endpoint.c 28.7 KB
Newer Older
Daniel Mack's avatar
Daniel Mack committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
/*
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

18
19
#include <linux/gfp.h>
#include <linux/init.h>
20
#include <linux/ratelimit.h>
21
22
#include <linux/usb.h>
#include <linux/usb/audio.h>
23
#include <linux/slab.h>
24
25
26

#include <sound/core.h>
#include <sound/pcm.h>
27
#include <sound/pcm_params.h>
28
29
30
31
32
33

#include "usbaudio.h"
#include "helper.h"
#include "card.h"
#include "endpoint.h"
#include "pcm.h"
34
#include "quirks.h"
35

36
37
38
#define EP_FLAG_ACTIVATED	0
#define EP_FLAG_RUNNING		1

39
40
41
42
43
/*
 * snd_usb_endpoint is a model that abstracts everything related to an
 * USB endpoint and its streaming.
 *
 * 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
46
47
 * packets for playback and record. Thus, the bus streaming and the audio
 * handlers are fully decoupled.
 *
48
 * There are two different types of endpoints in audio applications.
49
50
51
52
 *
 * SND_USB_ENDPOINT_TYPE_DATA handles full audio data payload for both
 * inbound and outbound traffic.
 *
53
54
55
 * SND_USB_ENDPOINT_TYPE_SYNC endpoints are for inbound traffic only and
 * expect the payload to carry Q10.14 / Q16.16 formatted sync information
 * (3 or 4 bytes).
56
 *
57
58
 * Each endpoint has to be configured prior to being used by calling
 * snd_usb_endpoint_set_params().
59
60
61
62
 *
 * The model incorporates a reference counting, so that multiple users
 * can call snd_usb_endpoint_start() and snd_usb_endpoint_stop(), and
 * 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
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
/*
 * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
 * this will overflow at approx 524 kHz
 */
static inline unsigned get_usb_full_speed_rate(unsigned int rate)
{
	return ((rate << 13) + 62) / 125;
}

/*
 * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
 * this will overflow at approx 4 MHz
 */
static inline unsigned get_usb_high_speed_rate(unsigned int rate)
{
	return ((rate << 10) + 62) / 125;
}

/*
 * release a urb data
 */
static void release_urb_ctx(struct snd_urb_ctx *u)
{
89
90
91
92
93
94
	if (u->buffer_size)
		usb_free_coherent(u->ep->chip->dev, u->buffer_size,
				  u->urb->transfer_buffer,
				  u->urb->transfer_dma);
	usb_free_urb(u->urb);
	u->urb = NULL;
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
}

static const char *usb_error_string(int err)
{
	switch (err) {
	case -ENODEV:
		return "no device";
	case -ENOENT:
		return "endpoint not enabled";
	case -EPIPE:
		return "endpoint stalled";
	case -ENOSPC:
		return "not enough bandwidth";
	case -ESHUTDOWN:
		return "device disabled";
	case -EHOSTUNREACH:
		return "device suspended";
	case -EINVAL:
	case -EAGAIN:
	case -EFBIG:
	case -EMSGSIZE:
		return "internal error";
	default:
		return "unknown error";
	}
}

122
123
124
/**
 * snd_usb_endpoint_implicit_feedback_sink: Report endpoint usage type
 *
125
 * @ep: The snd_usb_endpoint
126
127
128
129
 *
 * Determine whether an endpoint is driven by an implicit feedback
 * data endpoint source.
 */
130
131
132
133
134
135
136
137
int snd_usb_endpoint_implict_feedback_sink(struct snd_usb_endpoint *ep)
{
	return  ep->sync_master &&
		ep->sync_master->type == SND_USB_ENDPOINT_TYPE_DATA &&
		ep->type == SND_USB_ENDPOINT_TYPE_DATA &&
		usb_pipeout(ep->pipe);
}

138
139
140
141
142
143
144
/*
 * For streaming based on information derived from sync endpoints,
 * prepare_outbound_urb_sizes() will call next_packet_size() to
 * determine the number of samples to be sent in the next packet.
 *
 * For implicit feedback, next_packet_size() is unused.
 */
145
int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep)
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
{
	unsigned long flags;
	int ret;

	if (ep->fill_max)
		return ep->maxframesize;

	spin_lock_irqsave(&ep->lock, flags);
	ep->phase = (ep->phase & 0xffff)
		+ (ep->freqm << ep->datainterval);
	ret = min(ep->phase >> 16, ep->maxframesize);
	spin_unlock_irqrestore(&ep->lock, flags);

	return ret;
}

static void retire_outbound_urb(struct snd_usb_endpoint *ep,
				struct snd_urb_ctx *urb_ctx)
{
	if (ep->retire_data_urb)
		ep->retire_data_urb(ep->data_subs, urb_ctx->urb);
}

static void retire_inbound_urb(struct snd_usb_endpoint *ep,
			       struct snd_urb_ctx *urb_ctx)
{
	struct urb *urb = urb_ctx->urb;

174
175
176
177
178
	if (unlikely(ep->skip_packets > 0)) {
		ep->skip_packets--;
		return;
	}

179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
	if (ep->sync_slave)
		snd_usb_handle_sync_urb(ep->sync_slave, ep, urb);

	if (ep->retire_data_urb)
		ep->retire_data_urb(ep->data_subs, urb);
}

/*
 * Prepare a PLAYBACK urb for submission to the bus.
 */
static void prepare_outbound_urb(struct snd_usb_endpoint *ep,
				 struct snd_urb_ctx *ctx)
{
	int i;
	struct urb *urb = ctx->urb;
	unsigned char *cp = urb->transfer_buffer;

	urb->dev = ep->chip->dev; /* we need to set this at each time */

	switch (ep->type) {
	case SND_USB_ENDPOINT_TYPE_DATA:
		if (ep->prepare_data_urb) {
			ep->prepare_data_urb(ep->data_subs, urb);
		} else {
			/* no data provider, so send silence */
			unsigned int offs = 0;
			for (i = 0; i < ctx->packets; ++i) {
206
207
208
209
210
211
212
				int counts;

				if (ctx->packet_size[i])
					counts = ctx->packet_size[i];
				else
					counts = snd_usb_endpoint_next_packet_size(ep);

213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
				urb->iso_frame_desc[i].offset = offs * ep->stride;
				urb->iso_frame_desc[i].length = counts * ep->stride;
				offs += counts;
			}

			urb->number_of_packets = ctx->packets;
			urb->transfer_buffer_length = offs * ep->stride;
			memset(urb->transfer_buffer, ep->silence_value,
			       offs * ep->stride);
		}
		break;

	case SND_USB_ENDPOINT_TYPE_SYNC:
		if (snd_usb_get_speed(ep->chip->dev) >= USB_SPEED_HIGH) {
			/*
			 * fill the length and offset of each urb descriptor.
			 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
			 */
			urb->iso_frame_desc[0].length = 4;
			urb->iso_frame_desc[0].offset = 0;
			cp[0] = ep->freqn;
			cp[1] = ep->freqn >> 8;
			cp[2] = ep->freqn >> 16;
			cp[3] = ep->freqn >> 24;
		} else {
			/*
			 * fill the length and offset of each urb descriptor.
			 * the fixed 10.14 frequency is passed through the pipe.
			 */
			urb->iso_frame_desc[0].length = 3;
			urb->iso_frame_desc[0].offset = 0;
			cp[0] = ep->freqn >> 2;
			cp[1] = ep->freqn >> 10;
			cp[2] = ep->freqn >> 18;
		}

		break;
	}
}

/*
 * Prepare a CAPTURE or SYNC urb for submission to the bus.
 */
static inline void prepare_inbound_urb(struct snd_usb_endpoint *ep,
				       struct snd_urb_ctx *urb_ctx)
{
	int i, offs;
	struct urb *urb = urb_ctx->urb;

	urb->dev = ep->chip->dev; /* we need to set this at each time */

	switch (ep->type) {
	case SND_USB_ENDPOINT_TYPE_DATA:
		offs = 0;
		for (i = 0; i < urb_ctx->packets; i++) {
			urb->iso_frame_desc[i].offset = offs;
			urb->iso_frame_desc[i].length = ep->curpacksize;
			offs += ep->curpacksize;
		}

		urb->transfer_buffer_length = offs;
		urb->number_of_packets = urb_ctx->packets;
		break;

	case SND_USB_ENDPOINT_TYPE_SYNC:
		urb->iso_frame_desc[0].length = min(4u, ep->syncmaxsize);
		urb->iso_frame_desc[0].offset = 0;
		break;
	}
}

284
/*
285
 * Send output urbs that have been prepared previously. URBs are dequeued
286
287
288
289
 * from ep->ready_playback_urbs and in case there there aren't any available
 * or there are no packets that have been prepared, this function does
 * nothing.
 *
290
291
292
 * The reason why the functionality of sending and preparing URBs is separated
 * is that host controllers don't guarantee the order in which they return
 * inbound and outbound packets to their submitters.
293
294
 *
 * This function is only used for implicit feedback endpoints. For endpoints
295
296
 * driven by dedicated sync endpoints, URBs are immediately re-submitted
 * from their completion handler.
297
 */
298
299
300
301
302
static void queue_pending_output_urbs(struct snd_usb_endpoint *ep)
{
	while (test_bit(EP_FLAG_RUNNING, &ep->flags)) {

		unsigned long flags;
303
		struct snd_usb_packet_info *uninitialized_var(packet);
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
		struct snd_urb_ctx *ctx = NULL;
		struct urb *urb;
		int err, i;

		spin_lock_irqsave(&ep->lock, flags);
		if (ep->next_packet_read_pos != ep->next_packet_write_pos) {
			packet = ep->next_packet + ep->next_packet_read_pos;
			ep->next_packet_read_pos++;
			ep->next_packet_read_pos %= MAX_URBS;

			/* take URB out of FIFO */
			if (!list_empty(&ep->ready_playback_urbs))
				ctx = list_first_entry(&ep->ready_playback_urbs,
					       struct snd_urb_ctx, ready_list);
		}
		spin_unlock_irqrestore(&ep->lock, flags);

		if (ctx == NULL)
			return;

		list_del_init(&ctx->ready_list);
		urb = ctx->urb;

		/* copy over the length information */
		for (i = 0; i < packet->packets; i++)
			ctx->packet_size[i] = packet->packet_size[i];

331
		/* call the data handler to fill in playback data */
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
		prepare_outbound_urb(ep, ctx);

		err = usb_submit_urb(ctx->urb, GFP_ATOMIC);
		if (err < 0)
			snd_printk(KERN_ERR "Unable to submit urb #%d: %d (urb %p)\n",
				   ctx->index, err, ctx->urb);
		else
			set_bit(ctx->index, &ep->active_mask);
	}
}

/*
 * complete callback for urbs
 */
static void snd_complete_urb(struct urb *urb)
{
	struct snd_urb_ctx *ctx = urb->context;
	struct snd_usb_endpoint *ep = ctx->ep;
	int err;

	if (unlikely(urb->status == -ENOENT ||		/* unlinked */
		     urb->status == -ENODEV ||		/* device removed */
		     urb->status == -ECONNRESET ||	/* unlinked */
		     urb->status == -ESHUTDOWN ||	/* device disabled */
		     ep->chip->shutdown))		/* device disconnected */
		goto exit_clear;

	if (usb_pipeout(ep->pipe)) {
		retire_outbound_urb(ep, ctx);
		/* can be stopped during retire callback */
		if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
			goto exit_clear;

		if (snd_usb_endpoint_implict_feedback_sink(ep)) {
			unsigned long flags;

			spin_lock_irqsave(&ep->lock, flags);
			list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
			spin_unlock_irqrestore(&ep->lock, flags);
			queue_pending_output_urbs(ep);

			goto exit_clear;
		}

		prepare_outbound_urb(ep, ctx);
	} else {
		retire_inbound_urb(ep, ctx);
		/* can be stopped during retire callback */
		if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags)))
			goto exit_clear;

		prepare_inbound_urb(ep, ctx);
	}

	err = usb_submit_urb(urb, GFP_ATOMIC);
	if (err == 0)
		return;

	snd_printk(KERN_ERR "cannot submit urb (err = %d)\n", err);
	//snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);

exit_clear:
	clear_bit(ctx->index, &ep->active_mask);
}

397
/**
398
 * snd_usb_add_endpoint: Add an endpoint to an USB audio chip
399
400
401
402
403
404
405
406
407
408
409
410
411
412
 *
 * @chip: The chip
 * @alts: The USB host interface
 * @ep_num: The number of the endpoint to use
 * @direction: SNDRV_PCM_STREAM_PLAYBACK or SNDRV_PCM_STREAM_CAPTURE
 * @type: SND_USB_ENDPOINT_TYPE_DATA or SND_USB_ENDPOINT_TYPE_SYNC
 *
 * If the requested endpoint has not been added to the given chip before,
 * a new instance is created. Otherwise, a pointer to the previoulsy
 * created instance is returned. In case of any error, NULL is returned.
 *
 * New endpoints will be added to chip->ep_list and must be freed by
 * calling snd_usb_endpoint_free().
 */
413
414
415
416
417
418
struct snd_usb_endpoint *snd_usb_add_endpoint(struct snd_usb_audio *chip,
					      struct usb_host_interface *alts,
					      int ep_num, int direction, int type)
{
	struct list_head *p;
	struct snd_usb_endpoint *ep;
419
	int is_playback = direction == SNDRV_PCM_STREAM_PLAYBACK;
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571

	mutex_lock(&chip->mutex);

	list_for_each(p, &chip->ep_list) {
		ep = list_entry(p, struct snd_usb_endpoint, list);
		if (ep->ep_num == ep_num &&
		    ep->iface == alts->desc.bInterfaceNumber &&
		    ep->alt_idx == alts->desc.bAlternateSetting) {
			snd_printdd(KERN_DEBUG "Re-using EP %x in iface %d,%d @%p\n",
					ep_num, ep->iface, ep->alt_idx, ep);
			goto __exit_unlock;
		}
	}

	snd_printdd(KERN_DEBUG "Creating new %s %s endpoint #%x\n",
		    is_playback ? "playback" : "capture",
		    type == SND_USB_ENDPOINT_TYPE_DATA ? "data" : "sync",
		    ep_num);

	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
	if (!ep)
		goto __exit_unlock;

	ep->chip = chip;
	spin_lock_init(&ep->lock);
	ep->type = type;
	ep->ep_num = ep_num;
	ep->iface = alts->desc.bInterfaceNumber;
	ep->alt_idx = alts->desc.bAlternateSetting;
	INIT_LIST_HEAD(&ep->ready_playback_urbs);
	ep_num &= USB_ENDPOINT_NUMBER_MASK;

	if (is_playback)
		ep->pipe = usb_sndisocpipe(chip->dev, ep_num);
	else
		ep->pipe = usb_rcvisocpipe(chip->dev, ep_num);

	if (type == SND_USB_ENDPOINT_TYPE_SYNC) {
		if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
		    get_endpoint(alts, 1)->bRefresh >= 1 &&
		    get_endpoint(alts, 1)->bRefresh <= 9)
			ep->syncinterval = get_endpoint(alts, 1)->bRefresh;
		else if (snd_usb_get_speed(chip->dev) == USB_SPEED_FULL)
			ep->syncinterval = 1;
		else if (get_endpoint(alts, 1)->bInterval >= 1 &&
			 get_endpoint(alts, 1)->bInterval <= 16)
			ep->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
		else
			ep->syncinterval = 3;

		ep->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize);
	}

	list_add_tail(&ep->list, &chip->ep_list);

__exit_unlock:
	mutex_unlock(&chip->mutex);

	return ep;
}

/*
 *  wait until all urbs are processed.
 */
static int wait_clear_urbs(struct snd_usb_endpoint *ep)
{
	unsigned long end_time = jiffies + msecs_to_jiffies(1000);
	unsigned int i;
	int alive;

	do {
		alive = 0;
		for (i = 0; i < ep->nurbs; i++)
			if (test_bit(i, &ep->active_mask))
				alive++;

		if (!alive)
			break;

		schedule_timeout_uninterruptible(1);
	} while (time_before(jiffies, end_time));

	if (alive)
		snd_printk(KERN_ERR "timeout: still %d active urbs on EP #%x\n",
					alive, ep->ep_num);

	return 0;
}

/*
 * unlink active urbs.
 */
static int deactivate_urbs(struct snd_usb_endpoint *ep, int force, int can_sleep)
{
	unsigned int i;
	int async;

	if (!force && ep->chip->shutdown) /* to be sure... */
		return -EBADFD;

	async = !can_sleep && ep->chip->async_unlink;

	clear_bit(EP_FLAG_RUNNING, &ep->flags);

	INIT_LIST_HEAD(&ep->ready_playback_urbs);
	ep->next_packet_read_pos = 0;
	ep->next_packet_write_pos = 0;

	if (!async && in_interrupt())
		return 0;

	for (i = 0; i < ep->nurbs; i++) {
		if (test_bit(i, &ep->active_mask)) {
			if (!test_and_set_bit(i, &ep->unlink_mask)) {
				struct urb *u = ep->urb[i].urb;
				if (async)
					usb_unlink_urb(u);
				else
					usb_kill_urb(u);
			}
		}
	}

	return 0;
}

/*
 * release an endpoint's urbs
 */
static void release_urbs(struct snd_usb_endpoint *ep, int force)
{
	int i;

	/* route incoming urbs to nirvana */
	ep->retire_data_urb = NULL;
	ep->prepare_data_urb = NULL;

	/* stop urbs */
	deactivate_urbs(ep, force, 1);
	wait_clear_urbs(ep);

	for (i = 0; i < ep->nurbs; i++)
		release_urb_ctx(&ep->urb[i]);

	if (ep->syncbuf)
		usb_free_coherent(ep->chip->dev, SYNC_URBS * 4,
				  ep->syncbuf, ep->sync_dma);

	ep->syncbuf = NULL;
	ep->nurbs = 0;
}

572
573
574
/*
 * configure a data endpoint
 */
575
static int data_ep_set_params(struct snd_usb_endpoint *ep,
576
577
578
			      snd_pcm_format_t pcm_format,
			      unsigned int channels,
			      unsigned int period_bytes,
579
580
581
582
583
			      struct audioformat *fmt,
			      struct snd_usb_endpoint *sync_ep)
{
	unsigned int maxsize, i, urb_packs, total_packs, packs_per_ms;
	int is_playback = usb_pipeout(ep->pipe);
584
	int frame_bits = snd_pcm_format_physical_width(pcm_format) * channels;
585
586
587

	ep->datainterval = fmt->datainterval;
	ep->stride = frame_bits >> 3;
588
	ep->silence_value = pcm_format == SNDRV_PCM_FORMAT_U8 ? 0x80 : 0;
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696

	/* calculate max. frequency */
	if (ep->maxpacksize) {
		/* whatever fits into a max. size packet */
		maxsize = ep->maxpacksize;
		ep->freqmax = (maxsize / (frame_bits >> 3))
				<< (16 - ep->datainterval);
	} else {
		/* no max. packet size: just take 25% higher than nominal */
		ep->freqmax = ep->freqn + (ep->freqn >> 2);
		maxsize = ((ep->freqmax + 0xffff) * (frame_bits >> 3))
				>> (16 - ep->datainterval);
	}

	if (ep->fill_max)
		ep->curpacksize = ep->maxpacksize;
	else
		ep->curpacksize = maxsize;

	if (snd_usb_get_speed(ep->chip->dev) != USB_SPEED_FULL)
		packs_per_ms = 8 >> ep->datainterval;
	else
		packs_per_ms = 1;

	if (is_playback && !snd_usb_endpoint_implict_feedback_sink(ep)) {
		urb_packs = max(ep->chip->nrpacks, 1);
		urb_packs = min(urb_packs, (unsigned int) MAX_PACKS);
	} else {
		urb_packs = 1;
	}

	urb_packs *= packs_per_ms;

	if (sync_ep && !snd_usb_endpoint_implict_feedback_sink(ep))
		urb_packs = min(urb_packs, 1U << sync_ep->syncinterval);

	/* decide how many packets to be used */
	if (is_playback && !snd_usb_endpoint_implict_feedback_sink(ep)) {
		unsigned int minsize, maxpacks;
		/* determine how small a packet can be */
		minsize = (ep->freqn >> (16 - ep->datainterval))
			  * (frame_bits >> 3);
		/* with sync from device, assume it can be 12% lower */
		if (sync_ep)
			minsize -= minsize >> 3;
		minsize = max(minsize, 1u);
		total_packs = (period_bytes + minsize - 1) / minsize;
		/* we need at least two URBs for queueing */
		if (total_packs < 2) {
			total_packs = 2;
		} else {
			/* and we don't want too long a queue either */
			maxpacks = max(MAX_QUEUE * packs_per_ms, urb_packs * 2);
			total_packs = min(total_packs, maxpacks);
		}
	} else {
		while (urb_packs > 1 && urb_packs * maxsize >= period_bytes)
			urb_packs >>= 1;
		total_packs = MAX_URBS * urb_packs;
	}

	ep->nurbs = (total_packs + urb_packs - 1) / urb_packs;
	if (ep->nurbs > MAX_URBS) {
		/* too much... */
		ep->nurbs = MAX_URBS;
		total_packs = MAX_URBS * urb_packs;
	} else if (ep->nurbs < 2) {
		/* too little - we need at least two packets
		 * to ensure contiguous playback/capture
		 */
		ep->nurbs = 2;
	}

	/* allocate and initialize data urbs */
	for (i = 0; i < ep->nurbs; i++) {
		struct snd_urb_ctx *u = &ep->urb[i];
		u->index = i;
		u->ep = ep;
		u->packets = (i + 1) * total_packs / ep->nurbs
			- i * total_packs / ep->nurbs;
		u->buffer_size = maxsize * u->packets;

		if (fmt->fmt_type == UAC_FORMAT_TYPE_II)
			u->packets++; /* for transfer delimiter */
		u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
		if (!u->urb)
			goto out_of_memory;

		u->urb->transfer_buffer =
			usb_alloc_coherent(ep->chip->dev, u->buffer_size,
					   GFP_KERNEL, &u->urb->transfer_dma);
		if (!u->urb->transfer_buffer)
			goto out_of_memory;
		u->urb->pipe = ep->pipe;
		u->urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
		u->urb->interval = 1 << ep->datainterval;
		u->urb->context = u;
		u->urb->complete = snd_complete_urb;
		INIT_LIST_HEAD(&u->ready_list);
	}

	return 0;

out_of_memory:
	release_urbs(ep, 0);
	return -ENOMEM;
}

697
698
699
/*
 * configure a sync endpoint
 */
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
static int sync_ep_set_params(struct snd_usb_endpoint *ep,
			      struct audioformat *fmt)
{
	int i;

	ep->syncbuf = usb_alloc_coherent(ep->chip->dev, SYNC_URBS * 4,
					 GFP_KERNEL, &ep->sync_dma);
	if (!ep->syncbuf)
		return -ENOMEM;

	for (i = 0; i < SYNC_URBS; i++) {
		struct snd_urb_ctx *u = &ep->urb[i];
		u->index = i;
		u->ep = ep;
		u->packets = 1;
		u->urb = usb_alloc_urb(1, GFP_KERNEL);
		if (!u->urb)
			goto out_of_memory;
		u->urb->transfer_buffer = ep->syncbuf + i * 4;
		u->urb->transfer_dma = ep->sync_dma + i * 4;
		u->urb->transfer_buffer_length = 4;
		u->urb->pipe = ep->pipe;
		u->urb->transfer_flags = URB_ISO_ASAP |
					 URB_NO_TRANSFER_DMA_MAP;
		u->urb->number_of_packets = 1;
		u->urb->interval = 1 << ep->syncinterval;
		u->urb->context = u;
		u->urb->complete = snd_complete_urb;
	}

	ep->nurbs = SYNC_URBS;

	return 0;

out_of_memory:
	release_urbs(ep, 0);
	return -ENOMEM;
}

739
/**
740
 * snd_usb_endpoint_set_params: configure an snd_usb_endpoint
741
 *
742
 * @ep: the snd_usb_endpoint to configure
743
744
745
746
 * @pcm_format: the audio fomat.
 * @channels: the number of audio channels.
 * @period_bytes: the number of bytes in one alsa period.
 * @rate: the frame rate.
747
748
 * @fmt: the USB audio format information
 * @sync_ep: the sync endpoint to use, if any
749
 *
750
 * Determine the number of URBs to be used on this endpoint.
751
752
753
 * An endpoint must be configured before it can be started.
 * An endpoint that is already running can not be reconfigured.
 */
754
int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
755
756
757
758
				snd_pcm_format_t pcm_format,
				unsigned int channels,
				unsigned int period_bytes,
				unsigned int rate,
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
				struct audioformat *fmt,
				struct snd_usb_endpoint *sync_ep)
{
	int err;

	if (ep->use_count != 0) {
		snd_printk(KERN_WARNING "Unable to change format on ep #%x: already in use\n",
			   ep->ep_num);
		return -EBUSY;
	}

	/* release old buffers, if any */
	release_urbs(ep, 0);

	ep->datainterval = fmt->datainterval;
	ep->maxpacksize = fmt->maxpacksize;
775
	ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
776
777

	if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL)
778
		ep->freqn = get_usb_full_speed_rate(rate);
779
	else
780
		ep->freqn = get_usb_high_speed_rate(rate);
781
782
783
784
785
786
787
788
789

	/* calculate the frequency in 16.16 format */
	ep->freqm = ep->freqn;
	ep->freqshift = INT_MIN;

	ep->phase = 0;

	switch (ep->type) {
	case  SND_USB_ENDPOINT_TYPE_DATA:
790
791
		err = data_ep_set_params(ep, pcm_format, channels,
					 period_bytes, fmt, sync_ep);
792
793
		break;
	case  SND_USB_ENDPOINT_TYPE_SYNC:
794
		err = sync_ep_set_params(ep, fmt);
795
796
797
798
799
800
801
802
803
804
805
		break;
	default:
		err = -EINVAL;
	}

	snd_printdd(KERN_DEBUG "Setting params for ep #%x (type %d, %d urbs), ret=%d\n",
		   ep->ep_num, ep->type, ep->nurbs, err);

	return err;
}

806
807
808
/**
 * snd_usb_endpoint_start: start an snd_usb_endpoint
 *
809
810
811
 * @ep:		the endpoint to start
 * @can_sleep:	flag indicating whether the operation is executed in
 * 		non-atomic context
812
813
 *
 * A call to this function will increment the use count of the endpoint.
814
 * In case it is not already running, the URBs for this endpoint will be
815
816
817
818
819
820
 * submitted. Otherwise, this function does nothing.
 *
 * Must be balanced to calls of snd_usb_endpoint_stop().
 *
 * Returns an error if the URB submission failed, 0 in all other cases.
 */
821
int snd_usb_endpoint_start(struct snd_usb_endpoint *ep, int can_sleep)
822
823
824
825
826
827
828
829
830
831
832
{
	int err;
	unsigned int i;

	if (ep->chip->shutdown)
		return -EBADFD;

	/* already running? */
	if (++ep->use_count != 1)
		return 0;

833
834
835
836
837
	/* just to be sure */
	deactivate_urbs(ep, 0, can_sleep);
	if (can_sleep)
		wait_clear_urbs(ep);

838
839
840
841
	ep->active_mask = 0;
	ep->unlink_mask = 0;
	ep->phase = 0;

842
843
	snd_usb_endpoint_start_quirk(ep);

844
845
846
	/*
	 * If this endpoint has a data endpoint as implicit feedback source,
	 * don't start the urbs here. Instead, mark them all as available,
847
848
	 * wait for the record urbs to return and queue the playback urbs
	 * from that context.
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
	 */

	set_bit(EP_FLAG_RUNNING, &ep->flags);

	if (snd_usb_endpoint_implict_feedback_sink(ep)) {
		for (i = 0; i < ep->nurbs; i++) {
			struct snd_urb_ctx *ctx = ep->urb + i;
			list_add_tail(&ctx->ready_list, &ep->ready_playback_urbs);
		}

		return 0;
	}

	for (i = 0; i < ep->nurbs; i++) {
		struct urb *urb = ep->urb[i].urb;

		if (snd_BUG_ON(!urb))
			goto __error;

		if (usb_pipeout(ep->pipe)) {
			prepare_outbound_urb(ep, urb->context);
		} else {
			prepare_inbound_urb(ep, urb->context);
		}

		err = usb_submit_urb(urb, GFP_ATOMIC);
		if (err < 0) {
			snd_printk(KERN_ERR "cannot submit urb %d, error %d: %s\n",
				   i, err, usb_error_string(err));
			goto __error;
		}
		set_bit(i, &ep->active_mask);
	}

	return 0;

__error:
	clear_bit(EP_FLAG_RUNNING, &ep->flags);
	ep->use_count--;
	deactivate_urbs(ep, 0, 0);
	return -EPIPE;
}

892
893
894
895
896
897
898
/**
 * snd_usb_endpoint_stop: stop an snd_usb_endpoint
 *
 * @ep: the endpoint to stop (may be NULL)
 *
 * A call to this function will decrement the use count of the endpoint.
 * In case the last user has requested the endpoint stop, the URBs will
899
 * actually be deactivated.
900
901
902
 *
 * Must be balanced to calls of snd_usb_endpoint_start().
 */
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep,
			   int force, int can_sleep, int wait)
{
	if (!ep)
		return;

	if (snd_BUG_ON(ep->use_count == 0))
		return;

	if (--ep->use_count == 0) {
		deactivate_urbs(ep, force, can_sleep);
		ep->data_subs = NULL;
		ep->sync_slave = NULL;
		ep->retire_data_urb = NULL;
		ep->prepare_data_urb = NULL;

		if (wait)
			wait_clear_urbs(ep);
	}
}

924
925
926
927
928
929
930
931
932
933
934
935
936
/**
 * snd_usb_endpoint_deactivate: deactivate an snd_usb_endpoint
 *
 * @ep: the endpoint to deactivate
 *
 * If the endpoint is not currently in use, this functions will select the
 * alternate interface setting 0 for the interface of this endpoint.
 *
 * In case of any active users, this functions does nothing.
 *
 * Returns an error if usb_set_interface() failed, 0 in all other
 * cases.
 */
937
938
939
940
941
int snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep)
{
	if (!ep)
		return -EINVAL;

942
943
944
	deactivate_urbs(ep, 1, 1);
	wait_clear_urbs(ep);

945
946
947
	if (ep->use_count != 0)
		return 0;

948
	clear_bit(EP_FLAG_ACTIVATED, &ep->flags);
949

950
	return 0;
951
952
}

953
954
/**
 * snd_usb_endpoint_free: Free the resources of an snd_usb_endpoint
955
956
957
958
959
960
 *
 * @ep: the list header of the endpoint to free
 *
 * This function does not care for the endpoint's use count but will tear
 * down all the streaming URBs immediately and free all resources.
 */
961
962
963
964
965
966
967
968
969
void snd_usb_endpoint_free(struct list_head *head)
{
	struct snd_usb_endpoint *ep;

	ep = list_entry(head, struct snd_usb_endpoint, list);
	release_urbs(ep, 1);
	kfree(ep);
}

970
971
972
973
974
975
976
977
978
/**
 * snd_usb_handle_sync_urb: parse an USB sync packet
 *
 * @ep: the endpoint to handle the packet
 * @sender: the sending endpoint
 * @urb: the received packet
 *
 * This function is called from the context of an endpoint that received
 * the packet and is used to let another endpoint object handle the payload.
979
980
981
982
983
984
985
986
987
988
989
 */
void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,
			     struct snd_usb_endpoint *sender,
			     const struct urb *urb)
{
	int shift;
	unsigned int f;
	unsigned long flags;

	snd_BUG_ON(ep == sender);

990
991
	/*
	 * In case the endpoint is operating in implicit feedback mode, prepare
992
993
994
	 * a new outbound URB that has the same layout as the received packet
	 * and add it to the list of pending urbs. queue_pending_output_urbs()
	 * will take care of them later.
995
	 */
996
997
998
999
1000
	if (snd_usb_endpoint_implict_feedback_sink(ep) &&
	    ep->use_count != 0) {

		/* implicit feedback case */
		int i, bytes = 0;