xref: /linux/sound/usb/endpoint.c (revision 87807f77a03d0271211b75f84b2a8b88f4e8e5d4)
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 	int altset;
36 	struct list_head list;
37 };
38 
39 /* clock refcounting */
40 struct snd_usb_clock_ref {
41 	unsigned char clock;
42 	atomic_t locked;
43 	int opened;
44 	int rate;
45 	bool need_setup;
46 	struct list_head list;
47 };
48 
49 /*
50  * snd_usb_endpoint is a model that abstracts everything related to an
51  * USB endpoint and its streaming.
52  *
53  * There are functions to activate and deactivate the streaming URBs and
54  * optional callbacks to let the pcm logic handle the actual content of the
55  * packets for playback and record. Thus, the bus streaming and the audio
56  * handlers are fully decoupled.
57  *
58  * There are two different types of endpoints in audio applications.
59  *
60  * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
61  * inbound and outbound traffic.
62  *
63  * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
64  * expect the payload to carry Q10.14 / Q16.16 formatted sync information
65  * (3 or 4 bytes).
66  *
67  * Each endpoint has to be configured prior to being used by calling
68  * snd_usb_endpoint_set_params().
69  *
70  * The model incorporates a reference counting, so that multiple users
71  * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
72  * only the first user will effectively start the URBs, and only the last
73  * one to stop it will tear the URBs down again.
74  */
75 
76 /*
77  * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
78  * this will overflow at approx 524 kHz
79  */
80 static inline unsigned get_usb_full_speed_rate(unsigned int rate)
81 {
82 	return ((rate << 13) + 62) / 125;
83 }
84 
85 /*
86  * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
87  * this will overflow at approx 4 MHz
88  */
89 static inline unsigned get_usb_high_speed_rate(unsigned int rate)
90 {
91 	return ((rate << 10) + 62) / 125;
92 }
93 
94 /*
95  * release a urb data
96  */
97 static void release_urb_ctx(struct snd_urb_ctx *u)
98 {
99 	if (u->urb && u->buffer_size)
100 		usb_free_coherent(u->ep->chip->dev, u->buffer_size,
101 				  u->urb->transfer_buffer,
102 				  u->urb->transfer_dma);
103 	usb_free_urb(u->urb);
104 	u->urb = NULL;
105 	u->buffer_size = 0;
106 }
107 
108 static const char *usb_error_string(int err)
109 {
110 	switch (err) {
111 	case -ENODEV:
112 		return "no device";
113 	case -ENOENT:
114 		return "endpoint not enabled";
115 	case -EPIPE:
116 		return "endpoint stalled";
117 	case -ENOSPC:
118 		return "not enough bandwidth";
119 	case -ESHUTDOWN:
120 		return "device disabled";
121 	case -EHOSTUNREACH:
122 		return "device suspended";
123 	case -EINVAL:
124 	case -EAGAIN:
125 	case -EFBIG:
126 	case -EMSGSIZE:
127 		return "internal error";
128 	default:
129 		return "unknown error";
130 	}
131 }
132 
133 static inline bool ep_state_running(struct snd_usb_endpoint *ep)
134 {
135 	return atomic_read(&ep->state) == EP_STATE_RUNNING;
136 }
137 
138 static inline bool ep_state_update(struct snd_usb_endpoint *ep, int old, int new)
139 {
140 	return atomic_try_cmpxchg(&ep->state, &old, new);
141 }
142 
143 /**
144  * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
145  *
146  * @ep: The snd_usb_endpoint
147  *
148  * Determine whether an endpoint is driven by an implicit feedback
149  * data endpoint source.
150  */
151 int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
152 {
153 	return  ep->implicit_fb_sync && usb_pipeout(ep->pipe);
154 }
155 
156 /*
157  * Return the number of samples to be sent in the next packet
158  * for streaming based on information derived from sync endpoints
159  *
160  * This won't be used for implicit feedback which takes the packet size
161  * returned from the sync source
162  */
163 static int slave_next_packet_size(struct snd_usb_endpoint *ep,
164 				  unsigned int avail)
165 {
166 	unsigned long flags;
167 	unsigned int phase;
168 	int ret;
169 
170 	if (ep->fill_max)
171 		return ep->maxframesize;
172 
173 	spin_lock_irqsave(&ep->lock, flags);
174 	phase = (ep->phase & 0xffff) + (ep->freqm << ep->datainterval);
175 	ret = min(phase >> 16, ep->maxframesize);
176 	if (avail && ret >= avail)
177 		ret = -EAGAIN;
178 	else
179 		ep->phase = phase;
180 	spin_unlock_irqrestore(&ep->lock, flags);
181 
182 	return ret;
183 }
184 
185 /*
186  * Return the number of samples to be sent in the next packet
187  * for adaptive and synchronous endpoints
188  */
189 static int next_packet_size(struct snd_usb_endpoint *ep, unsigned int avail)
190 {
191 	unsigned int sample_accum;
192 	int ret;
193 
194 	if (ep->fill_max)
195 		return ep->maxframesize;
196 
197 	sample_accum = ep->sample_accum + ep->sample_rem;
198 	if (sample_accum >= ep->pps) {
199 		sample_accum -= ep->pps;
200 		ret = ep->packsize[1];
201 	} else {
202 		ret = ep->packsize[0];
203 	}
204 	if (avail && ret >= avail)
205 		ret = -EAGAIN;
206 	else
207 		ep->sample_accum = sample_accum;
208 
209 	return ret;
210 }
211 
212 /*
213  * snd_usb_endpoint_next_packet_size: Return the number of samples to be sent
214  * in the next packet
215  *
216  * If the size is equal or exceeds @avail, don't proceed but return -EAGAIN
217  * Exception: @avail = 0 for skipping the check.
218  */
219 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep,
220 				      struct snd_urb_ctx *ctx, int idx,
221 				      unsigned int avail)
222 {
223 	unsigned int packet;
224 
225 	packet = ctx->packet_size[idx];
226 	if (packet) {
227 		if (avail && packet >= avail)
228 			return -EAGAIN;
229 		return packet;
230 	}
231 
232 	if (ep->sync_source)
233 		return slave_next_packet_size(ep, avail);
234 	else
235 		return next_packet_size(ep, avail);
236 }
237 
238 static void call_retire_callback(struct snd_usb_endpoint *ep,
239 				 struct urb *urb)
240 {
241 	struct snd_usb_substream *data_subs;
242 
243 	data_subs = READ_ONCE(ep->data_subs);
244 	if (data_subs && ep->retire_data_urb)
245 		ep->retire_data_urb(data_subs, urb);
246 }
247 
248 static void retire_outbound_urb(struct snd_usb_endpoint *ep,
249 				struct snd_urb_ctx *urb_ctx)
250 {
251 	call_retire_callback(ep, urb_ctx->urb);
252 }
253 
254 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
255 				    struct snd_usb_endpoint *sender,
256 				    const struct urb *urb);
257 
258 static void retire_inbound_urb(struct snd_usb_endpoint *ep,
259 			       struct snd_urb_ctx *urb_ctx)
260 {
261 	struct urb *urb = urb_ctx->urb;
262 	struct snd_usb_endpoint *sync_sink;
263 
264 	if (unlikely(ep->skip_packets > 0)) {
265 		ep->skip_packets--;
266 		return;
267 	}
268 
269 	sync_sink = READ_ONCE(ep->sync_sink);
270 	if (sync_sink)
271 		snd_usb_handle_sync_urb(sync_sink, ep, urb);
272 
273 	call_retire_callback(ep, urb);
274 }
275 
276 static inline bool has_tx_length_quirk(struct snd_usb_audio *chip)
277 {
278 	return chip->quirk_flags & QUIRK_FLAG_TX_LENGTH;
279 }
280 
281 static void prepare_silent_urb(struct snd_usb_endpoint *ep,
282 			       struct snd_urb_ctx *ctx)
283 {
284 	struct urb *urb = ctx->urb;
285 	unsigned int offs = 0;
286 	unsigned int extra = 0;
287 	__le32 packet_length;
288 	int i;
289 
290 	/* For tx_length_quirk, put packet length at start of packet */
291 	if (has_tx_length_quirk(ep->chip))
292 		extra = sizeof(packet_length);
293 
294 	for (i = 0; i < ctx->packets; ++i) {
295 		unsigned int offset;
296 		unsigned int length;
297 		int counts;
298 
299 		counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, 0);
300 		length = counts * ep->stride; /* number of silent bytes */
301 		offset = offs * ep->stride + extra * i;
302 		urb->iso_frame_desc[i].offset = offset;
303 		urb->iso_frame_desc[i].length = length + extra;
304 		if (extra) {
305 			packet_length = cpu_to_le32(length);
306 			memcpy(urb->transfer_buffer + offset,
307 			       &packet_length, sizeof(packet_length));
308 		}
309 		memset(urb->transfer_buffer + offset + extra,
310 		       ep->silence_value, length);
311 		offs += counts;
312 	}
313 
314 	urb->number_of_packets = ctx->packets;
315 	urb->transfer_buffer_length = offs * ep->stride + ctx->packets * extra;
316 	ctx->queued = 0;
317 }
318 
319 /*
320  * Prepare a PLAYBACK urb for submission to the bus.
321  */
322 static int prepare_outbound_urb(struct snd_usb_endpoint *ep,
323 				struct snd_urb_ctx *ctx,
324 				bool in_stream_lock)
325 {
326 	struct urb *urb = ctx->urb;
327 	unsigned char *cp = urb->transfer_buffer;
328 	struct snd_usb_substream *data_subs;
329 
330 	urb->dev = ep->chip->dev; /* we need to set this at each time */
331 
332 	switch (ep->type) {
333 	case SND_USB_ENDPOINT_TYPE_DATA:
334 		data_subs = READ_ONCE(ep->data_subs);
335 		if (data_subs && ep->prepare_data_urb)
336 			return ep->prepare_data_urb(data_subs, urb, in_stream_lock);
337 		/* no data provider, so send silence */
338 		prepare_silent_urb(ep, ctx);
339 		break;
340 
341 	case SND_USB_ENDPOINT_TYPE_SYNC:
342 		if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
343 			/*
344 			 * fill the length and offset of each urb descriptor.
345 			 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
346 			 */
347 			urb->iso_frame_desc[0].length = 4;
348 			urb->iso_frame_desc[0].offset = 0;
349 			cp[0] = ep->freqn;
350 			cp[1] = ep->freqn >> 8;
351 			cp[2] = ep->freqn >> 16;
352 			cp[3] = ep->freqn >> 24;
353 		} else {
354 			/*
355 			 * fill the length and offset of each urb descriptor.
356 			 * the fixed 10.14 frequency is passed through the pipe.
357 			 */
358 			urb->iso_frame_desc[0].length = 3;
359 			urb->iso_frame_desc[0].offset = 0;
360 			cp[0] = ep->freqn >> 2;
361 			cp[1] = ep->freqn >> 10;
362 			cp[2] = ep->freqn >> 18;
363 		}
364 
365 		break;
366 	}
367 	return 0;
368 }
369 
370 /*
371  * Prepare a CAPTURE or SYNC urb for submission to the bus.
372  */
373 static int prepare_inbound_urb(struct snd_usb_endpoint *ep,
374 			       struct snd_urb_ctx *urb_ctx)
375 {
376 	int i, offs;
377 	struct urb *urb = urb_ctx->urb;
378 
379 	urb->dev = ep->chip->dev; /* we need to set this at each time */
380 
381 	switch (ep->type) {
382 	case SND_USB_ENDPOINT_TYPE_DATA:
383 		offs = 0;
384 		for (i = 0; i < urb_ctx->packets; i++) {
385 			urb->iso_frame_desc[i].offset = offs;
386 			urb->iso_frame_desc[i].length = ep->curpacksize;
387 			offs += ep->curpacksize;
388 		}
389 
390 		urb->transfer_buffer_length = offs;
391 		urb->number_of_packets = urb_ctx->packets;
392 		break;
393 
394 	case SND_USB_ENDPOINT_TYPE_SYNC:
395 		urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
396 		urb->iso_frame_desc[0].offset = 0;
397 		break;
398 	}
399 	return 0;
400 }
401 
402 /* notify an error as XRUN to the assigned PCM data substream */
403 static void notify_xrun(struct snd_usb_endpoint *ep)
404 {
405 	struct snd_usb_substream *data_subs;
406 
407 	data_subs = READ_ONCE(ep->data_subs);
408 	if (data_subs && data_subs->pcm_substream)
409 		snd_pcm_stop_xrun(data_subs->pcm_substream);
410 }
411 
412 static struct snd_usb_packet_info *
413 next_packet_fifo_enqueue(struct snd_usb_endpoint *ep)
414 {
415 	struct snd_usb_packet_info *p;
416 
417 	p = ep->next_packet + (ep->next_packet_head + ep->next_packet_queued) %
418 		ARRAY_SIZE(ep->next_packet);
419 	ep->next_packet_queued++;
420 	return p;
421 }
422 
423 static struct snd_usb_packet_info *
424 next_packet_fifo_dequeue(struct snd_usb_endpoint *ep)
425 {
426 	struct snd_usb_packet_info *p;
427 
428 	p = ep->next_packet + ep->next_packet_head;
429 	ep->next_packet_head++;
430 	ep->next_packet_head %= ARRAY_SIZE(ep->next_packet);
431 	ep->next_packet_queued--;
432 	return p;
433 }
434 
435 static void push_back_to_ready_list(struct snd_usb_endpoint *ep,
436 				    struct snd_urb_ctx *ctx)
437 {
438 	unsigned long flags;
439 
440 	spin_lock_irqsave(&ep->lock, flags);
441 	list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
442 	spin_unlock_irqrestore(&ep->lock, flags);
443 }
444 
445 /*
446  * Send output urbs that have been prepared previously. URBs are dequeued
447  * from ep->ready_playback_urbs and in case there aren't any available
448  * or there are no packets that have been prepared, this function does
449  * nothing.
450  *
451  * The reason why the functionality of sending and preparing URBs is separated
452  * is that host controllers don't guarantee the order in which they return
453  * inbound and outbound packets to their submitters.
454  *
455  * This function is used both for implicit feedback endpoints and in low-
456  * latency playback mode.
457  */
458 int snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep,
459 				      bool in_stream_lock)
460 {
461 	bool implicit_fb = snd_usb_endpoint_implicit_feedback_sink(ep);
462 
463 	while (ep_state_running(ep)) {
464 
465 		unsigned long flags;
466 		struct snd_usb_packet_info *packet;
467 		struct snd_urb_ctx *ctx = NULL;
468 		int err, i;
469 
470 		spin_lock_irqsave(&ep->lock, flags);
471 		if ((!implicit_fb || ep->next_packet_queued > 0) &&
472 		    !list_empty(&ep->ready_playback_urbs)) {
473 			/* take URB out of FIFO */
474 			ctx = list_first_entry(&ep->ready_playback_urbs,
475 					       struct snd_urb_ctx, ready_list);
476 			list_del_init(&ctx->ready_list);
477 			if (implicit_fb)
478 				packet = next_packet_fifo_dequeue(ep);
479 		}
480 		spin_unlock_irqrestore(&ep->lock, flags);
481 
482 		if (ctx == NULL)
483 			break;
484 
485 		/* copy over the length information */
486 		if (implicit_fb) {
487 			for (i = 0; i < packet->packets; i++)
488 				ctx->packet_size[i] = packet->packet_size[i];
489 		}
490 
491 		/* call the data handler to fill in playback data */
492 		err = prepare_outbound_urb(ep, ctx, in_stream_lock);
493 		/* can be stopped during prepare callback */
494 		if (unlikely(!ep_state_running(ep)))
495 			break;
496 		if (err < 0) {
497 			/* push back to ready list again for -EAGAIN */
498 			if (err == -EAGAIN) {
499 				push_back_to_ready_list(ep, ctx);
500 				break;
501 			}
502 
503 			if (!in_stream_lock)
504 				notify_xrun(ep);
505 			return -EPIPE;
506 		}
507 
508 		err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
509 		if (err < 0) {
510 			usb_audio_err(ep->chip,
511 				      "Unable to submit urb #%d: %d at %s\n",
512 				      ctx->index, err, __func__);
513 			if (!in_stream_lock)
514 				notify_xrun(ep);
515 			return -EPIPE;
516 		}
517 
518 		set_bit(ctx->index, &ep->active_mask);
519 		atomic_inc(&ep->submitted_urbs);
520 	}
521 
522 	return 0;
523 }
524 
525 /*
526  * complete callback for urbs
527  */
528 static void snd_complete_urb(struct urb *urb)
529 {
530 	struct snd_urb_ctx *ctx = urb->context;
531 	struct snd_usb_endpoint *ep = ctx->ep;
532 	int err;
533 
534 	if (unlikely(urb->status == -ENOENT ||		/* unlinked */
535 		     urb->status == -ENODEV ||		/* device removed */
536 		     urb->status == -ECONNRESET ||	/* unlinked */
537 		     urb->status == -ESHUTDOWN))	/* device disabled */
538 		goto exit_clear;
539 	/* device disconnected */
540 	if (unlikely(atomic_read(&ep->chip->shutdown)))
541 		goto exit_clear;
542 
543 	if (unlikely(!ep_state_running(ep)))
544 		goto exit_clear;
545 
546 	if (usb_pipeout(ep->pipe)) {
547 		retire_outbound_urb(ep, ctx);
548 		/* can be stopped during retire callback */
549 		if (unlikely(!ep_state_running(ep)))
550 			goto exit_clear;
551 
552 		/* in low-latency and implicit-feedback modes, push back the
553 		 * URB to ready list at first, then process as much as possible
554 		 */
555 		if (ep->lowlatency_playback ||
556 		     snd_usb_endpoint_implicit_feedback_sink(ep)) {
557 			push_back_to_ready_list(ep, ctx);
558 			clear_bit(ctx->index, &ep->active_mask);
559 			snd_usb_queue_pending_output_urbs(ep, false);
560 			atomic_dec(&ep->submitted_urbs); /* decrement at last */
561 			return;
562 		}
563 
564 		/* in non-lowlatency mode, no error handling for prepare */
565 		prepare_outbound_urb(ep, ctx, false);
566 		/* can be stopped during prepare callback */
567 		if (unlikely(!ep_state_running(ep)))
568 			goto exit_clear;
569 	} else {
570 		retire_inbound_urb(ep, ctx);
571 		/* can be stopped during retire callback */
572 		if (unlikely(!ep_state_running(ep)))
573 			goto exit_clear;
574 
575 		prepare_inbound_urb(ep, ctx);
576 	}
577 
578 	err = usb_submit_urb(urb, GFP_ATOMIC);
579 	if (err == 0)
580 		return;
581 
582 	usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
583 	notify_xrun(ep);
584 
585 exit_clear:
586 	clear_bit(ctx->index, &ep->active_mask);
587 	atomic_dec(&ep->submitted_urbs);
588 }
589 
590 /*
591  * Find or create a refcount object for the given interface
592  *
593  * The objects are released altogether in snd_usb_endpoint_free_all()
594  */
595 static struct snd_usb_iface_ref *
596 iface_ref_find(struct snd_usb_audio *chip, int iface)
597 {
598 	struct snd_usb_iface_ref *ip;
599 
600 	list_for_each_entry(ip, &chip->iface_ref_list, list)
601 		if (ip->iface == iface)
602 			return ip;
603 
604 	ip = kzalloc(sizeof(*ip), GFP_KERNEL);
605 	if (!ip)
606 		return NULL;
607 	ip->iface = iface;
608 	list_add_tail(&ip->list, &chip->iface_ref_list);
609 	return ip;
610 }
611 
612 /* Similarly, a refcount object for clock */
613 static struct snd_usb_clock_ref *
614 clock_ref_find(struct snd_usb_audio *chip, int clock)
615 {
616 	struct snd_usb_clock_ref *ref;
617 
618 	list_for_each_entry(ref, &chip->clock_ref_list, list)
619 		if (ref->clock == clock)
620 			return ref;
621 
622 	ref = kzalloc(sizeof(*ref), GFP_KERNEL);
623 	if (!ref)
624 		return NULL;
625 	ref->clock = clock;
626 	atomic_set(&ref->locked, 0);
627 	list_add_tail(&ref->list, &chip->clock_ref_list);
628 	return ref;
629 }
630 
631 /*
632  * Get the existing endpoint object corresponding EP
633  * Returns NULL if not present.
634  */
635 struct snd_usb_endpoint *
636 snd_usb_get_endpoint(struct snd_usb_audio *chip, int ep_num)
637 {
638 	struct snd_usb_endpoint *ep;
639 
640 	list_for_each_entry(ep, &chip->ep_list, list) {
641 		if (ep->ep_num == ep_num)
642 			return ep;
643 	}
644 
645 	return NULL;
646 }
647 
648 #define ep_type_name(type) \
649 	(type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync")
650 
651 /**
652  * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
653  *
654  * @chip: The chip
655  * @ep_num: The number of the endpoint to use
656  * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
657  *
658  * If the requested endpoint has not been added to the given chip before,
659  * a new instance is created.
660  *
661  * Returns zero on success or a negative error code.
662  *
663  * New endpoints will be added to chip->ep_list and freed by
664  * calling snd_usb_endpoint_free_all().
665  *
666  * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
667  * bNumEndpoints > 1 beforehand.
668  */
669 int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type)
670 {
671 	struct snd_usb_endpoint *ep;
672 	bool is_playback;
673 
674 	ep = snd_usb_get_endpoint(chip, ep_num);
675 	if (ep)
676 		return 0;
677 
678 	usb_audio_dbg(chip, "Creating new %s endpoint #%x\n",
679 		      ep_type_name(type),
680 		      ep_num);
681 	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
682 	if (!ep)
683 		return -ENOMEM;
684 
685 	ep->chip = chip;
686 	spin_lock_init(&ep->lock);
687 	ep->type = type;
688 	ep->ep_num = ep_num;
689 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
690 	atomic_set(&ep->submitted_urbs, 0);
691 
692 	is_playback = ((ep_num & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT);
693 	ep_num &= USB_ENDPOINT_NUMBER_MASK;
694 	if (is_playback)
695 		ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
696 	else
697 		ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
698 
699 	list_add_tail(&ep->list, &chip->ep_list);
700 	return 0;
701 }
702 
703 /* Set up syncinterval and maxsyncsize for a sync EP */
704 static void endpoint_set_syncinterval(struct snd_usb_audio *chip,
705 				      struct snd_usb_endpoint *ep)
706 {
707 	struct usb_host_interface *alts;
708 	struct usb_endpoint_descriptor *desc;
709 
710 	alts = snd_usb_get_host_interface(chip, ep->iface, ep->altsetting);
711 	if (!alts)
712 		return;
713 
714 	desc = get_endpoint(alts, ep->ep_idx);
715 	if (desc->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
716 	    desc->bRefresh >= 1 && desc->bRefresh <= 9)
717 		ep->syncinterval = desc->bRefresh;
718 	else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
719 		ep->syncinterval = 1;
720 	else if (desc->bInterval >= 1 && desc->bInterval <= 16)
721 		ep->syncinterval = desc->bInterval - 1;
722 	else
723 		ep->syncinterval = 3;
724 
725 	ep->syncmaxsize = le16_to_cpu(desc->wMaxPacketSize);
726 }
727 
728 static bool endpoint_compatible(struct snd_usb_endpoint *ep,
729 				const struct audioformat *fp,
730 				const struct snd_pcm_hw_params *params)
731 {
732 	if (!ep->opened)
733 		return false;
734 	if (ep->cur_audiofmt != fp)
735 		return false;
736 	if (ep->cur_rate != params_rate(params) ||
737 	    ep->cur_format != params_format(params) ||
738 	    ep->cur_period_frames != params_period_size(params) ||
739 	    ep->cur_buffer_periods != params_periods(params))
740 		return false;
741 	return true;
742 }
743 
744 /*
745  * Check whether the given fp and hw params are compatible with the current
746  * setup of the target EP for implicit feedback sync
747  */
748 bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip,
749 				 struct snd_usb_endpoint *ep,
750 				 const struct audioformat *fp,
751 				 const struct snd_pcm_hw_params *params)
752 {
753 	bool ret;
754 
755 	mutex_lock(&chip->mutex);
756 	ret = endpoint_compatible(ep, fp, params);
757 	mutex_unlock(&chip->mutex);
758 	return ret;
759 }
760 
761 /*
762  * snd_usb_endpoint_open: Open the endpoint
763  *
764  * Called from hw_params to assign the endpoint to the substream.
765  * It's reference-counted, and only the first opener is allowed to set up
766  * arbitrary parameters.  The later opener must be compatible with the
767  * former opened parameters.
768  * The endpoint needs to be closed via snd_usb_endpoint_close() later.
769  *
770  * Note that this function doesn't configure the endpoint.  The substream
771  * needs to set it up later via snd_usb_endpoint_set_params() and
772  * snd_usb_endpoint_prepare().
773  */
774 struct snd_usb_endpoint *
775 snd_usb_endpoint_open(struct snd_usb_audio *chip,
776 		      const struct audioformat *fp,
777 		      const struct snd_pcm_hw_params *params,
778 		      bool is_sync_ep,
779 		      bool fixed_rate)
780 {
781 	struct snd_usb_endpoint *ep;
782 	int ep_num = is_sync_ep ? fp->sync_ep : fp->endpoint;
783 
784 	mutex_lock(&chip->mutex);
785 	ep = snd_usb_get_endpoint(chip, ep_num);
786 	if (!ep) {
787 		usb_audio_err(chip, "Cannot find EP 0x%x to open\n", ep_num);
788 		goto unlock;
789 	}
790 
791 	if (!ep->opened) {
792 		if (is_sync_ep) {
793 			ep->iface = fp->sync_iface;
794 			ep->altsetting = fp->sync_altsetting;
795 			ep->ep_idx = fp->sync_ep_idx;
796 		} else {
797 			ep->iface = fp->iface;
798 			ep->altsetting = fp->altsetting;
799 			ep->ep_idx = fp->ep_idx;
800 		}
801 		usb_audio_dbg(chip, "Open EP 0x%x, iface=%d:%d, idx=%d\n",
802 			      ep_num, ep->iface, ep->altsetting, ep->ep_idx);
803 
804 		ep->iface_ref = iface_ref_find(chip, ep->iface);
805 		if (!ep->iface_ref) {
806 			ep = NULL;
807 			goto unlock;
808 		}
809 
810 		if (fp->protocol != UAC_VERSION_1) {
811 			ep->clock_ref = clock_ref_find(chip, fp->clock);
812 			if (!ep->clock_ref) {
813 				ep = NULL;
814 				goto unlock;
815 			}
816 			ep->clock_ref->opened++;
817 		}
818 
819 		ep->cur_audiofmt = fp;
820 		ep->cur_channels = fp->channels;
821 		ep->cur_rate = params_rate(params);
822 		ep->cur_format = params_format(params);
823 		ep->cur_frame_bytes = snd_pcm_format_physical_width(ep->cur_format) *
824 			ep->cur_channels / 8;
825 		ep->cur_period_frames = params_period_size(params);
826 		ep->cur_period_bytes = ep->cur_period_frames * ep->cur_frame_bytes;
827 		ep->cur_buffer_periods = params_periods(params);
828 
829 		if (ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
830 			endpoint_set_syncinterval(chip, ep);
831 
832 		ep->implicit_fb_sync = fp->implicit_fb;
833 		ep->need_setup = true;
834 		ep->need_prepare = true;
835 		ep->fixed_rate = fixed_rate;
836 
837 		usb_audio_dbg(chip, "  channels=%d, rate=%d, format=%s, period_bytes=%d, periods=%d, implicit_fb=%d\n",
838 			      ep->cur_channels, ep->cur_rate,
839 			      snd_pcm_format_name(ep->cur_format),
840 			      ep->cur_period_bytes, ep->cur_buffer_periods,
841 			      ep->implicit_fb_sync);
842 
843 	} else {
844 		if (WARN_ON(!ep->iface_ref)) {
845 			ep = NULL;
846 			goto unlock;
847 		}
848 
849 		if (!endpoint_compatible(ep, fp, params)) {
850 			usb_audio_err(chip, "Incompatible EP setup for 0x%x\n",
851 				      ep_num);
852 			ep = NULL;
853 			goto unlock;
854 		}
855 
856 		usb_audio_dbg(chip, "Reopened EP 0x%x (count %d)\n",
857 			      ep_num, ep->opened);
858 	}
859 
860 	if (!ep->iface_ref->opened++)
861 		ep->iface_ref->need_setup = true;
862 
863 	ep->opened++;
864 
865  unlock:
866 	mutex_unlock(&chip->mutex);
867 	return ep;
868 }
869 
870 /*
871  * snd_usb_endpoint_set_sync: Link data and sync endpoints
872  *
873  * Pass NULL to sync_ep to unlink again
874  */
875 void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
876 			       struct snd_usb_endpoint *data_ep,
877 			       struct snd_usb_endpoint *sync_ep)
878 {
879 	data_ep->sync_source = sync_ep;
880 }
881 
882 /*
883  * Set data endpoint callbacks and the assigned data stream
884  *
885  * Called at PCM trigger and cleanups.
886  * Pass NULL to deactivate each callback.
887  */
888 void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
889 				   int (*prepare)(struct snd_usb_substream *subs,
890 						  struct urb *urb,
891 						  bool in_stream_lock),
892 				   void (*retire)(struct snd_usb_substream *subs,
893 						  struct urb *urb),
894 				   struct snd_usb_substream *data_subs)
895 {
896 	ep->prepare_data_urb = prepare;
897 	ep->retire_data_urb = retire;
898 	if (data_subs)
899 		ep->lowlatency_playback = data_subs->lowlatency_playback;
900 	else
901 		ep->lowlatency_playback = false;
902 	WRITE_ONCE(ep->data_subs, data_subs);
903 }
904 
905 static int endpoint_set_interface(struct snd_usb_audio *chip,
906 				  struct snd_usb_endpoint *ep,
907 				  bool set)
908 {
909 	int altset = set ? ep->altsetting : 0;
910 	int err;
911 
912 	if (ep->iface_ref->altset == altset)
913 		return 0;
914 
915 	usb_audio_dbg(chip, "Setting usb interface %d:%d for EP 0x%x\n",
916 		      ep->iface, altset, ep->ep_num);
917 	err = usb_set_interface(chip->dev, ep->iface, altset);
918 	if (err < 0) {
919 		usb_audio_err_ratelimited(
920 			chip, "%d:%d: usb_set_interface failed (%d)\n",
921 			ep->iface, altset, err);
922 		return err;
923 	}
924 
925 	if (chip->quirk_flags & QUIRK_FLAG_IFACE_DELAY)
926 		msleep(50);
927 	ep->iface_ref->altset = altset;
928 	return 0;
929 }
930 
931 /*
932  * snd_usb_endpoint_close: Close the endpoint
933  *
934  * Unreference the already opened endpoint via snd_usb_endpoint_open().
935  */
936 void snd_usb_endpoint_close(struct snd_usb_audio *chip,
937 			    struct snd_usb_endpoint *ep)
938 {
939 	mutex_lock(&chip->mutex);
940 	usb_audio_dbg(chip, "Closing EP 0x%x (count %d)\n",
941 		      ep->ep_num, ep->opened);
942 
943 	if (!--ep->iface_ref->opened &&
944 		!(chip->quirk_flags & QUIRK_FLAG_IFACE_SKIP_CLOSE))
945 		endpoint_set_interface(chip, ep, false);
946 
947 	if (!--ep->opened) {
948 		if (ep->clock_ref) {
949 			if (!--ep->clock_ref->opened)
950 				ep->clock_ref->rate = 0;
951 		}
952 		ep->iface = 0;
953 		ep->altsetting = 0;
954 		ep->cur_audiofmt = NULL;
955 		ep->cur_rate = 0;
956 		ep->iface_ref = NULL;
957 		ep->clock_ref = NULL;
958 		usb_audio_dbg(chip, "EP 0x%x closed\n", ep->ep_num);
959 	}
960 	mutex_unlock(&chip->mutex);
961 }
962 
963 /* Prepare for suspening EP, called from the main suspend handler */
964 void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep)
965 {
966 	ep->need_prepare = true;
967 	if (ep->iface_ref)
968 		ep->iface_ref->need_setup = true;
969 	if (ep->clock_ref)
970 		ep->clock_ref->rate = 0;
971 }
972 
973 /*
974  *  wait until all urbs are processed.
975  */
976 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
977 {
978 	unsigned long end_time = jiffies + msecs_to_jiffies(1000);
979 	int alive;
980 
981 	if (atomic_read(&ep->state) != EP_STATE_STOPPING)
982 		return 0;
983 
984 	do {
985 		alive = atomic_read(&ep->submitted_urbs);
986 		if (!alive)
987 			break;
988 
989 		schedule_timeout_uninterruptible(1);
990 	} while (time_before(jiffies, end_time));
991 
992 	if (alive)
993 		usb_audio_err(ep->chip,
994 			"timeout: still %d active urbs on EP #%x\n",
995 			alive, ep->ep_num);
996 
997 	if (ep_state_update(ep, EP_STATE_STOPPING, EP_STATE_STOPPED)) {
998 		ep->sync_sink = NULL;
999 		snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
1000 	}
1001 
1002 	return 0;
1003 }
1004 
1005 /* sync the pending stop operation;
1006  * this function itself doesn't trigger the stop operation
1007  */
1008 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
1009 {
1010 	if (ep)
1011 		wait_clear_urbs(ep);
1012 }
1013 
1014 /*
1015  * Stop active urbs
1016  *
1017  * This function moves the EP to STOPPING state if it's being RUNNING.
1018  */
1019 static int stop_urbs(struct snd_usb_endpoint *ep, bool force, bool keep_pending)
1020 {
1021 	unsigned int i;
1022 	unsigned long flags;
1023 
1024 	if (!force && atomic_read(&ep->running))
1025 		return -EBUSY;
1026 
1027 	if (!ep_state_update(ep, EP_STATE_RUNNING, EP_STATE_STOPPING))
1028 		return 0;
1029 
1030 	spin_lock_irqsave(&ep->lock, flags);
1031 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
1032 	ep->next_packet_head = 0;
1033 	ep->next_packet_queued = 0;
1034 	spin_unlock_irqrestore(&ep->lock, flags);
1035 
1036 	if (keep_pending)
1037 		return 0;
1038 
1039 	for (i = 0; i < ep->nurbs; i++) {
1040 		if (test_bit(i, &ep->active_mask)) {
1041 			if (!test_and_set_bit(i, &ep->unlink_mask)) {
1042 				struct urb *u = ep->urb[i].urb;
1043 				usb_unlink_urb(u);
1044 			}
1045 		}
1046 	}
1047 
1048 	return 0;
1049 }
1050 
1051 /*
1052  * release an endpoint's urbs
1053  */
1054 static int release_urbs(struct snd_usb_endpoint *ep, bool force)
1055 {
1056 	int i, err;
1057 
1058 	/* route incoming urbs to nirvana */
1059 	snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
1060 
1061 	/* stop and unlink urbs */
1062 	err = stop_urbs(ep, force, false);
1063 	if (err)
1064 		return err;
1065 
1066 	wait_clear_urbs(ep);
1067 
1068 	for (i = 0; i < ep->nurbs; i++)
1069 		release_urb_ctx(&ep->urb[i]);
1070 
1071 	usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
1072 			  ep->syncbuf, ep->sync_dma);
1073 
1074 	ep->syncbuf = NULL;
1075 	ep->nurbs = 0;
1076 	return 0;
1077 }
1078 
1079 /*
1080  * configure a data endpoint
1081  */
1082 static int data_ep_set_params(struct snd_usb_endpoint *ep)
1083 {
1084 	struct snd_usb_audio *chip = ep->chip;
1085 	unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
1086 	unsigned int max_packs_per_period, urbs_per_period, urb_packs;
1087 	unsigned int max_urbs, i;
1088 	const struct audioformat *fmt = ep->cur_audiofmt;
1089 	int frame_bits = ep->cur_frame_bytes * 8;
1090 	int tx_length_quirk = (has_tx_length_quirk(chip) &&
1091 			       usb_pipeout(ep->pipe));
1092 
1093 	usb_audio_dbg(chip, "Setting params for data EP 0x%x, pipe 0x%x\n",
1094 		      ep->ep_num, ep->pipe);
1095 
1096 	if (ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
1097 		/*
1098 		 * When operating in DSD DOP mode, the size of a sample frame
1099 		 * in hardware differs from the actual physical format width
1100 		 * because we need to make room for the DOP markers.
1101 		 */
1102 		frame_bits += ep->cur_channels << 3;
1103 	}
1104 
1105 	ep->datainterval = fmt->datainterval;
1106 	ep->stride = frame_bits >> 3;
1107 
1108 	switch (ep->cur_format) {
1109 	case SNDRV_PCM_FORMAT_U8:
1110 		ep->silence_value = 0x80;
1111 		break;
1112 	case SNDRV_PCM_FORMAT_DSD_U8:
1113 	case SNDRV_PCM_FORMAT_DSD_U16_LE:
1114 	case SNDRV_PCM_FORMAT_DSD_U32_LE:
1115 	case SNDRV_PCM_FORMAT_DSD_U16_BE:
1116 	case SNDRV_PCM_FORMAT_DSD_U32_BE:
1117 		ep->silence_value = 0x69;
1118 		break;
1119 	default:
1120 		ep->silence_value = 0;
1121 	}
1122 
1123 	/* assume max. frequency is 50% higher than nominal */
1124 	ep->freqmax = ep->freqn + (ep->freqn >> 1);
1125 	/* Round up freqmax to nearest integer in order to calculate maximum
1126 	 * packet size, which must represent a whole number of frames.
1127 	 * This is accomplished by adding 0x0.ffff before converting the
1128 	 * Q16.16 format into integer.
1129 	 * In order to accurately calculate the maximum packet size when
1130 	 * the data interval is more than 1 (i.e. ep->datainterval > 0),
1131 	 * multiply by the data interval prior to rounding. For instance,
1132 	 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
1133 	 * frames with a data interval of 1, but 11 (10.25) frames with a
1134 	 * data interval of 2.
1135 	 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
1136 	 * maximum datainterval value of 3, at USB full speed, higher for
1137 	 * USB high speed, noting that ep->freqmax is in units of
1138 	 * frames per packet in Q16.16 format.)
1139 	 */
1140 	maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
1141 			 (frame_bits >> 3);
1142 	if (tx_length_quirk)
1143 		maxsize += sizeof(__le32); /* Space for length descriptor */
1144 	/* but wMaxPacketSize might reduce this */
1145 	if (ep->maxpacksize && ep->maxpacksize < maxsize) {
1146 		/* whatever fits into a max. size packet */
1147 		unsigned int data_maxsize = maxsize = ep->maxpacksize;
1148 
1149 		if (tx_length_quirk)
1150 			/* Need to remove the length descriptor to calc freq */
1151 			data_maxsize -= sizeof(__le32);
1152 		ep->freqmax = (data_maxsize / (frame_bits >> 3))
1153 				<< (16 - ep->datainterval);
1154 	}
1155 
1156 	if (ep->fill_max)
1157 		ep->curpacksize = ep->maxpacksize;
1158 	else
1159 		ep->curpacksize = maxsize;
1160 
1161 	if (snd_usb_get_speed(chip->dev) != USB_SPEED_FULL) {
1162 		packs_per_ms = 8 >> ep->datainterval;
1163 		max_packs_per_urb = MAX_PACKS_HS;
1164 	} else {
1165 		packs_per_ms = 1;
1166 		max_packs_per_urb = MAX_PACKS;
1167 	}
1168 	if (ep->sync_source && !ep->implicit_fb_sync)
1169 		max_packs_per_urb = min(max_packs_per_urb,
1170 					1U << ep->sync_source->syncinterval);
1171 	max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
1172 
1173 	/*
1174 	 * Capture endpoints need to use small URBs because there's no way
1175 	 * to tell in advance where the next period will end, and we don't
1176 	 * want the next URB to complete much after the period ends.
1177 	 *
1178 	 * Playback endpoints with implicit sync much use the same parameters
1179 	 * as their corresponding capture endpoint.
1180 	 */
1181 	if (usb_pipein(ep->pipe) || ep->implicit_fb_sync) {
1182 
1183 		/* make capture URBs <= 1 ms and smaller than a period */
1184 		urb_packs = min(max_packs_per_urb, packs_per_ms);
1185 		while (urb_packs > 1 && urb_packs * maxsize >= ep->cur_period_bytes)
1186 			urb_packs >>= 1;
1187 		ep->nurbs = MAX_URBS;
1188 
1189 	/*
1190 	 * Playback endpoints without implicit sync are adjusted so that
1191 	 * a period fits as evenly as possible in the smallest number of
1192 	 * URBs.  The total number of URBs is adjusted to the size of the
1193 	 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
1194 	 */
1195 	} else {
1196 		/* determine how small a packet can be */
1197 		minsize = (ep->freqn >> (16 - ep->datainterval)) *
1198 				(frame_bits >> 3);
1199 		/* with sync from device, assume it can be 12% lower */
1200 		if (ep->sync_source)
1201 			minsize -= minsize >> 3;
1202 		minsize = max(minsize, 1u);
1203 
1204 		/* how many packets will contain an entire ALSA period? */
1205 		max_packs_per_period = DIV_ROUND_UP(ep->cur_period_bytes, minsize);
1206 
1207 		/* how many URBs will contain a period? */
1208 		urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
1209 				max_packs_per_urb);
1210 		/* how many packets are needed in each URB? */
1211 		urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
1212 
1213 		/* limit the number of frames in a single URB */
1214 		ep->max_urb_frames = DIV_ROUND_UP(ep->cur_period_frames,
1215 						  urbs_per_period);
1216 
1217 		/* try to use enough URBs to contain an entire ALSA buffer */
1218 		max_urbs = min((unsigned) MAX_URBS,
1219 				MAX_QUEUE * packs_per_ms / urb_packs);
1220 		ep->nurbs = min(max_urbs, urbs_per_period * ep->cur_buffer_periods);
1221 	}
1222 
1223 	/* allocate and initialize data urbs */
1224 	for (i = 0; i < ep->nurbs; i++) {
1225 		struct snd_urb_ctx *u = &ep->urb[i];
1226 		u->index = i;
1227 		u->ep = ep;
1228 		u->packets = urb_packs;
1229 		u->buffer_size = maxsize * u->packets;
1230 
1231 		if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
1232 			u->packets++; /* for transfer delimiter */
1233 		u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
1234 		if (!u->urb)
1235 			goto out_of_memory;
1236 
1237 		u->urb->transfer_buffer =
1238 			usb_alloc_coherent(chip->dev, u->buffer_size,
1239 					   GFP_KERNEL, &u->urb->transfer_dma);
1240 		if (!u->urb->transfer_buffer)
1241 			goto out_of_memory;
1242 		u->urb->pipe = ep->pipe;
1243 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1244 		u->urb->interval = 1 << ep->datainterval;
1245 		u->urb->context = u;
1246 		u->urb->complete = snd_complete_urb;
1247 		INIT_LIST_HEAD(&u->ready_list);
1248 	}
1249 
1250 	return 0;
1251 
1252 out_of_memory:
1253 	release_urbs(ep, false);
1254 	return -ENOMEM;
1255 }
1256 
1257 /*
1258  * configure a sync endpoint
1259  */
1260 static int sync_ep_set_params(struct snd_usb_endpoint *ep)
1261 {
1262 	struct snd_usb_audio *chip = ep->chip;
1263 	int i;
1264 
1265 	usb_audio_dbg(chip, "Setting params for sync EP 0x%x, pipe 0x%x\n",
1266 		      ep->ep_num, ep->pipe);
1267 
1268 	ep->syncbuf = usb_alloc_coherent(chip->dev, SYNC_URBS * 4,
1269 					 GFP_KERNEL, &ep->sync_dma);
1270 	if (!ep->syncbuf)
1271 		return -ENOMEM;
1272 
1273 	ep->nurbs = SYNC_URBS;
1274 	for (i = 0; i < SYNC_URBS; i++) {
1275 		struct snd_urb_ctx *u = &ep->urb[i];
1276 		u->index = i;
1277 		u->ep = ep;
1278 		u->packets = 1;
1279 		u->urb = usb_alloc_urb(1, GFP_KERNEL);
1280 		if (!u->urb)
1281 			goto out_of_memory;
1282 		u->urb->transfer_buffer = ep->syncbuf + i * 4;
1283 		u->urb->transfer_dma = ep->sync_dma + i * 4;
1284 		u->urb->transfer_buffer_length = 4;
1285 		u->urb->pipe = ep->pipe;
1286 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1287 		u->urb->number_of_packets = 1;
1288 		u->urb->interval = 1 << ep->syncinterval;
1289 		u->urb->context = u;
1290 		u->urb->complete = snd_complete_urb;
1291 	}
1292 
1293 	return 0;
1294 
1295 out_of_memory:
1296 	release_urbs(ep, false);
1297 	return -ENOMEM;
1298 }
1299 
1300 /* update the rate of the referred clock; return the actual rate */
1301 static int update_clock_ref_rate(struct snd_usb_audio *chip,
1302 				 struct snd_usb_endpoint *ep)
1303 {
1304 	struct snd_usb_clock_ref *clock = ep->clock_ref;
1305 	int rate = ep->cur_rate;
1306 
1307 	if (!clock || clock->rate == rate)
1308 		return rate;
1309 	if (clock->rate) {
1310 		if (atomic_read(&clock->locked))
1311 			return clock->rate;
1312 		if (clock->rate != rate) {
1313 			usb_audio_err(chip, "Mismatched sample rate %d vs %d for EP 0x%x\n",
1314 				      clock->rate, rate, ep->ep_num);
1315 			return clock->rate;
1316 		}
1317 	}
1318 	clock->rate = rate;
1319 	clock->need_setup = true;
1320 	return rate;
1321 }
1322 
1323 /*
1324  * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
1325  *
1326  * It's called either from hw_params callback.
1327  * Determine the number of URBs to be used on this endpoint.
1328  * An endpoint must be configured before it can be started.
1329  * An endpoint that is already running can not be reconfigured.
1330  */
1331 int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
1332 				struct snd_usb_endpoint *ep)
1333 {
1334 	const struct audioformat *fmt = ep->cur_audiofmt;
1335 	int err = 0;
1336 
1337 	mutex_lock(&chip->mutex);
1338 	if (!ep->need_setup)
1339 		goto unlock;
1340 
1341 	/* release old buffers, if any */
1342 	err = release_urbs(ep, false);
1343 	if (err < 0)
1344 		goto unlock;
1345 
1346 	ep->datainterval = fmt->datainterval;
1347 	ep->maxpacksize = fmt->maxpacksize;
1348 	ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
1349 
1350 	if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) {
1351 		ep->freqn = get_usb_full_speed_rate(ep->cur_rate);
1352 		ep->pps = 1000 >> ep->datainterval;
1353 	} else {
1354 		ep->freqn = get_usb_high_speed_rate(ep->cur_rate);
1355 		ep->pps = 8000 >> ep->datainterval;
1356 	}
1357 
1358 	ep->sample_rem = ep->cur_rate % ep->pps;
1359 	ep->packsize[0] = ep->cur_rate / ep->pps;
1360 	ep->packsize[1] = (ep->cur_rate + (ep->pps - 1)) / ep->pps;
1361 
1362 	/* calculate the frequency in 16.16 format */
1363 	ep->freqm = ep->freqn;
1364 	ep->freqshift = INT_MIN;
1365 
1366 	ep->phase = 0;
1367 
1368 	switch (ep->type) {
1369 	case  SND_USB_ENDPOINT_TYPE_DATA:
1370 		err = data_ep_set_params(ep);
1371 		break;
1372 	case  SND_USB_ENDPOINT_TYPE_SYNC:
1373 		err = sync_ep_set_params(ep);
1374 		break;
1375 	default:
1376 		err = -EINVAL;
1377 	}
1378 
1379 	usb_audio_dbg(chip, "Set up %d URBS, ret=%d\n", ep->nurbs, err);
1380 
1381 	if (err < 0)
1382 		goto unlock;
1383 
1384 	/* some unit conversions in runtime */
1385 	ep->maxframesize = ep->maxpacksize / ep->cur_frame_bytes;
1386 	ep->curframesize = ep->curpacksize / ep->cur_frame_bytes;
1387 
1388 	err = update_clock_ref_rate(chip, ep);
1389 	if (err >= 0) {
1390 		ep->need_setup = false;
1391 		err = 0;
1392 	}
1393 
1394  unlock:
1395 	mutex_unlock(&chip->mutex);
1396 	return err;
1397 }
1398 
1399 static int init_sample_rate(struct snd_usb_audio *chip,
1400 			    struct snd_usb_endpoint *ep)
1401 {
1402 	struct snd_usb_clock_ref *clock = ep->clock_ref;
1403 	int rate, err;
1404 
1405 	rate = update_clock_ref_rate(chip, ep);
1406 	if (rate < 0)
1407 		return rate;
1408 	if (clock && !clock->need_setup)
1409 		return 0;
1410 
1411 	if (!ep->fixed_rate) {
1412 		err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, rate);
1413 		if (err < 0) {
1414 			if (clock)
1415 				clock->rate = 0; /* reset rate */
1416 			return err;
1417 		}
1418 	}
1419 
1420 	if (clock)
1421 		clock->need_setup = false;
1422 	return 0;
1423 }
1424 
1425 /*
1426  * snd_usb_endpoint_prepare: Prepare the endpoint
1427  *
1428  * This function sets up the EP to be fully usable state.
1429  * It's called either from prepare callback.
1430  * The function checks need_setup flag, and performs nothing unless needed,
1431  * so it's safe to call this multiple times.
1432  *
1433  * This returns zero if unchanged, 1 if the configuration has changed,
1434  * or a negative error code.
1435  */
1436 int snd_usb_endpoint_prepare(struct snd_usb_audio *chip,
1437 			     struct snd_usb_endpoint *ep)
1438 {
1439 	bool iface_first;
1440 	int err = 0;
1441 
1442 	mutex_lock(&chip->mutex);
1443 	if (WARN_ON(!ep->iface_ref))
1444 		goto unlock;
1445 	if (!ep->need_prepare)
1446 		goto unlock;
1447 
1448 	/* If the interface has been already set up, just set EP parameters */
1449 	if (!ep->iface_ref->need_setup) {
1450 		/* sample rate setup of UAC1 is per endpoint, and we need
1451 		 * to update at each EP configuration
1452 		 */
1453 		if (ep->cur_audiofmt->protocol == UAC_VERSION_1) {
1454 			err = init_sample_rate(chip, ep);
1455 			if (err < 0)
1456 				goto unlock;
1457 		}
1458 		goto done;
1459 	}
1460 
1461 	/* Need to deselect altsetting at first */
1462 	endpoint_set_interface(chip, ep, false);
1463 
1464 	/* Some UAC1 devices (e.g. Yamaha THR10) need the host interface
1465 	 * to be set up before parameter setups
1466 	 */
1467 	iface_first = ep->cur_audiofmt->protocol == UAC_VERSION_1;
1468 	/* Workaround for devices that require the interface setup at first like UAC1 */
1469 	if (chip->quirk_flags & QUIRK_FLAG_SET_IFACE_FIRST)
1470 		iface_first = true;
1471 	if (iface_first) {
1472 		err = endpoint_set_interface(chip, ep, true);
1473 		if (err < 0)
1474 			goto unlock;
1475 	}
1476 
1477 	err = snd_usb_init_pitch(chip, ep->cur_audiofmt);
1478 	if (err < 0)
1479 		goto unlock;
1480 
1481 	err = init_sample_rate(chip, ep);
1482 	if (err < 0)
1483 		goto unlock;
1484 
1485 	err = snd_usb_select_mode_quirk(chip, ep->cur_audiofmt);
1486 	if (err < 0)
1487 		goto unlock;
1488 
1489 	/* for UAC2/3, enable the interface altset here at last */
1490 	if (!iface_first) {
1491 		err = endpoint_set_interface(chip, ep, true);
1492 		if (err < 0)
1493 			goto unlock;
1494 	}
1495 
1496 	ep->iface_ref->need_setup = false;
1497 
1498  done:
1499 	ep->need_prepare = false;
1500 	err = 1;
1501 
1502 unlock:
1503 	mutex_unlock(&chip->mutex);
1504 	return err;
1505 }
1506 
1507 /* get the current rate set to the given clock by any endpoint */
1508 int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock)
1509 {
1510 	struct snd_usb_clock_ref *ref;
1511 	int rate = 0;
1512 
1513 	if (!clock)
1514 		return 0;
1515 	mutex_lock(&chip->mutex);
1516 	list_for_each_entry(ref, &chip->clock_ref_list, list) {
1517 		if (ref->clock == clock) {
1518 			rate = ref->rate;
1519 			break;
1520 		}
1521 	}
1522 	mutex_unlock(&chip->mutex);
1523 	return rate;
1524 }
1525 
1526 /**
1527  * snd_usb_endpoint_start: start an snd_usb_endpoint
1528  *
1529  * @ep: the endpoint to start
1530  *
1531  * A call to this function will increment the running count of the endpoint.
1532  * In case it is not already running, the URBs for this endpoint will be
1533  * submitted. Otherwise, this function does nothing.
1534  *
1535  * Must be balanced to calls of snd_usb_endpoint_stop().
1536  *
1537  * Returns an error if the URB submission failed, 0 in all other cases.
1538  */
1539 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
1540 {
1541 	bool is_playback = usb_pipeout(ep->pipe);
1542 	int err;
1543 	unsigned int i;
1544 
1545 	if (atomic_read(&ep->chip->shutdown))
1546 		return -EBADFD;
1547 
1548 	if (ep->sync_source)
1549 		WRITE_ONCE(ep->sync_source->sync_sink, ep);
1550 
1551 	usb_audio_dbg(ep->chip, "Starting %s EP 0x%x (running %d)\n",
1552 		      ep_type_name(ep->type), ep->ep_num,
1553 		      atomic_read(&ep->running));
1554 
1555 	/* already running? */
1556 	if (atomic_inc_return(&ep->running) != 1)
1557 		return 0;
1558 
1559 	if (ep->clock_ref)
1560 		atomic_inc(&ep->clock_ref->locked);
1561 
1562 	ep->active_mask = 0;
1563 	ep->unlink_mask = 0;
1564 	ep->phase = 0;
1565 	ep->sample_accum = 0;
1566 
1567 	snd_usb_endpoint_start_quirk(ep);
1568 
1569 	/*
1570 	 * If this endpoint has a data endpoint as implicit feedback source,
1571 	 * don't start the urbs here. Instead, mark them all as available,
1572 	 * wait for the record urbs to return and queue the playback urbs
1573 	 * from that context.
1574 	 */
1575 
1576 	if (!ep_state_update(ep, EP_STATE_STOPPED, EP_STATE_RUNNING))
1577 		goto __error;
1578 
1579 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1580 	    !(ep->chip->quirk_flags & QUIRK_FLAG_PLAYBACK_FIRST)) {
1581 		usb_audio_dbg(ep->chip, "No URB submission due to implicit fb sync\n");
1582 		i = 0;
1583 		goto fill_rest;
1584 	}
1585 
1586 	for (i = 0; i < ep->nurbs; i++) {
1587 		struct urb *urb = ep->urb[i].urb;
1588 
1589 		if (snd_BUG_ON(!urb))
1590 			goto __error;
1591 
1592 		if (is_playback)
1593 			err = prepare_outbound_urb(ep, urb->context, true);
1594 		else
1595 			err = prepare_inbound_urb(ep, urb->context);
1596 		if (err < 0) {
1597 			/* stop filling at applptr */
1598 			if (err == -EAGAIN)
1599 				break;
1600 			usb_audio_dbg(ep->chip,
1601 				      "EP 0x%x: failed to prepare urb: %d\n",
1602 				      ep->ep_num, err);
1603 			goto __error;
1604 		}
1605 
1606 		err = usb_submit_urb(urb, GFP_ATOMIC);
1607 		if (err < 0) {
1608 			usb_audio_err(ep->chip,
1609 				"cannot submit urb %d, error %d: %s\n",
1610 				i, err, usb_error_string(err));
1611 			goto __error;
1612 		}
1613 		set_bit(i, &ep->active_mask);
1614 		atomic_inc(&ep->submitted_urbs);
1615 	}
1616 
1617 	if (!i) {
1618 		usb_audio_dbg(ep->chip, "XRUN at starting EP 0x%x\n",
1619 			      ep->ep_num);
1620 		goto __error;
1621 	}
1622 
1623 	usb_audio_dbg(ep->chip, "%d URBs submitted for EP 0x%x\n",
1624 		      i, ep->ep_num);
1625 
1626  fill_rest:
1627 	/* put the remaining URBs to ready list */
1628 	if (is_playback) {
1629 		for (; i < ep->nurbs; i++)
1630 			push_back_to_ready_list(ep, ep->urb + i);
1631 	}
1632 
1633 	return 0;
1634 
1635 __error:
1636 	snd_usb_endpoint_stop(ep, false);
1637 	return -EPIPE;
1638 }
1639 
1640 /**
1641  * snd_usb_endpoint_stop: stop an snd_usb_endpoint
1642  *
1643  * @ep: the endpoint to stop (may be NULL)
1644  * @keep_pending: keep in-flight URBs
1645  *
1646  * A call to this function will decrement the running count of the endpoint.
1647  * In case the last user has requested the endpoint stop, the URBs will
1648  * actually be deactivated.
1649  *
1650  * Must be balanced to calls of snd_usb_endpoint_start().
1651  *
1652  * The caller needs to synchronize the pending stop operation via
1653  * snd_usb_endpoint_sync_pending_stop().
1654  */
1655 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending)
1656 {
1657 	if (!ep)
1658 		return;
1659 
1660 	usb_audio_dbg(ep->chip, "Stopping %s EP 0x%x (running %d)\n",
1661 		      ep_type_name(ep->type), ep->ep_num,
1662 		      atomic_read(&ep->running));
1663 
1664 	if (snd_BUG_ON(!atomic_read(&ep->running)))
1665 		return;
1666 
1667 	if (!atomic_dec_return(&ep->running)) {
1668 		if (ep->sync_source)
1669 			WRITE_ONCE(ep->sync_source->sync_sink, NULL);
1670 		stop_urbs(ep, false, keep_pending);
1671 		if (ep->clock_ref)
1672 			atomic_dec(&ep->clock_ref->locked);
1673 
1674 		if (ep->chip->quirk_flags & QUIRK_FLAG_FORCE_IFACE_RESET &&
1675 		    usb_pipeout(ep->pipe)) {
1676 			ep->need_prepare = true;
1677 			if (ep->iface_ref)
1678 				ep->iface_ref->need_setup = true;
1679 		}
1680 	}
1681 }
1682 
1683 /**
1684  * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1685  *
1686  * @ep: the endpoint to release
1687  *
1688  * This function does not care for the endpoint's running count but will tear
1689  * down all the streaming URBs immediately.
1690  */
1691 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1692 {
1693 	release_urbs(ep, true);
1694 }
1695 
1696 /**
1697  * snd_usb_endpoint_free_all: Free the resources of an snd_usb_endpoint
1698  * @chip: The chip
1699  *
1700  * This free all endpoints and those resources
1701  */
1702 void snd_usb_endpoint_free_all(struct snd_usb_audio *chip)
1703 {
1704 	struct snd_usb_endpoint *ep, *en;
1705 	struct snd_usb_iface_ref *ip, *in;
1706 	struct snd_usb_clock_ref *cp, *cn;
1707 
1708 	list_for_each_entry_safe(ep, en, &chip->ep_list, list)
1709 		kfree(ep);
1710 
1711 	list_for_each_entry_safe(ip, in, &chip->iface_ref_list, list)
1712 		kfree(ip);
1713 
1714 	list_for_each_entry_safe(cp, cn, &chip->clock_ref_list, list)
1715 		kfree(cp);
1716 }
1717 
1718 /*
1719  * snd_usb_handle_sync_urb: parse an USB sync packet
1720  *
1721  * @ep: the endpoint to handle the packet
1722  * @sender: the sending endpoint
1723  * @urb: the received packet
1724  *
1725  * This function is called from the context of an endpoint that received
1726  * the packet and is used to let another endpoint object handle the payload.
1727  */
1728 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1729 				    struct snd_usb_endpoint *sender,
1730 				    const struct urb *urb)
1731 {
1732 	int shift;
1733 	unsigned int f;
1734 	unsigned long flags;
1735 
1736 	snd_BUG_ON(ep == sender);
1737 
1738 	/*
1739 	 * In case the endpoint is operating in implicit feedback mode, prepare
1740 	 * a new outbound URB that has the same layout as the received packet
1741 	 * and add it to the list of pending urbs. queue_pending_output_urbs()
1742 	 * will take care of them later.
1743 	 */
1744 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1745 	    atomic_read(&ep->running)) {
1746 
1747 		/* implicit feedback case */
1748 		int i, bytes = 0;
1749 		struct snd_urb_ctx *in_ctx;
1750 		struct snd_usb_packet_info *out_packet;
1751 
1752 		in_ctx = urb->context;
1753 
1754 		/* Count overall packet size */
1755 		for (i = 0; i < in_ctx->packets; i++)
1756 			if (urb->iso_frame_desc[i].status == 0)
1757 				bytes += urb->iso_frame_desc[i].actual_length;
1758 
1759 		/*
1760 		 * skip empty packets. At least M-Audio's Fast Track Ultra stops
1761 		 * streaming once it received a 0-byte OUT URB
1762 		 */
1763 		if (bytes == 0)
1764 			return;
1765 
1766 		spin_lock_irqsave(&ep->lock, flags);
1767 		if (ep->next_packet_queued >= ARRAY_SIZE(ep->next_packet)) {
1768 			spin_unlock_irqrestore(&ep->lock, flags);
1769 			usb_audio_err(ep->chip,
1770 				      "next package FIFO overflow EP 0x%x\n",
1771 				      ep->ep_num);
1772 			notify_xrun(ep);
1773 			return;
1774 		}
1775 
1776 		out_packet = next_packet_fifo_enqueue(ep);
1777 
1778 		/*
1779 		 * Iterate through the inbound packet and prepare the lengths
1780 		 * for the output packet. The OUT packet we are about to send
1781 		 * will have the same amount of payload bytes per stride as the
1782 		 * IN packet we just received. Since the actual size is scaled
1783 		 * by the stride, use the sender stride to calculate the length
1784 		 * in case the number of channels differ between the implicitly
1785 		 * fed-back endpoint and the synchronizing endpoint.
1786 		 */
1787 
1788 		out_packet->packets = in_ctx->packets;
1789 		for (i = 0; i < in_ctx->packets; i++) {
1790 			if (urb->iso_frame_desc[i].status == 0)
1791 				out_packet->packet_size[i] =
1792 					urb->iso_frame_desc[i].actual_length / sender->stride;
1793 			else
1794 				out_packet->packet_size[i] = 0;
1795 		}
1796 
1797 		spin_unlock_irqrestore(&ep->lock, flags);
1798 		snd_usb_queue_pending_output_urbs(ep, false);
1799 
1800 		return;
1801 	}
1802 
1803 	/*
1804 	 * process after playback sync complete
1805 	 *
1806 	 * Full speed devices report feedback values in 10.14 format as samples
1807 	 * per frame, high speed devices in 16.16 format as samples per
1808 	 * microframe.
1809 	 *
1810 	 * Because the Audio Class 1 spec was written before USB 2.0, many high
1811 	 * speed devices use a wrong interpretation, some others use an
1812 	 * entirely different format.
1813 	 *
1814 	 * Therefore, we cannot predict what format any particular device uses
1815 	 * and must detect it automatically.
1816 	 */
1817 
1818 	if (urb->iso_frame_desc[0].status != 0 ||
1819 	    urb->iso_frame_desc[0].actual_length < 3)
1820 		return;
1821 
1822 	f = le32_to_cpup(urb->transfer_buffer);
1823 	if (urb->iso_frame_desc[0].actual_length == 3)
1824 		f &= 0x00ffffff;
1825 	else
1826 		f &= 0x0fffffff;
1827 
1828 	if (f == 0)
1829 		return;
1830 
1831 	if (unlikely(sender->tenor_fb_quirk)) {
1832 		/*
1833 		 * Devices based on Tenor 8802 chipsets (TEAC UD-H01
1834 		 * and others) sometimes change the feedback value
1835 		 * by +/- 0x1.0000.
1836 		 */
1837 		if (f < ep->freqn - 0x8000)
1838 			f += 0xf000;
1839 		else if (f > ep->freqn + 0x8000)
1840 			f -= 0xf000;
1841 	} else if (unlikely(ep->freqshift == INT_MIN)) {
1842 		/*
1843 		 * The first time we see a feedback value, determine its format
1844 		 * by shifting it left or right until it matches the nominal
1845 		 * frequency value.  This assumes that the feedback does not
1846 		 * differ from the nominal value more than +50% or -25%.
1847 		 */
1848 		shift = 0;
1849 		while (f < ep->freqn - ep->freqn / 4) {
1850 			f <<= 1;
1851 			shift++;
1852 		}
1853 		while (f > ep->freqn + ep->freqn / 2) {
1854 			f >>= 1;
1855 			shift--;
1856 		}
1857 		ep->freqshift = shift;
1858 	} else if (ep->freqshift >= 0)
1859 		f <<= ep->freqshift;
1860 	else
1861 		f >>= -ep->freqshift;
1862 
1863 	if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1864 		/*
1865 		 * If the frequency looks valid, set it.
1866 		 * This value is referred to in prepare_playback_urb().
1867 		 */
1868 		spin_lock_irqsave(&ep->lock, flags);
1869 		ep->freqm = f;
1870 		spin_unlock_irqrestore(&ep->lock, flags);
1871 	} else {
1872 		/*
1873 		 * Out of range; maybe the shift value is wrong.
1874 		 * Reset it so that we autodetect again the next time.
1875 		 */
1876 		ep->freqshift = INT_MIN;
1877 	}
1878 }
1879 
1880