xref: /openbmc/linux/sound/usb/endpoint.c (revision 0c874100)
1 /*
2  *   This program is free software; you can redistribute it and/or modify
3  *   it under the terms of the GNU General Public License as published by
4  *   the Free Software Foundation; either version 2 of the License, or
5  *   (at your option) any later version.
6  *
7  *   This program is distributed in the hope that it will be useful,
8  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
9  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
10  *   GNU General Public License for more details.
11  *
12  *   You should have received a copy of the GNU General Public License
13  *   along with this program; if not, write to the Free Software
14  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
15  *
16  */
17 
18 #include <linux/gfp.h>
19 #include <linux/init.h>
20 #include <linux/ratelimit.h>
21 #include <linux/usb.h>
22 #include <linux/usb/audio.h>
23 #include <linux/slab.h>
24 
25 #include <sound/core.h>
26 #include <sound/pcm.h>
27 #include <sound/pcm_params.h>
28 
29 #include "usbaudio.h"
30 #include "helper.h"
31 #include "card.h"
32 #include "endpoint.h"
33 #include "pcm.h"
34 #include "quirks.h"
35 
36 #define EP_FLAG_RUNNING		1
37 #define EP_FLAG_STOPPING	2
38 
39 /*
40  * snd_usb_endpoint is a model that abstracts everything related to an
41  * USB endpoint and its streaming.
42  *
43  * There are functions to activate and deactivate the streaming URBs and
44  * optional callbacks to let the pcm logic handle the actual content of the
45  * packets for playback and record. Thus, the bus streaming and the audio
46  * handlers are fully decoupled.
47  *
48  * There are two different types of endpoints in audio applications.
49  *
50  * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
51  * inbound and outbound traffic.
52  *
53  * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
54  * expect the payload to carry Q10.14 / Q16.16 formatted sync information
55  * (3 or 4 bytes).
56  *
57  * Each endpoint has to be configured prior to being used by calling
58  * snd_usb_endpoint_set_params().
59  *
60  * The model incorporates a reference counting, so that multiple users
61  * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
62  * only the first user will effectively start the URBs, and only the last
63  * one to stop it will tear the URBs down again.
64  */
65 
66 /*
67  * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
68  * this will overflow at approx 524 kHz
69  */
70 static inline unsigned get_usb_full_speed_rate(unsigned int rate)
71 {
72 	return ((rate << 13) + 62) / 125;
73 }
74 
75 /*
76  * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
77  * this will overflow at approx 4 MHz
78  */
79 static inline unsigned get_usb_high_speed_rate(unsigned int rate)
80 {
81 	return ((rate << 10) + 62) / 125;
82 }
83 
84 /*
85  * release a urb data
86  */
87 static void release_urb_ctx(struct snd_urb_ctx *u)
88 {
89 	if (u->buffer_size)
90 		usb_free_coherent(u->ep->chip->dev, u->buffer_size,
91 				  u->urb->transfer_buffer,
92 				  u->urb->transfer_dma);
93 	usb_free_urb(u->urb);
94 	u->urb = NULL;
95 }
96 
97 static const char *usb_error_string(int err)
98 {
99 	switch (err) {
100 	case -ENODEV:
101 		return "no device";
102 	case -ENOENT:
103 		return "endpoint not enabled";
104 	case -EPIPE:
105 		return "endpoint stalled";
106 	case -ENOSPC:
107 		return "not enough bandwidth";
108 	case -ESHUTDOWN:
109 		return "device disabled";
110 	case -EHOSTUNREACH:
111 		return "device suspended";
112 	case -EINVAL:
113 	case -EAGAIN:
114 	case -EFBIG:
115 	case -EMSGSIZE:
116 		return "internal error";
117 	default:
118 		return "unknown error";
119 	}
120 }
121 
122 /**
123  * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
124  *
125  * @ep: The snd_usb_endpoint
126  *
127  * Determine whether an endpoint is driven by an implicit feedback
128  * data endpoint source.
129  */
130 int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
131 {
132 	return  ep->sync_master &&
133 		ep->sync_master->type == SND_USB_ENDPOINT_TYPE_DATA &&
134 		ep->type == SND_USB_ENDPOINT_TYPE_DATA &&
135 		usb_pipeout(ep->pipe);
136 }
137 
138 /*
139  * For streaming based on information derived from sync endpoints,
140  * prepare_outbound_urb_sizes() will call next_packet_size() to
141  * determine the number of samples to be sent in the next packet.
142  *
143  * For implicit feedback, next_packet_size() is unused.
144  */
145 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep)
146 {
147 	unsigned long flags;
148 	int ret;
149 
150 	if (ep->fill_max)
151 		return ep->maxframesize;
152 
153 	spin_lock_irqsave(&ep->lock, flags);
154 	ep->phase = (ep->phase & 0xffff)
155 		+ (ep->freqm << ep->datainterval);
156 	ret = min(ep->phase >> 16, ep->maxframesize);
157 	spin_unlock_irqrestore(&ep->lock, flags);
158 
159 	return ret;
160 }
161 
162 static void retire_outbound_urb(struct snd_usb_endpoint *ep,
163 				struct snd_urb_ctx *urb_ctx)
164 {
165 	if (ep->retire_data_urb)
166 		ep->retire_data_urb(ep->data_subs, urb_ctx->urb);
167 }
168 
169 static void retire_inbound_urb(struct snd_usb_endpoint *ep,
170 			       struct snd_urb_ctx *urb_ctx)
171 {
172 	struct urb *urb = urb_ctx->urb;
173 
174 	if (unlikely(ep->skip_packets > 0)) {
175 		ep->skip_packets--;
176 		return;
177 	}
178 
179 	if (ep->sync_slave)
180 		snd_usb_handle_sync_urb(ep->sync_slave, ep, urb);
181 
182 	if (ep->retire_data_urb)
183 		ep->retire_data_urb(ep->data_subs, urb);
184 }
185 
186 static void prepare_silent_urb(struct snd_usb_endpoint *ep,
187 			       struct snd_urb_ctx *ctx)
188 {
189 	struct urb *urb = ctx->urb;
190 	unsigned int offs = 0;
191 	unsigned int extra = 0;
192 	__le32 packet_length;
193 	int i;
194 
195 	/* For tx_length_quirk, put packet length at start of packet */
196 	if (ep->chip->tx_length_quirk)
197 		extra = sizeof(packet_length);
198 
199 	for (i = 0; i < ctx->packets; ++i) {
200 		unsigned int offset;
201 		unsigned int length;
202 		int counts;
203 
204 		if (ctx->packet_size[i])
205 			counts = ctx->packet_size[i];
206 		else
207 			counts = snd_usb_endpoint_next_packet_size(ep);
208 
209 		length = counts * ep->stride; /* number of silent bytes */
210 		offset = offs * ep->stride + extra * i;
211 		urb->iso_frame_desc[i].offset = offset;
212 		urb->iso_frame_desc[i].length = length + extra;
213 		if (extra) {
214 			packet_length = cpu_to_le32(length);
215 			memcpy(urb->transfer_buffer + offset,
216 			       &packet_length, sizeof(packet_length));
217 		}
218 		memset(urb->transfer_buffer + offset + extra,
219 		       ep->silence_value, length);
220 		offs += counts;
221 	}
222 
223 	urb->number_of_packets = ctx->packets;
224 	urb->transfer_buffer_length = offs * ep->stride + ctx->packets * extra;
225 }
226 
227 /*
228  * Prepare a PLAYBACK urb for submission to the bus.
229  */
230 static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
231 				 struct snd_urb_ctx *ctx)
232 {
233 	struct urb *urb = ctx->urb;
234 	unsigned char *cp = urb->transfer_buffer;
235 
236 	urb->dev = ep->chip->dev; /* we need to set this at each time */
237 
238 	switch (ep->type) {
239 	case SND_USB_ENDPOINT_TYPE_DATA:
240 		if (ep->prepare_data_urb) {
241 			ep->prepare_data_urb(ep->data_subs, urb);
242 		} else {
243 			/* no data provider, so send silence */
244 			prepare_silent_urb(ep, ctx);
245 		}
246 		break;
247 
248 	case SND_USB_ENDPOINT_TYPE_SYNC:
249 		if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
250 			/*
251 			 * fill the length and offset of each urb descriptor.
252 			 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
253 			 */
254 			urb->iso_frame_desc[0].length = 4;
255 			urb->iso_frame_desc[0].offset = 0;
256 			cp[0] = ep->freqn;
257 			cp[1] = ep->freqn >> 8;
258 			cp[2] = ep->freqn >> 16;
259 			cp[3] = ep->freqn >> 24;
260 		} else {
261 			/*
262 			 * fill the length and offset of each urb descriptor.
263 			 * the fixed 10.14 frequency is passed through the pipe.
264 			 */
265 			urb->iso_frame_desc[0].length = 3;
266 			urb->iso_frame_desc[0].offset = 0;
267 			cp[0] = ep->freqn >> 2;
268 			cp[1] = ep->freqn >> 10;
269 			cp[2] = ep->freqn >> 18;
270 		}
271 
272 		break;
273 	}
274 }
275 
276 /*
277  * Prepare a CAPTURE or SYNC urb for submission to the bus.
278  */
279 static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep,
280 				       struct snd_urb_ctx *urb_ctx)
281 {
282 	int i, offs;
283 	struct urb *urb = urb_ctx->urb;
284 
285 	urb->dev = ep->chip->dev; /* we need to set this at each time */
286 
287 	switch (ep->type) {
288 	case SND_USB_ENDPOINT_TYPE_DATA:
289 		offs = 0;
290 		for (i = 0; i < urb_ctx->packets; i++) {
291 			urb->iso_frame_desc[i].offset = offs;
292 			urb->iso_frame_desc[i].length = ep->curpacksize;
293 			offs += ep->curpacksize;
294 		}
295 
296 		urb->transfer_buffer_length = offs;
297 		urb->number_of_packets = urb_ctx->packets;
298 		break;
299 
300 	case SND_USB_ENDPOINT_TYPE_SYNC:
301 		urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
302 		urb->iso_frame_desc[0].offset = 0;
303 		break;
304 	}
305 }
306 
307 /*
308  * Send output urbs that have been prepared previously. URBs are dequeued
309  * from ep->ready_playback_urbs and in case there there aren't any available
310  * or there are no packets that have been prepared, this function does
311  * nothing.
312  *
313  * The reason why the functionality of sending and preparing URBs is separated
314  * is that host controllers don't guarantee the order in which they return
315  * inbound and outbound packets to their submitters.
316  *
317  * This function is only used for implicit feedback endpoints. For endpoints
318  * driven by dedicated sync endpoints, URBs are immediately re-submitted
319  * from their completion handler.
320  */
321 static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
322 {
323 	while (test_bit(EP_FLAG_RUNNING, &ep->flags)) {
324 
325 		unsigned long flags;
326 		struct snd_usb_packet_info *uninitialized_var(packet);
327 		struct snd_urb_ctx *ctx = NULL;
328 		int err, i;
329 
330 		spin_lock_irqsave(&ep->lock, flags);
331 		if (ep->next_packet_read_pos != ep->next_packet_write_pos) {
332 			packet = ep->next_packet + ep->next_packet_read_pos;
333 			ep->next_packet_read_pos++;
334 			ep->next_packet_read_pos %= MAX_URBS;
335 
336 			/* take URB out of FIFO */
337 			if (!list_empty(&ep->ready_playback_urbs))
338 				ctx = list_first_entry(&ep->ready_playback_urbs,
339 					       struct snd_urb_ctx, ready_list);
340 		}
341 		spin_unlock_irqrestore(&ep->lock, flags);
342 
343 		if (ctx == NULL)
344 			return;
345 
346 		list_del_init(&ctx->ready_list);
347 
348 		/* copy over the length information */
349 		for (i = 0; i < packet->packets; i++)
350 			ctx->packet_size[i] = packet->packet_size[i];
351 
352 		/* call the data handler to fill in playback data */
353 		prepare_outbound_urb(ep, ctx);
354 
355 		err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
356 		if (err < 0)
357 			usb_audio_err(ep->chip,
358 				"Unable to submit urb #%d: %d (urb %p)\n",
359 				ctx->index, err, ctx->urb);
360 		else
361 			set_bit(ctx->index, &ep->active_mask);
362 	}
363 }
364 
365 /*
366  * complete callback for urbs
367  */
368 static void snd_complete_urb(struct urb *urb)
369 {
370 	struct snd_urb_ctx *ctx = urb->context;
371 	struct snd_usb_endpoint *ep = ctx->ep;
372 	struct snd_pcm_substream *substream;
373 	unsigned long flags;
374 	int err;
375 
376 	if (unlikely(urb->status == -ENOENT ||		/* unlinked */
377 		     urb->status == -ENODEV ||		/* device removed */
378 		     urb->status == -ECONNRESET ||	/* unlinked */
379 		     urb->status == -ESHUTDOWN))	/* device disabled */
380 		goto exit_clear;
381 	/* device disconnected */
382 	if (unlikely(atomic_read(&ep->chip->shutdown)))
383 		goto exit_clear;
384 
385 	if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
386 		goto exit_clear;
387 
388 	if (usb_pipeout(ep->pipe)) {
389 		retire_outbound_urb(ep, ctx);
390 		/* can be stopped during retire callback */
391 		if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
392 			goto exit_clear;
393 
394 		if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
395 			spin_lock_irqsave(&ep->lock, flags);
396 			list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
397 			spin_unlock_irqrestore(&ep->lock, flags);
398 			queue_pending_output_urbs(ep);
399 
400 			goto exit_clear;
401 		}
402 
403 		prepare_outbound_urb(ep, ctx);
404 	} else {
405 		retire_inbound_urb(ep, ctx);
406 		/* can be stopped during retire callback */
407 		if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
408 			goto exit_clear;
409 
410 		prepare_inbound_urb(ep, ctx);
411 	}
412 
413 	err = usb_submit_urb(urb, GFP_ATOMIC);
414 	if (err == 0)
415 		return;
416 
417 	usb_audio_err(ep->chip, "cannot submit urb (err = %d)\n", err);
418 	if (ep->data_subs && ep->data_subs->pcm_substream) {
419 		substream = ep->data_subs->pcm_substream;
420 		snd_pcm_stop_xrun(substream);
421 	}
422 
423 exit_clear:
424 	clear_bit(ctx->index, &ep->active_mask);
425 }
426 
427 /**
428  * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
429  *
430  * @chip: The chip
431  * @alts: The USB host interface
432  * @ep_num: The number of the endpoint to use
433  * @direction: SNDRV_PCM_STREAM_PLAYBACK or SNDRV_PCM_STREAM_CAPTURE
434  * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
435  *
436  * If the requested endpoint has not been added to the given chip before,
437  * a new instance is created. Otherwise, a pointer to the previoulsy
438  * created instance is returned. In case of any error, NULL is returned.
439  *
440  * New endpoints will be added to chip->ep_list and must be freed by
441  * calling snd_usb_endpoint_free().
442  *
443  * For SND_USB_ENDPOINT_TYPE_SYNC, the caller needs to guarantee that
444  * bNumEndpoints > 1 beforehand.
445  */
446 struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
447 					      struct usb_host_interface *alts,
448 					      int ep_num, int direction, int type)
449 {
450 	struct snd_usb_endpoint *ep;
451 	int is_playback = direction == SNDRV_PCM_STREAM_PLAYBACK;
452 
453 	if (WARN_ON(!alts))
454 		return NULL;
455 
456 	mutex_lock(&chip->mutex);
457 
458 	list_for_each_entry(ep, &chip->ep_list, list) {
459 		if (ep->ep_num == ep_num &&
460 		    ep->iface == alts->desc.bInterfaceNumber &&
461 		    ep->altsetting == alts->desc.bAlternateSetting) {
462 			usb_audio_dbg(ep->chip,
463 				      "Re-using EP %x in iface %d,%d @%p\n",
464 					ep_num, ep->iface, ep->altsetting, ep);
465 			goto __exit_unlock;
466 		}
467 	}
468 
469 	usb_audio_dbg(chip, "Creating new %s %s endpoint #%x\n",
470 		    is_playback ? "playback" : "capture",
471 		    type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync",
472 		    ep_num);
473 
474 	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
475 	if (!ep)
476 		goto __exit_unlock;
477 
478 	ep->chip = chip;
479 	spin_lock_init(&ep->lock);
480 	ep->type = type;
481 	ep->ep_num = ep_num;
482 	ep->iface = alts->desc.bInterfaceNumber;
483 	ep->altsetting = alts->desc.bAlternateSetting;
484 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
485 	ep_num &= USB_ENDPOINT_NUMBER_MASK;
486 
487 	if (is_playback)
488 		ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
489 	else
490 		ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);
491 
492 	if (type == SND_USB_ENDPOINT_TYPE_SYNC) {
493 		if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
494 		    get_endpoint(alts, 1)->bRefresh >= 1 &&
495 		    get_endpoint(alts, 1)->bRefresh <= 9)
496 			ep->syncinterval = get_endpoint(alts, 1)->bRefresh;
497 		else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
498 			ep->syncinterval = 1;
499 		else if (get_endpoint(alts, 1)->bInterval >= 1 &&
500 			 get_endpoint(alts, 1)->bInterval <= 16)
501 			ep->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
502 		else
503 			ep->syncinterval = 3;
504 
505 		ep->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize);
506 	}
507 
508 	list_add_tail(&ep->list, &chip->ep_list);
509 
510 __exit_unlock:
511 	mutex_unlock(&chip->mutex);
512 
513 	return ep;
514 }
515 
516 /*
517  *  wait until all urbs are processed.
518  */
519 static int wait_clear_urbs(struct snd_usb_endpoint *ep)
520 {
521 	unsigned long end_time = jiffies + msecs_to_jiffies(1000);
522 	int alive;
523 
524 	do {
525 		alive = bitmap_weight(&ep->active_mask, ep->nurbs);
526 		if (!alive)
527 			break;
528 
529 		schedule_timeout_uninterruptible(1);
530 	} while (time_before(jiffies, end_time));
531 
532 	if (alive)
533 		usb_audio_err(ep->chip,
534 			"timeout: still %d active urbs on EP #%x\n",
535 			alive, ep->ep_num);
536 	clear_bit(EP_FLAG_STOPPING, &ep->flags);
537 
538 	ep->data_subs = NULL;
539 	ep->sync_slave = NULL;
540 	ep->retire_data_urb = NULL;
541 	ep->prepare_data_urb = NULL;
542 
543 	return 0;
544 }
545 
546 /* sync the pending stop operation;
547  * this function itself doesn't trigger the stop operation
548  */
549 void snd_usb_endpoint_sync_pending_stop(struct snd_usb_endpoint *ep)
550 {
551 	if (ep && test_bit(EP_FLAG_STOPPING, &ep->flags))
552 		wait_clear_urbs(ep);
553 }
554 
555 /*
556  * unlink active urbs.
557  */
558 static int deactivate_urbs(struct snd_usb_endpoint *ep, bool force)
559 {
560 	unsigned int i;
561 
562 	if (!force && atomic_read(&ep->chip->shutdown)) /* to be sure... */
563 		return -EBADFD;
564 
565 	clear_bit(EP_FLAG_RUNNING, &ep->flags);
566 
567 	INIT_LIST_HEAD(&ep->ready_playback_urbs);
568 	ep->next_packet_read_pos = 0;
569 	ep->next_packet_write_pos = 0;
570 
571 	for (i = 0; i < ep->nurbs; i++) {
572 		if (test_bit(i, &ep->active_mask)) {
573 			if (!test_and_set_bit(i, &ep->unlink_mask)) {
574 				struct urb *u = ep->urb[i].urb;
575 				usb_unlink_urb(u);
576 			}
577 		}
578 	}
579 
580 	return 0;
581 }
582 
583 /*
584  * release an endpoint's urbs
585  */
586 static void release_urbs(struct snd_usb_endpoint *ep, int force)
587 {
588 	int i;
589 
590 	/* route incoming urbs to nirvana */
591 	ep->retire_data_urb = NULL;
592 	ep->prepare_data_urb = NULL;
593 
594 	/* stop urbs */
595 	deactivate_urbs(ep, force);
596 	wait_clear_urbs(ep);
597 
598 	for (i = 0; i < ep->nurbs; i++)
599 		release_urb_ctx(&ep->urb[i]);
600 
601 	if (ep->syncbuf)
602 		usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
603 				  ep->syncbuf, ep->sync_dma);
604 
605 	ep->syncbuf = NULL;
606 	ep->nurbs = 0;
607 }
608 
609 /*
610  * configure a data endpoint
611  */
612 static int data_ep_set_params(struct snd_usb_endpoint *ep,
613 			      snd_pcm_format_t pcm_format,
614 			      unsigned int channels,
615 			      unsigned int period_bytes,
616 			      unsigned int frames_per_period,
617 			      unsigned int periods_per_buffer,
618 			      struct audioformat *fmt,
619 			      struct snd_usb_endpoint *sync_ep)
620 {
621 	unsigned int maxsize, minsize, packs_per_ms, max_packs_per_urb;
622 	unsigned int max_packs_per_period, urbs_per_period, urb_packs;
623 	unsigned int max_urbs, i;
624 	int frame_bits = snd_pcm_format_physical_width(pcm_format) * channels;
625 	int tx_length_quirk = (ep->chip->tx_length_quirk &&
626 			       usb_pipeout(ep->pipe));
627 
628 	if (pcm_format == SNDRV_PCM_FORMAT_DSD_U16_LE && fmt->dsd_dop) {
629 		/*
630 		 * When operating in DSD DOP mode, the size of a sample frame
631 		 * in hardware differs from the actual physical format width
632 		 * because we need to make room for the DOP markers.
633 		 */
634 		frame_bits += channels << 3;
635 	}
636 
637 	ep->datainterval = fmt->datainterval;
638 	ep->stride = frame_bits >> 3;
639 
640 	switch (pcm_format) {
641 	case SNDRV_PCM_FORMAT_U8:
642 		ep->silence_value = 0x80;
643 		break;
644 	case SNDRV_PCM_FORMAT_DSD_U8:
645 	case SNDRV_PCM_FORMAT_DSD_U16_LE:
646 	case SNDRV_PCM_FORMAT_DSD_U32_LE:
647 	case SNDRV_PCM_FORMAT_DSD_U16_BE:
648 	case SNDRV_PCM_FORMAT_DSD_U32_BE:
649 		ep->silence_value = 0x69;
650 		break;
651 	default:
652 		ep->silence_value = 0;
653 	}
654 
655 	/* assume max. frequency is 50% higher than nominal */
656 	ep->freqmax = ep->freqn + (ep->freqn >> 1);
657 	/* Round up freqmax to nearest integer in order to calculate maximum
658 	 * packet size, which must represent a whole number of frames.
659 	 * This is accomplished by adding 0x0.ffff before converting the
660 	 * Q16.16 format into integer.
661 	 * In order to accurately calculate the maximum packet size when
662 	 * the data interval is more than 1 (i.e. ep->datainterval > 0),
663 	 * multiply by the data interval prior to rounding. For instance,
664 	 * a freqmax of 41 kHz will result in a max packet size of 6 (5.125)
665 	 * frames with a data interval of 1, but 11 (10.25) frames with a
666 	 * data interval of 2.
667 	 * (ep->freqmax << ep->datainterval overflows at 8.192 MHz for the
668 	 * maximum datainterval value of 3, at USB full speed, higher for
669 	 * USB high speed, noting that ep->freqmax is in units of
670 	 * frames per packet in Q16.16 format.)
671 	 */
672 	maxsize = (((ep->freqmax << ep->datainterval) + 0xffff) >> 16) *
673 			 (frame_bits >> 3);
674 	if (tx_length_quirk)
675 		maxsize += sizeof(__le32); /* Space for length descriptor */
676 	/* but wMaxPacketSize might reduce this */
677 	if (ep->maxpacksize && ep->maxpacksize < maxsize) {
678 		/* whatever fits into a max. size packet */
679 		unsigned int data_maxsize = maxsize = ep->maxpacksize;
680 
681 		if (tx_length_quirk)
682 			/* Need to remove the length descriptor to calc freq */
683 			data_maxsize -= sizeof(__le32);
684 		ep->freqmax = (data_maxsize / (frame_bits >> 3))
685 				<< (16 - ep->datainterval);
686 	}
687 
688 	if (ep->fill_max)
689 		ep->curpacksize = ep->maxpacksize;
690 	else
691 		ep->curpacksize = maxsize;
692 
693 	if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL) {
694 		packs_per_ms = 8 >> ep->datainterval;
695 		max_packs_per_urb = MAX_PACKS_HS;
696 	} else {
697 		packs_per_ms = 1;
698 		max_packs_per_urb = MAX_PACKS;
699 	}
700 	if (sync_ep && !snd_usb_endpoint_implicit_feedback_sink(ep))
701 		max_packs_per_urb = min(max_packs_per_urb,
702 					1U << sync_ep->syncinterval);
703 	max_packs_per_urb = max(1u, max_packs_per_urb >> ep->datainterval);
704 
705 	/*
706 	 * Capture endpoints need to use small URBs because there's no way
707 	 * to tell in advance where the next period will end, and we don't
708 	 * want the next URB to complete much after the period ends.
709 	 *
710 	 * Playback endpoints with implicit sync much use the same parameters
711 	 * as their corresponding capture endpoint.
712 	 */
713 	if (usb_pipein(ep->pipe) ||
714 			snd_usb_endpoint_implicit_feedback_sink(ep)) {
715 
716 		urb_packs = packs_per_ms;
717 		/*
718 		 * Wireless devices can poll at a max rate of once per 4ms.
719 		 * For dataintervals less than 5, increase the packet count to
720 		 * allow the host controller to use bursting to fill in the
721 		 * gaps.
722 		 */
723 		if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_WIRELESS) {
724 			int interval = ep->datainterval;
725 			while (interval < 5) {
726 				urb_packs <<= 1;
727 				++interval;
728 			}
729 		}
730 		/* make capture URBs <= 1 ms and smaller than a period */
731 		urb_packs = min(max_packs_per_urb, urb_packs);
732 		while (urb_packs > 1 && urb_packs * maxsize >= period_bytes)
733 			urb_packs >>= 1;
734 		ep->nurbs = MAX_URBS;
735 
736 	/*
737 	 * Playback endpoints without implicit sync are adjusted so that
738 	 * a period fits as evenly as possible in the smallest number of
739 	 * URBs.  The total number of URBs is adjusted to the size of the
740 	 * ALSA buffer, subject to the MAX_URBS and MAX_QUEUE limits.
741 	 */
742 	} else {
743 		/* determine how small a packet can be */
744 		minsize = (ep->freqn >> (16 - ep->datainterval)) *
745 				(frame_bits >> 3);
746 		/* with sync from device, assume it can be 12% lower */
747 		if (sync_ep)
748 			minsize -= minsize >> 3;
749 		minsize = max(minsize, 1u);
750 
751 		/* how many packets will contain an entire ALSA period? */
752 		max_packs_per_period = DIV_ROUND_UP(period_bytes, minsize);
753 
754 		/* how many URBs will contain a period? */
755 		urbs_per_period = DIV_ROUND_UP(max_packs_per_period,
756 				max_packs_per_urb);
757 		/* how many packets are needed in each URB? */
758 		urb_packs = DIV_ROUND_UP(max_packs_per_period, urbs_per_period);
759 
760 		/* limit the number of frames in a single URB */
761 		ep->max_urb_frames = DIV_ROUND_UP(frames_per_period,
762 					urbs_per_period);
763 
764 		/* try to use enough URBs to contain an entire ALSA buffer */
765 		max_urbs = min((unsigned) MAX_URBS,
766 				MAX_QUEUE * packs_per_ms / urb_packs);
767 		ep->nurbs = min(max_urbs, urbs_per_period * periods_per_buffer);
768 	}
769 
770 	/* allocate and initialize data urbs */
771 	for (i = 0; i < ep->nurbs; i++) {
772 		struct snd_urb_ctx *u = &ep->urb[i];
773 		u->index = i;
774 		u->ep = ep;
775 		u->packets = urb_packs;
776 		u->buffer_size = maxsize * u->packets;
777 
778 		if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
779 			u->packets++; /* for transfer delimiter */
780 		u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
781 		if (!u->urb)
782 			goto out_of_memory;
783 
784 		u->urb->transfer_buffer =
785 			usb_alloc_coherent(ep->chip->dev, u->buffer_size,
786 					   GFP_KERNEL, &u->urb->transfer_dma);
787 		if (!u->urb->transfer_buffer)
788 			goto out_of_memory;
789 		u->urb->pipe = ep->pipe;
790 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
791 		u->urb->interval = 1 << ep->datainterval;
792 		u->urb->context = u;
793 		u->urb->complete = snd_complete_urb;
794 		INIT_LIST_HEAD(&u->ready_list);
795 	}
796 
797 	return 0;
798 
799 out_of_memory:
800 	release_urbs(ep, 0);
801 	return -ENOMEM;
802 }
803 
804 /*
805  * configure a sync endpoint
806  */
807 static int sync_ep_set_params(struct snd_usb_endpoint *ep)
808 {
809 	int i;
810 
811 	ep->syncbuf = usb_alloc_coherent(ep->chip->dev, SYNC_URBS * 4,
812 					 GFP_KERNEL, &ep->sync_dma);
813 	if (!ep->syncbuf)
814 		return -ENOMEM;
815 
816 	for (i = 0; i < SYNC_URBS; i++) {
817 		struct snd_urb_ctx *u = &ep->urb[i];
818 		u->index = i;
819 		u->ep = ep;
820 		u->packets = 1;
821 		u->urb = usb_alloc_urb(1, GFP_KERNEL);
822 		if (!u->urb)
823 			goto out_of_memory;
824 		u->urb->transfer_buffer = ep->syncbuf + i * 4;
825 		u->urb->transfer_dma = ep->sync_dma + i * 4;
826 		u->urb->transfer_buffer_length = 4;
827 		u->urb->pipe = ep->pipe;
828 		u->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
829 		u->urb->number_of_packets = 1;
830 		u->urb->interval = 1 << ep->syncinterval;
831 		u->urb->context = u;
832 		u->urb->complete = snd_complete_urb;
833 	}
834 
835 	ep->nurbs = SYNC_URBS;
836 
837 	return 0;
838 
839 out_of_memory:
840 	release_urbs(ep, 0);
841 	return -ENOMEM;
842 }
843 
844 /**
845  * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
846  *
847  * @ep: the snd_usb_endpoint to configure
848  * @pcm_format: the audio fomat.
849  * @channels: the number of audio channels.
850  * @period_bytes: the number of bytes in one alsa period.
851  * @period_frames: the number of frames in one alsa period.
852  * @buffer_periods: the number of periods in one alsa buffer.
853  * @rate: the frame rate.
854  * @fmt: the USB audio format information
855  * @sync_ep: the sync endpoint to use, if any
856  *
857  * Determine the number of URBs to be used on this endpoint.
858  * An endpoint must be configured before it can be started.
859  * An endpoint that is already running can not be reconfigured.
860  */
861 int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
862 				snd_pcm_format_t pcm_format,
863 				unsigned int channels,
864 				unsigned int period_bytes,
865 				unsigned int period_frames,
866 				unsigned int buffer_periods,
867 				unsigned int rate,
868 				struct audioformat *fmt,
869 				struct snd_usb_endpoint *sync_ep)
870 {
871 	int err;
872 
873 	if (ep->use_count != 0) {
874 		usb_audio_warn(ep->chip,
875 			 "Unable to change format on ep #%x: already in use\n",
876 			 ep->ep_num);
877 		return -EBUSY;
878 	}
879 
880 	/* release old buffers, if any */
881 	release_urbs(ep, 0);
882 
883 	ep->datainterval = fmt->datainterval;
884 	ep->maxpacksize = fmt->maxpacksize;
885 	ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
886 
887 	if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL)
888 		ep->freqn = get_usb_full_speed_rate(rate);
889 	else
890 		ep->freqn = get_usb_high_speed_rate(rate);
891 
892 	/* calculate the frequency in 16.16 format */
893 	ep->freqm = ep->freqn;
894 	ep->freqshift = INT_MIN;
895 
896 	ep->phase = 0;
897 
898 	switch (ep->type) {
899 	case  SND_USB_ENDPOINT_TYPE_DATA:
900 		err = data_ep_set_params(ep, pcm_format, channels,
901 					 period_bytes, period_frames,
902 					 buffer_periods, fmt, sync_ep);
903 		break;
904 	case  SND_USB_ENDPOINT_TYPE_SYNC:
905 		err = sync_ep_set_params(ep);
906 		break;
907 	default:
908 		err = -EINVAL;
909 	}
910 
911 	usb_audio_dbg(ep->chip,
912 		"Setting params for ep #%x (type %d, %d urbs), ret=%d\n",
913 		ep->ep_num, ep->type, ep->nurbs, err);
914 
915 	return err;
916 }
917 
918 /**
919  * snd_usb_endpoint_start: start an snd_usb_endpoint
920  *
921  * @ep: the endpoint to start
922  *
923  * A call to this function will increment the use count of the endpoint.
924  * In case it is not already running, the URBs for this endpoint will be
925  * submitted. Otherwise, this function does nothing.
926  *
927  * Must be balanced to calls of snd_usb_endpoint_stop().
928  *
929  * Returns an error if the URB submission failed, 0 in all other cases.
930  */
931 int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
932 {
933 	int err;
934 	unsigned int i;
935 
936 	if (atomic_read(&ep->chip->shutdown))
937 		return -EBADFD;
938 
939 	/* already running? */
940 	if (++ep->use_count != 1)
941 		return 0;
942 
943 	/* just to be sure */
944 	deactivate_urbs(ep, false);
945 
946 	ep->active_mask = 0;
947 	ep->unlink_mask = 0;
948 	ep->phase = 0;
949 
950 	snd_usb_endpoint_start_quirk(ep);
951 
952 	/*
953 	 * If this endpoint has a data endpoint as implicit feedback source,
954 	 * don't start the urbs here. Instead, mark them all as available,
955 	 * wait for the record urbs to return and queue the playback urbs
956 	 * from that context.
957 	 */
958 
959 	set_bit(EP_FLAG_RUNNING, &ep->flags);
960 
961 	if (snd_usb_endpoint_implicit_feedback_sink(ep)) {
962 		for (i = 0; i < ep->nurbs; i++) {
963 			struct snd_urb_ctx *ctx = ep->urb + i;
964 			list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
965 		}
966 
967 		return 0;
968 	}
969 
970 	for (i = 0; i < ep->nurbs; i++) {
971 		struct urb *urb = ep->urb[i].urb;
972 
973 		if (snd_BUG_ON(!urb))
974 			goto __error;
975 
976 		if (usb_pipeout(ep->pipe)) {
977 			prepare_outbound_urb(ep, urb->context);
978 		} else {
979 			prepare_inbound_urb(ep, urb->context);
980 		}
981 
982 		err = usb_submit_urb(urb, GFP_ATOMIC);
983 		if (err < 0) {
984 			usb_audio_err(ep->chip,
985 				"cannot submit urb %d, error %d: %s\n",
986 				i, err, usb_error_string(err));
987 			goto __error;
988 		}
989 		set_bit(i, &ep->active_mask);
990 	}
991 
992 	return 0;
993 
994 __error:
995 	clear_bit(EP_FLAG_RUNNING, &ep->flags);
996 	ep->use_count--;
997 	deactivate_urbs(ep, false);
998 	return -EPIPE;
999 }
1000 
1001 /**
1002  * snd_usb_endpoint_stop: stop an snd_usb_endpoint
1003  *
1004  * @ep: the endpoint to stop (may be NULL)
1005  *
1006  * A call to this function will decrement the use count of the endpoint.
1007  * In case the last user has requested the endpoint stop, the URBs will
1008  * actually be deactivated.
1009  *
1010  * Must be balanced to calls of snd_usb_endpoint_start().
1011  *
1012  * The caller needs to synchronize the pending stop operation via
1013  * snd_usb_endpoint_sync_pending_stop().
1014  */
1015 void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep)
1016 {
1017 	if (!ep)
1018 		return;
1019 
1020 	if (snd_BUG_ON(ep->use_count == 0))
1021 		return;
1022 
1023 	if (--ep->use_count == 0) {
1024 		deactivate_urbs(ep, false);
1025 		set_bit(EP_FLAG_STOPPING, &ep->flags);
1026 	}
1027 }
1028 
1029 /**
1030  * snd_usb_endpoint_deactivate: deactivate an snd_usb_endpoint
1031  *
1032  * @ep: the endpoint to deactivate
1033  *
1034  * If the endpoint is not currently in use, this functions will
1035  * deactivate its associated URBs.
1036  *
1037  * In case of any active users, this functions does nothing.
1038  */
1039 void snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep)
1040 {
1041 	if (!ep)
1042 		return;
1043 
1044 	if (ep->use_count != 0)
1045 		return;
1046 
1047 	deactivate_urbs(ep, true);
1048 	wait_clear_urbs(ep);
1049 }
1050 
1051 /**
1052  * snd_usb_endpoint_release: Tear down an snd_usb_endpoint
1053  *
1054  * @ep: the endpoint to release
1055  *
1056  * This function does not care for the endpoint's use count but will tear
1057  * down all the streaming URBs immediately.
1058  */
1059 void snd_usb_endpoint_release(struct snd_usb_endpoint *ep)
1060 {
1061 	release_urbs(ep, 1);
1062 }
1063 
1064 /**
1065  * snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint
1066  *
1067  * @ep: the endpoint to free
1068  *
1069  * This free all resources of the given ep.
1070  */
1071 void snd_usb_endpoint_free(struct snd_usb_endpoint *ep)
1072 {
1073 	kfree(ep);
1074 }
1075 
1076 /**
1077  * snd_usb_handle_sync_urb: parse an USB sync packet
1078  *
1079  * @ep: the endpoint to handle the packet
1080  * @sender: the sending endpoint
1081  * @urb: the received packet
1082  *
1083  * This function is called from the context of an endpoint that received
1084  * the packet and is used to let another endpoint object handle the payload.
1085  */
1086 void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
1087 			     struct snd_usb_endpoint *sender,
1088 			     const struct urb *urb)
1089 {
1090 	int shift;
1091 	unsigned int f;
1092 	unsigned long flags;
1093 
1094 	snd_BUG_ON(ep == sender);
1095 
1096 	/*
1097 	 * In case the endpoint is operating in implicit feedback mode, prepare
1098 	 * a new outbound URB that has the same layout as the received packet
1099 	 * and add it to the list of pending urbs. queue_pending_output_urbs()
1100 	 * will take care of them later.
1101 	 */
1102 	if (snd_usb_endpoint_implicit_feedback_sink(ep) &&
1103 	    ep->use_count != 0) {
1104 
1105 		/* implicit feedback case */
1106 		int i, bytes = 0;
1107 		struct snd_urb_ctx *in_ctx;
1108 		struct snd_usb_packet_info *out_packet;
1109 
1110 		in_ctx = urb->context;
1111 
1112 		/* Count overall packet size */
1113 		for (i = 0; i < in_ctx->packets; i++)
1114 			if (urb->iso_frame_desc[i].status == 0)
1115 				bytes += urb->iso_frame_desc[i].actual_length;
1116 
1117 		/*
1118 		 * skip empty packets. At least M-Audio's Fast Track Ultra stops
1119 		 * streaming once it received a 0-byte OUT URB
1120 		 */
1121 		if (bytes == 0)
1122 			return;
1123 
1124 		spin_lock_irqsave(&ep->lock, flags);
1125 		out_packet = ep->next_packet + ep->next_packet_write_pos;
1126 
1127 		/*
1128 		 * Iterate through the inbound packet and prepare the lengths
1129 		 * for the output packet. The OUT packet we are about to send
1130 		 * will have the same amount of payload bytes per stride as the
1131 		 * IN packet we just received. Since the actual size is scaled
1132 		 * by the stride, use the sender stride to calculate the length
1133 		 * in case the number of channels differ between the implicitly
1134 		 * fed-back endpoint and the synchronizing endpoint.
1135 		 */
1136 
1137 		out_packet->packets = in_ctx->packets;
1138 		for (i = 0; i < in_ctx->packets; i++) {
1139 			if (urb->iso_frame_desc[i].status == 0)
1140 				out_packet->packet_size[i] =
1141 					urb->iso_frame_desc[i].actual_length / sender->stride;
1142 			else
1143 				out_packet->packet_size[i] = 0;
1144 		}
1145 
1146 		ep->next_packet_write_pos++;
1147 		ep->next_packet_write_pos %= MAX_URBS;
1148 		spin_unlock_irqrestore(&ep->lock, flags);
1149 		queue_pending_output_urbs(ep);
1150 
1151 		return;
1152 	}
1153 
1154 	/*
1155 	 * process after playback sync complete
1156 	 *
1157 	 * Full speed devices report feedback values in 10.14 format as samples
1158 	 * per frame, high speed devices in 16.16 format as samples per
1159 	 * microframe.
1160 	 *
1161 	 * Because the Audio Class 1 spec was written before USB 2.0, many high
1162 	 * speed devices use a wrong interpretation, some others use an
1163 	 * entirely different format.
1164 	 *
1165 	 * Therefore, we cannot predict what format any particular device uses
1166 	 * and must detect it automatically.
1167 	 */
1168 
1169 	if (urb->iso_frame_desc[0].status != 0 ||
1170 	    urb->iso_frame_desc[0].actual_length < 3)
1171 		return;
1172 
1173 	f = le32_to_cpup(urb->transfer_buffer);
1174 	if (urb->iso_frame_desc[0].actual_length == 3)
1175 		f &= 0x00ffffff;
1176 	else
1177 		f &= 0x0fffffff;
1178 
1179 	if (f == 0)
1180 		return;
1181 
1182 	if (unlikely(sender->tenor_fb_quirk)) {
1183 		/*
1184 		 * Devices based on Tenor 8802 chipsets (TEAC UD-H01
1185 		 * and others) sometimes change the feedback value
1186 		 * by +/- 0x1.0000.
1187 		 */
1188 		if (f < ep->freqn - 0x8000)
1189 			f += 0xf000;
1190 		else if (f > ep->freqn + 0x8000)
1191 			f -= 0xf000;
1192 	} else if (unlikely(ep->freqshift == INT_MIN)) {
1193 		/*
1194 		 * The first time we see a feedback value, determine its format
1195 		 * by shifting it left or right until it matches the nominal
1196 		 * frequency value.  This assumes that the feedback does not
1197 		 * differ from the nominal value more than +50% or -25%.
1198 		 */
1199 		shift = 0;
1200 		while (f < ep->freqn - ep->freqn / 4) {
1201 			f <<= 1;
1202 			shift++;
1203 		}
1204 		while (f > ep->freqn + ep->freqn / 2) {
1205 			f >>= 1;
1206 			shift--;
1207 		}
1208 		ep->freqshift = shift;
1209 	} else if (ep->freqshift >= 0)
1210 		f <<= ep->freqshift;
1211 	else
1212 		f >>= -ep->freqshift;
1213 
1214 	if (likely(f >= ep->freqn - ep->freqn / 8 && f <= ep->freqmax)) {
1215 		/*
1216 		 * If the frequency looks valid, set it.
1217 		 * This value is referred to in prepare_playback_urb().
1218 		 */
1219 		spin_lock_irqsave(&ep->lock, flags);
1220 		ep->freqm = f;
1221 		spin_unlock_irqrestore(&ep->lock, flags);
1222 	} else {
1223 		/*
1224 		 * Out of range; maybe the shift value is wrong.
1225 		 * Reset it so that we autodetect again the next time.
1226 		 */
1227 		ep->freqshift = INT_MIN;
1228 	}
1229 }
1230 
1231