xref: /openbmc/linux/sound/usb/usx2y/usb_stream.c (revision 74a22e8f)
1 /*
2  * Copyright (C) 2007, 2008 Karsten Wiese <fzu@wemgehoertderstaat.de>
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms of the GNU General Public License as published by the
6  * Free Software Foundation; either version 2 of the License, or (at your
7  * option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful, but
10  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
11  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12  * for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software Foundation,
16  * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17  */
18 
19 #include <linux/usb.h>
20 #include <linux/gfp.h>
21 
22 #include "usb_stream.h"
23 
24 
25 /*                             setup                                  */
26 
27 static unsigned usb_stream_next_packet_size(struct usb_stream_kernel *sk)
28 {
29 	struct usb_stream *s = sk->s;
30 	sk->out_phase_peeked = (sk->out_phase & 0xffff) + sk->freqn;
31 	return (sk->out_phase_peeked >> 16) * s->cfg.frame_size;
32 }
33 
34 static void playback_prep_freqn(struct usb_stream_kernel *sk, struct urb *urb)
35 {
36 	struct usb_stream *s = sk->s;
37 	int pack, lb = 0;
38 
39 	for (pack = 0; pack < sk->n_o_ps; pack++) {
40 		int l = usb_stream_next_packet_size(sk);
41 		if (s->idle_outsize + lb + l > s->period_size)
42 			goto check;
43 
44 		sk->out_phase = sk->out_phase_peeked;
45 		urb->iso_frame_desc[pack].offset = lb;
46 		urb->iso_frame_desc[pack].length = l;
47 		lb += l;
48 	}
49 	snd_printdd(KERN_DEBUG "%i\n", lb);
50 
51 check:
52 	urb->number_of_packets = pack;
53 	urb->transfer_buffer_length = lb;
54 	s->idle_outsize += lb - s->period_size;
55 	snd_printdd(KERN_DEBUG "idle=%i ul=%i ps=%i\n", s->idle_outsize,
56 		    lb, s->period_size);
57 }
58 
59 static int init_pipe_urbs(struct usb_stream_kernel *sk, unsigned use_packsize,
60 			   struct urb **urbs, char *transfer,
61 			   struct usb_device *dev, int pipe)
62 {
63 	int u, p;
64 	int maxpacket = use_packsize ?
65 		use_packsize : usb_maxpacket(dev, pipe, usb_pipeout(pipe));
66 	int transfer_length = maxpacket * sk->n_o_ps;
67 
68 	for (u = 0; u < USB_STREAM_NURBS;
69 	     ++u, transfer += transfer_length) {
70 		struct urb *urb = urbs[u];
71 		struct usb_iso_packet_descriptor *desc;
72 		urb->transfer_buffer = transfer;
73 		urb->dev = dev;
74 		urb->pipe = pipe;
75 		urb->number_of_packets = sk->n_o_ps;
76 		urb->context = sk;
77 		urb->interval = 1;
78 		if (usb_pipeout(pipe))
79 			continue;
80 		if (usb_urb_ep_type_check(urb))
81 			return -EINVAL;
82 
83 		urb->transfer_buffer_length = transfer_length;
84 		desc = urb->iso_frame_desc;
85 		desc->offset = 0;
86 		desc->length = maxpacket;
87 		for (p = 1; p < sk->n_o_ps; ++p) {
88 			desc[p].offset = desc[p - 1].offset + maxpacket;
89 			desc[p].length = maxpacket;
90 		}
91 	}
92 
93 	return 0;
94 }
95 
96 static int init_urbs(struct usb_stream_kernel *sk, unsigned use_packsize,
97 		      struct usb_device *dev, int in_pipe, int out_pipe)
98 {
99 	struct usb_stream	*s = sk->s;
100 	char			*indata = (char *)s + sizeof(*s) +
101 					sizeof(struct usb_stream_packet) *
102 					s->inpackets;
103 	int			u;
104 
105 	for (u = 0; u < USB_STREAM_NURBS; ++u) {
106 		sk->inurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
107 		if (!sk->inurb[u])
108 			return -ENOMEM;
109 
110 		sk->outurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
111 		if (!sk->outurb[u])
112 			return -ENOMEM;
113 	}
114 
115 	if (init_pipe_urbs(sk, use_packsize, sk->inurb, indata, dev, in_pipe) ||
116 	    init_pipe_urbs(sk, use_packsize, sk->outurb, sk->write_page, dev,
117 			   out_pipe))
118 		return -EINVAL;
119 
120 	return 0;
121 }
122 
123 
124 /*
125  * convert a sampling rate into our full speed format (fs/1000 in Q16.16)
126  * this will overflow at approx 524 kHz
127  */
128 static inline unsigned get_usb_full_speed_rate(unsigned rate)
129 {
130 	return ((rate << 13) + 62) / 125;
131 }
132 
133 /*
134  * convert a sampling rate into USB high speed format (fs/8000 in Q16.16)
135  * this will overflow at approx 4 MHz
136  */
137 static inline unsigned get_usb_high_speed_rate(unsigned rate)
138 {
139 	return ((rate << 10) + 62) / 125;
140 }
141 
142 void usb_stream_free(struct usb_stream_kernel *sk)
143 {
144 	struct usb_stream *s;
145 	unsigned u;
146 
147 	for (u = 0; u < USB_STREAM_NURBS; ++u) {
148 		usb_free_urb(sk->inurb[u]);
149 		sk->inurb[u] = NULL;
150 		usb_free_urb(sk->outurb[u]);
151 		sk->outurb[u] = NULL;
152 	}
153 
154 	s = sk->s;
155 	if (!s)
156 		return;
157 
158 	free_pages_exact(sk->write_page, s->write_size);
159 	sk->write_page = NULL;
160 	free_pages_exact(s, s->read_size);
161 	sk->s = NULL;
162 }
163 
164 struct usb_stream *usb_stream_new(struct usb_stream_kernel *sk,
165 				  struct usb_device *dev,
166 				  unsigned in_endpoint, unsigned out_endpoint,
167 				  unsigned sample_rate, unsigned use_packsize,
168 				  unsigned period_frames, unsigned frame_size)
169 {
170 	int packets, max_packsize;
171 	int in_pipe, out_pipe;
172 	int read_size = sizeof(struct usb_stream);
173 	int write_size;
174 	int usb_frames = dev->speed == USB_SPEED_HIGH ? 8000 : 1000;
175 
176 	in_pipe = usb_rcvisocpipe(dev, in_endpoint);
177 	out_pipe = usb_sndisocpipe(dev, out_endpoint);
178 
179 	max_packsize = use_packsize ?
180 		use_packsize : usb_maxpacket(dev, in_pipe, 0);
181 
182 	/*
183 		t_period = period_frames / sample_rate
184 		iso_packs = t_period / t_iso_frame
185 			= (period_frames / sample_rate) * (1 / t_iso_frame)
186 	*/
187 
188 	packets = period_frames * usb_frames / sample_rate + 1;
189 
190 	if (dev->speed == USB_SPEED_HIGH)
191 		packets = (packets + 7) & ~7;
192 
193 	read_size += packets * USB_STREAM_URBDEPTH *
194 		(max_packsize + sizeof(struct usb_stream_packet));
195 
196 	max_packsize = usb_maxpacket(dev, out_pipe, 1);
197 	write_size = max_packsize * packets * USB_STREAM_URBDEPTH;
198 
199 	if (read_size >= 256*PAGE_SIZE || write_size >= 256*PAGE_SIZE) {
200 		snd_printk(KERN_WARNING "a size exceeds 128*PAGE_SIZE\n");
201 		goto out;
202 	}
203 
204 	sk->s = alloc_pages_exact(read_size,
205 				  GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
206 	if (!sk->s) {
207 		pr_warn("us122l: couldn't allocate read buffer\n");
208 		goto out;
209 	}
210 	sk->s->cfg.version = USB_STREAM_INTERFACE_VERSION;
211 
212 	sk->s->read_size = read_size;
213 
214 	sk->s->cfg.sample_rate = sample_rate;
215 	sk->s->cfg.frame_size = frame_size;
216 	sk->n_o_ps = packets;
217 	sk->s->inpackets = packets * USB_STREAM_URBDEPTH;
218 	sk->s->cfg.period_frames = period_frames;
219 	sk->s->period_size = frame_size * period_frames;
220 
221 	sk->s->write_size = write_size;
222 
223 	sk->write_page = alloc_pages_exact(write_size,
224 					   GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
225 	if (!sk->write_page) {
226 		pr_warn("us122l: couldn't allocate write buffer\n");
227 		usb_stream_free(sk);
228 		return NULL;
229 	}
230 
231 	/* calculate the frequency in 16.16 format */
232 	if (dev->speed == USB_SPEED_FULL)
233 		sk->freqn = get_usb_full_speed_rate(sample_rate);
234 	else
235 		sk->freqn = get_usb_high_speed_rate(sample_rate);
236 
237 	if (init_urbs(sk, use_packsize, dev, in_pipe, out_pipe) < 0) {
238 		usb_stream_free(sk);
239 		return NULL;
240 	}
241 
242 	sk->s->state = usb_stream_stopped;
243 out:
244 	return sk->s;
245 }
246 
247 
248 /*                             start                                  */
249 
250 static bool balance_check(struct usb_stream_kernel *sk, struct urb *urb)
251 {
252 	bool r;
253 	if (unlikely(urb->status)) {
254 		if (urb->status != -ESHUTDOWN && urb->status != -ENOENT)
255 			snd_printk(KERN_WARNING "status=%i\n", urb->status);
256 		sk->iso_frame_balance = 0x7FFFFFFF;
257 		return false;
258 	}
259 	r = sk->iso_frame_balance == 0;
260 	if (!r)
261 		sk->i_urb = urb;
262 	return r;
263 }
264 
265 static bool balance_playback(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 
271 static bool balance_capture(struct usb_stream_kernel *sk, struct urb *urb)
272 {
273 	sk->iso_frame_balance -= urb->number_of_packets;
274 	return balance_check(sk, urb);
275 }
276 
277 static void subs_set_complete(struct urb **urbs, void (*complete)(struct urb *))
278 {
279 	int u;
280 
281 	for (u = 0; u < USB_STREAM_NURBS; u++) {
282 		struct urb *urb = urbs[u];
283 		urb->complete = complete;
284 	}
285 }
286 
287 static int usb_stream_prepare_playback(struct usb_stream_kernel *sk,
288 		struct urb *inurb)
289 {
290 	struct usb_stream *s = sk->s;
291 	struct urb *io;
292 	struct usb_iso_packet_descriptor *id, *od;
293 	int p = 0, lb = 0, l = 0;
294 
295 	io = sk->idle_outurb;
296 	od = io->iso_frame_desc;
297 
298 	for (; s->sync_packet < 0; ++p, ++s->sync_packet) {
299 		struct urb *ii = sk->completed_inurb;
300 		id = ii->iso_frame_desc +
301 			ii->number_of_packets + s->sync_packet;
302 		l = id->actual_length;
303 
304 		od[p].length = l;
305 		od[p].offset = lb;
306 		lb += l;
307 	}
308 
309 	for (;
310 	     s->sync_packet < inurb->number_of_packets && p < sk->n_o_ps;
311 	     ++p, ++s->sync_packet) {
312 		l = inurb->iso_frame_desc[s->sync_packet].actual_length;
313 
314 		if (s->idle_outsize + lb + l > s->period_size)
315 			goto check_ok;
316 
317 		od[p].length = l;
318 		od[p].offset = lb;
319 		lb += l;
320 	}
321 
322 check_ok:
323 	s->sync_packet -= inurb->number_of_packets;
324 	if (unlikely(s->sync_packet < -2 || s->sync_packet > 0)) {
325 		snd_printk(KERN_WARNING "invalid sync_packet = %i;"
326 			   " p=%i nop=%i %i %x %x %x > %x\n",
327 			   s->sync_packet, p, inurb->number_of_packets,
328 			   s->idle_outsize + lb + l,
329 			   s->idle_outsize, lb,  l,
330 			   s->period_size);
331 		return -1;
332 	}
333 	if (unlikely(lb % s->cfg.frame_size)) {
334 		snd_printk(KERN_WARNING"invalid outsize = %i\n",
335 			   lb);
336 		return -1;
337 	}
338 	s->idle_outsize += lb - s->period_size;
339 	io->number_of_packets = p;
340 	io->transfer_buffer_length = lb;
341 	if (s->idle_outsize <= 0)
342 		return 0;
343 
344 	snd_printk(KERN_WARNING "idle=%i\n", s->idle_outsize);
345 	return -1;
346 }
347 
348 static void prepare_inurb(int number_of_packets, struct urb *iu)
349 {
350 	struct usb_iso_packet_descriptor *id;
351 	int p;
352 
353 	iu->number_of_packets = number_of_packets;
354 	id = iu->iso_frame_desc;
355 	id->offset = 0;
356 	for (p = 0; p < iu->number_of_packets - 1; ++p)
357 		id[p + 1].offset = id[p].offset + id[p].length;
358 
359 	iu->transfer_buffer_length =
360 		id[0].length * iu->number_of_packets;
361 }
362 
363 static int submit_urbs(struct usb_stream_kernel *sk,
364 		       struct urb *inurb, struct urb *outurb)
365 {
366 	int err;
367 	prepare_inurb(sk->idle_outurb->number_of_packets, sk->idle_inurb);
368 	err = usb_submit_urb(sk->idle_inurb, GFP_ATOMIC);
369 	if (err < 0)
370 		goto report_failure;
371 
372 	sk->idle_inurb = sk->completed_inurb;
373 	sk->completed_inurb = inurb;
374 	err = usb_submit_urb(sk->idle_outurb, GFP_ATOMIC);
375 	if (err < 0)
376 		goto report_failure;
377 
378 	sk->idle_outurb = sk->completed_outurb;
379 	sk->completed_outurb = outurb;
380 	return 0;
381 
382 report_failure:
383 	snd_printk(KERN_ERR "%i\n", err);
384 	return err;
385 }
386 
387 #ifdef DEBUG_LOOP_BACK
388 /*
389   This loop_back() shows how to read/write the period data.
390  */
391 static void loop_back(struct usb_stream *s)
392 {
393 	char *i, *o;
394 	int il, ol, l, p;
395 	struct urb *iu;
396 	struct usb_iso_packet_descriptor *id;
397 
398 	o = s->playback1st_to;
399 	ol = s->playback1st_size;
400 	l = 0;
401 
402 	if (s->insplit_pack >= 0) {
403 		iu = sk->idle_inurb;
404 		id = iu->iso_frame_desc;
405 		p = s->insplit_pack;
406 	} else
407 		goto second;
408 loop:
409 	for (; p < iu->number_of_packets && l < s->period_size; ++p) {
410 		i = iu->transfer_buffer + id[p].offset;
411 		il = id[p].actual_length;
412 		if (l + il > s->period_size)
413 			il = s->period_size - l;
414 		if (il <= ol) {
415 			memcpy(o, i, il);
416 			o += il;
417 			ol -= il;
418 		} else {
419 			memcpy(o, i, ol);
420 			singen_6pack(o, ol);
421 			o = s->playback_to;
422 			memcpy(o, i + ol, il - ol);
423 			o += il - ol;
424 			ol = s->period_size - s->playback1st_size;
425 		}
426 		l += il;
427 	}
428 	if (iu == sk->completed_inurb) {
429 		if (l != s->period_size)
430 			printk(KERN_DEBUG"%s:%i %i\n", __func__, __LINE__,
431 			       l/(int)s->cfg.frame_size);
432 
433 		return;
434 	}
435 second:
436 	iu = sk->completed_inurb;
437 	id = iu->iso_frame_desc;
438 	p = 0;
439 	goto loop;
440 
441 }
442 #else
443 static void loop_back(struct usb_stream *s)
444 {
445 }
446 #endif
447 
448 static void stream_idle(struct usb_stream_kernel *sk,
449 			struct urb *inurb, struct urb *outurb)
450 {
451 	struct usb_stream *s = sk->s;
452 	int l, p;
453 	int insize = s->idle_insize;
454 	int urb_size = 0;
455 
456 	s->inpacket_split = s->next_inpacket_split;
457 	s->inpacket_split_at = s->next_inpacket_split_at;
458 	s->next_inpacket_split = -1;
459 	s->next_inpacket_split_at = 0;
460 
461 	for (p = 0; p < inurb->number_of_packets; ++p) {
462 		struct usb_iso_packet_descriptor *id = inurb->iso_frame_desc;
463 		l = id[p].actual_length;
464 		if (unlikely(l == 0 || id[p].status)) {
465 			snd_printk(KERN_WARNING "underrun, status=%u\n",
466 				   id[p].status);
467 			goto err_out;
468 		}
469 		s->inpacket_head++;
470 		s->inpacket_head %= s->inpackets;
471 		if (s->inpacket_split == -1)
472 			s->inpacket_split = s->inpacket_head;
473 
474 		s->inpacket[s->inpacket_head].offset =
475 			id[p].offset + (inurb->transfer_buffer - (void *)s);
476 		s->inpacket[s->inpacket_head].length = l;
477 		if (insize + l > s->period_size &&
478 		    s->next_inpacket_split == -1) {
479 			s->next_inpacket_split = s->inpacket_head;
480 			s->next_inpacket_split_at = s->period_size - insize;
481 		}
482 		insize += l;
483 		urb_size += l;
484 	}
485 	s->idle_insize += urb_size - s->period_size;
486 	if (s->idle_insize < 0) {
487 		snd_printk(KERN_WARNING "%i\n",
488 			   (s->idle_insize)/(int)s->cfg.frame_size);
489 		goto err_out;
490 	}
491 	s->insize_done += urb_size;
492 
493 	l = s->idle_outsize;
494 	s->outpacket[0].offset = (sk->idle_outurb->transfer_buffer -
495 				  sk->write_page) - l;
496 
497 	if (usb_stream_prepare_playback(sk, inurb) < 0)
498 		goto err_out;
499 
500 	s->outpacket[0].length = sk->idle_outurb->transfer_buffer_length + l;
501 	s->outpacket[1].offset = sk->completed_outurb->transfer_buffer -
502 		sk->write_page;
503 
504 	if (submit_urbs(sk, inurb, outurb) < 0)
505 		goto err_out;
506 
507 	loop_back(s);
508 	s->periods_done++;
509 	wake_up_all(&sk->sleep);
510 	return;
511 err_out:
512 	s->state = usb_stream_xrun;
513 	wake_up_all(&sk->sleep);
514 }
515 
516 static void i_capture_idle(struct urb *urb)
517 {
518 	struct usb_stream_kernel *sk = urb->context;
519 	if (balance_capture(sk, urb))
520 		stream_idle(sk, urb, sk->i_urb);
521 }
522 
523 static void i_playback_idle(struct urb *urb)
524 {
525 	struct usb_stream_kernel *sk = urb->context;
526 	if (balance_playback(sk, urb))
527 		stream_idle(sk, sk->i_urb, urb);
528 }
529 
530 static void stream_start(struct usb_stream_kernel *sk,
531 			 struct urb *inurb, struct urb *outurb)
532 {
533 	struct usb_stream *s = sk->s;
534 	if (s->state >= usb_stream_sync1) {
535 		int l, p, max_diff, max_diff_0;
536 		int urb_size = 0;
537 		unsigned frames_per_packet, min_frames = 0;
538 		frames_per_packet = (s->period_size - s->idle_insize);
539 		frames_per_packet <<= 8;
540 		frames_per_packet /=
541 			s->cfg.frame_size * inurb->number_of_packets;
542 		frames_per_packet++;
543 
544 		max_diff_0 = s->cfg.frame_size;
545 		if (s->cfg.period_frames >= 256)
546 			max_diff_0 <<= 1;
547 		if (s->cfg.period_frames >= 1024)
548 			max_diff_0 <<= 1;
549 		max_diff = max_diff_0;
550 		for (p = 0; p < inurb->number_of_packets; ++p) {
551 			int diff;
552 			l = inurb->iso_frame_desc[p].actual_length;
553 			urb_size += l;
554 
555 			min_frames += frames_per_packet;
556 			diff = urb_size -
557 				(min_frames >> 8) * s->cfg.frame_size;
558 			if (diff < max_diff) {
559 				snd_printdd(KERN_DEBUG "%i %i %i %i\n",
560 					    s->insize_done,
561 					    urb_size / (int)s->cfg.frame_size,
562 					    inurb->number_of_packets, diff);
563 				max_diff = diff;
564 			}
565 		}
566 		s->idle_insize -= max_diff - max_diff_0;
567 		s->idle_insize += urb_size - s->period_size;
568 		if (s->idle_insize < 0) {
569 			snd_printk(KERN_WARNING "%i %i %i\n",
570 				   s->idle_insize, urb_size, s->period_size);
571 			return;
572 		} else if (s->idle_insize == 0) {
573 			s->next_inpacket_split =
574 				(s->inpacket_head + 1) % s->inpackets;
575 			s->next_inpacket_split_at = 0;
576 		} else {
577 			unsigned split = s->inpacket_head;
578 			l = s->idle_insize;
579 			while (l > s->inpacket[split].length) {
580 				l -= s->inpacket[split].length;
581 				if (split == 0)
582 					split = s->inpackets - 1;
583 				else
584 					split--;
585 			}
586 			s->next_inpacket_split = split;
587 			s->next_inpacket_split_at =
588 				s->inpacket[split].length - l;
589 		}
590 
591 		s->insize_done += urb_size;
592 
593 		if (usb_stream_prepare_playback(sk, inurb) < 0)
594 			return;
595 
596 	} else
597 		playback_prep_freqn(sk, sk->idle_outurb);
598 
599 	if (submit_urbs(sk, inurb, outurb) < 0)
600 		return;
601 
602 	if (s->state == usb_stream_sync1 && s->insize_done > 360000) {
603 		/* just guesswork                            ^^^^^^ */
604 		s->state = usb_stream_ready;
605 		subs_set_complete(sk->inurb, i_capture_idle);
606 		subs_set_complete(sk->outurb, i_playback_idle);
607 	}
608 }
609 
610 static void i_capture_start(struct urb *urb)
611 {
612 	struct usb_iso_packet_descriptor *id = urb->iso_frame_desc;
613 	struct usb_stream_kernel *sk = urb->context;
614 	struct usb_stream *s = sk->s;
615 	int p;
616 	int empty = 0;
617 
618 	if (urb->status) {
619 		snd_printk(KERN_WARNING "status=%i\n", urb->status);
620 		return;
621 	}
622 
623 	for (p = 0; p < urb->number_of_packets; ++p) {
624 		int l = id[p].actual_length;
625 		if (l < s->cfg.frame_size) {
626 			++empty;
627 			if (s->state >= usb_stream_sync0) {
628 				snd_printk(KERN_WARNING "%i\n", l);
629 				return;
630 			}
631 		}
632 		s->inpacket_head++;
633 		s->inpacket_head %= s->inpackets;
634 		s->inpacket[s->inpacket_head].offset =
635 			id[p].offset + (urb->transfer_buffer - (void *)s);
636 		s->inpacket[s->inpacket_head].length = l;
637 	}
638 #ifdef SHOW_EMPTY
639 	if (empty) {
640 		printk(KERN_DEBUG"%s:%i: %i", __func__, __LINE__,
641 		       urb->iso_frame_desc[0].actual_length);
642 		for (pack = 1; pack < urb->number_of_packets; ++pack) {
643 			int l = urb->iso_frame_desc[pack].actual_length;
644 			printk(KERN_CONT " %i", l);
645 		}
646 		printk(KERN_CONT "\n");
647 	}
648 #endif
649 	if (!empty && s->state < usb_stream_sync1)
650 		++s->state;
651 
652 	if (balance_capture(sk, urb))
653 		stream_start(sk, urb, sk->i_urb);
654 }
655 
656 static void i_playback_start(struct urb *urb)
657 {
658 	struct usb_stream_kernel *sk = urb->context;
659 	if (balance_playback(sk, urb))
660 		stream_start(sk, sk->i_urb, urb);
661 }
662 
663 int usb_stream_start(struct usb_stream_kernel *sk)
664 {
665 	struct usb_stream *s = sk->s;
666 	int frame = 0, iters = 0;
667 	int u, err;
668 	int try = 0;
669 
670 	if (s->state != usb_stream_stopped)
671 		return -EAGAIN;
672 
673 	subs_set_complete(sk->inurb, i_capture_start);
674 	subs_set_complete(sk->outurb, i_playback_start);
675 	memset(sk->write_page, 0, s->write_size);
676 dotry:
677 	s->insize_done = 0;
678 	s->idle_insize = 0;
679 	s->idle_outsize = 0;
680 	s->sync_packet = -1;
681 	s->inpacket_head = -1;
682 	sk->iso_frame_balance = 0;
683 	++try;
684 	for (u = 0; u < 2; u++) {
685 		struct urb *inurb = sk->inurb[u];
686 		struct urb *outurb = sk->outurb[u];
687 		playback_prep_freqn(sk, outurb);
688 		inurb->number_of_packets = outurb->number_of_packets;
689 		inurb->transfer_buffer_length =
690 			inurb->number_of_packets *
691 			inurb->iso_frame_desc[0].length;
692 
693 		if (u == 0) {
694 			int now;
695 			struct usb_device *dev = inurb->dev;
696 			frame = usb_get_current_frame_number(dev);
697 			do {
698 				now = usb_get_current_frame_number(dev);
699 				++iters;
700 			} while (now > -1 && now == frame);
701 		}
702 		err = usb_submit_urb(inurb, GFP_ATOMIC);
703 		if (err < 0) {
704 			snd_printk(KERN_ERR"usb_submit_urb(sk->inurb[%i])"
705 				   " returned %i\n", u, err);
706 			return err;
707 		}
708 		err = usb_submit_urb(outurb, GFP_ATOMIC);
709 		if (err < 0) {
710 			snd_printk(KERN_ERR"usb_submit_urb(sk->outurb[%i])"
711 				   " returned %i\n", u, err);
712 			return err;
713 		}
714 
715 		if (inurb->start_frame != outurb->start_frame) {
716 			snd_printd(KERN_DEBUG
717 				   "u[%i] start_frames differ in:%u out:%u\n",
718 				   u, inurb->start_frame, outurb->start_frame);
719 			goto check_retry;
720 		}
721 	}
722 	snd_printdd(KERN_DEBUG "%i %i\n", frame, iters);
723 	try = 0;
724 check_retry:
725 	if (try) {
726 		usb_stream_stop(sk);
727 		if (try < 5) {
728 			msleep(1500);
729 			snd_printd(KERN_DEBUG "goto dotry;\n");
730 			goto dotry;
731 		}
732 		snd_printk(KERN_WARNING"couldn't start"
733 			   " all urbs on the same start_frame.\n");
734 		return -EFAULT;
735 	}
736 
737 	sk->idle_inurb = sk->inurb[USB_STREAM_NURBS - 2];
738 	sk->idle_outurb = sk->outurb[USB_STREAM_NURBS - 2];
739 	sk->completed_inurb = sk->inurb[USB_STREAM_NURBS - 1];
740 	sk->completed_outurb = sk->outurb[USB_STREAM_NURBS - 1];
741 
742 /* wait, check */
743 	{
744 		int wait_ms = 3000;
745 		while (s->state != usb_stream_ready && wait_ms > 0) {
746 			snd_printdd(KERN_DEBUG "%i\n", s->state);
747 			msleep(200);
748 			wait_ms -= 200;
749 		}
750 	}
751 
752 	return s->state == usb_stream_ready ? 0 : -EFAULT;
753 }
754 
755 
756 /*                             stop                                   */
757 
758 void usb_stream_stop(struct usb_stream_kernel *sk)
759 {
760 	int u;
761 	if (!sk->s)
762 		return;
763 	for (u = 0; u < USB_STREAM_NURBS; ++u) {
764 		usb_kill_urb(sk->inurb[u]);
765 		usb_kill_urb(sk->outurb[u]);
766 	}
767 	sk->s->state = usb_stream_stopped;
768 	msleep(400);
769 }
770