1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2007, 2008 Karsten Wiese <fzu@wemgehoertderstaat.de>
4 */
5
6#include <linux/usb.h>
7#include <linux/gfp.h>
8
9#include "usb_stream.h"
10
11/* setup */
12
13static unsigned int usb_stream_next_packet_size(struct usb_stream_kernel *sk)
14{
15 struct usb_stream *s = sk->s;
16
17 sk->out_phase_peeked = (sk->out_phase & 0xffff) + sk->freqn;
18 return (sk->out_phase_peeked >> 16) * s->cfg.frame_size;
19}
20
21static void playback_prep_freqn(struct usb_stream_kernel *sk, struct urb *urb)
22{
23 struct usb_stream *s = sk->s;
24 int pack, lb = 0;
25
26 for (pack = 0; pack < sk->n_o_ps; pack++) {
27 int l = usb_stream_next_packet_size(sk);
28
29 if (s->idle_outsize + lb + l > s->period_size)
30 goto check;
31
32 sk->out_phase = sk->out_phase_peeked;
33 urb->iso_frame_desc[pack].offset = lb;
34 urb->iso_frame_desc[pack].length = l;
35 lb += l;
36 }
37 snd_printdd(KERN_DEBUG "%i\n", lb);
38
39check:
40 urb->number_of_packets = pack;
41 urb->transfer_buffer_length = lb;
42 s->idle_outsize += lb - s->period_size;
43 snd_printdd(KERN_DEBUG "idle=%i ul=%i ps=%i\n", s->idle_outsize,
44 lb, s->period_size);
45}
46
47static int init_pipe_urbs(struct usb_stream_kernel *sk,
48 unsigned int use_packsize,
49 struct urb **urbs, char *transfer,
50 struct usb_device *dev, int pipe)
51{
52 int u, p;
53 int maxpacket = use_packsize ?
54 use_packsize : usb_maxpacket(udev: dev, pipe);
55 int transfer_length = maxpacket * sk->n_o_ps;
56
57 for (u = 0; u < USB_STREAM_NURBS;
58 ++u, transfer += transfer_length) {
59 struct urb *urb = urbs[u];
60 struct usb_iso_packet_descriptor *desc;
61
62 urb->transfer_buffer = transfer;
63 urb->dev = dev;
64 urb->pipe = pipe;
65 urb->number_of_packets = sk->n_o_ps;
66 urb->context = sk;
67 urb->interval = 1;
68 if (usb_pipeout(pipe))
69 continue;
70 if (usb_urb_ep_type_check(urb))
71 return -EINVAL;
72
73 urb->transfer_buffer_length = transfer_length;
74 desc = urb->iso_frame_desc;
75 desc->offset = 0;
76 desc->length = maxpacket;
77 for (p = 1; p < sk->n_o_ps; ++p) {
78 desc[p].offset = desc[p - 1].offset + maxpacket;
79 desc[p].length = maxpacket;
80 }
81 }
82
83 return 0;
84}
85
86static int init_urbs(struct usb_stream_kernel *sk, unsigned int use_packsize,
87 struct usb_device *dev, int in_pipe, int out_pipe)
88{
89 struct usb_stream *s = sk->s;
90 char *indata =
91 (char *)s + sizeof(*s) + sizeof(struct usb_stream_packet) * s->inpackets;
92 int u;
93
94 for (u = 0; u < USB_STREAM_NURBS; ++u) {
95 sk->inurb[u] = usb_alloc_urb(iso_packets: sk->n_o_ps, GFP_KERNEL);
96 if (!sk->inurb[u])
97 return -ENOMEM;
98
99 sk->outurb[u] = usb_alloc_urb(iso_packets: sk->n_o_ps, GFP_KERNEL);
100 if (!sk->outurb[u])
101 return -ENOMEM;
102 }
103
104 if (init_pipe_urbs(sk, use_packsize, urbs: sk->inurb, transfer: indata, dev, pipe: in_pipe) ||
105 init_pipe_urbs(sk, use_packsize, urbs: sk->outurb, transfer: sk->write_page, dev,
106 pipe: out_pipe))
107 return -EINVAL;
108
109 return 0;
110}
111
112/*
113 * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
114 * this will overflow at approx 524 kHz
115 */
116static inline unsigned int get_usb_full_speed_rate(unsigned int rate)
117{
118 return ((rate << 13) + 62) / 125;
119}
120
121/*
122 * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
123 * this will overflow at approx 4 MHz
124 */
125static inline unsigned int get_usb_high_speed_rate(unsigned int rate)
126{
127 return ((rate << 10) + 62) / 125;
128}
129
130void usb_stream_free(struct usb_stream_kernel *sk)
131{
132 struct usb_stream *s;
133 unsigned int u;
134
135 for (u = 0; u < USB_STREAM_NURBS; ++u) {
136 usb_free_urb(urb: sk->inurb[u]);
137 sk->inurb[u] = NULL;
138 usb_free_urb(urb: sk->outurb[u]);
139 sk->outurb[u] = NULL;
140 }
141
142 s = sk->s;
143 if (!s)
144 return;
145
146 if (sk->write_page) {
147 free_pages_exact(virt: sk->write_page, size: s->write_size);
148 sk->write_page = NULL;
149 }
150
151 free_pages_exact(virt: s, size: s->read_size);
152 sk->s = NULL;
153}
154
155struct usb_stream *usb_stream_new(struct usb_stream_kernel *sk,
156 struct usb_device *dev,
157 unsigned int in_endpoint,
158 unsigned int out_endpoint,
159 unsigned int sample_rate,
160 unsigned int use_packsize,
161 unsigned int period_frames,
162 unsigned int frame_size)
163{
164 int packets, max_packsize;
165 int in_pipe, out_pipe;
166 int read_size = sizeof(struct usb_stream);
167 int write_size;
168 int usb_frames = dev->speed == USB_SPEED_HIGH ? 8000 : 1000;
169
170 in_pipe = usb_rcvisocpipe(dev, in_endpoint);
171 out_pipe = usb_sndisocpipe(dev, out_endpoint);
172
173 max_packsize = use_packsize ?
174 use_packsize : usb_maxpacket(udev: dev, pipe: in_pipe);
175
176 /*
177 t_period = period_frames / sample_rate
178 iso_packs = t_period / t_iso_frame
179 = (period_frames / sample_rate) * (1 / t_iso_frame)
180 */
181
182 packets = period_frames * usb_frames / sample_rate + 1;
183
184 if (dev->speed == USB_SPEED_HIGH)
185 packets = (packets + 7) & ~7;
186
187 read_size += packets * USB_STREAM_URBDEPTH *
188 (max_packsize + sizeof(struct usb_stream_packet));
189
190 max_packsize = usb_maxpacket(udev: dev, pipe: out_pipe);
191 write_size = max_packsize * packets * USB_STREAM_URBDEPTH;
192
193 if (read_size >= 256*PAGE_SIZE || write_size >= 256*PAGE_SIZE) {
194 snd_printk(KERN_WARNING "a size exceeds 128*PAGE_SIZE\n");
195 goto out;
196 }
197
198 sk->s = alloc_pages_exact(size: read_size,
199 GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
200 if (!sk->s) {
201 pr_warn("us122l: couldn't allocate read buffer\n");
202 goto out;
203 }
204 sk->s->cfg.version = USB_STREAM_INTERFACE_VERSION;
205
206 sk->s->read_size = read_size;
207
208 sk->s->cfg.sample_rate = sample_rate;
209 sk->s->cfg.frame_size = frame_size;
210 sk->n_o_ps = packets;
211 sk->s->inpackets = packets * USB_STREAM_URBDEPTH;
212 sk->s->cfg.period_frames = period_frames;
213 sk->s->period_size = frame_size * period_frames;
214
215 sk->s->write_size = write_size;
216
217 sk->write_page = alloc_pages_exact(size: write_size,
218 GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
219 if (!sk->write_page) {
220 pr_warn("us122l: couldn't allocate write buffer\n");
221 usb_stream_free(sk);
222 return NULL;
223 }
224
225 /* calculate the frequency in 16.16 format */
226 if (dev->speed == USB_SPEED_FULL)
227 sk->freqn = get_usb_full_speed_rate(rate: sample_rate);
228 else
229 sk->freqn = get_usb_high_speed_rate(rate: sample_rate);
230
231 if (init_urbs(sk, use_packsize, dev, in_pipe, out_pipe) < 0) {
232 usb_stream_free(sk);
233 return NULL;
234 }
235
236 sk->s->state = usb_stream_stopped;
237out:
238 return sk->s;
239}
240
241/* start */
242
243static bool balance_check(struct usb_stream_kernel *sk, struct urb *urb)
244{
245 bool r;
246
247 if (unlikely(urb->status)) {
248 if (urb->status != -ESHUTDOWN && urb->status != -ENOENT)
249 snd_printk(KERN_WARNING "status=%i\n", urb->status);
250 sk->iso_frame_balance = 0x7FFFFFFF;
251 return false;
252 }
253 r = sk->iso_frame_balance == 0;
254 if (!r)
255 sk->i_urb = urb;
256 return r;
257}
258
259static bool balance_playback(struct usb_stream_kernel *sk, struct urb *urb)
260{
261 sk->iso_frame_balance += urb->number_of_packets;
262 return balance_check(sk, urb);
263}
264
265static bool balance_capture(struct usb_stream_kernel *sk, struct urb *urb)
266{
267 sk->iso_frame_balance -= urb->number_of_packets;
268 return balance_check(sk, urb);
269}
270
271static void subs_set_complete(struct urb **urbs, void (*complete)(struct urb *))
272{
273 int u;
274
275 for (u = 0; u < USB_STREAM_NURBS; u++) {
276 struct urb *urb = urbs[u];
277
278 urb->complete = complete;
279 }
280}
281
282static int usb_stream_prepare_playback(struct usb_stream_kernel *sk,
283 struct urb *inurb)
284{
285 struct usb_stream *s = sk->s;
286 struct urb *io;
287 struct usb_iso_packet_descriptor *id, *od;
288 int p = 0, lb = 0, l = 0;
289
290 io = sk->idle_outurb;
291 od = io->iso_frame_desc;
292
293 for (; s->sync_packet < 0; ++p, ++s->sync_packet) {
294 struct urb *ii = sk->completed_inurb;
295
296 id = ii->iso_frame_desc +
297 ii->number_of_packets + s->sync_packet;
298 l = id->actual_length;
299
300 od[p].length = l;
301 od[p].offset = lb;
302 lb += l;
303 }
304
305 for (;
306 s->sync_packet < inurb->number_of_packets && p < sk->n_o_ps;
307 ++p, ++s->sync_packet) {
308 l = inurb->iso_frame_desc[s->sync_packet].actual_length;
309
310 if (s->idle_outsize + lb + l > s->period_size)
311 goto check_ok;
312
313 od[p].length = l;
314 od[p].offset = lb;
315 lb += l;
316 }
317
318check_ok:
319 s->sync_packet -= inurb->number_of_packets;
320 if (unlikely(s->sync_packet < -2 || s->sync_packet > 0)) {
321 snd_printk(KERN_WARNING "invalid sync_packet = %i;"
322 " p=%i nop=%i %i %x %x %x > %x\n",
323 s->sync_packet, p, inurb->number_of_packets,
324 s->idle_outsize + lb + l,
325 s->idle_outsize, lb, l,
326 s->period_size);
327 return -1;
328 }
329 if (unlikely(lb % s->cfg.frame_size)) {
330 snd_printk(KERN_WARNING"invalid outsize = %i\n",
331 lb);
332 return -1;
333 }
334 s->idle_outsize += lb - s->period_size;
335 io->number_of_packets = p;
336 io->transfer_buffer_length = lb;
337 if (s->idle_outsize <= 0)
338 return 0;
339
340 snd_printk(KERN_WARNING "idle=%i\n", s->idle_outsize);
341 return -1;
342}
343
344static void prepare_inurb(int number_of_packets, struct urb *iu)
345{
346 struct usb_iso_packet_descriptor *id;
347 int p;
348
349 iu->number_of_packets = number_of_packets;
350 id = iu->iso_frame_desc;
351 id->offset = 0;
352 for (p = 0; p < iu->number_of_packets - 1; ++p)
353 id[p + 1].offset = id[p].offset + id[p].length;
354
355 iu->transfer_buffer_length =
356 id[0].length * iu->number_of_packets;
357}
358
359static int submit_urbs(struct usb_stream_kernel *sk,
360 struct urb *inurb, struct urb *outurb)
361{
362 int err;
363
364 prepare_inurb(number_of_packets: sk->idle_outurb->number_of_packets, iu: sk->idle_inurb);
365 err = usb_submit_urb(urb: sk->idle_inurb, GFP_ATOMIC);
366 if (err < 0)
367 goto report_failure;
368
369 sk->idle_inurb = sk->completed_inurb;
370 sk->completed_inurb = inurb;
371 err = usb_submit_urb(urb: sk->idle_outurb, GFP_ATOMIC);
372 if (err < 0)
373 goto report_failure;
374
375 sk->idle_outurb = sk->completed_outurb;
376 sk->completed_outurb = outurb;
377 return 0;
378
379report_failure:
380 snd_printk(KERN_ERR "%i\n", err);
381 return err;
382}
383
384#ifdef DEBUG_LOOP_BACK
385/*
386 This loop_back() shows how to read/write the period data.
387 */
388static void loop_back(struct usb_stream *s)
389{
390 char *i, *o;
391 int il, ol, l, p;
392 struct urb *iu;
393 struct usb_iso_packet_descriptor *id;
394
395 o = s->playback1st_to;
396 ol = s->playback1st_size;
397 l = 0;
398
399 if (s->insplit_pack >= 0) {
400 iu = sk->idle_inurb;
401 id = iu->iso_frame_desc;
402 p = s->insplit_pack;
403 } else
404 goto second;
405loop:
406 for (; p < iu->number_of_packets && l < s->period_size; ++p) {
407 i = iu->transfer_buffer + id[p].offset;
408 il = id[p].actual_length;
409 if (l + il > s->period_size)
410 il = s->period_size - l;
411 if (il <= ol) {
412 memcpy(o, i, il);
413 o += il;
414 ol -= il;
415 } else {
416 memcpy(o, i, ol);
417 singen_6pack(o, ol);
418 o = s->playback_to;
419 memcpy(o, i + ol, il - ol);
420 o += il - ol;
421 ol = s->period_size - s->playback1st_size;
422 }
423 l += il;
424 }
425 if (iu == sk->completed_inurb) {
426 if (l != s->period_size)
427 printk(KERN_DEBUG"%s:%i %i\n", __func__, __LINE__,
428 l/(int)s->cfg.frame_size);
429
430 return;
431 }
432second:
433 iu = sk->completed_inurb;
434 id = iu->iso_frame_desc;
435 p = 0;
436 goto loop;
437
438}
439#else
440static void loop_back(struct usb_stream *s)
441{
442}
443#endif
444
445static void stream_idle(struct usb_stream_kernel *sk,
446 struct urb *inurb, struct urb *outurb)
447{
448 struct usb_stream *s = sk->s;
449 int l, p;
450 int insize = s->idle_insize;
451 int urb_size = 0;
452
453 s->inpacket_split = s->next_inpacket_split;
454 s->inpacket_split_at = s->next_inpacket_split_at;
455 s->next_inpacket_split = -1;
456 s->next_inpacket_split_at = 0;
457
458 for (p = 0; p < inurb->number_of_packets; ++p) {
459 struct usb_iso_packet_descriptor *id = inurb->iso_frame_desc;
460
461 l = id[p].actual_length;
462 if (unlikely(l == 0 || id[p].status)) {
463 snd_printk(KERN_WARNING "underrun, status=%u\n",
464 id[p].status);
465 goto err_out;
466 }
467 s->inpacket_head++;
468 s->inpacket_head %= s->inpackets;
469 if (s->inpacket_split == -1)
470 s->inpacket_split = s->inpacket_head;
471
472 s->inpacket[s->inpacket_head].offset =
473 id[p].offset + (inurb->transfer_buffer - (void *)s);
474 s->inpacket[s->inpacket_head].length = l;
475 if (insize + l > s->period_size &&
476 s->next_inpacket_split == -1) {
477 s->next_inpacket_split = s->inpacket_head;
478 s->next_inpacket_split_at = s->period_size - insize;
479 }
480 insize += l;
481 urb_size += l;
482 }
483 s->idle_insize += urb_size - s->period_size;
484 if (s->idle_insize < 0) {
485 snd_printk(KERN_WARNING "%i\n",
486 (s->idle_insize)/(int)s->cfg.frame_size);
487 goto err_out;
488 }
489 s->insize_done += urb_size;
490
491 l = s->idle_outsize;
492 s->outpacket[0].offset = (sk->idle_outurb->transfer_buffer -
493 sk->write_page) - l;
494
495 if (usb_stream_prepare_playback(sk, inurb) < 0)
496 goto err_out;
497
498 s->outpacket[0].length = sk->idle_outurb->transfer_buffer_length + l;
499 s->outpacket[1].offset = sk->completed_outurb->transfer_buffer -
500 sk->write_page;
501
502 if (submit_urbs(sk, inurb, outurb) < 0)
503 goto err_out;
504
505 loop_back(s);
506 s->periods_done++;
507 wake_up_all(&sk->sleep);
508 return;
509err_out:
510 s->state = usb_stream_xrun;
511 wake_up_all(&sk->sleep);
512}
513
514static void i_capture_idle(struct urb *urb)
515{
516 struct usb_stream_kernel *sk = urb->context;
517
518 if (balance_capture(sk, urb))
519 stream_idle(sk, inurb: urb, outurb: sk->i_urb);
520}
521
522static void i_playback_idle(struct urb *urb)
523{
524 struct usb_stream_kernel *sk = urb->context;
525
526 if (balance_playback(sk, urb))
527 stream_idle(sk, inurb: sk->i_urb, outurb: urb);
528}
529
530static void stream_start(struct usb_stream_kernel *sk,
531 struct urb *inurb, struct urb *outurb)
532{
533 struct usb_stream *s = sk->s;
534
535 if (s->state >= usb_stream_sync1) {
536 int l, p, max_diff, max_diff_0;
537 int urb_size = 0;
538 unsigned int frames_per_packet, min_frames = 0;
539
540 frames_per_packet = (s->period_size - s->idle_insize);
541 frames_per_packet <<= 8;
542 frames_per_packet /=
543 s->cfg.frame_size * inurb->number_of_packets;
544 frames_per_packet++;
545
546 max_diff_0 = s->cfg.frame_size;
547 if (s->cfg.period_frames >= 256)
548 max_diff_0 <<= 1;
549 if (s->cfg.period_frames >= 1024)
550 max_diff_0 <<= 1;
551 max_diff = max_diff_0;
552 for (p = 0; p < inurb->number_of_packets; ++p) {
553 int diff;
554
555 l = inurb->iso_frame_desc[p].actual_length;
556 urb_size += l;
557
558 min_frames += frames_per_packet;
559 diff = urb_size -
560 (min_frames >> 8) * s->cfg.frame_size;
561 if (diff < max_diff) {
562 snd_printdd(KERN_DEBUG "%i %i %i %i\n",
563 s->insize_done,
564 urb_size / (int)s->cfg.frame_size,
565 inurb->number_of_packets, diff);
566 max_diff = diff;
567 }
568 }
569 s->idle_insize -= max_diff - max_diff_0;
570 s->idle_insize += urb_size - s->period_size;
571 if (s->idle_insize < 0) {
572 snd_printk(KERN_WARNING "%i %i %i\n",
573 s->idle_insize, urb_size, s->period_size);
574 return;
575 } else if (s->idle_insize == 0) {
576 s->next_inpacket_split =
577 (s->inpacket_head + 1) % s->inpackets;
578 s->next_inpacket_split_at = 0;
579 } else {
580 unsigned int split = s->inpacket_head;
581
582 l = s->idle_insize;
583 while (l > s->inpacket[split].length) {
584 l -= s->inpacket[split].length;
585 if (split == 0)
586 split = s->inpackets - 1;
587 else
588 split--;
589 }
590 s->next_inpacket_split = split;
591 s->next_inpacket_split_at =
592 s->inpacket[split].length - l;
593 }
594
595 s->insize_done += urb_size;
596
597 if (usb_stream_prepare_playback(sk, inurb) < 0)
598 return;
599
600 } else
601 playback_prep_freqn(sk, urb: sk->idle_outurb);
602
603 if (submit_urbs(sk, inurb, outurb) < 0)
604 return;
605
606 if (s->state == usb_stream_sync1 && s->insize_done > 360000) {
607 /* just guesswork ^^^^^^ */
608 s->state = usb_stream_ready;
609 subs_set_complete(urbs: sk->inurb, complete: i_capture_idle);
610 subs_set_complete(urbs: sk->outurb, complete: i_playback_idle);
611 }
612}
613
614static void i_capture_start(struct urb *urb)
615{
616 struct usb_iso_packet_descriptor *id = urb->iso_frame_desc;
617 struct usb_stream_kernel *sk = urb->context;
618 struct usb_stream *s = sk->s;
619 int p;
620 int empty = 0;
621
622 if (urb->status) {
623 snd_printk(KERN_WARNING "status=%i\n", urb->status);
624 return;
625 }
626
627 for (p = 0; p < urb->number_of_packets; ++p) {
628 int l = id[p].actual_length;
629
630 if (l < s->cfg.frame_size) {
631 ++empty;
632 if (s->state >= usb_stream_sync0) {
633 snd_printk(KERN_WARNING "%i\n", l);
634 return;
635 }
636 }
637 s->inpacket_head++;
638 s->inpacket_head %= s->inpackets;
639 s->inpacket[s->inpacket_head].offset =
640 id[p].offset + (urb->transfer_buffer - (void *)s);
641 s->inpacket[s->inpacket_head].length = l;
642 }
643#ifdef SHOW_EMPTY
644 if (empty) {
645 printk(KERN_DEBUG"%s:%i: %i", __func__, __LINE__,
646 urb->iso_frame_desc[0].actual_length);
647 for (pack = 1; pack < urb->number_of_packets; ++pack) {
648 int l = urb->iso_frame_desc[pack].actual_length;
649
650 printk(KERN_CONT " %i", l);
651 }
652 printk(KERN_CONT "\n");
653 }
654#endif
655 if (!empty && s->state < usb_stream_sync1)
656 ++s->state;
657
658 if (balance_capture(sk, urb))
659 stream_start(sk, inurb: urb, outurb: sk->i_urb);
660}
661
662static void i_playback_start(struct urb *urb)
663{
664 struct usb_stream_kernel *sk = urb->context;
665
666 if (balance_playback(sk, urb))
667 stream_start(sk, inurb: sk->i_urb, outurb: urb);
668}
669
670int usb_stream_start(struct usb_stream_kernel *sk)
671{
672 struct usb_stream *s = sk->s;
673 int frame = 0, iters = 0;
674 int u, err;
675 int try = 0;
676
677 if (s->state != usb_stream_stopped)
678 return -EAGAIN;
679
680 subs_set_complete(urbs: sk->inurb, complete: i_capture_start);
681 subs_set_complete(urbs: sk->outurb, complete: i_playback_start);
682 memset(sk->write_page, 0, s->write_size);
683dotry:
684 s->insize_done = 0;
685 s->idle_insize = 0;
686 s->idle_outsize = 0;
687 s->sync_packet = -1;
688 s->inpacket_head = -1;
689 sk->iso_frame_balance = 0;
690 ++try;
691 for (u = 0; u < 2; u++) {
692 struct urb *inurb = sk->inurb[u];
693 struct urb *outurb = sk->outurb[u];
694
695 playback_prep_freqn(sk, urb: outurb);
696 inurb->number_of_packets = outurb->number_of_packets;
697 inurb->transfer_buffer_length =
698 inurb->number_of_packets *
699 inurb->iso_frame_desc[0].length;
700
701 if (u == 0) {
702 int now;
703 struct usb_device *dev = inurb->dev;
704
705 frame = usb_get_current_frame_number(usb_dev: dev);
706 do {
707 now = usb_get_current_frame_number(usb_dev: dev);
708 ++iters;
709 } while (now > -1 && now == frame);
710 }
711 err = usb_submit_urb(urb: inurb, GFP_ATOMIC);
712 if (err < 0) {
713 snd_printk(KERN_ERR
714 "usb_submit_urb(sk->inurb[%i]) returned %i\n",
715 u, err);
716 return err;
717 }
718 err = usb_submit_urb(urb: outurb, GFP_ATOMIC);
719 if (err < 0) {
720 snd_printk(KERN_ERR
721 "usb_submit_urb(sk->outurb[%i]) returned %i\n",
722 u, err);
723 return err;
724 }
725
726 if (inurb->start_frame != outurb->start_frame) {
727 snd_printd(KERN_DEBUG
728 "u[%i] start_frames differ in:%u out:%u\n",
729 u, inurb->start_frame, outurb->start_frame);
730 goto check_retry;
731 }
732 }
733 snd_printdd(KERN_DEBUG "%i %i\n", frame, iters);
734 try = 0;
735check_retry:
736 if (try) {
737 usb_stream_stop(sk);
738 if (try < 5) {
739 msleep(msecs: 1500);
740 snd_printd(KERN_DEBUG "goto dotry;\n");
741 goto dotry;
742 }
743 snd_printk(KERN_WARNING
744 "couldn't start all urbs on the same start_frame.\n");
745 return -EFAULT;
746 }
747
748 sk->idle_inurb = sk->inurb[USB_STREAM_NURBS - 2];
749 sk->idle_outurb = sk->outurb[USB_STREAM_NURBS - 2];
750 sk->completed_inurb = sk->inurb[USB_STREAM_NURBS - 1];
751 sk->completed_outurb = sk->outurb[USB_STREAM_NURBS - 1];
752
753/* wait, check */
754 {
755 int wait_ms = 3000;
756
757 while (s->state != usb_stream_ready && wait_ms > 0) {
758 snd_printdd(KERN_DEBUG "%i\n", s->state);
759 msleep(msecs: 200);
760 wait_ms -= 200;
761 }
762 }
763
764 return s->state == usb_stream_ready ? 0 : -EFAULT;
765}
766
767
768/* stop */
769
770void usb_stream_stop(struct usb_stream_kernel *sk)
771{
772 int u;
773
774 if (!sk->s)
775 return;
776 for (u = 0; u < USB_STREAM_NURBS; ++u) {
777 usb_kill_urb(urb: sk->inurb[u]);
778 usb_kill_urb(urb: sk->outurb[u]);
779 }
780 sk->s->state = usb_stream_stopped;
781 msleep(msecs: 400);
782}
783

source code of linux/sound/usb/usx2y/usb_stream.c