xref: /linux/sound/firewire/oxfw/oxfw-stream.c (revision 6fdcba32711044c35c0e1b094cbd8f3f0b4472c9)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * oxfw_stream.c - a part of driver for OXFW970/971 based devices
4  *
5  * Copyright (c) 2014 Takashi Sakamoto
6  */
7 
8 #include "oxfw.h"
9 #include <linux/delay.h>
10 
11 #define AVC_GENERIC_FRAME_MAXIMUM_BYTES	512
12 #define CALLBACK_TIMEOUT	200
13 
14 /*
15  * According to datasheet of Oxford Semiconductor:
16  *  OXFW970: 32.0/44.1/48.0/96.0 Khz, 8 audio channels I/O
17  *  OXFW971: 32.0/44.1/48.0/88.2/96.0/192.0 kHz, 16 audio channels I/O, MIDI I/O
18  */
19 static const unsigned int oxfw_rate_table[] = {
20 	[0] = 32000,
21 	[1] = 44100,
22 	[2] = 48000,
23 	[3] = 88200,
24 	[4] = 96000,
25 	[5] = 192000,
26 };
27 
28 /*
29  * See Table 5.7 – Sampling frequency for Multi-bit Audio
30  * in AV/C Stream Format Information Specification 1.1 (Apr 2005, 1394TA)
31  */
32 static const unsigned int avc_stream_rate_table[] = {
33 	[0] = 0x02,
34 	[1] = 0x03,
35 	[2] = 0x04,
36 	[3] = 0x0a,
37 	[4] = 0x05,
38 	[5] = 0x07,
39 };
40 
41 static int set_rate(struct snd_oxfw *oxfw, unsigned int rate)
42 {
43 	int err;
44 
45 	err = avc_general_set_sig_fmt(oxfw->unit, rate,
46 				      AVC_GENERAL_PLUG_DIR_IN, 0);
47 	if (err < 0)
48 		goto end;
49 
50 	if (oxfw->has_output)
51 		err = avc_general_set_sig_fmt(oxfw->unit, rate,
52 					      AVC_GENERAL_PLUG_DIR_OUT, 0);
53 end:
54 	return err;
55 }
56 
57 static int set_stream_format(struct snd_oxfw *oxfw, struct amdtp_stream *s,
58 			     unsigned int rate, unsigned int pcm_channels)
59 {
60 	u8 **formats;
61 	struct snd_oxfw_stream_formation formation;
62 	enum avc_general_plug_dir dir;
63 	unsigned int len;
64 	int i, err;
65 
66 	if (s == &oxfw->tx_stream) {
67 		formats = oxfw->tx_stream_formats;
68 		dir = AVC_GENERAL_PLUG_DIR_OUT;
69 	} else {
70 		formats = oxfw->rx_stream_formats;
71 		dir = AVC_GENERAL_PLUG_DIR_IN;
72 	}
73 
74 	/* Seek stream format for requirements. */
75 	for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) {
76 		err = snd_oxfw_stream_parse_format(formats[i], &formation);
77 		if (err < 0)
78 			return err;
79 
80 		if ((formation.rate == rate) && (formation.pcm == pcm_channels))
81 			break;
82 	}
83 	if (i == SND_OXFW_STREAM_FORMAT_ENTRIES)
84 		return -EINVAL;
85 
86 	/* If assumed, just change rate. */
87 	if (oxfw->assumed)
88 		return set_rate(oxfw, rate);
89 
90 	/* Calculate format length. */
91 	len = 5 + formats[i][4] * 2;
92 
93 	err = avc_stream_set_format(oxfw->unit, dir, 0, formats[i], len);
94 	if (err < 0)
95 		return err;
96 
97 	/* Some requests just after changing format causes freezing. */
98 	msleep(100);
99 
100 	return 0;
101 }
102 
103 static int start_stream(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
104 {
105 	struct cmp_connection *conn;
106 	int err;
107 
108 	if (stream == &oxfw->rx_stream)
109 		conn = &oxfw->in_conn;
110 	else
111 		conn = &oxfw->out_conn;
112 
113 	err = cmp_connection_establish(conn);
114 	if (err < 0)
115 		return err;
116 
117 	err = amdtp_domain_add_stream(&oxfw->domain, stream,
118 				      conn->resources.channel, conn->speed);
119 	if (err < 0) {
120 		cmp_connection_break(conn);
121 		return err;
122 	}
123 
124 	return 0;
125 }
126 
127 static int check_connection_used_by_others(struct snd_oxfw *oxfw,
128 					   struct amdtp_stream *stream)
129 {
130 	struct cmp_connection *conn;
131 	bool used;
132 	int err;
133 
134 	if (stream == &oxfw->tx_stream)
135 		conn = &oxfw->out_conn;
136 	else
137 		conn = &oxfw->in_conn;
138 
139 	err = cmp_connection_check_used(conn, &used);
140 	if ((err >= 0) && used && !amdtp_stream_running(stream)) {
141 		dev_err(&oxfw->unit->device,
142 			"Connection established by others: %cPCR[%d]\n",
143 			(conn->direction == CMP_OUTPUT) ? 'o' : 'i',
144 			conn->pcr_index);
145 		err = -EBUSY;
146 	}
147 
148 	return err;
149 }
150 
151 static int init_stream(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
152 {
153 	struct cmp_connection *conn;
154 	enum cmp_direction c_dir;
155 	enum amdtp_stream_direction s_dir;
156 	int err;
157 
158 	if (stream == &oxfw->tx_stream) {
159 		conn = &oxfw->out_conn;
160 		c_dir = CMP_OUTPUT;
161 		s_dir = AMDTP_IN_STREAM;
162 	} else {
163 		conn = &oxfw->in_conn;
164 		c_dir = CMP_INPUT;
165 		s_dir = AMDTP_OUT_STREAM;
166 	}
167 
168 	err = cmp_connection_init(conn, oxfw->unit, c_dir, 0);
169 	if (err < 0)
170 		return err;
171 
172 	err = amdtp_am824_init(stream, oxfw->unit, s_dir, CIP_NONBLOCKING);
173 	if (err < 0) {
174 		cmp_connection_destroy(conn);
175 		return err;
176 	}
177 
178 	/*
179 	 * OXFW starts to transmit packets with non-zero dbc.
180 	 * OXFW postpone transferring packets till handling any asynchronous
181 	 * packets. As a result, next isochronous packet includes more data
182 	 * blocks than IEC 61883-6 defines.
183 	 */
184 	if (stream == &oxfw->tx_stream) {
185 		oxfw->tx_stream.flags |= CIP_JUMBO_PAYLOAD;
186 		if (oxfw->wrong_dbs)
187 			oxfw->tx_stream.flags |= CIP_WRONG_DBS;
188 	}
189 
190 	return 0;
191 }
192 
193 static int keep_resources(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
194 {
195 	enum avc_general_plug_dir dir;
196 	u8 **formats;
197 	struct snd_oxfw_stream_formation formation;
198 	struct cmp_connection *conn;
199 	int i;
200 	int err;
201 
202 	if (stream == &oxfw->rx_stream) {
203 		dir = AVC_GENERAL_PLUG_DIR_IN;
204 		formats = oxfw->rx_stream_formats;
205 		conn = &oxfw->in_conn;
206 	} else {
207 		dir = AVC_GENERAL_PLUG_DIR_OUT;
208 		formats = oxfw->tx_stream_formats;
209 		conn = &oxfw->out_conn;
210 	}
211 
212 	err = snd_oxfw_stream_get_current_formation(oxfw, dir, &formation);
213 	if (err < 0)
214 		return err;
215 
216 	for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) {
217 		struct snd_oxfw_stream_formation fmt;
218 
219 		if (formats[i] == NULL)
220 			break;
221 
222 		err = snd_oxfw_stream_parse_format(formats[i], &fmt);
223 		if (err < 0)
224 			return err;
225 
226 		if (fmt.rate == formation.rate && fmt.pcm == formation.pcm &&
227 		    fmt.midi == formation.midi)
228 			break;
229 	}
230 	if (i == SND_OXFW_STREAM_FORMAT_ENTRIES)
231 		return -EINVAL;
232 
233 	// The stream should have one pcm channels at least.
234 	if (formation.pcm == 0)
235 		return -EINVAL;
236 
237 	err = amdtp_am824_set_parameters(stream, formation.rate, formation.pcm,
238 					 formation.midi * 8, false);
239 	if (err < 0)
240 		return err;
241 
242 	return cmp_connection_reserve(conn, amdtp_stream_get_max_payload(stream));
243 }
244 
245 int snd_oxfw_stream_reserve_duplex(struct snd_oxfw *oxfw,
246 				   struct amdtp_stream *stream,
247 				   unsigned int rate, unsigned int pcm_channels,
248 				   unsigned int frames_per_period,
249 				   unsigned int frames_per_buffer)
250 {
251 	struct snd_oxfw_stream_formation formation;
252 	enum avc_general_plug_dir dir;
253 	int err;
254 
255 	// Considering JACK/FFADO streaming:
256 	// TODO: This can be removed hwdep functionality becomes popular.
257 	err = check_connection_used_by_others(oxfw, &oxfw->rx_stream);
258 	if (err < 0)
259 		return err;
260 	if (oxfw->has_output) {
261 		err = check_connection_used_by_others(oxfw, &oxfw->tx_stream);
262 		if (err < 0)
263 			return err;
264 	}
265 
266 	if (stream == &oxfw->tx_stream)
267 		dir = AVC_GENERAL_PLUG_DIR_OUT;
268 	else
269 		dir = AVC_GENERAL_PLUG_DIR_IN;
270 
271 	err = snd_oxfw_stream_get_current_formation(oxfw, dir, &formation);
272 	if (err < 0)
273 		return err;
274 	if (rate == 0) {
275 		rate = formation.rate;
276 		pcm_channels = formation.pcm;
277 	}
278 	if (formation.rate != rate || formation.pcm != pcm_channels) {
279 		amdtp_domain_stop(&oxfw->domain);
280 
281 		cmp_connection_break(&oxfw->in_conn);
282 		cmp_connection_release(&oxfw->in_conn);
283 
284 		if (oxfw->has_output) {
285 			cmp_connection_break(&oxfw->out_conn);
286 			cmp_connection_release(&oxfw->out_conn);
287 		}
288 	}
289 
290 	if (oxfw->substreams_count == 0 ||
291 	    formation.rate != rate || formation.pcm != pcm_channels) {
292 		err = set_stream_format(oxfw, stream, rate, pcm_channels);
293 		if (err < 0) {
294 			dev_err(&oxfw->unit->device,
295 				"fail to set stream format: %d\n", err);
296 			return err;
297 		}
298 
299 		err = keep_resources(oxfw, &oxfw->rx_stream);
300 		if (err < 0)
301 			return err;
302 
303 		if (oxfw->has_output) {
304 			err = keep_resources(oxfw, &oxfw->tx_stream);
305 			if (err < 0) {
306 				cmp_connection_release(&oxfw->in_conn);
307 				return err;
308 			}
309 		}
310 
311 		err = amdtp_domain_set_events_per_period(&oxfw->domain,
312 					frames_per_period, frames_per_buffer);
313 		if (err < 0) {
314 			cmp_connection_release(&oxfw->in_conn);
315 			if (oxfw->has_output)
316 				cmp_connection_release(&oxfw->out_conn);
317 			return err;
318 		}
319 	}
320 
321 	return 0;
322 }
323 
324 int snd_oxfw_stream_start_duplex(struct snd_oxfw *oxfw)
325 {
326 	int err;
327 
328 	if (oxfw->substreams_count == 0)
329 		return -EIO;
330 
331 	if (amdtp_streaming_error(&oxfw->rx_stream) ||
332 	    amdtp_streaming_error(&oxfw->tx_stream)) {
333 		amdtp_domain_stop(&oxfw->domain);
334 
335 		cmp_connection_break(&oxfw->in_conn);
336 		if (oxfw->has_output)
337 			cmp_connection_break(&oxfw->out_conn);
338 	}
339 
340 	if (!amdtp_stream_running(&oxfw->rx_stream)) {
341 		err = start_stream(oxfw, &oxfw->rx_stream);
342 		if (err < 0) {
343 			dev_err(&oxfw->unit->device,
344 				"fail to prepare rx stream: %d\n", err);
345 			goto error;
346 		}
347 
348 		if (oxfw->has_output &&
349 		    !amdtp_stream_running(&oxfw->tx_stream)) {
350 			err = start_stream(oxfw, &oxfw->tx_stream);
351 			if (err < 0) {
352 				dev_err(&oxfw->unit->device,
353 					"fail to prepare tx stream: %d\n", err);
354 				goto error;
355 			}
356 		}
357 
358 		err = amdtp_domain_start(&oxfw->domain, 0);
359 		if (err < 0)
360 			goto error;
361 
362 		// Wait first packet.
363 		if (!amdtp_stream_wait_callback(&oxfw->rx_stream,
364 						CALLBACK_TIMEOUT)) {
365 			err = -ETIMEDOUT;
366 			goto error;
367 		}
368 
369 		if (oxfw->has_output) {
370 			if (!amdtp_stream_wait_callback(&oxfw->tx_stream,
371 							CALLBACK_TIMEOUT)) {
372 				err = -ETIMEDOUT;
373 				goto error;
374 			}
375 		}
376 	}
377 
378 	return 0;
379 error:
380 	amdtp_domain_stop(&oxfw->domain);
381 
382 	cmp_connection_break(&oxfw->in_conn);
383 	if (oxfw->has_output)
384 		cmp_connection_break(&oxfw->out_conn);
385 
386 	return err;
387 }
388 
389 void snd_oxfw_stream_stop_duplex(struct snd_oxfw *oxfw)
390 {
391 	if (oxfw->substreams_count == 0) {
392 		amdtp_domain_stop(&oxfw->domain);
393 
394 		cmp_connection_break(&oxfw->in_conn);
395 		cmp_connection_release(&oxfw->in_conn);
396 
397 		if (oxfw->has_output) {
398 			cmp_connection_break(&oxfw->out_conn);
399 			cmp_connection_release(&oxfw->out_conn);
400 		}
401 	}
402 }
403 
404 static void destroy_stream(struct snd_oxfw *oxfw, struct amdtp_stream *stream)
405 {
406 	struct cmp_connection *conn;
407 
408 	if (stream == &oxfw->tx_stream)
409 		conn = &oxfw->out_conn;
410 	else
411 		conn = &oxfw->in_conn;
412 
413 	amdtp_stream_destroy(stream);
414 	cmp_connection_destroy(conn);
415 }
416 
417 int snd_oxfw_stream_init_duplex(struct snd_oxfw *oxfw)
418 {
419 	int err;
420 
421 	err = init_stream(oxfw, &oxfw->rx_stream);
422 	if (err < 0)
423 		return err;
424 
425 	if (oxfw->has_output) {
426 		err = init_stream(oxfw, &oxfw->tx_stream);
427 		if (err < 0) {
428 			destroy_stream(oxfw, &oxfw->rx_stream);
429 			return err;
430 		}
431 	}
432 
433 	err = amdtp_domain_init(&oxfw->domain);
434 	if (err < 0) {
435 		destroy_stream(oxfw, &oxfw->rx_stream);
436 		if (oxfw->has_output)
437 			destroy_stream(oxfw, &oxfw->tx_stream);
438 	}
439 
440 	return err;
441 }
442 
443 // This function should be called before starting the stream or after stopping
444 // the streams.
445 void snd_oxfw_stream_destroy_duplex(struct snd_oxfw *oxfw)
446 {
447 	amdtp_domain_destroy(&oxfw->domain);
448 
449 	destroy_stream(oxfw, &oxfw->rx_stream);
450 
451 	if (oxfw->has_output)
452 		destroy_stream(oxfw, &oxfw->tx_stream);
453 }
454 
455 void snd_oxfw_stream_update_duplex(struct snd_oxfw *oxfw)
456 {
457 	amdtp_domain_stop(&oxfw->domain);
458 
459 	cmp_connection_break(&oxfw->in_conn);
460 
461 	amdtp_stream_pcm_abort(&oxfw->rx_stream);
462 
463 	if (oxfw->has_output) {
464 		cmp_connection_break(&oxfw->out_conn);
465 
466 		amdtp_stream_pcm_abort(&oxfw->tx_stream);
467 	}
468 }
469 
470 int snd_oxfw_stream_get_current_formation(struct snd_oxfw *oxfw,
471 				enum avc_general_plug_dir dir,
472 				struct snd_oxfw_stream_formation *formation)
473 {
474 	u8 *format;
475 	unsigned int len;
476 	int err;
477 
478 	len = AVC_GENERIC_FRAME_MAXIMUM_BYTES;
479 	format = kmalloc(len, GFP_KERNEL);
480 	if (format == NULL)
481 		return -ENOMEM;
482 
483 	err = avc_stream_get_format_single(oxfw->unit, dir, 0, format, &len);
484 	if (err < 0)
485 		goto end;
486 	if (len < 3) {
487 		err = -EIO;
488 		goto end;
489 	}
490 
491 	err = snd_oxfw_stream_parse_format(format, formation);
492 end:
493 	kfree(format);
494 	return err;
495 }
496 
497 /*
498  * See Table 6.16 - AM824 Stream Format
499  *     Figure 6.19 - format_information field for AM824 Compound
500  * in AV/C Stream Format Information Specification 1.1 (Apr 2005, 1394TA)
501  * Also 'Clause 12 AM824 sequence adaption layers' in IEC 61883-6:2005
502  */
503 int snd_oxfw_stream_parse_format(u8 *format,
504 				 struct snd_oxfw_stream_formation *formation)
505 {
506 	unsigned int i, e, channels, type;
507 
508 	memset(formation, 0, sizeof(struct snd_oxfw_stream_formation));
509 
510 	/*
511 	 * this module can support a hierarchy combination that:
512 	 *  Root:	Audio and Music (0x90)
513 	 *  Level 1:	AM824 Compound  (0x40)
514 	 */
515 	if ((format[0] != 0x90) || (format[1] != 0x40))
516 		return -ENOSYS;
517 
518 	/* check the sampling rate */
519 	for (i = 0; i < ARRAY_SIZE(avc_stream_rate_table); i++) {
520 		if (format[2] == avc_stream_rate_table[i])
521 			break;
522 	}
523 	if (i == ARRAY_SIZE(avc_stream_rate_table))
524 		return -ENOSYS;
525 
526 	formation->rate = oxfw_rate_table[i];
527 
528 	for (e = 0; e < format[4]; e++) {
529 		channels = format[5 + e * 2];
530 		type = format[6 + e * 2];
531 
532 		switch (type) {
533 		/* IEC 60958 Conformant, currently handled as MBLA */
534 		case 0x00:
535 		/* Multi Bit Linear Audio (Raw) */
536 		case 0x06:
537 			formation->pcm += channels;
538 			break;
539 		/* MIDI Conformant */
540 		case 0x0d:
541 			formation->midi = channels;
542 			break;
543 		/* IEC 61937-3 to 7 */
544 		case 0x01:
545 		case 0x02:
546 		case 0x03:
547 		case 0x04:
548 		case 0x05:
549 		/* Multi Bit Linear Audio */
550 		case 0x07:	/* DVD-Audio */
551 		case 0x0c:	/* High Precision */
552 		/* One Bit Audio */
553 		case 0x08:	/* (Plain) Raw */
554 		case 0x09:	/* (Plain) SACD */
555 		case 0x0a:	/* (Encoded) Raw */
556 		case 0x0b:	/* (Encoded) SACD */
557 		/* SMPTE Time-Code conformant */
558 		case 0x0e:
559 		/* Sample Count */
560 		case 0x0f:
561 		/* Anciliary Data */
562 		case 0x10:
563 		/* Synchronization Stream (Stereo Raw audio) */
564 		case 0x40:
565 		/* Don't care */
566 		case 0xff:
567 		default:
568 			return -ENOSYS;	/* not supported */
569 		}
570 	}
571 
572 	if (formation->pcm  > AM824_MAX_CHANNELS_FOR_PCM ||
573 	    formation->midi > AM824_MAX_CHANNELS_FOR_MIDI)
574 		return -ENOSYS;
575 
576 	return 0;
577 }
578 
579 static int
580 assume_stream_formats(struct snd_oxfw *oxfw, enum avc_general_plug_dir dir,
581 		      unsigned int pid, u8 *buf, unsigned int *len,
582 		      u8 **formats)
583 {
584 	struct snd_oxfw_stream_formation formation;
585 	unsigned int i, eid;
586 	int err;
587 
588 	/* get format at current sampling rate */
589 	err = avc_stream_get_format_single(oxfw->unit, dir, pid, buf, len);
590 	if (err < 0) {
591 		dev_err(&oxfw->unit->device,
592 		"fail to get current stream format for isoc %s plug %d:%d\n",
593 			(dir == AVC_GENERAL_PLUG_DIR_IN) ? "in" : "out",
594 			pid, err);
595 		goto end;
596 	}
597 
598 	/* parse and set stream format */
599 	eid = 0;
600 	err = snd_oxfw_stream_parse_format(buf, &formation);
601 	if (err < 0)
602 		goto end;
603 
604 	formats[eid] = devm_kmemdup(&oxfw->card->card_dev, buf, *len,
605 				    GFP_KERNEL);
606 	if (!formats[eid]) {
607 		err = -ENOMEM;
608 		goto end;
609 	}
610 
611 	/* apply the format for each available sampling rate */
612 	for (i = 0; i < ARRAY_SIZE(oxfw_rate_table); i++) {
613 		if (formation.rate == oxfw_rate_table[i])
614 			continue;
615 
616 		err = avc_general_inquiry_sig_fmt(oxfw->unit,
617 						  oxfw_rate_table[i],
618 						  dir, pid);
619 		if (err < 0)
620 			continue;
621 
622 		eid++;
623 		formats[eid] = devm_kmemdup(&oxfw->card->card_dev, buf, *len,
624 					    GFP_KERNEL);
625 		if (formats[eid] == NULL) {
626 			err = -ENOMEM;
627 			goto end;
628 		}
629 		formats[eid][2] = avc_stream_rate_table[i];
630 	}
631 
632 	err = 0;
633 	oxfw->assumed = true;
634 end:
635 	return err;
636 }
637 
638 static int fill_stream_formats(struct snd_oxfw *oxfw,
639 			       enum avc_general_plug_dir dir,
640 			       unsigned short pid)
641 {
642 	u8 *buf, **formats;
643 	unsigned int len, eid = 0;
644 	struct snd_oxfw_stream_formation dummy;
645 	int err;
646 
647 	buf = kmalloc(AVC_GENERIC_FRAME_MAXIMUM_BYTES, GFP_KERNEL);
648 	if (buf == NULL)
649 		return -ENOMEM;
650 
651 	if (dir == AVC_GENERAL_PLUG_DIR_OUT)
652 		formats = oxfw->tx_stream_formats;
653 	else
654 		formats = oxfw->rx_stream_formats;
655 
656 	/* get first entry */
657 	len = AVC_GENERIC_FRAME_MAXIMUM_BYTES;
658 	err = avc_stream_get_format_list(oxfw->unit, dir, 0, buf, &len, 0);
659 	if (err == -ENOSYS) {
660 		/* LIST subfunction is not implemented */
661 		len = AVC_GENERIC_FRAME_MAXIMUM_BYTES;
662 		err = assume_stream_formats(oxfw, dir, pid, buf, &len,
663 					    formats);
664 		goto end;
665 	} else if (err < 0) {
666 		dev_err(&oxfw->unit->device,
667 			"fail to get stream format %d for isoc %s plug %d:%d\n",
668 			eid, (dir == AVC_GENERAL_PLUG_DIR_IN) ? "in" : "out",
669 			pid, err);
670 		goto end;
671 	}
672 
673 	/* LIST subfunction is implemented */
674 	while (eid < SND_OXFW_STREAM_FORMAT_ENTRIES) {
675 		/* The format is too short. */
676 		if (len < 3) {
677 			err = -EIO;
678 			break;
679 		}
680 
681 		/* parse and set stream format */
682 		err = snd_oxfw_stream_parse_format(buf, &dummy);
683 		if (err < 0)
684 			break;
685 
686 		formats[eid] = devm_kmemdup(&oxfw->card->card_dev, buf, len,
687 					    GFP_KERNEL);
688 		if (!formats[eid]) {
689 			err = -ENOMEM;
690 			break;
691 		}
692 
693 		/* get next entry */
694 		len = AVC_GENERIC_FRAME_MAXIMUM_BYTES;
695 		err = avc_stream_get_format_list(oxfw->unit, dir, 0,
696 						 buf, &len, ++eid);
697 		/* No entries remained. */
698 		if (err == -EINVAL) {
699 			err = 0;
700 			break;
701 		} else if (err < 0) {
702 			dev_err(&oxfw->unit->device,
703 			"fail to get stream format %d for isoc %s plug %d:%d\n",
704 				eid, (dir == AVC_GENERAL_PLUG_DIR_IN) ? "in" :
705 									"out",
706 				pid, err);
707 			break;
708 		}
709 	}
710 end:
711 	kfree(buf);
712 	return err;
713 }
714 
715 int snd_oxfw_stream_discover(struct snd_oxfw *oxfw)
716 {
717 	u8 plugs[AVC_PLUG_INFO_BUF_BYTES];
718 	struct snd_oxfw_stream_formation formation;
719 	u8 *format;
720 	unsigned int i;
721 	int err;
722 
723 	/* the number of plugs for isoc in/out, ext in/out  */
724 	err = avc_general_get_plug_info(oxfw->unit, 0x1f, 0x07, 0x00, plugs);
725 	if (err < 0) {
726 		dev_err(&oxfw->unit->device,
727 		"fail to get info for isoc/external in/out plugs: %d\n",
728 			err);
729 		goto end;
730 	} else if ((plugs[0] == 0) && (plugs[1] == 0)) {
731 		err = -ENOSYS;
732 		goto end;
733 	}
734 
735 	/* use oPCR[0] if exists */
736 	if (plugs[1] > 0) {
737 		err = fill_stream_formats(oxfw, AVC_GENERAL_PLUG_DIR_OUT, 0);
738 		if (err < 0)
739 			goto end;
740 
741 		for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) {
742 			format = oxfw->tx_stream_formats[i];
743 			if (format == NULL)
744 				continue;
745 			err = snd_oxfw_stream_parse_format(format, &formation);
746 			if (err < 0)
747 				continue;
748 
749 			/* Add one MIDI port. */
750 			if (formation.midi > 0)
751 				oxfw->midi_input_ports = 1;
752 		}
753 
754 		oxfw->has_output = true;
755 	}
756 
757 	/* use iPCR[0] if exists */
758 	if (plugs[0] > 0) {
759 		err = fill_stream_formats(oxfw, AVC_GENERAL_PLUG_DIR_IN, 0);
760 		if (err < 0)
761 			goto end;
762 
763 		for (i = 0; i < SND_OXFW_STREAM_FORMAT_ENTRIES; i++) {
764 			format = oxfw->rx_stream_formats[i];
765 			if (format == NULL)
766 				continue;
767 			err = snd_oxfw_stream_parse_format(format, &formation);
768 			if (err < 0)
769 				continue;
770 
771 			/* Add one MIDI port. */
772 			if (formation.midi > 0)
773 				oxfw->midi_output_ports = 1;
774 		}
775 	}
776 end:
777 	return err;
778 }
779 
780 void snd_oxfw_stream_lock_changed(struct snd_oxfw *oxfw)
781 {
782 	oxfw->dev_lock_changed = true;
783 	wake_up(&oxfw->hwdep_wait);
784 }
785 
786 int snd_oxfw_stream_lock_try(struct snd_oxfw *oxfw)
787 {
788 	int err;
789 
790 	spin_lock_irq(&oxfw->lock);
791 
792 	/* user land lock this */
793 	if (oxfw->dev_lock_count < 0) {
794 		err = -EBUSY;
795 		goto end;
796 	}
797 
798 	/* this is the first time */
799 	if (oxfw->dev_lock_count++ == 0)
800 		snd_oxfw_stream_lock_changed(oxfw);
801 	err = 0;
802 end:
803 	spin_unlock_irq(&oxfw->lock);
804 	return err;
805 }
806 
807 void snd_oxfw_stream_lock_release(struct snd_oxfw *oxfw)
808 {
809 	spin_lock_irq(&oxfw->lock);
810 
811 	if (WARN_ON(oxfw->dev_lock_count <= 0))
812 		goto end;
813 	if (--oxfw->dev_lock_count == 0)
814 		snd_oxfw_stream_lock_changed(oxfw);
815 end:
816 	spin_unlock_irq(&oxfw->lock);
817 }
818