xref: /linux/sound/usb/endpoint.c (revision 0e9ab8e4d44ae9d9aaf213bfd2c90bbe7289337b)
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 		      bool fixed_rate)
774 {
775 	struct snd_usb_endpoint *ep;
776 	int ep_num = is_sync_ep ? fp->sync_ep : fp->endpoint;
777 
778 	mutex_lock(&chip->mutex);
779 	ep = snd_usb_get_endpoint(chip, ep_num);
780 	if (!ep) {
781 		usb_audio_err(chip, "Cannot find EP 0x%x to open\n", ep_num);
782 		goto unlock;
783 	}
784 
785 	if (!ep->opened) {
786 		if (is_sync_ep) {
787 			ep->iface = fp->sync_iface;
788 			ep->altsetting = fp->sync_altsetting;
789 			ep->ep_idx = fp->sync_ep_idx;
790 		} else {
791 			ep->iface = fp->iface;
792 			ep->altsetting = fp->altsetting;
793 			ep->ep_idx = fp->ep_idx;
794 		}
795 		usb_audio_dbg(chip, "Open EP 0x%x, iface=%d:%d, idx=%d\n",
796 			      ep_num, ep->iface, ep->altsetting, ep->ep_idx);
797 
798 		ep->iface_ref = iface_ref_find(chip, ep->iface);
799 		if (!ep->iface_ref) {
800 			ep = NULL;
801 			goto unlock;
802 		}
803 
804 		if (fp->protocol != UAC_VERSION_1) {
805 			ep->clock_ref = clock_ref_find(chip, fp->clock);
806 			if (!ep->clock_ref) {
807 				ep = NULL;
808 				goto unlock;
809 			}
810 			ep->clock_ref->opened++;
811 		}
812 
813 		ep->cur_audiofmt = fp;
814 		ep->cur_channels = fp->channels;
815 		ep->cur_rate = params_rate(params);
816 		ep->cur_format = params_format(params);
817 		ep->cur_frame_bytes = snd_pcm_format_physical_width(ep->cur_format) *
818 			ep->cur_channels / 8;
819 		ep->cur_period_frames = params_period_size(params);
820 		ep->cur_period_bytes = ep->cur_period_frames * ep->cur_frame_bytes;
821 		ep->cur_buffer_periods = params_periods(params);
822 
823 		if (ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
824 			endpoint_set_syncinterval(chip, ep);
825 
826 		ep->implicit_fb_sync = fp->implicit_fb;
827 		ep->need_setup = true;
828 		ep->need_prepare = true;
829 		ep->fixed_rate = fixed_rate;
830 
831 		usb_audio_dbg(chip, "  channels=%d, rate=%d, format=%s, period_bytes=%d, periods=%d, implicit_fb=%d\n",
832 			      ep->cur_channels, ep->cur_rate,
833 			      snd_pcm_format_name(ep->cur_format),
834 			      ep->cur_period_bytes, ep->cur_buffer_periods,
835 			      ep->implicit_fb_sync);
836 
837 	} else {
838 		if (WARN_ON(!ep->iface_ref)) {
839 			ep = NULL;
840 			goto unlock;
841 		}
842 
843 		if (!endpoint_compatible(ep, fp, params)) {
844 			usb_audio_err(chip, "Incompatible EP setup for 0x%x\n",
845 				      ep_num);
846 			ep = NULL;
847 			goto unlock;
848 		}
849 
850 		usb_audio_dbg(chip, "Reopened EP 0x%x (count %d)\n",
851 			      ep_num, ep->opened);
852 	}
853 
854 	if (!ep->iface_ref->opened++)
855 		ep->iface_ref->need_setup = true;
856 
857 	ep->opened++;
858 
859  unlock:
860 	mutex_unlock(&chip->mutex);
861 	return ep;
862 }
863 
864 /*
865  * snd_usb_endpoint_set_sync: Link data and sync endpoints
866  *
867  * Pass NULL to sync_ep to unlink again
868  */
869 void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
870 			       struct snd_usb_endpoint *data_ep,
871 			       struct snd_usb_endpoint *sync_ep)
872 {
873 	data_ep->sync_source = sync_ep;
874 }
875 
876 /*
877  * Set data endpoint callbacks and the assigned data stream
878  *
879  * Called at PCM trigger and cleanups.
880  * Pass NULL to deactivate each callback.
881  */
882 void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
883 				   int (*prepare)(struct snd_usb_substream *subs,
884 						  struct urb *urb,
885 						  bool in_stream_lock),
886 				   void (*retire)(struct snd_usb_substream *subs,
887 						  struct urb *urb),
888 				   struct snd_usb_substream *data_subs)
889 {
890 	ep->prepare_data_urb = prepare;
891 	ep->retire_data_urb = retire;
892 	if (data_subs)
893 		ep->lowlatency_playback = data_subs->lowlatency_playback;
894 	else
895 		ep->lowlatency_playback = false;
896 	WRITE_ONCE(ep->data_subs, data_subs);
897 }
898 
899 static int endpoint_set_interface(struct snd_usb_audio *chip,
900 				  struct snd_usb_endpoint *ep,
901 				  bool set)
902 {
903 	int altset = set ? ep->altsetting : 0;
904 	int err;
905 
906 	if (ep->iface_ref->altset == altset)
907 		return 0;
908 
909 	usb_audio_dbg(chip, "Setting usb interface %d:%d for EP 0x%x\n",
910 		      ep->iface, altset, ep->ep_num);
911 	err = usb_set_interface(chip->dev, ep->iface, altset);
912 	if (err < 0) {
913 		usb_audio_err(chip, "%d:%d: usb_set_interface failed (%d)\n",
914 			      ep->iface, altset, err);
915 		return err;
916 	}
917 
918 	if (chip->quirk_flags & QUIRK_FLAG_IFACE_DELAY)
919 		msleep(50);
920 	ep->iface_ref->altset = altset;
921 	return 0;
922 }
923 
924 /*
925  * snd_usb_endpoint_close: Close the endpoint
926  *
927  * Unreference the already opened endpoint via snd_usb_endpoint_open().
928  */
929 void snd_usb_endpoint_close(struct snd_usb_audio *chip,
930 			    struct snd_usb_endpoint *ep)
931 {
932 	mutex_lock(&chip->mutex);
933 	usb_audio_dbg(chip, "Closing EP 0x%x (count %d)\n",
934 		      ep->ep_num, ep->opened);
935 
936 	if (!--ep->iface_ref->opened &&
937 		!(chip->quirk_flags & QUIRK_FLAG_IFACE_SKIP_CLOSE))
938 		endpoint_set_interface(chip, ep, false);
939 
940 	if (!--ep->opened) {
941 		if (ep->clock_ref) {
942 			if (!--ep->clock_ref->opened)
943 				ep->clock_ref->rate = 0;
944 		}
945 		ep->iface = 0;
946 		ep->altsetting = 0;
947 		ep->cur_audiofmt = NULL;
948 		ep->cur_rate = 0;
949 		ep->iface_ref = NULL;
950 		ep->clock_ref = NULL;
951 		usb_audio_dbg(chip, "EP 0x%x closed\n", ep->ep_num);
952 	}
953 	mutex_unlock(&chip->mutex);
954 }
955 
956 /* Prepare for suspening EP, called from the main suspend handler */
957 void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep)
958 {
959 	ep->need_prepare = true;
960 	if (ep->iface_ref)
961 		ep->iface_ref->need_setup = true;
962 	if (ep->clock_ref)
963 		ep->clock_ref->rate = 0;
964 }
965 
966 /*
967  *  wait until all urbs are processed.
968  */
969 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
970 {
971 	unsigned long end_time = jiffies + msecs_to_jiffies(1000);
972 	int alive;
973 
974 	if (atomic_read(&ep->state) != EP_STATE_STOPPING)
975 		return 0;
976 
977 	do {
978 		alive = atomic_read(&ep->submitted_urbs);
979 		if (!alive)
980 			break;
981 
982 		schedule_timeout_uninterruptible(1);
983 	} while (time_before(jiffies, end_time));
984 
985 	if (alive)
986 		usb_audio_err(ep->chip,
987 			"timeout: still %d active urbs on EP #%x\n",
988 			alive, ep->ep_num);
989 
990 	if (ep_state_update(ep, EP_STATE_STOPPING, EP_STATE_STOPPED)) {
991 		ep->sync_sink = NULL;
992 		snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
993 	}
994 
995 	return 0;
996 }
997 
998 /* sync the pending stop operation;
999  * this function itself doesn't trigger the stop operation
1000  */
1001 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
1002 {
1003 	if (ep)
1004 		wait_clear_urbs(ep);
1005 }
1006 
1007 /*
1008  * Stop active urbs
1009  *
1010  * This function moves the EP to STOPPING state if it's being RUNNING.
1011  */
1012 static int stop_urbs(struct snd_usb_endpoint *ep, bool force, bool keep_pending)
1013 {
1014 	unsigned int i;
1015 	unsigned long flags;
1016 
1017 	if (!force && atomic_read(&ep->running))
1018 		return -EBUSY;
1019 
1020 	if (!ep_state_update(ep, EP_STATE_RUNNING, EP_STATE_STOPPING))
1021 		return 0;
1022 
1023 	spin_lock_irqsave(&ep->lock, flags);
1024 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
1025 	ep->next_packet_head = 0;
1026 	ep->next_packet_queued = 0;
1027 	spin_unlock_irqrestore(&ep->lock, flags);
1028 
1029 	if (keep_pending)
1030 		return 0;
1031 
1032 	for (i = 0; i < ep->nurbs; i++) {
1033 		if (test_bit(i, &ep->active_mask)) {
1034 			if (!test_and_set_bit(i, &ep->unlink_mask)) {
1035 				struct urb *u = ep->urb[i].urb;
1036 				usb_unlink_urb(u);
1037 			}
1038 		}
1039 	}
1040 
1041 	return 0;
1042 }
1043 
1044 /*
1045  * release an endpoint's urbs
1046  */
1047 static int release_urbs(struct snd_usb_endpoint *ep, bool force)
1048 {
1049 	int i, err;
1050 
1051 	/* route incoming urbs to nirvana */
1052 	snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
1053 
1054 	/* stop and unlink urbs */
1055 	err = stop_urbs(ep, force, false);
1056 	if (err)
1057 		return err;
1058 
1059 	wait_clear_urbs(ep);
1060 
1061 	for (i = 0; i < ep->nurbs; i++)
1062 		release_urb_ctx(&ep->urb[i]);
1063 
1064 	usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
1065 			  ep->syncbuf, ep->sync_dma);
1066 
1067 	ep->syncbuf = NULL;
1068 	ep->nurbs = 0;
1069 	return 0;
1070 }
1071 
1072 /*
1073  * configure a data endpoint
1074  */
1075 static int data_ep_set_params(struct snd_usb_endpoint *ep)
1076 {
1077 	struct snd_usb_audio *chip = ep->chip;
1078 	unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
1079 	unsigned int max_packs_per_period, urbs_per_period, urb_packs;
1080 	unsigned int max_urbs, i;
1081 	const struct audioformat *fmt = ep->cur_audiofmt;
1082 	int frame_bits = ep->cur_frame_bytes * 8;
1083 	int tx_length_quirk = (has_tx_length_quirk(chip) &&
1084 			       usb_pipeout(ep->pipe));
1085 
1086 	usb_audio_dbg(chip, "Setting params for data EP 0x%x, pipe 0x%x\n",
1087 		      ep->ep_num, ep->pipe);
1088 
1089 	if (ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
1090 		/*
1091 		 * When operating in DSD DOP mode, the size of a sample frame
1092 		 * in hardware differs from the actual physical format width
1093 		 * because we need to make room for the DOP markers.
1094 		 */
1095 		frame_bits += ep->cur_channels << 3;
1096 	}
1097 
1098 	ep->datainterval = fmt->datainterval;
1099 	ep->stride = frame_bits >> 3;
1100 
1101 	switch (ep->cur_format) {
1102 	case SNDRV_PCM_FORMAT_U8:
1103 		ep->silence_value = 0x80;
1104 		break;
1105 	case SNDRV_PCM_FORMAT_DSD_U8:
1106 	case SNDRV_PCM_FORMAT_DSD_U16_LE:
1107 	case SNDRV_PCM_FORMAT_DSD_U32_LE:
1108 	case SNDRV_PCM_FORMAT_DSD_U16_BE:
1109 	case SNDRV_PCM_FORMAT_DSD_U32_BE:
1110 		ep->silence_value = 0x69;
1111 		break;
1112 	default:
1113 		ep->silence_value = 0;
1114 	}
1115 
1116 	/* assume max. frequency is 50% higher than nominal */
1117 	ep->freqmax = ep->freqn + (ep->freqn >> 1);
1118 	/* Round up freqmax to nearest integer in order to calculate maximum
1119 	 * packet size, which must represent a whole number of frames.
1120 	 * This is accomplished by adding 0x0.ffff before converting the
1121 	 * Q16.16 format into integer.
1122 	 * In order to accurately calculate the maximum packet size when
1123 	 * the data interval is more than 1 (i.e. ep->datainterval > 0),
1124 	 * multiply by the data interval prior to rounding. For instance,
1125 	 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
1126 	 * frames with a data interval of 1, but 11 (10.25) frames with a
1127 	 * data interval of 2.
1128 	 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
1129 	 * maximum datainterval value of 3, at USB full speed, higher for
1130 	 * USB high speed, noting that ep->freqmax is in units of
1131 	 * frames per packet in Q16.16 format.)
1132 	 */
1133 	maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
1134 			 (frame_bits >> 3);
1135 	if (tx_length_quirk)
1136 		maxsize += sizeof(__le32); /* Space for length descriptor */
1137 	/* but wMaxPacketSize might reduce this */
1138 	if (ep->maxpacksize && ep->maxpacksize < maxsize) {
1139 		/* whatever fits into a max. size packet */
1140 		unsigned int data_maxsize = maxsize = ep->maxpacksize;
1141 
1142 		if (tx_length_quirk)
1143 			/* Need to remove the length descriptor to calc freq */
1144 			data_maxsize -= sizeof(__le32);
1145 		ep->freqmax = (data_maxsize / (frame_bits >> 3))
1146 				<< (16 - ep->datainterval);
1147 	}
1148 
1149 	if (ep->fill_max)
1150 		ep->curpacksize = ep->maxpacksize;
1151 	else
1152 		ep->curpacksize = maxsize;
1153 
1154 	if (snd_usb_get_speed(chip->dev) != USB_SPEED_FULL) {
1155 		packs_per_ms = 8 >> ep->datainterval;
1156 		max_packs_per_urb = MAX_PACKS_HS;
1157 	} else {
1158 		packs_per_ms = 1;
1159 		max_packs_per_urb = MAX_PACKS;
1160 	}
1161 	if (ep->sync_source && !ep->implicit_fb_sync)
1162 		max_packs_per_urb = min(max_packs_per_urb,
1163 					1U << ep->sync_source->syncinterval);
1164 	max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
1165 
1166 	/*
1167 	 * Capture endpoints need to use small URBs because there's no way
1168 	 * to tell in advance where the next period will end, and we don't
1169 	 * want the next URB to complete much after the period ends.
1170 	 *
1171 	 * Playback endpoints with implicit sync much use the same parameters
1172 	 * as their corresponding capture endpoint.
1173 	 */
1174 	if (usb_pipein(ep->pipe) || ep->implicit_fb_sync) {
1175 
1176 		urb_packs = packs_per_ms;
1177 		/*
1178 		 * Wireless devices can poll at a max rate of once per 4ms.
1179 		 * For dataintervals less than 5, increase the packet count to
1180 		 * allow the host controller to use bursting to fill in the
1181 		 * gaps.
1182 		 */
1183 		if (snd_usb_get_speed(chip->dev) == USB_SPEED_WIRELESS) {
1184 			int interval = ep->datainterval;
1185 			while (interval < 5) {
1186 				urb_packs <<= 1;
1187 				++interval;
1188 			}
1189 		}
1190 		/* make capture URBs <= 1 ms and smaller than a period */
1191 		urb_packs = min(max_packs_per_urb, urb_packs);
1192 		while (urb_packs > 1 && urb_packs * maxsize >= ep->cur_period_bytes)
1193 			urb_packs >>= 1;
1194 		ep->nurbs = MAX_URBS;
1195 
1196 	/*
1197 	 * Playback endpoints without implicit sync are adjusted so that
1198 	 * a period fits as evenly as possible in the smallest number of
1199 	 * URBs.  The total number of URBs is adjusted to the size of the
1200 	 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
1201 	 */
1202 	} else {
1203 		/* determine how small a packet can be */
1204 		minsize = (ep->freqn >> (16 - ep->datainterval)) *
1205 				(frame_bits >> 3);
1206 		/* with sync from device, assume it can be 12% lower */
1207 		if (ep->sync_source)
1208 			minsize -= minsize >> 3;
1209 		minsize = max(minsize, 1u);
1210 
1211 		/* how many packets will contain an entire ALSA period? */
1212 		max_packs_per_period = DIV_ROUND_UP(ep->cur_period_bytes, minsize);
1213 
1214 		/* how many URBs will contain a period? */
1215 		urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
1216 				max_packs_per_urb);
1217 		/* how many packets are needed in each URB? */
1218 		urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
1219 
1220 		/* limit the number of frames in a single URB */
1221 		ep->max_urb_frames = DIV_ROUND_UP(ep->cur_period_frames,
1222 						  urbs_per_period);
1223 
1224 		/* try to use enough URBs to contain an entire ALSA buffer */
1225 		max_urbs = min((unsigned) MAX_URBS,
1226 				MAX_QUEUE * packs_per_ms / urb_packs);
1227 		ep->nurbs = min(max_urbs, urbs_per_period * ep->cur_buffer_periods);
1228 	}
1229 
1230 	/* allocate and initialize data urbs */
1231 	for (i = 0; i < ep->nurbs; i++) {
1232 		struct snd_urb_ctx *u = &ep->urb[i];
1233 		u->index = i;
1234 		u->ep = ep;
1235 		u->packets = urb_packs;
1236 		u->buffer_size = maxsize * u->packets;
1237 
1238 		if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
1239 			u->packets++; /* for transfer delimiter */
1240 		u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
1241 		if (!u->urb)
1242 			goto out_of_memory;
1243 
1244 		u->urb->transfer_buffer =
1245 			usb_alloc_coherent(chip->dev, u->buffer_size,
1246 					   GFP_KERNEL, &u->urb->transfer_dma);
1247 		if (!u->urb->transfer_buffer)
1248 			goto out_of_memory;
1249 		u->urb->pipe = ep->pipe;
1250 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1251 		u->urb->interval = 1 << ep->datainterval;
1252 		u->urb->context = u;
1253 		u->urb->complete = snd_complete_urb;
1254 		INIT_LIST_HEAD(&u->ready_list);
1255 	}
1256 
1257 	return 0;
1258 
1259 out_of_memory:
1260 	release_urbs(ep, false);
1261 	return -ENOMEM;
1262 }
1263 
1264 /*
1265  * configure a sync endpoint
1266  */
1267 static int sync_ep_set_params(struct snd_usb_endpoint *ep)
1268 {
1269 	struct snd_usb_audio *chip = ep->chip;
1270 	int i;
1271 
1272 	usb_audio_dbg(chip, "Setting params for sync EP 0x%x, pipe 0x%x\n",
1273 		      ep->ep_num, ep->pipe);
1274 
1275 	ep->syncbuf = usb_alloc_coherent(chip->dev, SYNC_URBS * 4,
1276 					 GFP_KERNEL, &ep->sync_dma);
1277 	if (!ep->syncbuf)
1278 		return -ENOMEM;
1279 
1280 	ep->nurbs = SYNC_URBS;
1281 	for (i = 0; i < SYNC_URBS; i++) {
1282 		struct snd_urb_ctx *u = &ep->urb[i];
1283 		u->index = i;
1284 		u->ep = ep;
1285 		u->packets = 1;
1286 		u->urb = usb_alloc_urb(1, GFP_KERNEL);
1287 		if (!u->urb)
1288 			goto out_of_memory;
1289 		u->urb->transfer_buffer = ep->syncbuf + i * 4;
1290 		u->urb->transfer_dma = ep->sync_dma + i * 4;
1291 		u->urb->transfer_buffer_length = 4;
1292 		u->urb->pipe = ep->pipe;
1293 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1294 		u->urb->number_of_packets = 1;
1295 		u->urb->interval = 1 << ep->syncinterval;
1296 		u->urb->context = u;
1297 		u->urb->complete = snd_complete_urb;
1298 	}
1299 
1300 	return 0;
1301 
1302 out_of_memory:
1303 	release_urbs(ep, false);
1304 	return -ENOMEM;
1305 }
1306 
1307 /* update the rate of the referred clock; return the actual rate */
1308 static int update_clock_ref_rate(struct snd_usb_audio *chip,
1309 				 struct snd_usb_endpoint *ep)
1310 {
1311 	struct snd_usb_clock_ref *clock = ep->clock_ref;
1312 	int rate = ep->cur_rate;
1313 
1314 	if (!clock || clock->rate == rate)
1315 		return rate;
1316 	if (clock->rate) {
1317 		if (atomic_read(&clock->locked))
1318 			return clock->rate;
1319 		if (clock->rate != rate) {
1320 			usb_audio_err(chip, "Mismatched sample rate %d vs %d for EP 0x%x\n",
1321 				      clock->rate, rate, ep->ep_num);
1322 			return clock->rate;
1323 		}
1324 	}
1325 	clock->rate = rate;
1326 	clock->need_setup = true;
1327 	return rate;
1328 }
1329 
1330 /*
1331  * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
1332  *
1333  * It's called either from hw_params callback.
1334  * Determine the number of URBs to be used on this endpoint.
1335  * An endpoint must be configured before it can be started.
1336  * An endpoint that is already running can not be reconfigured.
1337  */
1338 int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
1339 				struct snd_usb_endpoint *ep)
1340 {
1341 	const struct audioformat *fmt = ep->cur_audiofmt;
1342 	int err = 0;
1343 
1344 	mutex_lock(&chip->mutex);
1345 	if (!ep->need_setup)
1346 		goto unlock;
1347 
1348 	/* release old buffers, if any */
1349 	err = release_urbs(ep, false);
1350 	if (err < 0)
1351 		goto unlock;
1352 
1353 	ep->datainterval = fmt->datainterval;
1354 	ep->maxpacksize = fmt->maxpacksize;
1355 	ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
1356 
1357 	if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) {
1358 		ep->freqn = get_usb_full_speed_rate(ep->cur_rate);
1359 		ep->pps = 1000 >> ep->datainterval;
1360 	} else {
1361 		ep->freqn = get_usb_high_speed_rate(ep->cur_rate);
1362 		ep->pps = 8000 >> ep->datainterval;
1363 	}
1364 
1365 	ep->sample_rem = ep->cur_rate % ep->pps;
1366 	ep->packsize[0] = ep->cur_rate / ep->pps;
1367 	ep->packsize[1] = (ep->cur_rate + (ep->pps - 1)) / ep->pps;
1368 
1369 	/* calculate the frequency in 16.16 format */
1370 	ep->freqm = ep->freqn;
1371 	ep->freqshift = INT_MIN;
1372 
1373 	ep->phase = 0;
1374 
1375 	switch (ep->type) {
1376 	case  SND_USB_ENDPOINT_TYPE_DATA:
1377 		err = data_ep_set_params(ep);
1378 		break;
1379 	case  SND_USB_ENDPOINT_TYPE_SYNC:
1380 		err = sync_ep_set_params(ep);
1381 		break;
1382 	default:
1383 		err = -EINVAL;
1384 	}
1385 
1386 	usb_audio_dbg(chip, "Set up %d URBS, ret=%d\n", ep->nurbs, err);
1387 
1388 	if (err < 0)
1389 		goto unlock;
1390 
1391 	/* some unit conversions in runtime */
1392 	ep->maxframesize = ep->maxpacksize / ep->cur_frame_bytes;
1393 	ep->curframesize = ep->curpacksize / ep->cur_frame_bytes;
1394 
1395 	err = update_clock_ref_rate(chip, ep);
1396 	if (err >= 0) {
1397 		ep->need_setup = false;
1398 		err = 0;
1399 	}
1400 
1401  unlock:
1402 	mutex_unlock(&chip->mutex);
1403 	return err;
1404 }
1405 
1406 static int init_sample_rate(struct snd_usb_audio *chip,
1407 			    struct snd_usb_endpoint *ep)
1408 {
1409 	struct snd_usb_clock_ref *clock = ep->clock_ref;
1410 	int rate, err;
1411 
1412 	rate = update_clock_ref_rate(chip, ep);
1413 	if (rate < 0)
1414 		return rate;
1415 	if (clock && !clock->need_setup)
1416 		return 0;
1417 
1418 	if (!ep->fixed_rate) {
1419 		err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, rate);
1420 		if (err < 0) {
1421 			if (clock)
1422 				clock->rate = 0; /* reset rate */
1423 			return err;
1424 		}
1425 	}
1426 
1427 	if (clock)
1428 		clock->need_setup = false;
1429 	return 0;
1430 }
1431 
1432 /*
1433  * snd_usb_endpoint_prepare: Prepare the endpoint
1434  *
1435  * This function sets up the EP to be fully usable state.
1436  * It's called either from prepare callback.
1437  * The function checks need_setup flag, and performs nothing unless needed,
1438  * so it's safe to call this multiple times.
1439  *
1440  * This returns zero if unchanged, 1 if the configuration has changed,
1441  * or a negative error code.
1442  */
1443 int snd_usb_endpoint_prepare(struct snd_usb_audio *chip,
1444 			     struct snd_usb_endpoint *ep)
1445 {
1446 	bool iface_first;
1447 	int err = 0;
1448 
1449 	mutex_lock(&chip->mutex);
1450 	if (WARN_ON(!ep->iface_ref))
1451 		goto unlock;
1452 	if (!ep->need_prepare)
1453 		goto unlock;
1454 
1455 	/* If the interface has been already set up, just set EP parameters */
1456 	if (!ep->iface_ref->need_setup) {
1457 		/* sample rate setup of UAC1 is per endpoint, and we need
1458 		 * to update at each EP configuration
1459 		 */
1460 		if (ep->cur_audiofmt->protocol == UAC_VERSION_1) {
1461 			err = init_sample_rate(chip, ep);
1462 			if (err < 0)
1463 				goto unlock;
1464 		}
1465 		goto done;
1466 	}
1467 
1468 	/* Need to deselect altsetting at first */
1469 	endpoint_set_interface(chip, ep, false);
1470 
1471 	/* Some UAC1 devices (e.g. Yamaha THR10) need the host interface
1472 	 * to be set up before parameter setups
1473 	 */
1474 	iface_first = ep->cur_audiofmt->protocol == UAC_VERSION_1;
1475 	/* Workaround for devices that require the interface setup at first like UAC1 */
1476 	if (chip->quirk_flags & QUIRK_FLAG_SET_IFACE_FIRST)
1477 		iface_first = true;
1478 	if (iface_first) {
1479 		err = endpoint_set_interface(chip, ep, true);
1480 		if (err < 0)
1481 			goto unlock;
1482 	}
1483 
1484 	err = snd_usb_init_pitch(chip, ep->cur_audiofmt);
1485 	if (err < 0)
1486 		goto unlock;
1487 
1488 	err = init_sample_rate(chip, ep);
1489 	if (err < 0)
1490 		goto unlock;
1491 
1492 	err = snd_usb_select_mode_quirk(chip, ep->cur_audiofmt);
1493 	if (err < 0)
1494 		goto unlock;
1495 
1496 	/* for UAC2/3, enable the interface altset here at last */
1497 	if (!iface_first) {
1498 		err = endpoint_set_interface(chip, ep, true);
1499 		if (err < 0)
1500 			goto unlock;
1501 	}
1502 
1503 	ep->iface_ref->need_setup = false;
1504 
1505  done:
1506 	ep->need_prepare = false;
1507 	err = 1;
1508 
1509 unlock:
1510 	mutex_unlock(&chip->mutex);
1511 	return err;
1512 }
1513 
1514 /* get the current rate set to the given clock by any endpoint */
1515 int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock)
1516 {
1517 	struct snd_usb_clock_ref *ref;
1518 	int rate = 0;
1519 
1520 	if (!clock)
1521 		return 0;
1522 	mutex_lock(&chip->mutex);
1523 	list_for_each_entry(ref, &chip->clock_ref_list, list) {
1524 		if (ref->clock == clock) {
1525 			rate = ref->rate;
1526 			break;
1527 		}
1528 	}
1529 	mutex_unlock(&chip->mutex);
1530 	return rate;
1531 }
1532 
1533 /**
1534  * snd_usb_endpoint_start: start an snd_usb_endpoint
1535  *
1536  * @ep: the endpoint to start
1537  *
1538  * A call to this function will increment the running count of the endpoint.
1539  * In case it is not already running, the URBs for this endpoint will be
1540  * submitted. Otherwise, this function does nothing.
1541  *
1542  * Must be balanced to calls of snd_usb_endpoint_stop().
1543  *
1544  * Returns an error if the URB submission failed, 0 in all other cases.
1545  */
1546 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
1547 {
1548 	bool is_playback = usb_pipeout(ep->pipe);
1549 	int err;
1550 	unsigned int i;
1551 
1552 	if (atomic_read(&ep->chip->shutdown))
1553 		return -EBADFD;
1554 
1555 	if (ep->sync_source)
1556 		WRITE_ONCE(ep->sync_source->sync_sink, ep);
1557 
1558 	usb_audio_dbg(ep->chip, "Starting %s EP 0x%x (running %d)\n",
1559 		      ep_type_name(ep->type), ep->ep_num,
1560 		      atomic_read(&ep->running));
1561 
1562 	/* already running? */
1563 	if (atomic_inc_return(&ep->running) != 1)
1564 		return 0;
1565 
1566 	if (ep->clock_ref)
1567 		atomic_inc(&ep->clock_ref->locked);
1568 
1569 	ep->active_mask = 0;
1570 	ep->unlink_mask = 0;
1571 	ep->phase = 0;
1572 	ep->sample_accum = 0;
1573 
1574 	snd_usb_endpoint_start_quirk(ep);
1575 
1576 	/*
1577 	 * If this endpoint has a data endpoint as implicit feedback source,
1578 	 * don't start the urbs here. Instead, mark them all as available,
1579 	 * wait for the record urbs to return and queue the playback urbs
1580 	 * from that context.
1581 	 */
1582 
1583 	if (!ep_state_update(ep, EP_STATE_STOPPED, EP_STATE_RUNNING))
1584 		goto __error;
1585 
1586 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1587 	    !(ep->chip->quirk_flags & QUIRK_FLAG_PLAYBACK_FIRST)) {
1588 		usb_audio_dbg(ep->chip, "No URB submission due to implicit fb sync\n");
1589 		i = 0;
1590 		goto fill_rest;
1591 	}
1592 
1593 	for (i = 0; i < ep->nurbs; i++) {
1594 		struct urb *urb = ep->urb[i].urb;
1595 
1596 		if (snd_BUG_ON(!urb))
1597 			goto __error;
1598 
1599 		if (is_playback)
1600 			err = prepare_outbound_urb(ep, urb->context, true);
1601 		else
1602 			err = prepare_inbound_urb(ep, urb->context);
1603 		if (err < 0) {
1604 			/* stop filling at applptr */
1605 			if (err == -EAGAIN)
1606 				break;
1607 			usb_audio_dbg(ep->chip,
1608 				      "EP 0x%x: failed to prepare urb: %d\n",
1609 				      ep->ep_num, err);
1610 			goto __error;
1611 		}
1612 
1613 		err = usb_submit_urb(urb, GFP_ATOMIC);
1614 		if (err < 0) {
1615 			usb_audio_err(ep->chip,
1616 				"cannot submit urb %d, error %d: %s\n",
1617 				i, err, usb_error_string(err));
1618 			goto __error;
1619 		}
1620 		set_bit(i, &ep->active_mask);
1621 		atomic_inc(&ep->submitted_urbs);
1622 	}
1623 
1624 	if (!i) {
1625 		usb_audio_dbg(ep->chip, "XRUN at starting EP 0x%x\n",
1626 			      ep->ep_num);
1627 		goto __error;
1628 	}
1629 
1630 	usb_audio_dbg(ep->chip, "%d URBs submitted for EP 0x%x\n",
1631 		      i, ep->ep_num);
1632 
1633  fill_rest:
1634 	/* put the remaining URBs to ready list */
1635 	if (is_playback) {
1636 		for (; i < ep->nurbs; i++)
1637 			push_back_to_ready_list(ep, ep->urb + i);
1638 	}
1639 
1640 	return 0;
1641 
1642 __error:
1643 	snd_usb_endpoint_stop(ep, false);
1644 	return -EPIPE;
1645 }
1646 
1647 /**
1648  * snd_usb_endpoint_stop: stop an snd_usb_endpoint
1649  *
1650  * @ep: the endpoint to stop (may be NULL)
1651  * @keep_pending: keep in-flight URBs
1652  *
1653  * A call to this function will decrement the running count of the endpoint.
1654  * In case the last user has requested the endpoint stop, the URBs will
1655  * actually be deactivated.
1656  *
1657  * Must be balanced to calls of snd_usb_endpoint_start().
1658  *
1659  * The caller needs to synchronize the pending stop operation via
1660  * snd_usb_endpoint_sync_pending_stop().
1661  */
1662 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending)
1663 {
1664 	if (!ep)
1665 		return;
1666 
1667 	usb_audio_dbg(ep->chip, "Stopping %s EP 0x%x (running %d)\n",
1668 		      ep_type_name(ep->type), ep->ep_num,
1669 		      atomic_read(&ep->running));
1670 
1671 	if (snd_BUG_ON(!atomic_read(&ep->running)))
1672 		return;
1673 
1674 	if (!atomic_dec_return(&ep->running)) {
1675 		if (ep->sync_source)
1676 			WRITE_ONCE(ep->sync_source->sync_sink, NULL);
1677 		stop_urbs(ep, false, keep_pending);
1678 		if (ep->clock_ref)
1679 			atomic_dec(&ep->clock_ref->locked);
1680 
1681 		if (ep->chip->quirk_flags & QUIRK_FLAG_FORCE_IFACE_RESET &&
1682 		    usb_pipeout(ep->pipe)) {
1683 			ep->need_prepare = true;
1684 			if (ep->iface_ref)
1685 				ep->iface_ref->need_setup = true;
1686 		}
1687 	}
1688 }
1689 
1690 /**
1691  * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1692  *
1693  * @ep: the endpoint to release
1694  *
1695  * This function does not care for the endpoint's running count but will tear
1696  * down all the streaming URBs immediately.
1697  */
1698 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1699 {
1700 	release_urbs(ep, true);
1701 }
1702 
1703 /**
1704  * snd_usb_endpoint_free_all: Free the resources of an snd_usb_endpoint
1705  * @chip: The chip
1706  *
1707  * This free all endpoints and those resources
1708  */
1709 void snd_usb_endpoint_free_all(struct snd_usb_audio *chip)
1710 {
1711 	struct snd_usb_endpoint *ep, *en;
1712 	struct snd_usb_iface_ref *ip, *in;
1713 	struct snd_usb_clock_ref *cp, *cn;
1714 
1715 	list_for_each_entry_safe(ep, en, &chip->ep_list, list)
1716 		kfree(ep);
1717 
1718 	list_for_each_entry_safe(ip, in, &chip->iface_ref_list, list)
1719 		kfree(ip);
1720 
1721 	list_for_each_entry_safe(cp, cn, &chip->clock_ref_list, list)
1722 		kfree(cp);
1723 }
1724 
1725 /*
1726  * snd_usb_handle_sync_urb: parse an USB sync packet
1727  *
1728  * @ep: the endpoint to handle the packet
1729  * @sender: the sending endpoint
1730  * @urb: the received packet
1731  *
1732  * This function is called from the context of an endpoint that received
1733  * the packet and is used to let another endpoint object handle the payload.
1734  */
1735 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1736 				    struct snd_usb_endpoint *sender,
1737 				    const struct urb *urb)
1738 {
1739 	int shift;
1740 	unsigned int f;
1741 	unsigned long flags;
1742 
1743 	snd_BUG_ON(ep == sender);
1744 
1745 	/*
1746 	 * In case the endpoint is operating in implicit feedback mode, prepare
1747 	 * a new outbound URB that has the same layout as the received packet
1748 	 * and add it to the list of pending urbs. queue_pending_output_urbs()
1749 	 * will take care of them later.
1750 	 */
1751 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1752 	    atomic_read(&ep->running)) {
1753 
1754 		/* implicit feedback case */
1755 		int i, bytes = 0;
1756 		struct snd_urb_ctx *in_ctx;
1757 		struct snd_usb_packet_info *out_packet;
1758 
1759 		in_ctx = urb->context;
1760 
1761 		/* Count overall packet size */
1762 		for (i = 0; i < in_ctx->packets; i++)
1763 			if (urb->iso_frame_desc[i].status == 0)
1764 				bytes += urb->iso_frame_desc[i].actual_length;
1765 
1766 		/*
1767 		 * skip empty packets. At least M-Audio's Fast Track Ultra stops
1768 		 * streaming once it received a 0-byte OUT URB
1769 		 */
1770 		if (bytes == 0)
1771 			return;
1772 
1773 		spin_lock_irqsave(&ep->lock, flags);
1774 		if (ep->next_packet_queued >= ARRAY_SIZE(ep->next_packet)) {
1775 			spin_unlock_irqrestore(&ep->lock, flags);
1776 			usb_audio_err(ep->chip,
1777 				      "next package FIFO overflow EP 0x%x\n",
1778 				      ep->ep_num);
1779 			notify_xrun(ep);
1780 			return;
1781 		}
1782 
1783 		out_packet = next_packet_fifo_enqueue(ep);
1784 
1785 		/*
1786 		 * Iterate through the inbound packet and prepare the lengths
1787 		 * for the output packet. The OUT packet we are about to send
1788 		 * will have the same amount of payload bytes per stride as the
1789 		 * IN packet we just received. Since the actual size is scaled
1790 		 * by the stride, use the sender stride to calculate the length
1791 		 * in case the number of channels differ between the implicitly
1792 		 * fed-back endpoint and the synchronizing endpoint.
1793 		 */
1794 
1795 		out_packet->packets = in_ctx->packets;
1796 		for (i = 0; i < in_ctx->packets; i++) {
1797 			if (urb->iso_frame_desc[i].status == 0)
1798 				out_packet->packet_size[i] =
1799 					urb->iso_frame_desc[i].actual_length / sender->stride;
1800 			else
1801 				out_packet->packet_size[i] = 0;
1802 		}
1803 
1804 		spin_unlock_irqrestore(&ep->lock, flags);
1805 		snd_usb_queue_pending_output_urbs(ep, false);
1806 
1807 		return;
1808 	}
1809 
1810 	/*
1811 	 * process after playback sync complete
1812 	 *
1813 	 * Full speed devices report feedback values in 10.14 format as samples
1814 	 * per frame, high speed devices in 16.16 format as samples per
1815 	 * microframe.
1816 	 *
1817 	 * Because the Audio Class 1 spec was written before USB 2.0, many high
1818 	 * speed devices use a wrong interpretation, some others use an
1819 	 * entirely different format.
1820 	 *
1821 	 * Therefore, we cannot predict what format any particular device uses
1822 	 * and must detect it automatically.
1823 	 */
1824 
1825 	if (urb->iso_frame_desc[0].status != 0 ||
1826 	    urb->iso_frame_desc[0].actual_length < 3)
1827 		return;
1828 
1829 	f = le32_to_cpup(urb->transfer_buffer);
1830 	if (urb->iso_frame_desc[0].actual_length == 3)
1831 		f &= 0x00ffffff;
1832 	else
1833 		f &= 0x0fffffff;
1834 
1835 	if (f == 0)
1836 		return;
1837 
1838 	if (unlikely(sender->tenor_fb_quirk)) {
1839 		/*
1840 		 * Devices based on Tenor 8802 chipsets (TEAC UD-H01
1841 		 * and others) sometimes change the feedback value
1842 		 * by +/- 0x1.0000.
1843 		 */
1844 		if (f < ep->freqn - 0x8000)
1845 			f += 0xf000;
1846 		else if (f > ep->freqn + 0x8000)
1847 			f -= 0xf000;
1848 	} else if (unlikely(ep->freqshift == INT_MIN)) {
1849 		/*
1850 		 * The first time we see a feedback value, determine its format
1851 		 * by shifting it left or right until it matches the nominal
1852 		 * frequency value.  This assumes that the feedback does not
1853 		 * differ from the nominal value more than +50% or -25%.
1854 		 */
1855 		shift = 0;
1856 		while (f < ep->freqn - ep->freqn / 4) {
1857 			f <<= 1;
1858 			shift++;
1859 		}
1860 		while (f > ep->freqn + ep->freqn / 2) {
1861 			f >>= 1;
1862 			shift--;
1863 		}
1864 		ep->freqshift = shift;
1865 	} else if (ep->freqshift >= 0)
1866 		f <<= ep->freqshift;
1867 	else
1868 		f >>= -ep->freqshift;
1869 
1870 	if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1871 		/*
1872 		 * If the frequency looks valid, set it.
1873 		 * This value is referred to in prepare_playback_urb().
1874 		 */
1875 		spin_lock_irqsave(&ep->lock, flags);
1876 		ep->freqm = f;
1877 		spin_unlock_irqrestore(&ep->lock, flags);
1878 	} else {
1879 		/*
1880 		 * Out of range; maybe the shift value is wrong.
1881 		 * Reset it so that we autodetect again the next time.
1882 		 */
1883 		ep->freqshift = INT_MIN;
1884 	}
1885 }
1886 
1887