xref: /linux/sound/usb/endpoint.c (revision aaa44952bbd1d4db14a4d676bf9595bb5db7e7b0)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  */
4 
5 #include <linux/gfp.h>
6 #include <linux/init.h>
7 #include <linux/ratelimit.h>
8 #include <linux/usb.h>
9 #include <linux/usb/audio.h>
10 #include <linux/slab.h>
11 
12 #include <sound/core.h>
13 #include <sound/pcm.h>
14 #include <sound/pcm_params.h>
15 
16 #include "usbaudio.h"
17 #include "helper.h"
18 #include "card.h"
19 #include "endpoint.h"
20 #include "pcm.h"
21 #include "clock.h"
22 #include "quirks.h"
23 
24 enum {
25 	EP_STATE_STOPPED,
26 	EP_STATE_RUNNING,
27 	EP_STATE_STOPPING,
28 };
29 
30 /* interface refcounting */
31 struct snd_usb_iface_ref {
32 	unsigned char iface;
33 	bool need_setup;
34 	int opened;
35 	struct list_head list;
36 };
37 
38 /*
39  * snd_usb_endpoint is a model that abstracts everything related to an
40  * USB endpoint and its streaming.
41  *
42  * There are functions to activate and deactivate the streaming URBs and
43  * optional callbacks to let the pcm logic handle the actual content of the
44  * packets for playback and record. Thus, the bus streaming and the audio
45  * handlers are fully decoupled.
46  *
47  * There are two different types of endpoints in audio applications.
48  *
49  * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
50  * inbound and outbound traffic.
51  *
52  * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
53  * expect the payload to carry Q10.14 / Q16.16 formatted sync information
54  * (3 or 4 bytes).
55  *
56  * Each endpoint has to be configured prior to being used by calling
57  * snd_usb_endpoint_set_params().
58  *
59  * The model incorporates a reference counting, so that multiple users
60  * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
61  * only the first user will effectively start the URBs, and only the last
62  * one to stop it will tear the URBs down again.
63  */
64 
65 /*
66  * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
67  * this will overflow at approx 524 kHz
68  */
69 static inline unsigned get_usb_full_speed_rate(unsigned int rate)
70 {
71 	return ((rate << 13) + 62) / 125;
72 }
73 
74 /*
75  * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
76  * this will overflow at approx 4 MHz
77  */
78 static inline unsigned get_usb_high_speed_rate(unsigned int rate)
79 {
80 	return ((rate << 10) + 62) / 125;
81 }
82 
83 /*
84  * release a urb data
85  */
86 static void release_urb_ctx(struct snd_urb_ctx *u)
87 {
88 	if (u->buffer_size)
89 		usb_free_coherent(u->ep->chip->dev, u->buffer_size,
90 				  u->urb->transfer_buffer,
91 				  u->urb->transfer_dma);
92 	usb_free_urb(u->urb);
93 	u->urb = NULL;
94 }
95 
96 static const char *usb_error_string(int err)
97 {
98 	switch (err) {
99 	case -ENODEV:
100 		return "no device";
101 	case -ENOENT:
102 		return "endpoint not enabled";
103 	case -EPIPE:
104 		return "endpoint stalled";
105 	case -ENOSPC:
106 		return "not enough bandwidth";
107 	case -ESHUTDOWN:
108 		return "device disabled";
109 	case -EHOSTUNREACH:
110 		return "device suspended";
111 	case -EINVAL:
112 	case -EAGAIN:
113 	case -EFBIG:
114 	case -EMSGSIZE:
115 		return "internal error";
116 	default:
117 		return "unknown error";
118 	}
119 }
120 
121 static inline bool ep_state_running(struct snd_usb_endpoint *ep)
122 {
123 	return atomic_read(&ep->state) == EP_STATE_RUNNING;
124 }
125 
126 static inline bool ep_state_update(struct snd_usb_endpoint *ep, int old, int new)
127 {
128 	return atomic_cmpxchg(&ep->state, old, new) == old;
129 }
130 
131 /**
132  * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
133  *
134  * @ep: The snd_usb_endpoint
135  *
136  * Determine whether an endpoint is driven by an implicit feedback
137  * data endpoint source.
138  */
139 int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
140 {
141 	return  ep->implicit_fb_sync && usb_pipeout(ep->pipe);
142 }
143 
144 /*
145  * Return the number of samples to be sent in the next packet
146  * for streaming based on information derived from sync endpoints
147  *
148  * This won't be used for implicit feedback which takes the packet size
149  * returned from the sync source
150  */
151 static int slave_next_packet_size(struct snd_usb_endpoint *ep)
152 {
153 	unsigned long flags;
154 	int ret;
155 
156 	if (ep->fill_max)
157 		return ep->maxframesize;
158 
159 	spin_lock_irqsave(&ep->lock, flags);
160 	ep->phase = (ep->phase & 0xffff)
161 		+ (ep->freqm << ep->datainterval);
162 	ret = min(ep->phase >> 16, ep->maxframesize);
163 	spin_unlock_irqrestore(&ep->lock, flags);
164 
165 	return ret;
166 }
167 
168 /*
169  * Return the number of samples to be sent in the next packet
170  * for adaptive and synchronous endpoints
171  */
172 static int next_packet_size(struct snd_usb_endpoint *ep)
173 {
174 	int ret;
175 
176 	if (ep->fill_max)
177 		return ep->maxframesize;
178 
179 	ep->sample_accum += ep->sample_rem;
180 	if (ep->sample_accum >= ep->pps) {
181 		ep->sample_accum -= ep->pps;
182 		ret = ep->packsize[1];
183 	} else {
184 		ret = ep->packsize[0];
185 	}
186 
187 	return ret;
188 }
189 
190 /*
191  * snd_usb_endpoint_next_packet_size: Return the number of samples to be sent
192  * in the next packet
193  */
194 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep,
195 				      struct snd_urb_ctx *ctx, int idx)
196 {
197 	if (ctx->packet_size[idx])
198 		return ctx->packet_size[idx];
199 	else if (ep->sync_source)
200 		return slave_next_packet_size(ep);
201 	else
202 		return next_packet_size(ep);
203 }
204 
205 static void call_retire_callback(struct snd_usb_endpoint *ep,
206 				 struct urb *urb)
207 {
208 	struct snd_usb_substream *data_subs;
209 
210 	data_subs = READ_ONCE(ep->data_subs);
211 	if (data_subs && ep->retire_data_urb)
212 		ep->retire_data_urb(data_subs, urb);
213 }
214 
215 static void retire_outbound_urb(struct snd_usb_endpoint *ep,
216 				struct snd_urb_ctx *urb_ctx)
217 {
218 	call_retire_callback(ep, urb_ctx->urb);
219 }
220 
221 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
222 				    struct snd_usb_endpoint *sender,
223 				    const struct urb *urb);
224 
225 static void retire_inbound_urb(struct snd_usb_endpoint *ep,
226 			       struct snd_urb_ctx *urb_ctx)
227 {
228 	struct urb *urb = urb_ctx->urb;
229 	struct snd_usb_endpoint *sync_sink;
230 
231 	if (unlikely(ep->skip_packets > 0)) {
232 		ep->skip_packets--;
233 		return;
234 	}
235 
236 	sync_sink = READ_ONCE(ep->sync_sink);
237 	if (sync_sink)
238 		snd_usb_handle_sync_urb(sync_sink, ep, urb);
239 
240 	call_retire_callback(ep, urb);
241 }
242 
243 static void prepare_silent_urb(struct snd_usb_endpoint *ep,
244 			       struct snd_urb_ctx *ctx)
245 {
246 	struct urb *urb = ctx->urb;
247 	unsigned int offs = 0;
248 	unsigned int extra = 0;
249 	__le32 packet_length;
250 	int i;
251 
252 	/* For tx_length_quirk, put packet length at start of packet */
253 	if (ep->chip->tx_length_quirk)
254 		extra = sizeof(packet_length);
255 
256 	for (i = 0; i < ctx->packets; ++i) {
257 		unsigned int offset;
258 		unsigned int length;
259 		int counts;
260 
261 		counts = snd_usb_endpoint_next_packet_size(ep, ctx, i);
262 		length = counts * ep->stride; /* number of silent bytes */
263 		offset = offs * ep->stride + extra * i;
264 		urb->iso_frame_desc[i].offset = offset;
265 		urb->iso_frame_desc[i].length = length + extra;
266 		if (extra) {
267 			packet_length = cpu_to_le32(length);
268 			memcpy(urb->transfer_buffer + offset,
269 			       &packet_length, sizeof(packet_length));
270 		}
271 		memset(urb->transfer_buffer + offset + extra,
272 		       ep->silence_value, length);
273 		offs += counts;
274 	}
275 
276 	urb->number_of_packets = ctx->packets;
277 	urb->transfer_buffer_length = offs * ep->stride + ctx->packets * extra;
278 }
279 
280 /*
281  * Prepare a PLAYBACK urb for submission to the bus.
282  */
283 static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
284 				 struct snd_urb_ctx *ctx)
285 {
286 	struct urb *urb = ctx->urb;
287 	unsigned char *cp = urb->transfer_buffer;
288 	struct snd_usb_substream *data_subs;
289 
290 	urb->dev = ep->chip->dev; /* we need to set this at each time */
291 
292 	switch (ep->type) {
293 	case SND_USB_ENDPOINT_TYPE_DATA:
294 		data_subs = READ_ONCE(ep->data_subs);
295 		if (data_subs && ep->prepare_data_urb)
296 			ep->prepare_data_urb(data_subs, urb);
297 		else /* no data provider, so send silence */
298 			prepare_silent_urb(ep, ctx);
299 		break;
300 
301 	case SND_USB_ENDPOINT_TYPE_SYNC:
302 		if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
303 			/*
304 			 * fill the length and offset of each urb descriptor.
305 			 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
306 			 */
307 			urb->iso_frame_desc[0].length = 4;
308 			urb->iso_frame_desc[0].offset = 0;
309 			cp[0] = ep->freqn;
310 			cp[1] = ep->freqn >> 8;
311 			cp[2] = ep->freqn >> 16;
312 			cp[3] = ep->freqn >> 24;
313 		} else {
314 			/*
315 			 * fill the length and offset of each urb descriptor.
316 			 * the fixed 10.14 frequency is passed through the pipe.
317 			 */
318 			urb->iso_frame_desc[0].length = 3;
319 			urb->iso_frame_desc[0].offset = 0;
320 			cp[0] = ep->freqn >> 2;
321 			cp[1] = ep->freqn >> 10;
322 			cp[2] = ep->freqn >> 18;
323 		}
324 
325 		break;
326 	}
327 }
328 
329 /*
330  * Prepare a CAPTURE or SYNC urb for submission to the bus.
331  */
332 static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep,
333 				       struct snd_urb_ctx *urb_ctx)
334 {
335 	int i, offs;
336 	struct urb *urb = urb_ctx->urb;
337 
338 	urb->dev = ep->chip->dev; /* we need to set this at each time */
339 
340 	switch (ep->type) {
341 	case SND_USB_ENDPOINT_TYPE_DATA:
342 		offs = 0;
343 		for (i = 0; i < urb_ctx->packets; i++) {
344 			urb->iso_frame_desc[i].offset = offs;
345 			urb->iso_frame_desc[i].length = ep->curpacksize;
346 			offs += ep->curpacksize;
347 		}
348 
349 		urb->transfer_buffer_length = offs;
350 		urb->number_of_packets = urb_ctx->packets;
351 		break;
352 
353 	case SND_USB_ENDPOINT_TYPE_SYNC:
354 		urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
355 		urb->iso_frame_desc[0].offset = 0;
356 		break;
357 	}
358 }
359 
360 /* notify an error as XRUN to the assigned PCM data substream */
361 static void notify_xrun(struct snd_usb_endpoint *ep)
362 {
363 	struct snd_usb_substream *data_subs;
364 
365 	data_subs = READ_ONCE(ep->data_subs);
366 	if (data_subs && data_subs->pcm_substream)
367 		snd_pcm_stop_xrun(data_subs->pcm_substream);
368 }
369 
370 static struct snd_usb_packet_info *
371 next_packet_fifo_enqueue(struct snd_usb_endpoint *ep)
372 {
373 	struct snd_usb_packet_info *p;
374 
375 	p = ep->next_packet + (ep->next_packet_head + ep->next_packet_queued) %
376 		ARRAY_SIZE(ep->next_packet);
377 	ep->next_packet_queued++;
378 	return p;
379 }
380 
381 static struct snd_usb_packet_info *
382 next_packet_fifo_dequeue(struct snd_usb_endpoint *ep)
383 {
384 	struct snd_usb_packet_info *p;
385 
386 	p = ep->next_packet + ep->next_packet_head;
387 	ep->next_packet_head++;
388 	ep->next_packet_head %= ARRAY_SIZE(ep->next_packet);
389 	ep->next_packet_queued--;
390 	return p;
391 }
392 
393 /*
394  * Send output urbs that have been prepared previously. URBs are dequeued
395  * from ep->ready_playback_urbs and in case there aren't any available
396  * or there are no packets that have been prepared, this function does
397  * nothing.
398  *
399  * The reason why the functionality of sending and preparing URBs is separated
400  * is that host controllers don't guarantee the order in which they return
401  * inbound and outbound packets to their submitters.
402  *
403  * This function is only used for implicit feedback endpoints. For endpoints
404  * driven by dedicated sync endpoints, URBs are immediately re-submitted
405  * from their completion handler.
406  */
407 static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
408 {
409 	while (ep_state_running(ep)) {
410 
411 		unsigned long flags;
412 		struct snd_usb_packet_info *packet;
413 		struct snd_urb_ctx *ctx = NULL;
414 		int err, i;
415 
416 		spin_lock_irqsave(&ep->lock, flags);
417 		if (ep->next_packet_queued > 0 &&
418 		    !list_empty(&ep->ready_playback_urbs)) {
419 			/* take URB out of FIFO */
420 			ctx = list_first_entry(&ep->ready_playback_urbs,
421 					       struct snd_urb_ctx, ready_list);
422 			list_del_init(&ctx->ready_list);
423 
424 			packet = next_packet_fifo_dequeue(ep);
425 		}
426 		spin_unlock_irqrestore(&ep->lock, flags);
427 
428 		if (ctx == NULL)
429 			return;
430 
431 		/* copy over the length information */
432 		for (i = 0; i < packet->packets; i++)
433 			ctx->packet_size[i] = packet->packet_size[i];
434 
435 		/* call the data handler to fill in playback data */
436 		prepare_outbound_urb(ep, ctx);
437 
438 		err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
439 		if (err < 0) {
440 			usb_audio_err(ep->chip,
441 				      "Unable to submit urb #%d: %d at %s\n",
442 				      ctx->index, err, __func__);
443 			notify_xrun(ep);
444 			return;
445 		}
446 
447 		set_bit(ctx->index, &ep->active_mask);
448 	}
449 }
450 
451 /*
452  * complete callback for urbs
453  */
454 static void snd_complete_urb(struct urb *urb)
455 {
456 	struct snd_urb_ctx *ctx = urb->context;
457 	struct snd_usb_endpoint *ep = ctx->ep;
458 	unsigned long flags;
459 	int err;
460 
461 	if (unlikely(urb->status == -ENOENT ||		/* unlinked */
462 		     urb->status == -ENODEV ||		/* device removed */
463 		     urb->status == -ECONNRESET ||	/* unlinked */
464 		     urb->status == -ESHUTDOWN))	/* device disabled */
465 		goto exit_clear;
466 	/* device disconnected */
467 	if (unlikely(atomic_read(&ep->chip->shutdown)))
468 		goto exit_clear;
469 
470 	if (unlikely(!ep_state_running(ep)))
471 		goto exit_clear;
472 
473 	if (usb_pipeout(ep->pipe)) {
474 		retire_outbound_urb(ep, ctx);
475 		/* can be stopped during retire callback */
476 		if (unlikely(!ep_state_running(ep)))
477 			goto exit_clear;
478 
479 		if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
480 			spin_lock_irqsave(&ep->lock, flags);
481 			list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
482 			clear_bit(ctx->index, &ep->active_mask);
483 			spin_unlock_irqrestore(&ep->lock, flags);
484 			queue_pending_output_urbs(ep);
485 			return;
486 		}
487 
488 		prepare_outbound_urb(ep, ctx);
489 		/* can be stopped during prepare callback */
490 		if (unlikely(!ep_state_running(ep)))
491 			goto exit_clear;
492 	} else {
493 		retire_inbound_urb(ep, ctx);
494 		/* can be stopped during retire callback */
495 		if (unlikely(!ep_state_running(ep)))
496 			goto exit_clear;
497 
498 		prepare_inbound_urb(ep, ctx);
499 	}
500 
501 	err = usb_submit_urb(urb, GFP_ATOMIC);
502 	if (err == 0)
503 		return;
504 
505 	usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
506 	notify_xrun(ep);
507 
508 exit_clear:
509 	clear_bit(ctx->index, &ep->active_mask);
510 }
511 
512 /*
513  * Find or create a refcount object for the given interface
514  *
515  * The objects are released altogether in snd_usb_endpoint_free_all()
516  */
517 static struct snd_usb_iface_ref *
518 iface_ref_find(struct snd_usb_audio *chip, int iface)
519 {
520 	struct snd_usb_iface_ref *ip;
521 
522 	list_for_each_entry(ip, &chip->iface_ref_list, list)
523 		if (ip->iface == iface)
524 			return ip;
525 
526 	ip = kzalloc(sizeof(*ip), GFP_KERNEL);
527 	if (!ip)
528 		return NULL;
529 	ip->iface = iface;
530 	list_add_tail(&ip->list, &chip->iface_ref_list);
531 	return ip;
532 }
533 
534 /*
535  * Get the existing endpoint object corresponding EP
536  * Returns NULL if not present.
537  */
538 struct snd_usb_endpoint *
539 snd_usb_get_endpoint(struct snd_usb_audio *chip, int ep_num)
540 {
541 	struct snd_usb_endpoint *ep;
542 
543 	list_for_each_entry(ep, &chip->ep_list, list) {
544 		if (ep->ep_num == ep_num)
545 			return ep;
546 	}
547 
548 	return NULL;
549 }
550 
551 #define ep_type_name(type) \
552 	(type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync")
553 
554 /**
555  * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
556  *
557  * @chip: The chip
558  * @ep_num: The number of the endpoint to use
559  * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
560  *
561  * If the requested endpoint has not been added to the given chip before,
562  * a new instance is created.
563  *
564  * Returns zero on success or a negative error code.
565  *
566  * New endpoints will be added to chip->ep_list and freed by
567  * calling snd_usb_endpoint_free_all().
568  *
569  * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
570  * bNumEndpoints > 1 beforehand.
571  */
572 int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type)
573 {
574 	struct snd_usb_endpoint *ep;
575 	bool is_playback;
576 
577 	ep = snd_usb_get_endpoint(chip, ep_num);
578 	if (ep)
579 		return 0;
580 
581 	usb_audio_dbg(chip, "Creating new %s endpoint #%x\n",
582 		      ep_type_name(type),
583 		      ep_num);
584 	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
585 	if (!ep)
586 		return -ENOMEM;
587 
588 	ep->chip = chip;
589 	spin_lock_init(&ep->lock);
590 	ep->type = type;
591 	ep->ep_num = ep_num;
592 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
593 
594 	is_playback = ((ep_num & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT);
595 	ep_num &= USB_ENDPOINT_NUMBER_MASK;
596 	if (is_playback)
597 		ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
598 	else
599 		ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
600 
601 	list_add_tail(&ep->list, &chip->ep_list);
602 	return 0;
603 }
604 
605 /* Set up syncinterval and maxsyncsize for a sync EP */
606 static void endpoint_set_syncinterval(struct snd_usb_audio *chip,
607 				      struct snd_usb_endpoint *ep)
608 {
609 	struct usb_host_interface *alts;
610 	struct usb_endpoint_descriptor *desc;
611 
612 	alts = snd_usb_get_host_interface(chip, ep->iface, ep->altsetting);
613 	if (!alts)
614 		return;
615 
616 	desc = get_endpoint(alts, ep->ep_idx);
617 	if (desc->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
618 	    desc->bRefresh >= 1 && desc->bRefresh <= 9)
619 		ep->syncinterval = desc->bRefresh;
620 	else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
621 		ep->syncinterval = 1;
622 	else if (desc->bInterval >= 1 && desc->bInterval <= 16)
623 		ep->syncinterval = desc->bInterval - 1;
624 	else
625 		ep->syncinterval = 3;
626 
627 	ep->syncmaxsize = le16_to_cpu(desc->wMaxPacketSize);
628 }
629 
630 static bool endpoint_compatible(struct snd_usb_endpoint *ep,
631 				const struct audioformat *fp,
632 				const struct snd_pcm_hw_params *params)
633 {
634 	if (!ep->opened)
635 		return false;
636 	if (ep->cur_audiofmt != fp)
637 		return false;
638 	if (ep->cur_rate != params_rate(params) ||
639 	    ep->cur_format != params_format(params) ||
640 	    ep->cur_period_frames != params_period_size(params) ||
641 	    ep->cur_buffer_periods != params_periods(params))
642 		return false;
643 	return true;
644 }
645 
646 /*
647  * Check whether the given fp and hw params are compatbile with the current
648  * setup of the target EP for implicit feedback sync
649  */
650 bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip,
651 				 struct snd_usb_endpoint *ep,
652 				 const struct audioformat *fp,
653 				 const struct snd_pcm_hw_params *params)
654 {
655 	bool ret;
656 
657 	mutex_lock(&chip->mutex);
658 	ret = endpoint_compatible(ep, fp, params);
659 	mutex_unlock(&chip->mutex);
660 	return ret;
661 }
662 
663 /*
664  * snd_usb_endpoint_open: Open the endpoint
665  *
666  * Called from hw_params to assign the endpoint to the substream.
667  * It's reference-counted, and only the first opener is allowed to set up
668  * arbitrary parameters.  The later opener must be compatible with the
669  * former opened parameters.
670  * The endpoint needs to be closed via snd_usb_endpoint_close() later.
671  *
672  * Note that this function doesn't configure the endpoint.  The substream
673  * needs to set it up later via snd_usb_endpoint_configure().
674  */
675 struct snd_usb_endpoint *
676 snd_usb_endpoint_open(struct snd_usb_audio *chip,
677 		      const struct audioformat *fp,
678 		      const struct snd_pcm_hw_params *params,
679 		      bool is_sync_ep)
680 {
681 	struct snd_usb_endpoint *ep;
682 	int ep_num = is_sync_ep ? fp->sync_ep : fp->endpoint;
683 
684 	mutex_lock(&chip->mutex);
685 	ep = snd_usb_get_endpoint(chip, ep_num);
686 	if (!ep) {
687 		usb_audio_err(chip, "Cannot find EP 0x%x to open\n", ep_num);
688 		goto unlock;
689 	}
690 
691 	if (!ep->opened) {
692 		if (is_sync_ep) {
693 			ep->iface = fp->sync_iface;
694 			ep->altsetting = fp->sync_altsetting;
695 			ep->ep_idx = fp->sync_ep_idx;
696 		} else {
697 			ep->iface = fp->iface;
698 			ep->altsetting = fp->altsetting;
699 			ep->ep_idx = fp->ep_idx;
700 		}
701 		usb_audio_dbg(chip, "Open EP 0x%x, iface=%d:%d, idx=%d\n",
702 			      ep_num, ep->iface, ep->altsetting, ep->ep_idx);
703 
704 		ep->iface_ref = iface_ref_find(chip, ep->iface);
705 		if (!ep->iface_ref) {
706 			ep = NULL;
707 			goto unlock;
708 		}
709 
710 		ep->cur_audiofmt = fp;
711 		ep->cur_channels = fp->channels;
712 		ep->cur_rate = params_rate(params);
713 		ep->cur_format = params_format(params);
714 		ep->cur_frame_bytes = snd_pcm_format_physical_width(ep->cur_format) *
715 			ep->cur_channels / 8;
716 		ep->cur_period_frames = params_period_size(params);
717 		ep->cur_period_bytes = ep->cur_period_frames * ep->cur_frame_bytes;
718 		ep->cur_buffer_periods = params_periods(params);
719 
720 		if (ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
721 			endpoint_set_syncinterval(chip, ep);
722 
723 		ep->implicit_fb_sync = fp->implicit_fb;
724 		ep->need_setup = true;
725 
726 		usb_audio_dbg(chip, "  channels=%d, rate=%d, format=%s, period_bytes=%d, periods=%d, implicit_fb=%d\n",
727 			      ep->cur_channels, ep->cur_rate,
728 			      snd_pcm_format_name(ep->cur_format),
729 			      ep->cur_period_bytes, ep->cur_buffer_periods,
730 			      ep->implicit_fb_sync);
731 
732 	} else {
733 		if (WARN_ON(!ep->iface_ref)) {
734 			ep = NULL;
735 			goto unlock;
736 		}
737 
738 		if (!endpoint_compatible(ep, fp, params)) {
739 			usb_audio_err(chip, "Incompatible EP setup for 0x%x\n",
740 				      ep_num);
741 			ep = NULL;
742 			goto unlock;
743 		}
744 
745 		usb_audio_dbg(chip, "Reopened EP 0x%x (count %d)\n",
746 			      ep_num, ep->opened);
747 	}
748 
749 	if (!ep->iface_ref->opened++)
750 		ep->iface_ref->need_setup = true;
751 
752 	ep->opened++;
753 
754  unlock:
755 	mutex_unlock(&chip->mutex);
756 	return ep;
757 }
758 
759 /*
760  * snd_usb_endpoint_set_sync: Link data and sync endpoints
761  *
762  * Pass NULL to sync_ep to unlink again
763  */
764 void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
765 			       struct snd_usb_endpoint *data_ep,
766 			       struct snd_usb_endpoint *sync_ep)
767 {
768 	data_ep->sync_source = sync_ep;
769 }
770 
771 /*
772  * Set data endpoint callbacks and the assigned data stream
773  *
774  * Called at PCM trigger and cleanups.
775  * Pass NULL to deactivate each callback.
776  */
777 void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
778 				   void (*prepare)(struct snd_usb_substream *subs,
779 						   struct urb *urb),
780 				   void (*retire)(struct snd_usb_substream *subs,
781 						  struct urb *urb),
782 				   struct snd_usb_substream *data_subs)
783 {
784 	ep->prepare_data_urb = prepare;
785 	ep->retire_data_urb = retire;
786 	WRITE_ONCE(ep->data_subs, data_subs);
787 }
788 
789 static int endpoint_set_interface(struct snd_usb_audio *chip,
790 				  struct snd_usb_endpoint *ep,
791 				  bool set)
792 {
793 	int altset = set ? ep->altsetting : 0;
794 	int err;
795 
796 	usb_audio_dbg(chip, "Setting usb interface %d:%d for EP 0x%x\n",
797 		      ep->iface, altset, ep->ep_num);
798 	err = usb_set_interface(chip->dev, ep->iface, altset);
799 	if (err < 0) {
800 		usb_audio_err(chip, "%d:%d: usb_set_interface failed (%d)\n",
801 			      ep->iface, altset, err);
802 		return err;
803 	}
804 
805 	snd_usb_set_interface_quirk(chip);
806 	return 0;
807 }
808 
809 /*
810  * snd_usb_endpoint_close: Close the endpoint
811  *
812  * Unreference the already opened endpoint via snd_usb_endpoint_open().
813  */
814 void snd_usb_endpoint_close(struct snd_usb_audio *chip,
815 			    struct snd_usb_endpoint *ep)
816 {
817 	mutex_lock(&chip->mutex);
818 	usb_audio_dbg(chip, "Closing EP 0x%x (count %d)\n",
819 		      ep->ep_num, ep->opened);
820 
821 	if (!--ep->iface_ref->opened)
822 		endpoint_set_interface(chip, ep, false);
823 
824 	if (!--ep->opened) {
825 		ep->iface = 0;
826 		ep->altsetting = 0;
827 		ep->cur_audiofmt = NULL;
828 		ep->cur_rate = 0;
829 		ep->iface_ref = NULL;
830 		usb_audio_dbg(chip, "EP 0x%x closed\n", ep->ep_num);
831 	}
832 	mutex_unlock(&chip->mutex);
833 }
834 
835 /* Prepare for suspening EP, called from the main suspend handler */
836 void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep)
837 {
838 	ep->need_setup = true;
839 	if (ep->iface_ref)
840 		ep->iface_ref->need_setup = true;
841 }
842 
843 /*
844  *  wait until all urbs are processed.
845  */
846 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
847 {
848 	unsigned long end_time = jiffies + msecs_to_jiffies(1000);
849 	int alive;
850 
851 	if (atomic_read(&ep->state) != EP_STATE_STOPPING)
852 		return 0;
853 
854 	do {
855 		alive = bitmap_weight(&ep->active_mask, ep->nurbs);
856 		if (!alive)
857 			break;
858 
859 		schedule_timeout_uninterruptible(1);
860 	} while (time_before(jiffies, end_time));
861 
862 	if (alive)
863 		usb_audio_err(ep->chip,
864 			"timeout: still %d active urbs on EP #%x\n",
865 			alive, ep->ep_num);
866 
867 	if (ep_state_update(ep, EP_STATE_STOPPING, EP_STATE_STOPPED)) {
868 		ep->sync_sink = NULL;
869 		snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
870 	}
871 
872 	return 0;
873 }
874 
875 /* sync the pending stop operation;
876  * this function itself doesn't trigger the stop operation
877  */
878 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
879 {
880 	if (ep)
881 		wait_clear_urbs(ep);
882 }
883 
884 /*
885  * Stop active urbs
886  *
887  * This function moves the EP to STOPPING state if it's being RUNNING.
888  */
889 static int stop_urbs(struct snd_usb_endpoint *ep, bool force)
890 {
891 	unsigned int i;
892 
893 	if (!force && atomic_read(&ep->running))
894 		return -EBUSY;
895 
896 	if (!ep_state_update(ep, EP_STATE_RUNNING, EP_STATE_STOPPING))
897 		return 0;
898 
899 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
900 	ep->next_packet_head = 0;
901 	ep->next_packet_queued = 0;
902 
903 	for (i = 0; i < ep->nurbs; i++) {
904 		if (test_bit(i, &ep->active_mask)) {
905 			if (!test_and_set_bit(i, &ep->unlink_mask)) {
906 				struct urb *u = ep->urb[i].urb;
907 				usb_unlink_urb(u);
908 			}
909 		}
910 	}
911 
912 	return 0;
913 }
914 
915 /*
916  * release an endpoint's urbs
917  */
918 static int release_urbs(struct snd_usb_endpoint *ep, bool force)
919 {
920 	int i, err;
921 
922 	/* route incoming urbs to nirvana */
923 	snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
924 
925 	/* stop and unlink urbs */
926 	err = stop_urbs(ep, force);
927 	if (err)
928 		return err;
929 
930 	wait_clear_urbs(ep);
931 
932 	for (i = 0; i < ep->nurbs; i++)
933 		release_urb_ctx(&ep->urb[i]);
934 
935 	usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
936 			  ep->syncbuf, ep->sync_dma);
937 
938 	ep->syncbuf = NULL;
939 	ep->nurbs = 0;
940 	return 0;
941 }
942 
943 /*
944  * configure a data endpoint
945  */
946 static int data_ep_set_params(struct snd_usb_endpoint *ep)
947 {
948 	struct snd_usb_audio *chip = ep->chip;
949 	unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
950 	unsigned int max_packs_per_period, urbs_per_period, urb_packs;
951 	unsigned int max_urbs, i;
952 	const struct audioformat *fmt = ep->cur_audiofmt;
953 	int frame_bits = ep->cur_frame_bytes * 8;
954 	int tx_length_quirk = (chip->tx_length_quirk &&
955 			       usb_pipeout(ep->pipe));
956 
957 	usb_audio_dbg(chip, "Setting params for data EP 0x%x, pipe 0x%x\n",
958 		      ep->ep_num, ep->pipe);
959 
960 	if (ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
961 		/*
962 		 * When operating in DSD DOP mode, the size of a sample frame
963 		 * in hardware differs from the actual physical format width
964 		 * because we need to make room for the DOP markers.
965 		 */
966 		frame_bits += ep->cur_channels << 3;
967 	}
968 
969 	ep->datainterval = fmt->datainterval;
970 	ep->stride = frame_bits >> 3;
971 
972 	switch (ep->cur_format) {
973 	case SNDRV_PCM_FORMAT_U8:
974 		ep->silence_value = 0x80;
975 		break;
976 	case SNDRV_PCM_FORMAT_DSD_U8:
977 	case SNDRV_PCM_FORMAT_DSD_U16_LE:
978 	case SNDRV_PCM_FORMAT_DSD_U32_LE:
979 	case SNDRV_PCM_FORMAT_DSD_U16_BE:
980 	case SNDRV_PCM_FORMAT_DSD_U32_BE:
981 		ep->silence_value = 0x69;
982 		break;
983 	default:
984 		ep->silence_value = 0;
985 	}
986 
987 	/* assume max. frequency is 50% higher than nominal */
988 	ep->freqmax = ep->freqn + (ep->freqn >> 1);
989 	/* Round up freqmax to nearest integer in order to calculate maximum
990 	 * packet size, which must represent a whole number of frames.
991 	 * This is accomplished by adding 0x0.ffff before converting the
992 	 * Q16.16 format into integer.
993 	 * In order to accurately calculate the maximum packet size when
994 	 * the data interval is more than 1 (i.e. ep->datainterval > 0),
995 	 * multiply by the data interval prior to rounding. For instance,
996 	 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
997 	 * frames with a data interval of 1, but 11 (10.25) frames with a
998 	 * data interval of 2.
999 	 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
1000 	 * maximum datainterval value of 3, at USB full speed, higher for
1001 	 * USB high speed, noting that ep->freqmax is in units of
1002 	 * frames per packet in Q16.16 format.)
1003 	 */
1004 	maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
1005 			 (frame_bits >> 3);
1006 	if (tx_length_quirk)
1007 		maxsize += sizeof(__le32); /* Space for length descriptor */
1008 	/* but wMaxPacketSize might reduce this */
1009 	if (ep->maxpacksize && ep->maxpacksize < maxsize) {
1010 		/* whatever fits into a max. size packet */
1011 		unsigned int data_maxsize = maxsize = ep->maxpacksize;
1012 
1013 		if (tx_length_quirk)
1014 			/* Need to remove the length descriptor to calc freq */
1015 			data_maxsize -= sizeof(__le32);
1016 		ep->freqmax = (data_maxsize / (frame_bits >> 3))
1017 				<< (16 - ep->datainterval);
1018 	}
1019 
1020 	if (ep->fill_max)
1021 		ep->curpacksize = ep->maxpacksize;
1022 	else
1023 		ep->curpacksize = maxsize;
1024 
1025 	if (snd_usb_get_speed(chip->dev) != USB_SPEED_FULL) {
1026 		packs_per_ms = 8 >> ep->datainterval;
1027 		max_packs_per_urb = MAX_PACKS_HS;
1028 	} else {
1029 		packs_per_ms = 1;
1030 		max_packs_per_urb = MAX_PACKS;
1031 	}
1032 	if (ep->sync_source && !ep->implicit_fb_sync)
1033 		max_packs_per_urb = min(max_packs_per_urb,
1034 					1U << ep->sync_source->syncinterval);
1035 	max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
1036 
1037 	/*
1038 	 * Capture endpoints need to use small URBs because there's no way
1039 	 * to tell in advance where the next period will end, and we don't
1040 	 * want the next URB to complete much after the period ends.
1041 	 *
1042 	 * Playback endpoints with implicit sync much use the same parameters
1043 	 * as their corresponding capture endpoint.
1044 	 */
1045 	if (usb_pipein(ep->pipe) || ep->implicit_fb_sync) {
1046 
1047 		urb_packs = packs_per_ms;
1048 		/*
1049 		 * Wireless devices can poll at a max rate of once per 4ms.
1050 		 * For dataintervals less than 5, increase the packet count to
1051 		 * allow the host controller to use bursting to fill in the
1052 		 * gaps.
1053 		 */
1054 		if (snd_usb_get_speed(chip->dev) == USB_SPEED_WIRELESS) {
1055 			int interval = ep->datainterval;
1056 			while (interval < 5) {
1057 				urb_packs <<= 1;
1058 				++interval;
1059 			}
1060 		}
1061 		/* make capture URBs <= 1 ms and smaller than a period */
1062 		urb_packs = min(max_packs_per_urb, urb_packs);
1063 		while (urb_packs > 1 && urb_packs * maxsize >= ep->cur_period_bytes)
1064 			urb_packs >>= 1;
1065 		ep->nurbs = MAX_URBS;
1066 
1067 	/*
1068 	 * Playback endpoints without implicit sync are adjusted so that
1069 	 * a period fits as evenly as possible in the smallest number of
1070 	 * URBs.  The total number of URBs is adjusted to the size of the
1071 	 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
1072 	 */
1073 	} else {
1074 		/* determine how small a packet can be */
1075 		minsize = (ep->freqn >> (16 - ep->datainterval)) *
1076 				(frame_bits >> 3);
1077 		/* with sync from device, assume it can be 12% lower */
1078 		if (ep->sync_source)
1079 			minsize -= minsize >> 3;
1080 		minsize = max(minsize, 1u);
1081 
1082 		/* how many packets will contain an entire ALSA period? */
1083 		max_packs_per_period = DIV_ROUND_UP(ep->cur_period_bytes, minsize);
1084 
1085 		/* how many URBs will contain a period? */
1086 		urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
1087 				max_packs_per_urb);
1088 		/* how many packets are needed in each URB? */
1089 		urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
1090 
1091 		/* limit the number of frames in a single URB */
1092 		ep->max_urb_frames = DIV_ROUND_UP(ep->cur_period_frames,
1093 						  urbs_per_period);
1094 
1095 		/* try to use enough URBs to contain an entire ALSA buffer */
1096 		max_urbs = min((unsigned) MAX_URBS,
1097 				MAX_QUEUE * packs_per_ms / urb_packs);
1098 		ep->nurbs = min(max_urbs, urbs_per_period * ep->cur_buffer_periods);
1099 	}
1100 
1101 	/* allocate and initialize data urbs */
1102 	for (i = 0; i < ep->nurbs; i++) {
1103 		struct snd_urb_ctx *u = &ep->urb[i];
1104 		u->index = i;
1105 		u->ep = ep;
1106 		u->packets = urb_packs;
1107 		u->buffer_size = maxsize * u->packets;
1108 
1109 		if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
1110 			u->packets++; /* for transfer delimiter */
1111 		u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
1112 		if (!u->urb)
1113 			goto out_of_memory;
1114 
1115 		u->urb->transfer_buffer =
1116 			usb_alloc_coherent(chip->dev, u->buffer_size,
1117 					   GFP_KERNEL, &u->urb->transfer_dma);
1118 		if (!u->urb->transfer_buffer)
1119 			goto out_of_memory;
1120 		u->urb->pipe = ep->pipe;
1121 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1122 		u->urb->interval = 1 << ep->datainterval;
1123 		u->urb->context = u;
1124 		u->urb->complete = snd_complete_urb;
1125 		INIT_LIST_HEAD(&u->ready_list);
1126 	}
1127 
1128 	return 0;
1129 
1130 out_of_memory:
1131 	release_urbs(ep, false);
1132 	return -ENOMEM;
1133 }
1134 
1135 /*
1136  * configure a sync endpoint
1137  */
1138 static int sync_ep_set_params(struct snd_usb_endpoint *ep)
1139 {
1140 	struct snd_usb_audio *chip = ep->chip;
1141 	int i;
1142 
1143 	usb_audio_dbg(chip, "Setting params for sync EP 0x%x, pipe 0x%x\n",
1144 		      ep->ep_num, ep->pipe);
1145 
1146 	ep->syncbuf = usb_alloc_coherent(chip->dev, SYNC_URBS * 4,
1147 					 GFP_KERNEL, &ep->sync_dma);
1148 	if (!ep->syncbuf)
1149 		return -ENOMEM;
1150 
1151 	for (i = 0; i < SYNC_URBS; i++) {
1152 		struct snd_urb_ctx *u = &ep->urb[i];
1153 		u->index = i;
1154 		u->ep = ep;
1155 		u->packets = 1;
1156 		u->urb = usb_alloc_urb(1, GFP_KERNEL);
1157 		if (!u->urb)
1158 			goto out_of_memory;
1159 		u->urb->transfer_buffer = ep->syncbuf + i * 4;
1160 		u->urb->transfer_dma = ep->sync_dma + i * 4;
1161 		u->urb->transfer_buffer_length = 4;
1162 		u->urb->pipe = ep->pipe;
1163 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1164 		u->urb->number_of_packets = 1;
1165 		u->urb->interval = 1 << ep->syncinterval;
1166 		u->urb->context = u;
1167 		u->urb->complete = snd_complete_urb;
1168 	}
1169 
1170 	ep->nurbs = SYNC_URBS;
1171 
1172 	return 0;
1173 
1174 out_of_memory:
1175 	release_urbs(ep, false);
1176 	return -ENOMEM;
1177 }
1178 
1179 /*
1180  * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
1181  *
1182  * Determine the number of URBs to be used on this endpoint.
1183  * An endpoint must be configured before it can be started.
1184  * An endpoint that is already running can not be reconfigured.
1185  */
1186 static int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
1187 				       struct snd_usb_endpoint *ep)
1188 {
1189 	const struct audioformat *fmt = ep->cur_audiofmt;
1190 	int err;
1191 
1192 	/* release old buffers, if any */
1193 	err = release_urbs(ep, false);
1194 	if (err < 0)
1195 		return err;
1196 
1197 	ep->datainterval = fmt->datainterval;
1198 	ep->maxpacksize = fmt->maxpacksize;
1199 	ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
1200 
1201 	if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) {
1202 		ep->freqn = get_usb_full_speed_rate(ep->cur_rate);
1203 		ep->pps = 1000 >> ep->datainterval;
1204 	} else {
1205 		ep->freqn = get_usb_high_speed_rate(ep->cur_rate);
1206 		ep->pps = 8000 >> ep->datainterval;
1207 	}
1208 
1209 	ep->sample_rem = ep->cur_rate % ep->pps;
1210 	ep->packsize[0] = ep->cur_rate / ep->pps;
1211 	ep->packsize[1] = (ep->cur_rate + (ep->pps - 1)) / ep->pps;
1212 
1213 	/* calculate the frequency in 16.16 format */
1214 	ep->freqm = ep->freqn;
1215 	ep->freqshift = INT_MIN;
1216 
1217 	ep->phase = 0;
1218 
1219 	switch (ep->type) {
1220 	case  SND_USB_ENDPOINT_TYPE_DATA:
1221 		err = data_ep_set_params(ep);
1222 		break;
1223 	case  SND_USB_ENDPOINT_TYPE_SYNC:
1224 		err = sync_ep_set_params(ep);
1225 		break;
1226 	default:
1227 		err = -EINVAL;
1228 	}
1229 
1230 	usb_audio_dbg(chip, "Set up %d URBS, ret=%d\n", ep->nurbs, err);
1231 
1232 	if (err < 0)
1233 		return err;
1234 
1235 	/* some unit conversions in runtime */
1236 	ep->maxframesize = ep->maxpacksize / ep->cur_frame_bytes;
1237 	ep->curframesize = ep->curpacksize / ep->cur_frame_bytes;
1238 
1239 	return 0;
1240 }
1241 
1242 /*
1243  * snd_usb_endpoint_configure: Configure the endpoint
1244  *
1245  * This function sets up the EP to be fully usable state.
1246  * It's called either from hw_params or prepare callback.
1247  * The function checks need_setup flag, and perfoms nothing unless needed,
1248  * so it's safe to call this multiple times.
1249  *
1250  * This returns zero if unchanged, 1 if the configuration has changed,
1251  * or a negative error code.
1252  */
1253 int snd_usb_endpoint_configure(struct snd_usb_audio *chip,
1254 			       struct snd_usb_endpoint *ep)
1255 {
1256 	bool iface_first;
1257 	int err = 0;
1258 
1259 	mutex_lock(&chip->mutex);
1260 	if (WARN_ON(!ep->iface_ref))
1261 		goto unlock;
1262 	if (!ep->need_setup)
1263 		goto unlock;
1264 
1265 	/* If the interface has been already set up, just set EP parameters */
1266 	if (!ep->iface_ref->need_setup) {
1267 		/* sample rate setup of UAC1 is per endpoint, and we need
1268 		 * to update at each EP configuration
1269 		 */
1270 		if (ep->cur_audiofmt->protocol == UAC_VERSION_1) {
1271 			err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt,
1272 						       ep->cur_rate);
1273 			if (err < 0)
1274 				goto unlock;
1275 		}
1276 		err = snd_usb_endpoint_set_params(chip, ep);
1277 		if (err < 0)
1278 			goto unlock;
1279 		goto done;
1280 	}
1281 
1282 	/* Need to deselect altsetting at first */
1283 	endpoint_set_interface(chip, ep, false);
1284 
1285 	/* Some UAC1 devices (e.g. Yamaha THR10) need the host interface
1286 	 * to be set up before parameter setups
1287 	 */
1288 	iface_first = ep->cur_audiofmt->protocol == UAC_VERSION_1;
1289 	if (iface_first) {
1290 		err = endpoint_set_interface(chip, ep, true);
1291 		if (err < 0)
1292 			goto unlock;
1293 	}
1294 
1295 	err = snd_usb_init_pitch(chip, ep->cur_audiofmt);
1296 	if (err < 0)
1297 		goto unlock;
1298 
1299 	err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, ep->cur_rate);
1300 	if (err < 0)
1301 		goto unlock;
1302 
1303 	err = snd_usb_endpoint_set_params(chip, ep);
1304 	if (err < 0)
1305 		goto unlock;
1306 
1307 	err = snd_usb_select_mode_quirk(chip, ep->cur_audiofmt);
1308 	if (err < 0)
1309 		goto unlock;
1310 
1311 	/* for UAC2/3, enable the interface altset here at last */
1312 	if (!iface_first) {
1313 		err = endpoint_set_interface(chip, ep, true);
1314 		if (err < 0)
1315 			goto unlock;
1316 	}
1317 
1318 	ep->iface_ref->need_setup = false;
1319 
1320  done:
1321 	ep->need_setup = false;
1322 	err = 1;
1323 
1324 unlock:
1325 	mutex_unlock(&chip->mutex);
1326 	return err;
1327 }
1328 
1329 /**
1330  * snd_usb_endpoint_start: start an snd_usb_endpoint
1331  *
1332  * @ep: the endpoint to start
1333  *
1334  * A call to this function will increment the running count of the endpoint.
1335  * In case it is not already running, the URBs for this endpoint will be
1336  * submitted. Otherwise, this function does nothing.
1337  *
1338  * Must be balanced to calls of snd_usb_endpoint_stop().
1339  *
1340  * Returns an error if the URB submission failed, 0 in all other cases.
1341  */
1342 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
1343 {
1344 	int err;
1345 	unsigned int i;
1346 
1347 	if (atomic_read(&ep->chip->shutdown))
1348 		return -EBADFD;
1349 
1350 	if (ep->sync_source)
1351 		WRITE_ONCE(ep->sync_source->sync_sink, ep);
1352 
1353 	usb_audio_dbg(ep->chip, "Starting %s EP 0x%x (running %d)\n",
1354 		      ep_type_name(ep->type), ep->ep_num,
1355 		      atomic_read(&ep->running));
1356 
1357 	/* already running? */
1358 	if (atomic_inc_return(&ep->running) != 1)
1359 		return 0;
1360 
1361 	ep->active_mask = 0;
1362 	ep->unlink_mask = 0;
1363 	ep->phase = 0;
1364 	ep->sample_accum = 0;
1365 
1366 	snd_usb_endpoint_start_quirk(ep);
1367 
1368 	/*
1369 	 * If this endpoint has a data endpoint as implicit feedback source,
1370 	 * don't start the urbs here. Instead, mark them all as available,
1371 	 * wait for the record urbs to return and queue the playback urbs
1372 	 * from that context.
1373 	 */
1374 
1375 	if (!ep_state_update(ep, EP_STATE_STOPPED, EP_STATE_RUNNING))
1376 		goto __error;
1377 
1378 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1379 	    !ep->chip->playback_first) {
1380 		for (i = 0; i < ep->nurbs; i++) {
1381 			struct snd_urb_ctx *ctx = ep->urb + i;
1382 			list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
1383 		}
1384 
1385 		usb_audio_dbg(ep->chip, "No URB submission due to implicit fb sync\n");
1386 		return 0;
1387 	}
1388 
1389 	for (i = 0; i < ep->nurbs; i++) {
1390 		struct urb *urb = ep->urb[i].urb;
1391 
1392 		if (snd_BUG_ON(!urb))
1393 			goto __error;
1394 
1395 		if (usb_pipeout(ep->pipe)) {
1396 			prepare_outbound_urb(ep, urb->context);
1397 		} else {
1398 			prepare_inbound_urb(ep, urb->context);
1399 		}
1400 
1401 		err = usb_submit_urb(urb, GFP_ATOMIC);
1402 		if (err < 0) {
1403 			usb_audio_err(ep->chip,
1404 				"cannot submit urb %d, error %d: %s\n",
1405 				i, err, usb_error_string(err));
1406 			goto __error;
1407 		}
1408 		set_bit(i, &ep->active_mask);
1409 	}
1410 
1411 	usb_audio_dbg(ep->chip, "%d URBs submitted for EP 0x%x\n",
1412 		      ep->nurbs, ep->ep_num);
1413 	return 0;
1414 
1415 __error:
1416 	snd_usb_endpoint_stop(ep);
1417 	return -EPIPE;
1418 }
1419 
1420 /**
1421  * snd_usb_endpoint_stop: stop an snd_usb_endpoint
1422  *
1423  * @ep: the endpoint to stop (may be NULL)
1424  *
1425  * A call to this function will decrement the running count of the endpoint.
1426  * In case the last user has requested the endpoint stop, the URBs will
1427  * actually be deactivated.
1428  *
1429  * Must be balanced to calls of snd_usb_endpoint_start().
1430  *
1431  * The caller needs to synchronize the pending stop operation via
1432  * snd_usb_endpoint_sync_pending_stop().
1433  */
1434 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep)
1435 {
1436 	if (!ep)
1437 		return;
1438 
1439 	usb_audio_dbg(ep->chip, "Stopping %s EP 0x%x (running %d)\n",
1440 		      ep_type_name(ep->type), ep->ep_num,
1441 		      atomic_read(&ep->running));
1442 
1443 	if (snd_BUG_ON(!atomic_read(&ep->running)))
1444 		return;
1445 
1446 	if (!atomic_dec_return(&ep->running)) {
1447 		if (ep->sync_source)
1448 			WRITE_ONCE(ep->sync_source->sync_sink, NULL);
1449 		stop_urbs(ep, false);
1450 	}
1451 }
1452 
1453 /**
1454  * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1455  *
1456  * @ep: the endpoint to release
1457  *
1458  * This function does not care for the endpoint's running count but will tear
1459  * down all the streaming URBs immediately.
1460  */
1461 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1462 {
1463 	release_urbs(ep, true);
1464 }
1465 
1466 /**
1467  * snd_usb_endpoint_free_all: Free the resources of an snd_usb_endpoint
1468  * @chip: The chip
1469  *
1470  * This free all endpoints and those resources
1471  */
1472 void snd_usb_endpoint_free_all(struct snd_usb_audio *chip)
1473 {
1474 	struct snd_usb_endpoint *ep, *en;
1475 	struct snd_usb_iface_ref *ip, *in;
1476 
1477 	list_for_each_entry_safe(ep, en, &chip->ep_list, list)
1478 		kfree(ep);
1479 
1480 	list_for_each_entry_safe(ip, in, &chip->iface_ref_list, list)
1481 		kfree(ip);
1482 }
1483 
1484 /*
1485  * snd_usb_handle_sync_urb: parse an USB sync packet
1486  *
1487  * @ep: the endpoint to handle the packet
1488  * @sender: the sending endpoint
1489  * @urb: the received packet
1490  *
1491  * This function is called from the context of an endpoint that received
1492  * the packet and is used to let another endpoint object handle the payload.
1493  */
1494 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1495 				    struct snd_usb_endpoint *sender,
1496 				    const struct urb *urb)
1497 {
1498 	int shift;
1499 	unsigned int f;
1500 	unsigned long flags;
1501 
1502 	snd_BUG_ON(ep == sender);
1503 
1504 	/*
1505 	 * In case the endpoint is operating in implicit feedback mode, prepare
1506 	 * a new outbound URB that has the same layout as the received packet
1507 	 * and add it to the list of pending urbs. queue_pending_output_urbs()
1508 	 * will take care of them later.
1509 	 */
1510 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1511 	    atomic_read(&ep->running)) {
1512 
1513 		/* implicit feedback case */
1514 		int i, bytes = 0;
1515 		struct snd_urb_ctx *in_ctx;
1516 		struct snd_usb_packet_info *out_packet;
1517 
1518 		in_ctx = urb->context;
1519 
1520 		/* Count overall packet size */
1521 		for (i = 0; i < in_ctx->packets; i++)
1522 			if (urb->iso_frame_desc[i].status == 0)
1523 				bytes += urb->iso_frame_desc[i].actual_length;
1524 
1525 		/*
1526 		 * skip empty packets. At least M-Audio's Fast Track Ultra stops
1527 		 * streaming once it received a 0-byte OUT URB
1528 		 */
1529 		if (bytes == 0)
1530 			return;
1531 
1532 		spin_lock_irqsave(&ep->lock, flags);
1533 		if (ep->next_packet_queued >= ARRAY_SIZE(ep->next_packet)) {
1534 			spin_unlock_irqrestore(&ep->lock, flags);
1535 			usb_audio_err(ep->chip,
1536 				      "next package FIFO overflow EP 0x%x\n",
1537 				      ep->ep_num);
1538 			notify_xrun(ep);
1539 			return;
1540 		}
1541 
1542 		out_packet = next_packet_fifo_enqueue(ep);
1543 
1544 		/*
1545 		 * Iterate through the inbound packet and prepare the lengths
1546 		 * for the output packet. The OUT packet we are about to send
1547 		 * will have the same amount of payload bytes per stride as the
1548 		 * IN packet we just received. Since the actual size is scaled
1549 		 * by the stride, use the sender stride to calculate the length
1550 		 * in case the number of channels differ between the implicitly
1551 		 * fed-back endpoint and the synchronizing endpoint.
1552 		 */
1553 
1554 		out_packet->packets = in_ctx->packets;
1555 		for (i = 0; i < in_ctx->packets; i++) {
1556 			if (urb->iso_frame_desc[i].status == 0)
1557 				out_packet->packet_size[i] =
1558 					urb->iso_frame_desc[i].actual_length / sender->stride;
1559 			else
1560 				out_packet->packet_size[i] = 0;
1561 		}
1562 
1563 		spin_unlock_irqrestore(&ep->lock, flags);
1564 		queue_pending_output_urbs(ep);
1565 
1566 		return;
1567 	}
1568 
1569 	/*
1570 	 * process after playback sync complete
1571 	 *
1572 	 * Full speed devices report feedback values in 10.14 format as samples
1573 	 * per frame, high speed devices in 16.16 format as samples per
1574 	 * microframe.
1575 	 *
1576 	 * Because the Audio Class 1 spec was written before USB 2.0, many high
1577 	 * speed devices use a wrong interpretation, some others use an
1578 	 * entirely different format.
1579 	 *
1580 	 * Therefore, we cannot predict what format any particular device uses
1581 	 * and must detect it automatically.
1582 	 */
1583 
1584 	if (urb->iso_frame_desc[0].status != 0 ||
1585 	    urb->iso_frame_desc[0].actual_length < 3)
1586 		return;
1587 
1588 	f = le32_to_cpup(urb->transfer_buffer);
1589 	if (urb->iso_frame_desc[0].actual_length == 3)
1590 		f &= 0x00ffffff;
1591 	else
1592 		f &= 0x0fffffff;
1593 
1594 	if (f == 0)
1595 		return;
1596 
1597 	if (unlikely(sender->tenor_fb_quirk)) {
1598 		/*
1599 		 * Devices based on Tenor 8802 chipsets (TEAC UD-H01
1600 		 * and others) sometimes change the feedback value
1601 		 * by +/- 0x1.0000.
1602 		 */
1603 		if (f < ep->freqn - 0x8000)
1604 			f += 0xf000;
1605 		else if (f > ep->freqn + 0x8000)
1606 			f -= 0xf000;
1607 	} else if (unlikely(ep->freqshift == INT_MIN)) {
1608 		/*
1609 		 * The first time we see a feedback value, determine its format
1610 		 * by shifting it left or right until it matches the nominal
1611 		 * frequency value.  This assumes that the feedback does not
1612 		 * differ from the nominal value more than +50% or -25%.
1613 		 */
1614 		shift = 0;
1615 		while (f < ep->freqn - ep->freqn / 4) {
1616 			f <<= 1;
1617 			shift++;
1618 		}
1619 		while (f > ep->freqn + ep->freqn / 2) {
1620 			f >>= 1;
1621 			shift--;
1622 		}
1623 		ep->freqshift = shift;
1624 	} else if (ep->freqshift >= 0)
1625 		f <<= ep->freqshift;
1626 	else
1627 		f >>= -ep->freqshift;
1628 
1629 	if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1630 		/*
1631 		 * If the frequency looks valid, set it.
1632 		 * This value is referred to in prepare_playback_urb().
1633 		 */
1634 		spin_lock_irqsave(&ep->lock, flags);
1635 		ep->freqm = f;
1636 		spin_unlock_irqrestore(&ep->lock, flags);
1637 	} else {
1638 		/*
1639 		 * Out of range; maybe the shift value is wrong.
1640 		 * Reset it so that we autodetect again the next time.
1641 		 */
1642 		ep->freqshift = INT_MIN;
1643 	}
1644 }
1645 
1646