summaryrefslogtreecommitdiffstats
path: root/sound/firewire/oxfw/oxfw-stream.c
blob: e9b6a9f171bfec1b4c741d5102d1543ae0fb4628 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * oxfw_stream.c - a part of driver for OXFW970/971 based devices
 *
 * Copyright (c) 2014 Takashi Sakamoto
 */

#include "oxfw.h"
#include <linux/delay.h>

#define AVC_GENERIC_FRAME_MAXIMUM_BYTES	512
#define CALLBACK_TIMEOUT	200

/*
 * According to datasheet of Oxford Semiconductor:
 *  OXFW970: 32.0/44.1/48.0/96.0 Khz, 8 audio channels I/O
 *  OXFW971: 32.0/44.1/48.0/88.2/96.0/192.0 kHz, 16 audio channels I/O, MIDI I/O
 */
static const unsigned int oxfw_rate_table[] = {
	[0] = 32000,
	[1] = 44100,
	[2] = 48000,
	[3] = 88200,
	[4] = 96000,
	[5] = 192000,
};

/*
 * See Table 5.7 – Sampling frequency for Multi-bit Audio
 * in AV/C Stream Format Information Specification 1.1 (Apr 2005, 1394TA)
 */
static const unsigned int avc_stream_rate_table[] = {
	[0] = 0x02,
	[1] = 0x03,
	[2] = 0x04,
	[3] = 0x0a,
	[4] = 0x05,
	[5] = 0x07,
};

static int set_rate(struct snd_oxfw *oxfw, unsigned int rate)
{
	int err;

	err = avc_general_set_sig_fmt(oxfw->unit, rate,
				      AVC_GENERAL_PLUG_DIR_IN, 0);
	if (err < 0)
		goto end;

	if (oxfw->has_output)
		err = avc_general_set_sig_fmt(oxfw->unit, rate,
					      AVC_GENERAL_PLUG_DIR_OUT, 0);
end:
	return err;
}

static int set_stream_format(struct snd_oxfw *oxfw, struct amdtp_stream *s,
			     unsigned int rate, unsigned int pcm_channels)
{
	u8 **formats;
	struct snd_oxfw_stream_formation formation;
	enum avc_general_plug_dir dir;
	unsigned int len;
	int i, err;

	if (s == &oxfw->tx_stream) {
		formats = oxfw->tx_stream_formats;
		dir = AVC_GENERAL_PLUG_DIR_OUT;
	} else {
		formats = oxfw->rx_stream_formats;
		dir = AVC_GENERAL_PLUG_DIR_IN;
	}

	/* Seek stream format for requirements. */
	for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) {
		err = snd_oxfw_stream_parse_format(formats[i], &formation);
		if (err < 0)
			return err;

		if ((formation.rate == rate) && (formation.pcm == pcm_channels))
			break;
	}
	if (i == SND_OXFW_STREAM_FORMAT_ENTRIES)
		return -EINVAL;

	/* If assumed, just change rate. */
	if (oxfw->assumed)
		return set_rate(oxfw, rate);

	/* Calculate format length. */
	len = 5 + formats[i][4] * 2;

	err = avc_stream_set_format(oxfw->unit, dir, 0, formats[i], len);
	if (err < 0)
		return err;

	/* Some requests just after changing format causes freezing. */
	msleep(100);

	return 0;
}

static int start_stream(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
{
	struct cmp_connection *conn;
	int err;

	if (stream == &oxfw->rx_stream)
		conn = &oxfw->in_conn;
	else
		conn = &oxfw->out_conn;

	err = cmp_connection_establish(conn);
	if (err < 0)
		return err;

	err = amdtp_domain_add_stream(&oxfw->domain, stream,
				      conn->resources.channel, conn->speed);
	if (err < 0) {
		cmp_connection_break(conn);
		return err;
	}

	return 0;
}

static int check_connection_used_by_others(struct snd_oxfw *oxfw,
					   struct amdtp_stream *stream)
{
	struct cmp_connection *conn;
	bool used;
	int err;

	if (stream == &oxfw->tx_stream)
		conn = &oxfw->out_conn;
	else
		conn = &oxfw->in_conn;

	err = cmp_connection_check_used(conn, &used);
	if ((err >= 0) && used && !amdtp_stream_running(stream)) {
		dev_err(&oxfw->unit->device,
			"Connection established by others: %cPCR[%d]\n",
			(conn->direction == CMP_OUTPUT) ? 'o' : 'i',
			conn->pcr_index);
		err = -EBUSY;
	}

	return err;
}

static int init_stream(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
{
	struct cmp_connection *conn;
	enum cmp_direction c_dir;
	enum amdtp_stream_direction s_dir;
	unsigned int flags;
	int err;

	if (!(oxfw->quirks & SND_OXFW_QUIRK_BLOCKING_TRANSMISSION))
		flags = CIP_NONBLOCKING;
	else
		flags = CIP_BLOCKING;

	if (stream == &oxfw->tx_stream) {
		conn = &oxfw->out_conn;
		c_dir = CMP_OUTPUT;
		s_dir = AMDTP_IN_STREAM;

		if (oxfw->quirks & SND_OXFW_QUIRK_JUMBO_PAYLOAD)
			flags |= CIP_JUMBO_PAYLOAD;
		if (oxfw->quirks & SND_OXFW_QUIRK_WRONG_DBS)
			flags |= CIP_WRONG_DBS;
	} else {
		conn = &oxfw->in_conn;
		c_dir = CMP_INPUT;
		s_dir = AMDTP_OUT_STREAM;
	}

	err = cmp_connection_init(conn, oxfw->unit, c_dir, 0);
	if (err < 0)
		return err;

	err = amdtp_am824_init(stream, oxfw->unit, s_dir, flags);
	if (err < 0) {
		cmp_connection_destroy(conn);
		return err;
	}

	return 0;
}

static int keep_resources(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
{
	enum avc_general_plug_dir dir;
	u8 **formats;
	struct snd_oxfw_stream_formation formation;
	struct cmp_connection *conn;
	int i;
	int err;

	if (stream == &oxfw->rx_stream) {
		dir = AVC_GENERAL_PLUG_DIR_IN;
		formats = oxfw->rx_stream_formats;
		conn = &oxfw->in_conn;
	} else {
		dir = AVC_GENERAL_PLUG_DIR_OUT;
		formats = oxfw->tx_stream_formats;
		conn = &oxfw->out_conn;
	}

	err = snd_oxfw_stream_get_current_formation(oxfw, dir, &formation);
	if (err < 0)
		return err;

	for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) {
		struct snd_oxfw_stream_formation fmt;

		if (formats[i] == NULL)
			break;

		err = snd_oxfw_stream_parse_format(formats[i], &fmt);
		if (err < 0)
			return err;

		if (fmt.rate == formation.rate && fmt.pcm == formation.pcm &&
		    fmt.midi == formation.midi)
			break;
	}
	if (i == SND_OXFW_STREAM_FORMAT_ENTRIES)
		return -EINVAL;

	// The stream should have one pcm channels at least.
	if (formation.pcm == 0)
		return -EINVAL;

	err = amdtp_am824_set_parameters(stream, formation.rate, formation.pcm,
					 formation.midi * 8, false);
	if (err < 0)
		return err;

	return cmp_connection_reserve(conn, amdtp_stream_get_max_payload(stream));
}

int snd_oxfw_stream_reserve_duplex(struct snd_oxfw *oxfw,
				   struct amdtp_stream *stream,
				   unsigned int rate, unsigned int pcm_channels,
				   unsigned int frames_per_period,
				   unsigned int frames_per_buffer)
{
	struct snd_oxfw_stream_formation formation;
	enum avc_general_plug_dir dir;
	int err;

	// Considering JACK/FFADO streaming:
	// TODO: This can be removed hwdep functionality becomes popular.
	err = check_connection_used_by_others(oxfw, &oxfw->rx_stream);
	if (err < 0)
		return err;
	if (oxfw->has_output) {
		err = check_connection_used_by_others(oxfw, &oxfw->tx_stream);
		if (err < 0)
			return err;
	}

	if (stream == &oxfw->tx_stream)
		dir = AVC_GENERAL_PLUG_DIR_OUT;
	else
		dir = AVC_GENERAL_PLUG_DIR_IN;

	err = snd_oxfw_stream_get_current_formation(oxfw, dir, &formation);
	if (err < 0)
		return err;
	if (rate == 0) {
		rate = formation.rate;
		pcm_channels = formation.pcm;
	}
	if (formation.rate != rate || formation.pcm != pcm_channels) {
		amdtp_domain_stop(&oxfw->domain);

		cmp_connection_break(&oxfw->in_conn);
		cmp_connection_release(&oxfw->in_conn);

		if (oxfw->has_output) {
			cmp_connection_break(&oxfw->out_conn);
			cmp_connection_release(&oxfw->out_conn);
		}
	}

	if (oxfw->substreams_count == 0 ||
	    formation.rate != rate || formation.pcm != pcm_channels) {
		err = set_stream_format(oxfw, stream, rate, pcm_channels);
		if (err < 0) {
			dev_err(&oxfw->unit->device,
				"fail to set stream format: %d\n", err);
			return err;
		}

		err = keep_resources(oxfw, &oxfw->rx_stream);
		if (err < 0)
			return err;

		if (oxfw->has_output) {
			err = keep_resources(oxfw, &oxfw->tx_stream);
			if (err < 0) {
				cmp_connection_release(&oxfw->in_conn);
				return err;
			}
		}

		err = amdtp_domain_set_events_per_period(&oxfw->domain,
					frames_per_period, frames_per_buffer);
		if (err < 0) {
			cmp_connection_release(&oxfw->in_conn);
			if (oxfw->has_output)
				cmp_connection_release(&oxfw->out_conn);
			return err;
		}
	}

	return 0;
}

int snd_oxfw_stream_start_duplex(struct snd_oxfw *oxfw)
{
	int err;

	if (oxfw->substreams_count == 0)
		return -EIO;

	if (amdtp_streaming_error(&oxfw->rx_stream) ||
	    amdtp_streaming_error(&oxfw->tx_stream)) {
		amdtp_domain_stop(&oxfw->domain);

		cmp_connection_break(&oxfw->in_conn);
		if (oxfw->has_output)
			cmp_connection_break(&oxfw->out_conn);
	}

	if (!amdtp_stream_running(&oxfw->rx_stream)) {
		err = start_stream(oxfw, &oxfw->rx_stream);
		if (err < 0) {
			dev_err(&oxfw->unit->device,
				"fail to prepare rx stream: %d\n", err);
			goto error;
		}

		if (oxfw->has_output &&
		    !amdtp_stream_running(&oxfw->tx_stream)) {
			err = start_stream(oxfw, &oxfw->tx_stream);
			if (err < 0) {
				dev_err(&oxfw->unit->device,
					"fail to prepare tx stream: %d\n", err);
				goto error;
			}
		}

		err = amdtp_domain_start(&oxfw->domain, 0);
		if (err < 0)
			goto error;

		// Wait first packet.
		if (!amdtp_stream_wait_callback(&oxfw->rx_stream,
						CALLBACK_TIMEOUT)) {
			err = -ETIMEDOUT;
			goto error;
		}

		if (oxfw->has_output) {
			if (!amdtp_stream_wait_callback(&oxfw->tx_stream,
							CALLBACK_TIMEOUT)) {
				err = -ETIMEDOUT;
				goto error;
			}
		}
	}

	return 0;
error:
	amdtp_domain_stop(&oxfw->domain);

	cmp_connection_break(&oxfw->in_conn);
	if (oxfw->has_output)
		cmp_connection_break(&oxfw->out_conn);

	return err;
}

void snd_oxfw_stream_stop_duplex(struct snd_oxfw *oxfw)
{
	if (oxfw->substreams_count == 0) {
		amdtp_domain_stop(&oxfw->domain);

		cmp_connection_break(&oxfw->in_conn);
		cmp_connection_release(&oxfw->in_conn);

		if (oxfw->has_output) {
			cmp_connection_break(&oxfw->out_conn);
			cmp_connection_release(&oxfw->out_conn);
		}
	}
}

static void destroy_stream(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
{
	struct cmp_connection *conn;

	if (stream == &oxfw->tx_stream)
		conn = &oxfw->out_conn;
	else
		conn = &oxfw->in_conn;

	amdtp_stream_destroy(stream);
	cmp_connection_destroy(conn);
}

int snd_oxfw_stream_init_duplex(struct snd_oxfw *oxfw)
{
	int err;

	err = init_stream(oxfw, &oxfw->rx_stream);
	if (err < 0)
		return err;

	if (oxfw->has_output) {
		err = init_stream(oxfw, &oxfw->tx_stream);
		if (err < 0) {
			destroy_stream(oxfw, &oxfw->rx_stream);
			return err;
		}
	}

	err = amdtp_domain_init(&oxfw->domain);
	if (err < 0) {
		destroy_stream(oxfw, &oxfw->rx_stream);
		if (oxfw->has_output)
			destroy_stream(oxfw, &oxfw->tx_stream);
	}

	return err;
}

// This function should be called before starting the stream or after stopping
// the streams.
void snd_oxfw_stream_destroy_duplex(struct snd_oxfw *oxfw)
{
	amdtp_domain_destroy(&oxfw->domain);

	destroy_stream(oxfw, &oxfw->rx_stream);

	if (oxfw->has_output)
		destroy_stream(oxfw, &oxfw->tx_stream);
}

void snd_oxfw_stream_update_duplex(struct snd_oxfw *oxfw)
{
	amdtp_domain_stop(&oxfw->domain);

	cmp_connection_break(&oxfw->in_conn);

	amdtp_stream_pcm_abort(&oxfw->rx_stream);

	if (oxfw->has_output) {
		cmp_connection_break(&oxfw->out_conn);

		amdtp_stream_pcm_abort(&oxfw->tx_stream);
	}
}

int snd_oxfw_stream_get_current_formation(struct snd_oxfw *oxfw,
				enum avc_general_plug_dir dir,
				struct snd_oxfw_stream_formation *formation)
{
	u8 *format;
	unsigned int len;
	int err;

	len = AVC_GENERIC_FRAME_MAXIMUM_BYTES;
	format = kmalloc(len, GFP_KERNEL);
	if (format == NULL)
		return -ENOMEM;

	err = avc_stream_get_format_single(oxfw->unit, dir, 0, format, &len);
	if (err < 0)
		goto end;
	if (len < 3) {
		err = -EIO;
		goto end;
	}

	err = snd_oxfw_stream_parse_format(format, formation);
end:
	kfree(format);
	return err;
}

/*
 * See Table 6.16 - AM824 Stream Format
 *     Figure 6.19 - format_information field for AM824 Compound
 * in AV/C Stream Format Information Specification 1.1 (Apr 2005, 1394TA)
 * Also 'Clause 12 AM824 sequence adaption layers' in IEC 61883-6:2005
 */
int snd_oxfw_stream_parse_format(u8 *format,
				 struct snd_oxfw_stream_formation *formation)
{
	unsigned int i, e, channels, type;

	memset(formation, 0, sizeof(struct snd_oxfw_stream_formation));

	/*
	 * this module can support a hierarchy combination that:
	 *  Root:	Audio and Music (0x90)
	 *  Level 1:	AM824 Compound  (0x40)
	 */
	if ((format[0] != 0x90) || (format[1] != 0x40))
		return -ENXIO;

	/* check the sampling rate */
	for (i = 0; i < ARRAY_SIZE(avc_stream_rate_table); i++) {
		if (format[2] == avc_stream_rate_table[i])
			break;
	}
	if (i == ARRAY_SIZE(avc_stream_rate_table))
		return -ENXIO;

	formation->rate = oxfw_rate_table[i];

	for (e = 0; e < format[4]; e++) {
		channels = format[5 + e * 2];
		type = format[6 + e * 2];

		switch (type) {
		/* IEC 60958 Conformant, currently handled as MBLA */
		case 0x00:
		/* Multi Bit Linear Audio (Raw) */
		case 0x06:
			formation->pcm += channels;
			break;
		/* MIDI Conformant */
		case 0x0d:
			formation->midi = channels;
			break;
		/* IEC 61937-3 to 7 */
		case 0x01:
		case 0x02:
		case 0x03:
		case 0x04:
		case 0x05:
		/* Multi Bit Linear Audio */
		case 0x07:	/* DVD-Audio */
		case 0x0c:	/* High Precision */
		/* One Bit Audio */
		case 0x08:	/* (Plain) Raw */
		case 0x09:	/* (Plain) SACD */
		case 0x0a:	/* (Encoded) Raw */
		case 0x0b:	/* (Encoded) SACD */
		/* SMPTE Time-Code conformant */
		case 0x0e:
		/* Sample Count */
		case 0x0f:
		/* Anciliary Data */
		case 0x10:
		/* Synchronization Stream (Stereo Raw audio) */
		case 0x40:
		/* Don't care */
		case 0xff:
		default:
			return -ENXIO;	/* not supported */
		}
	}

	if (formation->pcm  > AM824_MAX_CHANNELS_FOR_PCM ||
	    formation->midi > AM824_MAX_CHANNELS_FOR_MIDI)
		return -ENXIO;

	return 0;
}

static int
assume_stream_formats(struct snd_oxfw *oxfw, enum avc_general_plug_dir dir,
		      unsigned int pid, u8 *buf, unsigned int *len,
		      u8 **formats)
{
	struct snd_oxfw_stream_formation formation;
	unsigned int i, eid;
	int err;

	/* get format at current sampling rate */
	err = avc_stream_get_format_single(oxfw->unit, dir, pid, buf, len);
	if (err < 0) {
		dev_err(&oxfw->unit->device,
		"fail to get current stream format for isoc %s plug %d:%d\n",
			(dir == AVC_GENERAL_PLUG_DIR_IN) ? "in" : "out",
			pid, err);
		goto end;
	}

	/* parse and set stream format */
	eid = 0;
	err = snd_oxfw_stream_parse_format(buf, &formation);
	if (err < 0)
		goto end;

	formats[eid] = devm_kmemdup(&oxfw->card->card_dev, buf, *len,
				    GFP_KERNEL);
	if (!formats[eid]) {
		err = -ENOMEM;
		goto end;
	}

	/* apply the format for each available sampling rate */
	for (i = 0; i < ARRAY_SIZE(oxfw_rate_table); i++) {
		if (formation.rate == oxfw_rate_table[i])
			continue;

		err = avc_general_inquiry_sig_fmt(oxfw->unit,
						  oxfw_rate_table[i],
						  dir, pid);
		if (err < 0)
			continue;

		eid++;
		formats[eid] = devm_kmemdup(&oxfw->card->card_dev, buf, *len,
					    GFP_KERNEL);
		if (formats[eid] == NULL) {
			err = -ENOMEM;
			goto end;
		}
		formats[eid][2] = avc_stream_rate_table[i];
	}

	err = 0;
	oxfw->assumed = true;
end:
	return err;
}

static int fill_stream_formats(struct snd_oxfw *oxfw,
			       enum avc_general_plug_dir dir,
			       unsigned short pid)
{
	u8 *buf, **formats;
	unsigned int len, eid = 0;
	struct snd_oxfw_stream_formation dummy;
	int err;

	buf = kmalloc(AVC_GENERIC_FRAME_MAXIMUM_BYTES, GFP_KERNEL);
	if (buf == NULL)
		return -ENOMEM;

	if (dir == AVC_GENERAL_PLUG_DIR_OUT)
		formats = oxfw->tx_stream_formats;
	else
		formats = oxfw->rx_stream_formats;

	/* get first entry */
	len = AVC_GENERIC_FRAME_MAXIMUM_BYTES;
	err = avc_stream_get_format_list(oxfw->unit, dir, 0, buf, &len, 0);
	if (err == -ENXIO) {
		/* LIST subfunction is not implemented */
		len = AVC_GENERIC_FRAME_MAXIMUM_BYTES;
		err = assume_stream_formats(oxfw, dir, pid, buf, &len,
					    formats);
		goto end;
	} else if (err < 0) {
		dev_err(&oxfw->unit->device,
			"fail to get stream format %d for isoc %s plug %d:%d\n",
			eid, (dir == AVC_GENERAL_PLUG_DIR_IN) ? "in" : "out",
			pid, err);
		goto end;
	}

	/* LIST subfunction is implemented */
	while (eid < SND_OXFW_STREAM_FORMAT_ENTRIES) {
		/* The format is too short. */
		if (len < 3) {
			err = -EIO;
			break;
		}

		/* parse and set stream format */
		err = snd_oxfw_stream_parse_format(buf, &dummy);
		if (err < 0)
			break;

		formats[eid] = devm_kmemdup(&oxfw->card->card_dev, buf, len,
					    GFP_KERNEL);
		if (!formats[eid]) {
			err = -ENOMEM;
			break;
		}

		/* get next entry */
		len = AVC_GENERIC_FRAME_MAXIMUM_BYTES;
		err = avc_stream_get_format_list(oxfw->unit, dir, 0,
						 buf, &len, ++eid);
		/* No entries remained. */
		if (err == -EINVAL) {
			err = 0;
			break;
		} else if (err < 0) {
			dev_err(&oxfw->unit->device,
			"fail to get stream format %d for isoc %s plug %d:%d\n",
				eid, (dir == AVC_GENERAL_PLUG_DIR_IN) ? "in" :
									"out",
				pid, err);
			break;
		}
	}
end:
	kfree(buf);
	return err;
}

int snd_oxfw_stream_discover(struct snd_oxfw *oxfw)
{
	u8 plugs[AVC_PLUG_INFO_BUF_BYTES];
	struct snd_oxfw_stream_formation formation;
	u8 *format;
	unsigned int i;
	int err;

	/* the number of plugs for isoc in/out, ext in/out  */
	err = avc_general_get_plug_info(oxfw->unit, 0x1f, 0x07, 0x00, plugs);
	if (err < 0) {
		dev_err(&oxfw->unit->device,
		"fail to get info for isoc/external in/out plugs: %d\n",
			err);
		goto end;
	} else if ((plugs[0] == 0) && (plugs[1] == 0)) {
		err = -ENXIO;
		goto end;
	}

	/* use oPCR[0] if exists */
	if (plugs[1] > 0) {
		err = fill_stream_formats(oxfw, AVC_GENERAL_PLUG_DIR_OUT, 0);
		if (err < 0) {
			if (err != -ENXIO)
				return err;

			// The oPCR is not available for isoc communication.
			err = 0;
		} else {
			for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) {
				format = oxfw->tx_stream_formats[i];
				if (format == NULL)
					continue;
				err = snd_oxfw_stream_parse_format(format,
								   &formation);
				if (err < 0)
					continue;

				/* Add one MIDI port. */
				if (formation.midi > 0)
					oxfw->midi_input_ports = 1;
			}

			oxfw->has_output = true;
		}
	}

	/* use iPCR[0] if exists */
	if (plugs[0] > 0) {
		err = fill_stream_formats(oxfw, AVC_GENERAL_PLUG_DIR_IN, 0);
		if (err < 0) {
			if (err != -ENXIO)
				return err;

			// The iPCR is not available for isoc communication.
			err = 0;
		} else {
			for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) {
				format = oxfw->rx_stream_formats[i];
				if (format == NULL)
					continue;
				err = snd_oxfw_stream_parse_format(format,
								   &formation);
				if (err < 0)
					continue;

				/* Add one MIDI port. */
				if (formation.midi > 0)
					oxfw->midi_output_ports = 1;
			}

			oxfw->has_input = true;
		}
	}
end:
	return err;
}

void snd_oxfw_stream_lock_changed(struct snd_oxfw *oxfw)
{
	oxfw->dev_lock_changed = true;
	wake_up(&oxfw->hwdep_wait);
}

int snd_oxfw_stream_lock_try(struct snd_oxfw *oxfw)
{
	int err;

	spin_lock_irq(&oxfw->lock);

	/* user land lock this */
	if (oxfw->dev_lock_count < 0) {
		err = -EBUSY;
		goto end;
	}

	/* this is the first time */
	if (oxfw->dev_lock_count++ == 0)
		snd_oxfw_stream_lock_changed(oxfw);
	err = 0;
end:
	spin_unlock_irq(&oxfw->lock);
	return err;
}

void snd_oxfw_stream_lock_release(struct snd_oxfw *oxfw)
{
	spin_lock_irq(&oxfw->lock);

	if (WARN_ON(oxfw->dev_lock_count <= 0))
		goto end;
	if (--oxfw->dev_lock_count == 0)
		snd_oxfw_stream_lock_changed(oxfw);
end:
	spin_unlock_irq(&oxfw->lock);
}