aboutsummaryrefslogtreecommitdiff
path: root/sound/usb/urb.c
blob: e184349aee83f1e5a790deb43238186dab2b3355 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
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
89
90
91
92
93
94
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
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
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
174
175
176
177
178
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
206
207
208
209
210
211
212
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
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
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
331
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
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
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
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
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
697
698
699
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
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
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
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
/*
 *   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
 *
 */

#include <linux/gfp.h>
#include <linux/init.h>
#include <linux/usb.h>
#include <linux/usb/audio.h>

#include <sound/core.h>
#include <sound/pcm.h>

#include "usbaudio.h"
#include "helper.h"
#include "card.h"
#include "urb.h"
#include "pcm.h"

/*
 * 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;
}

/*
 * unlink active urbs.
 */
static int deactivate_urbs(struct snd_usb_substream *subs, int force, int can_sleep)
{
	struct snd_usb_audio *chip = subs->stream->chip;
	unsigned int i;
	int async;

	subs->running = 0;

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

	async = !can_sleep && chip->async_unlink;

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

	for (i = 0; i < subs->nurbs; i++) {
		if (test_bit(i, &subs->active_mask)) {
			if (!test_and_set_bit(i, &subs->unlink_mask)) {
				struct urb *u = subs->dataurb[i].urb;
				if (async)
					usb_unlink_urb(u);
				else
					usb_kill_urb(u);
			}
		}
	}
	if (subs->syncpipe) {
		for (i = 0; i < SYNC_URBS; i++) {
			if (test_bit(i+16, &subs->active_mask)) {
				if (!test_and_set_bit(i+16, &subs->unlink_mask)) {
					struct urb *u = subs->syncurb[i].urb;
					if (async)
						usb_unlink_urb(u);
					else
						usb_kill_urb(u);
				}
			}
		}
	}
	return 0;
}


/*
 * release a urb data
 */
static void release_urb_ctx(struct snd_urb_ctx *u)
{
	if (u->urb) {
		if (u->buffer_size)
			usb_free_coherent(u->subs->dev, u->buffer_size,
					u->urb->transfer_buffer,
					u->urb->transfer_dma);
		usb_free_urb(u->urb);
		u->urb = NULL;
	}
}

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

	do {
		alive = 0;
		for (i = 0; i < subs->nurbs; i++) {
			if (test_bit(i, &subs->active_mask))
				alive++;
		}
		if (subs->syncpipe) {
			for (i = 0; i < SYNC_URBS; i++) {
				if (test_bit(i + 16, &subs->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..\n", alive);
	return 0;
}

/*
 * release a substream
 */
void snd_usb_release_substream_urbs(struct snd_usb_substream *subs, int force)
{
	int i;

	/* stop urbs (to be sure) */
	deactivate_urbs(subs, force, 1);
	wait_clear_urbs(subs);

	for (i = 0; i < MAX_URBS; i++)
		release_urb_ctx(&subs->dataurb[i]);
	for (i = 0; i < SYNC_URBS; i++)
		release_urb_ctx(&subs->syncurb[i]);
	usb_free_coherent(subs->dev, SYNC_URBS * 4,
			subs->syncbuf, subs->sync_dma);
	subs->syncbuf = NULL;
	subs->nurbs = 0;
}

/*
 * complete callback from data urb
 */
static void snd_complete_urb(struct urb *urb)
{
	struct snd_urb_ctx *ctx = urb->context;
	struct snd_usb_substream *subs = ctx->subs;
	struct snd_pcm_substream *substream = ctx->subs->pcm_substream;
	int err = 0;

	if ((subs->running && subs->ops.retire(subs, substream->runtime, urb)) ||
	    !subs->running || /* can be stopped during retire callback */
	    (err = subs->ops.prepare(subs, substream->runtime, urb)) < 0 ||
	    (err = usb_submit_urb(urb, GFP_ATOMIC)) < 0) {
		clear_bit(ctx->index, &subs->active_mask);
		if (err < 0) {
			snd_printd(KERN_ERR "cannot submit urb (err = %d)\n", err);
			snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
		}
	}
}


/*
 * complete callback from sync urb
 */
static void snd_complete_sync_urb(struct urb *urb)
{
	struct snd_urb_ctx *ctx = urb->context;
	struct snd_usb_substream *subs = ctx->subs;
	struct snd_pcm_substream *substream = ctx->subs->pcm_substream;
	int err = 0;

	if ((subs->running && subs->ops.retire_sync(subs, substream->runtime, urb)) ||
	    !subs->running || /* can be stopped during retire callback */
	    (err = subs->ops.prepare_sync(subs, substream->runtime, urb)) < 0 ||
	    (err = usb_submit_urb(urb, GFP_ATOMIC)) < 0) {
		clear_bit(ctx->index + 16, &subs->active_mask);
		if (err < 0) {
			snd_printd(KERN_ERR "cannot submit sync urb (err = %d)\n", err);
			snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
		}
	}
}


/*
 * initialize a substream for plaback/capture
 */
int snd_usb_init_substream_urbs(struct snd_usb_substream *subs,
				unsigned int period_bytes,
				unsigned int rate,
				unsigned int frame_bits)
{
	unsigned int maxsize, i;
	int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
	unsigned int urb_packs, total_packs, packs_per_ms;
	struct snd_usb_audio *chip = subs->stream->chip;

	/* calculate the frequency in 16.16 format */
	if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
		subs->freqn = get_usb_full_speed_rate(rate);
	else
		subs->freqn = get_usb_high_speed_rate(rate);
	subs->freqm = subs->freqn;
	subs->freqshift = INT_MIN;
	/* calculate max. frequency */
	if (subs->maxpacksize) {
		/* whatever fits into a max. size packet */
		maxsize = subs->maxpacksize;
		subs->freqmax = (maxsize / (frame_bits >> 3))
				<< (16 - subs->datainterval);
	} else {
		/* no max. packet size: just take 25% higher than nominal */
		subs->freqmax = subs->freqn + (subs->freqn >> 2);
		maxsize = ((subs->freqmax + 0xffff) * (frame_bits >> 3))
				>> (16 - subs->datainterval);
	}
	subs->phase = 0;

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

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

	if (is_playback) {
		urb_packs = max(chip->nrpacks, 1);
		urb_packs = min(urb_packs, (unsigned int)MAX_PACKS);
	} else
		urb_packs = 1;
	urb_packs *= packs_per_ms;
	if (subs->syncpipe)
		urb_packs = min(urb_packs, 1U << subs->syncinterval);

	/* decide how many packets to be used */
	if (is_playback) {
		unsigned int minsize, maxpacks;
		/* determine how small a packet can be */
		minsize = (subs->freqn >> (16 - subs->datainterval))
			  * (frame_bits >> 3);
		/* with sync from device, assume it can be 12% lower */
		if (subs->syncpipe)
			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;
	}
	subs->nurbs = (total_packs + urb_packs - 1) / urb_packs;
	if (subs->nurbs > MAX_URBS) {
		/* too much... */
		subs->nurbs = MAX_URBS;
		total_packs = MAX_URBS * urb_packs;
	} else if (subs->nurbs < 2) {
		/* too little - we need at least two packets
		 * to ensure contiguous playback/capture
		 */
		subs->nurbs = 2;
	}

	/* allocate and initialize data urbs */
	for (i = 0; i < subs->nurbs; i++) {
		struct snd_urb_ctx *u = &subs->dataurb[i];
		u->index = i;
		u->subs = subs;
		u->packets = (i + 1) * total_packs / subs->nurbs
			- i * total_packs / subs->nurbs;
		u->buffer_size = maxsize * u->packets;
		if (subs->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(subs->dev, u->buffer_size,
					   GFP_KERNEL, &u->urb->transfer_dma);
		if (!u->urb->transfer_buffer)
			goto out_of_memory;
		u->urb->pipe = subs->datapipe;
		u->urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
		u->urb->interval = 1 << subs->datainterval;
		u->urb->context = u;
		u->urb->complete = snd_complete_urb;
	}

	if (subs->syncpipe) {
		/* allocate and initialize sync urbs */
		subs->syncbuf = usb_alloc_coherent(subs->dev, SYNC_URBS * 4,
						 GFP_KERNEL, &subs->sync_dma);
		if (!subs->syncbuf)
			goto out_of_memory;
		for (i = 0; i < SYNC_URBS; i++) {
			struct snd_urb_ctx *u = &subs->syncurb[i];
			u->index = i;
			u->subs = subs;
			u->packets = 1;
			u->urb = usb_alloc_urb(1, GFP_KERNEL);
			if (!u->urb)
				goto out_of_memory;
			u->urb->transfer_buffer = subs->syncbuf + i * 4;
			u->urb->transfer_dma = subs->sync_dma + i * 4;
			u->urb->transfer_buffer_length = 4;
			u->urb->pipe = subs->syncpipe;
			u->urb->transfer_flags = URB_ISO_ASAP |
						 URB_NO_TRANSFER_DMA_MAP;
			u->urb->number_of_packets = 1;
			u->urb->interval = 1 << subs->syncinterval;
			u->urb->context = u;
			u->urb->complete = snd_complete_sync_urb;
		}
	}
	return 0;

out_of_memory:
	snd_usb_release_substream_urbs(subs, 0);
	return -ENOMEM;
}

/*
 * prepare urb for full speed capture sync pipe
 *
 * fill the length and offset of each urb descriptor.
 * the fixed 10.14 frequency is passed through the pipe.
 */
static int prepare_capture_sync_urb(struct snd_usb_substream *subs,
				    struct snd_pcm_runtime *runtime,
				    struct urb *urb)
{
	unsigned char *cp = urb->transfer_buffer;
	struct snd_urb_ctx *ctx = urb->context;

	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	urb->iso_frame_desc[0].length = 3;
	urb->iso_frame_desc[0].offset = 0;
	cp[0] = subs->freqn >> 2;
	cp[1] = subs->freqn >> 10;
	cp[2] = subs->freqn >> 18;
	return 0;
}

/*
 * prepare urb for high speed capture sync pipe
 *
 * fill the length and offset of each urb descriptor.
 * the fixed 12.13 frequency is passed as 16.16 through the pipe.
 */
static int prepare_capture_sync_urb_hs(struct snd_usb_substream *subs,
				       struct snd_pcm_runtime *runtime,
				       struct urb *urb)
{
	unsigned char *cp = urb->transfer_buffer;
	struct snd_urb_ctx *ctx = urb->context;

	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	urb->iso_frame_desc[0].length = 4;
	urb->iso_frame_desc[0].offset = 0;
	cp[0] = subs->freqn;
	cp[1] = subs->freqn >> 8;
	cp[2] = subs->freqn >> 16;
	cp[3] = subs->freqn >> 24;
	return 0;
}

/*
 * process after capture sync complete
 * - nothing to do
 */
static int retire_capture_sync_urb(struct snd_usb_substream *subs,
				   struct snd_pcm_runtime *runtime,
				   struct urb *urb)
{
	return 0;
}

/*
 * prepare urb for capture data pipe
 *
 * fill the offset and length of each descriptor.
 *
 * we use a temporary buffer to write the captured data.
 * since the length of written data is determined by host, we cannot
 * write onto the pcm buffer directly...  the data is thus copied
 * later at complete callback to the global buffer.
 */
static int prepare_capture_urb(struct snd_usb_substream *subs,
			       struct snd_pcm_runtime *runtime,
			       struct urb *urb)
{
	int i, offs;
	struct snd_urb_ctx *ctx = urb->context;

	offs = 0;
	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	for (i = 0; i < ctx->packets; i++) {
		urb->iso_frame_desc[i].offset = offs;
		urb->iso_frame_desc[i].length = subs->curpacksize;
		offs += subs->curpacksize;
	}
	urb->transfer_buffer_length = offs;
	urb->number_of_packets = ctx->packets;
	return 0;
}

/*
 * process after capture complete
 *
 * copy the data from each desctiptor to the pcm buffer, and
 * update the current position.
 */
static int retire_capture_urb(struct snd_usb_substream *subs,
			      struct snd_pcm_runtime *runtime,
			      struct urb *urb)
{
	unsigned long flags;
	unsigned char *cp;
	int i;
	unsigned int stride, frames, bytes, oldptr;
	int period_elapsed = 0;

	stride = runtime->frame_bits >> 3;

	for (i = 0; i < urb->number_of_packets; i++) {
		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset;
		if (urb->iso_frame_desc[i].status) {
			snd_printd(KERN_ERR "frame %d active: %d\n", i, urb->iso_frame_desc[i].status);
			// continue;
		}
		bytes = urb->iso_frame_desc[i].actual_length;
		frames = bytes / stride;
		if (!subs->txfr_quirk)
			bytes = frames * stride;
		if (bytes % (runtime->sample_bits >> 3) != 0) {
#ifdef CONFIG_SND_DEBUG_VERBOSE
			int oldbytes = bytes;
#endif
			bytes = frames * stride;
			snd_printdd(KERN_ERR "Corrected urb data len. %d->%d\n",
							oldbytes, bytes);
		}
		/* update the current pointer */
		spin_lock_irqsave(&subs->lock, flags);
		oldptr = subs->hwptr_done;
		subs->hwptr_done += bytes;
		if (subs->hwptr_done >= runtime->buffer_size * stride)
			subs->hwptr_done -= runtime->buffer_size * stride;
		frames = (bytes + (oldptr % stride)) / stride;
		subs->transfer_done += frames;
		if (subs->transfer_done >= runtime->period_size) {
			subs->transfer_done -= runtime->period_size;
			period_elapsed = 1;
		}
		spin_unlock_irqrestore(&subs->lock, flags);
		/* copy a data chunk */
		if (oldptr + bytes > runtime->buffer_size * stride) {
			unsigned int bytes1 =
					runtime->buffer_size * stride - oldptr;
			memcpy(runtime->dma_area + oldptr, cp, bytes1);
			memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
		} else {
			memcpy(runtime->dma_area + oldptr, cp, bytes);
		}
	}
	if (period_elapsed)
		snd_pcm_period_elapsed(subs->pcm_substream);
	return 0;
}

/*
 * Process after capture complete when paused.  Nothing to do.
 */
static int retire_paused_capture_urb(struct snd_usb_substream *subs,
				     struct snd_pcm_runtime *runtime,
				     struct urb *urb)
{
	return 0;
}


/*
 * prepare urb for playback sync pipe
 *
 * set up the offset and length to receive the current frequency.
 */
static int prepare_playback_sync_urb(struct snd_usb_substream *subs,
				     struct snd_pcm_runtime *runtime,
				     struct urb *urb)
{
	struct snd_urb_ctx *ctx = urb->context;

	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	urb->iso_frame_desc[0].length = min(4u, ctx->subs->syncmaxsize);
	urb->iso_frame_desc[0].offset = 0;
	return 0;
}

/*
 * process after playback sync complete
 *
 * Full speed devices report feedback values in 10.14 format as samples per
 * frame, high speed devices in 16.16 format as samples per microframe.
 * Because the Audio Class 1 spec was written before USB 2.0, many high speed
 * devices use a wrong interpretation, some others use an entirely different
 * format.  Therefore, we cannot predict what format any particular device uses
 * and must detect it automatically.
 */
static int retire_playback_sync_urb(struct snd_usb_substream *subs,
				    struct snd_pcm_runtime *runtime,
				    struct urb *urb)
{
	unsigned int f;
	int shift;
	unsigned long flags;

	if (urb->iso_frame_desc[0].status != 0 ||
	    urb->iso_frame_desc[0].actual_length < 3)
		return 0;

	f = le32_to_cpup(urb->transfer_buffer);
	if (urb->iso_frame_desc[0].actual_length == 3)
		f &= 0x00ffffff;
	else
		f &= 0x0fffffff;
	if (f == 0)
		return 0;

	if (unlikely(subs->freqshift == INT_MIN)) {
		/*
		 * The first time we see a feedback value, determine its format
		 * by shifting it left or right until it matches the nominal
		 * frequency value.  This assumes that the feedback does not
		 * differ from the nominal value more than +50% or -25%.
		 */
		shift = 0;
		while (f < subs->freqn - subs->freqn / 4) {
			f <<= 1;
			shift++;
		}
		while (f > subs->freqn + subs->freqn / 2) {
			f >>= 1;
			shift--;
		}
		subs->freqshift = shift;
	}
	else if (subs->freqshift >= 0)
		f <<= subs->freqshift;
	else
		f >>= -subs->freqshift;

	if (likely(f >= subs->freqn - subs->freqn / 8 && f <= subs->freqmax)) {
		/*
		 * If the frequency looks valid, set it.
		 * This value is referred to in prepare_playback_urb().
		 */
		spin_lock_irqsave(&subs->lock, flags);
		subs->freqm = f;
		spin_unlock_irqrestore(&subs->lock, flags);
	} else {
		/*
		 * Out of range; maybe the shift value is wrong.
		 * Reset it so that we autodetect again the next time.
		 */
		subs->freqshift = INT_MIN;
	}

	return 0;
}

/* determine the number of frames in the next packet */
static int snd_usb_audio_next_packet_size(struct snd_usb_substream *subs)
{
	if (subs->fill_max)
		return subs->maxframesize;
	else {
		subs->phase = (subs->phase & 0xffff)
			+ (subs->freqm << subs->datainterval);
		return min(subs->phase >> 16, subs->maxframesize);
	}
}

/*
 * Prepare urb for streaming before playback starts or when paused.
 *
 * We don't have any data, so we send silence.
 */
static int prepare_nodata_playback_urb(struct snd_usb_substream *subs,
				       struct snd_pcm_runtime *runtime,
				       struct urb *urb)
{
	unsigned int i, offs, counts;
	struct snd_urb_ctx *ctx = urb->context;
	int stride = runtime->frame_bits >> 3;

	offs = 0;
	urb->dev = ctx->subs->dev;
	for (i = 0; i < ctx->packets; ++i) {
		counts = snd_usb_audio_next_packet_size(subs);
		urb->iso_frame_desc[i].offset = offs * stride;
		urb->iso_frame_desc[i].length = counts * stride;
		offs += counts;
	}
	urb->number_of_packets = ctx->packets;
	urb->transfer_buffer_length = offs * stride;
	memset(urb->transfer_buffer,
	       runtime->format == SNDRV_PCM_FORMAT_U8 ? 0x80 : 0,
	       offs * stride);
	return 0;
}

/*
 * prepare urb for playback data pipe
 *
 * Since a URB can handle only a single linear buffer, we must use double
 * buffering when the data to be transferred overflows the buffer boundary.
 * To avoid inconsistencies when updating hwptr_done, we use double buffering
 * for all URBs.
 */
static int prepare_playback_urb(struct snd_usb_substream *subs,
				struct snd_pcm_runtime *runtime,
				struct urb *urb)
{
	int i, stride;
	unsigned int counts, frames, bytes;
	unsigned long flags;
	int period_elapsed = 0;
	struct snd_urb_ctx *ctx = urb->context;

	stride = runtime->frame_bits >> 3;

	frames = 0;
	urb->dev = ctx->subs->dev; /* we need to set this at each time */
	urb->number_of_packets = 0;
	spin_lock_irqsave(&subs->lock, flags);
	for (i = 0; i < ctx->packets; i++) {
		counts = snd_usb_audio_next_packet_size(subs);
		/* set up descriptor */
		urb->iso_frame_desc[i].offset = frames * stride;
		urb->iso_frame_desc[i].length = counts * stride;
		frames += counts;
		urb->number_of_packets++;
		subs->transfer_done += counts;
		if (subs->transfer_done >= runtime->period_size) {
			subs->transfer_done -= runtime->period_size;
			period_elapsed = 1;
			if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
				if (subs->transfer_done > 0) {
					/* FIXME: fill-max mode is not
					 * supported yet */
					frames -= subs->transfer_done;
					counts -= subs->transfer_done;
					urb->iso_frame_desc[i].length =
						counts * stride;
					subs->transfer_done = 0;
				}
				i++;
				if (i < ctx->packets) {
					/* add a transfer delimiter */
					urb->iso_frame_desc[i].offset =
						frames * stride;
					urb->iso_frame_desc[i].length = 0;
					urb->number_of_packets++;
				}
				break;
			}
		}
		if (period_elapsed) /* finish at the period boundary */
			break;
	}
	bytes = frames * stride;
	if (subs->hwptr_done + bytes > runtime->buffer_size * stride) {
		/* err, the transferred area goes over buffer boundary. */
		unsigned int bytes1 =
			runtime->buffer_size * stride - subs->hwptr_done;
		memcpy(urb->transfer_buffer,
		       runtime->dma_area + subs->hwptr_done, bytes1);
		memcpy(urb->transfer_buffer + bytes1,
		       runtime->dma_area, bytes - bytes1);
	} else {
		memcpy(urb->transfer_buffer,
		       runtime->dma_area + subs->hwptr_done, bytes);
	}
	subs->hwptr_done += bytes;
	if (subs->hwptr_done >= runtime->buffer_size * stride)
		subs->hwptr_done -= runtime->buffer_size * stride;
	runtime->delay += frames;
	spin_unlock_irqrestore(&subs->lock, flags);
	urb->transfer_buffer_length = bytes;
	if (period_elapsed)
		snd_pcm_period_elapsed(subs->pcm_substream);
	return 0;
}

/*
 * process after playback data complete
 * - decrease the delay count again
 */
static int retire_playback_urb(struct snd_usb_substream *subs,
			       struct snd_pcm_runtime *runtime,
			       struct urb *urb)
{
	unsigned long flags;
	int stride = runtime->frame_bits >> 3;
	int processed = urb->transfer_buffer_length / stride;

	spin_lock_irqsave(&subs->lock, flags);
	if (processed > runtime->delay)
		runtime->delay = 0;
	else
		runtime->delay -= processed;
	spin_unlock_irqrestore(&subs->lock, flags);
	return 0;
}

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";
	}
}

/*
 * set up and start data/sync urbs
 */
static int start_urbs(struct snd_usb_substream *subs, struct snd_pcm_runtime *runtime)
{
	unsigned int i;
	int err;

	if (subs->stream->chip->shutdown)
		return -EBADFD;

	for (i = 0; i < subs->nurbs; i++) {
		if (snd_BUG_ON(!subs->dataurb[i].urb))
			return -EINVAL;
		if (subs->ops.prepare(subs, runtime, subs->dataurb[i].urb) < 0) {
			snd_printk(KERN_ERR "cannot prepare datapipe for urb %d\n", i);
			goto __error;
		}
	}
	if (subs->syncpipe) {
		for (i = 0; i < SYNC_URBS; i++) {
			if (snd_BUG_ON(!subs->syncurb[i].urb))
				return -EINVAL;
			if (subs->ops.prepare_sync(subs, runtime, subs->syncurb[i].urb) < 0) {
				snd_printk(KERN_ERR "cannot prepare syncpipe for urb %d\n", i);
				goto __error;
			}
		}
	}

	subs->active_mask = 0;
	subs->unlink_mask = 0;
	subs->running = 1;
	for (i = 0; i < subs->nurbs; i++) {
		err = usb_submit_urb(subs->dataurb[i].urb, GFP_ATOMIC);
		if (err < 0) {
			snd_printk(KERN_ERR "cannot submit datapipe "
				   "for urb %d, error %d: %s\n",
				   i, err, usb_error_string(err));
			goto __error;
		}
		set_bit(i, &subs->active_mask);
	}
	if (subs->syncpipe) {
		for (i = 0; i < SYNC_URBS; i++) {
			err = usb_submit_urb(subs->syncurb[i].urb, GFP_ATOMIC);
			if (err < 0) {
				snd_printk(KERN_ERR "cannot submit syncpipe "
					   "for urb %d, error %d: %s\n",
					   i, err, usb_error_string(err));
				goto __error;
			}
			set_bit(i + 16, &subs->active_mask);
		}
	}
	return 0;

 __error:
	// snd_pcm_stop(subs->pcm_substream, SNDRV_PCM_STATE_XRUN);
	deactivate_urbs(subs, 0, 0);
	return -EPIPE;
}


/*
 */
static struct snd_urb_ops audio_urb_ops[2] = {
	{
		.prepare =	prepare_nodata_playback_urb,
		.retire =	retire_playback_urb,
		.prepare_sync =	prepare_playback_sync_urb,
		.retire_sync =	retire_playback_sync_urb,
	},
	{
		.prepare =	prepare_capture_urb,
		.retire =	retire_capture_urb,
		.prepare_sync =	prepare_capture_sync_urb,
		.retire_sync =	retire_capture_sync_urb,
	},
};

/*
 * initialize the substream instance.
 */

void snd_usb_init_substream(struct snd_usb_stream *as,
			    int stream, struct audioformat *fp)
{
	struct snd_usb_substream *subs = &as->substream[stream];

	INIT_LIST_HEAD(&subs->fmt_list);
	spin_lock_init(&subs->lock);

	subs->stream = as;
	subs->direction = stream;
	subs->dev = as->chip->dev;
	subs->txfr_quirk = as->chip->txfr_quirk;
	subs->ops = audio_urb_ops[stream];
	if (snd_usb_get_speed(subs->dev) >= USB_SPEED_HIGH)
		subs->ops.prepare_sync = prepare_capture_sync_urb_hs;

	snd_usb_set_pcm_ops(as->pcm, stream);

	list_add_tail(&fp->list, &subs->fmt_list);
	subs->formats |= fp->formats;
	subs->endpoint = fp->endpoint;
	subs->num_formats++;
	subs->fmt_type = fp->fmt_type;
}

int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream, int cmd)
{
	struct snd_usb_substream *subs = substream->runtime->private_data;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
		subs->ops.prepare = prepare_playback_urb;
		return 0;
	case SNDRV_PCM_TRIGGER_STOP:
		return deactivate_urbs(subs, 0, 0);
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
		subs->ops.prepare = prepare_nodata_playback_urb;
		return 0;
	}

	return -EINVAL;
}

int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream, int cmd)
{
	struct snd_usb_substream *subs = substream->runtime->private_data;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
		subs->ops.retire = retire_capture_urb;
		return start_urbs(subs, substream->runtime);
	case SNDRV_PCM_TRIGGER_STOP:
		return deactivate_urbs(subs, 0, 0);
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
		subs->ops.retire = retire_paused_capture_urb;
		return 0;
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
		subs->ops.retire = retire_capture_urb;
		return 0;
	}

	return -EINVAL;
}

int snd_usb_substream_prepare(struct snd_usb_substream *subs,
			      struct snd_pcm_runtime *runtime)
{
	/* clear urbs (to be sure) */
	deactivate_urbs(subs, 0, 1);
	wait_clear_urbs(subs);

	/* for playback, submit the URBs now; otherwise, the first hwptr_done
	 * updates for all URBs would happen at the same time when starting */
	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
		subs->ops.prepare = prepare_nodata_playback_urb;
		return start_urbs(subs, runtime);
	}

	return 0;
}