if (fp->channels == match->channels)
635 		score++;
636 
637 	dev_dbg(&subs->dev->dev,
638 		"%s: (fmt @%p) score %d\n", __func__, fp, score);
639 
640 	return score;
641 }
642 
643 /*
644  * Configure the sync ep using the rate and pcm format of the data ep.
645  */
646 static int configure_sync_endpoint(struct snd_usb_substream *subs)
647 {
648 	int ret;
649 	struct audioformat *fp;
650 	struct audioformat *sync_fp = NULL;
651 	int cur_score = 0;
652 	int sync_period_bytes = subs->period_bytes;
653 	struct snd_usb_substream *sync_subs =
654 		&subs->stream->substream[subs->direction ^ 1];
655 
656 	if (subs->sync_endpoint->type != SND_USB_ENDPOINT_TYPE_DATA ||
657 	    !subs->stream)
658 		return snd_usb_endpoint_set_params(subs->sync_endpoint,
659 						   subs->pcm_format,
660 						   subs->channels,
661 						   subs->period_bytes,
662 						   0, 0,
663 						   subs->cur_rate,
664 						   subs->cur_audiofmt,
665 						   NULL);
666 
667 	/* Try to find the best matching audioformat. */
668 	list_for_each_entry(fp, &sync_subs->fmt_list, list) {
669 		int score = match_endpoint_audioformats(subs,
670 							fp, subs->cur_audiofmt,
671 			subs->cur_rate, subs->pcm_format);
672 
673 		if (score > cur_score) {
674 			sync_fp = fp;
675 			cur_score = score;
676 		}
677 	}
678 
679 	if (unlikely(sync_fp == NULL)) {
680 		dev_err(&subs->dev->dev,
681 			"%s: no valid audioformat for sync ep %x found\n",
682 			__func__, sync_subs->ep_num);
683 		return -EINVAL;
684 	}
685 
686 	/*
687 	 * Recalculate the period bytes if channel number differ between
688 	 * data and sync ep audioformat.
689 	 */
690 	if (sync_fp->channels != subs->channels) {
691 		sync_period_bytes = (subs->period_bytes / subs->channels) *
692 			sync_fp->channels;
693 		dev_dbg(&subs->dev->dev,
694 			"%s: adjusted sync ep period bytes (%d -> %d)\n",
695 			__func__, subs->period_bytes, sync_period_bytes);
696 	}
697 
698 	ret = snd_usb_endpoint_set_params(subs->sync_endpoint,
699 					  subs->pcm_format,
700 					  sync_fp->channels,
701 					  sync_period_bytes,
702 					  0, 0,
703 					  subs->cur_rate,
704 					  sync_fp,
705 					  NULL);
706 
707 	return ret;
708 }
709 
710 /*
711  * configure endpoint params
712  *
713  * called  during initial setup and upon resume
714  */
715 static int configure_endpoint(struct snd_usb_substream *subs)
716 {
717 	int ret;
718 
719 	/* format changed */
720 	stop_endpoints(subs);
721 	sync_pending_stops(subs);
722 	ret = snd_usb_endpoint_set_params(subs->data_endpoint,
723 					  subs->pcm_format,
724 					  subs->channels,
725 					  subs->period_bytes,
726 					  subs->period_frames,
727 					  subs->buffer_periods,
728 					  subs->cur_rate,
729 					  subs->cur_audiofmt,
730 					  subs->sync_endpoint);
731 	if (ret < 0)
732 		return ret;
733 
734 	if (subs->sync_endpoint)
735 		ret = configure_sync_endpoint(subs);
736 
737 	return ret;
738 }
739 
740 static int snd_usb_pcm_change_state(struct snd_usb_substream *subs, int state)
741 {
742 	int ret;
743 
744 	if (!subs->str_pd)
745 		return 0;
746 
747 	ret = snd_usb_power_domain_set(subs->stream->chip, subs->str_pd, state);
748 	if (ret < 0) {
749 		dev_err(&subs->dev->dev,
750 			"Cannot change Power Domain ID: %d to state: %d. Err: %d\n",
751 			subs->str_pd->pd_id, state, ret);
752 		return ret;
753 	}
754 
755 	return 0;
756 }
757 
758 int snd_usb_pcm_suspend(struct snd_usb_stream *as)
759 {
760 	int ret;
761 
762 	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D2);
763 	if (ret < 0)
764 		return ret;
765 
766 	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D2);
767 	if (ret < 0)
768 		return ret;
769 
770 	return 0;
771 }
772 
773 int snd_usb_pcm_resume(struct snd_usb_stream *as)
774 {
775 	int ret;
776 
777 	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D1);
778 	if (ret < 0)
779 		return ret;
780 
781 	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D1);
782 	if (ret < 0)
783 		return ret;
784 
785 	return 0;
786 }
787 
788 /*
789  * hw_params callback
790  *
791  * allocate a buffer and set the given audio format.
792  *
793  * so far we use a physically linear buffer although packetize transfer
794  * doesn't need a continuous area.
795  * if sg buffer is supported on the later version of alsa, we'll follow
796  * that.
797  */
798 static int snd_usb_hw_params(struct snd_pcm_substream *substream,
799 			     struct snd_pcm_hw_params *hw_params)
800 {
801 	struct snd_usb_substream *subs = substream->runtime->private_data;
802 	struct audioformat *fmt;
803 	int ret;
804 
805 	ret = snd_media_start_pipeline(subs);
806 	if (ret)
807 		return ret;
808 
809 	subs->pcm_format = params_format(hw_params);
810 	subs->period_bytes = params_period_bytes(hw_params);
811 	subs->period_frames = params_period_size(hw_params);
812 	subs->buffer_periods = params_periods(hw_params);
813 	subs->channels = params_channels(hw_params);
814 	subs->cur_rate = params_rate(hw_params);
815 
816 	fmt = find_format(subs);
817 	if (!fmt) {
818 		dev_dbg(&subs->dev->dev,
819 			"cannot set format: format = %#x, rate = %d, channels = %d\n",
820 			   subs->pcm_format, subs->cur_rate, subs->channels);
821 		ret = -EINVAL;
822 		goto stop_pipeline;
823 	}
824 
825 	ret = snd_usb_lock_shutdown(subs->stream->chip);
826 	if (ret < 0)
827 		goto stop_pipeline;
828 
829 	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
830 	if (ret < 0)
831 		goto unlock;
832 
833 	ret = set_format(subs, fmt);
834 	if (ret < 0)
835 		goto unlock;
836 
837 	subs->interface = fmt->iface;
838 	subs->altset_idx = fmt->altset_idx;
839 	subs->need_setup_ep = true;
840 
841  unlock:
842 	snd_usb_unlock_shutdown(subs->stream->chip);
843 	if (ret < 0)
844 		goto stop_pipeline;
845 	return ret;
846 
847  stop_pipeline:
848 	snd_media_stop_pipeline(subs);
849 	return ret;
850 }
851 
852 /*
853  * hw_free callback
854  *
855  * reset the audio format and release the buffer
856  */
857 static int snd_usb_hw_free(struct snd_pcm_substream *substream)
858 {
859 	struct snd_usb_substream *subs = substream->runtime->private_data;
860 
861 	snd_media_stop_pipeline(subs);
862 	subs->cur_audiofmt = NULL;
863 	subs->cur_rate = 0;
864 	subs->period_bytes = 0;
865 	if (!snd_usb_lock_shutdown(subs->stream->chip)) {
866 		stop_endpoints(subs);
867 		sync_pending_stops(subs);
868 		snd_usb_endpoint_deactivate(subs->sync_endpoint);
869 		snd_usb_endpoint_deactivate(subs->data_endpoint);
870 		snd_usb_unlock_shutdown(subs->stream->chip);
871 	}
872 
873 	return 0;
874 }
875 
876 /*
877  * prepare callback
878  *
879  * only a few subtle things...
880  */
881 static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
882 {
883 	struct snd_pcm_runtime *runtime = substream->runtime;
884 	struct snd_usb_substream *subs = runtime->private_data;
885 	struct usb_host_interface *alts;
886 	struct usb_interface *iface;
887 	int ret;
888 
889 	if (! subs->cur_audiofmt) {
890 		dev_err(&subs->dev->dev, "no format is specified!\n");
891 		return -ENXIO;
892 	}
893 
894 	ret = snd_usb_lock_shutdown(subs->stream->chip);
895 	if (ret < 0)
896 		return ret;
897 	if (snd_BUG_ON(!subs->data_endpoint)) {
898 		ret = -EIO;
899 		goto unlock;
900 	}
901 
902 	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
903 	if (ret < 0)
904 		goto unlock;
905 
906 	ret = set_format(subs, subs->cur_audiofmt);
907 	if (ret < 0)
908 		goto unlock;
909 
910 	if (subs->need_setup_ep) {
911 
912 		iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
913 		alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
914 		ret = snd_usb_init_sample_rate(subs->stream->chip,
915 					       subs->cur_audiofmt->iface,
916 					       alts,
917 					       subs->cur_audiofmt,
918 					       subs->cur_rate);
919 		if (ret < 0)
920 			goto unlock;
921 
922 		ret = configure_endpoint(subs);
923 		if (ret < 0)
924 			goto unlock;
925 		subs->need_setup_ep = false;
926 	}
927 
928 	/* some unit conversions in runtime */
929 	subs->data_endpoint->maxframesize =
930 		bytes_to_frames(runtime, subs->data_endpoint->maxpacksize);
931 	subs->data_endpoint->curframesize =
932 		bytes_to_frames(runtime, subs->data_endpoint->curpacksize);
933 
934 	/* reset the pointer */
935 	subs->hwptr_done = 0;
936 	subs->transfer_done = 0;
937 	subs->last_delay = 0;
938 	subs->last_frame_number = 0;
939 	runtime->delay = 0;
940 
941 	/* for playback, submit the URBs now; otherwise, the first hwptr_done
942 	 * updates for all URBs would happen at the same time when starting */
943 	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK)
944 		ret = start_endpoints(subs);
945 
946  unlock:
947 	snd_usb_unlock_shutdown(subs->stream->chip);
948 	return ret;
949 }
950 
951 static const struct snd_pcm_hardware snd_usb_hardware =
952 {
953 	.info =			SNDRV_PCM_INFO_MMAP |
954 				SNDRV_PCM_INFO_MMAP_VALID |
955 				SNDRV_PCM_INFO_BATCH |
956 				SNDRV_PCM_INFO_INTERLEAVED |
957 				SNDRV_PCM_INFO_BLOCK_TRANSFER |
958 				SNDRV_PCM_INFO_PAUSE,
959 	.buffer_bytes_max =	1024 * 1024,
960 	.period_bytes_min =	64,
961 	.period_bytes_max =	512 * 1024,
962 	.periods_min =		2,
963 	.periods_max =		1024,
964 };
965 
966 static int hw_check_valid_format(struct snd_usb_substream *subs,
967 				 struct snd_pcm_hw_params *params,
968 				 struct audioformat *fp)
969 {
970 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
971 	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
972 	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
973 	struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
974 	struct snd_mask check_fmts;
975 	unsigned int ptime;
976 
977 	/* check the format */
978 	snd_mask_none(&check_fmts);
979 	check_fmts.bits[0] = (u32)fp->formats;
980 	check_fmts.bits[1] = (u32)(fp->formats >> 32);
981 	snd_mask_intersect(&check_fmts, fmts);
982 	if (snd_mask_empty(&check_fmts)) {
983 		hwc_debug("   > check: no supported format %d\n", fp->format);
984 		return 0;
985 	}
986 	/* check the channels */
987 	if (fp->channels < ct->min || fp->channels > ct->max) {
988 		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
989 		return 0;
990 	}
991 	/* check the rate is within the range */
992 	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
993 		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
994 		return 0;
995 	}
996 	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
997 		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
998 		return 0;
999 	}
1000 	/* check whether the period time is >= the data packet interval */
1001 	if (subs->speed != USB_SPEED_FULL) {
1002 		ptime = 125 * (1 << fp->datainterval);
1003 		if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
1004 			hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
1005 			return 0;
1006 		}
1007 	}
1008 	return 1;
1009 }
1010 
1011 static int hw_rule_rate(struct snd_pcm_hw_params *params,
1012 			struct snd_pcm_hw_rule *rule)
1013 {
1014 	struct snd_usb_substream *subs = rule->private;
1015 	struct audioformat *fp;
1016 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
1017 	unsigned int rmin, rmax;
1018 	int changed;
1019 
1020 	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
1021 	changed = 0;
1022 	rmin = rmax = 0;
1023 	list_for_each_entry(fp, &subs->fmt_list, list) {
1024 		if (!hw_check_valid_format(subs, params, fp))
1025 			continue;
1026 		if (changed++) {
1027 			if (rmin > fp->rate_min)
1028 				rmin = fp->rate_min;
1029 			if (rmax < fp->rate_max)
1030 				rmax = fp->rate_max;
1031 		} else {
1032 			rmin = fp->rate_min;
1033 			rmax = fp->rate_max;
1034 		}
1035 	}
1036 
1037 	if (!changed) {
1038 		hwc_debug("  --> get empty\n");
1039 		it->empty = 1;
1040 		return -EINVAL;
1041 	}
1042 
1043 	changed = 0;
1044 	if (it->min < rmin) {
1045 		it->min = rmin;
1046 		it->openmin = 0;
1047 		changed = 1;
1048 	}
1049 	if (it->max > rmax) {
1050 		it->max = rmax;
1051 		it->openmax = 0;
1052 		changed = 1;
1053 	}
1054 	if (snd_interval_checkempty(it)) {
1055 		it->empty = 1;
1056 		return -EINVAL;
1057 	}
1058 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
1059 	return changed;
1060 }
1061 
1062 
1063 static int hw_rule_channels(struct snd_pcm_hw_params *params,
1064 			    struct snd_pcm_hw_rule *rule)
1065 {
1066 	struct snd_usb_substream *subs = rule->private;
1067 	struct audioformat *fp;
1068 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
1069 	unsigned int rmin, rmax;
1070 	int changed;
1071 
1072 	hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
1073 	changed = 0;
1074 	rmin = rmax = 0;
1075 	list_for_each_entry(fp, &subs->fmt_list, list) {
1076 		if (!hw_check_valid_format(subs, params, fp))
1077 			continue;
1078 		if (changed++) {
1079 			if (rmin > fp->channels)
1080 				rmin = fp->channels;
1081 			if (rmax < fp->channels)
1082 				rmax = fp->channels;
1083 		} else {
1084 			rmin = fp->channels;
1085 			rmax = fp->channels;
1086 		}
1087 	}
1088 
1089 	if (!changed) {
1090 		hwc_debug("  --> get empty\n");
1091 		it->empty = 1;
1092 		return -EINVAL;
1093 	}
1094 
1095 	changed = 0;
1096 	if (it->min < rmin) {
1097 		it->min = rmin;
1098 		it->openmin = 0;
1099 		changed = 1;
1100 	}
1101 	if (it->max > rmax) {
1102 		it->max = rmax;
1103 		it->openmax = 0;
1104 		changed = 1;
1105 	}
1106 	if (snd_interval_checkempty(it)) {
1107 		it->empty = 1;
1108 		return -EINVAL;
1109 	}
1110 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
1111 	return changed;
1112 }
1113 
1114 static int hw_rule_format(struct snd_pcm_hw_params *params,
1115 			  struct snd_pcm_hw_rule *rule)
1116 {
1117 	struct snd_usb_substream *subs = rule->private;
1118 	struct audioformat *fp;
1119 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
1120 	u64 fbits;
1121 	u32 oldbits[2];
1122 	int changed;
1123 
1124 	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
1125 	fbits = 0;
1126 	list_for_each_entry(fp, &subs->fmt_list, list) {
1127 		if (!hw_check_valid_format(subs, params, fp))
1128 			continue;
1129 		fbits |= fp->formats;
1130 	}
1131 
1132 	oldbits[0] = fmt->bits[0];
1133 	oldbits[1] = fmt->bits[1];
1134 	fmt->bits[0] &= (u32)fbits;
1135 	fmt->bits[1] &= (u32)(fbits >> 32);
1136 	if (!fmt->bits[0] && !fmt->bits[1]) {
1137 		hwc_debug("  --> get empty\n");
1138 		return -EINVAL;
1139 	}
1140 	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
1141 	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
1142 	return changed;
1143 }
1144 
1145 static int hw_rule_period_time(struct snd_pcm_hw_params *params,
1146 			       struct snd_pcm_hw_rule *rule)
1147 {
1148 	struct snd_usb_substream *subs = rule->private;
1149 	struct audioformat *fp;
1150 	struct snd_interval *it;
1151 	unsigned char min_datainterval;
1152 	unsigned int pmin;
1153 	int changed;
1154 
1155 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
1156 	hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
1157 	min_datainterval = 0xff;
1158 	list_for_each_entry(fp, &subs->fmt_list, list) {
1159 		if (!hw_check_valid_format(subs, params, fp))
1160 			continue;
1161 		min_datainterval = min(min_datainterval, fp->datainterval);
1162 	}
1163 	if (min_datainterval == 0xff) {
1164 		hwc_debug("  --> get empty\n");
1165 		it->empty = 1;
1166 		return -EINVAL;
1167 	}
1168 	pmin = 125 * (1 << min_datainterval);
1169 	changed = 0;
1170 	if (it->min < pmin) {
1171 		it->min = pmin;
1172 		it->openmin = 0;
1173 		changed = 1;
1174 	}
1175 	if (snd_interval_checkempty(it)) {
1176 		it->empty = 1;
1177 		return -EINVAL;
1178 	}
1179 	hwc_debug("  --> (%u,%u) (changed = %d)\n", it->min, it->max, changed);
1180 	return changed;
1181 }
1182 
1183 /*
1184  *  If the device supports unusual bit rates, does the request meet these?
1185  */
1186 static int snd_usb_pcm_check_knot(struct snd_pcm_runtime *runtime,
1187 				  struct snd_usb_substream *subs)
1188 {
1189 	struct audioformat *fp;
1190 	int *rate_list;
1191 	int count = 0, needs_knot = 0;
1192 	int err;
1193 
1194 	kfree(subs->rate_list.list);
1195 	subs->rate_list.list = NULL;
1196 
1197 	list_for_each_entry(fp, &subs->fmt_list, list) {
1198 		if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)
1199 			return 0;
1200 		count += fp->nr_rates;
1201 		if (fp->rates & SNDRV_PCM_RATE_KNOT)
1202 			needs_knot = 1;
1203 	}
1204 	if (!needs_knot)
1205 		return 0;
1206 
1207 	subs->rate_list.list = rate_list =
1208 		kmalloc_array(count, sizeof(int), GFP_KERNEL);
1209 	if (!subs->rate_list.list)
1210 		return -ENOMEM;
1211 	subs->rate_list.count = count;
1212 	subs->rate_list.mask = 0;
1213 	count = 0;
1214 	list_for_each_entry(fp, &subs->fmt_list, list) {
1215 		int i;
1216 		for (i = 0; i < fp->nr_rates; i++)
1217 			rate_list[count++] = fp->rate_table[i];
1218 	}
1219 	err = snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1220 					 &subs->rate_list);
1221 	if (err < 0)
1222 		return err;
1223 
1224 	return 0;
1225 }
1226 
1227 
1228 /*
1229  * set up the runtime hardware information.
1230  */
1231 
1232 static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
1233 {
1234 	struct audioformat *fp;
1235 	unsigned int pt, ptmin;
1236 	int param_period_time_if_needed;
1237 	int err;
1238 
1239 	runtime->hw.formats = subs->formats;
1240 
1241 	runtime->hw.rate_min = 0x7fffffff;
1242 	runtime->hw.rate_max = 0;
1243 	runtime->hw.channels_min = 256;
1244 	runtime->hw.channels_max = 0;
1245 	runtime->hw.rates = 0;
1246 	ptmin = UINT_MAX;
1247 	/* check min/max rates and channels */
1248 	list_for_each_entry(fp, &subs->fmt_list, list) {
1249 		runtime->hw.rates |= fp->rates;
1250 		if (runtime->hw.rate_min > fp->rate_min)
1251 			runtime->hw.rate_min = fp->rate_min;
1252 		if (runtime->hw.rate_max < fp->rate_max)
1253 			runtime->hw.rate_max = fp->rate_max;
1254 		if (runtime->hw.channels_min > fp->channels)
1255 			runtime->hw.channels_min = fp->channels;
1256 		if (runtime->hw.channels_max < fp->channels)
1257 			runtime->hw.channels_max = fp->channels;
1258 		if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
1259 			/* FIXME: there might be more than one audio formats... */
1260 			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
1261 				fp->frame_size;
1262 		}
1263 		pt = 125 * (1 << fp->datainterval);
1264 		ptmin = min(ptmin, pt);
1265 	}
1266 
1267 	param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
1268 	if (subs->speed == USB_SPEED_FULL)
1269 		/* full speed devices have fixed data packet interval */
1270 		ptmin = 1000;
1271 	if (ptmin == 1000)
1272 		/* if period time doesn't go below 1 ms, no rules needed */
1273 		param_period_time_if_needed = -1;
1274 
1275 	err = snd_pcm_hw_constraint_minmax(runtime,
1276 					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1277 					   ptmin, UINT_MAX);
1278 	if (err < 0)
1279 		return err;
1280 
1281 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1282 				  hw_rule_rate, subs,
1283 				  SNDRV_PCM_HW_PARAM_FORMAT,
1284 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1285 				  param_period_time_if_needed,
1286 				  -1);
1287 	if (err < 0)
1288 		return err;
1289 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
1290 				  hw_rule_channels, subs,
1291 				  SNDRV_PCM_HW_PARAM_FORMAT,
1292 				  SNDRV_PCM_HW_PARAM_RATE,
1293 				  param_period_time_if_needed,
1294 				  -1);
1295 	if (err < 0)
1296 		return err;
1297 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1298 				  hw_rule_format, subs,
1299 				  SNDRV_PCM_HW_PARAM_RATE,
1300 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1301 				  param_period_time_if_needed,
1302 				  -1);
1303 	if (err < 0)
1304 		return err;
1305 	if (param_period_time_if_needed >= 0) {
1306 		err = snd_pcm_hw_rule_add(runtime, 0,
1307 					  SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1308 					  hw_rule_period_time, subs,
1309 					  SNDRV_PCM_HW_PARAM_FORMAT,
1310 					  SNDRV_PCM_HW_PARAM_CHANNELS,
1311 					  SNDRV_PCM_HW_PARAM_RATE,
1312 					  -1);
1313 		if (err < 0)
1314 			return err;
1315 	}
1316 	err = snd_usb_pcm_check_knot(runtime, subs);
1317 	if (err < 0)
1318 		return err;
1319 
1320 	return snd_usb_autoresume(subs->stream->chip);
1321 }
1322 
1323 static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
1324 {
1325 	int direction = substream->stream;
1326 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1327 	struct snd_pcm_runtime *runtime = substream->runtime;
1328 	struct snd_usb_substream *subs = &as->substream[direction];
1329 	int ret;
1330 
1331 	subs->interface = -1;
1332 	subs->altset_idx = 0;
1333 	runtime->hw = snd_usb_hardware;
1334 	runtime->private_data = subs;
1335 	subs->pcm_substream = substream;
1336 	/* runtime PM is also done there */
1337 
1338 	/* initialize DSD/DOP context */
1339 	subs->dsd_dop.byte_idx = 0;
1340 	subs->dsd_dop.channel = 0;
1341 	subs->dsd_dop.marker = 1;
1342 
1343 	ret = setup_hw_info(runtime, subs);
1344 	if (ret == 0) {
1345 		ret = snd_media_stream_init(subs, as->pcm, direction);
1346 		if (ret)
1347 			snd_usb_autosuspend(subs->stream->chip);
1348 	}
1349 	return ret;
1350 }
1351 
1352 static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
1353 {
1354 	int direction = substream->stream;
1355 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1356 	struct snd_usb_substream *subs = &as->substream[direction];
1357 	int ret;
1358 
1359 	snd_media_stop_pipeline(subs);
1360 
1361 	if (!as->chip->keep_iface &&
1362 	    subs->interface >= 0 &&
1363 	    !snd_usb_lock_shutdown(subs->stream->chip)) {
1364 		usb_set_interface(subs->dev, subs->interface, 0);
1365 		subs->interface = -1;
1366 		ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
1367 		snd_usb_unlock_shutdown(subs->stream->chip);
1368 		if (ret < 0)
1369 			return ret;
1370 	}
1371 
1372 	subs->pcm_substream = NULL;
1373 	snd_usb_autosuspend(subs->stream->chip);
1374 
1375 	return 0;
1376 }
1377 
1378 /* Since a URB can handle only a single linear buffer, we must use double
1379  * buffering when the data to be transferred overflows the buffer boundary.
1380  * To avoid inconsistencies when updating hwptr_done, we use double buffering
1381  * for all URBs.
1382  */
1383 static void retire_capture_urb(struct snd_usb_substream *subs,
1384 			       struct urb *urb)
1385 {
1386 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1387 	unsigned int stride, frames, bytes, oldptr;
1388 	int i, period_elapsed = 0;
1389 	unsigned long flags;
1390 	unsigned char *cp;
1391 	int current_frame_number;
1392 
1393 	/* read frame number here, update pointer in critical section */
1394 	current_frame_number = usb_get_current_frame_number(subs->dev);
1395 
1396 	stride = runtime->frame_bits >> 3;
1397 
1398 	for (i = 0; i < urb->number_of_packets; i++) {
1399 		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;
1400 		if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
1401 			dev_dbg(&subs->dev->dev, "frame %d active: %d\n",
1402 				i, urb->iso_frame_desc[i].status);
1403 			// continue;
1404 		}
1405 		bytes = urb->iso_frame_desc[i].actual_length;
1406 		frames = bytes / stride;
1407 		if (!subs->txfr_quirk)
1408 			bytes = frames * stride;
1409 		if (bytes % (runtime->sample_bits >> 3) != 0) {
1410 			int oldbytes = bytes;
1411 			bytes = frames * stride;
1412 			dev_warn_ratelimited(&subs->dev->dev,
1413 				 "Corrected urb data len. %d->%d\n",
1414 							oldbytes, bytes);
1415 		}
1416 		/* update the current pointer */
1417 		spin_lock_irqsave(&subs->lock, flags);
1418 		oldptr = subs->hwptr_done;
1419 		subs->hwptr_done += bytes;
1420 		if (subs->hwptr_done >= runtime->buffer_size * stride)
1421 			subs->hwptr_done -= runtime->buffer_size * stride;
1422 		frames = (bytes + (oldptr % stride)) / stride;
1423 		subs->transfer_done += frames;
1424 		if (subs->transfer_done >= runtime->period_size) {
1425 			subs->transfer_done -= runtime->period_size;
1426 			period_elapsed = 1;
1427 		}
1428 		/* capture delay is by construction limited to one URB,
1429 		 * reset delays here
1430 		 */
1431 		runtime->delay = subs->last_delay = 0;
1432 
1433 		/* realign last_frame_number */
1434 		subs->last_frame_number = current_frame_number;
1435 		subs->last_frame_number &= 0xFF; /* keep 8 LSBs */
1436 
1437 		spin_unlock_irqrestore(&subs->lock, flags);
1438 		/* copy a data chunk */
1439 		if (oldptr + bytes > runtime->buffer_size * stride) {
1440 			unsigned int bytes1 =
1441 					runtime->buffer_size * stride - oldptr;
1442 			memcpy(runtime->dma_area + oldptr, cp, bytes1);
1443 			memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
1444 		} else {
1445 			memcpy(runtime->dma_area + oldptr, cp, bytes);
1446 		}
1447 	}
1448 
1449 	if (period_elapsed)
1450 		snd_pcm_period_elapsed(subs->pcm_substream);
1451 }
1452 
1453 static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
1454 					     struct urb *urb, unsigned int bytes)
1455 {
1456 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1457 	unsigned int stride = runtime->frame_bits >> 3;
1458 	unsigned int dst_idx = 0;
1459 	unsigned int src_idx = subs->hwptr_done;
1460 	unsigned int wrap = runtime->buffer_size * stride;
1461 	u8 *dst = urb->transfer_buffer;
1462 	u8 *src = runtime->dma_area;
1463 	u8 marker[] = { 0x05, 0xfa };
1464 
1465 	/*
1466 	 * The DSP DOP format defines a way to transport DSD samples over
1467 	 * normal PCM data endpoints. It requires stuffing of marker bytes
1468 	 * (0x05 and 0xfa, alternating per sample frame), and then expects
1469 	 * 2 additional bytes of actual payload. The whole frame is stored
1470 	 * LSB.
1471 	 *
1472 	 * Hence, for a stereo transport, the buffer layout looks like this,
1473 	 * where L refers to left channel samples and R to right.
1474 	 *
1475 	 *   L1 L2 0x05   R1 R2 0x05   L3 L4 0xfa  R3 R4 0xfa
1476 	 *   L5 L6 0x05   R5 R6 0x05   L7 L8 0xfa  R7 R8 0xfa
1477 	 *   .....
1478 	 *
1479 	 */
1480 
1481 	while (bytes--) {
1482 		if (++subs->dsd_dop.byte_idx == 3) {
1483 			/* frame boundary? */
1484 			dst[dst_idx++] = marker[subs->dsd_dop.marker];
1485 			src_idx += 2;
1486 			subs->dsd_dop.byte_idx = 0;
1487 
1488 			if (++subs->dsd_dop.channel % runtime->channels == 0) {
1489 				/* alternate the marker */
1490 				subs->dsd_dop.marker++;
1491 				subs->dsd_dop.marker %= ARRAY_SIZE(marker);
1492 				subs->dsd_dop.channel = 0;
1493 			}
1494 		} else {
1495 			/* stuff the DSD payload */
1496 			int idx = (src_idx + subs->dsd_dop.byte_idx - 1) % wrap;
1497 
1498 			if (subs->cur_audiofmt->dsd_bitrev)
1499 				dst[dst_idx++] = bitrev8(src[idx]);
1500 			else
1501 				dst[dst_idx++] = src[idx];
1502 
1503 			subs->hwptr_done++;
1504 		}
1505 	}
1506 	if (subs->hwptr_done >= runtime->buffer_size * stride)
1507 		subs->hwptr_done -= runtime->buffer_size * stride;
1508 }
1509 
1510 static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
1511 			int offset, int stride, unsigned int bytes)
1512 {
1513 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1514 
1515 	if (subs->hwptr_done + bytes > runtime->buffer_size * stride) {
1516 		/* err, the transferred area goes over buffer boundary. */
1517 		unsigned int bytes1 =
1518 			runtime->buffer_size * stride - subs->hwptr_done;
1519 		memcpy(urb->transfer_buffer + offset,
1520 		       runtime->dma_area + subs->hwptr_done, bytes1);
1521 		memcpy(urb->transfer_buffer + offset + bytes1,
1522 		       runtime->dma_area, bytes - bytes1);
1523 	} else {
1524 		memcpy(urb->transfer_buffer + offset,
1525 		       runtime->dma_area + subs->hwptr_done, bytes);
1526 	}
1527 	subs->hwptr_done += bytes;
1528 	if (subs->hwptr_done >= runtime->buffer_size * stride)
1529 		subs->hwptr_done -= runtime->buffer_size * stride;
1530 }
1531 
1532 static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
1533 				      struct urb *urb, int stride,
1534 				      unsigned int bytes)
1535 {
1536 	__le32 packet_length;
1537 	int i;
1538 
1539 	/* Put __le32 length descriptor at start of each packet. */
1540 	for (i = 0; i < urb->number_of_packets; i++) {
1541 		unsigned int length = urb->iso_frame_desc[i].length;
1542 		unsigned int offset = urb->iso_frame_desc[i].offset;
1543 
1544 		packet_length = cpu_to_le32(length);
1545 		offset += i * sizeof(packet_length);
1546 		urb->iso_frame_desc[i].offset = offset;
1547 		urb->iso_frame_desc[i].length += sizeof(packet_length);
1548 		memcpy(urb->transfer_buffer + offset,
1549 		       &packet_length, sizeof(packet_length));
1550 		copy_to_urb(subs, urb, offset + sizeof(packet_length),
1551 			    stride, length);
1552 	}
1553 	/* Adjust transfer size accordingly. */
1554 	bytes += urb->number_of_packets * sizeof(packet_length);
1555 	return bytes;
1556 }
1557 
1558 static void prepare_playback_urb(struct snd_usb_substream *subs,
1559 				 struct urb *urb)
1560 {
1561 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1562 	struct snd_usb_endpoint *ep = subs->data_endpoint;
1563 	struct snd_urb_ctx *ctx = urb->context;
1564 	unsigned int counts, frames, bytes;
1565 	int i, stride, period_elapsed = 0;
1566 	unsigned long flags;
1567 
1568 	stride = runtime->frame_bits >> 3;
1569 
1570 	frames = 0;
1571 	urb->number_of_packets = 0;
1572 	spin_lock_irqsave(&subs->lock, flags);
1573 	subs->frame_limit += ep->max_urb_frames;
1574 	for (i = 0; i < ctx->packets; i++) {
1575 		if (ctx->packet_size[i])
1576 			counts = ctx->packet_size[i];
1577 		else
1578 			counts = snd_usb_endpoint_next_packet_size(ep);
1579 
1580 		/* set up descriptor */
1581 		urb->iso_frame_desc[i].offset = frames * ep->stride;
1582 		urb->iso_frame_desc[i].length = counts * ep->stride;
1583 		frames += counts;
1584 		urb->number_of_packets++;
1585 		subs->transfer_done += counts;
1586 		if (subs->transfer_done >= runtime->period_size) {
1587 			subs->transfer_done -= runtime->period_size;
1588 			subs->frame_limit = 0;
1589 			period_elapsed = 1;
1590 			if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
1591 				if (subs->transfer_done > 0) {
1592 					/* FIXME: fill-max mode is not
1593 					 * supported yet */
1594 					frames -= subs->transfer_done;
1595 					counts -= subs->transfer_done;
1596 					urb->iso_frame_desc[i].length =
1597 						counts * ep->stride;
1598 					subs->transfer_done = 0;
1599 				}
1600 				i++;
1601 				if (i < ctx->packets) {
1602 					/* add a transfer delimiter */
1603 					urb->iso_frame_desc[i].offset =
1604 						frames * ep->stride;
1605 					urb->iso_frame_desc[i].length = 0;
1606 					urb->number_of_packets++;
1607 				}
1608 				break;
1609 			}
1610 		}
1611 		/* finish at the period boundary or after enough frames */
1612 		if ((period_elapsed ||
1613 				subs->transfer_done >= subs->frame_limit) &&
1614 		    !snd_usb_endpoint_implicit_feedback_sink(ep))
1615 			break;
1616 	}
1617 	bytes = frames * ep->stride;
1618 
1619 	if (unlikely(subs->pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
1620 		     subs->cur_audiofmt->dsd_dop)) {
1621 		fill_playback_urb_dsd_dop(subs, urb, bytes);
1622 	} else if (unlikely(subs->pcm_format == SNDRV_PCM_FORMAT_DSD_U8 &&
1623 			   subs->cur_audiofmt->dsd_bitrev)) {
1624 		/* bit-reverse the bytes */
1625 		u8 *buf = urb->transfer_buffer;
1626 		for (i = 0; i < bytes; i++) {
1627 			int idx = (subs->hwptr_done + i)
1628 				% (runtime->buffer_size * stride);
1629 			buf[i] = bitrev8(runtime->dma_area[idx]);
1630 		}
1631 
1632 		subs->hwptr_done += bytes;
1633 		if (subs->hwptr_done >= runtime->buffer_size * stride)
1634 			subs->hwptr_done -= runtime->buffer_size * stride;
1635 	} else {
1636 		/* usual PCM */
1637 		if (!subs->tx_length_quirk)
1638 			copy_to_urb(subs, urb, 0, stride, bytes);
1639 		else
1640 			bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
1641 			/* bytes is now amount of outgoing data */
1642 	}
1643 
1644 	/* update delay with exact number of samples queued */
1645 	runtime->delay = subs->last_delay;
1646 	runtime->delay += frames;
1647 	subs->last_delay = runtime->delay;
1648 
1649 	/* realign last_frame_number */
1650 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1651 	subs->last_frame_number &= 0xFF; /* keep 8 LSBs */
1652 
1653 	if (subs->trigger_tstamp_pending_update) {
1654 		/* this is the first actual URB submitted,
1655 		 * update trigger timestamp to reflect actual start time
1656 		 */
1657 		snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
1658 		subs->trigger_tstamp_pending_update = false;
1659 	}
1660 
1661 	spin_unlock_irqrestore(&subs->lock, flags);
1662 	urb->transfer_buffer_length = bytes;
1663 	if (period_elapsed)
1664 		snd_pcm_period_elapsed(subs->pcm_substream);
1665 }
1666 
1667 /*
1668  * process after playback data complete
1669  * - decrease the delay count again
1670  */
1671 static void retire_playback_urb(struct snd_usb_substream *subs,
1672 			       struct urb *urb)
1673 {
1674 	unsigned long flags;
1675 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1676 	struct snd_usb_endpoint *ep = subs->data_endpoint;
1677 	int processed = urb->transfer_buffer_length / ep->stride;
1678 	int est_delay;
1679 
1680 	/* ignore the delay accounting when procssed=0 is given, i.e.
1681 	 * silent payloads are procssed before handling the actual data
1682 	 */
1683 	if (!processed)
1684 		return;
1685 
1686 	spin_lock_irqsave(&subs->lock, flags);
1687 	if (!subs->last_delay)
1688 		goto out; /* short path */
1689 
1690 	est_delay = snd_usb_pcm_delay(subs, runtime->rate);
1691 	/* update delay with exact number of samples played */
1692 	if (processed > subs->last_delay)
1693 		subs->last_delay = 0;
1694 	else
1695 		subs->last_delay -= processed;
1696 	runtime->delay = subs->last_delay;
1697 
1698 	/*
1699 	 * Report when delay estimate is off by more than 2ms.
1700 	 * The error should be lower than 2ms since the estimate relies
1701 	 * on two reads of a counter updated every ms.
1702 	 */
1703 	if (abs(est_delay - subs->last_delay) * 1000 > runtime->rate * 2)
1704 		dev_dbg_ratelimited(&subs->dev->dev,
1705 			"delay: estimated %d, actual %d\n",
1706 			est_delay, subs->last_delay);
1707 
1708 	if (!subs->running) {
1709 		/* update last_frame_number for delay counting here since
1710 		 * prepare_playback_urb won't be called during pause
1711 		 */
1712 		subs->last_frame_number =
1713 			usb_get_current_frame_number(subs->dev) & 0xff;
1714 	}
1715 
1716  out:
1717 	spin_unlock_irqrestore(&subs->lock, flags);
1718 }
1719 
1720 static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
1721 					      int cmd)
1722 {
1723 	struct snd_usb_substream *subs = substream->runtime->private_data;
1724 
1725 	switch (cmd) {
1726 	case SNDRV_PCM_TRIGGER_START:
1727 		subs->trigger_tstamp_pending_update = true;
1728 		/* fall through */
1729 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1730 		subs->data_endpoint->prepare_data_urb = prepare_playback_urb;
1731 		subs->data_endpoint->retire_data_urb = retire_playback_urb;
1732 		subs->running = 1;
1733 		return 0;
1734 	case SNDRV_PCM_TRIGGER_STOP:
1735 		stop_endpoints(subs);
1736 		subs->running = 0;
1737 		return 0;
1738 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1739 		subs->data_endpoint->prepare_data_urb = NULL;
1740 		/* keep retire_data_urb for delay calculation */
1741 		subs->data_endpoint->retire_data_urb = retire_playback_urb;
1742 		subs->running = 0;
1743 		return 0;
1744 	case SNDRV_PCM_TRIGGER_SUSPEND:
1745 		if (subs->stream->chip->setup_fmt_after_resume_quirk) {
1746 			stop_endpoints(subs);
1747 			subs->need_setup_fmt = true;
1748 			return 0;
1749 		}
1750 		break;
1751 	}
1752 
1753 	return -EINVAL;
1754 }
1755 
1756 static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
1757 					     int cmd)
1758 {
1759 	int err;
1760 	struct snd_usb_substream *subs = substream->runtime->private_data;
1761 
1762 	switch (cmd) {
1763 	case SNDRV_PCM_TRIGGER_START:
1764 		err = start_endpoints(subs);
1765 		if (err < 0)
1766 			return err;
1767 
1768 		subs->data_endpoint->retire_data_urb = retire_capture_urb;
1769 		subs->running = 1;
1770 		return 0;
1771 	case SNDRV_PCM_TRIGGER_STOP:
1772 		stop_endpoints(subs);
1773 		subs->running = 0;
1774 		return 0;
1775 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1776 		subs->data_endpoint->retire_data_urb = NULL;
1777 		subs->running = 0;
1778 		return 0;
1779 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1780 		subs->data_endpoint->retire_data_urb = retire_capture_urb;
1781 		subs->running = 1;
1782 		return 0;
1783 	case SNDRV_PCM_TRIGGER_SUSPEND:
1784 		if (subs->stream->chip->setup_fmt_after_resume_quirk) {
1785 			stop_endpoints(subs);
1786 			subs->need_setup_fmt = true;
1787 			return 0;
1788 		}
1789 		break;
1790 	}
1791 
1792 	return -EINVAL;
1793 }
1794 
1795 static const struct snd_pcm_ops snd_usb_playback_ops = {
1796 	.open =		snd_usb_pcm_open,
1797 	.close =	snd_usb_pcm_close,
1798 	.hw_params =	snd_usb_hw_params,
1799 	.hw_free =	snd_usb_hw_free,
1800 	.prepare =	snd_usb_pcm_prepare,
1801 	.trigger =	snd_usb_substream_playback_trigger,
1802 	.sync_stop =	snd_usb_pcm_sync_stop,
1803 	.pointer =	snd_usb_pcm_pointer,
1804 };
1805 
1806 static const struct snd_pcm_ops snd_usb_capture_ops = {
1807 	.open =		snd_usb_pcm_open,
1808 	.close =	snd_usb_pcm_close,
1809 	.hw_params =	snd_usb_hw_params,
1810 	.hw_free =	snd_usb_hw_free,
1811 	.prepare =	snd_usb_pcm_prepare,
1812 	.trigger =	snd_usb_substream_capture_trigger,
1813 	.sync_stop =	snd_usb_pcm_sync_stop,
1814 	.pointer =	snd_usb_pcm_pointer,
1815 };
1816 
1817 void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
1818 {
1819 	const struct snd_pcm_ops *ops;
1820 
1821 	ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
1822 			&snd_usb_playback_ops : &snd_usb_capture_ops;
1823 	snd_pcm_set_ops(pcm, stream, ops);
1824 }
1825 
1826 void snd_usb_preallocate_buffer(struct snd_usb_substream *subs)
1827 {
1828 	struct snd_pcm *pcm = subs->stream->pcm;
1829 	struct snd_pcm_substream *s = pcm->streams[subs->direction].substream;
1830 	struct device *dev = subs->dev->bus->controller;
1831 
1832 	if (snd_usb_use_vmalloc)
1833 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_VMALLOC,
1834 					   NULL, 0, 0);
1835 	else
1836 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_DEV_SG,
1837 					   dev, 64*1024, 512*1024);
1838 }
1839