xref: /openbmc/linux/sound/usb/pcm.c (revision 800e26b8)
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 	case USB_ID(0x31e9, 0x0002): /* Solid State Logic SSL2+ */
371 		ep = 0x81;
372 		ifnum = 2;
373 		goto add_sync_ep_from_ifnum;
374 	case USB_ID(0x2b73, 0x000a): /* Pioneer DJ DJM-900NXS2 */
375 		ep = 0x82;
376 		ifnum = 0;
377 		goto add_sync_ep_from_ifnum;
378 	case USB_ID(0x0582, 0x01d8): /* BOSS Katana */
379 		/* BOSS Katana amplifiers do not need quirks */
380 		return 0;
381 	}
382 
383 	if (attr == USB_ENDPOINT_SYNC_ASYNC &&
384 	    altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC &&
385 	    altsd->bInterfaceProtocol == 2 &&
386 	    altsd->bNumEndpoints == 1 &&
387 	    USB_ID_VENDOR(subs->stream->chip->usb_id) == 0x0582 /* Roland */ &&
388 	    search_roland_implicit_fb(dev, altsd->bInterfaceNumber + 1,
389 				      altsd->bAlternateSetting,
390 				      &alts, &ep) >= 0) {
391 		goto add_sync_ep;
392 	}
393 
394 	/* No quirk */
395 	return 0;
396 
397 add_sync_ep_from_ifnum:
398 	iface = usb_ifnum_to_if(dev, ifnum);
399 
400 	if (!iface || iface->num_altsetting < 2)
401 		return -EINVAL;
402 
403 	alts = &iface->altsetting[1];
404 
405 add_sync_ep:
406 	subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
407 						   alts, ep, !subs->direction,
408 						   SND_USB_ENDPOINT_TYPE_DATA);
409 	if (!subs->sync_endpoint)
410 		return -EINVAL;
411 
412 	subs->sync_endpoint->is_implicit_feedback = 1;
413 
414 	subs->data_endpoint->sync_master = subs->sync_endpoint;
415 
416 	return 1;
417 }
418 
419 static int set_sync_endpoint(struct snd_usb_substream *subs,
420 			     struct audioformat *fmt,
421 			     struct usb_device *dev,
422 			     struct usb_host_interface *alts,
423 			     struct usb_interface_descriptor *altsd)
424 {
425 	int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
426 	unsigned int ep, attr;
427 	bool implicit_fb;
428 	int err;
429 
430 	/* we need a sync pipe in async OUT or adaptive IN mode */
431 	/* check the number of EP, since some devices have broken
432 	 * descriptors which fool us.  if it has only one EP,
433 	 * assume it as adaptive-out or sync-in.
434 	 */
435 	attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
436 
437 	if ((is_playback && (attr != USB_ENDPOINT_SYNC_ASYNC)) ||
438 		(!is_playback && (attr != USB_ENDPOINT_SYNC_ADAPTIVE))) {
439 
440 		/*
441 		 * In these modes the notion of sync_endpoint is irrelevant.
442 		 * Reset pointers to avoid using stale data from previously
443 		 * used settings, e.g. when configuration and endpoints were
444 		 * changed
445 		 */
446 
447 		subs->sync_endpoint = NULL;
448 		subs->data_endpoint->sync_master = NULL;
449 	}
450 
451 	err = set_sync_ep_implicit_fb_quirk(subs, dev, altsd, attr);
452 	if (err < 0)
453 		return err;
454 
455 	/* endpoint set by quirk */
456 	if (err > 0)
457 		return 0;
458 
459 	if (altsd->bNumEndpoints < 2)
460 		return 0;
461 
462 	if ((is_playback && (attr == USB_ENDPOINT_SYNC_SYNC ||
463 			     attr == USB_ENDPOINT_SYNC_ADAPTIVE)) ||
464 	    (!is_playback && attr != USB_ENDPOINT_SYNC_ADAPTIVE))
465 		return 0;
466 
467 	/*
468 	 * In case of illegal SYNC_NONE for OUT endpoint, we keep going to see
469 	 * if we don't find a sync endpoint, as on M-Audio Transit. In case of
470 	 * error fall back to SYNC mode and don't create sync endpoint
471 	 */
472 
473 	/* check sync-pipe endpoint */
474 	/* ... and check descriptor size before accessing bSynchAddress
475 	   because there is a version of the SB Audigy 2 NX firmware lacking
476 	   the audio fields in the endpoint descriptors */
477 	if ((get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) != USB_ENDPOINT_XFER_ISOC ||
478 	    (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
479 	     get_endpoint(alts, 1)->bSynchAddress != 0)) {
480 		dev_err(&dev->dev,
481 			"%d:%d : invalid sync pipe. bmAttributes %02x, bLength %d, bSynchAddress %02x\n",
482 			   fmt->iface, fmt->altsetting,
483 			   get_endpoint(alts, 1)->bmAttributes,
484 			   get_endpoint(alts, 1)->bLength,
485 			   get_endpoint(alts, 1)->bSynchAddress);
486 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
487 			return 0;
488 		return -EINVAL;
489 	}
490 	ep = get_endpoint(alts, 1)->bEndpointAddress;
491 	if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
492 	    get_endpoint(alts, 0)->bSynchAddress != 0 &&
493 	    ((is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
494 	     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
495 		dev_err(&dev->dev,
496 			"%d:%d : invalid sync pipe. is_playback %d, ep %02x, bSynchAddress %02x\n",
497 			   fmt->iface, fmt->altsetting,
498 			   is_playback, ep, get_endpoint(alts, 0)->bSynchAddress);
499 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
500 			return 0;
501 		return -EINVAL;
502 	}
503 
504 	implicit_fb = (get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_USAGE_MASK)
505 			== USB_ENDPOINT_USAGE_IMPLICIT_FB;
506 
507 	subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
508 						   alts, ep, !subs->direction,
509 						   implicit_fb ?
510 							SND_USB_ENDPOINT_TYPE_DATA :
511 							SND_USB_ENDPOINT_TYPE_SYNC);
512 
513 	if (!subs->sync_endpoint) {
514 		if (is_playback && attr == USB_ENDPOINT_SYNC_NONE)
515 			return 0;
516 		return -EINVAL;
517 	}
518 
519 	subs->sync_endpoint->is_implicit_feedback = implicit_fb;
520 
521 	subs->data_endpoint->sync_master = subs->sync_endpoint;
522 
523 	return 0;
524 }
525 
526 /*
527  * find a matching format and set up the interface
528  */
529 static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
530 {
531 	struct usb_device *dev = subs->dev;
532 	struct usb_host_interface *alts;
533 	struct usb_interface_descriptor *altsd;
534 	struct usb_interface *iface;
535 	int err;
536 
537 	iface = usb_ifnum_to_if(dev, fmt->iface);
538 	if (WARN_ON(!iface))
539 		return -EINVAL;
540 	alts = usb_altnum_to_altsetting(iface, fmt->altsetting);
541 	if (WARN_ON(!alts))
542 		return -EINVAL;
543 	altsd = get_iface_desc(alts);
544 
545 	if (fmt == subs->cur_audiofmt && !subs->need_setup_fmt)
546 		return 0;
547 
548 	/* close the old interface */
549 	if (subs->interface >= 0 && (subs->interface != fmt->iface || subs->need_setup_fmt)) {
550 		if (!subs->stream->chip->keep_iface) {
551 			err = usb_set_interface(subs->dev, subs->interface, 0);
552 			if (err < 0) {
553 				dev_err(&dev->dev,
554 					"%d:%d: return to setting 0 failed (%d)\n",
555 					fmt->iface, fmt->altsetting, err);
556 				return -EIO;
557 			}
558 		}
559 		subs->interface = -1;
560 		subs->altset_idx = 0;
561 	}
562 
563 	if (subs->need_setup_fmt)
564 		subs->need_setup_fmt = false;
565 
566 	/* set interface */
567 	if (iface->cur_altsetting != alts) {
568 		err = snd_usb_select_mode_quirk(subs, fmt);
569 		if (err < 0)
570 			return -EIO;
571 
572 		err = usb_set_interface(dev, fmt->iface, fmt->altsetting);
573 		if (err < 0) {
574 			dev_err(&dev->dev,
575 				"%d:%d: usb_set_interface failed (%d)\n",
576 				fmt->iface, fmt->altsetting, err);
577 			return -EIO;
578 		}
579 		dev_dbg(&dev->dev, "setting usb interface %d:%d\n",
580 			fmt->iface, fmt->altsetting);
581 		snd_usb_set_interface_quirk(dev);
582 	}
583 
584 	subs->interface = fmt->iface;
585 	subs->altset_idx = fmt->altset_idx;
586 	subs->data_endpoint = snd_usb_add_endpoint(subs->stream->chip,
587 						   alts, fmt->endpoint, subs->direction,
588 						   SND_USB_ENDPOINT_TYPE_DATA);
589 
590 	if (!subs->data_endpoint)
591 		return -EINVAL;
592 
593 	err = set_sync_endpoint(subs, fmt, dev, alts, altsd);
594 	if (err < 0)
595 		return err;
596 
597 	err = snd_usb_init_pitch(subs->stream->chip, fmt->iface, alts, fmt);
598 	if (err < 0)
599 		return err;
600 
601 	subs->cur_audiofmt = fmt;
602 
603 	snd_usb_set_format_quirk(subs, fmt);
604 
605 	return 0;
606 }
607 
608 /*
609  * Return the score of matching two audioformats.
610  * Veto the audioformat if:
611  * - It has no channels for some reason.
612  * - Requested PCM format is not supported.
613  * - Requested sample rate is not supported.
614  */
615 static int match_endpoint_audioformats(struct snd_usb_substream *subs,
616 				       struct audioformat *fp,
617 				       struct audioformat *match, int rate,
618 				       snd_pcm_format_t pcm_format)
619 {
620 	int i;
621 	int score = 0;
622 
623 	if (fp->channels < 1) {
624 		dev_dbg(&subs->dev->dev,
625 			"%s: (fmt @%p) no channels\n", __func__, fp);
626 		return 0;
627 	}
628 
629 	if (!(fp->formats & pcm_format_to_bits(pcm_format))) {
630 		dev_dbg(&subs->dev->dev,
631 			"%s: (fmt @%p) no match for format %d\n", __func__,
632 			fp, pcm_format);
633 		return 0;
634 	}
635 
636 	for (i = 0; i < fp->nr_rates; i++) {
637 		if (fp->rate_table[i] == rate) {
638 			score++;
639 			break;
640 		}
641 	}
642 	if (!score) {
643 		dev_dbg(&subs->dev->dev,
644 			"%s: (fmt @%p) no match for rate %d\n", __func__,
645 			fp, rate);
646 		return 0;
647 	}
648 
649 	if (fp->channels == match->channels)
650 		score++;
651 
652 	dev_dbg(&subs->dev->dev,
653 		"%s: (fmt @%p) score %d\n", __func__, fp, score);
654 
655 	return score;
656 }
657 
658 /*
659  * Configure the sync ep using the rate and pcm format of the data ep.
660  */
661 static int configure_sync_endpoint(struct snd_usb_substream *subs)
662 {
663 	int ret;
664 	struct audioformat *fp;
665 	struct audioformat *sync_fp = NULL;
666 	int cur_score = 0;
667 	int sync_period_bytes = subs->period_bytes;
668 	struct snd_usb_substream *sync_subs =
669 		&subs->stream->substream[subs->direction ^ 1];
670 
671 	if (subs->sync_endpoint->type != SND_USB_ENDPOINT_TYPE_DATA ||
672 	    !subs->stream)
673 		return snd_usb_endpoint_set_params(subs->sync_endpoint,
674 						   subs->pcm_format,
675 						   subs->channels,
676 						   subs->period_bytes,
677 						   0, 0,
678 						   subs->cur_rate,
679 						   subs->cur_audiofmt,
680 						   NULL);
681 
682 	/* Try to find the best matching audioformat. */
683 	list_for_each_entry(fp, &sync_subs->fmt_list, list) {
684 		int score = match_endpoint_audioformats(subs,
685 							fp, subs->cur_audiofmt,
686 			subs->cur_rate, subs->pcm_format);
687 
688 		if (score > cur_score) {
689 			sync_fp = fp;
690 			cur_score = score;
691 		}
692 	}
693 
694 	if (unlikely(sync_fp == NULL)) {
695 		dev_err(&subs->dev->dev,
696 			"%s: no valid audioformat for sync ep %x found\n",
697 			__func__, sync_subs->ep_num);
698 		return -EINVAL;
699 	}
700 
701 	/*
702 	 * Recalculate the period bytes if channel number differ between
703 	 * data and sync ep audioformat.
704 	 */
705 	if (sync_fp->channels != subs->channels) {
706 		sync_period_bytes = (subs->period_bytes / subs->channels) *
707 			sync_fp->channels;
708 		dev_dbg(&subs->dev->dev,
709 			"%s: adjusted sync ep period bytes (%d -> %d)\n",
710 			__func__, subs->period_bytes, sync_period_bytes);
711 	}
712 
713 	ret = snd_usb_endpoint_set_params(subs->sync_endpoint,
714 					  subs->pcm_format,
715 					  sync_fp->channels,
716 					  sync_period_bytes,
717 					  0, 0,
718 					  subs->cur_rate,
719 					  sync_fp,
720 					  NULL);
721 
722 	return ret;
723 }
724 
725 /*
726  * configure endpoint params
727  *
728  * called  during initial setup and upon resume
729  */
730 static int configure_endpoint(struct snd_usb_substream *subs)
731 {
732 	int ret;
733 
734 	/* format changed */
735 	stop_endpoints(subs);
736 	sync_pending_stops(subs);
737 	ret = snd_usb_endpoint_set_params(subs->data_endpoint,
738 					  subs->pcm_format,
739 					  subs->channels,
740 					  subs->period_bytes,
741 					  subs->period_frames,
742 					  subs->buffer_periods,
743 					  subs->cur_rate,
744 					  subs->cur_audiofmt,
745 					  subs->sync_endpoint);
746 	if (ret < 0)
747 		return ret;
748 
749 	if (subs->sync_endpoint)
750 		ret = configure_sync_endpoint(subs);
751 
752 	return ret;
753 }
754 
755 static int snd_usb_pcm_change_state(struct snd_usb_substream *subs, int state)
756 {
757 	int ret;
758 
759 	if (!subs->str_pd)
760 		return 0;
761 
762 	ret = snd_usb_power_domain_set(subs->stream->chip, subs->str_pd, state);
763 	if (ret < 0) {
764 		dev_err(&subs->dev->dev,
765 			"Cannot change Power Domain ID: %d to state: %d. Err: %d\n",
766 			subs->str_pd->pd_id, state, ret);
767 		return ret;
768 	}
769 
770 	return 0;
771 }
772 
773 int snd_usb_pcm_suspend(struct snd_usb_stream *as)
774 {
775 	int ret;
776 
777 	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D2);
778 	if (ret < 0)
779 		return ret;
780 
781 	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D2);
782 	if (ret < 0)
783 		return ret;
784 
785 	return 0;
786 }
787 
788 int snd_usb_pcm_resume(struct snd_usb_stream *as)
789 {
790 	int ret;
791 
792 	ret = snd_usb_pcm_change_state(&as->substream[0], UAC3_PD_STATE_D1);
793 	if (ret < 0)
794 		return ret;
795 
796 	ret = snd_usb_pcm_change_state(&as->substream[1], UAC3_PD_STATE_D1);
797 	if (ret < 0)
798 		return ret;
799 
800 	return 0;
801 }
802 
803 /*
804  * hw_params callback
805  *
806  * allocate a buffer and set the given audio format.
807  *
808  * so far we use a physically linear buffer although packetize transfer
809  * doesn't need a continuous area.
810  * if sg buffer is supported on the later version of alsa, we'll follow
811  * that.
812  */
813 static int snd_usb_hw_params(struct snd_pcm_substream *substream,
814 			     struct snd_pcm_hw_params *hw_params)
815 {
816 	struct snd_usb_substream *subs = substream->runtime->private_data;
817 	struct audioformat *fmt;
818 	int ret;
819 
820 	ret = snd_media_start_pipeline(subs);
821 	if (ret)
822 		return ret;
823 
824 	subs->pcm_format = params_format(hw_params);
825 	subs->period_bytes = params_period_bytes(hw_params);
826 	subs->period_frames = params_period_size(hw_params);
827 	subs->buffer_periods = params_periods(hw_params);
828 	subs->channels = params_channels(hw_params);
829 	subs->cur_rate = params_rate(hw_params);
830 
831 	fmt = find_format(subs);
832 	if (!fmt) {
833 		dev_dbg(&subs->dev->dev,
834 			"cannot set format: format = %#x, rate = %d, channels = %d\n",
835 			   subs->pcm_format, subs->cur_rate, subs->channels);
836 		ret = -EINVAL;
837 		goto stop_pipeline;
838 	}
839 
840 	ret = snd_usb_lock_shutdown(subs->stream->chip);
841 	if (ret < 0)
842 		goto stop_pipeline;
843 
844 	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
845 	if (ret < 0)
846 		goto unlock;
847 
848 	ret = set_format(subs, fmt);
849 	if (ret < 0)
850 		goto unlock;
851 
852 	subs->interface = fmt->iface;
853 	subs->altset_idx = fmt->altset_idx;
854 	subs->need_setup_ep = true;
855 
856  unlock:
857 	snd_usb_unlock_shutdown(subs->stream->chip);
858 	if (ret < 0)
859 		goto stop_pipeline;
860 	return ret;
861 
862  stop_pipeline:
863 	snd_media_stop_pipeline(subs);
864 	return ret;
865 }
866 
867 /*
868  * hw_free callback
869  *
870  * reset the audio format and release the buffer
871  */
872 static int snd_usb_hw_free(struct snd_pcm_substream *substream)
873 {
874 	struct snd_usb_substream *subs = substream->runtime->private_data;
875 
876 	snd_media_stop_pipeline(subs);
877 	subs->cur_audiofmt = NULL;
878 	subs->cur_rate = 0;
879 	subs->period_bytes = 0;
880 	if (!snd_usb_lock_shutdown(subs->stream->chip)) {
881 		stop_endpoints(subs);
882 		sync_pending_stops(subs);
883 		snd_usb_endpoint_deactivate(subs->sync_endpoint);
884 		snd_usb_endpoint_deactivate(subs->data_endpoint);
885 		snd_usb_unlock_shutdown(subs->stream->chip);
886 	}
887 
888 	return 0;
889 }
890 
891 /*
892  * prepare callback
893  *
894  * only a few subtle things...
895  */
896 static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
897 {
898 	struct snd_pcm_runtime *runtime = substream->runtime;
899 	struct snd_usb_substream *subs = runtime->private_data;
900 	struct usb_host_interface *alts;
901 	struct usb_interface *iface;
902 	int ret;
903 
904 	if (! subs->cur_audiofmt) {
905 		dev_err(&subs->dev->dev, "no format is specified!\n");
906 		return -ENXIO;
907 	}
908 
909 	ret = snd_usb_lock_shutdown(subs->stream->chip);
910 	if (ret < 0)
911 		return ret;
912 	if (snd_BUG_ON(!subs->data_endpoint)) {
913 		ret = -EIO;
914 		goto unlock;
915 	}
916 
917 	ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D0);
918 	if (ret < 0)
919 		goto unlock;
920 
921 	ret = set_format(subs, subs->cur_audiofmt);
922 	if (ret < 0)
923 		goto unlock;
924 
925 	if (subs->need_setup_ep) {
926 
927 		iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
928 		alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
929 		ret = snd_usb_init_sample_rate(subs->stream->chip,
930 					       subs->cur_audiofmt->iface,
931 					       alts,
932 					       subs->cur_audiofmt,
933 					       subs->cur_rate);
934 		if (ret < 0)
935 			goto unlock;
936 
937 		ret = configure_endpoint(subs);
938 		if (ret < 0)
939 			goto unlock;
940 		subs->need_setup_ep = false;
941 	}
942 
943 	/* some unit conversions in runtime */
944 	subs->data_endpoint->maxframesize =
945 		bytes_to_frames(runtime, subs->data_endpoint->maxpacksize);
946 	subs->data_endpoint->curframesize =
947 		bytes_to_frames(runtime, subs->data_endpoint->curpacksize);
948 
949 	/* reset the pointer */
950 	subs->hwptr_done = 0;
951 	subs->transfer_done = 0;
952 	subs->last_delay = 0;
953 	subs->last_frame_number = 0;
954 	runtime->delay = 0;
955 
956 	/* for playback, submit the URBs now; otherwise, the first hwptr_done
957 	 * updates for all URBs would happen at the same time when starting */
958 	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK)
959 		ret = start_endpoints(subs);
960 
961  unlock:
962 	snd_usb_unlock_shutdown(subs->stream->chip);
963 	return ret;
964 }
965 
966 static const struct snd_pcm_hardware snd_usb_hardware =
967 {
968 	.info =			SNDRV_PCM_INFO_MMAP |
969 				SNDRV_PCM_INFO_MMAP_VALID |
970 				SNDRV_PCM_INFO_BATCH |
971 				SNDRV_PCM_INFO_INTERLEAVED |
972 				SNDRV_PCM_INFO_BLOCK_TRANSFER |
973 				SNDRV_PCM_INFO_PAUSE,
974 	.buffer_bytes_max =	1024 * 1024,
975 	.period_bytes_min =	64,
976 	.period_bytes_max =	512 * 1024,
977 	.periods_min =		2,
978 	.periods_max =		1024,
979 };
980 
981 static int hw_check_valid_format(struct snd_usb_substream *subs,
982 				 struct snd_pcm_hw_params *params,
983 				 struct audioformat *fp)
984 {
985 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
986 	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
987 	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
988 	struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
989 	struct snd_mask check_fmts;
990 	unsigned int ptime;
991 
992 	/* check the format */
993 	snd_mask_none(&check_fmts);
994 	check_fmts.bits[0] = (u32)fp->formats;
995 	check_fmts.bits[1] = (u32)(fp->formats >> 32);
996 	snd_mask_intersect(&check_fmts, fmts);
997 	if (snd_mask_empty(&check_fmts)) {
998 		hwc_debug("   > check: no supported format %d\n", fp->format);
999 		return 0;
1000 	}
1001 	/* check the channels */
1002 	if (fp->channels < ct->min || fp->channels > ct->max) {
1003 		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
1004 		return 0;
1005 	}
1006 	/* check the rate is within the range */
1007 	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
1008 		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
1009 		return 0;
1010 	}
1011 	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
1012 		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
1013 		return 0;
1014 	}
1015 	/* check whether the period time is >= the data packet interval */
1016 	if (subs->speed != USB_SPEED_FULL) {
1017 		ptime = 125 * (1 << fp->datainterval);
1018 		if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
1019 			hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
1020 			return 0;
1021 		}
1022 	}
1023 	return 1;
1024 }
1025 
1026 static int hw_rule_rate(struct snd_pcm_hw_params *params,
1027 			struct snd_pcm_hw_rule *rule)
1028 {
1029 	struct snd_usb_substream *subs = rule->private;
1030 	struct audioformat *fp;
1031 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
1032 	unsigned int rmin, rmax;
1033 	int changed;
1034 
1035 	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
1036 	changed = 0;
1037 	rmin = rmax = 0;
1038 	list_for_each_entry(fp, &subs->fmt_list, list) {
1039 		if (!hw_check_valid_format(subs, params, fp))
1040 			continue;
1041 		if (changed++) {
1042 			if (rmin > fp->rate_min)
1043 				rmin = fp->rate_min;
1044 			if (rmax < fp->rate_max)
1045 				rmax = fp->rate_max;
1046 		} else {
1047 			rmin = fp->rate_min;
1048 			rmax = fp->rate_max;
1049 		}
1050 	}
1051 
1052 	if (!changed) {
1053 		hwc_debug("  --> get empty\n");
1054 		it->empty = 1;
1055 		return -EINVAL;
1056 	}
1057 
1058 	changed = 0;
1059 	if (it->min < rmin) {
1060 		it->min = rmin;
1061 		it->openmin = 0;
1062 		changed = 1;
1063 	}
1064 	if (it->max > rmax) {
1065 		it->max = rmax;
1066 		it->openmax = 0;
1067 		changed = 1;
1068 	}
1069 	if (snd_interval_checkempty(it)) {
1070 		it->empty = 1;
1071 		return -EINVAL;
1072 	}
1073 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
1074 	return changed;
1075 }
1076 
1077 
1078 static int hw_rule_channels(struct snd_pcm_hw_params *params,
1079 			    struct snd_pcm_hw_rule *rule)
1080 {
1081 	struct snd_usb_substream *subs = rule->private;
1082 	struct audioformat *fp;
1083 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
1084 	unsigned int rmin, rmax;
1085 	int changed;
1086 
1087 	hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
1088 	changed = 0;
1089 	rmin = rmax = 0;
1090 	list_for_each_entry(fp, &subs->fmt_list, list) {
1091 		if (!hw_check_valid_format(subs, params, fp))
1092 			continue;
1093 		if (changed++) {
1094 			if (rmin > fp->channels)
1095 				rmin = fp->channels;
1096 			if (rmax < fp->channels)
1097 				rmax = fp->channels;
1098 		} else {
1099 			rmin = fp->channels;
1100 			rmax = fp->channels;
1101 		}
1102 	}
1103 
1104 	if (!changed) {
1105 		hwc_debug("  --> get empty\n");
1106 		it->empty = 1;
1107 		return -EINVAL;
1108 	}
1109 
1110 	changed = 0;
1111 	if (it->min < rmin) {
1112 		it->min = rmin;
1113 		it->openmin = 0;
1114 		changed = 1;
1115 	}
1116 	if (it->max > rmax) {
1117 		it->max = rmax;
1118 		it->openmax = 0;
1119 		changed = 1;
1120 	}
1121 	if (snd_interval_checkempty(it)) {
1122 		it->empty = 1;
1123 		return -EINVAL;
1124 	}
1125 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
1126 	return changed;
1127 }
1128 
1129 static int hw_rule_format(struct snd_pcm_hw_params *params,
1130 			  struct snd_pcm_hw_rule *rule)
1131 {
1132 	struct snd_usb_substream *subs = rule->private;
1133 	struct audioformat *fp;
1134 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
1135 	u64 fbits;
1136 	u32 oldbits[2];
1137 	int changed;
1138 
1139 	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
1140 	fbits = 0;
1141 	list_for_each_entry(fp, &subs->fmt_list, list) {
1142 		if (!hw_check_valid_format(subs, params, fp))
1143 			continue;
1144 		fbits |= fp->formats;
1145 	}
1146 
1147 	oldbits[0] = fmt->bits[0];
1148 	oldbits[1] = fmt->bits[1];
1149 	fmt->bits[0] &= (u32)fbits;
1150 	fmt->bits[1] &= (u32)(fbits >> 32);
1151 	if (!fmt->bits[0] && !fmt->bits[1]) {
1152 		hwc_debug("  --> get empty\n");
1153 		return -EINVAL;
1154 	}
1155 	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
1156 	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
1157 	return changed;
1158 }
1159 
1160 static int hw_rule_period_time(struct snd_pcm_hw_params *params,
1161 			       struct snd_pcm_hw_rule *rule)
1162 {
1163 	struct snd_usb_substream *subs = rule->private;
1164 	struct audioformat *fp;
1165 	struct snd_interval *it;
1166 	unsigned char min_datainterval;
1167 	unsigned int pmin;
1168 	int changed;
1169 
1170 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
1171 	hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
1172 	min_datainterval = 0xff;
1173 	list_for_each_entry(fp, &subs->fmt_list, list) {
1174 		if (!hw_check_valid_format(subs, params, fp))
1175 			continue;
1176 		min_datainterval = min(min_datainterval, fp->datainterval);
1177 	}
1178 	if (min_datainterval == 0xff) {
1179 		hwc_debug("  --> get empty\n");
1180 		it->empty = 1;
1181 		return -EINVAL;
1182 	}
1183 	pmin = 125 * (1 << min_datainterval);
1184 	changed = 0;
1185 	if (it->min < pmin) {
1186 		it->min = pmin;
1187 		it->openmin = 0;
1188 		changed = 1;
1189 	}
1190 	if (snd_interval_checkempty(it)) {
1191 		it->empty = 1;
1192 		return -EINVAL;
1193 	}
1194 	hwc_debug("  --> (%u,%u) (changed = %d)\n", it->min, it->max, changed);
1195 	return changed;
1196 }
1197 
1198 /*
1199  *  If the device supports unusual bit rates, does the request meet these?
1200  */
1201 static int snd_usb_pcm_check_knot(struct snd_pcm_runtime *runtime,
1202 				  struct snd_usb_substream *subs)
1203 {
1204 	struct audioformat *fp;
1205 	int *rate_list;
1206 	int count = 0, needs_knot = 0;
1207 	int err;
1208 
1209 	kfree(subs->rate_list.list);
1210 	subs->rate_list.list = NULL;
1211 
1212 	list_for_each_entry(fp, &subs->fmt_list, list) {
1213 		if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)
1214 			return 0;
1215 		count += fp->nr_rates;
1216 		if (fp->rates & SNDRV_PCM_RATE_KNOT)
1217 			needs_knot = 1;
1218 	}
1219 	if (!needs_knot)
1220 		return 0;
1221 
1222 	subs->rate_list.list = rate_list =
1223 		kmalloc_array(count, sizeof(int), GFP_KERNEL);
1224 	if (!subs->rate_list.list)
1225 		return -ENOMEM;
1226 	subs->rate_list.count = count;
1227 	subs->rate_list.mask = 0;
1228 	count = 0;
1229 	list_for_each_entry(fp, &subs->fmt_list, list) {
1230 		int i;
1231 		for (i = 0; i < fp->nr_rates; i++)
1232 			rate_list[count++] = fp->rate_table[i];
1233 	}
1234 	err = snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1235 					 &subs->rate_list);
1236 	if (err < 0)
1237 		return err;
1238 
1239 	return 0;
1240 }
1241 
1242 
1243 /*
1244  * set up the runtime hardware information.
1245  */
1246 
1247 static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
1248 {
1249 	struct audioformat *fp;
1250 	unsigned int pt, ptmin;
1251 	int param_period_time_if_needed;
1252 	int err;
1253 
1254 	runtime->hw.formats = subs->formats;
1255 
1256 	runtime->hw.rate_min = 0x7fffffff;
1257 	runtime->hw.rate_max = 0;
1258 	runtime->hw.channels_min = 256;
1259 	runtime->hw.channels_max = 0;
1260 	runtime->hw.rates = 0;
1261 	ptmin = UINT_MAX;
1262 	/* check min/max rates and channels */
1263 	list_for_each_entry(fp, &subs->fmt_list, list) {
1264 		runtime->hw.rates |= fp->rates;
1265 		if (runtime->hw.rate_min > fp->rate_min)
1266 			runtime->hw.rate_min = fp->rate_min;
1267 		if (runtime->hw.rate_max < fp->rate_max)
1268 			runtime->hw.rate_max = fp->rate_max;
1269 		if (runtime->hw.channels_min > fp->channels)
1270 			runtime->hw.channels_min = fp->channels;
1271 		if (runtime->hw.channels_max < fp->channels)
1272 			runtime->hw.channels_max = fp->channels;
1273 		if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
1274 			/* FIXME: there might be more than one audio formats... */
1275 			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
1276 				fp->frame_size;
1277 		}
1278 		pt = 125 * (1 << fp->datainterval);
1279 		ptmin = min(ptmin, pt);
1280 	}
1281 
1282 	param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
1283 	if (subs->speed == USB_SPEED_FULL)
1284 		/* full speed devices have fixed data packet interval */
1285 		ptmin = 1000;
1286 	if (ptmin == 1000)
1287 		/* if period time doesn't go below 1 ms, no rules needed */
1288 		param_period_time_if_needed = -1;
1289 
1290 	err = snd_pcm_hw_constraint_minmax(runtime,
1291 					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1292 					   ptmin, UINT_MAX);
1293 	if (err < 0)
1294 		return err;
1295 
1296 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
1297 				  hw_rule_rate, subs,
1298 				  SNDRV_PCM_HW_PARAM_FORMAT,
1299 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1300 				  param_period_time_if_needed,
1301 				  -1);
1302 	if (err < 0)
1303 		return err;
1304 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
1305 				  hw_rule_channels, subs,
1306 				  SNDRV_PCM_HW_PARAM_FORMAT,
1307 				  SNDRV_PCM_HW_PARAM_RATE,
1308 				  param_period_time_if_needed,
1309 				  -1);
1310 	if (err < 0)
1311 		return err;
1312 	err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
1313 				  hw_rule_format, subs,
1314 				  SNDRV_PCM_HW_PARAM_RATE,
1315 				  SNDRV_PCM_HW_PARAM_CHANNELS,
1316 				  param_period_time_if_needed,
1317 				  -1);
1318 	if (err < 0)
1319 		return err;
1320 	if (param_period_time_if_needed >= 0) {
1321 		err = snd_pcm_hw_rule_add(runtime, 0,
1322 					  SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1323 					  hw_rule_period_time, subs,
1324 					  SNDRV_PCM_HW_PARAM_FORMAT,
1325 					  SNDRV_PCM_HW_PARAM_CHANNELS,
1326 					  SNDRV_PCM_HW_PARAM_RATE,
1327 					  -1);
1328 		if (err < 0)
1329 			return err;
1330 	}
1331 	err = snd_usb_pcm_check_knot(runtime, subs);
1332 	if (err < 0)
1333 		return err;
1334 
1335 	return snd_usb_autoresume(subs->stream->chip);
1336 }
1337 
1338 static int snd_usb_pcm_open(struct snd_pcm_substream *substream)
1339 {
1340 	int direction = substream->stream;
1341 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1342 	struct snd_pcm_runtime *runtime = substream->runtime;
1343 	struct snd_usb_substream *subs = &as->substream[direction];
1344 	int ret;
1345 
1346 	subs->interface = -1;
1347 	subs->altset_idx = 0;
1348 	runtime->hw = snd_usb_hardware;
1349 	runtime->private_data = subs;
1350 	subs->pcm_substream = substream;
1351 	/* runtime PM is also done there */
1352 
1353 	/* initialize DSD/DOP context */
1354 	subs->dsd_dop.byte_idx = 0;
1355 	subs->dsd_dop.channel = 0;
1356 	subs->dsd_dop.marker = 1;
1357 
1358 	ret = setup_hw_info(runtime, subs);
1359 	if (ret == 0) {
1360 		ret = snd_media_stream_init(subs, as->pcm, direction);
1361 		if (ret)
1362 			snd_usb_autosuspend(subs->stream->chip);
1363 	}
1364 	return ret;
1365 }
1366 
1367 static int snd_usb_pcm_close(struct snd_pcm_substream *substream)
1368 {
1369 	int direction = substream->stream;
1370 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
1371 	struct snd_usb_substream *subs = &as->substream[direction];
1372 	int ret;
1373 
1374 	snd_media_stop_pipeline(subs);
1375 
1376 	if (!as->chip->keep_iface &&
1377 	    subs->interface >= 0 &&
1378 	    !snd_usb_lock_shutdown(subs->stream->chip)) {
1379 		usb_set_interface(subs->dev, subs->interface, 0);
1380 		subs->interface = -1;
1381 		ret = snd_usb_pcm_change_state(subs, UAC3_PD_STATE_D1);
1382 		snd_usb_unlock_shutdown(subs->stream->chip);
1383 		if (ret < 0)
1384 			return ret;
1385 	}
1386 
1387 	subs->pcm_substream = NULL;
1388 	snd_usb_autosuspend(subs->stream->chip);
1389 
1390 	return 0;
1391 }
1392 
1393 /* Since a URB can handle only a single linear buffer, we must use double
1394  * buffering when the data to be transferred overflows the buffer boundary.
1395  * To avoid inconsistencies when updating hwptr_done, we use double buffering
1396  * for all URBs.
1397  */
1398 static void retire_capture_urb(struct snd_usb_substream *subs,
1399 			       struct urb *urb)
1400 {
1401 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1402 	unsigned int stride, frames, bytes, oldptr;
1403 	int i, period_elapsed = 0;
1404 	unsigned long flags;
1405 	unsigned char *cp;
1406 	int current_frame_number;
1407 
1408 	/* read frame number here, update pointer in critical section */
1409 	current_frame_number = usb_get_current_frame_number(subs->dev);
1410 
1411 	stride = runtime->frame_bits >> 3;
1412 
1413 	for (i = 0; i < urb->number_of_packets; i++) {
1414 		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset + subs->pkt_offset_adj;
1415 		if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
1416 			dev_dbg(&subs->dev->dev, "frame %d active: %d\n",
1417 				i, urb->iso_frame_desc[i].status);
1418 			// continue;
1419 		}
1420 		bytes = urb->iso_frame_desc[i].actual_length;
1421 		frames = bytes / stride;
1422 		if (!subs->txfr_quirk)
1423 			bytes = frames * stride;
1424 		if (bytes % (runtime->sample_bits >> 3) != 0) {
1425 			int oldbytes = bytes;
1426 			bytes = frames * stride;
1427 			dev_warn_ratelimited(&subs->dev->dev,
1428 				 "Corrected urb data len. %d->%d\n",
1429 							oldbytes, bytes);
1430 		}
1431 		/* update the current pointer */
1432 		spin_lock_irqsave(&subs->lock, flags);
1433 		oldptr = subs->hwptr_done;
1434 		subs->hwptr_done += bytes;
1435 		if (subs->hwptr_done >= runtime->buffer_size * stride)
1436 			subs->hwptr_done -= runtime->buffer_size * stride;
1437 		frames = (bytes + (oldptr % stride)) / stride;
1438 		subs->transfer_done += frames;
1439 		if (subs->transfer_done >= runtime->period_size) {
1440 			subs->transfer_done -= runtime->period_size;
1441 			period_elapsed = 1;
1442 		}
1443 		/* capture delay is by construction limited to one URB,
1444 		 * reset delays here
1445 		 */
1446 		runtime->delay = subs->last_delay = 0;
1447 
1448 		/* realign last_frame_number */
1449 		subs->last_frame_number = current_frame_number;
1450 		subs->last_frame_number &= 0xFF; /* keep 8 LSBs */
1451 
1452 		spin_unlock_irqrestore(&subs->lock, flags);
1453 		/* copy a data chunk */
1454 		if (oldptr + bytes > runtime->buffer_size * stride) {
1455 			unsigned int bytes1 =
1456 					runtime->buffer_size * stride - oldptr;
1457 			memcpy(runtime->dma_area + oldptr, cp, bytes1);
1458 			memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
1459 		} else {
1460 			memcpy(runtime->dma_area + oldptr, cp, bytes);
1461 		}
1462 	}
1463 
1464 	if (period_elapsed)
1465 		snd_pcm_period_elapsed(subs->pcm_substream);
1466 }
1467 
1468 static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
1469 					     struct urb *urb, unsigned int bytes)
1470 {
1471 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1472 	unsigned int stride = runtime->frame_bits >> 3;
1473 	unsigned int dst_idx = 0;
1474 	unsigned int src_idx = subs->hwptr_done;
1475 	unsigned int wrap = runtime->buffer_size * stride;
1476 	u8 *dst = urb->transfer_buffer;
1477 	u8 *src = runtime->dma_area;
1478 	u8 marker[] = { 0x05, 0xfa };
1479 
1480 	/*
1481 	 * The DSP DOP format defines a way to transport DSD samples over
1482 	 * normal PCM data endpoints. It requires stuffing of marker bytes
1483 	 * (0x05 and 0xfa, alternating per sample frame), and then expects
1484 	 * 2 additional bytes of actual payload. The whole frame is stored
1485 	 * LSB.
1486 	 *
1487 	 * Hence, for a stereo transport, the buffer layout looks like this,
1488 	 * where L refers to left channel samples and R to right.
1489 	 *
1490 	 *   L1 L2 0x05   R1 R2 0x05   L3 L4 0xfa  R3 R4 0xfa
1491 	 *   L5 L6 0x05   R5 R6 0x05   L7 L8 0xfa  R7 R8 0xfa
1492 	 *   .....
1493 	 *
1494 	 */
1495 
1496 	while (bytes--) {
1497 		if (++subs->dsd_dop.byte_idx == 3) {
1498 			/* frame boundary? */
1499 			dst[dst_idx++] = marker[subs->dsd_dop.marker];
1500 			src_idx += 2;
1501 			subs->dsd_dop.byte_idx = 0;
1502 
1503 			if (++subs->dsd_dop.channel % runtime->channels == 0) {
1504 				/* alternate the marker */
1505 				subs->dsd_dop.marker++;
1506 				subs->dsd_dop.marker %= ARRAY_SIZE(marker);
1507 				subs->dsd_dop.channel = 0;
1508 			}
1509 		} else {
1510 			/* stuff the DSD payload */
1511 			int idx = (src_idx + subs->dsd_dop.byte_idx - 1) % wrap;
1512 
1513 			if (subs->cur_audiofmt->dsd_bitrev)
1514 				dst[dst_idx++] = bitrev8(src[idx]);
1515 			else
1516 				dst[dst_idx++] = src[idx];
1517 
1518 			subs->hwptr_done++;
1519 		}
1520 	}
1521 	if (subs->hwptr_done >= runtime->buffer_size * stride)
1522 		subs->hwptr_done -= runtime->buffer_size * stride;
1523 }
1524 
1525 static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
1526 			int offset, int stride, unsigned int bytes)
1527 {
1528 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1529 
1530 	if (subs->hwptr_done + bytes > runtime->buffer_size * stride) {
1531 		/* err, the transferred area goes over buffer boundary. */
1532 		unsigned int bytes1 =
1533 			runtime->buffer_size * stride - subs->hwptr_done;
1534 		memcpy(urb->transfer_buffer + offset,
1535 		       runtime->dma_area + subs->hwptr_done, bytes1);
1536 		memcpy(urb->transfer_buffer + offset + bytes1,
1537 		       runtime->dma_area, bytes - bytes1);
1538 	} else {
1539 		memcpy(urb->transfer_buffer + offset,
1540 		       runtime->dma_area + subs->hwptr_done, bytes);
1541 	}
1542 	subs->hwptr_done += bytes;
1543 	if (subs->hwptr_done >= runtime->buffer_size * stride)
1544 		subs->hwptr_done -= runtime->buffer_size * stride;
1545 }
1546 
1547 static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
1548 				      struct urb *urb, int stride,
1549 				      unsigned int bytes)
1550 {
1551 	__le32 packet_length;
1552 	int i;
1553 
1554 	/* Put __le32 length descriptor at start of each packet. */
1555 	for (i = 0; i < urb->number_of_packets; i++) {
1556 		unsigned int length = urb->iso_frame_desc[i].length;
1557 		unsigned int offset = urb->iso_frame_desc[i].offset;
1558 
1559 		packet_length = cpu_to_le32(length);
1560 		offset += i * sizeof(packet_length);
1561 		urb->iso_frame_desc[i].offset = offset;
1562 		urb->iso_frame_desc[i].length += sizeof(packet_length);
1563 		memcpy(urb->transfer_buffer + offset,
1564 		       &packet_length, sizeof(packet_length));
1565 		copy_to_urb(subs, urb, offset + sizeof(packet_length),
1566 			    stride, length);
1567 	}
1568 	/* Adjust transfer size accordingly. */
1569 	bytes += urb->number_of_packets * sizeof(packet_length);
1570 	return bytes;
1571 }
1572 
1573 static void prepare_playback_urb(struct snd_usb_substream *subs,
1574 				 struct urb *urb)
1575 {
1576 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1577 	struct snd_usb_endpoint *ep = subs->data_endpoint;
1578 	struct snd_urb_ctx *ctx = urb->context;
1579 	unsigned int counts, frames, bytes;
1580 	int i, stride, period_elapsed = 0;
1581 	unsigned long flags;
1582 
1583 	stride = runtime->frame_bits >> 3;
1584 
1585 	frames = 0;
1586 	urb->number_of_packets = 0;
1587 	spin_lock_irqsave(&subs->lock, flags);
1588 	subs->frame_limit += ep->max_urb_frames;
1589 	for (i = 0; i < ctx->packets; i++) {
1590 		if (ctx->packet_size[i])
1591 			counts = ctx->packet_size[i];
1592 		else if (ep->sync_master)
1593 			counts = snd_usb_endpoint_slave_next_packet_size(ep);
1594 		else
1595 			counts = snd_usb_endpoint_next_packet_size(ep);
1596 
1597 		/* set up descriptor */
1598 		urb->iso_frame_desc[i].offset = frames * ep->stride;
1599 		urb->iso_frame_desc[i].length = counts * ep->stride;
1600 		frames += counts;
1601 		urb->number_of_packets++;
1602 		subs->transfer_done += counts;
1603 		if (subs->transfer_done >= runtime->period_size) {
1604 			subs->transfer_done -= runtime->period_size;
1605 			subs->frame_limit = 0;
1606 			period_elapsed = 1;
1607 			if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
1608 				if (subs->transfer_done > 0) {
1609 					/* FIXME: fill-max mode is not
1610 					 * supported yet */
1611 					frames -= subs->transfer_done;
1612 					counts -= subs->transfer_done;
1613 					urb->iso_frame_desc[i].length =
1614 						counts * ep->stride;
1615 					subs->transfer_done = 0;
1616 				}
1617 				i++;
1618 				if (i < ctx->packets) {
1619 					/* add a transfer delimiter */
1620 					urb->iso_frame_desc[i].offset =
1621 						frames * ep->stride;
1622 					urb->iso_frame_desc[i].length = 0;
1623 					urb->number_of_packets++;
1624 				}
1625 				break;
1626 			}
1627 		}
1628 		/* finish at the period boundary or after enough frames */
1629 		if ((period_elapsed ||
1630 				subs->transfer_done >= subs->frame_limit) &&
1631 		    !snd_usb_endpoint_implicit_feedback_sink(ep))
1632 			break;
1633 	}
1634 	bytes = frames * ep->stride;
1635 
1636 	if (unlikely(subs->pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
1637 		     subs->cur_audiofmt->dsd_dop)) {
1638 		fill_playback_urb_dsd_dop(subs, urb, bytes);
1639 	} else if (unlikely(subs->pcm_format == SNDRV_PCM_FORMAT_DSD_U8 &&
1640 			   subs->cur_audiofmt->dsd_bitrev)) {
1641 		/* bit-reverse the bytes */
1642 		u8 *buf = urb->transfer_buffer;
1643 		for (i = 0; i < bytes; i++) {
1644 			int idx = (subs->hwptr_done + i)
1645 				% (runtime->buffer_size * stride);
1646 			buf[i] = bitrev8(runtime->dma_area[idx]);
1647 		}
1648 
1649 		subs->hwptr_done += bytes;
1650 		if (subs->hwptr_done >= runtime->buffer_size * stride)
1651 			subs->hwptr_done -= runtime->buffer_size * stride;
1652 	} else {
1653 		/* usual PCM */
1654 		if (!subs->tx_length_quirk)
1655 			copy_to_urb(subs, urb, 0, stride, bytes);
1656 		else
1657 			bytes = copy_to_urb_quirk(subs, urb, stride, bytes);
1658 			/* bytes is now amount of outgoing data */
1659 	}
1660 
1661 	/* update delay with exact number of samples queued */
1662 	runtime->delay = subs->last_delay;
1663 	runtime->delay += frames;
1664 	subs->last_delay = runtime->delay;
1665 
1666 	/* realign last_frame_number */
1667 	subs->last_frame_number = usb_get_current_frame_number(subs->dev);
1668 	subs->last_frame_number &= 0xFF; /* keep 8 LSBs */
1669 
1670 	if (subs->trigger_tstamp_pending_update) {
1671 		/* this is the first actual URB submitted,
1672 		 * update trigger timestamp to reflect actual start time
1673 		 */
1674 		snd_pcm_gettime(runtime, &runtime->trigger_tstamp);
1675 		subs->trigger_tstamp_pending_update = false;
1676 	}
1677 
1678 	spin_unlock_irqrestore(&subs->lock, flags);
1679 	urb->transfer_buffer_length = bytes;
1680 	if (period_elapsed)
1681 		snd_pcm_period_elapsed(subs->pcm_substream);
1682 }
1683 
1684 /*
1685  * process after playback data complete
1686  * - decrease the delay count again
1687  */
1688 static void retire_playback_urb(struct snd_usb_substream *subs,
1689 			       struct urb *urb)
1690 {
1691 	unsigned long flags;
1692 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1693 	struct snd_usb_endpoint *ep = subs->data_endpoint;
1694 	int processed = urb->transfer_buffer_length / ep->stride;
1695 	int est_delay;
1696 
1697 	/* ignore the delay accounting when procssed=0 is given, i.e.
1698 	 * silent payloads are procssed before handling the actual data
1699 	 */
1700 	if (!processed)
1701 		return;
1702 
1703 	spin_lock_irqsave(&subs->lock, flags);
1704 	if (!subs->last_delay)
1705 		goto out; /* short path */
1706 
1707 	est_delay = snd_usb_pcm_delay(subs, runtime->rate);
1708 	/* update delay with exact number of samples played */
1709 	if (processed > subs->last_delay)
1710 		subs->last_delay = 0;
1711 	else
1712 		subs->last_delay -= processed;
1713 	runtime->delay = subs->last_delay;
1714 
1715 	/*
1716 	 * Report when delay estimate is off by more than 2ms.
1717 	 * The error should be lower than 2ms since the estimate relies
1718 	 * on two reads of a counter updated every ms.
1719 	 */
1720 	if (abs(est_delay - subs->last_delay) * 1000 > runtime->rate * 2)
1721 		dev_dbg_ratelimited(&subs->dev->dev,
1722 			"delay: estimated %d, actual %d\n",
1723 			est_delay, subs->last_delay);
1724 
1725 	if (!subs->running) {
1726 		/* update last_frame_number for delay counting here since
1727 		 * prepare_playback_urb won't be called during pause
1728 		 */
1729 		subs->last_frame_number =
1730 			usb_get_current_frame_number(subs->dev) & 0xff;
1731 	}
1732 
1733  out:
1734 	spin_unlock_irqrestore(&subs->lock, flags);
1735 }
1736 
1737 static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
1738 					      int cmd)
1739 {
1740 	struct snd_usb_substream *subs = substream->runtime->private_data;
1741 
1742 	switch (cmd) {
1743 	case SNDRV_PCM_TRIGGER_START:
1744 		subs->trigger_tstamp_pending_update = true;
1745 		/* fall through */
1746 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1747 		subs->data_endpoint->prepare_data_urb = prepare_playback_urb;
1748 		subs->data_endpoint->retire_data_urb = retire_playback_urb;
1749 		subs->running = 1;
1750 		return 0;
1751 	case SNDRV_PCM_TRIGGER_STOP:
1752 		stop_endpoints(subs);
1753 		subs->running = 0;
1754 		return 0;
1755 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1756 		subs->data_endpoint->prepare_data_urb = NULL;
1757 		/* keep retire_data_urb for delay calculation */
1758 		subs->data_endpoint->retire_data_urb = retire_playback_urb;
1759 		subs->running = 0;
1760 		return 0;
1761 	case SNDRV_PCM_TRIGGER_SUSPEND:
1762 		if (subs->stream->chip->setup_fmt_after_resume_quirk) {
1763 			stop_endpoints(subs);
1764 			subs->need_setup_fmt = true;
1765 			return 0;
1766 		}
1767 		break;
1768 	}
1769 
1770 	return -EINVAL;
1771 }
1772 
1773 static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
1774 					     int cmd)
1775 {
1776 	int err;
1777 	struct snd_usb_substream *subs = substream->runtime->private_data;
1778 
1779 	switch (cmd) {
1780 	case SNDRV_PCM_TRIGGER_START:
1781 		err = start_endpoints(subs);
1782 		if (err < 0)
1783 			return err;
1784 
1785 		subs->data_endpoint->retire_data_urb = retire_capture_urb;
1786 		subs->running = 1;
1787 		return 0;
1788 	case SNDRV_PCM_TRIGGER_STOP:
1789 		stop_endpoints(subs);
1790 		subs->data_endpoint->retire_data_urb = NULL;
1791 		subs->running = 0;
1792 		return 0;
1793 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1794 		subs->data_endpoint->retire_data_urb = NULL;
1795 		subs->running = 0;
1796 		return 0;
1797 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1798 		subs->data_endpoint->retire_data_urb = retire_capture_urb;
1799 		subs->running = 1;
1800 		return 0;
1801 	case SNDRV_PCM_TRIGGER_SUSPEND:
1802 		if (subs->stream->chip->setup_fmt_after_resume_quirk) {
1803 			stop_endpoints(subs);
1804 			subs->need_setup_fmt = true;
1805 			return 0;
1806 		}
1807 		break;
1808 	}
1809 
1810 	return -EINVAL;
1811 }
1812 
1813 static const struct snd_pcm_ops snd_usb_playback_ops = {
1814 	.open =		snd_usb_pcm_open,
1815 	.close =	snd_usb_pcm_close,
1816 	.hw_params =	snd_usb_hw_params,
1817 	.hw_free =	snd_usb_hw_free,
1818 	.prepare =	snd_usb_pcm_prepare,
1819 	.trigger =	snd_usb_substream_playback_trigger,
1820 	.sync_stop =	snd_usb_pcm_sync_stop,
1821 	.pointer =	snd_usb_pcm_pointer,
1822 };
1823 
1824 static const struct snd_pcm_ops snd_usb_capture_ops = {
1825 	.open =		snd_usb_pcm_open,
1826 	.close =	snd_usb_pcm_close,
1827 	.hw_params =	snd_usb_hw_params,
1828 	.hw_free =	snd_usb_hw_free,
1829 	.prepare =	snd_usb_pcm_prepare,
1830 	.trigger =	snd_usb_substream_capture_trigger,
1831 	.sync_stop =	snd_usb_pcm_sync_stop,
1832 	.pointer =	snd_usb_pcm_pointer,
1833 };
1834 
1835 void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
1836 {
1837 	const struct snd_pcm_ops *ops;
1838 
1839 	ops = stream == SNDRV_PCM_STREAM_PLAYBACK ?
1840 			&snd_usb_playback_ops : &snd_usb_capture_ops;
1841 	snd_pcm_set_ops(pcm, stream, ops);
1842 }
1843 
1844 void snd_usb_preallocate_buffer(struct snd_usb_substream *subs)
1845 {
1846 	struct snd_pcm *pcm = subs->stream->pcm;
1847 	struct snd_pcm_substream *s = pcm->streams[subs->direction].substream;
1848 	struct device *dev = subs->dev->bus->controller;
1849 
1850 	if (snd_usb_use_vmalloc)
1851 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_VMALLOC,
1852 					   NULL, 0, 0);
1853 	else
1854 		snd_pcm_set_managed_buffer(s, SNDRV_DMA_TYPE_DEV_SG,
1855 					   dev, 64*1024, 512*1024);
1856 }
1857