xref: /openbmc/linux/sound/usb/endpoint.c (revision c4e78957)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  */
4 
5 #include <linux/gfp.h>
6 #include <linux/init.h>
7 #include <linux/ratelimit.h>
8 #include <linux/usb.h>
9 #include <linux/usb/audio.h>
10 #include <linux/slab.h>
11 
12 #include <sound/core.h>
13 #include <sound/pcm.h>
14 #include <sound/pcm_params.h>
15 
16 #include "usbaudio.h"
17 #include "helper.h"
18 #include "card.h"
19 #include "endpoint.h"
20 #include "pcm.h"
21 #include "clock.h"
22 #include "quirks.h"
23 
24 enum {
25 	EP_STATE_STOPPED,
26 	EP_STATE_RUNNING,
27 	EP_STATE_STOPPING,
28 };
29 
30 /* interface refcounting */
31 struct snd_usb_iface_ref {
32 	unsigned char iface;
33 	bool need_setup;
34 	int opened;
35 	struct list_head list;
36 };
37 
38 /* clock refcounting */
39 struct snd_usb_clock_ref {
40 	unsigned char clock;
41 	atomic_t locked;
42 	int rate;
43 	struct list_head list;
44 };
45 
46 /*
47  * snd_usb_endpoint is a model that abstracts everything related to an
48  * USB endpoint and its streaming.
49  *
50  * There are functions to activate and deactivate the streaming URBs and
51  * optional callbacks to let the pcm logic handle the actual content of the
52  * packets for playback and record. Thus, the bus streaming and the audio
53  * handlers are fully decoupled.
54  *
55  * There are two different types of endpoints in audio applications.
56  *
57  * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
58  * inbound and outbound traffic.
59  *
60  * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
61  * expect the payload to carry Q10.14 / Q16.16 formatted sync information
62  * (3 or 4 bytes).
63  *
64  * Each endpoint has to be configured prior to being used by calling
65  * snd_usb_endpoint_set_params().
66  *
67  * The model incorporates a reference counting, so that multiple users
68  * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
69  * only the first user will effectively start the URBs, and only the last
70  * one to stop it will tear the URBs down again.
71  */
72 
73 /*
74  * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
75  * this will overflow at approx 524 kHz
76  */
77 static inline unsigned get_usb_full_speed_rate(unsigned int rate)
78 {
79 	return ((rate << 13) + 62) / 125;
80 }
81 
82 /*
83  * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
84  * this will overflow at approx 4 MHz
85  */
86 static inline unsigned get_usb_high_speed_rate(unsigned int rate)
87 {
88 	return ((rate << 10) + 62) / 125;
89 }
90 
91 /*
92  * release a urb data
93  */
94 static void release_urb_ctx(struct snd_urb_ctx *u)
95 {
96 	if (u->buffer_size)
97 		usb_free_coherent(u->ep->chip->dev, u->buffer_size,
98 				  u->urb->transfer_buffer,
99 				  u->urb->transfer_dma);
100 	usb_free_urb(u->urb);
101 	u->urb = NULL;
102 }
103 
104 static const char *usb_error_string(int err)
105 {
106 	switch (err) {
107 	case -ENODEV:
108 		return "no device";
109 	case -ENOENT:
110 		return "endpoint not enabled";
111 	case -EPIPE:
112 		return "endpoint stalled";
113 	case -ENOSPC:
114 		return "not enough bandwidth";
115 	case -ESHUTDOWN:
116 		return "device disabled";
117 	case -EHOSTUNREACH:
118 		return "device suspended";
119 	case -EINVAL:
120 	case -EAGAIN:
121 	case -EFBIG:
122 	case -EMSGSIZE:
123 		return "internal error";
124 	default:
125 		return "unknown error";
126 	}
127 }
128 
129 static inline bool ep_state_running(struct snd_usb_endpoint *ep)
130 {
131 	return atomic_read(&ep->state) == EP_STATE_RUNNING;
132 }
133 
134 static inline bool ep_state_update(struct snd_usb_endpoint *ep, int old, int new)
135 {
136 	return atomic_cmpxchg(&ep->state, old, new) == old;
137 }
138 
139 /**
140  * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
141  *
142  * @ep: The snd_usb_endpoint
143  *
144  * Determine whether an endpoint is driven by an implicit feedback
145  * data endpoint source.
146  */
147 int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
148 {
149 	return  ep->implicit_fb_sync && usb_pipeout(ep->pipe);
150 }
151 
152 /*
153  * Return the number of samples to be sent in the next packet
154  * for streaming based on information derived from sync endpoints
155  *
156  * This won't be used for implicit feedback which takes the packet size
157  * returned from the sync source
158  */
159 static int slave_next_packet_size(struct snd_usb_endpoint *ep,
160 				  unsigned int avail)
161 {
162 	unsigned long flags;
163 	unsigned int phase;
164 	int ret;
165 
166 	if (ep->fill_max)
167 		return ep->maxframesize;
168 
169 	spin_lock_irqsave(&ep->lock, flags);
170 	phase = (ep->phase & 0xffff) + (ep->freqm << ep->datainterval);
171 	ret = min(phase >> 16, ep->maxframesize);
172 	if (avail && ret >= avail)
173 		ret = -EAGAIN;
174 	else
175 		ep->phase = phase;
176 	spin_unlock_irqrestore(&ep->lock, flags);
177 
178 	return ret;
179 }
180 
181 /*
182  * Return the number of samples to be sent in the next packet
183  * for adaptive and synchronous endpoints
184  */
185 static int next_packet_size(struct snd_usb_endpoint *ep, unsigned int avail)
186 {
187 	unsigned int sample_accum;
188 	int ret;
189 
190 	if (ep->fill_max)
191 		return ep->maxframesize;
192 
193 	sample_accum = ep->sample_accum + ep->sample_rem;
194 	if (sample_accum >= ep->pps) {
195 		sample_accum -= ep->pps;
196 		ret = ep->packsize[1];
197 	} else {
198 		ret = ep->packsize[0];
199 	}
200 	if (avail && ret >= avail)
201 		ret = -EAGAIN;
202 	else
203 		ep->sample_accum = sample_accum;
204 
205 	return ret;
206 }
207 
208 /*
209  * snd_usb_endpoint_next_packet_size: Return the number of samples to be sent
210  * in the next packet
211  *
212  * If the size is equal or exceeds @avail, don't proceed but return -EAGAIN
213  * Exception: @avail = 0 for skipping the check.
214  */
215 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep,
216 				      struct snd_urb_ctx *ctx, int idx,
217 				      unsigned int avail)
218 {
219 	unsigned int packet;
220 
221 	packet = ctx->packet_size[idx];
222 	if (packet) {
223 		if (avail && packet >= avail)
224 			return -EAGAIN;
225 		return packet;
226 	}
227 
228 	if (ep->sync_source)
229 		return slave_next_packet_size(ep, avail);
230 	else
231 		return next_packet_size(ep, avail);
232 }
233 
234 static void call_retire_callback(struct snd_usb_endpoint *ep,
235 				 struct urb *urb)
236 {
237 	struct snd_usb_substream *data_subs;
238 
239 	data_subs = READ_ONCE(ep->data_subs);
240 	if (data_subs && ep->retire_data_urb)
241 		ep->retire_data_urb(data_subs, urb);
242 }
243 
244 static void retire_outbound_urb(struct snd_usb_endpoint *ep,
245 				struct snd_urb_ctx *urb_ctx)
246 {
247 	call_retire_callback(ep, urb_ctx->urb);
248 }
249 
250 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
251 				    struct snd_usb_endpoint *sender,
252 				    const struct urb *urb);
253 
254 static void retire_inbound_urb(struct snd_usb_endpoint *ep,
255 			       struct snd_urb_ctx *urb_ctx)
256 {
257 	struct urb *urb = urb_ctx->urb;
258 	struct snd_usb_endpoint *sync_sink;
259 
260 	if (unlikely(ep->skip_packets > 0)) {
261 		ep->skip_packets--;
262 		return;
263 	}
264 
265 	sync_sink = READ_ONCE(ep->sync_sink);
266 	if (sync_sink)
267 		snd_usb_handle_sync_urb(sync_sink, ep, urb);
268 
269 	call_retire_callback(ep, urb);
270 }
271 
272 static inline bool has_tx_length_quirk(struct snd_usb_audio *chip)
273 {
274 	return chip->quirk_flags & QUIRK_FLAG_TX_LENGTH;
275 }
276 
277 static void prepare_silent_urb(struct snd_usb_endpoint *ep,
278 			       struct snd_urb_ctx *ctx)
279 {
280 	struct urb *urb = ctx->urb;
281 	unsigned int offs = 0;
282 	unsigned int extra = 0;
283 	__le32 packet_length;
284 	int i;
285 
286 	/* For tx_length_quirk, put packet length at start of packet */
287 	if (has_tx_length_quirk(ep->chip))
288 		extra = sizeof(packet_length);
289 
290 	for (i = 0; i < ctx->packets; ++i) {
291 		unsigned int offset;
292 		unsigned int length;
293 		int counts;
294 
295 		counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, 0);
296 		length = counts * ep->stride; /* number of silent bytes */
297 		offset = offs * ep->stride + extra * i;
298 		urb->iso_frame_desc[i].offset = offset;
299 		urb->iso_frame_desc[i].length = length + extra;
300 		if (extra) {
301 			packet_length = cpu_to_le32(length);
302 			memcpy(urb->transfer_buffer + offset,
303 			       &packet_length, sizeof(packet_length));
304 		}
305 		memset(urb->transfer_buffer + offset + extra,
306 		       ep->silence_value, length);
307 		offs += counts;
308 	}
309 
310 	urb->number_of_packets = ctx->packets;
311 	urb->transfer_buffer_length = offs * ep->stride + ctx->packets * extra;
312 	ctx->queued = 0;
313 }
314 
315 /*
316  * Prepare a PLAYBACK urb for submission to the bus.
317  */
318 static int prepare_outbound_urb(struct snd_usb_endpoint *ep,
319 				struct snd_urb_ctx *ctx,
320 				bool in_stream_lock)
321 {
322 	struct urb *urb = ctx->urb;
323 	unsigned char *cp = urb->transfer_buffer;
324 	struct snd_usb_substream *data_subs;
325 
326 	urb->dev = ep->chip->dev; /* we need to set this at each time */
327 
328 	switch (ep->type) {
329 	case SND_USB_ENDPOINT_TYPE_DATA:
330 		data_subs = READ_ONCE(ep->data_subs);
331 		if (data_subs && ep->prepare_data_urb)
332 			return ep->prepare_data_urb(data_subs, urb, in_stream_lock);
333 		/* no data provider, so send silence */
334 		prepare_silent_urb(ep, ctx);
335 		break;
336 
337 	case SND_USB_ENDPOINT_TYPE_SYNC:
338 		if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
339 			/*
340 			 * fill the length and offset of each urb descriptor.
341 			 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
342 			 */
343 			urb->iso_frame_desc[0].length = 4;
344 			urb->iso_frame_desc[0].offset = 0;
345 			cp[0] = ep->freqn;
346 			cp[1] = ep->freqn >> 8;
347 			cp[2] = ep->freqn >> 16;
348 			cp[3] = ep->freqn >> 24;
349 		} else {
350 			/*
351 			 * fill the length and offset of each urb descriptor.
352 			 * the fixed 10.14 frequency is passed through the pipe.
353 			 */
354 			urb->iso_frame_desc[0].length = 3;
355 			urb->iso_frame_desc[0].offset = 0;
356 			cp[0] = ep->freqn >> 2;
357 			cp[1] = ep->freqn >> 10;
358 			cp[2] = ep->freqn >> 18;
359 		}
360 
361 		break;
362 	}
363 	return 0;
364 }
365 
366 /*
367  * Prepare a CAPTURE or SYNC urb for submission to the bus.
368  */
369 static int prepare_inbound_urb(struct snd_usb_endpoint *ep,
370 			       struct snd_urb_ctx *urb_ctx)
371 {
372 	int i, offs;
373 	struct urb *urb = urb_ctx->urb;
374 
375 	urb->dev = ep->chip->dev; /* we need to set this at each time */
376 
377 	switch (ep->type) {
378 	case SND_USB_ENDPOINT_TYPE_DATA:
379 		offs = 0;
380 		for (i = 0; i < urb_ctx->packets; i++) {
381 			urb->iso_frame_desc[i].offset = offs;
382 			urb->iso_frame_desc[i].length = ep->curpacksize;
383 			offs += ep->curpacksize;
384 		}
385 
386 		urb->transfer_buffer_length = offs;
387 		urb->number_of_packets = urb_ctx->packets;
388 		break;
389 
390 	case SND_USB_ENDPOINT_TYPE_SYNC:
391 		urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
392 		urb->iso_frame_desc[0].offset = 0;
393 		break;
394 	}
395 	return 0;
396 }
397 
398 /* notify an error as XRUN to the assigned PCM data substream */
399 static void notify_xrun(struct snd_usb_endpoint *ep)
400 {
401 	struct snd_usb_substream *data_subs;
402 
403 	data_subs = READ_ONCE(ep->data_subs);
404 	if (data_subs && data_subs->pcm_substream)
405 		snd_pcm_stop_xrun(data_subs->pcm_substream);
406 }
407 
408 static struct snd_usb_packet_info *
409 next_packet_fifo_enqueue(struct snd_usb_endpoint *ep)
410 {
411 	struct snd_usb_packet_info *p;
412 
413 	p = ep->next_packet + (ep->next_packet_head + ep->next_packet_queued) %
414 		ARRAY_SIZE(ep->next_packet);
415 	ep->next_packet_queued++;
416 	return p;
417 }
418 
419 static struct snd_usb_packet_info *
420 next_packet_fifo_dequeue(struct snd_usb_endpoint *ep)
421 {
422 	struct snd_usb_packet_info *p;
423 
424 	p = ep->next_packet + ep->next_packet_head;
425 	ep->next_packet_head++;
426 	ep->next_packet_head %= ARRAY_SIZE(ep->next_packet);
427 	ep->next_packet_queued--;
428 	return p;
429 }
430 
431 static void push_back_to_ready_list(struct snd_usb_endpoint *ep,
432 				    struct snd_urb_ctx *ctx)
433 {
434 	unsigned long flags;
435 
436 	spin_lock_irqsave(&ep->lock, flags);
437 	list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
438 	spin_unlock_irqrestore(&ep->lock, flags);
439 }
440 
441 /*
442  * Send output urbs that have been prepared previously. URBs are dequeued
443  * from ep->ready_playback_urbs and in case there aren't any available
444  * or there are no packets that have been prepared, this function does
445  * nothing.
446  *
447  * The reason why the functionality of sending and preparing URBs is separated
448  * is that host controllers don't guarantee the order in which they return
449  * inbound and outbound packets to their submitters.
450  *
451  * This function is used both for implicit feedback endpoints and in low-
452  * latency playback mode.
453  */
454 void snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep,
455 				       bool in_stream_lock)
456 {
457 	bool implicit_fb = snd_usb_endpoint_implicit_feedback_sink(ep);
458 
459 	while (ep_state_running(ep)) {
460 
461 		unsigned long flags;
462 		struct snd_usb_packet_info *packet;
463 		struct snd_urb_ctx *ctx = NULL;
464 		int err, i;
465 
466 		spin_lock_irqsave(&ep->lock, flags);
467 		if ((!implicit_fb || ep->next_packet_queued > 0) &&
468 		    !list_empty(&ep->ready_playback_urbs)) {
469 			/* take URB out of FIFO */
470 			ctx = list_first_entry(&ep->ready_playback_urbs,
471 					       struct snd_urb_ctx, ready_list);
472 			list_del_init(&ctx->ready_list);
473 			if (implicit_fb)
474 				packet = next_packet_fifo_dequeue(ep);
475 		}
476 		spin_unlock_irqrestore(&ep->lock, flags);
477 
478 		if (ctx == NULL)
479 			return;
480 
481 		/* copy over the length information */
482 		if (implicit_fb) {
483 			for (i = 0; i < packet->packets; i++)
484 				ctx->packet_size[i] = packet->packet_size[i];
485 		}
486 
487 		/* call the data handler to fill in playback data */
488 		err = prepare_outbound_urb(ep, ctx, in_stream_lock);
489 		/* can be stopped during prepare callback */
490 		if (unlikely(!ep_state_running(ep)))
491 			break;
492 		if (err < 0) {
493 			/* push back to ready list again for -EAGAIN */
494 			if (err == -EAGAIN)
495 				push_back_to_ready_list(ep, ctx);
496 			else
497 				notify_xrun(ep);
498 			return;
499 		}
500 
501 		err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
502 		if (err < 0) {
503 			usb_audio_err(ep->chip,
504 				      "Unable to submit urb #%d: %d at %s\n",
505 				      ctx->index, err, __func__);
506 			notify_xrun(ep);
507 			return;
508 		}
509 
510 		set_bit(ctx->index, &ep->active_mask);
511 		atomic_inc(&ep->submitted_urbs);
512 	}
513 }
514 
515 /*
516  * complete callback for urbs
517  */
518 static void snd_complete_urb(struct urb *urb)
519 {
520 	struct snd_urb_ctx *ctx = urb->context;
521 	struct snd_usb_endpoint *ep = ctx->ep;
522 	int err;
523 
524 	if (unlikely(urb->status == -ENOENT ||		/* unlinked */
525 		     urb->status == -ENODEV ||		/* device removed */
526 		     urb->status == -ECONNRESET ||	/* unlinked */
527 		     urb->status == -ESHUTDOWN))	/* device disabled */
528 		goto exit_clear;
529 	/* device disconnected */
530 	if (unlikely(atomic_read(&ep->chip->shutdown)))
531 		goto exit_clear;
532 
533 	if (unlikely(!ep_state_running(ep)))
534 		goto exit_clear;
535 
536 	if (usb_pipeout(ep->pipe)) {
537 		retire_outbound_urb(ep, ctx);
538 		/* can be stopped during retire callback */
539 		if (unlikely(!ep_state_running(ep)))
540 			goto exit_clear;
541 
542 		/* in low-latency and implicit-feedback modes, push back the
543 		 * URB to ready list at first, then process as much as possible
544 		 */
545 		if (ep->lowlatency_playback ||
546 		     snd_usb_endpoint_implicit_feedback_sink(ep)) {
547 			push_back_to_ready_list(ep, ctx);
548 			clear_bit(ctx->index, &ep->active_mask);
549 			snd_usb_queue_pending_output_urbs(ep, false);
550 			atomic_dec(&ep->submitted_urbs); /* decrement at last */
551 			return;
552 		}
553 
554 		/* in non-lowlatency mode, no error handling for prepare */
555 		prepare_outbound_urb(ep, ctx, false);
556 		/* can be stopped during prepare callback */
557 		if (unlikely(!ep_state_running(ep)))
558 			goto exit_clear;
559 	} else {
560 		retire_inbound_urb(ep, ctx);
561 		/* can be stopped during retire callback */
562 		if (unlikely(!ep_state_running(ep)))
563 			goto exit_clear;
564 
565 		prepare_inbound_urb(ep, ctx);
566 	}
567 
568 	err = usb_submit_urb(urb, GFP_ATOMIC);
569 	if (err == 0)
570 		return;
571 
572 	usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
573 	notify_xrun(ep);
574 
575 exit_clear:
576 	clear_bit(ctx->index, &ep->active_mask);
577 	atomic_dec(&ep->submitted_urbs);
578 }
579 
580 /*
581  * Find or create a refcount object for the given interface
582  *
583  * The objects are released altogether in snd_usb_endpoint_free_all()
584  */
585 static struct snd_usb_iface_ref *
586 iface_ref_find(struct snd_usb_audio *chip, int iface)
587 {
588 	struct snd_usb_iface_ref *ip;
589 
590 	list_for_each_entry(ip, &chip->iface_ref_list, list)
591 		if (ip->iface == iface)
592 			return ip;
593 
594 	ip = kzalloc(sizeof(*ip), GFP_KERNEL);
595 	if (!ip)
596 		return NULL;
597 	ip->iface = iface;
598 	list_add_tail(&ip->list, &chip->iface_ref_list);
599 	return ip;
600 }
601 
602 /* Similarly, a refcount object for clock */
603 static struct snd_usb_clock_ref *
604 clock_ref_find(struct snd_usb_audio *chip, int clock)
605 {
606 	struct snd_usb_clock_ref *ref;
607 
608 	list_for_each_entry(ref, &chip->clock_ref_list, list)
609 		if (ref->clock == clock)
610 			return ref;
611 
612 	ref = kzalloc(sizeof(*ref), GFP_KERNEL);
613 	if (!ref)
614 		return NULL;
615 	ref->clock = clock;
616 	atomic_set(&ref->locked, 0);
617 	list_add_tail(&ref->list, &chip->clock_ref_list);
618 	return ref;
619 }
620 
621 /*
622  * Get the existing endpoint object corresponding EP
623  * Returns NULL if not present.
624  */
625 struct snd_usb_endpoint *
626 snd_usb_get_endpoint(struct snd_usb_audio *chip, int ep_num)
627 {
628 	struct snd_usb_endpoint *ep;
629 
630 	list_for_each_entry(ep, &chip->ep_list, list) {
631 		if (ep->ep_num == ep_num)
632 			return ep;
633 	}
634 
635 	return NULL;
636 }
637 
638 #define ep_type_name(type) \
639 	(type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync")
640 
641 /**
642  * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
643  *
644  * @chip: The chip
645  * @ep_num: The number of the endpoint to use
646  * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
647  *
648  * If the requested endpoint has not been added to the given chip before,
649  * a new instance is created.
650  *
651  * Returns zero on success or a negative error code.
652  *
653  * New endpoints will be added to chip->ep_list and freed by
654  * calling snd_usb_endpoint_free_all().
655  *
656  * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
657  * bNumEndpoints > 1 beforehand.
658  */
659 int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type)
660 {
661 	struct snd_usb_endpoint *ep;
662 	bool is_playback;
663 
664 	ep = snd_usb_get_endpoint(chip, ep_num);
665 	if (ep)
666 		return 0;
667 
668 	usb_audio_dbg(chip, "Creating new %s endpoint #%x\n",
669 		      ep_type_name(type),
670 		      ep_num);
671 	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
672 	if (!ep)
673 		return -ENOMEM;
674 
675 	ep->chip = chip;
676 	spin_lock_init(&ep->lock);
677 	ep->type = type;
678 	ep->ep_num = ep_num;
679 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
680 	atomic_set(&ep->submitted_urbs, 0);
681 
682 	is_playback = ((ep_num & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT);
683 	ep_num &= USB_ENDPOINT_NUMBER_MASK;
684 	if (is_playback)
685 		ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
686 	else
687 		ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
688 
689 	list_add_tail(&ep->list, &chip->ep_list);
690 	return 0;
691 }
692 
693 /* Set up syncinterval and maxsyncsize for a sync EP */
694 static void endpoint_set_syncinterval(struct snd_usb_audio *chip,
695 				      struct snd_usb_endpoint *ep)
696 {
697 	struct usb_host_interface *alts;
698 	struct usb_endpoint_descriptor *desc;
699 
700 	alts = snd_usb_get_host_interface(chip, ep->iface, ep->altsetting);
701 	if (!alts)
702 		return;
703 
704 	desc = get_endpoint(alts, ep->ep_idx);
705 	if (desc->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
706 	    desc->bRefresh >= 1 && desc->bRefresh <= 9)
707 		ep->syncinterval = desc->bRefresh;
708 	else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
709 		ep->syncinterval = 1;
710 	else if (desc->bInterval >= 1 && desc->bInterval <= 16)
711 		ep->syncinterval = desc->bInterval - 1;
712 	else
713 		ep->syncinterval = 3;
714 
715 	ep->syncmaxsize = le16_to_cpu(desc->wMaxPacketSize);
716 }
717 
718 static bool endpoint_compatible(struct snd_usb_endpoint *ep,
719 				const struct audioformat *fp,
720 				const struct snd_pcm_hw_params *params)
721 {
722 	if (!ep->opened)
723 		return false;
724 	if (ep->cur_audiofmt != fp)
725 		return false;
726 	if (ep->cur_rate != params_rate(params) ||
727 	    ep->cur_format != params_format(params) ||
728 	    ep->cur_period_frames != params_period_size(params) ||
729 	    ep->cur_buffer_periods != params_periods(params))
730 		return false;
731 	return true;
732 }
733 
734 /*
735  * Check whether the given fp and hw params are compatible with the current
736  * setup of the target EP for implicit feedback sync
737  */
738 bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip,
739 				 struct snd_usb_endpoint *ep,
740 				 const struct audioformat *fp,
741 				 const struct snd_pcm_hw_params *params)
742 {
743 	bool ret;
744 
745 	mutex_lock(&chip->mutex);
746 	ret = endpoint_compatible(ep, fp, params);
747 	mutex_unlock(&chip->mutex);
748 	return ret;
749 }
750 
751 /*
752  * snd_usb_endpoint_open: Open the endpoint
753  *
754  * Called from hw_params to assign the endpoint to the substream.
755  * It's reference-counted, and only the first opener is allowed to set up
756  * arbitrary parameters.  The later opener must be compatible with the
757  * former opened parameters.
758  * The endpoint needs to be closed via snd_usb_endpoint_close() later.
759  *
760  * Note that this function doesn't configure the endpoint.  The substream
761  * needs to set it up later via snd_usb_endpoint_configure().
762  */
763 struct snd_usb_endpoint *
764 snd_usb_endpoint_open(struct snd_usb_audio *chip,
765 		      const struct audioformat *fp,
766 		      const struct snd_pcm_hw_params *params,
767 		      bool is_sync_ep)
768 {
769 	struct snd_usb_endpoint *ep;
770 	int ep_num = is_sync_ep ? fp->sync_ep : fp->endpoint;
771 
772 	mutex_lock(&chip->mutex);
773 	ep = snd_usb_get_endpoint(chip, ep_num);
774 	if (!ep) {
775 		usb_audio_err(chip, "Cannot find EP 0x%x to open\n", ep_num);
776 		goto unlock;
777 	}
778 
779 	if (!ep->opened) {
780 		if (is_sync_ep) {
781 			ep->iface = fp->sync_iface;
782 			ep->altsetting = fp->sync_altsetting;
783 			ep->ep_idx = fp->sync_ep_idx;
784 		} else {
785 			ep->iface = fp->iface;
786 			ep->altsetting = fp->altsetting;
787 			ep->ep_idx = fp->ep_idx;
788 		}
789 		usb_audio_dbg(chip, "Open EP 0x%x, iface=%d:%d, idx=%d\n",
790 			      ep_num, ep->iface, ep->altsetting, ep->ep_idx);
791 
792 		ep->iface_ref = iface_ref_find(chip, ep->iface);
793 		if (!ep->iface_ref) {
794 			ep = NULL;
795 			goto unlock;
796 		}
797 
798 		if (fp->protocol != UAC_VERSION_1) {
799 			ep->clock_ref = clock_ref_find(chip, fp->clock);
800 			if (!ep->clock_ref) {
801 				ep = NULL;
802 				goto unlock;
803 			}
804 		}
805 
806 		ep->cur_audiofmt = fp;
807 		ep->cur_channels = fp->channels;
808 		ep->cur_rate = params_rate(params);
809 		ep->cur_format = params_format(params);
810 		ep->cur_frame_bytes = snd_pcm_format_physical_width(ep->cur_format) *
811 			ep->cur_channels / 8;
812 		ep->cur_period_frames = params_period_size(params);
813 		ep->cur_period_bytes = ep->cur_period_frames * ep->cur_frame_bytes;
814 		ep->cur_buffer_periods = params_periods(params);
815 
816 		if (ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
817 			endpoint_set_syncinterval(chip, ep);
818 
819 		ep->implicit_fb_sync = fp->implicit_fb;
820 		ep->need_setup = true;
821 
822 		usb_audio_dbg(chip, "  channels=%d, rate=%d, format=%s, period_bytes=%d, periods=%d, implicit_fb=%d\n",
823 			      ep->cur_channels, ep->cur_rate,
824 			      snd_pcm_format_name(ep->cur_format),
825 			      ep->cur_period_bytes, ep->cur_buffer_periods,
826 			      ep->implicit_fb_sync);
827 
828 	} else {
829 		if (WARN_ON(!ep->iface_ref)) {
830 			ep = NULL;
831 			goto unlock;
832 		}
833 
834 		if (!endpoint_compatible(ep, fp, params)) {
835 			usb_audio_err(chip, "Incompatible EP setup for 0x%x\n",
836 				      ep_num);
837 			ep = NULL;
838 			goto unlock;
839 		}
840 
841 		usb_audio_dbg(chip, "Reopened EP 0x%x (count %d)\n",
842 			      ep_num, ep->opened);
843 	}
844 
845 	if (!ep->iface_ref->opened++)
846 		ep->iface_ref->need_setup = true;
847 
848 	ep->opened++;
849 
850  unlock:
851 	mutex_unlock(&chip->mutex);
852 	return ep;
853 }
854 
855 /*
856  * snd_usb_endpoint_set_sync: Link data and sync endpoints
857  *
858  * Pass NULL to sync_ep to unlink again
859  */
860 void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
861 			       struct snd_usb_endpoint *data_ep,
862 			       struct snd_usb_endpoint *sync_ep)
863 {
864 	data_ep->sync_source = sync_ep;
865 }
866 
867 /*
868  * Set data endpoint callbacks and the assigned data stream
869  *
870  * Called at PCM trigger and cleanups.
871  * Pass NULL to deactivate each callback.
872  */
873 void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
874 				   int (*prepare)(struct snd_usb_substream *subs,
875 						  struct urb *urb,
876 						  bool in_stream_lock),
877 				   void (*retire)(struct snd_usb_substream *subs,
878 						  struct urb *urb),
879 				   struct snd_usb_substream *data_subs)
880 {
881 	ep->prepare_data_urb = prepare;
882 	ep->retire_data_urb = retire;
883 	if (data_subs)
884 		ep->lowlatency_playback = data_subs->lowlatency_playback;
885 	else
886 		ep->lowlatency_playback = false;
887 	WRITE_ONCE(ep->data_subs, data_subs);
888 }
889 
890 static int endpoint_set_interface(struct snd_usb_audio *chip,
891 				  struct snd_usb_endpoint *ep,
892 				  bool set)
893 {
894 	int altset = set ? ep->altsetting : 0;
895 	int err;
896 
897 	usb_audio_dbg(chip, "Setting usb interface %d:%d for EP 0x%x\n",
898 		      ep->iface, altset, ep->ep_num);
899 	err = usb_set_interface(chip->dev, ep->iface, altset);
900 	if (err < 0) {
901 		usb_audio_err(chip, "%d:%d: usb_set_interface failed (%d)\n",
902 			      ep->iface, altset, err);
903 		return err;
904 	}
905 
906 	if (chip->quirk_flags & QUIRK_FLAG_IFACE_DELAY)
907 		msleep(50);
908 	return 0;
909 }
910 
911 /*
912  * snd_usb_endpoint_close: Close the endpoint
913  *
914  * Unreference the already opened endpoint via snd_usb_endpoint_open().
915  */
916 void snd_usb_endpoint_close(struct snd_usb_audio *chip,
917 			    struct snd_usb_endpoint *ep)
918 {
919 	mutex_lock(&chip->mutex);
920 	usb_audio_dbg(chip, "Closing EP 0x%x (count %d)\n",
921 		      ep->ep_num, ep->opened);
922 
923 	if (!--ep->iface_ref->opened)
924 		endpoint_set_interface(chip, ep, false);
925 
926 	if (!--ep->opened) {
927 		ep->iface = 0;
928 		ep->altsetting = 0;
929 		ep->cur_audiofmt = NULL;
930 		ep->cur_rate = 0;
931 		ep->iface_ref = NULL;
932 		ep->clock_ref = NULL;
933 		usb_audio_dbg(chip, "EP 0x%x closed\n", ep->ep_num);
934 	}
935 	mutex_unlock(&chip->mutex);
936 }
937 
938 /* Prepare for suspening EP, called from the main suspend handler */
939 void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep)
940 {
941 	ep->need_setup = true;
942 	if (ep->iface_ref)
943 		ep->iface_ref->need_setup = true;
944 	if (ep->clock_ref)
945 		ep->clock_ref->rate = 0;
946 }
947 
948 /*
949  *  wait until all urbs are processed.
950  */
951 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
952 {
953 	unsigned long end_time = jiffies + msecs_to_jiffies(1000);
954 	int alive;
955 
956 	if (atomic_read(&ep->state) != EP_STATE_STOPPING)
957 		return 0;
958 
959 	do {
960 		alive = atomic_read(&ep->submitted_urbs);
961 		if (!alive)
962 			break;
963 
964 		schedule_timeout_uninterruptible(1);
965 	} while (time_before(jiffies, end_time));
966 
967 	if (alive)
968 		usb_audio_err(ep->chip,
969 			"timeout: still %d active urbs on EP #%x\n",
970 			alive, ep->ep_num);
971 
972 	if (ep_state_update(ep, EP_STATE_STOPPING, EP_STATE_STOPPED)) {
973 		ep->sync_sink = NULL;
974 		snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
975 	}
976 
977 	return 0;
978 }
979 
980 /* sync the pending stop operation;
981  * this function itself doesn't trigger the stop operation
982  */
983 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
984 {
985 	if (ep)
986 		wait_clear_urbs(ep);
987 }
988 
989 /*
990  * Stop active urbs
991  *
992  * This function moves the EP to STOPPING state if it's being RUNNING.
993  */
994 static int stop_urbs(struct snd_usb_endpoint *ep, bool force, bool keep_pending)
995 {
996 	unsigned int i;
997 	unsigned long flags;
998 
999 	if (!force && atomic_read(&ep->running))
1000 		return -EBUSY;
1001 
1002 	if (!ep_state_update(ep, EP_STATE_RUNNING, EP_STATE_STOPPING))
1003 		return 0;
1004 
1005 	spin_lock_irqsave(&ep->lock, flags);
1006 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
1007 	ep->next_packet_head = 0;
1008 	ep->next_packet_queued = 0;
1009 	spin_unlock_irqrestore(&ep->lock, flags);
1010 
1011 	if (keep_pending)
1012 		return 0;
1013 
1014 	for (i = 0; i < ep->nurbs; i++) {
1015 		if (test_bit(i, &ep->active_mask)) {
1016 			if (!test_and_set_bit(i, &ep->unlink_mask)) {
1017 				struct urb *u = ep->urb[i].urb;
1018 				usb_unlink_urb(u);
1019 			}
1020 		}
1021 	}
1022 
1023 	return 0;
1024 }
1025 
1026 /*
1027  * release an endpoint's urbs
1028  */
1029 static int release_urbs(struct snd_usb_endpoint *ep, bool force)
1030 {
1031 	int i, err;
1032 
1033 	/* route incoming urbs to nirvana */
1034 	snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
1035 
1036 	/* stop and unlink urbs */
1037 	err = stop_urbs(ep, force, false);
1038 	if (err)
1039 		return err;
1040 
1041 	wait_clear_urbs(ep);
1042 
1043 	for (i = 0; i < ep->nurbs; i++)
1044 		release_urb_ctx(&ep->urb[i]);
1045 
1046 	usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
1047 			  ep->syncbuf, ep->sync_dma);
1048 
1049 	ep->syncbuf = NULL;
1050 	ep->nurbs = 0;
1051 	return 0;
1052 }
1053 
1054 /*
1055  * configure a data endpoint
1056  */
1057 static int data_ep_set_params(struct snd_usb_endpoint *ep)
1058 {
1059 	struct snd_usb_audio *chip = ep->chip;
1060 	unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
1061 	unsigned int max_packs_per_period, urbs_per_period, urb_packs;
1062 	unsigned int max_urbs, i;
1063 	const struct audioformat *fmt = ep->cur_audiofmt;
1064 	int frame_bits = ep->cur_frame_bytes * 8;
1065 	int tx_length_quirk = (has_tx_length_quirk(chip) &&
1066 			       usb_pipeout(ep->pipe));
1067 
1068 	usb_audio_dbg(chip, "Setting params for data EP 0x%x, pipe 0x%x\n",
1069 		      ep->ep_num, ep->pipe);
1070 
1071 	if (ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
1072 		/*
1073 		 * When operating in DSD DOP mode, the size of a sample frame
1074 		 * in hardware differs from the actual physical format width
1075 		 * because we need to make room for the DOP markers.
1076 		 */
1077 		frame_bits += ep->cur_channels << 3;
1078 	}
1079 
1080 	ep->datainterval = fmt->datainterval;
1081 	ep->stride = frame_bits >> 3;
1082 
1083 	switch (ep->cur_format) {
1084 	case SNDRV_PCM_FORMAT_U8:
1085 		ep->silence_value = 0x80;
1086 		break;
1087 	case SNDRV_PCM_FORMAT_DSD_U8:
1088 	case SNDRV_PCM_FORMAT_DSD_U16_LE:
1089 	case SNDRV_PCM_FORMAT_DSD_U32_LE:
1090 	case SNDRV_PCM_FORMAT_DSD_U16_BE:
1091 	case SNDRV_PCM_FORMAT_DSD_U32_BE:
1092 		ep->silence_value = 0x69;
1093 		break;
1094 	default:
1095 		ep->silence_value = 0;
1096 	}
1097 
1098 	/* assume max. frequency is 50% higher than nominal */
1099 	ep->freqmax = ep->freqn + (ep->freqn >> 1);
1100 	/* Round up freqmax to nearest integer in order to calculate maximum
1101 	 * packet size, which must represent a whole number of frames.
1102 	 * This is accomplished by adding 0x0.ffff before converting the
1103 	 * Q16.16 format into integer.
1104 	 * In order to accurately calculate the maximum packet size when
1105 	 * the data interval is more than 1 (i.e. ep->datainterval > 0),
1106 	 * multiply by the data interval prior to rounding. For instance,
1107 	 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
1108 	 * frames with a data interval of 1, but 11 (10.25) frames with a
1109 	 * data interval of 2.
1110 	 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
1111 	 * maximum datainterval value of 3, at USB full speed, higher for
1112 	 * USB high speed, noting that ep->freqmax is in units of
1113 	 * frames per packet in Q16.16 format.)
1114 	 */
1115 	maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
1116 			 (frame_bits >> 3);
1117 	if (tx_length_quirk)
1118 		maxsize += sizeof(__le32); /* Space for length descriptor */
1119 	/* but wMaxPacketSize might reduce this */
1120 	if (ep->maxpacksize && ep->maxpacksize < maxsize) {
1121 		/* whatever fits into a max. size packet */
1122 		unsigned int data_maxsize = maxsize = ep->maxpacksize;
1123 
1124 		if (tx_length_quirk)
1125 			/* Need to remove the length descriptor to calc freq */
1126 			data_maxsize -= sizeof(__le32);
1127 		ep->freqmax = (data_maxsize / (frame_bits >> 3))
1128 				<< (16 - ep->datainterval);
1129 	}
1130 
1131 	if (ep->fill_max)
1132 		ep->curpacksize = ep->maxpacksize;
1133 	else
1134 		ep->curpacksize = maxsize;
1135 
1136 	if (snd_usb_get_speed(chip->dev) != USB_SPEED_FULL) {
1137 		packs_per_ms = 8 >> ep->datainterval;
1138 		max_packs_per_urb = MAX_PACKS_HS;
1139 	} else {
1140 		packs_per_ms = 1;
1141 		max_packs_per_urb = MAX_PACKS;
1142 	}
1143 	if (ep->sync_source && !ep->implicit_fb_sync)
1144 		max_packs_per_urb = min(max_packs_per_urb,
1145 					1U << ep->sync_source->syncinterval);
1146 	max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
1147 
1148 	/*
1149 	 * Capture endpoints need to use small URBs because there's no way
1150 	 * to tell in advance where the next period will end, and we don't
1151 	 * want the next URB to complete much after the period ends.
1152 	 *
1153 	 * Playback endpoints with implicit sync much use the same parameters
1154 	 * as their corresponding capture endpoint.
1155 	 */
1156 	if (usb_pipein(ep->pipe) || ep->implicit_fb_sync) {
1157 
1158 		urb_packs = packs_per_ms;
1159 		/*
1160 		 * Wireless devices can poll at a max rate of once per 4ms.
1161 		 * For dataintervals less than 5, increase the packet count to
1162 		 * allow the host controller to use bursting to fill in the
1163 		 * gaps.
1164 		 */
1165 		if (snd_usb_get_speed(chip->dev) == USB_SPEED_WIRELESS) {
1166 			int interval = ep->datainterval;
1167 			while (interval < 5) {
1168 				urb_packs <<= 1;
1169 				++interval;
1170 			}
1171 		}
1172 		/* make capture URBs <= 1 ms and smaller than a period */
1173 		urb_packs = min(max_packs_per_urb, urb_packs);
1174 		while (urb_packs > 1 && urb_packs * maxsize >= ep->cur_period_bytes)
1175 			urb_packs >>= 1;
1176 		ep->nurbs = MAX_URBS;
1177 
1178 	/*
1179 	 * Playback endpoints without implicit sync are adjusted so that
1180 	 * a period fits as evenly as possible in the smallest number of
1181 	 * URBs.  The total number of URBs is adjusted to the size of the
1182 	 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
1183 	 */
1184 	} else {
1185 		/* determine how small a packet can be */
1186 		minsize = (ep->freqn >> (16 - ep->datainterval)) *
1187 				(frame_bits >> 3);
1188 		/* with sync from device, assume it can be 12% lower */
1189 		if (ep->sync_source)
1190 			minsize -= minsize >> 3;
1191 		minsize = max(minsize, 1u);
1192 
1193 		/* how many packets will contain an entire ALSA period? */
1194 		max_packs_per_period = DIV_ROUND_UP(ep->cur_period_bytes, minsize);
1195 
1196 		/* how many URBs will contain a period? */
1197 		urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
1198 				max_packs_per_urb);
1199 		/* how many packets are needed in each URB? */
1200 		urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
1201 
1202 		/* limit the number of frames in a single URB */
1203 		ep->max_urb_frames = DIV_ROUND_UP(ep->cur_period_frames,
1204 						  urbs_per_period);
1205 
1206 		/* try to use enough URBs to contain an entire ALSA buffer */
1207 		max_urbs = min((unsigned) MAX_URBS,
1208 				MAX_QUEUE * packs_per_ms / urb_packs);
1209 		ep->nurbs = min(max_urbs, urbs_per_period * ep->cur_buffer_periods);
1210 	}
1211 
1212 	/* allocate and initialize data urbs */
1213 	for (i = 0; i < ep->nurbs; i++) {
1214 		struct snd_urb_ctx *u = &ep->urb[i];
1215 		u->index = i;
1216 		u->ep = ep;
1217 		u->packets = urb_packs;
1218 		u->buffer_size = maxsize * u->packets;
1219 
1220 		if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
1221 			u->packets++; /* for transfer delimiter */
1222 		u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
1223 		if (!u->urb)
1224 			goto out_of_memory;
1225 
1226 		u->urb->transfer_buffer =
1227 			usb_alloc_coherent(chip->dev, u->buffer_size,
1228 					   GFP_KERNEL, &u->urb->transfer_dma);
1229 		if (!u->urb->transfer_buffer)
1230 			goto out_of_memory;
1231 		u->urb->pipe = ep->pipe;
1232 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1233 		u->urb->interval = 1 << ep->datainterval;
1234 		u->urb->context = u;
1235 		u->urb->complete = snd_complete_urb;
1236 		INIT_LIST_HEAD(&u->ready_list);
1237 	}
1238 
1239 	return 0;
1240 
1241 out_of_memory:
1242 	release_urbs(ep, false);
1243 	return -ENOMEM;
1244 }
1245 
1246 /*
1247  * configure a sync endpoint
1248  */
1249 static int sync_ep_set_params(struct snd_usb_endpoint *ep)
1250 {
1251 	struct snd_usb_audio *chip = ep->chip;
1252 	int i;
1253 
1254 	usb_audio_dbg(chip, "Setting params for sync EP 0x%x, pipe 0x%x\n",
1255 		      ep->ep_num, ep->pipe);
1256 
1257 	ep->syncbuf = usb_alloc_coherent(chip->dev, SYNC_URBS * 4,
1258 					 GFP_KERNEL, &ep->sync_dma);
1259 	if (!ep->syncbuf)
1260 		return -ENOMEM;
1261 
1262 	for (i = 0; i < SYNC_URBS; i++) {
1263 		struct snd_urb_ctx *u = &ep->urb[i];
1264 		u->index = i;
1265 		u->ep = ep;
1266 		u->packets = 1;
1267 		u->urb = usb_alloc_urb(1, GFP_KERNEL);
1268 		if (!u->urb)
1269 			goto out_of_memory;
1270 		u->urb->transfer_buffer = ep->syncbuf + i * 4;
1271 		u->urb->transfer_dma = ep->sync_dma + i * 4;
1272 		u->urb->transfer_buffer_length = 4;
1273 		u->urb->pipe = ep->pipe;
1274 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1275 		u->urb->number_of_packets = 1;
1276 		u->urb->interval = 1 << ep->syncinterval;
1277 		u->urb->context = u;
1278 		u->urb->complete = snd_complete_urb;
1279 	}
1280 
1281 	ep->nurbs = SYNC_URBS;
1282 
1283 	return 0;
1284 
1285 out_of_memory:
1286 	release_urbs(ep, false);
1287 	return -ENOMEM;
1288 }
1289 
1290 /*
1291  * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
1292  *
1293  * Determine the number of URBs to be used on this endpoint.
1294  * An endpoint must be configured before it can be started.
1295  * An endpoint that is already running can not be reconfigured.
1296  */
1297 static int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
1298 				       struct snd_usb_endpoint *ep)
1299 {
1300 	const struct audioformat *fmt = ep->cur_audiofmt;
1301 	int err;
1302 
1303 	/* release old buffers, if any */
1304 	err = release_urbs(ep, false);
1305 	if (err < 0)
1306 		return err;
1307 
1308 	ep->datainterval = fmt->datainterval;
1309 	ep->maxpacksize = fmt->maxpacksize;
1310 	ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
1311 
1312 	if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) {
1313 		ep->freqn = get_usb_full_speed_rate(ep->cur_rate);
1314 		ep->pps = 1000 >> ep->datainterval;
1315 	} else {
1316 		ep->freqn = get_usb_high_speed_rate(ep->cur_rate);
1317 		ep->pps = 8000 >> ep->datainterval;
1318 	}
1319 
1320 	ep->sample_rem = ep->cur_rate % ep->pps;
1321 	ep->packsize[0] = ep->cur_rate / ep->pps;
1322 	ep->packsize[1] = (ep->cur_rate + (ep->pps - 1)) / ep->pps;
1323 
1324 	/* calculate the frequency in 16.16 format */
1325 	ep->freqm = ep->freqn;
1326 	ep->freqshift = INT_MIN;
1327 
1328 	ep->phase = 0;
1329 
1330 	switch (ep->type) {
1331 	case  SND_USB_ENDPOINT_TYPE_DATA:
1332 		err = data_ep_set_params(ep);
1333 		break;
1334 	case  SND_USB_ENDPOINT_TYPE_SYNC:
1335 		err = sync_ep_set_params(ep);
1336 		break;
1337 	default:
1338 		err = -EINVAL;
1339 	}
1340 
1341 	usb_audio_dbg(chip, "Set up %d URBS, ret=%d\n", ep->nurbs, err);
1342 
1343 	if (err < 0)
1344 		return err;
1345 
1346 	/* some unit conversions in runtime */
1347 	ep->maxframesize = ep->maxpacksize / ep->cur_frame_bytes;
1348 	ep->curframesize = ep->curpacksize / ep->cur_frame_bytes;
1349 
1350 	return 0;
1351 }
1352 
1353 static int init_sample_rate(struct snd_usb_audio *chip,
1354 			    struct snd_usb_endpoint *ep)
1355 {
1356 	struct snd_usb_clock_ref *clock = ep->clock_ref;
1357 	int err;
1358 
1359 	if (clock) {
1360 		if (atomic_read(&clock->locked))
1361 			return 0;
1362 		if (clock->rate == ep->cur_rate)
1363 			return 0;
1364 		if (clock->rate && clock->rate != ep->cur_rate) {
1365 			usb_audio_dbg(chip, "Mismatched sample rate %d vs %d for EP 0x%x\n",
1366 				      clock->rate, ep->cur_rate, ep->ep_num);
1367 			return -EINVAL;
1368 		}
1369 	}
1370 
1371 	err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, ep->cur_rate);
1372 	if (err < 0)
1373 		return err;
1374 
1375 	if (clock)
1376 		clock->rate = ep->cur_rate;
1377 	return 0;
1378 }
1379 
1380 /*
1381  * snd_usb_endpoint_configure: Configure the endpoint
1382  *
1383  * This function sets up the EP to be fully usable state.
1384  * It's called either from hw_params or prepare callback.
1385  * The function checks need_setup flag, and performs nothing unless needed,
1386  * so it's safe to call this multiple times.
1387  *
1388  * This returns zero if unchanged, 1 if the configuration has changed,
1389  * or a negative error code.
1390  */
1391 int snd_usb_endpoint_configure(struct snd_usb_audio *chip,
1392 			       struct snd_usb_endpoint *ep)
1393 {
1394 	bool iface_first;
1395 	int err = 0;
1396 
1397 	mutex_lock(&chip->mutex);
1398 	if (WARN_ON(!ep->iface_ref))
1399 		goto unlock;
1400 	if (!ep->need_setup)
1401 		goto unlock;
1402 
1403 	/* If the interface has been already set up, just set EP parameters */
1404 	if (!ep->iface_ref->need_setup) {
1405 		/* sample rate setup of UAC1 is per endpoint, and we need
1406 		 * to update at each EP configuration
1407 		 */
1408 		if (ep->cur_audiofmt->protocol == UAC_VERSION_1) {
1409 			err = init_sample_rate(chip, ep);
1410 			if (err < 0)
1411 				goto unlock;
1412 		}
1413 		err = snd_usb_endpoint_set_params(chip, ep);
1414 		if (err < 0)
1415 			goto unlock;
1416 		goto done;
1417 	}
1418 
1419 	/* Need to deselect altsetting at first */
1420 	endpoint_set_interface(chip, ep, false);
1421 
1422 	/* Some UAC1 devices (e.g. Yamaha THR10) need the host interface
1423 	 * to be set up before parameter setups
1424 	 */
1425 	iface_first = ep->cur_audiofmt->protocol == UAC_VERSION_1;
1426 	/* Workaround for devices that require the interface setup at first like UAC1 */
1427 	if (chip->quirk_flags & QUIRK_FLAG_SET_IFACE_FIRST)
1428 		iface_first = true;
1429 	if (iface_first) {
1430 		err = endpoint_set_interface(chip, ep, true);
1431 		if (err < 0)
1432 			goto unlock;
1433 	}
1434 
1435 	err = snd_usb_init_pitch(chip, ep->cur_audiofmt);
1436 	if (err < 0)
1437 		goto unlock;
1438 
1439 	err = init_sample_rate(chip, ep);
1440 	if (err < 0)
1441 		goto unlock;
1442 
1443 	err = snd_usb_endpoint_set_params(chip, ep);
1444 	if (err < 0)
1445 		goto unlock;
1446 
1447 	err = snd_usb_select_mode_quirk(chip, ep->cur_audiofmt);
1448 	if (err < 0)
1449 		goto unlock;
1450 
1451 	/* for UAC2/3, enable the interface altset here at last */
1452 	if (!iface_first) {
1453 		err = endpoint_set_interface(chip, ep, true);
1454 		if (err < 0)
1455 			goto unlock;
1456 	}
1457 
1458 	ep->iface_ref->need_setup = false;
1459 
1460  done:
1461 	ep->need_setup = false;
1462 	err = 1;
1463 
1464 unlock:
1465 	mutex_unlock(&chip->mutex);
1466 	return err;
1467 }
1468 
1469 /* get the current rate set to the given clock by any endpoint */
1470 int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock)
1471 {
1472 	struct snd_usb_clock_ref *ref;
1473 	int rate = 0;
1474 
1475 	if (!clock)
1476 		return 0;
1477 	mutex_lock(&chip->mutex);
1478 	list_for_each_entry(ref, &chip->clock_ref_list, list) {
1479 		if (ref->clock == clock) {
1480 			rate = ref->rate;
1481 			break;
1482 		}
1483 	}
1484 	mutex_unlock(&chip->mutex);
1485 	return rate;
1486 }
1487 
1488 /**
1489  * snd_usb_endpoint_start: start an snd_usb_endpoint
1490  *
1491  * @ep: the endpoint to start
1492  *
1493  * A call to this function will increment the running count of the endpoint.
1494  * In case it is not already running, the URBs for this endpoint will be
1495  * submitted. Otherwise, this function does nothing.
1496  *
1497  * Must be balanced to calls of snd_usb_endpoint_stop().
1498  *
1499  * Returns an error if the URB submission failed, 0 in all other cases.
1500  */
1501 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
1502 {
1503 	bool is_playback = usb_pipeout(ep->pipe);
1504 	int err;
1505 	unsigned int i;
1506 
1507 	if (atomic_read(&ep->chip->shutdown))
1508 		return -EBADFD;
1509 
1510 	if (ep->sync_source)
1511 		WRITE_ONCE(ep->sync_source->sync_sink, ep);
1512 
1513 	usb_audio_dbg(ep->chip, "Starting %s EP 0x%x (running %d)\n",
1514 		      ep_type_name(ep->type), ep->ep_num,
1515 		      atomic_read(&ep->running));
1516 
1517 	/* already running? */
1518 	if (atomic_inc_return(&ep->running) != 1)
1519 		return 0;
1520 
1521 	if (ep->clock_ref)
1522 		atomic_inc(&ep->clock_ref->locked);
1523 
1524 	ep->active_mask = 0;
1525 	ep->unlink_mask = 0;
1526 	ep->phase = 0;
1527 	ep->sample_accum = 0;
1528 
1529 	snd_usb_endpoint_start_quirk(ep);
1530 
1531 	/*
1532 	 * If this endpoint has a data endpoint as implicit feedback source,
1533 	 * don't start the urbs here. Instead, mark them all as available,
1534 	 * wait for the record urbs to return and queue the playback urbs
1535 	 * from that context.
1536 	 */
1537 
1538 	if (!ep_state_update(ep, EP_STATE_STOPPED, EP_STATE_RUNNING))
1539 		goto __error;
1540 
1541 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1542 	    !(ep->chip->quirk_flags & QUIRK_FLAG_PLAYBACK_FIRST)) {
1543 		usb_audio_dbg(ep->chip, "No URB submission due to implicit fb sync\n");
1544 		i = 0;
1545 		goto fill_rest;
1546 	}
1547 
1548 	for (i = 0; i < ep->nurbs; i++) {
1549 		struct urb *urb = ep->urb[i].urb;
1550 
1551 		if (snd_BUG_ON(!urb))
1552 			goto __error;
1553 
1554 		if (is_playback)
1555 			err = prepare_outbound_urb(ep, urb->context, true);
1556 		else
1557 			err = prepare_inbound_urb(ep, urb->context);
1558 		if (err < 0) {
1559 			/* stop filling at applptr */
1560 			if (err == -EAGAIN)
1561 				break;
1562 			usb_audio_dbg(ep->chip,
1563 				      "EP 0x%x: failed to prepare urb: %d\n",
1564 				      ep->ep_num, err);
1565 			goto __error;
1566 		}
1567 
1568 		err = usb_submit_urb(urb, GFP_ATOMIC);
1569 		if (err < 0) {
1570 			usb_audio_err(ep->chip,
1571 				"cannot submit urb %d, error %d: %s\n",
1572 				i, err, usb_error_string(err));
1573 			goto __error;
1574 		}
1575 		set_bit(i, &ep->active_mask);
1576 		atomic_inc(&ep->submitted_urbs);
1577 	}
1578 
1579 	if (!i) {
1580 		usb_audio_dbg(ep->chip, "XRUN at starting EP 0x%x\n",
1581 			      ep->ep_num);
1582 		goto __error;
1583 	}
1584 
1585 	usb_audio_dbg(ep->chip, "%d URBs submitted for EP 0x%x\n",
1586 		      i, ep->ep_num);
1587 
1588  fill_rest:
1589 	/* put the remaining URBs to ready list */
1590 	if (is_playback) {
1591 		for (; i < ep->nurbs; i++)
1592 			push_back_to_ready_list(ep, ep->urb + i);
1593 	}
1594 
1595 	return 0;
1596 
1597 __error:
1598 	snd_usb_endpoint_stop(ep, false);
1599 	return -EPIPE;
1600 }
1601 
1602 /**
1603  * snd_usb_endpoint_stop: stop an snd_usb_endpoint
1604  *
1605  * @ep: the endpoint to stop (may be NULL)
1606  * @keep_pending: keep in-flight URBs
1607  *
1608  * A call to this function will decrement the running count of the endpoint.
1609  * In case the last user has requested the endpoint stop, the URBs will
1610  * actually be deactivated.
1611  *
1612  * Must be balanced to calls of snd_usb_endpoint_start().
1613  *
1614  * The caller needs to synchronize the pending stop operation via
1615  * snd_usb_endpoint_sync_pending_stop().
1616  */
1617 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending)
1618 {
1619 	if (!ep)
1620 		return;
1621 
1622 	usb_audio_dbg(ep->chip, "Stopping %s EP 0x%x (running %d)\n",
1623 		      ep_type_name(ep->type), ep->ep_num,
1624 		      atomic_read(&ep->running));
1625 
1626 	if (snd_BUG_ON(!atomic_read(&ep->running)))
1627 		return;
1628 
1629 	if (!atomic_dec_return(&ep->running)) {
1630 		if (ep->sync_source)
1631 			WRITE_ONCE(ep->sync_source->sync_sink, NULL);
1632 		stop_urbs(ep, false, keep_pending);
1633 		if (ep->clock_ref)
1634 			if (!atomic_dec_return(&ep->clock_ref->locked))
1635 				ep->clock_ref->rate = 0;
1636 	}
1637 }
1638 
1639 /**
1640  * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1641  *
1642  * @ep: the endpoint to release
1643  *
1644  * This function does not care for the endpoint's running count but will tear
1645  * down all the streaming URBs immediately.
1646  */
1647 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1648 {
1649 	release_urbs(ep, true);
1650 }
1651 
1652 /**
1653  * snd_usb_endpoint_free_all: Free the resources of an snd_usb_endpoint
1654  * @chip: The chip
1655  *
1656  * This free all endpoints and those resources
1657  */
1658 void snd_usb_endpoint_free_all(struct snd_usb_audio *chip)
1659 {
1660 	struct snd_usb_endpoint *ep, *en;
1661 	struct snd_usb_iface_ref *ip, *in;
1662 	struct snd_usb_clock_ref *cp, *cn;
1663 
1664 	list_for_each_entry_safe(ep, en, &chip->ep_list, list)
1665 		kfree(ep);
1666 
1667 	list_for_each_entry_safe(ip, in, &chip->iface_ref_list, list)
1668 		kfree(ip);
1669 
1670 	list_for_each_entry_safe(cp, cn, &chip->clock_ref_list, list)
1671 		kfree(cp);
1672 }
1673 
1674 /*
1675  * snd_usb_handle_sync_urb: parse an USB sync packet
1676  *
1677  * @ep: the endpoint to handle the packet
1678  * @sender: the sending endpoint
1679  * @urb: the received packet
1680  *
1681  * This function is called from the context of an endpoint that received
1682  * the packet and is used to let another endpoint object handle the payload.
1683  */
1684 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1685 				    struct snd_usb_endpoint *sender,
1686 				    const struct urb *urb)
1687 {
1688 	int shift;
1689 	unsigned int f;
1690 	unsigned long flags;
1691 
1692 	snd_BUG_ON(ep == sender);
1693 
1694 	/*
1695 	 * In case the endpoint is operating in implicit feedback mode, prepare
1696 	 * a new outbound URB that has the same layout as the received packet
1697 	 * and add it to the list of pending urbs. queue_pending_output_urbs()
1698 	 * will take care of them later.
1699 	 */
1700 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1701 	    atomic_read(&ep->running)) {
1702 
1703 		/* implicit feedback case */
1704 		int i, bytes = 0;
1705 		struct snd_urb_ctx *in_ctx;
1706 		struct snd_usb_packet_info *out_packet;
1707 
1708 		in_ctx = urb->context;
1709 
1710 		/* Count overall packet size */
1711 		for (i = 0; i < in_ctx->packets; i++)
1712 			if (urb->iso_frame_desc[i].status == 0)
1713 				bytes += urb->iso_frame_desc[i].actual_length;
1714 
1715 		/*
1716 		 * skip empty packets. At least M-Audio's Fast Track Ultra stops
1717 		 * streaming once it received a 0-byte OUT URB
1718 		 */
1719 		if (bytes == 0)
1720 			return;
1721 
1722 		spin_lock_irqsave(&ep->lock, flags);
1723 		if (ep->next_packet_queued >= ARRAY_SIZE(ep->next_packet)) {
1724 			spin_unlock_irqrestore(&ep->lock, flags);
1725 			usb_audio_err(ep->chip,
1726 				      "next package FIFO overflow EP 0x%x\n",
1727 				      ep->ep_num);
1728 			notify_xrun(ep);
1729 			return;
1730 		}
1731 
1732 		out_packet = next_packet_fifo_enqueue(ep);
1733 
1734 		/*
1735 		 * Iterate through the inbound packet and prepare the lengths
1736 		 * for the output packet. The OUT packet we are about to send
1737 		 * will have the same amount of payload bytes per stride as the
1738 		 * IN packet we just received. Since the actual size is scaled
1739 		 * by the stride, use the sender stride to calculate the length
1740 		 * in case the number of channels differ between the implicitly
1741 		 * fed-back endpoint and the synchronizing endpoint.
1742 		 */
1743 
1744 		out_packet->packets = in_ctx->packets;
1745 		for (i = 0; i < in_ctx->packets; i++) {
1746 			if (urb->iso_frame_desc[i].status == 0)
1747 				out_packet->packet_size[i] =
1748 					urb->iso_frame_desc[i].actual_length / sender->stride;
1749 			else
1750 				out_packet->packet_size[i] = 0;
1751 		}
1752 
1753 		spin_unlock_irqrestore(&ep->lock, flags);
1754 		snd_usb_queue_pending_output_urbs(ep, false);
1755 
1756 		return;
1757 	}
1758 
1759 	/*
1760 	 * process after playback sync complete
1761 	 *
1762 	 * Full speed devices report feedback values in 10.14 format as samples
1763 	 * per frame, high speed devices in 16.16 format as samples per
1764 	 * microframe.
1765 	 *
1766 	 * Because the Audio Class 1 spec was written before USB 2.0, many high
1767 	 * speed devices use a wrong interpretation, some others use an
1768 	 * entirely different format.
1769 	 *
1770 	 * Therefore, we cannot predict what format any particular device uses
1771 	 * and must detect it automatically.
1772 	 */
1773 
1774 	if (urb->iso_frame_desc[0].status != 0 ||
1775 	    urb->iso_frame_desc[0].actual_length < 3)
1776 		return;
1777 
1778 	f = le32_to_cpup(urb->transfer_buffer);
1779 	if (urb->iso_frame_desc[0].actual_length == 3)
1780 		f &= 0x00ffffff;
1781 	else
1782 		f &= 0x0fffffff;
1783 
1784 	if (f == 0)
1785 		return;
1786 
1787 	if (unlikely(sender->tenor_fb_quirk)) {
1788 		/*
1789 		 * Devices based on Tenor 8802 chipsets (TEAC UD-H01
1790 		 * and others) sometimes change the feedback value
1791 		 * by +/- 0x1.0000.
1792 		 */
1793 		if (f < ep->freqn - 0x8000)
1794 			f += 0xf000;
1795 		else if (f > ep->freqn + 0x8000)
1796 			f -= 0xf000;
1797 	} else if (unlikely(ep->freqshift == INT_MIN)) {
1798 		/*
1799 		 * The first time we see a feedback value, determine its format
1800 		 * by shifting it left or right until it matches the nominal
1801 		 * frequency value.  This assumes that the feedback does not
1802 		 * differ from the nominal value more than +50% or -25%.
1803 		 */
1804 		shift = 0;
1805 		while (f < ep->freqn - ep->freqn / 4) {
1806 			f <<= 1;
1807 			shift++;
1808 		}
1809 		while (f > ep->freqn + ep->freqn / 2) {
1810 			f >>= 1;
1811 			shift--;
1812 		}
1813 		ep->freqshift = shift;
1814 	} else if (ep->freqshift >= 0)
1815 		f <<= ep->freqshift;
1816 	else
1817 		f >>= -ep->freqshift;
1818 
1819 	if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1820 		/*
1821 		 * If the frequency looks valid, set it.
1822 		 * This value is referred to in prepare_playback_urb().
1823 		 */
1824 		spin_lock_irqsave(&ep->lock, flags);
1825 		ep->freqm = f;
1826 		spin_unlock_irqrestore(&ep->lock, flags);
1827 	} else {
1828 		/*
1829 		 * Out of range; maybe the shift value is wrong.
1830 		 * Reset it so that we autodetect again the next time.
1831 		 */
1832 		ep->freqshift = INT_MIN;
1833 	}
1834 }
1835 
1836