xref: /openbmc/linux/sound/usb/endpoint.c (revision 2f7ab126)
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_try_cmpxchg(&ep->state, &old, new);
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 		if (ep->clock_ref && !atomic_read(&ep->clock_ref->locked))
928 			ep->clock_ref->rate = 0;
929 		ep->iface = 0;
930 		ep->altsetting = 0;
931 		ep->cur_audiofmt = NULL;
932 		ep->cur_rate = 0;
933 		ep->iface_ref = NULL;
934 		ep->clock_ref = NULL;
935 		usb_audio_dbg(chip, "EP 0x%x closed\n", ep->ep_num);
936 	}
937 	mutex_unlock(&chip->mutex);
938 }
939 
940 /* Prepare for suspening EP, called from the main suspend handler */
941 void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep)
942 {
943 	ep->need_setup = true;
944 	if (ep->iface_ref)
945 		ep->iface_ref->need_setup = true;
946 	if (ep->clock_ref)
947 		ep->clock_ref->rate = 0;
948 }
949 
950 /*
951  *  wait until all urbs are processed.
952  */
953 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
954 {
955 	unsigned long end_time = jiffies + msecs_to_jiffies(1000);
956 	int alive;
957 
958 	if (atomic_read(&ep->state) != EP_STATE_STOPPING)
959 		return 0;
960 
961 	do {
962 		alive = atomic_read(&ep->submitted_urbs);
963 		if (!alive)
964 			break;
965 
966 		schedule_timeout_uninterruptible(1);
967 	} while (time_before(jiffies, end_time));
968 
969 	if (alive)
970 		usb_audio_err(ep->chip,
971 			"timeout: still %d active urbs on EP #%x\n",
972 			alive, ep->ep_num);
973 
974 	if (ep_state_update(ep, EP_STATE_STOPPING, EP_STATE_STOPPED)) {
975 		ep->sync_sink = NULL;
976 		snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
977 	}
978 
979 	return 0;
980 }
981 
982 /* sync the pending stop operation;
983  * this function itself doesn't trigger the stop operation
984  */
985 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
986 {
987 	if (ep)
988 		wait_clear_urbs(ep);
989 }
990 
991 /*
992  * Stop active urbs
993  *
994  * This function moves the EP to STOPPING state if it's being RUNNING.
995  */
996 static int stop_urbs(struct snd_usb_endpoint *ep, bool force, bool keep_pending)
997 {
998 	unsigned int i;
999 	unsigned long flags;
1000 
1001 	if (!force && atomic_read(&ep->running))
1002 		return -EBUSY;
1003 
1004 	if (!ep_state_update(ep, EP_STATE_RUNNING, EP_STATE_STOPPING))
1005 		return 0;
1006 
1007 	spin_lock_irqsave(&ep->lock, flags);
1008 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
1009 	ep->next_packet_head = 0;
1010 	ep->next_packet_queued = 0;
1011 	spin_unlock_irqrestore(&ep->lock, flags);
1012 
1013 	if (keep_pending)
1014 		return 0;
1015 
1016 	for (i = 0; i < ep->nurbs; i++) {
1017 		if (test_bit(i, &ep->active_mask)) {
1018 			if (!test_and_set_bit(i, &ep->unlink_mask)) {
1019 				struct urb *u = ep->urb[i].urb;
1020 				usb_unlink_urb(u);
1021 			}
1022 		}
1023 	}
1024 
1025 	return 0;
1026 }
1027 
1028 /*
1029  * release an endpoint's urbs
1030  */
1031 static int release_urbs(struct snd_usb_endpoint *ep, bool force)
1032 {
1033 	int i, err;
1034 
1035 	/* route incoming urbs to nirvana */
1036 	snd_usb_endpoint_set_callback(ep, NULL, NULL, NULL);
1037 
1038 	/* stop and unlink urbs */
1039 	err = stop_urbs(ep, force, false);
1040 	if (err)
1041 		return err;
1042 
1043 	wait_clear_urbs(ep);
1044 
1045 	for (i = 0; i < ep->nurbs; i++)
1046 		release_urb_ctx(&ep->urb[i]);
1047 
1048 	usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
1049 			  ep->syncbuf, ep->sync_dma);
1050 
1051 	ep->syncbuf = NULL;
1052 	ep->nurbs = 0;
1053 	return 0;
1054 }
1055 
1056 /*
1057  * configure a data endpoint
1058  */
1059 static int data_ep_set_params(struct snd_usb_endpoint *ep)
1060 {
1061 	struct snd_usb_audio *chip = ep->chip;
1062 	unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
1063 	unsigned int max_packs_per_period, urbs_per_period, urb_packs;
1064 	unsigned int max_urbs, i;
1065 	const struct audioformat *fmt = ep->cur_audiofmt;
1066 	int frame_bits = ep->cur_frame_bytes * 8;
1067 	int tx_length_quirk = (has_tx_length_quirk(chip) &&
1068 			       usb_pipeout(ep->pipe));
1069 
1070 	usb_audio_dbg(chip, "Setting params for data EP 0x%x, pipe 0x%x\n",
1071 		      ep->ep_num, ep->pipe);
1072 
1073 	if (ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
1074 		/*
1075 		 * When operating in DSD DOP mode, the size of a sample frame
1076 		 * in hardware differs from the actual physical format width
1077 		 * because we need to make room for the DOP markers.
1078 		 */
1079 		frame_bits += ep->cur_channels << 3;
1080 	}
1081 
1082 	ep->datainterval = fmt->datainterval;
1083 	ep->stride = frame_bits >> 3;
1084 
1085 	switch (ep->cur_format) {
1086 	case SNDRV_PCM_FORMAT_U8:
1087 		ep->silence_value = 0x80;
1088 		break;
1089 	case SNDRV_PCM_FORMAT_DSD_U8:
1090 	case SNDRV_PCM_FORMAT_DSD_U16_LE:
1091 	case SNDRV_PCM_FORMAT_DSD_U32_LE:
1092 	case SNDRV_PCM_FORMAT_DSD_U16_BE:
1093 	case SNDRV_PCM_FORMAT_DSD_U32_BE:
1094 		ep->silence_value = 0x69;
1095 		break;
1096 	default:
1097 		ep->silence_value = 0;
1098 	}
1099 
1100 	/* assume max. frequency is 50% higher than nominal */
1101 	ep->freqmax = ep->freqn + (ep->freqn >> 1);
1102 	/* Round up freqmax to nearest integer in order to calculate maximum
1103 	 * packet size, which must represent a whole number of frames.
1104 	 * This is accomplished by adding 0x0.ffff before converting the
1105 	 * Q16.16 format into integer.
1106 	 * In order to accurately calculate the maximum packet size when
1107 	 * the data interval is more than 1 (i.e. ep->datainterval > 0),
1108 	 * multiply by the data interval prior to rounding. For instance,
1109 	 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
1110 	 * frames with a data interval of 1, but 11 (10.25) frames with a
1111 	 * data interval of 2.
1112 	 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
1113 	 * maximum datainterval value of 3, at USB full speed, higher for
1114 	 * USB high speed, noting that ep->freqmax is in units of
1115 	 * frames per packet in Q16.16 format.)
1116 	 */
1117 	maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
1118 			 (frame_bits >> 3);
1119 	if (tx_length_quirk)
1120 		maxsize += sizeof(__le32); /* Space for length descriptor */
1121 	/* but wMaxPacketSize might reduce this */
1122 	if (ep->maxpacksize && ep->maxpacksize < maxsize) {
1123 		/* whatever fits into a max. size packet */
1124 		unsigned int data_maxsize = maxsize = ep->maxpacksize;
1125 
1126 		if (tx_length_quirk)
1127 			/* Need to remove the length descriptor to calc freq */
1128 			data_maxsize -= sizeof(__le32);
1129 		ep->freqmax = (data_maxsize / (frame_bits >> 3))
1130 				<< (16 - ep->datainterval);
1131 	}
1132 
1133 	if (ep->fill_max)
1134 		ep->curpacksize = ep->maxpacksize;
1135 	else
1136 		ep->curpacksize = maxsize;
1137 
1138 	if (snd_usb_get_speed(chip->dev) != USB_SPEED_FULL) {
1139 		packs_per_ms = 8 >> ep->datainterval;
1140 		max_packs_per_urb = MAX_PACKS_HS;
1141 	} else {
1142 		packs_per_ms = 1;
1143 		max_packs_per_urb = MAX_PACKS;
1144 	}
1145 	if (ep->sync_source && !ep->implicit_fb_sync)
1146 		max_packs_per_urb = min(max_packs_per_urb,
1147 					1U << ep->sync_source->syncinterval);
1148 	max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
1149 
1150 	/*
1151 	 * Capture endpoints need to use small URBs because there's no way
1152 	 * to tell in advance where the next period will end, and we don't
1153 	 * want the next URB to complete much after the period ends.
1154 	 *
1155 	 * Playback endpoints with implicit sync much use the same parameters
1156 	 * as their corresponding capture endpoint.
1157 	 */
1158 	if (usb_pipein(ep->pipe) || ep->implicit_fb_sync) {
1159 
1160 		urb_packs = packs_per_ms;
1161 		/*
1162 		 * Wireless devices can poll at a max rate of once per 4ms.
1163 		 * For dataintervals less than 5, increase the packet count to
1164 		 * allow the host controller to use bursting to fill in the
1165 		 * gaps.
1166 		 */
1167 		if (snd_usb_get_speed(chip->dev) == USB_SPEED_WIRELESS) {
1168 			int interval = ep->datainterval;
1169 			while (interval < 5) {
1170 				urb_packs <<= 1;
1171 				++interval;
1172 			}
1173 		}
1174 		/* make capture URBs <= 1 ms and smaller than a period */
1175 		urb_packs = min(max_packs_per_urb, urb_packs);
1176 		while (urb_packs > 1 && urb_packs * maxsize >= ep->cur_period_bytes)
1177 			urb_packs >>= 1;
1178 		ep->nurbs = MAX_URBS;
1179 
1180 	/*
1181 	 * Playback endpoints without implicit sync are adjusted so that
1182 	 * a period fits as evenly as possible in the smallest number of
1183 	 * URBs.  The total number of URBs is adjusted to the size of the
1184 	 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
1185 	 */
1186 	} else {
1187 		/* determine how small a packet can be */
1188 		minsize = (ep->freqn >> (16 - ep->datainterval)) *
1189 				(frame_bits >> 3);
1190 		/* with sync from device, assume it can be 12% lower */
1191 		if (ep->sync_source)
1192 			minsize -= minsize >> 3;
1193 		minsize = max(minsize, 1u);
1194 
1195 		/* how many packets will contain an entire ALSA period? */
1196 		max_packs_per_period = DIV_ROUND_UP(ep->cur_period_bytes, minsize);
1197 
1198 		/* how many URBs will contain a period? */
1199 		urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
1200 				max_packs_per_urb);
1201 		/* how many packets are needed in each URB? */
1202 		urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
1203 
1204 		/* limit the number of frames in a single URB */
1205 		ep->max_urb_frames = DIV_ROUND_UP(ep->cur_period_frames,
1206 						  urbs_per_period);
1207 
1208 		/* try to use enough URBs to contain an entire ALSA buffer */
1209 		max_urbs = min((unsigned) MAX_URBS,
1210 				MAX_QUEUE * packs_per_ms / urb_packs);
1211 		ep->nurbs = min(max_urbs, urbs_per_period * ep->cur_buffer_periods);
1212 	}
1213 
1214 	/* allocate and initialize data urbs */
1215 	for (i = 0; i < ep->nurbs; i++) {
1216 		struct snd_urb_ctx *u = &ep->urb[i];
1217 		u->index = i;
1218 		u->ep = ep;
1219 		u->packets = urb_packs;
1220 		u->buffer_size = maxsize * u->packets;
1221 
1222 		if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
1223 			u->packets++; /* for transfer delimiter */
1224 		u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
1225 		if (!u->urb)
1226 			goto out_of_memory;
1227 
1228 		u->urb->transfer_buffer =
1229 			usb_alloc_coherent(chip->dev, u->buffer_size,
1230 					   GFP_KERNEL, &u->urb->transfer_dma);
1231 		if (!u->urb->transfer_buffer)
1232 			goto out_of_memory;
1233 		u->urb->pipe = ep->pipe;
1234 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1235 		u->urb->interval = 1 << ep->datainterval;
1236 		u->urb->context = u;
1237 		u->urb->complete = snd_complete_urb;
1238 		INIT_LIST_HEAD(&u->ready_list);
1239 	}
1240 
1241 	return 0;
1242 
1243 out_of_memory:
1244 	release_urbs(ep, false);
1245 	return -ENOMEM;
1246 }
1247 
1248 /*
1249  * configure a sync endpoint
1250  */
1251 static int sync_ep_set_params(struct snd_usb_endpoint *ep)
1252 {
1253 	struct snd_usb_audio *chip = ep->chip;
1254 	int i;
1255 
1256 	usb_audio_dbg(chip, "Setting params for sync EP 0x%x, pipe 0x%x\n",
1257 		      ep->ep_num, ep->pipe);
1258 
1259 	ep->syncbuf = usb_alloc_coherent(chip->dev, SYNC_URBS * 4,
1260 					 GFP_KERNEL, &ep->sync_dma);
1261 	if (!ep->syncbuf)
1262 		return -ENOMEM;
1263 
1264 	for (i = 0; i < SYNC_URBS; i++) {
1265 		struct snd_urb_ctx *u = &ep->urb[i];
1266 		u->index = i;
1267 		u->ep = ep;
1268 		u->packets = 1;
1269 		u->urb = usb_alloc_urb(1, GFP_KERNEL);
1270 		if (!u->urb)
1271 			goto out_of_memory;
1272 		u->urb->transfer_buffer = ep->syncbuf + i * 4;
1273 		u->urb->transfer_dma = ep->sync_dma + i * 4;
1274 		u->urb->transfer_buffer_length = 4;
1275 		u->urb->pipe = ep->pipe;
1276 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
1277 		u->urb->number_of_packets = 1;
1278 		u->urb->interval = 1 << ep->syncinterval;
1279 		u->urb->context = u;
1280 		u->urb->complete = snd_complete_urb;
1281 	}
1282 
1283 	ep->nurbs = SYNC_URBS;
1284 
1285 	return 0;
1286 
1287 out_of_memory:
1288 	release_urbs(ep, false);
1289 	return -ENOMEM;
1290 }
1291 
1292 /*
1293  * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
1294  *
1295  * Determine the number of URBs to be used on this endpoint.
1296  * An endpoint must be configured before it can be started.
1297  * An endpoint that is already running can not be reconfigured.
1298  */
1299 static int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
1300 				       struct snd_usb_endpoint *ep)
1301 {
1302 	const struct audioformat *fmt = ep->cur_audiofmt;
1303 	int err;
1304 
1305 	/* release old buffers, if any */
1306 	err = release_urbs(ep, false);
1307 	if (err < 0)
1308 		return err;
1309 
1310 	ep->datainterval = fmt->datainterval;
1311 	ep->maxpacksize = fmt->maxpacksize;
1312 	ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
1313 
1314 	if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL) {
1315 		ep->freqn = get_usb_full_speed_rate(ep->cur_rate);
1316 		ep->pps = 1000 >> ep->datainterval;
1317 	} else {
1318 		ep->freqn = get_usb_high_speed_rate(ep->cur_rate);
1319 		ep->pps = 8000 >> ep->datainterval;
1320 	}
1321 
1322 	ep->sample_rem = ep->cur_rate % ep->pps;
1323 	ep->packsize[0] = ep->cur_rate / ep->pps;
1324 	ep->packsize[1] = (ep->cur_rate + (ep->pps - 1)) / ep->pps;
1325 
1326 	/* calculate the frequency in 16.16 format */
1327 	ep->freqm = ep->freqn;
1328 	ep->freqshift = INT_MIN;
1329 
1330 	ep->phase = 0;
1331 
1332 	switch (ep->type) {
1333 	case  SND_USB_ENDPOINT_TYPE_DATA:
1334 		err = data_ep_set_params(ep);
1335 		break;
1336 	case  SND_USB_ENDPOINT_TYPE_SYNC:
1337 		err = sync_ep_set_params(ep);
1338 		break;
1339 	default:
1340 		err = -EINVAL;
1341 	}
1342 
1343 	usb_audio_dbg(chip, "Set up %d URBS, ret=%d\n", ep->nurbs, err);
1344 
1345 	if (err < 0)
1346 		return err;
1347 
1348 	/* some unit conversions in runtime */
1349 	ep->maxframesize = ep->maxpacksize / ep->cur_frame_bytes;
1350 	ep->curframesize = ep->curpacksize / ep->cur_frame_bytes;
1351 
1352 	return 0;
1353 }
1354 
1355 static int init_sample_rate(struct snd_usb_audio *chip,
1356 			    struct snd_usb_endpoint *ep)
1357 {
1358 	struct snd_usb_clock_ref *clock = ep->clock_ref;
1359 	int err;
1360 
1361 	if (clock) {
1362 		if (atomic_read(&clock->locked))
1363 			return 0;
1364 		if (clock->rate == ep->cur_rate)
1365 			return 0;
1366 		if (clock->rate && clock->rate != ep->cur_rate) {
1367 			usb_audio_dbg(chip, "Mismatched sample rate %d vs %d for EP 0x%x\n",
1368 				      clock->rate, ep->cur_rate, ep->ep_num);
1369 			return -EINVAL;
1370 		}
1371 	}
1372 
1373 	err = snd_usb_init_sample_rate(chip, ep->cur_audiofmt, ep->cur_rate);
1374 	if (err < 0)
1375 		return err;
1376 
1377 	if (clock)
1378 		clock->rate = ep->cur_rate;
1379 	return 0;
1380 }
1381 
1382 /*
1383  * snd_usb_endpoint_configure: Configure the endpoint
1384  *
1385  * This function sets up the EP to be fully usable state.
1386  * It's called either from hw_params or prepare callback.
1387  * The function checks need_setup flag, and performs nothing unless needed,
1388  * so it's safe to call this multiple times.
1389  *
1390  * This returns zero if unchanged, 1 if the configuration has changed,
1391  * or a negative error code.
1392  */
1393 int snd_usb_endpoint_configure(struct snd_usb_audio *chip,
1394 			       struct snd_usb_endpoint *ep)
1395 {
1396 	bool iface_first;
1397 	int err = 0;
1398 
1399 	mutex_lock(&chip->mutex);
1400 	if (WARN_ON(!ep->iface_ref))
1401 		goto unlock;
1402 	if (!ep->need_setup)
1403 		goto unlock;
1404 
1405 	/* If the interface has been already set up, just set EP parameters */
1406 	if (!ep->iface_ref->need_setup) {
1407 		/* sample rate setup of UAC1 is per endpoint, and we need
1408 		 * to update at each EP configuration
1409 		 */
1410 		if (ep->cur_audiofmt->protocol == UAC_VERSION_1) {
1411 			err = init_sample_rate(chip, ep);
1412 			if (err < 0)
1413 				goto unlock;
1414 		}
1415 		err = snd_usb_endpoint_set_params(chip, ep);
1416 		if (err < 0)
1417 			goto unlock;
1418 		goto done;
1419 	}
1420 
1421 	/* Need to deselect altsetting at first */
1422 	endpoint_set_interface(chip, ep, false);
1423 
1424 	/* Some UAC1 devices (e.g. Yamaha THR10) need the host interface
1425 	 * to be set up before parameter setups
1426 	 */
1427 	iface_first = ep->cur_audiofmt->protocol == UAC_VERSION_1;
1428 	/* Workaround for devices that require the interface setup at first like UAC1 */
1429 	if (chip->quirk_flags & QUIRK_FLAG_SET_IFACE_FIRST)
1430 		iface_first = true;
1431 	if (iface_first) {
1432 		err = endpoint_set_interface(chip, ep, true);
1433 		if (err < 0)
1434 			goto unlock;
1435 	}
1436 
1437 	err = snd_usb_init_pitch(chip, ep->cur_audiofmt);
1438 	if (err < 0)
1439 		goto unlock;
1440 
1441 	err = init_sample_rate(chip, ep);
1442 	if (err < 0)
1443 		goto unlock;
1444 
1445 	err = snd_usb_endpoint_set_params(chip, ep);
1446 	if (err < 0)
1447 		goto unlock;
1448 
1449 	err = snd_usb_select_mode_quirk(chip, ep->cur_audiofmt);
1450 	if (err < 0)
1451 		goto unlock;
1452 
1453 	/* for UAC2/3, enable the interface altset here at last */
1454 	if (!iface_first) {
1455 		err = endpoint_set_interface(chip, ep, true);
1456 		if (err < 0)
1457 			goto unlock;
1458 	}
1459 
1460 	ep->iface_ref->need_setup = false;
1461 
1462  done:
1463 	ep->need_setup = false;
1464 	err = 1;
1465 
1466 unlock:
1467 	mutex_unlock(&chip->mutex);
1468 	return err;
1469 }
1470 
1471 /* get the current rate set to the given clock by any endpoint */
1472 int snd_usb_endpoint_get_clock_rate(struct snd_usb_audio *chip, int clock)
1473 {
1474 	struct snd_usb_clock_ref *ref;
1475 	int rate = 0;
1476 
1477 	if (!clock)
1478 		return 0;
1479 	mutex_lock(&chip->mutex);
1480 	list_for_each_entry(ref, &chip->clock_ref_list, list) {
1481 		if (ref->clock == clock) {
1482 			rate = ref->rate;
1483 			break;
1484 		}
1485 	}
1486 	mutex_unlock(&chip->mutex);
1487 	return rate;
1488 }
1489 
1490 /**
1491  * snd_usb_endpoint_start: start an snd_usb_endpoint
1492  *
1493  * @ep: the endpoint to start
1494  *
1495  * A call to this function will increment the running count of the endpoint.
1496  * In case it is not already running, the URBs for this endpoint will be
1497  * submitted. Otherwise, this function does nothing.
1498  *
1499  * Must be balanced to calls of snd_usb_endpoint_stop().
1500  *
1501  * Returns an error if the URB submission failed, 0 in all other cases.
1502  */
1503 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
1504 {
1505 	bool is_playback = usb_pipeout(ep->pipe);
1506 	int err;
1507 	unsigned int i;
1508 
1509 	if (atomic_read(&ep->chip->shutdown))
1510 		return -EBADFD;
1511 
1512 	if (ep->sync_source)
1513 		WRITE_ONCE(ep->sync_source->sync_sink, ep);
1514 
1515 	usb_audio_dbg(ep->chip, "Starting %s EP 0x%x (running %d)\n",
1516 		      ep_type_name(ep->type), ep->ep_num,
1517 		      atomic_read(&ep->running));
1518 
1519 	/* already running? */
1520 	if (atomic_inc_return(&ep->running) != 1)
1521 		return 0;
1522 
1523 	if (ep->clock_ref)
1524 		atomic_inc(&ep->clock_ref->locked);
1525 
1526 	ep->active_mask = 0;
1527 	ep->unlink_mask = 0;
1528 	ep->phase = 0;
1529 	ep->sample_accum = 0;
1530 
1531 	snd_usb_endpoint_start_quirk(ep);
1532 
1533 	/*
1534 	 * If this endpoint has a data endpoint as implicit feedback source,
1535 	 * don't start the urbs here. Instead, mark them all as available,
1536 	 * wait for the record urbs to return and queue the playback urbs
1537 	 * from that context.
1538 	 */
1539 
1540 	if (!ep_state_update(ep, EP_STATE_STOPPED, EP_STATE_RUNNING))
1541 		goto __error;
1542 
1543 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1544 	    !(ep->chip->quirk_flags & QUIRK_FLAG_PLAYBACK_FIRST)) {
1545 		usb_audio_dbg(ep->chip, "No URB submission due to implicit fb sync\n");
1546 		i = 0;
1547 		goto fill_rest;
1548 	}
1549 
1550 	for (i = 0; i < ep->nurbs; i++) {
1551 		struct urb *urb = ep->urb[i].urb;
1552 
1553 		if (snd_BUG_ON(!urb))
1554 			goto __error;
1555 
1556 		if (is_playback)
1557 			err = prepare_outbound_urb(ep, urb->context, true);
1558 		else
1559 			err = prepare_inbound_urb(ep, urb->context);
1560 		if (err < 0) {
1561 			/* stop filling at applptr */
1562 			if (err == -EAGAIN)
1563 				break;
1564 			usb_audio_dbg(ep->chip,
1565 				      "EP 0x%x: failed to prepare urb: %d\n",
1566 				      ep->ep_num, err);
1567 			goto __error;
1568 		}
1569 
1570 		err = usb_submit_urb(urb, GFP_ATOMIC);
1571 		if (err < 0) {
1572 			usb_audio_err(ep->chip,
1573 				"cannot submit urb %d, error %d: %s\n",
1574 				i, err, usb_error_string(err));
1575 			goto __error;
1576 		}
1577 		set_bit(i, &ep->active_mask);
1578 		atomic_inc(&ep->submitted_urbs);
1579 	}
1580 
1581 	if (!i) {
1582 		usb_audio_dbg(ep->chip, "XRUN at starting EP 0x%x\n",
1583 			      ep->ep_num);
1584 		goto __error;
1585 	}
1586 
1587 	usb_audio_dbg(ep->chip, "%d URBs submitted for EP 0x%x\n",
1588 		      i, ep->ep_num);
1589 
1590  fill_rest:
1591 	/* put the remaining URBs to ready list */
1592 	if (is_playback) {
1593 		for (; i < ep->nurbs; i++)
1594 			push_back_to_ready_list(ep, ep->urb + i);
1595 	}
1596 
1597 	return 0;
1598 
1599 __error:
1600 	snd_usb_endpoint_stop(ep, false);
1601 	return -EPIPE;
1602 }
1603 
1604 /**
1605  * snd_usb_endpoint_stop: stop an snd_usb_endpoint
1606  *
1607  * @ep: the endpoint to stop (may be NULL)
1608  * @keep_pending: keep in-flight URBs
1609  *
1610  * A call to this function will decrement the running count of the endpoint.
1611  * In case the last user has requested the endpoint stop, the URBs will
1612  * actually be deactivated.
1613  *
1614  * Must be balanced to calls of snd_usb_endpoint_start().
1615  *
1616  * The caller needs to synchronize the pending stop operation via
1617  * snd_usb_endpoint_sync_pending_stop().
1618  */
1619 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep, bool keep_pending)
1620 {
1621 	if (!ep)
1622 		return;
1623 
1624 	usb_audio_dbg(ep->chip, "Stopping %s EP 0x%x (running %d)\n",
1625 		      ep_type_name(ep->type), ep->ep_num,
1626 		      atomic_read(&ep->running));
1627 
1628 	if (snd_BUG_ON(!atomic_read(&ep->running)))
1629 		return;
1630 
1631 	if (!atomic_dec_return(&ep->running)) {
1632 		if (ep->sync_source)
1633 			WRITE_ONCE(ep->sync_source->sync_sink, NULL);
1634 		stop_urbs(ep, false, keep_pending);
1635 		if (ep->clock_ref)
1636 			if (!atomic_dec_return(&ep->clock_ref->locked))
1637 				ep->clock_ref->rate = 0;
1638 	}
1639 }
1640 
1641 /**
1642  * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1643  *
1644  * @ep: the endpoint to release
1645  *
1646  * This function does not care for the endpoint's running count but will tear
1647  * down all the streaming URBs immediately.
1648  */
1649 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1650 {
1651 	release_urbs(ep, true);
1652 }
1653 
1654 /**
1655  * snd_usb_endpoint_free_all: Free the resources of an snd_usb_endpoint
1656  * @chip: The chip
1657  *
1658  * This free all endpoints and those resources
1659  */
1660 void snd_usb_endpoint_free_all(struct snd_usb_audio *chip)
1661 {
1662 	struct snd_usb_endpoint *ep, *en;
1663 	struct snd_usb_iface_ref *ip, *in;
1664 	struct snd_usb_clock_ref *cp, *cn;
1665 
1666 	list_for_each_entry_safe(ep, en, &chip->ep_list, list)
1667 		kfree(ep);
1668 
1669 	list_for_each_entry_safe(ip, in, &chip->iface_ref_list, list)
1670 		kfree(ip);
1671 
1672 	list_for_each_entry_safe(cp, cn, &chip->clock_ref_list, list)
1673 		kfree(cp);
1674 }
1675 
1676 /*
1677  * snd_usb_handle_sync_urb: parse an USB sync packet
1678  *
1679  * @ep: the endpoint to handle the packet
1680  * @sender: the sending endpoint
1681  * @urb: the received packet
1682  *
1683  * This function is called from the context of an endpoint that received
1684  * the packet and is used to let another endpoint object handle the payload.
1685  */
1686 static void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1687 				    struct snd_usb_endpoint *sender,
1688 				    const struct urb *urb)
1689 {
1690 	int shift;
1691 	unsigned int f;
1692 	unsigned long flags;
1693 
1694 	snd_BUG_ON(ep == sender);
1695 
1696 	/*
1697 	 * In case the endpoint is operating in implicit feedback mode, prepare
1698 	 * a new outbound URB that has the same layout as the received packet
1699 	 * and add it to the list of pending urbs. queue_pending_output_urbs()
1700 	 * will take care of them later.
1701 	 */
1702 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1703 	    atomic_read(&ep->running)) {
1704 
1705 		/* implicit feedback case */
1706 		int i, bytes = 0;
1707 		struct snd_urb_ctx *in_ctx;
1708 		struct snd_usb_packet_info *out_packet;
1709 
1710 		in_ctx = urb->context;
1711 
1712 		/* Count overall packet size */
1713 		for (i = 0; i < in_ctx->packets; i++)
1714 			if (urb->iso_frame_desc[i].status == 0)
1715 				bytes += urb->iso_frame_desc[i].actual_length;
1716 
1717 		/*
1718 		 * skip empty packets. At least M-Audio's Fast Track Ultra stops
1719 		 * streaming once it received a 0-byte OUT URB
1720 		 */
1721 		if (bytes == 0)
1722 			return;
1723 
1724 		spin_lock_irqsave(&ep->lock, flags);
1725 		if (ep->next_packet_queued >= ARRAY_SIZE(ep->next_packet)) {
1726 			spin_unlock_irqrestore(&ep->lock, flags);
1727 			usb_audio_err(ep->chip,
1728 				      "next package FIFO overflow EP 0x%x\n",
1729 				      ep->ep_num);
1730 			notify_xrun(ep);
1731 			return;
1732 		}
1733 
1734 		out_packet = next_packet_fifo_enqueue(ep);
1735 
1736 		/*
1737 		 * Iterate through the inbound packet and prepare the lengths
1738 		 * for the output packet. The OUT packet we are about to send
1739 		 * will have the same amount of payload bytes per stride as the
1740 		 * IN packet we just received. Since the actual size is scaled
1741 		 * by the stride, use the sender stride to calculate the length
1742 		 * in case the number of channels differ between the implicitly
1743 		 * fed-back endpoint and the synchronizing endpoint.
1744 		 */
1745 
1746 		out_packet->packets = in_ctx->packets;
1747 		for (i = 0; i < in_ctx->packets; i++) {
1748 			if (urb->iso_frame_desc[i].status == 0)
1749 				out_packet->packet_size[i] =
1750 					urb->iso_frame_desc[i].actual_length / sender->stride;
1751 			else
1752 				out_packet->packet_size[i] = 0;
1753 		}
1754 
1755 		spin_unlock_irqrestore(&ep->lock, flags);
1756 		snd_usb_queue_pending_output_urbs(ep, false);
1757 
1758 		return;
1759 	}
1760 
1761 	/*
1762 	 * process after playback sync complete
1763 	 *
1764 	 * Full speed devices report feedback values in 10.14 format as samples
1765 	 * per frame, high speed devices in 16.16 format as samples per
1766 	 * microframe.
1767 	 *
1768 	 * Because the Audio Class 1 spec was written before USB 2.0, many high
1769 	 * speed devices use a wrong interpretation, some others use an
1770 	 * entirely different format.
1771 	 *
1772 	 * Therefore, we cannot predict what format any particular device uses
1773 	 * and must detect it automatically.
1774 	 */
1775 
1776 	if (urb->iso_frame_desc[0].status != 0 ||
1777 	    urb->iso_frame_desc[0].actual_length < 3)
1778 		return;
1779 
1780 	f = le32_to_cpup(urb->transfer_buffer);
1781 	if (urb->iso_frame_desc[0].actual_length == 3)
1782 		f &= 0x00ffffff;
1783 	else
1784 		f &= 0x0fffffff;
1785 
1786 	if (f == 0)
1787 		return;
1788 
1789 	if (unlikely(sender->tenor_fb_quirk)) {
1790 		/*
1791 		 * Devices based on Tenor 8802 chipsets (TEAC UD-H01
1792 		 * and others) sometimes change the feedback value
1793 		 * by +/- 0x1.0000.
1794 		 */
1795 		if (f < ep->freqn - 0x8000)
1796 			f += 0xf000;
1797 		else if (f > ep->freqn + 0x8000)
1798 			f -= 0xf000;
1799 	} else if (unlikely(ep->freqshift == INT_MIN)) {
1800 		/*
1801 		 * The first time we see a feedback value, determine its format
1802 		 * by shifting it left or right until it matches the nominal
1803 		 * frequency value.  This assumes that the feedback does not
1804 		 * differ from the nominal value more than +50% or -25%.
1805 		 */
1806 		shift = 0;
1807 		while (f < ep->freqn - ep->freqn / 4) {
1808 			f <<= 1;
1809 			shift++;
1810 		}
1811 		while (f > ep->freqn + ep->freqn / 2) {
1812 			f >>= 1;
1813 			shift--;
1814 		}
1815 		ep->freqshift = shift;
1816 	} else if (ep->freqshift >= 0)
1817 		f <<= ep->freqshift;
1818 	else
1819 		f >>= -ep->freqshift;
1820 
1821 	if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1822 		/*
1823 		 * If the frequency looks valid, set it.
1824 		 * This value is referred to in prepare_playback_urb().
1825 		 */
1826 		spin_lock_irqsave(&ep->lock, flags);
1827 		ep->freqm = f;
1828 		spin_unlock_irqrestore(&ep->lock, flags);
1829 	} else {
1830 		/*
1831 		 * Out of range; maybe the shift value is wrong.
1832 		 * Reset it so that we autodetect again the next time.
1833 		 */
1834 		ep->freqshift = INT_MIN;
1835 	}
1836 }
1837 
1838