xref: /openbmc/linux/sound/usb/endpoint.c (revision aaa746ad)
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 void 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 			return;
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 			else
501 				notify_xrun(ep);
502 			return;
503 		}
504 
505 		err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
506 		if (err < 0) {
507 			usb_audio_err(ep->chip,
508 				      "Unable to submit urb #%d: %d at %s\n",
509 				      ctx->index, err, __func__);
510 			notify_xrun(ep);
511 			return;
512 		}
513 
514 		set_bit(ctx->index, &ep->active_mask);
515 		atomic_inc(&ep->submitted_urbs);
516 	}
517 }
518 
519 /*
520  * complete callback for urbs
521  */
522 static void snd_complete_urb(struct urb *urb)
523 {
524 	struct snd_urb_ctx *ctx = urb->context;
525 	struct snd_usb_endpoint *ep = ctx->ep;
526 	int err;
527 
528 	if (unlikely(urb->status == -ENOENT ||		/* unlinked */
529 		     urb->status == -ENODEV ||		/* device removed */
530 		     urb->status == -ECONNRESET ||	/* unlinked */
531 		     urb->status == -ESHUTDOWN))	/* device disabled */
532 		goto exit_clear;
533 	/* device disconnected */
534 	if (unlikely(atomic_read(&ep->chip->shutdown)))
535 		goto exit_clear;
536 
537 	if (unlikely(!ep_state_running(ep)))
538 		goto exit_clear;
539 
540 	if (usb_pipeout(ep->pipe)) {
541 		retire_outbound_urb(ep, ctx);
542 		/* can be stopped during retire callback */
543 		if (unlikely(!ep_state_running(ep)))
544 			goto exit_clear;
545 
546 		/* in low-latency and implicit-feedback modes, push back the
547 		 * URB to ready list at first, then process as much as possible
548 		 */
549 		if (ep->lowlatency_playback ||
550 		     snd_usb_endpoint_implicit_feedback_sink(ep)) {
551 			push_back_to_ready_list(ep, ctx);
552 			clear_bit(ctx->index, &ep->active_mask);
553 			snd_usb_queue_pending_output_urbs(ep, false);
554 			atomic_dec(&ep->submitted_urbs); /* decrement at last */
555 			return;
556 		}
557 
558 		/* in non-lowlatency mode, no error handling for prepare */
559 		prepare_outbound_urb(ep, ctx, false);
560 		/* can be stopped during prepare callback */
561 		if (unlikely(!ep_state_running(ep)))
562 			goto exit_clear;
563 	} else {
564 		retire_inbound_urb(ep, ctx);
565 		/* can be stopped during retire callback */
566 		if (unlikely(!ep_state_running(ep)))
567 			goto exit_clear;
568 
569 		prepare_inbound_urb(ep, ctx);
570 	}
571 
572 	err = usb_submit_urb(urb, GFP_ATOMIC);
573 	if (err == 0)
574 		return;
575 
576 	usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
577 	notify_xrun(ep);
578 
579 exit_clear:
580 	clear_bit(ctx->index, &ep->active_mask);
581 	atomic_dec(&ep->submitted_urbs);
582 }
583 
584 /*
585  * Find or create a refcount object for the given interface
586  *
587  * The objects are released altogether in snd_usb_endpoint_free_all()
588  */
589 static struct snd_usb_iface_ref *
590 iface_ref_find(struct snd_usb_audio *chip, int iface)
591 {
592 	struct snd_usb_iface_ref *ip;
593 
594 	list_for_each_entry(ip, &chip->iface_ref_list, list)
595 		if (ip->iface == iface)
596 			return ip;
597 
598 	ip = kzalloc(sizeof(*ip), GFP_KERNEL);
599 	if (!ip)
600 		return NULL;
601 	ip->iface = iface;
602 	list_add_tail(&ip->list, &chip->iface_ref_list);
603 	return ip;
604 }
605 
606 /* Similarly, a refcount object for clock */
607 static struct snd_usb_clock_ref *
608 clock_ref_find(struct snd_usb_audio *chip, int clock)
609 {
610 	struct snd_usb_clock_ref *ref;
611 
612 	list_for_each_entry(ref, &chip->clock_ref_list, list)
613 		if (ref->clock == clock)
614 			return ref;
615 
616 	ref = kzalloc(sizeof(*ref), GFP_KERNEL);
617 	if (!ref)
618 		return NULL;
619 	ref->clock = clock;
620 	atomic_set(&ref->locked, 0);
621 	list_add_tail(&ref->list, &chip->clock_ref_list);
622 	return ref;
623 }
624 
625 /*
626  * Get the existing endpoint object corresponding EP
627  * Returns NULL if not present.
628  */
629 struct snd_usb_endpoint *
630 snd_usb_get_endpoint(struct snd_usb_audio *chip, int ep_num)
631 {
632 	struct snd_usb_endpoint *ep;
633 
634 	list_for_each_entry(ep, &chip->ep_list, list) {
635 		if (ep->ep_num == ep_num)
636 			return ep;
637 	}
638 
639 	return NULL;
640 }
641 
642 #define ep_type_name(type) \
643 	(type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync")
644 
645 /**
646  * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
647  *
648  * @chip: The chip
649  * @ep_num: The number of the endpoint to use
650  * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
651  *
652  * If the requested endpoint has not been added to the given chip before,
653  * a new instance is created.
654  *
655  * Returns zero on success or a negative error code.
656  *
657  * New endpoints will be added to chip->ep_list and freed by
658  * calling snd_usb_endpoint_free_all().
659  *
660  * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
661  * bNumEndpoints > 1 beforehand.
662  */
663 int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type)
664 {
665 	struct snd_usb_endpoint *ep;
666 	bool is_playback;
667 
668 	ep = snd_usb_get_endpoint(chip, ep_num);
669 	if (ep)
670 		return 0;
671 
672 	usb_audio_dbg(chip, "Creating new %s endpoint #%x\n",
673 		      ep_type_name(type),
674 		      ep_num);
675 	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
676 	if (!ep)
677 		return -ENOMEM;
678 
679 	ep->chip = chip;
680 	spin_lock_init(&ep->lock);
681 	ep->type = type;
682 	ep->ep_num = ep_num;
683 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
684 	atomic_set(&ep->submitted_urbs, 0);
685 
686 	is_playback = ((ep_num & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT);
687 	ep_num &= USB_ENDPOINT_NUMBER_MASK;
688 	if (is_playback)
689 		ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
690 	else
691 		ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
692 
693 	list_add_tail(&ep->list, &chip->ep_list);
694 	return 0;
695 }
696 
697 /* Set up syncinterval and maxsyncsize for a sync EP */
698 static void endpoint_set_syncinterval(struct snd_usb_audio *chip,
699 				      struct snd_usb_endpoint *ep)
700 {
701 	struct usb_host_interface *alts;
702 	struct usb_endpoint_descriptor *desc;
703 
704 	alts = snd_usb_get_host_interface(chip, ep->iface, ep->altsetting);
705 	if (!alts)
706 		return;
707 
708 	desc = get_endpoint(alts, ep->ep_idx);
709 	if (desc->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
710 	    desc->bRefresh >= 1 && desc->bRefresh <= 9)
711 		ep->syncinterval = desc->bRefresh;
712 	else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
713 		ep->syncinterval = 1;
714 	else if (desc->bInterval >= 1 && desc->bInterval <= 16)
715 		ep->syncinterval = desc->bInterval - 1;
716 	else
717 		ep->syncinterval = 3;
718 
719 	ep->syncmaxsize = le16_to_cpu(desc->wMaxPacketSize);
720 }
721 
722 static bool endpoint_compatible(struct snd_usb_endpoint *ep,
723 				const struct audioformat *fp,
724 				const struct snd_pcm_hw_params *params)
725 {
726 	if (!ep->opened)
727 		return false;
728 	if (ep->cur_audiofmt != fp)
729 		return false;
730 	if (ep->cur_rate != params_rate(params) ||
731 	    ep->cur_format != params_format(params) ||
732 	    ep->cur_period_frames != params_period_size(params) ||
733 	    ep->cur_buffer_periods != params_periods(params))
734 		return false;
735 	return true;
736 }
737 
738 /*
739  * Check whether the given fp and hw params are compatible with the current
740  * setup of the target EP for implicit feedback sync
741  */
742 bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip,
743 				 struct snd_usb_endpoint *ep,
744 				 const struct audioformat *fp,
745 				 const struct snd_pcm_hw_params *params)
746 {
747 	bool ret;
748 
749 	mutex_lock(&chip->mutex);
750 	ret = endpoint_compatible(ep, fp, params);
751 	mutex_unlock(&chip->mutex);
752 	return ret;
753 }
754 
755 /*
756  * snd_usb_endpoint_open: Open the endpoint
757  *
758  * Called from hw_params to assign the endpoint to the substream.
759  * It's reference-counted, and only the first opener is allowed to set up
760  * arbitrary parameters.  The later opener must be compatible with the
761  * former opened parameters.
762  * The endpoint needs to be closed via snd_usb_endpoint_close() later.
763  *
764  * Note that this function doesn't configure the endpoint.  The substream
765  * needs to set it up later via snd_usb_endpoint_set_params() and
766  * snd_usb_endpoint_prepare().
767  */
768 struct snd_usb_endpoint *
769 snd_usb_endpoint_open(struct snd_usb_audio *chip,
770 		      const struct audioformat *fp,
771 		      const struct snd_pcm_hw_params *params,
772 		      bool is_sync_ep)
773 {
774 	struct snd_usb_endpoint *ep;
775 	int ep_num = is_sync_ep ? fp->sync_ep : fp->endpoint;
776 
777 	mutex_lock(&chip->mutex);
778 	ep = snd_usb_get_endpoint(chip, ep_num);
779 	if (!ep) {
780 		usb_audio_err(chip, "Cannot find EP 0x%x to open\n", ep_num);
781 		goto unlock;
782 	}
783 
784 	if (!ep->opened) {
785 		if (is_sync_ep) {
786 			ep->iface = fp->sync_iface;
787 			ep->altsetting = fp->sync_altsetting;
788 			ep->ep_idx = fp->sync_ep_idx;
789 		} else {
790 			ep->iface = fp->iface;
791 			ep->altsetting = fp->altsetting;
792 			ep->ep_idx = fp->ep_idx;
793 		}
794 		usb_audio_dbg(chip, "Open EP 0x%x, iface=%d:%d, idx=%d\n",
795 			      ep_num, ep->iface, ep->altsetting, ep->ep_idx);
796 
797 		ep->iface_ref = iface_ref_find(chip, ep->iface);
798 		if (!ep->iface_ref) {
799 			ep = NULL;
800 			goto unlock;
801 		}
802 
803 		if (fp->protocol != UAC_VERSION_1) {
804 			ep->clock_ref = clock_ref_find(chip, fp->clock);
805 			if (!ep->clock_ref) {
806 				ep = NULL;
807 				goto unlock;
808 			}
809 			ep->clock_ref->opened++;
810 		}
811 
812 		ep->cur_audiofmt = fp;
813 		ep->cur_channels = fp->channels;
814 		ep->cur_rate = params_rate(params);
815 		ep->cur_format = params_format(params);
816 		ep->cur_frame_bytes = snd_pcm_format_physical_width(ep->cur_format) *
817 			ep->cur_channels / 8;
818 		ep->cur_period_frames = params_period_size(params);
819 		ep->cur_period_bytes = ep->cur_period_frames * ep->cur_frame_bytes;
820 		ep->cur_buffer_periods = params_periods(params);
821 
822 		if (ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
823 			endpoint_set_syncinterval(chip, ep);
824 
825 		ep->implicit_fb_sync = fp->implicit_fb;
826 		ep->need_setup = true;
827 		ep->need_prepare = true;
828 
829 		usb_audio_dbg(chip, "  channels=%d, rate=%d, format=%s, period_bytes=%d, periods=%d, implicit_fb=%d\n",
830 			      ep->cur_channels, ep->cur_rate,
831 			      snd_pcm_format_name(ep->cur_format),
832 			      ep->cur_period_bytes, ep->cur_buffer_periods,
833 			      ep->implicit_fb_sync);
834 
835 	} else {
836 		if (WARN_ON(!ep->iface_ref)) {
837 			ep = NULL;
838 			goto unlock;
839 		}
840 
841 		if (!endpoint_compatible(ep, fp, params)) {
842 			usb_audio_err(chip, "Incompatible EP setup for 0x%x\n",
843 				      ep_num);
844 			ep = NULL;
845 			goto unlock;
846 		}
847 
848 		usb_audio_dbg(chip, "Reopened EP 0x%x (count %d)\n",
849 			      ep_num, ep->opened);
850 	}
851 
852 	if (!ep->iface_ref->opened++)
853 		ep->iface_ref->need_setup = true;
854 
855 	ep->opened++;
856 
857  unlock:
858 	mutex_unlock(&chip->mutex);
859 	return ep;
860 }
861 
862 /*
863  * snd_usb_endpoint_set_sync: Link data and sync endpoints
864  *
865  * Pass NULL to sync_ep to unlink again
866  */
867 void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
868 			       struct snd_usb_endpoint *data_ep,
869 			       struct snd_usb_endpoint *sync_ep)
870 {
871 	data_ep->sync_source = sync_ep;
872 }
873 
874 /*
875  * Set data endpoint callbacks and the assigned data stream
876  *
877  * Called at PCM trigger and cleanups.
878  * Pass NULL to deactivate each callback.
879  */
880 void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
881 				   int (*prepare)(struct snd_usb_substream *subs,
882 						  struct urb *urb,
883 						  bool in_stream_lock),
884 				   void (*retire)(struct snd_usb_substream *subs,
885 						  struct urb *urb),
886 				   struct snd_usb_substream *data_subs)
887 {
888 	ep->prepare_data_urb = prepare;
889 	ep->retire_data_urb = retire;
890 	if (data_subs)
891 		ep->lowlatency_playback = data_subs->lowlatency_playback;
892 	else
893 		ep->lowlatency_playback = false;
894 	WRITE_ONCE(ep->data_subs, data_subs);
895 }
896 
897 static int endpoint_set_interface(struct snd_usb_audio *chip,
898 				  struct snd_usb_endpoint *ep,
899 				  bool set)
900 {
901 	int altset = set ? ep->altsetting : 0;
902 	int err;
903 
904 	if (ep->iface_ref->altset == altset)
905 		return 0;
906 
907 	usb_audio_dbg(chip, "Setting usb interface %d:%d for EP 0x%x\n",
908 		      ep->iface, altset, ep->ep_num);
909 	err = usb_set_interface(chip->dev, ep->iface, altset);
910 	if (err < 0) {
911 		usb_audio_err(chip, "%d:%d: usb_set_interface failed (%d)\n",
912 			      ep->iface, altset, err);
913 		return err;
914 	}
915 
916 	if (chip->quirk_flags & QUIRK_FLAG_IFACE_DELAY)
917 		msleep(50);
918 	ep->iface_ref->altset = altset;
919 	return 0;
920 }
921 
922 /*
923  * snd_usb_endpoint_close: Close the endpoint
924  *
925  * Unreference the already opened endpoint via snd_usb_endpoint_open().
926  */
927 void snd_usb_endpoint_close(struct snd_usb_audio *chip,
928 			    struct snd_usb_endpoint *ep)
929 {
930 	mutex_lock(&chip->mutex);
931 	usb_audio_dbg(chip, "Closing EP 0x%x (count %d)\n",
932 		      ep->ep_num, ep->opened);
933 
934 	if (!--ep->iface_ref->opened &&
935 		!(chip->quirk_flags & QUIRK_FLAG_IFACE_SKIP_CLOSE))
936 		endpoint_set_interface(chip, ep, false);
937 
938 	if (!--ep->opened) {
939 		if (ep->clock_ref) {
940 			if (!--ep->clock_ref->opened)
941 				ep->clock_ref->rate = 0;
942 		}
943 		ep->iface = 0;
944 		ep->altsetting = 0;
945 		ep->cur_audiofmt = NULL;
946 		ep->cur_rate = 0;
947 		ep->iface_ref = NULL;
948 		ep->clock_ref = NULL;
949 		usb_audio_dbg(chip, "EP 0x%x closed\n", ep->ep_num);
950 	}
951 	mutex_unlock(&chip->mutex);
952 }
953 
954 /* Prepare for suspening EP, called from the main suspend handler */
955 void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep)
956 {
957 	ep->need_prepare = true;
958 	if (ep->iface_ref)
959 		ep->iface_ref->need_setup = true;
960 	if (ep->clock_ref)
961 		ep->clock_ref->rate = 0;
962 }
963 
964 /*
965  *  wait until all urbs are processed.
966  */
967 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
968 {
969 	unsigned long end_time = jiffies + msecs_to_jiffies(1000);
970 	int alive;
971 
972 	if (atomic_read(&ep->state) != EP_STATE_STOPPING)
973 		return 0;
974 
975 	do {
976 		alive = atomic_read(&ep->submitted_urbs);
977 		if (!alive)
978 			break;
979 
980 		schedule_timeout_uninterruptible(1);
981 	} while (time_before(jiffies, end_time));
982 
983 	if (alive)
984 		usb_audio_err(ep->chip,
985 			"timeout: still %d active urbs on EP #%x\n",
986 			alive, ep->ep_num);
987 
988 	if (ep_state_update(ep, EP_STATE_STOPPING, EP_STATE_STOPPED)) {
989 		ep->sync_sink = NULL;
990 		snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
991 	}
992 
993 	return 0;
994 }
995 
996 /* sync the pending stop operation;
997  * this function itself doesn't trigger the stop operation
998  */
999 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
1000 {
1001 	if (ep)
1002 		wait_clear_urbs(ep);
1003 }
1004 
1005 /*
1006  * Stop active urbs
1007  *
1008  * This function moves the EP to STOPPING state if it's being RUNNING.
1009  */
1010 static int stop_urbs(struct snd_usb_endpoint *ep, bool force, bool keep_pending)
1011 {
1012 	unsigned int i;
1013 	unsigned long flags;
1014 
1015 	if (!force && atomic_read(&ep->running))
1016 		return -EBUSY;
1017 
1018 	if (!ep_state_update(ep, EP_STATE_RUNNING, EP_STATE_STOPPING))
1019 		return 0;
1020 
1021 	spin_lock_irqsave(&ep->lock, flags);
1022 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
1023 	ep->next_packet_head = 0;
1024 	ep->next_packet_queued = 0;
1025 	spin_unlock_irqrestore(&ep->lock, flags);
1026 
1027 	if (keep_pending)
1028 		return 0;
1029 
1030 	for (i = 0; i < ep->nurbs; i++) {
1031 		if (test_bit(i, &ep->active_mask)) {
1032 			if (!test_and_set_bit(i, &ep->unlink_mask)) {
1033 				struct urb *u = ep->urb[i].urb;
1034 				usb_unlink_urb(u);
1035 			}
1036 		}
1037 	}
1038 
1039 	return 0;
1040 }
1041 
1042 /*
1043  * release an endpoint's urbs
1044  */
1045 static int release_urbs(struct snd_usb_endpoint *ep, bool force)
1046 {
1047 	int i, err;
1048 
1049 	/* route incoming urbs to nirvana */
1050 	snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
1051 
1052 	/* stop and unlink urbs */
1053 	err = stop_urbs(ep, force, false);
1054 	if (err)
1055 		return err;
1056 
1057 	wait_clear_urbs(ep);
1058 
1059 	for (i = 0; i < ep->nurbs; i++)
1060 		release_urb_ctx(&ep->urb[i]);
1061 
1062 	usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
1063 			  ep->syncbuf, ep->sync_dma);
1064 
1065 	ep->syncbuf = NULL;
1066 	ep->nurbs = 0;
1067 	return 0;
1068 }
1069 
1070 /*
1071  * configure a data endpoint
1072  */
1073 static int data_ep_set_params(struct snd_usb_endpoint *ep)
1074 {
1075 	struct snd_usb_audio *chip = ep->chip;
1076 	unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
1077 	unsigned int max_packs_per_period, urbs_per_period, urb_packs;
1078 	unsigned int max_urbs, i;
1079 	const struct audioformat *fmt = ep->cur_audiofmt;
1080 	int frame_bits = ep->cur_frame_bytes * 8;
1081 	int tx_length_quirk = (has_tx_length_quirk(chip) &&
1082 			       usb_pipeout(ep->pipe));
1083 
1084 	usb_audio_dbg(chip, "Setting params for data EP 0x%x, pipe 0x%x\n",
1085 		      ep->ep_num, ep->pipe);
1086 
1087 	if (ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
1088 		/*
1089 		 * When operating in DSD DOP mode, the size of a sample frame
1090 		 * in hardware differs from the actual physical format width
1091 		 * because we need to make room for the DOP markers.
1092 		 */
1093 		frame_bits += ep->cur_channels << 3;
1094 	}
1095 
1096 	ep->datainterval = fmt->datainterval;
1097 	ep->stride = frame_bits >> 3;
1098 
1099 	switch (ep->cur_format) {
1100 	case SNDRV_PCM_FORMAT_U8:
1101 		ep->silence_value = 0x80;
1102 		break;
1103 	case SNDRV_PCM_FORMAT_DSD_U8:
1104 	case SNDRV_PCM_FORMAT_DSD_U16_LE:
1105 	case SNDRV_PCM_FORMAT_DSD_U32_LE:
1106 	case SNDRV_PCM_FORMAT_DSD_U16_BE:
1107 	case SNDRV_PCM_FORMAT_DSD_U32_BE:
1108 		ep->silence_value = 0x69;
1109 		break;
1110 	default:
1111 		ep->silence_value = 0;
1112 	}
1113 
1114 	/* assume max. frequency is 50% higher than nominal */
1115 	ep->freqmax = ep->freqn + (ep->freqn >> 1);
1116 	/* Round up freqmax to nearest integer in order to calculate maximum
1117 	 * packet size, which must represent a whole number of frames.
1118 	 * This is accomplished by adding 0x0.ffff before converting the
1119 	 * Q16.16 format into integer.
1120 	 * In order to accurately calculate the maximum packet size when
1121 	 * the data interval is more than 1 (i.e. ep->datainterval > 0),
1122 	 * multiply by the data interval prior to rounding. For instance,
1123 	 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
1124 	 * frames with a data interval of 1, but 11 (10.25) frames with a
1125 	 * data interval of 2.
1126 	 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
1127 	 * maximum datainterval value of 3, at USB full speed, higher for
1128 	 * USB high speed, noting that ep->freqmax is in units of
1129 	 * frames per packet in Q16.16 format.)
1130 	 */
1131 	maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
1132 			 (frame_bits >> 3);
1133 	if (tx_length_quirk)
1134 		maxsize += sizeof(__le32); /* Space for length descriptor */
1135 	/* but wMaxPacketSize might reduce this */
1136 	if (ep->maxpacksize && ep->maxpacksize < maxsize) {
1137 		/* whatever fits into a max. size packet */
1138 		unsigned int data_maxsize = maxsize = ep->maxpacksize;
1139 
1140 		if (tx_length_quirk)
1141 			/* Need to remove the length descriptor to calc freq */
1142 			data_maxsize -= sizeof(__le32);
1143 		ep->freqmax = (data_maxsize / (frame_bits >> 3))
1144 				<< (16 - ep->datainterval);
1145 	}
1146 
1147 	if (ep->fill_max)
1148 		ep->curpacksize = ep->maxpacksize;
1149 	else
1150 		ep->curpacksize = maxsize;
1151 
1152 	if (snd_usb_get_speed(chip->dev) != USB_SPEED_FULL) {
1153 		packs_per_ms = 8 >> ep->datainterval;
1154 		max_packs_per_urb = MAX_PACKS_HS;
1155 	} else {
1156 		packs_per_ms = 1;
1157 		max_packs_per_urb = MAX_PACKS;
1158 	}
1159 	if (ep->sync_source && !ep->implicit_fb_sync)
1160 		max_packs_per_urb = min(max_packs_per_urb,
1161 					1U << ep->sync_source->syncinterval);
1162 	max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
1163 
1164 	/*
1165 	 * Capture endpoints need to use small URBs because there's no way
1166 	 * to tell in advance where the next period will end, and we don't
1167 	 * want the next URB to complete much after the period ends.
1168 	 *
1169 	 * Playback endpoints with implicit sync much use the same parameters
1170 	 * as their corresponding capture endpoint.
1171 	 */
1172 	if (usb_pipein(ep->pipe) || ep->implicit_fb_sync) {
1173 
1174 		urb_packs = packs_per_ms;
1175 		/*
1176 		 * Wireless devices can poll at a max rate of once per 4ms.
1177 		 * For dataintervals less than 5, increase the packet count to
1178 		 * allow the host controller to use bursting to fill in the
1179 		 * gaps.
1180 		 */
1181 		if (snd_usb_get_speed(chip->dev) == USB_SPEED_WIRELESS) {
1182 			int interval = ep->datainterval;
1183 			while (interval < 5) {
1184 				urb_packs <<= 1;
1185 				++interval;
1186 			}
1187 		}
1188 		/* make capture URBs <= 1 ms and smaller than a period */
1189 		urb_packs = min(max_packs_per_urb, urb_packs);
1190 		while (urb_packs > 1 && urb_packs * maxsize >= ep->cur_period_bytes)
1191 			urb_packs >>= 1;
1192 		ep->nurbs = MAX_URBS;
1193 
1194 	/*
1195 	 * Playback endpoints without implicit sync are adjusted so that
1196 	 * a period fits as evenly as possible in the smallest number of
1197 	 * URBs.  The total number of URBs is adjusted to the size of the
1198 	 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
1199 	 */
1200 	} else {
1201 		/* determine how small a packet can be */
1202 		minsize = (ep->freqn >> (16 - ep->datainterval)) *
1203 				(frame_bits >> 3);
1204 		/* with sync from device, assume it can be 12% lower */
1205 		if (ep->sync_source)
1206 			minsize -= minsize >> 3;
1207 		minsize = max(minsize, 1u);
1208 
1209 		/* how many packets will contain an entire ALSA period? */
1210 		max_packs_per_period = DIV_ROUND_UP(ep->cur_period_bytes, minsize);
1211 
1212 		/* how many URBs will contain a period? */
1213 		urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
1214 				max_packs_per_urb);
1215 		/* how many packets are needed in each URB? */
1216 		urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
1217 
1218 		/* limit the number of frames in a single URB */
1219 		ep->max_urb_frames = DIV_ROUND_UP(ep->cur_period_frames,
1220 						  urbs_per_period);
1221 
1222 		/* try to use enough URBs to contain an entire ALSA buffer */
1223 		max_urbs = min((unsigned) MAX_URBS,
1224 				MAX_QUEUE * packs_per_ms / urb_packs);
1225 		ep->nurbs = min(max_urbs, urbs_per_period * ep->cur_buffer_periods);
1226 	}
1227 
1228 	/* allocate and initialize data urbs */
1229 	for (i = 0; i < ep->nurbs; i++) {
1230 		struct snd_urb_ctx *u = &ep->urb[i];
1231 		u->index = i;
1232 		u->ep = ep;
1233 		u->packets = urb_packs;
1234 		u->buffer_size = maxsize * u->packets;
1235 
1236 		if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
1237 			u->packets++; /* for transfer delimiter */
1238 		u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
1239 		if (!u->urb)
1240 			goto out_of_memory;
1241 
1242 		u->urb->transfer_buffer =
1243 			usb_alloc_coherent(chip->dev, u->buffer_size,
1244 					   GFP_KERNEL, &u->urb->transfer_dma);
1245 		if (!u->urb->transfer_buffer)
1246 			goto out_of_memory;
1247 		u->urb->pipe = ep->pipe;
1248 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1249 		u->urb->interval = 1 << ep->datainterval;
1250 		u->urb->context = u;
1251 		u->urb->complete = snd_complete_urb;
1252 		INIT_LIST_HEAD(&u->ready_list);
1253 	}
1254 
1255 	return 0;
1256 
1257 out_of_memory:
1258 	release_urbs(ep, false);
1259 	return -ENOMEM;
1260 }
1261 
1262 /*
1263  * configure a sync endpoint
1264  */
1265 static int sync_ep_set_params(struct snd_usb_endpoint *ep)
1266 {
1267 	struct snd_usb_audio *chip = ep->chip;
1268 	int i;
1269 
1270 	usb_audio_dbg(chip, "Setting params for sync EP 0x%x, pipe 0x%x\n",
1271 		      ep->ep_num, ep->pipe);
1272 
1273 	ep->syncbuf = usb_alloc_coherent(chip->dev, SYNC_URBS * 4,
1274 					 GFP_KERNEL, &ep->sync_dma);
1275 	if (!ep->syncbuf)
1276 		return -ENOMEM;
1277 
1278 	ep->nurbs = SYNC_URBS;
1279 	for (i = 0; i < SYNC_URBS; i++) {
1280 		struct snd_urb_ctx *u = &ep->urb[i];
1281 		u->index = i;
1282 		u->ep = ep;
1283 		u->packets = 1;
1284 		u->urb = usb_alloc_urb(1, GFP_KERNEL);
1285 		if (!u->urb)
1286 			goto out_of_memory;
1287 		u->urb->transfer_buffer = ep->syncbuf + i * 4;
1288 		u->urb->transfer_dma = ep->sync_dma + i * 4;
1289 		u->urb->transfer_buffer_length = 4;
1290 		u->urb->pipe = ep->pipe;
1291 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1292 		u->urb->number_of_packets = 1;
1293 		u->urb->interval = 1 << ep->syncinterval;
1294 		u->urb->context = u;
1295 		u->urb->complete = snd_complete_urb;
1296 	}
1297 
1298 	return 0;
1299 
1300 out_of_memory:
1301 	release_urbs(ep, false);
1302 	return -ENOMEM;
1303 }
1304 
1305 /* update the rate of the referred clock; return the actual rate */
1306 static int update_clock_ref_rate(struct snd_usb_audio *chip,
1307 				 struct snd_usb_endpoint *ep)
1308 {
1309 	struct snd_usb_clock_ref *clock = ep->clock_ref;
1310 	int rate = ep->cur_rate;
1311 
1312 	if (!clock || clock->rate == rate)
1313 		return rate;
1314 	if (clock->rate) {
1315 		if (atomic_read(&clock->locked))
1316 			return clock->rate;
1317 		if (clock->rate != rate) {
1318 			usb_audio_err(chip, "Mismatched sample rate %d vs %d for EP 0x%x\n",
1319 				      clock->rate, rate, ep->ep_num);
1320 			return clock->rate;
1321 		}
1322 	}
1323 	clock->rate = rate;
1324 	clock->need_setup = true;
1325 	return rate;
1326 }
1327 
1328 /*
1329  * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
1330  *
1331  * It's called either from hw_params callback.
1332  * Determine the number of URBs to be used on this endpoint.
1333  * An endpoint must be configured before it can be started.
1334  * An endpoint that is already running can not be reconfigured.
1335  */
1336 int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
1337 				struct snd_usb_endpoint *ep)
1338 {
1339 	const struct audioformat *fmt = ep->cur_audiofmt;
1340 	int err = 0;
1341 
1342 	mutex_lock(&chip->mutex);
1343 	if (!ep->need_setup)
1344 		goto unlock;
1345 
1346 	/* release old buffers, if any */
1347 	err = release_urbs(ep, false);
1348 	if (err < 0)
1349 		goto unlock;
1350 
1351 	ep->datainterval = fmt->datainterval;
1352 	ep->maxpacksize = fmt->maxpacksize;
1353 	ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
1354 
1355 	if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) {
1356 		ep->freqn = get_usb_full_speed_rate(ep->cur_rate);
1357 		ep->pps = 1000 >> ep->datainterval;
1358 	} else {
1359 		ep->freqn = get_usb_high_speed_rate(ep->cur_rate);
1360 		ep->pps = 8000 >> ep->datainterval;
1361 	}
1362 
1363 	ep->sample_rem = ep->cur_rate % ep->pps;
1364 	ep->packsize[0] = ep->cur_rate / ep->pps;
1365 	ep->packsize[1] = (ep->cur_rate + (ep->pps - 1)) / ep->pps;
1366 
1367 	/* calculate the frequency in 16.16 format */
1368 	ep->freqm = ep->freqn;
1369 	ep->freqshift = INT_MIN;
1370 
1371 	ep->phase = 0;
1372 
1373 	switch (ep->type) {
1374 	case  SND_USB_ENDPOINT_TYPE_DATA:
1375 		err = data_ep_set_params(ep);
1376 		break;
1377 	case  SND_USB_ENDPOINT_TYPE_SYNC:
1378 		err = sync_ep_set_params(ep);
1379 		break;
1380 	default:
1381 		err = -EINVAL;
1382 	}
1383 
1384 	usb_audio_dbg(chip, "Set up %d URBS, ret=%d\n", ep->nurbs, err);
1385 
1386 	if (err < 0)
1387 		goto unlock;
1388 
1389 	/* some unit conversions in runtime */
1390 	ep->maxframesize = ep->maxpacksize / ep->cur_frame_bytes;
1391 	ep->curframesize = ep->curpacksize / ep->cur_frame_bytes;
1392 
1393 	err = update_clock_ref_rate(chip, ep);
1394 	if (err >= 0) {
1395 		ep->need_setup = false;
1396 		err = 0;
1397 	}
1398 
1399  unlock:
1400 	mutex_unlock(&chip->mutex);
1401 	return err;
1402 }
1403 
1404 static int init_sample_rate(struct snd_usb_audio *chip,
1405 			    struct snd_usb_endpoint *ep)
1406 {
1407 	struct snd_usb_clock_ref *clock = ep->clock_ref;
1408 	int rate, err;
1409 
1410 	rate = update_clock_ref_rate(chip, ep);
1411 	if (rate < 0)
1412 		return rate;
1413 	if (clock && !clock->need_setup)
1414 		return 0;
1415 
1416 	err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, rate);
1417 	if (err < 0) {
1418 		if (clock)
1419 			clock->rate = 0; /* reset rate */
1420 		return err;
1421 	}
1422 
1423 	if (clock)
1424 		clock->need_setup = false;
1425 	return 0;
1426 }
1427 
1428 /*
1429  * snd_usb_endpoint_prepare: Prepare the endpoint
1430  *
1431  * This function sets up the EP to be fully usable state.
1432  * It's called either from prepare callback.
1433  * The function checks need_setup flag, and performs nothing unless needed,
1434  * so it's safe to call this multiple times.
1435  *
1436  * This returns zero if unchanged, 1 if the configuration has changed,
1437  * or a negative error code.
1438  */
1439 int snd_usb_endpoint_prepare(struct snd_usb_audio *chip,
1440 			     struct snd_usb_endpoint *ep)
1441 {
1442 	bool iface_first;
1443 	int err = 0;
1444 
1445 	mutex_lock(&chip->mutex);
1446 	if (WARN_ON(!ep->iface_ref))
1447 		goto unlock;
1448 	if (!ep->need_prepare)
1449 		goto unlock;
1450 
1451 	/* If the interface has been already set up, just set EP parameters */
1452 	if (!ep->iface_ref->need_setup) {
1453 		/* sample rate setup of UAC1 is per endpoint, and we need
1454 		 * to update at each EP configuration
1455 		 */
1456 		if (ep->cur_audiofmt->protocol == UAC_VERSION_1) {
1457 			err = init_sample_rate(chip, ep);
1458 			if (err < 0)
1459 				goto unlock;
1460 		}
1461 		goto done;
1462 	}
1463 
1464 	/* Need to deselect altsetting at first */
1465 	endpoint_set_interface(chip, ep, false);
1466 
1467 	/* Some UAC1 devices (e.g. Yamaha THR10) need the host interface
1468 	 * to be set up before parameter setups
1469 	 */
1470 	iface_first = ep->cur_audiofmt->protocol == UAC_VERSION_1;
1471 	/* Workaround for devices that require the interface setup at first like UAC1 */
1472 	if (chip->quirk_flags & QUIRK_FLAG_SET_IFACE_FIRST)
1473 		iface_first = true;
1474 	if (iface_first) {
1475 		err = endpoint_set_interface(chip, ep, true);
1476 		if (err < 0)
1477 			goto unlock;
1478 	}
1479 
1480 	err = snd_usb_init_pitch(chip, ep->cur_audiofmt);
1481 	if (err < 0)
1482 		goto unlock;
1483 
1484 	err = init_sample_rate(chip, ep);
1485 	if (err < 0)
1486 		goto unlock;
1487 
1488 	err = snd_usb_select_mode_quirk(chip, ep->cur_audiofmt);
1489 	if (err < 0)
1490 		goto unlock;
1491 
1492 	/* for UAC2/3, enable the interface altset here at last */
1493 	if (!iface_first) {
1494 		err = endpoint_set_interface(chip, ep, true);
1495 		if (err < 0)
1496 			goto unlock;
1497 	}
1498 
1499 	ep->iface_ref->need_setup = false;
1500 
1501  done:
1502 	ep->need_prepare = false;
1503 	err = 1;
1504 
1505 unlock:
1506 	mutex_unlock(&chip->mutex);
1507 	return err;
1508 }
1509 
1510 /* get the current rate set to the given clock by any endpoint */
1511 int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock)
1512 {
1513 	struct snd_usb_clock_ref *ref;
1514 	int rate = 0;
1515 
1516 	if (!clock)
1517 		return 0;
1518 	mutex_lock(&chip->mutex);
1519 	list_for_each_entry(ref, &chip->clock_ref_list, list) {
1520 		if (ref->clock == clock) {
1521 			rate = ref->rate;
1522 			break;
1523 		}
1524 	}
1525 	mutex_unlock(&chip->mutex);
1526 	return rate;
1527 }
1528 
1529 /**
1530  * snd_usb_endpoint_start: start an snd_usb_endpoint
1531  *
1532  * @ep: the endpoint to start
1533  *
1534  * A call to this function will increment the running count of the endpoint.
1535  * In case it is not already running, the URBs for this endpoint will be
1536  * submitted. Otherwise, this function does nothing.
1537  *
1538  * Must be balanced to calls of snd_usb_endpoint_stop().
1539  *
1540  * Returns an error if the URB submission failed, 0 in all other cases.
1541  */
1542 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
1543 {
1544 	bool is_playback = usb_pipeout(ep->pipe);
1545 	int err;
1546 	unsigned int i;
1547 
1548 	if (atomic_read(&ep->chip->shutdown))
1549 		return -EBADFD;
1550 
1551 	if (ep->sync_source)
1552 		WRITE_ONCE(ep->sync_source->sync_sink, ep);
1553 
1554 	usb_audio_dbg(ep->chip, "Starting %s EP 0x%x (running %d)\n",
1555 		      ep_type_name(ep->type), ep->ep_num,
1556 		      atomic_read(&ep->running));
1557 
1558 	/* already running? */
1559 	if (atomic_inc_return(&ep->running) != 1)
1560 		return 0;
1561 
1562 	if (ep->clock_ref)
1563 		atomic_inc(&ep->clock_ref->locked);
1564 
1565 	ep->active_mask = 0;
1566 	ep->unlink_mask = 0;
1567 	ep->phase = 0;
1568 	ep->sample_accum = 0;
1569 
1570 	snd_usb_endpoint_start_quirk(ep);
1571 
1572 	/*
1573 	 * If this endpoint has a data endpoint as implicit feedback source,
1574 	 * don't start the urbs here. Instead, mark them all as available,
1575 	 * wait for the record urbs to return and queue the playback urbs
1576 	 * from that context.
1577 	 */
1578 
1579 	if (!ep_state_update(ep, EP_STATE_STOPPED, EP_STATE_RUNNING))
1580 		goto __error;
1581 
1582 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1583 	    !(ep->chip->quirk_flags & QUIRK_FLAG_PLAYBACK_FIRST)) {
1584 		usb_audio_dbg(ep->chip, "No URB submission due to implicit fb sync\n");
1585 		i = 0;
1586 		goto fill_rest;
1587 	}
1588 
1589 	for (i = 0; i < ep->nurbs; i++) {
1590 		struct urb *urb = ep->urb[i].urb;
1591 
1592 		if (snd_BUG_ON(!urb))
1593 			goto __error;
1594 
1595 		if (is_playback)
1596 			err = prepare_outbound_urb(ep, urb->context, true);
1597 		else
1598 			err = prepare_inbound_urb(ep, urb->context);
1599 		if (err < 0) {
1600 			/* stop filling at applptr */
1601 			if (err == -EAGAIN)
1602 				break;
1603 			usb_audio_dbg(ep->chip,
1604 				      "EP 0x%x: failed to prepare urb: %d\n",
1605 				      ep->ep_num, err);
1606 			goto __error;
1607 		}
1608 
1609 		err = usb_submit_urb(urb, GFP_ATOMIC);
1610 		if (err < 0) {
1611 			usb_audio_err(ep->chip,
1612 				"cannot submit urb %d, error %d: %s\n",
1613 				i, err, usb_error_string(err));
1614 			goto __error;
1615 		}
1616 		set_bit(i, &ep->active_mask);
1617 		atomic_inc(&ep->submitted_urbs);
1618 	}
1619 
1620 	if (!i) {
1621 		usb_audio_dbg(ep->chip, "XRUN at starting EP 0x%x\n",
1622 			      ep->ep_num);
1623 		goto __error;
1624 	}
1625 
1626 	usb_audio_dbg(ep->chip, "%d URBs submitted for EP 0x%x\n",
1627 		      i, ep->ep_num);
1628 
1629  fill_rest:
1630 	/* put the remaining URBs to ready list */
1631 	if (is_playback) {
1632 		for (; i < ep->nurbs; i++)
1633 			push_back_to_ready_list(ep, ep->urb + i);
1634 	}
1635 
1636 	return 0;
1637 
1638 __error:
1639 	snd_usb_endpoint_stop(ep, false);
1640 	return -EPIPE;
1641 }
1642 
1643 /**
1644  * snd_usb_endpoint_stop: stop an snd_usb_endpoint
1645  *
1646  * @ep: the endpoint to stop (may be NULL)
1647  * @keep_pending: keep in-flight URBs
1648  *
1649  * A call to this function will decrement the running count of the endpoint.
1650  * In case the last user has requested the endpoint stop, the URBs will
1651  * actually be deactivated.
1652  *
1653  * Must be balanced to calls of snd_usb_endpoint_start().
1654  *
1655  * The caller needs to synchronize the pending stop operation via
1656  * snd_usb_endpoint_sync_pending_stop().
1657  */
1658 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending)
1659 {
1660 	if (!ep)
1661 		return;
1662 
1663 	usb_audio_dbg(ep->chip, "Stopping %s EP 0x%x (running %d)\n",
1664 		      ep_type_name(ep->type), ep->ep_num,
1665 		      atomic_read(&ep->running));
1666 
1667 	if (snd_BUG_ON(!atomic_read(&ep->running)))
1668 		return;
1669 
1670 	if (!atomic_dec_return(&ep->running)) {
1671 		if (ep->sync_source)
1672 			WRITE_ONCE(ep->sync_source->sync_sink, NULL);
1673 		stop_urbs(ep, false, keep_pending);
1674 		if (ep->clock_ref)
1675 			atomic_dec(&ep->clock_ref->locked);
1676 
1677 		if (ep->chip->quirk_flags & QUIRK_FLAG_FORCE_IFACE_RESET &&
1678 		    usb_pipeout(ep->pipe)) {
1679 			ep->need_prepare = true;
1680 			if (ep->iface_ref)
1681 				ep->iface_ref->need_setup = true;
1682 		}
1683 	}
1684 }
1685 
1686 /**
1687  * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1688  *
1689  * @ep: the endpoint to release
1690  *
1691  * This function does not care for the endpoint's running count but will tear
1692  * down all the streaming URBs immediately.
1693  */
1694 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1695 {
1696 	release_urbs(ep, true);
1697 }
1698 
1699 /**
1700  * snd_usb_endpoint_free_all: Free the resources of an snd_usb_endpoint
1701  * @chip: The chip
1702  *
1703  * This free all endpoints and those resources
1704  */
1705 void snd_usb_endpoint_free_all(struct snd_usb_audio *chip)
1706 {
1707 	struct snd_usb_endpoint *ep, *en;
1708 	struct snd_usb_iface_ref *ip, *in;
1709 	struct snd_usb_clock_ref *cp, *cn;
1710 
1711 	list_for_each_entry_safe(ep, en, &chip->ep_list, list)
1712 		kfree(ep);
1713 
1714 	list_for_each_entry_safe(ip, in, &chip->iface_ref_list, list)
1715 		kfree(ip);
1716 
1717 	list_for_each_entry_safe(cp, cn, &chip->clock_ref_list, list)
1718 		kfree(cp);
1719 }
1720 
1721 /*
1722  * snd_usb_handle_sync_urb: parse an USB sync packet
1723  *
1724  * @ep: the endpoint to handle the packet
1725  * @sender: the sending endpoint
1726  * @urb: the received packet
1727  *
1728  * This function is called from the context of an endpoint that received
1729  * the packet and is used to let another endpoint object handle the payload.
1730  */
1731 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1732 				    struct snd_usb_endpoint *sender,
1733 				    const struct urb *urb)
1734 {
1735 	int shift;
1736 	unsigned int f;
1737 	unsigned long flags;
1738 
1739 	snd_BUG_ON(ep == sender);
1740 
1741 	/*
1742 	 * In case the endpoint is operating in implicit feedback mode, prepare
1743 	 * a new outbound URB that has the same layout as the received packet
1744 	 * and add it to the list of pending urbs. queue_pending_output_urbs()
1745 	 * will take care of them later.
1746 	 */
1747 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1748 	    atomic_read(&ep->running)) {
1749 
1750 		/* implicit feedback case */
1751 		int i, bytes = 0;
1752 		struct snd_urb_ctx *in_ctx;
1753 		struct snd_usb_packet_info *out_packet;
1754 
1755 		in_ctx = urb->context;
1756 
1757 		/* Count overall packet size */
1758 		for (i = 0; i < in_ctx->packets; i++)
1759 			if (urb->iso_frame_desc[i].status == 0)
1760 				bytes += urb->iso_frame_desc[i].actual_length;
1761 
1762 		/*
1763 		 * skip empty packets. At least M-Audio's Fast Track Ultra stops
1764 		 * streaming once it received a 0-byte OUT URB
1765 		 */
1766 		if (bytes == 0)
1767 			return;
1768 
1769 		spin_lock_irqsave(&ep->lock, flags);
1770 		if (ep->next_packet_queued >= ARRAY_SIZE(ep->next_packet)) {
1771 			spin_unlock_irqrestore(&ep->lock, flags);
1772 			usb_audio_err(ep->chip,
1773 				      "next package FIFO overflow EP 0x%x\n",
1774 				      ep->ep_num);
1775 			notify_xrun(ep);
1776 			return;
1777 		}
1778 
1779 		out_packet = next_packet_fifo_enqueue(ep);
1780 
1781 		/*
1782 		 * Iterate through the inbound packet and prepare the lengths
1783 		 * for the output packet. The OUT packet we are about to send
1784 		 * will have the same amount of payload bytes per stride as the
1785 		 * IN packet we just received. Since the actual size is scaled
1786 		 * by the stride, use the sender stride to calculate the length
1787 		 * in case the number of channels differ between the implicitly
1788 		 * fed-back endpoint and the synchronizing endpoint.
1789 		 */
1790 
1791 		out_packet->packets = in_ctx->packets;
1792 		for (i = 0; i < in_ctx->packets; i++) {
1793 			if (urb->iso_frame_desc[i].status == 0)
1794 				out_packet->packet_size[i] =
1795 					urb->iso_frame_desc[i].actual_length / sender->stride;
1796 			else
1797 				out_packet->packet_size[i] = 0;
1798 		}
1799 
1800 		spin_unlock_irqrestore(&ep->lock, flags);
1801 		snd_usb_queue_pending_output_urbs(ep, false);
1802 
1803 		return;
1804 	}
1805 
1806 	/*
1807 	 * process after playback sync complete
1808 	 *
1809 	 * Full speed devices report feedback values in 10.14 format as samples
1810 	 * per frame, high speed devices in 16.16 format as samples per
1811 	 * microframe.
1812 	 *
1813 	 * Because the Audio Class 1 spec was written before USB 2.0, many high
1814 	 * speed devices use a wrong interpretation, some others use an
1815 	 * entirely different format.
1816 	 *
1817 	 * Therefore, we cannot predict what format any particular device uses
1818 	 * and must detect it automatically.
1819 	 */
1820 
1821 	if (urb->iso_frame_desc[0].status != 0 ||
1822 	    urb->iso_frame_desc[0].actual_length < 3)
1823 		return;
1824 
1825 	f = le32_to_cpup(urb->transfer_buffer);
1826 	if (urb->iso_frame_desc[0].actual_length == 3)
1827 		f &= 0x00ffffff;
1828 	else
1829 		f &= 0x0fffffff;
1830 
1831 	if (f == 0)
1832 		return;
1833 
1834 	if (unlikely(sender->tenor_fb_quirk)) {
1835 		/*
1836 		 * Devices based on Tenor 8802 chipsets (TEAC UD-H01
1837 		 * and others) sometimes change the feedback value
1838 		 * by +/- 0x1.0000.
1839 		 */
1840 		if (f < ep->freqn - 0x8000)
1841 			f += 0xf000;
1842 		else if (f > ep->freqn + 0x8000)
1843 			f -= 0xf000;
1844 	} else if (unlikely(ep->freqshift == INT_MIN)) {
1845 		/*
1846 		 * The first time we see a feedback value, determine its format
1847 		 * by shifting it left or right until it matches the nominal
1848 		 * frequency value.  This assumes that the feedback does not
1849 		 * differ from the nominal value more than +50% or -25%.
1850 		 */
1851 		shift = 0;
1852 		while (f < ep->freqn - ep->freqn / 4) {
1853 			f <<= 1;
1854 			shift++;
1855 		}
1856 		while (f > ep->freqn + ep->freqn / 2) {
1857 			f >>= 1;
1858 			shift--;
1859 		}
1860 		ep->freqshift = shift;
1861 	} else if (ep->freqshift >= 0)
1862 		f <<= ep->freqshift;
1863 	else
1864 		f >>= -ep->freqshift;
1865 
1866 	if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1867 		/*
1868 		 * If the frequency looks valid, set it.
1869 		 * This value is referred to in prepare_playback_urb().
1870 		 */
1871 		spin_lock_irqsave(&ep->lock, flags);
1872 		ep->freqm = f;
1873 		spin_unlock_irqrestore(&ep->lock, flags);
1874 	} else {
1875 		/*
1876 		 * Out of range; maybe the shift value is wrong.
1877 		 * Reset it so that we autodetect again the next time.
1878 		 */
1879 		ep->freqshift = INT_MIN;
1880 	}
1881 }
1882 
1883