xref: /openbmc/linux/sound/usb/endpoint.c (revision fe7498ef)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  */
4 
5 #include <linux/gfp.h>
6 #include <linux/init.h>
7 #include <linux/ratelimit.h>
8 #include <linux/usb.h>
9 #include <linux/usb/audio.h>
10 #include <linux/slab.h>
11 
12 #include <sound/core.h>
13 #include <sound/pcm.h>
14 #include <sound/pcm_params.h>
15 
16 #include "usbaudio.h"
17 #include "helper.h"
18 #include "card.h"
19 #include "endpoint.h"
20 #include "pcm.h"
21 #include "clock.h"
22 #include "quirks.h"
23 
24 enum {
25 	EP_STATE_STOPPED,
26 	EP_STATE_RUNNING,
27 	EP_STATE_STOPPING,
28 };
29 
30 /* interface refcounting */
31 struct snd_usb_iface_ref {
32 	unsigned char iface;
33 	bool need_setup;
34 	int opened;
35 	struct list_head list;
36 };
37 
38 /*
39  * snd_usb_endpoint is a model that abstracts everything related to an
40  * USB endpoint and its streaming.
41  *
42  * There are functions to activate and deactivate the streaming URBs and
43  * optional callbacks to let the pcm logic handle the actual content of the
44  * packets for playback and record. Thus, the bus streaming and the audio
45  * handlers are fully decoupled.
46  *
47  * There are two different types of endpoints in audio applications.
48  *
49  * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
50  * inbound and outbound traffic.
51  *
52  * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
53  * expect the payload to carry Q10.14 / Q16.16 formatted sync information
54  * (3 or 4 bytes).
55  *
56  * Each endpoint has to be configured prior to being used by calling
57  * snd_usb_endpoint_set_params().
58  *
59  * The model incorporates a reference counting, so that multiple users
60  * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
61  * only the first user will effectively start the URBs, and only the last
62  * one to stop it will tear the URBs down again.
63  */
64 
65 /*
66  * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
67  * this will overflow at approx 524 kHz
68  */
69 static inline unsigned get_usb_full_speed_rate(unsigned int rate)
70 {
71 	return ((rate << 13) + 62) / 125;
72 }
73 
74 /*
75  * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
76  * this will overflow at approx 4 MHz
77  */
78 static inline unsigned get_usb_high_speed_rate(unsigned int rate)
79 {
80 	return ((rate << 10) + 62) / 125;
81 }
82 
83 /*
84  * release a urb data
85  */
86 static void release_urb_ctx(struct snd_urb_ctx *u)
87 {
88 	if (u->buffer_size)
89 		usb_free_coherent(u->ep->chip->dev, u->buffer_size,
90 				  u->urb->transfer_buffer,
91 				  u->urb->transfer_dma);
92 	usb_free_urb(u->urb);
93 	u->urb = NULL;
94 }
95 
96 static const char *usb_error_string(int err)
97 {
98 	switch (err) {
99 	case -ENODEV:
100 		return "no device";
101 	case -ENOENT:
102 		return "endpoint not enabled";
103 	case -EPIPE:
104 		return "endpoint stalled";
105 	case -ENOSPC:
106 		return "not enough bandwidth";
107 	case -ESHUTDOWN:
108 		return "device disabled";
109 	case -EHOSTUNREACH:
110 		return "device suspended";
111 	case -EINVAL:
112 	case -EAGAIN:
113 	case -EFBIG:
114 	case -EMSGSIZE:
115 		return "internal error";
116 	default:
117 		return "unknown error";
118 	}
119 }
120 
121 static inline bool ep_state_running(struct snd_usb_endpoint *ep)
122 {
123 	return atomic_read(&ep->state) == EP_STATE_RUNNING;
124 }
125 
126 static inline bool ep_state_update(struct snd_usb_endpoint *ep, int old, int new)
127 {
128 	return atomic_cmpxchg(&ep->state, old, new) == old;
129 }
130 
131 /**
132  * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
133  *
134  * @ep: The snd_usb_endpoint
135  *
136  * Determine whether an endpoint is driven by an implicit feedback
137  * data endpoint source.
138  */
139 int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
140 {
141 	return  ep->implicit_fb_sync && usb_pipeout(ep->pipe);
142 }
143 
144 /*
145  * Return the number of samples to be sent in the next packet
146  * for streaming based on information derived from sync endpoints
147  *
148  * This won't be used for implicit feedback which takes the packet size
149  * returned from the sync source
150  */
151 static int slave_next_packet_size(struct snd_usb_endpoint *ep,
152 				  unsigned int avail)
153 {
154 	unsigned long flags;
155 	unsigned int phase;
156 	int ret;
157 
158 	if (ep->fill_max)
159 		return ep->maxframesize;
160 
161 	spin_lock_irqsave(&ep->lock, flags);
162 	phase = (ep->phase & 0xffff) + (ep->freqm << ep->datainterval);
163 	ret = min(phase >> 16, ep->maxframesize);
164 	if (avail && ret >= avail)
165 		ret = -EAGAIN;
166 	else
167 		ep->phase = phase;
168 	spin_unlock_irqrestore(&ep->lock, flags);
169 
170 	return ret;
171 }
172 
173 /*
174  * Return the number of samples to be sent in the next packet
175  * for adaptive and synchronous endpoints
176  */
177 static int next_packet_size(struct snd_usb_endpoint *ep, unsigned int avail)
178 {
179 	unsigned int sample_accum;
180 	int ret;
181 
182 	if (ep->fill_max)
183 		return ep->maxframesize;
184 
185 	sample_accum = ep->sample_accum + ep->sample_rem;
186 	if (sample_accum >= ep->pps) {
187 		sample_accum -= ep->pps;
188 		ret = ep->packsize[1];
189 	} else {
190 		ret = ep->packsize[0];
191 	}
192 	if (avail && ret >= avail)
193 		ret = -EAGAIN;
194 	else
195 		ep->sample_accum = sample_accum;
196 
197 	return ret;
198 }
199 
200 /*
201  * snd_usb_endpoint_next_packet_size: Return the number of samples to be sent
202  * in the next packet
203  *
204  * If the size is equal or exceeds @avail, don't proceed but return -EAGAIN
205  * Exception: @avail = 0 for skipping the check.
206  */
207 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep,
208 				      struct snd_urb_ctx *ctx, int idx,
209 				      unsigned int avail)
210 {
211 	unsigned int packet;
212 
213 	packet = ctx->packet_size[idx];
214 	if (packet) {
215 		if (avail && packet >= avail)
216 			return -EAGAIN;
217 		return packet;
218 	}
219 
220 	if (ep->sync_source)
221 		return slave_next_packet_size(ep, avail);
222 	else
223 		return next_packet_size(ep, avail);
224 }
225 
226 static void call_retire_callback(struct snd_usb_endpoint *ep,
227 				 struct urb *urb)
228 {
229 	struct snd_usb_substream *data_subs;
230 
231 	data_subs = READ_ONCE(ep->data_subs);
232 	if (data_subs && ep->retire_data_urb)
233 		ep->retire_data_urb(data_subs, urb);
234 }
235 
236 static void retire_outbound_urb(struct snd_usb_endpoint *ep,
237 				struct snd_urb_ctx *urb_ctx)
238 {
239 	call_retire_callback(ep, urb_ctx->urb);
240 }
241 
242 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
243 				    struct snd_usb_endpoint *sender,
244 				    const struct urb *urb);
245 
246 static void retire_inbound_urb(struct snd_usb_endpoint *ep,
247 			       struct snd_urb_ctx *urb_ctx)
248 {
249 	struct urb *urb = urb_ctx->urb;
250 	struct snd_usb_endpoint *sync_sink;
251 
252 	if (unlikely(ep->skip_packets > 0)) {
253 		ep->skip_packets--;
254 		return;
255 	}
256 
257 	sync_sink = READ_ONCE(ep->sync_sink);
258 	if (sync_sink)
259 		snd_usb_handle_sync_urb(sync_sink, ep, urb);
260 
261 	call_retire_callback(ep, urb);
262 }
263 
264 static inline bool has_tx_length_quirk(struct snd_usb_audio *chip)
265 {
266 	return chip->quirk_flags & QUIRK_FLAG_TX_LENGTH;
267 }
268 
269 static void prepare_silent_urb(struct snd_usb_endpoint *ep,
270 			       struct snd_urb_ctx *ctx)
271 {
272 	struct urb *urb = ctx->urb;
273 	unsigned int offs = 0;
274 	unsigned int extra = 0;
275 	__le32 packet_length;
276 	int i;
277 
278 	/* For tx_length_quirk, put packet length at start of packet */
279 	if (has_tx_length_quirk(ep->chip))
280 		extra = sizeof(packet_length);
281 
282 	for (i = 0; i < ctx->packets; ++i) {
283 		unsigned int offset;
284 		unsigned int length;
285 		int counts;
286 
287 		counts = snd_usb_endpoint_next_packet_size(ep, ctx, i, 0);
288 		length = counts * ep->stride; /* number of silent bytes */
289 		offset = offs * ep->stride + extra * i;
290 		urb->iso_frame_desc[i].offset = offset;
291 		urb->iso_frame_desc[i].length = length + extra;
292 		if (extra) {
293 			packet_length = cpu_to_le32(length);
294 			memcpy(urb->transfer_buffer + offset,
295 			       &packet_length, sizeof(packet_length));
296 		}
297 		memset(urb->transfer_buffer + offset + extra,
298 		       ep->silence_value, length);
299 		offs += counts;
300 	}
301 
302 	urb->number_of_packets = ctx->packets;
303 	urb->transfer_buffer_length = offs * ep->stride + ctx->packets * extra;
304 	ctx->queued = 0;
305 }
306 
307 /*
308  * Prepare a PLAYBACK urb for submission to the bus.
309  */
310 static int prepare_outbound_urb(struct snd_usb_endpoint *ep,
311 				struct snd_urb_ctx *ctx,
312 				bool in_stream_lock)
313 {
314 	struct urb *urb = ctx->urb;
315 	unsigned char *cp = urb->transfer_buffer;
316 	struct snd_usb_substream *data_subs;
317 
318 	urb->dev = ep->chip->dev; /* we need to set this at each time */
319 
320 	switch (ep->type) {
321 	case SND_USB_ENDPOINT_TYPE_DATA:
322 		data_subs = READ_ONCE(ep->data_subs);
323 		if (data_subs && ep->prepare_data_urb)
324 			return ep->prepare_data_urb(data_subs, urb, in_stream_lock);
325 		/* no data provider, so send silence */
326 		prepare_silent_urb(ep, ctx);
327 		break;
328 
329 	case SND_USB_ENDPOINT_TYPE_SYNC:
330 		if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
331 			/*
332 			 * fill the length and offset of each urb descriptor.
333 			 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
334 			 */
335 			urb->iso_frame_desc[0].length = 4;
336 			urb->iso_frame_desc[0].offset = 0;
337 			cp[0] = ep->freqn;
338 			cp[1] = ep->freqn >> 8;
339 			cp[2] = ep->freqn >> 16;
340 			cp[3] = ep->freqn >> 24;
341 		} else {
342 			/*
343 			 * fill the length and offset of each urb descriptor.
344 			 * the fixed 10.14 frequency is passed through the pipe.
345 			 */
346 			urb->iso_frame_desc[0].length = 3;
347 			urb->iso_frame_desc[0].offset = 0;
348 			cp[0] = ep->freqn >> 2;
349 			cp[1] = ep->freqn >> 10;
350 			cp[2] = ep->freqn >> 18;
351 		}
352 
353 		break;
354 	}
355 	return 0;
356 }
357 
358 /*
359  * Prepare a CAPTURE or SYNC urb for submission to the bus.
360  */
361 static int prepare_inbound_urb(struct snd_usb_endpoint *ep,
362 			       struct snd_urb_ctx *urb_ctx)
363 {
364 	int i, offs;
365 	struct urb *urb = urb_ctx->urb;
366 
367 	urb->dev = ep->chip->dev; /* we need to set this at each time */
368 
369 	switch (ep->type) {
370 	case SND_USB_ENDPOINT_TYPE_DATA:
371 		offs = 0;
372 		for (i = 0; i < urb_ctx->packets; i++) {
373 			urb->iso_frame_desc[i].offset = offs;
374 			urb->iso_frame_desc[i].length = ep->curpacksize;
375 			offs += ep->curpacksize;
376 		}
377 
378 		urb->transfer_buffer_length = offs;
379 		urb->number_of_packets = urb_ctx->packets;
380 		break;
381 
382 	case SND_USB_ENDPOINT_TYPE_SYNC:
383 		urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
384 		urb->iso_frame_desc[0].offset = 0;
385 		break;
386 	}
387 	return 0;
388 }
389 
390 /* notify an error as XRUN to the assigned PCM data substream */
391 static void notify_xrun(struct snd_usb_endpoint *ep)
392 {
393 	struct snd_usb_substream *data_subs;
394 
395 	data_subs = READ_ONCE(ep->data_subs);
396 	if (data_subs && data_subs->pcm_substream)
397 		snd_pcm_stop_xrun(data_subs->pcm_substream);
398 }
399 
400 static struct snd_usb_packet_info *
401 next_packet_fifo_enqueue(struct snd_usb_endpoint *ep)
402 {
403 	struct snd_usb_packet_info *p;
404 
405 	p = ep->next_packet + (ep->next_packet_head + ep->next_packet_queued) %
406 		ARRAY_SIZE(ep->next_packet);
407 	ep->next_packet_queued++;
408 	return p;
409 }
410 
411 static struct snd_usb_packet_info *
412 next_packet_fifo_dequeue(struct snd_usb_endpoint *ep)
413 {
414 	struct snd_usb_packet_info *p;
415 
416 	p = ep->next_packet + ep->next_packet_head;
417 	ep->next_packet_head++;
418 	ep->next_packet_head %= ARRAY_SIZE(ep->next_packet);
419 	ep->next_packet_queued--;
420 	return p;
421 }
422 
423 static void push_back_to_ready_list(struct snd_usb_endpoint *ep,
424 				    struct snd_urb_ctx *ctx)
425 {
426 	unsigned long flags;
427 
428 	spin_lock_irqsave(&ep->lock, flags);
429 	list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
430 	spin_unlock_irqrestore(&ep->lock, flags);
431 }
432 
433 /*
434  * Send output urbs that have been prepared previously. URBs are dequeued
435  * from ep->ready_playback_urbs and in case there aren't any available
436  * or there are no packets that have been prepared, this function does
437  * nothing.
438  *
439  * The reason why the functionality of sending and preparing URBs is separated
440  * is that host controllers don't guarantee the order in which they return
441  * inbound and outbound packets to their submitters.
442  *
443  * This function is used both for implicit feedback endpoints and in low-
444  * latency playback mode.
445  */
446 void snd_usb_queue_pending_output_urbs(struct snd_usb_endpoint *ep,
447 				       bool in_stream_lock)
448 {
449 	bool implicit_fb = snd_usb_endpoint_implicit_feedback_sink(ep);
450 
451 	while (ep_state_running(ep)) {
452 
453 		unsigned long flags;
454 		struct snd_usb_packet_info *packet;
455 		struct snd_urb_ctx *ctx = NULL;
456 		int err, i;
457 
458 		spin_lock_irqsave(&ep->lock, flags);
459 		if ((!implicit_fb || ep->next_packet_queued > 0) &&
460 		    !list_empty(&ep->ready_playback_urbs)) {
461 			/* take URB out of FIFO */
462 			ctx = list_first_entry(&ep->ready_playback_urbs,
463 					       struct snd_urb_ctx, ready_list);
464 			list_del_init(&ctx->ready_list);
465 			if (implicit_fb)
466 				packet = next_packet_fifo_dequeue(ep);
467 		}
468 		spin_unlock_irqrestore(&ep->lock, flags);
469 
470 		if (ctx == NULL)
471 			return;
472 
473 		/* copy over the length information */
474 		if (implicit_fb) {
475 			for (i = 0; i < packet->packets; i++)
476 				ctx->packet_size[i] = packet->packet_size[i];
477 		}
478 
479 		/* call the data handler to fill in playback data */
480 		err = prepare_outbound_urb(ep, ctx, in_stream_lock);
481 		/* can be stopped during prepare callback */
482 		if (unlikely(!ep_state_running(ep)))
483 			break;
484 		if (err < 0) {
485 			/* push back to ready list again for -EAGAIN */
486 			if (err == -EAGAIN)
487 				push_back_to_ready_list(ep, ctx);
488 			else
489 				notify_xrun(ep);
490 			return;
491 		}
492 
493 		err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
494 		if (err < 0) {
495 			usb_audio_err(ep->chip,
496 				      "Unable to submit urb #%d: %d at %s\n",
497 				      ctx->index, err, __func__);
498 			notify_xrun(ep);
499 			return;
500 		}
501 
502 		set_bit(ctx->index, &ep->active_mask);
503 		atomic_inc(&ep->submitted_urbs);
504 	}
505 }
506 
507 /*
508  * complete callback for urbs
509  */
510 static void snd_complete_urb(struct urb *urb)
511 {
512 	struct snd_urb_ctx *ctx = urb->context;
513 	struct snd_usb_endpoint *ep = ctx->ep;
514 	int err;
515 
516 	if (unlikely(urb->status == -ENOENT ||		/* unlinked */
517 		     urb->status == -ENODEV ||		/* device removed */
518 		     urb->status == -ECONNRESET ||	/* unlinked */
519 		     urb->status == -ESHUTDOWN))	/* device disabled */
520 		goto exit_clear;
521 	/* device disconnected */
522 	if (unlikely(atomic_read(&ep->chip->shutdown)))
523 		goto exit_clear;
524 
525 	if (unlikely(!ep_state_running(ep)))
526 		goto exit_clear;
527 
528 	if (usb_pipeout(ep->pipe)) {
529 		retire_outbound_urb(ep, ctx);
530 		/* can be stopped during retire callback */
531 		if (unlikely(!ep_state_running(ep)))
532 			goto exit_clear;
533 
534 		/* in low-latency and implicit-feedback modes, push back the
535 		 * URB to ready list at first, then process as much as possible
536 		 */
537 		if (ep->lowlatency_playback ||
538 		     snd_usb_endpoint_implicit_feedback_sink(ep)) {
539 			push_back_to_ready_list(ep, ctx);
540 			clear_bit(ctx->index, &ep->active_mask);
541 			snd_usb_queue_pending_output_urbs(ep, false);
542 			atomic_dec(&ep->submitted_urbs); /* decrement at last */
543 			return;
544 		}
545 
546 		/* in non-lowlatency mode, no error handling for prepare */
547 		prepare_outbound_urb(ep, ctx, false);
548 		/* can be stopped during prepare callback */
549 		if (unlikely(!ep_state_running(ep)))
550 			goto exit_clear;
551 	} else {
552 		retire_inbound_urb(ep, ctx);
553 		/* can be stopped during retire callback */
554 		if (unlikely(!ep_state_running(ep)))
555 			goto exit_clear;
556 
557 		prepare_inbound_urb(ep, ctx);
558 	}
559 
560 	err = usb_submit_urb(urb, GFP_ATOMIC);
561 	if (err == 0)
562 		return;
563 
564 	usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
565 	notify_xrun(ep);
566 
567 exit_clear:
568 	clear_bit(ctx->index, &ep->active_mask);
569 	atomic_dec(&ep->submitted_urbs);
570 }
571 
572 /*
573  * Find or create a refcount object for the given interface
574  *
575  * The objects are released altogether in snd_usb_endpoint_free_all()
576  */
577 static struct snd_usb_iface_ref *
578 iface_ref_find(struct snd_usb_audio *chip, int iface)
579 {
580 	struct snd_usb_iface_ref *ip;
581 
582 	list_for_each_entry(ip, &chip->iface_ref_list, list)
583 		if (ip->iface == iface)
584 			return ip;
585 
586 	ip = kzalloc(sizeof(*ip), GFP_KERNEL);
587 	if (!ip)
588 		return NULL;
589 	ip->iface = iface;
590 	list_add_tail(&ip->list, &chip->iface_ref_list);
591 	return ip;
592 }
593 
594 /*
595  * Get the existing endpoint object corresponding EP
596  * Returns NULL if not present.
597  */
598 struct snd_usb_endpoint *
599 snd_usb_get_endpoint(struct snd_usb_audio *chip, int ep_num)
600 {
601 	struct snd_usb_endpoint *ep;
602 
603 	list_for_each_entry(ep, &chip->ep_list, list) {
604 		if (ep->ep_num == ep_num)
605 			return ep;
606 	}
607 
608 	return NULL;
609 }
610 
611 #define ep_type_name(type) \
612 	(type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync")
613 
614 /**
615  * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
616  *
617  * @chip: The chip
618  * @ep_num: The number of the endpoint to use
619  * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
620  *
621  * If the requested endpoint has not been added to the given chip before,
622  * a new instance is created.
623  *
624  * Returns zero on success or a negative error code.
625  *
626  * New endpoints will be added to chip->ep_list and freed by
627  * calling snd_usb_endpoint_free_all().
628  *
629  * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
630  * bNumEndpoints > 1 beforehand.
631  */
632 int snd_usb_add_endpoint(struct snd_usb_audio *chip, int ep_num, int type)
633 {
634 	struct snd_usb_endpoint *ep;
635 	bool is_playback;
636 
637 	ep = snd_usb_get_endpoint(chip, ep_num);
638 	if (ep)
639 		return 0;
640 
641 	usb_audio_dbg(chip, "Creating new %s endpoint #%x\n",
642 		      ep_type_name(type),
643 		      ep_num);
644 	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
645 	if (!ep)
646 		return -ENOMEM;
647 
648 	ep->chip = chip;
649 	spin_lock_init(&ep->lock);
650 	ep->type = type;
651 	ep->ep_num = ep_num;
652 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
653 	atomic_set(&ep->submitted_urbs, 0);
654 
655 	is_playback = ((ep_num & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT);
656 	ep_num &= USB_ENDPOINT_NUMBER_MASK;
657 	if (is_playback)
658 		ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
659 	else
660 		ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
661 
662 	list_add_tail(&ep->list, &chip->ep_list);
663 	return 0;
664 }
665 
666 /* Set up syncinterval and maxsyncsize for a sync EP */
667 static void endpoint_set_syncinterval(struct snd_usb_audio *chip,
668 				      struct snd_usb_endpoint *ep)
669 {
670 	struct usb_host_interface *alts;
671 	struct usb_endpoint_descriptor *desc;
672 
673 	alts = snd_usb_get_host_interface(chip, ep->iface, ep->altsetting);
674 	if (!alts)
675 		return;
676 
677 	desc = get_endpoint(alts, ep->ep_idx);
678 	if (desc->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
679 	    desc->bRefresh >= 1 && desc->bRefresh <= 9)
680 		ep->syncinterval = desc->bRefresh;
681 	else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
682 		ep->syncinterval = 1;
683 	else if (desc->bInterval >= 1 && desc->bInterval <= 16)
684 		ep->syncinterval = desc->bInterval - 1;
685 	else
686 		ep->syncinterval = 3;
687 
688 	ep->syncmaxsize = le16_to_cpu(desc->wMaxPacketSize);
689 }
690 
691 static bool endpoint_compatible(struct snd_usb_endpoint *ep,
692 				const struct audioformat *fp,
693 				const struct snd_pcm_hw_params *params)
694 {
695 	if (!ep->opened)
696 		return false;
697 	if (ep->cur_audiofmt != fp)
698 		return false;
699 	if (ep->cur_rate != params_rate(params) ||
700 	    ep->cur_format != params_format(params) ||
701 	    ep->cur_period_frames != params_period_size(params) ||
702 	    ep->cur_buffer_periods != params_periods(params))
703 		return false;
704 	return true;
705 }
706 
707 /*
708  * Check whether the given fp and hw params are compatible with the current
709  * setup of the target EP for implicit feedback sync
710  */
711 bool snd_usb_endpoint_compatible(struct snd_usb_audio *chip,
712 				 struct snd_usb_endpoint *ep,
713 				 const struct audioformat *fp,
714 				 const struct snd_pcm_hw_params *params)
715 {
716 	bool ret;
717 
718 	mutex_lock(&chip->mutex);
719 	ret = endpoint_compatible(ep, fp, params);
720 	mutex_unlock(&chip->mutex);
721 	return ret;
722 }
723 
724 /*
725  * snd_usb_endpoint_open: Open the endpoint
726  *
727  * Called from hw_params to assign the endpoint to the substream.
728  * It's reference-counted, and only the first opener is allowed to set up
729  * arbitrary parameters.  The later opener must be compatible with the
730  * former opened parameters.
731  * The endpoint needs to be closed via snd_usb_endpoint_close() later.
732  *
733  * Note that this function doesn't configure the endpoint.  The substream
734  * needs to set it up later via snd_usb_endpoint_configure().
735  */
736 struct snd_usb_endpoint *
737 snd_usb_endpoint_open(struct snd_usb_audio *chip,
738 		      const struct audioformat *fp,
739 		      const struct snd_pcm_hw_params *params,
740 		      bool is_sync_ep)
741 {
742 	struct snd_usb_endpoint *ep;
743 	int ep_num = is_sync_ep ? fp->sync_ep : fp->endpoint;
744 
745 	mutex_lock(&chip->mutex);
746 	ep = snd_usb_get_endpoint(chip, ep_num);
747 	if (!ep) {
748 		usb_audio_err(chip, "Cannot find EP 0x%x to open\n", ep_num);
749 		goto unlock;
750 	}
751 
752 	if (!ep->opened) {
753 		if (is_sync_ep) {
754 			ep->iface = fp->sync_iface;
755 			ep->altsetting = fp->sync_altsetting;
756 			ep->ep_idx = fp->sync_ep_idx;
757 		} else {
758 			ep->iface = fp->iface;
759 			ep->altsetting = fp->altsetting;
760 			ep->ep_idx = fp->ep_idx;
761 		}
762 		usb_audio_dbg(chip, "Open EP 0x%x, iface=%d:%d, idx=%d\n",
763 			      ep_num, ep->iface, ep->altsetting, ep->ep_idx);
764 
765 		ep->iface_ref = iface_ref_find(chip, ep->iface);
766 		if (!ep->iface_ref) {
767 			ep = NULL;
768 			goto unlock;
769 		}
770 
771 		ep->cur_audiofmt = fp;
772 		ep->cur_channels = fp->channels;
773 		ep->cur_rate = params_rate(params);
774 		ep->cur_format = params_format(params);
775 		ep->cur_frame_bytes = snd_pcm_format_physical_width(ep->cur_format) *
776 			ep->cur_channels / 8;
777 		ep->cur_period_frames = params_period_size(params);
778 		ep->cur_period_bytes = ep->cur_period_frames * ep->cur_frame_bytes;
779 		ep->cur_buffer_periods = params_periods(params);
780 		ep->cur_clock = fp->clock;
781 
782 		if (ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
783 			endpoint_set_syncinterval(chip, ep);
784 
785 		ep->implicit_fb_sync = fp->implicit_fb;
786 		ep->need_setup = true;
787 
788 		usb_audio_dbg(chip, "  channels=%d, rate=%d, format=%s, period_bytes=%d, periods=%d, implicit_fb=%d\n",
789 			      ep->cur_channels, ep->cur_rate,
790 			      snd_pcm_format_name(ep->cur_format),
791 			      ep->cur_period_bytes, ep->cur_buffer_periods,
792 			      ep->implicit_fb_sync);
793 
794 	} else {
795 		if (WARN_ON(!ep->iface_ref)) {
796 			ep = NULL;
797 			goto unlock;
798 		}
799 
800 		if (!endpoint_compatible(ep, fp, params)) {
801 			usb_audio_err(chip, "Incompatible EP setup for 0x%x\n",
802 				      ep_num);
803 			ep = NULL;
804 			goto unlock;
805 		}
806 
807 		usb_audio_dbg(chip, "Reopened EP 0x%x (count %d)\n",
808 			      ep_num, ep->opened);
809 	}
810 
811 	if (!ep->iface_ref->opened++)
812 		ep->iface_ref->need_setup = true;
813 
814 	ep->opened++;
815 
816  unlock:
817 	mutex_unlock(&chip->mutex);
818 	return ep;
819 }
820 
821 /*
822  * snd_usb_endpoint_set_sync: Link data and sync endpoints
823  *
824  * Pass NULL to sync_ep to unlink again
825  */
826 void snd_usb_endpoint_set_sync(struct snd_usb_audio *chip,
827 			       struct snd_usb_endpoint *data_ep,
828 			       struct snd_usb_endpoint *sync_ep)
829 {
830 	data_ep->sync_source = sync_ep;
831 }
832 
833 /*
834  * Set data endpoint callbacks and the assigned data stream
835  *
836  * Called at PCM trigger and cleanups.
837  * Pass NULL to deactivate each callback.
838  */
839 void snd_usb_endpoint_set_callback(struct snd_usb_endpoint *ep,
840 				   int (*prepare)(struct snd_usb_substream *subs,
841 						  struct urb *urb,
842 						  bool in_stream_lock),
843 				   void (*retire)(struct snd_usb_substream *subs,
844 						  struct urb *urb),
845 				   struct snd_usb_substream *data_subs)
846 {
847 	ep->prepare_data_urb = prepare;
848 	ep->retire_data_urb = retire;
849 	if (data_subs)
850 		ep->lowlatency_playback = data_subs->lowlatency_playback;
851 	else
852 		ep->lowlatency_playback = false;
853 	WRITE_ONCE(ep->data_subs, data_subs);
854 }
855 
856 static int endpoint_set_interface(struct snd_usb_audio *chip,
857 				  struct snd_usb_endpoint *ep,
858 				  bool set)
859 {
860 	int altset = set ? ep->altsetting : 0;
861 	int err;
862 
863 	usb_audio_dbg(chip, "Setting usb interface %d:%d for EP 0x%x\n",
864 		      ep->iface, altset, ep->ep_num);
865 	err = usb_set_interface(chip->dev, ep->iface, altset);
866 	if (err < 0) {
867 		usb_audio_err(chip, "%d:%d: usb_set_interface failed (%d)\n",
868 			      ep->iface, altset, err);
869 		return err;
870 	}
871 
872 	if (chip->quirk_flags & QUIRK_FLAG_IFACE_DELAY)
873 		msleep(50);
874 	return 0;
875 }
876 
877 /*
878  * snd_usb_endpoint_close: Close the endpoint
879  *
880  * Unreference the already opened endpoint via snd_usb_endpoint_open().
881  */
882 void snd_usb_endpoint_close(struct snd_usb_audio *chip,
883 			    struct snd_usb_endpoint *ep)
884 {
885 	mutex_lock(&chip->mutex);
886 	usb_audio_dbg(chip, "Closing EP 0x%x (count %d)\n",
887 		      ep->ep_num, ep->opened);
888 
889 	if (!--ep->iface_ref->opened)
890 		endpoint_set_interface(chip, ep, false);
891 
892 	if (!--ep->opened) {
893 		ep->iface = 0;
894 		ep->altsetting = 0;
895 		ep->cur_audiofmt = NULL;
896 		ep->cur_rate = 0;
897 		ep->cur_clock = 0;
898 		ep->iface_ref = NULL;
899 		usb_audio_dbg(chip, "EP 0x%x closed\n", ep->ep_num);
900 	}
901 	mutex_unlock(&chip->mutex);
902 }
903 
904 /* Prepare for suspening EP, called from the main suspend handler */
905 void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep)
906 {
907 	ep->need_setup = true;
908 	if (ep->iface_ref)
909 		ep->iface_ref->need_setup = true;
910 }
911 
912 /*
913  *  wait until all urbs are processed.
914  */
915 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
916 {
917 	unsigned long end_time = jiffies + msecs_to_jiffies(1000);
918 	int alive;
919 
920 	if (atomic_read(&ep->state) != EP_STATE_STOPPING)
921 		return 0;
922 
923 	do {
924 		alive = atomic_read(&ep->submitted_urbs);
925 		if (!alive)
926 			break;
927 
928 		schedule_timeout_uninterruptible(1);
929 	} while (time_before(jiffies, end_time));
930 
931 	if (alive)
932 		usb_audio_err(ep->chip,
933 			"timeout: still %d active urbs on EP #%x\n",
934 			alive, ep->ep_num);
935 
936 	if (ep_state_update(ep, EP_STATE_STOPPING, EP_STATE_STOPPED)) {
937 		ep->sync_sink = NULL;
938 		snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
939 	}
940 
941 	return 0;
942 }
943 
944 /* sync the pending stop operation;
945  * this function itself doesn't trigger the stop operation
946  */
947 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
948 {
949 	if (ep)
950 		wait_clear_urbs(ep);
951 }
952 
953 /*
954  * Stop active urbs
955  *
956  * This function moves the EP to STOPPING state if it's being RUNNING.
957  */
958 static int stop_urbs(struct snd_usb_endpoint *ep, bool force, bool keep_pending)
959 {
960 	unsigned int i;
961 	unsigned long flags;
962 
963 	if (!force && atomic_read(&ep->running))
964 		return -EBUSY;
965 
966 	if (!ep_state_update(ep, EP_STATE_RUNNING, EP_STATE_STOPPING))
967 		return 0;
968 
969 	spin_lock_irqsave(&ep->lock, flags);
970 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
971 	ep->next_packet_head = 0;
972 	ep->next_packet_queued = 0;
973 	spin_unlock_irqrestore(&ep->lock, flags);
974 
975 	if (keep_pending)
976 		return 0;
977 
978 	for (i = 0; i < ep->nurbs; i++) {
979 		if (test_bit(i, &ep->active_mask)) {
980 			if (!test_and_set_bit(i, &ep->unlink_mask)) {
981 				struct urb *u = ep->urb[i].urb;
982 				usb_unlink_urb(u);
983 			}
984 		}
985 	}
986 
987 	return 0;
988 }
989 
990 /*
991  * release an endpoint's urbs
992  */
993 static int release_urbs(struct snd_usb_endpoint *ep, bool force)
994 {
995 	int i, err;
996 
997 	/* route incoming urbs to nirvana */
998 	snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
999 
1000 	/* stop and unlink urbs */
1001 	err = stop_urbs(ep, force, false);
1002 	if (err)
1003 		return err;
1004 
1005 	wait_clear_urbs(ep);
1006 
1007 	for (i = 0; i < ep->nurbs; i++)
1008 		release_urb_ctx(&ep->urb[i]);
1009 
1010 	usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
1011 			  ep->syncbuf, ep->sync_dma);
1012 
1013 	ep->syncbuf = NULL;
1014 	ep->nurbs = 0;
1015 	return 0;
1016 }
1017 
1018 /*
1019  * configure a data endpoint
1020  */
1021 static int data_ep_set_params(struct snd_usb_endpoint *ep)
1022 {
1023 	struct snd_usb_audio *chip = ep->chip;
1024 	unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
1025 	unsigned int max_packs_per_period, urbs_per_period, urb_packs;
1026 	unsigned int max_urbs, i;
1027 	const struct audioformat *fmt = ep->cur_audiofmt;
1028 	int frame_bits = ep->cur_frame_bytes * 8;
1029 	int tx_length_quirk = (has_tx_length_quirk(chip) &&
1030 			       usb_pipeout(ep->pipe));
1031 
1032 	usb_audio_dbg(chip, "Setting params for data EP 0x%x, pipe 0x%x\n",
1033 		      ep->ep_num, ep->pipe);
1034 
1035 	if (ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
1036 		/*
1037 		 * When operating in DSD DOP mode, the size of a sample frame
1038 		 * in hardware differs from the actual physical format width
1039 		 * because we need to make room for the DOP markers.
1040 		 */
1041 		frame_bits += ep->cur_channels << 3;
1042 	}
1043 
1044 	ep->datainterval = fmt->datainterval;
1045 	ep->stride = frame_bits >> 3;
1046 
1047 	switch (ep->cur_format) {
1048 	case SNDRV_PCM_FORMAT_U8:
1049 		ep->silence_value = 0x80;
1050 		break;
1051 	case SNDRV_PCM_FORMAT_DSD_U8:
1052 	case SNDRV_PCM_FORMAT_DSD_U16_LE:
1053 	case SNDRV_PCM_FORMAT_DSD_U32_LE:
1054 	case SNDRV_PCM_FORMAT_DSD_U16_BE:
1055 	case SNDRV_PCM_FORMAT_DSD_U32_BE:
1056 		ep->silence_value = 0x69;
1057 		break;
1058 	default:
1059 		ep->silence_value = 0;
1060 	}
1061 
1062 	/* assume max. frequency is 50% higher than nominal */
1063 	ep->freqmax = ep->freqn + (ep->freqn >> 1);
1064 	/* Round up freqmax to nearest integer in order to calculate maximum
1065 	 * packet size, which must represent a whole number of frames.
1066 	 * This is accomplished by adding 0x0.ffff before converting the
1067 	 * Q16.16 format into integer.
1068 	 * In order to accurately calculate the maximum packet size when
1069 	 * the data interval is more than 1 (i.e. ep->datainterval > 0),
1070 	 * multiply by the data interval prior to rounding. For instance,
1071 	 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
1072 	 * frames with a data interval of 1, but 11 (10.25) frames with a
1073 	 * data interval of 2.
1074 	 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
1075 	 * maximum datainterval value of 3, at USB full speed, higher for
1076 	 * USB high speed, noting that ep->freqmax is in units of
1077 	 * frames per packet in Q16.16 format.)
1078 	 */
1079 	maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
1080 			 (frame_bits >> 3);
1081 	if (tx_length_quirk)
1082 		maxsize += sizeof(__le32); /* Space for length descriptor */
1083 	/* but wMaxPacketSize might reduce this */
1084 	if (ep->maxpacksize && ep->maxpacksize < maxsize) {
1085 		/* whatever fits into a max. size packet */
1086 		unsigned int data_maxsize = maxsize = ep->maxpacksize;
1087 
1088 		if (tx_length_quirk)
1089 			/* Need to remove the length descriptor to calc freq */
1090 			data_maxsize -= sizeof(__le32);
1091 		ep->freqmax = (data_maxsize / (frame_bits >> 3))
1092 				<< (16 - ep->datainterval);
1093 	}
1094 
1095 	if (ep->fill_max)
1096 		ep->curpacksize = ep->maxpacksize;
1097 	else
1098 		ep->curpacksize = maxsize;
1099 
1100 	if (snd_usb_get_speed(chip->dev) != USB_SPEED_FULL) {
1101 		packs_per_ms = 8 >> ep->datainterval;
1102 		max_packs_per_urb = MAX_PACKS_HS;
1103 	} else {
1104 		packs_per_ms = 1;
1105 		max_packs_per_urb = MAX_PACKS;
1106 	}
1107 	if (ep->sync_source && !ep->implicit_fb_sync)
1108 		max_packs_per_urb = min(max_packs_per_urb,
1109 					1U << ep->sync_source->syncinterval);
1110 	max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
1111 
1112 	/*
1113 	 * Capture endpoints need to use small URBs because there's no way
1114 	 * to tell in advance where the next period will end, and we don't
1115 	 * want the next URB to complete much after the period ends.
1116 	 *
1117 	 * Playback endpoints with implicit sync much use the same parameters
1118 	 * as their corresponding capture endpoint.
1119 	 */
1120 	if (usb_pipein(ep->pipe) || ep->implicit_fb_sync) {
1121 
1122 		urb_packs = packs_per_ms;
1123 		/*
1124 		 * Wireless devices can poll at a max rate of once per 4ms.
1125 		 * For dataintervals less than 5, increase the packet count to
1126 		 * allow the host controller to use bursting to fill in the
1127 		 * gaps.
1128 		 */
1129 		if (snd_usb_get_speed(chip->dev) == USB_SPEED_WIRELESS) {
1130 			int interval = ep->datainterval;
1131 			while (interval < 5) {
1132 				urb_packs <<= 1;
1133 				++interval;
1134 			}
1135 		}
1136 		/* make capture URBs <= 1 ms and smaller than a period */
1137 		urb_packs = min(max_packs_per_urb, urb_packs);
1138 		while (urb_packs > 1 && urb_packs * maxsize >= ep->cur_period_bytes)
1139 			urb_packs >>= 1;
1140 		ep->nurbs = MAX_URBS;
1141 
1142 	/*
1143 	 * Playback endpoints without implicit sync are adjusted so that
1144 	 * a period fits as evenly as possible in the smallest number of
1145 	 * URBs.  The total number of URBs is adjusted to the size of the
1146 	 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
1147 	 */
1148 	} else {
1149 		/* determine how small a packet can be */
1150 		minsize = (ep->freqn >> (16 - ep->datainterval)) *
1151 				(frame_bits >> 3);
1152 		/* with sync from device, assume it can be 12% lower */
1153 		if (ep->sync_source)
1154 			minsize -= minsize >> 3;
1155 		minsize = max(minsize, 1u);
1156 
1157 		/* how many packets will contain an entire ALSA period? */
1158 		max_packs_per_period = DIV_ROUND_UP(ep->cur_period_bytes, minsize);
1159 
1160 		/* how many URBs will contain a period? */
1161 		urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
1162 				max_packs_per_urb);
1163 		/* how many packets are needed in each URB? */
1164 		urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
1165 
1166 		/* limit the number of frames in a single URB */
1167 		ep->max_urb_frames = DIV_ROUND_UP(ep->cur_period_frames,
1168 						  urbs_per_period);
1169 
1170 		/* try to use enough URBs to contain an entire ALSA buffer */
1171 		max_urbs = min((unsigned) MAX_URBS,
1172 				MAX_QUEUE * packs_per_ms / urb_packs);
1173 		ep->nurbs = min(max_urbs, urbs_per_period * ep->cur_buffer_periods);
1174 	}
1175 
1176 	/* allocate and initialize data urbs */
1177 	for (i = 0; i < ep->nurbs; i++) {
1178 		struct snd_urb_ctx *u = &ep->urb[i];
1179 		u->index = i;
1180 		u->ep = ep;
1181 		u->packets = urb_packs;
1182 		u->buffer_size = maxsize * u->packets;
1183 
1184 		if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
1185 			u->packets++; /* for transfer delimiter */
1186 		u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
1187 		if (!u->urb)
1188 			goto out_of_memory;
1189 
1190 		u->urb->transfer_buffer =
1191 			usb_alloc_coherent(chip->dev, u->buffer_size,
1192 					   GFP_KERNEL, &u->urb->transfer_dma);
1193 		if (!u->urb->transfer_buffer)
1194 			goto out_of_memory;
1195 		u->urb->pipe = ep->pipe;
1196 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1197 		u->urb->interval = 1 << ep->datainterval;
1198 		u->urb->context = u;
1199 		u->urb->complete = snd_complete_urb;
1200 		INIT_LIST_HEAD(&u->ready_list);
1201 	}
1202 
1203 	return 0;
1204 
1205 out_of_memory:
1206 	release_urbs(ep, false);
1207 	return -ENOMEM;
1208 }
1209 
1210 /*
1211  * configure a sync endpoint
1212  */
1213 static int sync_ep_set_params(struct snd_usb_endpoint *ep)
1214 {
1215 	struct snd_usb_audio *chip = ep->chip;
1216 	int i;
1217 
1218 	usb_audio_dbg(chip, "Setting params for sync EP 0x%x, pipe 0x%x\n",
1219 		      ep->ep_num, ep->pipe);
1220 
1221 	ep->syncbuf = usb_alloc_coherent(chip->dev, SYNC_URBS * 4,
1222 					 GFP_KERNEL, &ep->sync_dma);
1223 	if (!ep->syncbuf)
1224 		return -ENOMEM;
1225 
1226 	for (i = 0; i < SYNC_URBS; i++) {
1227 		struct snd_urb_ctx *u = &ep->urb[i];
1228 		u->index = i;
1229 		u->ep = ep;
1230 		u->packets = 1;
1231 		u->urb = usb_alloc_urb(1, GFP_KERNEL);
1232 		if (!u->urb)
1233 			goto out_of_memory;
1234 		u->urb->transfer_buffer = ep->syncbuf + i * 4;
1235 		u->urb->transfer_dma = ep->sync_dma + i * 4;
1236 		u->urb->transfer_buffer_length = 4;
1237 		u->urb->pipe = ep->pipe;
1238 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1239 		u->urb->number_of_packets = 1;
1240 		u->urb->interval = 1 << ep->syncinterval;
1241 		u->urb->context = u;
1242 		u->urb->complete = snd_complete_urb;
1243 	}
1244 
1245 	ep->nurbs = SYNC_URBS;
1246 
1247 	return 0;
1248 
1249 out_of_memory:
1250 	release_urbs(ep, false);
1251 	return -ENOMEM;
1252 }
1253 
1254 /*
1255  * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
1256  *
1257  * Determine the number of URBs to be used on this endpoint.
1258  * An endpoint must be configured before it can be started.
1259  * An endpoint that is already running can not be reconfigured.
1260  */
1261 static int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
1262 				       struct snd_usb_endpoint *ep)
1263 {
1264 	const struct audioformat *fmt = ep->cur_audiofmt;
1265 	int err;
1266 
1267 	/* release old buffers, if any */
1268 	err = release_urbs(ep, false);
1269 	if (err < 0)
1270 		return err;
1271 
1272 	ep->datainterval = fmt->datainterval;
1273 	ep->maxpacksize = fmt->maxpacksize;
1274 	ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
1275 
1276 	if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) {
1277 		ep->freqn = get_usb_full_speed_rate(ep->cur_rate);
1278 		ep->pps = 1000 >> ep->datainterval;
1279 	} else {
1280 		ep->freqn = get_usb_high_speed_rate(ep->cur_rate);
1281 		ep->pps = 8000 >> ep->datainterval;
1282 	}
1283 
1284 	ep->sample_rem = ep->cur_rate % ep->pps;
1285 	ep->packsize[0] = ep->cur_rate / ep->pps;
1286 	ep->packsize[1] = (ep->cur_rate + (ep->pps - 1)) / ep->pps;
1287 
1288 	/* calculate the frequency in 16.16 format */
1289 	ep->freqm = ep->freqn;
1290 	ep->freqshift = INT_MIN;
1291 
1292 	ep->phase = 0;
1293 
1294 	switch (ep->type) {
1295 	case  SND_USB_ENDPOINT_TYPE_DATA:
1296 		err = data_ep_set_params(ep);
1297 		break;
1298 	case  SND_USB_ENDPOINT_TYPE_SYNC:
1299 		err = sync_ep_set_params(ep);
1300 		break;
1301 	default:
1302 		err = -EINVAL;
1303 	}
1304 
1305 	usb_audio_dbg(chip, "Set up %d URBS, ret=%d\n", ep->nurbs, err);
1306 
1307 	if (err < 0)
1308 		return err;
1309 
1310 	/* some unit conversions in runtime */
1311 	ep->maxframesize = ep->maxpacksize / ep->cur_frame_bytes;
1312 	ep->curframesize = ep->curpacksize / ep->cur_frame_bytes;
1313 
1314 	return 0;
1315 }
1316 
1317 /*
1318  * snd_usb_endpoint_configure: Configure the endpoint
1319  *
1320  * This function sets up the EP to be fully usable state.
1321  * It's called either from hw_params or prepare callback.
1322  * The function checks need_setup flag, and performs nothing unless needed,
1323  * so it's safe to call this multiple times.
1324  *
1325  * This returns zero if unchanged, 1 if the configuration has changed,
1326  * or a negative error code.
1327  */
1328 int snd_usb_endpoint_configure(struct snd_usb_audio *chip,
1329 			       struct snd_usb_endpoint *ep)
1330 {
1331 	bool iface_first;
1332 	int err = 0;
1333 
1334 	mutex_lock(&chip->mutex);
1335 	if (WARN_ON(!ep->iface_ref))
1336 		goto unlock;
1337 	if (!ep->need_setup)
1338 		goto unlock;
1339 
1340 	/* If the interface has been already set up, just set EP parameters */
1341 	if (!ep->iface_ref->need_setup) {
1342 		/* sample rate setup of UAC1 is per endpoint, and we need
1343 		 * to update at each EP configuration
1344 		 */
1345 		if (ep->cur_audiofmt->protocol == UAC_VERSION_1) {
1346 			err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt,
1347 						       ep->cur_rate);
1348 			if (err < 0)
1349 				goto unlock;
1350 		}
1351 		err = snd_usb_endpoint_set_params(chip, ep);
1352 		if (err < 0)
1353 			goto unlock;
1354 		goto done;
1355 	}
1356 
1357 	/* Need to deselect altsetting at first */
1358 	endpoint_set_interface(chip, ep, false);
1359 
1360 	/* Some UAC1 devices (e.g. Yamaha THR10) need the host interface
1361 	 * to be set up before parameter setups
1362 	 */
1363 	iface_first = ep->cur_audiofmt->protocol == UAC_VERSION_1;
1364 	/* Workaround for devices that require the interface setup at first like UAC1 */
1365 	if (chip->quirk_flags & QUIRK_FLAG_SET_IFACE_FIRST)
1366 		iface_first = true;
1367 	if (iface_first) {
1368 		err = endpoint_set_interface(chip, ep, true);
1369 		if (err < 0)
1370 			goto unlock;
1371 	}
1372 
1373 	err = snd_usb_init_pitch(chip, ep->cur_audiofmt);
1374 	if (err < 0)
1375 		goto unlock;
1376 
1377 	err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, ep->cur_rate);
1378 	if (err < 0)
1379 		goto unlock;
1380 
1381 	err = snd_usb_endpoint_set_params(chip, ep);
1382 	if (err < 0)
1383 		goto unlock;
1384 
1385 	err = snd_usb_select_mode_quirk(chip, ep->cur_audiofmt);
1386 	if (err < 0)
1387 		goto unlock;
1388 
1389 	/* for UAC2/3, enable the interface altset here at last */
1390 	if (!iface_first) {
1391 		err = endpoint_set_interface(chip, ep, true);
1392 		if (err < 0)
1393 			goto unlock;
1394 	}
1395 
1396 	ep->iface_ref->need_setup = false;
1397 
1398  done:
1399 	ep->need_setup = false;
1400 	err = 1;
1401 
1402 unlock:
1403 	mutex_unlock(&chip->mutex);
1404 	return err;
1405 }
1406 
1407 /* get the current rate set to the given clock by any endpoint */
1408 int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock)
1409 {
1410 	struct snd_usb_endpoint *ep;
1411 	int rate = 0;
1412 
1413 	if (!clock)
1414 		return 0;
1415 	mutex_lock(&chip->mutex);
1416 	list_for_each_entry(ep, &chip->ep_list, list) {
1417 		if (ep->cur_clock == clock && ep->cur_rate) {
1418 			rate = ep->cur_rate;
1419 			break;
1420 		}
1421 	}
1422 	mutex_unlock(&chip->mutex);
1423 	return rate;
1424 }
1425 
1426 /**
1427  * snd_usb_endpoint_start: start an snd_usb_endpoint
1428  *
1429  * @ep: the endpoint to start
1430  *
1431  * A call to this function will increment the running count of the endpoint.
1432  * In case it is not already running, the URBs for this endpoint will be
1433  * submitted. Otherwise, this function does nothing.
1434  *
1435  * Must be balanced to calls of snd_usb_endpoint_stop().
1436  *
1437  * Returns an error if the URB submission failed, 0 in all other cases.
1438  */
1439 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
1440 {
1441 	bool is_playback = usb_pipeout(ep->pipe);
1442 	int err;
1443 	unsigned int i;
1444 
1445 	if (atomic_read(&ep->chip->shutdown))
1446 		return -EBADFD;
1447 
1448 	if (ep->sync_source)
1449 		WRITE_ONCE(ep->sync_source->sync_sink, ep);
1450 
1451 	usb_audio_dbg(ep->chip, "Starting %s EP 0x%x (running %d)\n",
1452 		      ep_type_name(ep->type), ep->ep_num,
1453 		      atomic_read(&ep->running));
1454 
1455 	/* already running? */
1456 	if (atomic_inc_return(&ep->running) != 1)
1457 		return 0;
1458 
1459 	ep->active_mask = 0;
1460 	ep->unlink_mask = 0;
1461 	ep->phase = 0;
1462 	ep->sample_accum = 0;
1463 
1464 	snd_usb_endpoint_start_quirk(ep);
1465 
1466 	/*
1467 	 * If this endpoint has a data endpoint as implicit feedback source,
1468 	 * don't start the urbs here. Instead, mark them all as available,
1469 	 * wait for the record urbs to return and queue the playback urbs
1470 	 * from that context.
1471 	 */
1472 
1473 	if (!ep_state_update(ep, EP_STATE_STOPPED, EP_STATE_RUNNING))
1474 		goto __error;
1475 
1476 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1477 	    !(ep->chip->quirk_flags & QUIRK_FLAG_PLAYBACK_FIRST)) {
1478 		usb_audio_dbg(ep->chip, "No URB submission due to implicit fb sync\n");
1479 		i = 0;
1480 		goto fill_rest;
1481 	}
1482 
1483 	for (i = 0; i < ep->nurbs; i++) {
1484 		struct urb *urb = ep->urb[i].urb;
1485 
1486 		if (snd_BUG_ON(!urb))
1487 			goto __error;
1488 
1489 		if (is_playback)
1490 			err = prepare_outbound_urb(ep, urb->context, true);
1491 		else
1492 			err = prepare_inbound_urb(ep, urb->context);
1493 		if (err < 0) {
1494 			/* stop filling at applptr */
1495 			if (err == -EAGAIN)
1496 				break;
1497 			usb_audio_dbg(ep->chip,
1498 				      "EP 0x%x: failed to prepare urb: %d\n",
1499 				      ep->ep_num, err);
1500 			goto __error;
1501 		}
1502 
1503 		err = usb_submit_urb(urb, GFP_ATOMIC);
1504 		if (err < 0) {
1505 			usb_audio_err(ep->chip,
1506 				"cannot submit urb %d, error %d: %s\n",
1507 				i, err, usb_error_string(err));
1508 			goto __error;
1509 		}
1510 		set_bit(i, &ep->active_mask);
1511 		atomic_inc(&ep->submitted_urbs);
1512 	}
1513 
1514 	if (!i) {
1515 		usb_audio_dbg(ep->chip, "XRUN at starting EP 0x%x\n",
1516 			      ep->ep_num);
1517 		goto __error;
1518 	}
1519 
1520 	usb_audio_dbg(ep->chip, "%d URBs submitted for EP 0x%x\n",
1521 		      i, ep->ep_num);
1522 
1523  fill_rest:
1524 	/* put the remaining URBs to ready list */
1525 	if (is_playback) {
1526 		for (; i < ep->nurbs; i++)
1527 			push_back_to_ready_list(ep, ep->urb + i);
1528 	}
1529 
1530 	return 0;
1531 
1532 __error:
1533 	snd_usb_endpoint_stop(ep, false);
1534 	return -EPIPE;
1535 }
1536 
1537 /**
1538  * snd_usb_endpoint_stop: stop an snd_usb_endpoint
1539  *
1540  * @ep: the endpoint to stop (may be NULL)
1541  * @keep_pending: keep in-flight URBs
1542  *
1543  * A call to this function will decrement the running count of the endpoint.
1544  * In case the last user has requested the endpoint stop, the URBs will
1545  * actually be deactivated.
1546  *
1547  * Must be balanced to calls of snd_usb_endpoint_start().
1548  *
1549  * The caller needs to synchronize the pending stop operation via
1550  * snd_usb_endpoint_sync_pending_stop().
1551  */
1552 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending)
1553 {
1554 	if (!ep)
1555 		return;
1556 
1557 	usb_audio_dbg(ep->chip, "Stopping %s EP 0x%x (running %d)\n",
1558 		      ep_type_name(ep->type), ep->ep_num,
1559 		      atomic_read(&ep->running));
1560 
1561 	if (snd_BUG_ON(!atomic_read(&ep->running)))
1562 		return;
1563 
1564 	if (!atomic_dec_return(&ep->running)) {
1565 		if (ep->sync_source)
1566 			WRITE_ONCE(ep->sync_source->sync_sink, NULL);
1567 		stop_urbs(ep, false, keep_pending);
1568 	}
1569 }
1570 
1571 /**
1572  * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1573  *
1574  * @ep: the endpoint to release
1575  *
1576  * This function does not care for the endpoint's running count but will tear
1577  * down all the streaming URBs immediately.
1578  */
1579 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1580 {
1581 	release_urbs(ep, true);
1582 }
1583 
1584 /**
1585  * snd_usb_endpoint_free_all: Free the resources of an snd_usb_endpoint
1586  * @chip: The chip
1587  *
1588  * This free all endpoints and those resources
1589  */
1590 void snd_usb_endpoint_free_all(struct snd_usb_audio *chip)
1591 {
1592 	struct snd_usb_endpoint *ep, *en;
1593 	struct snd_usb_iface_ref *ip, *in;
1594 
1595 	list_for_each_entry_safe(ep, en, &chip->ep_list, list)
1596 		kfree(ep);
1597 
1598 	list_for_each_entry_safe(ip, in, &chip->iface_ref_list, list)
1599 		kfree(ip);
1600 }
1601 
1602 /*
1603  * snd_usb_handle_sync_urb: parse an USB sync packet
1604  *
1605  * @ep: the endpoint to handle the packet
1606  * @sender: the sending endpoint
1607  * @urb: the received packet
1608  *
1609  * This function is called from the context of an endpoint that received
1610  * the packet and is used to let another endpoint object handle the payload.
1611  */
1612 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1613 				    struct snd_usb_endpoint *sender,
1614 				    const struct urb *urb)
1615 {
1616 	int shift;
1617 	unsigned int f;
1618 	unsigned long flags;
1619 
1620 	snd_BUG_ON(ep == sender);
1621 
1622 	/*
1623 	 * In case the endpoint is operating in implicit feedback mode, prepare
1624 	 * a new outbound URB that has the same layout as the received packet
1625 	 * and add it to the list of pending urbs. queue_pending_output_urbs()
1626 	 * will take care of them later.
1627 	 */
1628 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1629 	    atomic_read(&ep->running)) {
1630 
1631 		/* implicit feedback case */
1632 		int i, bytes = 0;
1633 		struct snd_urb_ctx *in_ctx;
1634 		struct snd_usb_packet_info *out_packet;
1635 
1636 		in_ctx = urb->context;
1637 
1638 		/* Count overall packet size */
1639 		for (i = 0; i < in_ctx->packets; i++)
1640 			if (urb->iso_frame_desc[i].status == 0)
1641 				bytes += urb->iso_frame_desc[i].actual_length;
1642 
1643 		/*
1644 		 * skip empty packets. At least M-Audio's Fast Track Ultra stops
1645 		 * streaming once it received a 0-byte OUT URB
1646 		 */
1647 		if (bytes == 0)
1648 			return;
1649 
1650 		spin_lock_irqsave(&ep->lock, flags);
1651 		if (ep->next_packet_queued >= ARRAY_SIZE(ep->next_packet)) {
1652 			spin_unlock_irqrestore(&ep->lock, flags);
1653 			usb_audio_err(ep->chip,
1654 				      "next package FIFO overflow EP 0x%x\n",
1655 				      ep->ep_num);
1656 			notify_xrun(ep);
1657 			return;
1658 		}
1659 
1660 		out_packet = next_packet_fifo_enqueue(ep);
1661 
1662 		/*
1663 		 * Iterate through the inbound packet and prepare the lengths
1664 		 * for the output packet. The OUT packet we are about to send
1665 		 * will have the same amount of payload bytes per stride as the
1666 		 * IN packet we just received. Since the actual size is scaled
1667 		 * by the stride, use the sender stride to calculate the length
1668 		 * in case the number of channels differ between the implicitly
1669 		 * fed-back endpoint and the synchronizing endpoint.
1670 		 */
1671 
1672 		out_packet->packets = in_ctx->packets;
1673 		for (i = 0; i < in_ctx->packets; i++) {
1674 			if (urb->iso_frame_desc[i].status == 0)
1675 				out_packet->packet_size[i] =
1676 					urb->iso_frame_desc[i].actual_length / sender->stride;
1677 			else
1678 				out_packet->packet_size[i] = 0;
1679 		}
1680 
1681 		spin_unlock_irqrestore(&ep->lock, flags);
1682 		snd_usb_queue_pending_output_urbs(ep, false);
1683 
1684 		return;
1685 	}
1686 
1687 	/*
1688 	 * process after playback sync complete
1689 	 *
1690 	 * Full speed devices report feedback values in 10.14 format as samples
1691 	 * per frame, high speed devices in 16.16 format as samples per
1692 	 * microframe.
1693 	 *
1694 	 * Because the Audio Class 1 spec was written before USB 2.0, many high
1695 	 * speed devices use a wrong interpretation, some others use an
1696 	 * entirely different format.
1697 	 *
1698 	 * Therefore, we cannot predict what format any particular device uses
1699 	 * and must detect it automatically.
1700 	 */
1701 
1702 	if (urb->iso_frame_desc[0].status != 0 ||
1703 	    urb->iso_frame_desc[0].actual_length < 3)
1704 		return;
1705 
1706 	f = le32_to_cpup(urb->transfer_buffer);
1707 	if (urb->iso_frame_desc[0].actual_length == 3)
1708 		f &= 0x00ffffff;
1709 	else
1710 		f &= 0x0fffffff;
1711 
1712 	if (f == 0)
1713 		return;
1714 
1715 	if (unlikely(sender->tenor_fb_quirk)) {
1716 		/*
1717 		 * Devices based on Tenor 8802 chipsets (TEAC UD-H01
1718 		 * and others) sometimes change the feedback value
1719 		 * by +/- 0x1.0000.
1720 		 */
1721 		if (f < ep->freqn - 0x8000)
1722 			f += 0xf000;
1723 		else if (f > ep->freqn + 0x8000)
1724 			f -= 0xf000;
1725 	} else if (unlikely(ep->freqshift == INT_MIN)) {
1726 		/*
1727 		 * The first time we see a feedback value, determine its format
1728 		 * by shifting it left or right until it matches the nominal
1729 		 * frequency value.  This assumes that the feedback does not
1730 		 * differ from the nominal value more than +50% or -25%.
1731 		 */
1732 		shift = 0;
1733 		while (f < ep->freqn - ep->freqn / 4) {
1734 			f <<= 1;
1735 			shift++;
1736 		}
1737 		while (f > ep->freqn + ep->freqn / 2) {
1738 			f >>= 1;
1739 			shift--;
1740 		}
1741 		ep->freqshift = shift;
1742 	} else if (ep->freqshift >= 0)
1743 		f <<= ep->freqshift;
1744 	else
1745 		f >>= -ep->freqshift;
1746 
1747 	if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1748 		/*
1749 		 * If the frequency looks valid, set it.
1750 		 * This value is referred to in prepare_playback_urb().
1751 		 */
1752 		spin_lock_irqsave(&ep->lock, flags);
1753 		ep->freqm = f;
1754 		spin_unlock_irqrestore(&ep->lock, flags);
1755 	} else {
1756 		/*
1757 		 * Out of range; maybe the shift value is wrong.
1758 		 * Reset it so that we autodetect again the next time.
1759 		 */
1760 		ep->freqshift = INT_MIN;
1761 	}
1762 }
1763 
1764