xref: /linux/sound/core/timer.c (revision 6e8331ac6973435b1e7604c30f2ad394035b46e1)
1 /*
2  *  Timers abstract layer
3  *  Copyright (c) by Jaroslav Kysela <perex@suse.cz>
4  *
5  *
6  *   This program is free software; you can redistribute it and/or modify
7  *   it under the terms of the GNU General Public License as published by
8  *   the Free Software Foundation; either version 2 of the License, or
9  *   (at your option) any later version.
10  *
11  *   This program is distributed in the hope that it will be useful,
12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  *   GNU General Public License for more details.
15  *
16  *   You should have received a copy of the GNU General Public License
17  *   along with this program; if not, write to the Free Software
18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19  *
20  */
21 
22 #include <sound/driver.h>
23 #include <linux/delay.h>
24 #include <linux/init.h>
25 #include <linux/smp_lock.h>
26 #include <linux/slab.h>
27 #include <linux/time.h>
28 #include <linux/mutex.h>
29 #include <linux/moduleparam.h>
30 #include <linux/string.h>
31 #include <sound/core.h>
32 #include <sound/timer.h>
33 #include <sound/control.h>
34 #include <sound/info.h>
35 #include <sound/minors.h>
36 #include <sound/initval.h>
37 #include <linux/kmod.h>
38 #ifdef CONFIG_KERNELD
39 #include <linux/kerneld.h>
40 #endif
41 
42 #if defined(CONFIG_SND_HPET) || defined(CONFIG_SND_HPET_MODULE)
43 #define DEFAULT_TIMER_LIMIT 3
44 #elif defined(CONFIG_SND_RTCTIMER) || defined(CONFIG_SND_RTCTIMER_MODULE)
45 #define DEFAULT_TIMER_LIMIT 2
46 #else
47 #define DEFAULT_TIMER_LIMIT 1
48 #endif
49 
50 static int timer_limit = DEFAULT_TIMER_LIMIT;
51 MODULE_AUTHOR("Jaroslav Kysela <perex@suse.cz>, Takashi Iwai <tiwai@suse.de>");
52 MODULE_DESCRIPTION("ALSA timer interface");
53 MODULE_LICENSE("GPL");
54 module_param(timer_limit, int, 0444);
55 MODULE_PARM_DESC(timer_limit, "Maximum global timers in system.");
56 
57 struct snd_timer_user {
58 	struct snd_timer_instance *timeri;
59 	int tread;		/* enhanced read with timestamps and events */
60 	unsigned long ticks;
61 	unsigned long overrun;
62 	int qhead;
63 	int qtail;
64 	int qused;
65 	int queue_size;
66 	struct snd_timer_read *queue;
67 	struct snd_timer_tread *tqueue;
68 	spinlock_t qlock;
69 	unsigned long last_resolution;
70 	unsigned int filter;
71 	struct timespec tstamp;		/* trigger tstamp */
72 	wait_queue_head_t qchange_sleep;
73 	struct fasync_struct *fasync;
74 	struct mutex tread_sem;
75 };
76 
77 /* list of timers */
78 static LIST_HEAD(snd_timer_list);
79 
80 /* list of slave instances */
81 static LIST_HEAD(snd_timer_slave_list);
82 
83 /* lock for slave active lists */
84 static DEFINE_SPINLOCK(slave_active_lock);
85 
86 static DEFINE_MUTEX(register_mutex);
87 
88 static int snd_timer_free(struct snd_timer *timer);
89 static int snd_timer_dev_free(struct snd_device *device);
90 static int snd_timer_dev_register(struct snd_device *device);
91 static int snd_timer_dev_unregister(struct snd_device *device);
92 
93 static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left);
94 
95 /*
96  * create a timer instance with the given owner string.
97  * when timer is not NULL, increments the module counter
98  */
99 static struct snd_timer_instance *snd_timer_instance_new(char *owner,
100 							 struct snd_timer *timer)
101 {
102 	struct snd_timer_instance *timeri;
103 	timeri = kzalloc(sizeof(*timeri), GFP_KERNEL);
104 	if (timeri == NULL)
105 		return NULL;
106 	timeri->owner = kstrdup(owner, GFP_KERNEL);
107 	if (! timeri->owner) {
108 		kfree(timeri);
109 		return NULL;
110 	}
111 	INIT_LIST_HEAD(&timeri->open_list);
112 	INIT_LIST_HEAD(&timeri->active_list);
113 	INIT_LIST_HEAD(&timeri->ack_list);
114 	INIT_LIST_HEAD(&timeri->slave_list_head);
115 	INIT_LIST_HEAD(&timeri->slave_active_head);
116 
117 	timeri->timer = timer;
118 	if (timer && !try_module_get(timer->module)) {
119 		kfree(timeri->owner);
120 		kfree(timeri);
121 		return NULL;
122 	}
123 
124 	return timeri;
125 }
126 
127 /*
128  * find a timer instance from the given timer id
129  */
130 static struct snd_timer *snd_timer_find(struct snd_timer_id *tid)
131 {
132 	struct snd_timer *timer = NULL;
133 	struct list_head *p;
134 
135 	list_for_each(p, &snd_timer_list) {
136 		timer = list_entry(p, struct snd_timer, device_list);
137 
138 		if (timer->tmr_class != tid->dev_class)
139 			continue;
140 		if ((timer->tmr_class == SNDRV_TIMER_CLASS_CARD ||
141 		     timer->tmr_class == SNDRV_TIMER_CLASS_PCM) &&
142 		    (timer->card == NULL ||
143 		     timer->card->number != tid->card))
144 			continue;
145 		if (timer->tmr_device != tid->device)
146 			continue;
147 		if (timer->tmr_subdevice != tid->subdevice)
148 			continue;
149 		return timer;
150 	}
151 	return NULL;
152 }
153 
154 #ifdef CONFIG_KMOD
155 
156 static void snd_timer_request(struct snd_timer_id *tid)
157 {
158 	if (! current->fs->root)
159 		return;
160 	switch (tid->dev_class) {
161 	case SNDRV_TIMER_CLASS_GLOBAL:
162 		if (tid->device < timer_limit)
163 			request_module("snd-timer-%i", tid->device);
164 		break;
165 	case SNDRV_TIMER_CLASS_CARD:
166 	case SNDRV_TIMER_CLASS_PCM:
167 		if (tid->card < snd_ecards_limit)
168 			request_module("snd-card-%i", tid->card);
169 		break;
170 	default:
171 		break;
172 	}
173 }
174 
175 #endif
176 
177 /*
178  * look for a master instance matching with the slave id of the given slave.
179  * when found, relink the open_link of the slave.
180  *
181  * call this with register_mutex down.
182  */
183 static void snd_timer_check_slave(struct snd_timer_instance *slave)
184 {
185 	struct snd_timer *timer;
186 	struct snd_timer_instance *master;
187 	struct list_head *p, *q;
188 
189 	/* FIXME: it's really dumb to look up all entries.. */
190 	list_for_each(p, &snd_timer_list) {
191 		timer = list_entry(p, struct snd_timer, device_list);
192 		list_for_each(q, &timer->open_list_head) {
193 			master = list_entry(q, struct snd_timer_instance, open_list);
194 			if (slave->slave_class == master->slave_class &&
195 			    slave->slave_id == master->slave_id) {
196 				list_del(&slave->open_list);
197 				list_add_tail(&slave->open_list,
198 					      &master->slave_list_head);
199 				spin_lock_irq(&slave_active_lock);
200 				slave->master = master;
201 				slave->timer = master->timer;
202 				spin_unlock_irq(&slave_active_lock);
203 				return;
204 			}
205 		}
206 	}
207 }
208 
209 /*
210  * look for slave instances matching with the slave id of the given master.
211  * when found, relink the open_link of slaves.
212  *
213  * call this with register_mutex down.
214  */
215 static void snd_timer_check_master(struct snd_timer_instance *master)
216 {
217 	struct snd_timer_instance *slave;
218 	struct list_head *p, *n;
219 
220 	/* check all pending slaves */
221 	list_for_each_safe(p, n, &snd_timer_slave_list) {
222 		slave = list_entry(p, struct snd_timer_instance, open_list);
223 		if (slave->slave_class == master->slave_class &&
224 		    slave->slave_id == master->slave_id) {
225 			list_del(p);
226 			list_add_tail(p, &master->slave_list_head);
227 			spin_lock_irq(&slave_active_lock);
228 			slave->master = master;
229 			slave->timer = master->timer;
230 			if (slave->flags & SNDRV_TIMER_IFLG_RUNNING)
231 				list_add_tail(&slave->active_list,
232 					      &master->slave_active_head);
233 			spin_unlock_irq(&slave_active_lock);
234 		}
235 	}
236 }
237 
238 /*
239  * open a timer instance
240  * when opening a master, the slave id must be here given.
241  */
242 int snd_timer_open(struct snd_timer_instance **ti,
243 		   char *owner, struct snd_timer_id *tid,
244 		   unsigned int slave_id)
245 {
246 	struct snd_timer *timer;
247 	struct snd_timer_instance *timeri = NULL;
248 
249 	if (tid->dev_class == SNDRV_TIMER_CLASS_SLAVE) {
250 		/* open a slave instance */
251 		if (tid->dev_sclass <= SNDRV_TIMER_SCLASS_NONE ||
252 		    tid->dev_sclass > SNDRV_TIMER_SCLASS_OSS_SEQUENCER) {
253 			snd_printd("invalid slave class %i\n", tid->dev_sclass);
254 			return -EINVAL;
255 		}
256 		mutex_lock(&register_mutex);
257 		timeri = snd_timer_instance_new(owner, NULL);
258 		if (!timeri) {
259 			mutex_unlock(&register_mutex);
260 			return -ENOMEM;
261 		}
262 		timeri->slave_class = tid->dev_sclass;
263 		timeri->slave_id = tid->device;
264 		timeri->flags |= SNDRV_TIMER_IFLG_SLAVE;
265 		list_add_tail(&timeri->open_list, &snd_timer_slave_list);
266 		snd_timer_check_slave(timeri);
267 		mutex_unlock(&register_mutex);
268 		*ti = timeri;
269 		return 0;
270 	}
271 
272 	/* open a master instance */
273 	mutex_lock(&register_mutex);
274 	timer = snd_timer_find(tid);
275 #ifdef CONFIG_KMOD
276 	if (timer == NULL) {
277 		mutex_unlock(&register_mutex);
278 		snd_timer_request(tid);
279 		mutex_lock(&register_mutex);
280 		timer = snd_timer_find(tid);
281 	}
282 #endif
283 	if (!timer) {
284 		mutex_unlock(&register_mutex);
285 		return -ENODEV;
286 	}
287 	if (!list_empty(&timer->open_list_head)) {
288 		timeri = list_entry(timer->open_list_head.next,
289 				    struct snd_timer_instance, open_list);
290 		if (timeri->flags & SNDRV_TIMER_IFLG_EXCLUSIVE) {
291 			mutex_unlock(&register_mutex);
292 			return -EBUSY;
293 		}
294 	}
295 	timeri = snd_timer_instance_new(owner, timer);
296 	if (!timeri) {
297 		mutex_unlock(&register_mutex);
298 		return -ENOMEM;
299 	}
300 	timeri->slave_class = tid->dev_sclass;
301 	timeri->slave_id = slave_id;
302 	if (list_empty(&timer->open_list_head) && timer->hw.open)
303 		timer->hw.open(timer);
304 	list_add_tail(&timeri->open_list, &timer->open_list_head);
305 	snd_timer_check_master(timeri);
306 	mutex_unlock(&register_mutex);
307 	*ti = timeri;
308 	return 0;
309 }
310 
311 static int _snd_timer_stop(struct snd_timer_instance *timeri,
312 			   int keep_flag, int event);
313 
314 /*
315  * close a timer instance
316  */
317 int snd_timer_close(struct snd_timer_instance *timeri)
318 {
319 	struct snd_timer *timer = NULL;
320 	struct list_head *p, *n;
321 	struct snd_timer_instance *slave;
322 
323 	snd_assert(timeri != NULL, return -ENXIO);
324 
325 	/* force to stop the timer */
326 	snd_timer_stop(timeri);
327 
328 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) {
329 		/* wait, until the active callback is finished */
330 		spin_lock_irq(&slave_active_lock);
331 		while (timeri->flags & SNDRV_TIMER_IFLG_CALLBACK) {
332 			spin_unlock_irq(&slave_active_lock);
333 			udelay(10);
334 			spin_lock_irq(&slave_active_lock);
335 		}
336 		spin_unlock_irq(&slave_active_lock);
337 		mutex_lock(&register_mutex);
338 		list_del(&timeri->open_list);
339 		mutex_unlock(&register_mutex);
340 	} else {
341 		timer = timeri->timer;
342 		/* wait, until the active callback is finished */
343 		spin_lock_irq(&timer->lock);
344 		while (timeri->flags & SNDRV_TIMER_IFLG_CALLBACK) {
345 			spin_unlock_irq(&timer->lock);
346 			udelay(10);
347 			spin_lock_irq(&timer->lock);
348 		}
349 		spin_unlock_irq(&timer->lock);
350 		mutex_lock(&register_mutex);
351 		list_del(&timeri->open_list);
352 		if (timer && list_empty(&timer->open_list_head) &&
353 		    timer->hw.close)
354 			timer->hw.close(timer);
355 		/* remove slave links */
356 		list_for_each_safe(p, n, &timeri->slave_list_head) {
357 			slave = list_entry(p, struct snd_timer_instance, open_list);
358 			spin_lock_irq(&slave_active_lock);
359 			_snd_timer_stop(slave, 1, SNDRV_TIMER_EVENT_RESOLUTION);
360 			list_del(p);
361 			list_add_tail(p, &snd_timer_slave_list);
362 			slave->master = NULL;
363 			slave->timer = NULL;
364 			spin_unlock_irq(&slave_active_lock);
365 		}
366 		mutex_unlock(&register_mutex);
367 	}
368 	if (timeri->private_free)
369 		timeri->private_free(timeri);
370 	kfree(timeri->owner);
371 	kfree(timeri);
372 	if (timer)
373 		module_put(timer->module);
374 	return 0;
375 }
376 
377 unsigned long snd_timer_resolution(struct snd_timer_instance *timeri)
378 {
379 	struct snd_timer * timer;
380 
381 	if (timeri == NULL)
382 		return 0;
383 	if ((timer = timeri->timer) != NULL) {
384 		if (timer->hw.c_resolution)
385 			return timer->hw.c_resolution(timer);
386 		return timer->hw.resolution;
387 	}
388 	return 0;
389 }
390 
391 static void snd_timer_notify1(struct snd_timer_instance *ti, int event)
392 {
393 	struct snd_timer *timer;
394 	unsigned long flags;
395 	unsigned long resolution = 0;
396 	struct snd_timer_instance *ts;
397 	struct list_head *n;
398 	struct timespec tstamp;
399 
400 	getnstimeofday(&tstamp);
401 	snd_assert(event >= SNDRV_TIMER_EVENT_START &&
402 		   event <= SNDRV_TIMER_EVENT_PAUSE, return);
403 	if (event == SNDRV_TIMER_EVENT_START ||
404 	    event == SNDRV_TIMER_EVENT_CONTINUE)
405 		resolution = snd_timer_resolution(ti);
406 	if (ti->ccallback)
407 		ti->ccallback(ti, SNDRV_TIMER_EVENT_START, &tstamp, resolution);
408 	if (ti->flags & SNDRV_TIMER_IFLG_SLAVE)
409 		return;
410 	timer = ti->timer;
411 	if (timer == NULL)
412 		return;
413 	if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
414 		return;
415 	spin_lock_irqsave(&timer->lock, flags);
416 	list_for_each(n, &ti->slave_active_head) {
417 		ts = list_entry(n, struct snd_timer_instance, active_list);
418 		if (ts->ccallback)
419 			ts->ccallback(ti, event + 100, &tstamp, resolution);
420 	}
421 	spin_unlock_irqrestore(&timer->lock, flags);
422 }
423 
424 static int snd_timer_start1(struct snd_timer *timer, struct snd_timer_instance *timeri,
425 			    unsigned long sticks)
426 {
427 	list_del(&timeri->active_list);
428 	list_add_tail(&timeri->active_list, &timer->active_list_head);
429 	if (timer->running) {
430 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
431 			goto __start_now;
432 		timer->flags |= SNDRV_TIMER_FLG_RESCHED;
433 		timeri->flags |= SNDRV_TIMER_IFLG_START;
434 		return 1;	/* delayed start */
435 	} else {
436 		timer->sticks = sticks;
437 		timer->hw.start(timer);
438 	      __start_now:
439 		timer->running++;
440 		timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
441 		return 0;
442 	}
443 }
444 
445 static int snd_timer_start_slave(struct snd_timer_instance *timeri)
446 {
447 	unsigned long flags;
448 
449 	spin_lock_irqsave(&slave_active_lock, flags);
450 	timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
451 	if (timeri->master)
452 		list_add_tail(&timeri->active_list,
453 			      &timeri->master->slave_active_head);
454 	spin_unlock_irqrestore(&slave_active_lock, flags);
455 	return 1; /* delayed start */
456 }
457 
458 /*
459  *  start the timer instance
460  */
461 int snd_timer_start(struct snd_timer_instance *timeri, unsigned int ticks)
462 {
463 	struct snd_timer *timer;
464 	int result = -EINVAL;
465 	unsigned long flags;
466 
467 	if (timeri == NULL || ticks < 1)
468 		return -EINVAL;
469 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) {
470 		result = snd_timer_start_slave(timeri);
471 		snd_timer_notify1(timeri, SNDRV_TIMER_EVENT_START);
472 		return result;
473 	}
474 	timer = timeri->timer;
475 	if (timer == NULL)
476 		return -EINVAL;
477 	spin_lock_irqsave(&timer->lock, flags);
478 	timeri->ticks = timeri->cticks = ticks;
479 	timeri->pticks = 0;
480 	result = snd_timer_start1(timer, timeri, ticks);
481 	spin_unlock_irqrestore(&timer->lock, flags);
482 	snd_timer_notify1(timeri, SNDRV_TIMER_EVENT_START);
483 	return result;
484 }
485 
486 static int _snd_timer_stop(struct snd_timer_instance * timeri,
487 			   int keep_flag, int event)
488 {
489 	struct snd_timer *timer;
490 	unsigned long flags;
491 
492 	snd_assert(timeri != NULL, return -ENXIO);
493 
494 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) {
495 		if (!keep_flag) {
496 			spin_lock_irqsave(&slave_active_lock, flags);
497 			timeri->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
498 			spin_unlock_irqrestore(&slave_active_lock, flags);
499 		}
500 		goto __end;
501 	}
502 	timer = timeri->timer;
503 	if (!timer)
504 		return -EINVAL;
505 	spin_lock_irqsave(&timer->lock, flags);
506 	list_del_init(&timeri->ack_list);
507 	list_del_init(&timeri->active_list);
508 	if ((timeri->flags & SNDRV_TIMER_IFLG_RUNNING) &&
509 	    !(--timer->running)) {
510 		timer->hw.stop(timer);
511 		if (timer->flags & SNDRV_TIMER_FLG_RESCHED) {
512 			timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
513 			snd_timer_reschedule(timer, 0);
514 			if (timer->flags & SNDRV_TIMER_FLG_CHANGE) {
515 				timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
516 				timer->hw.start(timer);
517 			}
518 		}
519 	}
520 	if (!keep_flag)
521 		timeri->flags &=
522 			~(SNDRV_TIMER_IFLG_RUNNING | SNDRV_TIMER_IFLG_START);
523 	spin_unlock_irqrestore(&timer->lock, flags);
524       __end:
525 	if (event != SNDRV_TIMER_EVENT_RESOLUTION)
526 		snd_timer_notify1(timeri, event);
527 	return 0;
528 }
529 
530 /*
531  * stop the timer instance.
532  *
533  * do not call this from the timer callback!
534  */
535 int snd_timer_stop(struct snd_timer_instance *timeri)
536 {
537 	struct snd_timer *timer;
538 	unsigned long flags;
539 	int err;
540 
541 	err = _snd_timer_stop(timeri, 0, SNDRV_TIMER_EVENT_STOP);
542 	if (err < 0)
543 		return err;
544 	timer = timeri->timer;
545 	spin_lock_irqsave(&timer->lock, flags);
546 	timeri->cticks = timeri->ticks;
547 	timeri->pticks = 0;
548 	spin_unlock_irqrestore(&timer->lock, flags);
549 	return 0;
550 }
551 
552 /*
553  * start again..  the tick is kept.
554  */
555 int snd_timer_continue(struct snd_timer_instance *timeri)
556 {
557 	struct snd_timer *timer;
558 	int result = -EINVAL;
559 	unsigned long flags;
560 
561 	if (timeri == NULL)
562 		return result;
563 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
564 		return snd_timer_start_slave(timeri);
565 	timer = timeri->timer;
566 	if (! timer)
567 		return -EINVAL;
568 	spin_lock_irqsave(&timer->lock, flags);
569 	if (!timeri->cticks)
570 		timeri->cticks = 1;
571 	timeri->pticks = 0;
572 	result = snd_timer_start1(timer, timeri, timer->sticks);
573 	spin_unlock_irqrestore(&timer->lock, flags);
574 	snd_timer_notify1(timeri, SNDRV_TIMER_EVENT_CONTINUE);
575 	return result;
576 }
577 
578 /*
579  * pause.. remember the ticks left
580  */
581 int snd_timer_pause(struct snd_timer_instance * timeri)
582 {
583 	return _snd_timer_stop(timeri, 0, SNDRV_TIMER_EVENT_PAUSE);
584 }
585 
586 /*
587  * reschedule the timer
588  *
589  * start pending instances and check the scheduling ticks.
590  * when the scheduling ticks is changed set CHANGE flag to reprogram the timer.
591  */
592 static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left)
593 {
594 	struct snd_timer_instance *ti;
595 	unsigned long ticks = ~0UL;
596 	struct list_head *p;
597 
598 	list_for_each(p, &timer->active_list_head) {
599 		ti = list_entry(p, struct snd_timer_instance, active_list);
600 		if (ti->flags & SNDRV_TIMER_IFLG_START) {
601 			ti->flags &= ~SNDRV_TIMER_IFLG_START;
602 			ti->flags |= SNDRV_TIMER_IFLG_RUNNING;
603 			timer->running++;
604 		}
605 		if (ti->flags & SNDRV_TIMER_IFLG_RUNNING) {
606 			if (ticks > ti->cticks)
607 				ticks = ti->cticks;
608 		}
609 	}
610 	if (ticks == ~0UL) {
611 		timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
612 		return;
613 	}
614 	if (ticks > timer->hw.ticks)
615 		ticks = timer->hw.ticks;
616 	if (ticks_left != ticks)
617 		timer->flags |= SNDRV_TIMER_FLG_CHANGE;
618 	timer->sticks = ticks;
619 }
620 
621 /*
622  * timer tasklet
623  *
624  */
625 static void snd_timer_tasklet(unsigned long arg)
626 {
627 	struct snd_timer *timer = (struct snd_timer *) arg;
628 	struct snd_timer_instance *ti;
629 	struct list_head *p;
630 	unsigned long resolution, ticks;
631 	unsigned long flags;
632 
633 	spin_lock_irqsave(&timer->lock, flags);
634 	/* now process all callbacks */
635 	while (!list_empty(&timer->sack_list_head)) {
636 		p = timer->sack_list_head.next;		/* get first item */
637 		ti = list_entry(p, struct snd_timer_instance, ack_list);
638 
639 		/* remove from ack_list and make empty */
640 		list_del_init(p);
641 
642 		ticks = ti->pticks;
643 		ti->pticks = 0;
644 		resolution = ti->resolution;
645 
646 		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
647 		spin_unlock(&timer->lock);
648 		if (ti->callback)
649 			ti->callback(ti, resolution, ticks);
650 		spin_lock(&timer->lock);
651 		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
652 	}
653 	spin_unlock_irqrestore(&timer->lock, flags);
654 }
655 
656 /*
657  * timer interrupt
658  *
659  * ticks_left is usually equal to timer->sticks.
660  *
661  */
662 void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
663 {
664 	struct snd_timer_instance *ti, *ts;
665 	unsigned long resolution, ticks;
666 	struct list_head *p, *q, *n, *ack_list_head;
667 	unsigned long flags;
668 	int use_tasklet = 0;
669 
670 	if (timer == NULL)
671 		return;
672 
673 	spin_lock_irqsave(&timer->lock, flags);
674 
675 	/* remember the current resolution */
676 	if (timer->hw.c_resolution)
677 		resolution = timer->hw.c_resolution(timer);
678 	else
679 		resolution = timer->hw.resolution;
680 
681 	/* loop for all active instances
682 	 * Here we cannot use list_for_each because the active_list of a
683 	 * processed instance is relinked to done_list_head before the callback
684 	 * is called.
685 	 */
686 	list_for_each_safe(p, n, &timer->active_list_head) {
687 		ti = list_entry(p, struct snd_timer_instance, active_list);
688 		if (!(ti->flags & SNDRV_TIMER_IFLG_RUNNING))
689 			continue;
690 		ti->pticks += ticks_left;
691 		ti->resolution = resolution;
692 		if (ti->cticks < ticks_left)
693 			ti->cticks = 0;
694 		else
695 			ti->cticks -= ticks_left;
696 		if (ti->cticks) /* not expired */
697 			continue;
698 		if (ti->flags & SNDRV_TIMER_IFLG_AUTO) {
699 			ti->cticks = ti->ticks;
700 		} else {
701 			ti->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
702 			if (--timer->running)
703 				list_del(p);
704 		}
705 		if ((timer->hw.flags & SNDRV_TIMER_HW_TASKLET) ||
706 		    (ti->flags & SNDRV_TIMER_IFLG_FAST))
707 			ack_list_head = &timer->ack_list_head;
708 		else
709 			ack_list_head = &timer->sack_list_head;
710 		if (list_empty(&ti->ack_list))
711 			list_add_tail(&ti->ack_list, ack_list_head);
712 		list_for_each(q, &ti->slave_active_head) {
713 			ts = list_entry(q, struct snd_timer_instance, active_list);
714 			ts->pticks = ti->pticks;
715 			ts->resolution = resolution;
716 			if (list_empty(&ts->ack_list))
717 				list_add_tail(&ts->ack_list, ack_list_head);
718 		}
719 	}
720 	if (timer->flags & SNDRV_TIMER_FLG_RESCHED)
721 		snd_timer_reschedule(timer, ticks_left);
722 	if (timer->running) {
723 		if (timer->hw.flags & SNDRV_TIMER_HW_STOP) {
724 			timer->hw.stop(timer);
725 			timer->flags |= SNDRV_TIMER_FLG_CHANGE;
726 		}
727 		if (!(timer->hw.flags & SNDRV_TIMER_HW_AUTO) ||
728 		    (timer->flags & SNDRV_TIMER_FLG_CHANGE)) {
729 			/* restart timer */
730 			timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
731 			timer->hw.start(timer);
732 		}
733 	} else {
734 		timer->hw.stop(timer);
735 	}
736 
737 	/* now process all fast callbacks */
738 	while (!list_empty(&timer->ack_list_head)) {
739 		p = timer->ack_list_head.next;		/* get first item */
740 		ti = list_entry(p, struct snd_timer_instance, ack_list);
741 
742 		/* remove from ack_list and make empty */
743 		list_del_init(p);
744 
745 		ticks = ti->pticks;
746 		ti->pticks = 0;
747 
748 		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
749 		spin_unlock(&timer->lock);
750 		if (ti->callback)
751 			ti->callback(ti, resolution, ticks);
752 		spin_lock(&timer->lock);
753 		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
754 	}
755 
756 	/* do we have any slow callbacks? */
757 	use_tasklet = !list_empty(&timer->sack_list_head);
758 	spin_unlock_irqrestore(&timer->lock, flags);
759 
760 	if (use_tasklet)
761 		tasklet_hi_schedule(&timer->task_queue);
762 }
763 
764 /*
765 
766  */
767 
768 int snd_timer_new(struct snd_card *card, char *id, struct snd_timer_id *tid,
769 		  struct snd_timer **rtimer)
770 {
771 	struct snd_timer *timer;
772 	int err;
773 	static struct snd_device_ops ops = {
774 		.dev_free = snd_timer_dev_free,
775 		.dev_register = snd_timer_dev_register,
776 		.dev_unregister = snd_timer_dev_unregister
777 	};
778 
779 	snd_assert(tid != NULL, return -EINVAL);
780 	snd_assert(rtimer != NULL, return -EINVAL);
781 	*rtimer = NULL;
782 	timer = kzalloc(sizeof(*timer), GFP_KERNEL);
783 	if (timer == NULL) {
784 		snd_printk(KERN_ERR "timer: cannot allocate\n");
785 		return -ENOMEM;
786 	}
787 	timer->tmr_class = tid->dev_class;
788 	timer->card = card;
789 	timer->tmr_device = tid->device;
790 	timer->tmr_subdevice = tid->subdevice;
791 	if (id)
792 		strlcpy(timer->id, id, sizeof(timer->id));
793 	INIT_LIST_HEAD(&timer->device_list);
794 	INIT_LIST_HEAD(&timer->open_list_head);
795 	INIT_LIST_HEAD(&timer->active_list_head);
796 	INIT_LIST_HEAD(&timer->ack_list_head);
797 	INIT_LIST_HEAD(&timer->sack_list_head);
798 	spin_lock_init(&timer->lock);
799 	tasklet_init(&timer->task_queue, snd_timer_tasklet,
800 		     (unsigned long)timer);
801 	if (card != NULL) {
802 		timer->module = card->module;
803 		err = snd_device_new(card, SNDRV_DEV_TIMER, timer, &ops);
804 		if (err < 0) {
805 			snd_timer_free(timer);
806 			return err;
807 		}
808 	}
809 	*rtimer = timer;
810 	return 0;
811 }
812 
813 static int snd_timer_free(struct snd_timer *timer)
814 {
815 	snd_assert(timer != NULL, return -ENXIO);
816 	if (timer->private_free)
817 		timer->private_free(timer);
818 	kfree(timer);
819 	return 0;
820 }
821 
822 static int snd_timer_dev_free(struct snd_device *device)
823 {
824 	struct snd_timer *timer = device->device_data;
825 	return snd_timer_free(timer);
826 }
827 
828 static int snd_timer_dev_register(struct snd_device *dev)
829 {
830 	struct snd_timer *timer = dev->device_data;
831 	struct snd_timer *timer1;
832 	struct list_head *p;
833 
834 	snd_assert(timer != NULL && timer->hw.start != NULL &&
835 		   timer->hw.stop != NULL, return -ENXIO);
836 	if (!(timer->hw.flags & SNDRV_TIMER_HW_SLAVE) &&
837 	    !timer->hw.resolution && timer->hw.c_resolution == NULL)
838 	    	return -EINVAL;
839 
840 	mutex_lock(&register_mutex);
841 	list_for_each(p, &snd_timer_list) {
842 		timer1 = list_entry(p, struct snd_timer, device_list);
843 		if (timer1->tmr_class > timer->tmr_class)
844 			break;
845 		if (timer1->tmr_class < timer->tmr_class)
846 			continue;
847 		if (timer1->card && timer->card) {
848 			if (timer1->card->number > timer->card->number)
849 				break;
850 			if (timer1->card->number < timer->card->number)
851 				continue;
852 		}
853 		if (timer1->tmr_device > timer->tmr_device)
854 			break;
855 		if (timer1->tmr_device < timer->tmr_device)
856 			continue;
857 		if (timer1->tmr_subdevice > timer->tmr_subdevice)
858 			break;
859 		if (timer1->tmr_subdevice < timer->tmr_subdevice)
860 			continue;
861 		/* conflicts.. */
862 		mutex_unlock(&register_mutex);
863 		return -EBUSY;
864 	}
865 	list_add_tail(&timer->device_list, p);
866 	mutex_unlock(&register_mutex);
867 	return 0;
868 }
869 
870 static int snd_timer_unregister(struct snd_timer *timer)
871 {
872 	struct list_head *p, *n;
873 	struct snd_timer_instance *ti;
874 
875 	snd_assert(timer != NULL, return -ENXIO);
876 	mutex_lock(&register_mutex);
877 	if (! list_empty(&timer->open_list_head)) {
878 		snd_printk(KERN_WARNING "timer 0x%lx is busy?\n", (long)timer);
879 		list_for_each_safe(p, n, &timer->open_list_head) {
880 			list_del_init(p);
881 			ti = list_entry(p, struct snd_timer_instance, open_list);
882 			ti->timer = NULL;
883 		}
884 	}
885 	list_del(&timer->device_list);
886 	mutex_unlock(&register_mutex);
887 	return snd_timer_free(timer);
888 }
889 
890 static int snd_timer_dev_unregister(struct snd_device *device)
891 {
892 	struct snd_timer *timer = device->device_data;
893 	return snd_timer_unregister(timer);
894 }
895 
896 void snd_timer_notify(struct snd_timer *timer, int event, struct timespec *tstamp)
897 {
898 	unsigned long flags;
899 	unsigned long resolution = 0;
900 	struct snd_timer_instance *ti, *ts;
901 	struct list_head *p, *n;
902 
903 	if (! (timer->hw.flags & SNDRV_TIMER_HW_SLAVE))
904 		return;
905 	snd_assert(event >= SNDRV_TIMER_EVENT_MSTART &&
906 		   event <= SNDRV_TIMER_EVENT_MRESUME, return);
907 	spin_lock_irqsave(&timer->lock, flags);
908 	if (event == SNDRV_TIMER_EVENT_MSTART ||
909 	    event == SNDRV_TIMER_EVENT_MCONTINUE ||
910 	    event == SNDRV_TIMER_EVENT_MRESUME) {
911 		if (timer->hw.c_resolution)
912 			resolution = timer->hw.c_resolution(timer);
913 		else
914 			resolution = timer->hw.resolution;
915 	}
916 	list_for_each(p, &timer->active_list_head) {
917 		ti = list_entry(p, struct snd_timer_instance, active_list);
918 		if (ti->ccallback)
919 			ti->ccallback(ti, event, tstamp, resolution);
920 		list_for_each(n, &ti->slave_active_head) {
921 			ts = list_entry(n, struct snd_timer_instance, active_list);
922 			if (ts->ccallback)
923 				ts->ccallback(ts, event, tstamp, resolution);
924 		}
925 	}
926 	spin_unlock_irqrestore(&timer->lock, flags);
927 }
928 
929 /*
930  * exported functions for global timers
931  */
932 int snd_timer_global_new(char *id, int device, struct snd_timer **rtimer)
933 {
934 	struct snd_timer_id tid;
935 
936 	tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
937 	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
938 	tid.card = -1;
939 	tid.device = device;
940 	tid.subdevice = 0;
941 	return snd_timer_new(NULL, id, &tid, rtimer);
942 }
943 
944 int snd_timer_global_free(struct snd_timer *timer)
945 {
946 	return snd_timer_free(timer);
947 }
948 
949 int snd_timer_global_register(struct snd_timer *timer)
950 {
951 	struct snd_device dev;
952 
953 	memset(&dev, 0, sizeof(dev));
954 	dev.device_data = timer;
955 	return snd_timer_dev_register(&dev);
956 }
957 
958 int snd_timer_global_unregister(struct snd_timer *timer)
959 {
960 	return snd_timer_unregister(timer);
961 }
962 
963 /*
964  *  System timer
965  */
966 
967 struct snd_timer_system_private {
968 	struct timer_list tlist;
969 	struct timer * timer;
970 	unsigned long last_expires;
971 	unsigned long last_jiffies;
972 	unsigned long correction;
973 };
974 
975 static void snd_timer_s_function(unsigned long data)
976 {
977 	struct snd_timer *timer = (struct snd_timer *)data;
978 	struct snd_timer_system_private *priv = timer->private_data;
979 	unsigned long jiff = jiffies;
980 	if (time_after(jiff, priv->last_expires))
981 		priv->correction = (long)jiff - (long)priv->last_expires;
982 	snd_timer_interrupt(timer, (long)jiff - (long)priv->last_jiffies);
983 }
984 
985 static int snd_timer_s_start(struct snd_timer * timer)
986 {
987 	struct snd_timer_system_private *priv;
988 	unsigned long njiff;
989 
990 	priv = (struct snd_timer_system_private *) timer->private_data;
991 	njiff = (priv->last_jiffies = jiffies);
992 	if (priv->correction > timer->sticks - 1) {
993 		priv->correction -= timer->sticks - 1;
994 		njiff++;
995 	} else {
996 		njiff += timer->sticks - priv->correction;
997 		priv->correction -= timer->sticks;
998 	}
999 	priv->last_expires = priv->tlist.expires = njiff;
1000 	add_timer(&priv->tlist);
1001 	return 0;
1002 }
1003 
1004 static int snd_timer_s_stop(struct snd_timer * timer)
1005 {
1006 	struct snd_timer_system_private *priv;
1007 	unsigned long jiff;
1008 
1009 	priv = (struct snd_timer_system_private *) timer->private_data;
1010 	del_timer(&priv->tlist);
1011 	jiff = jiffies;
1012 	if (time_before(jiff, priv->last_expires))
1013 		timer->sticks = priv->last_expires - jiff;
1014 	else
1015 		timer->sticks = 1;
1016 	return 0;
1017 }
1018 
1019 static struct snd_timer_hardware snd_timer_system =
1020 {
1021 	.flags =	SNDRV_TIMER_HW_FIRST | SNDRV_TIMER_HW_TASKLET,
1022 	.resolution =	1000000000L / HZ,
1023 	.ticks =	10000000L,
1024 	.start =	snd_timer_s_start,
1025 	.stop =		snd_timer_s_stop
1026 };
1027 
1028 static void snd_timer_free_system(struct snd_timer *timer)
1029 {
1030 	kfree(timer->private_data);
1031 }
1032 
1033 static int snd_timer_register_system(void)
1034 {
1035 	struct snd_timer *timer;
1036 	struct snd_timer_system_private *priv;
1037 	int err;
1038 
1039 	err = snd_timer_global_new("system", SNDRV_TIMER_GLOBAL_SYSTEM, &timer);
1040 	if (err < 0)
1041 		return err;
1042 	strcpy(timer->name, "system timer");
1043 	timer->hw = snd_timer_system;
1044 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1045 	if (priv == NULL) {
1046 		snd_timer_free(timer);
1047 		return -ENOMEM;
1048 	}
1049 	init_timer(&priv->tlist);
1050 	priv->tlist.function = snd_timer_s_function;
1051 	priv->tlist.data = (unsigned long) timer;
1052 	timer->private_data = priv;
1053 	timer->private_free = snd_timer_free_system;
1054 	return snd_timer_global_register(timer);
1055 }
1056 
1057 #ifdef CONFIG_PROC_FS
1058 /*
1059  *  Info interface
1060  */
1061 
1062 static void snd_timer_proc_read(struct snd_info_entry *entry,
1063 				struct snd_info_buffer *buffer)
1064 {
1065 	struct snd_timer *timer;
1066 	struct snd_timer_instance *ti;
1067 	struct list_head *p, *q;
1068 
1069 	mutex_lock(&register_mutex);
1070 	list_for_each(p, &snd_timer_list) {
1071 		timer = list_entry(p, struct snd_timer, device_list);
1072 		switch (timer->tmr_class) {
1073 		case SNDRV_TIMER_CLASS_GLOBAL:
1074 			snd_iprintf(buffer, "G%i: ", timer->tmr_device);
1075 			break;
1076 		case SNDRV_TIMER_CLASS_CARD:
1077 			snd_iprintf(buffer, "C%i-%i: ",
1078 				    timer->card->number, timer->tmr_device);
1079 			break;
1080 		case SNDRV_TIMER_CLASS_PCM:
1081 			snd_iprintf(buffer, "P%i-%i-%i: ", timer->card->number,
1082 				    timer->tmr_device, timer->tmr_subdevice);
1083 			break;
1084 		default:
1085 			snd_iprintf(buffer, "?%i-%i-%i-%i: ", timer->tmr_class,
1086 				    timer->card ? timer->card->number : -1,
1087 				    timer->tmr_device, timer->tmr_subdevice);
1088 		}
1089 		snd_iprintf(buffer, "%s :", timer->name);
1090 		if (timer->hw.resolution)
1091 			snd_iprintf(buffer, " %lu.%03luus (%lu ticks)",
1092 				    timer->hw.resolution / 1000,
1093 				    timer->hw.resolution % 1000,
1094 				    timer->hw.ticks);
1095 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
1096 			snd_iprintf(buffer, " SLAVE");
1097 		snd_iprintf(buffer, "\n");
1098 		list_for_each(q, &timer->open_list_head) {
1099 			ti = list_entry(q, struct snd_timer_instance, open_list);
1100 			snd_iprintf(buffer, "  Client %s : %s\n",
1101 				    ti->owner ? ti->owner : "unknown",
1102 				    ti->flags & (SNDRV_TIMER_IFLG_START |
1103 						 SNDRV_TIMER_IFLG_RUNNING)
1104 				    ? "running" : "stopped");
1105 		}
1106 	}
1107 	mutex_unlock(&register_mutex);
1108 }
1109 
1110 static struct snd_info_entry *snd_timer_proc_entry;
1111 
1112 static void __init snd_timer_proc_init(void)
1113 {
1114 	struct snd_info_entry *entry;
1115 
1116 	entry = snd_info_create_module_entry(THIS_MODULE, "timers", NULL);
1117 	if (entry != NULL) {
1118 		entry->c.text.read = snd_timer_proc_read;
1119 		if (snd_info_register(entry) < 0) {
1120 			snd_info_free_entry(entry);
1121 			entry = NULL;
1122 		}
1123 	}
1124 	snd_timer_proc_entry = entry;
1125 }
1126 
1127 static void __exit snd_timer_proc_done(void)
1128 {
1129 	snd_info_unregister(snd_timer_proc_entry);
1130 }
1131 #else /* !CONFIG_PROC_FS */
1132 #define snd_timer_proc_init()
1133 #define snd_timer_proc_done()
1134 #endif
1135 
1136 /*
1137  *  USER SPACE interface
1138  */
1139 
1140 static void snd_timer_user_interrupt(struct snd_timer_instance *timeri,
1141 				     unsigned long resolution,
1142 				     unsigned long ticks)
1143 {
1144 	struct snd_timer_user *tu = timeri->callback_data;
1145 	struct snd_timer_read *r;
1146 	int prev;
1147 
1148 	spin_lock(&tu->qlock);
1149 	if (tu->qused > 0) {
1150 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1151 		r = &tu->queue[prev];
1152 		if (r->resolution == resolution) {
1153 			r->ticks += ticks;
1154 			goto __wake;
1155 		}
1156 	}
1157 	if (tu->qused >= tu->queue_size) {
1158 		tu->overrun++;
1159 	} else {
1160 		r = &tu->queue[tu->qtail++];
1161 		tu->qtail %= tu->queue_size;
1162 		r->resolution = resolution;
1163 		r->ticks = ticks;
1164 		tu->qused++;
1165 	}
1166       __wake:
1167 	spin_unlock(&tu->qlock);
1168 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1169 	wake_up(&tu->qchange_sleep);
1170 }
1171 
1172 static void snd_timer_user_append_to_tqueue(struct snd_timer_user *tu,
1173 					    struct snd_timer_tread *tread)
1174 {
1175 	if (tu->qused >= tu->queue_size) {
1176 		tu->overrun++;
1177 	} else {
1178 		memcpy(&tu->tqueue[tu->qtail++], tread, sizeof(*tread));
1179 		tu->qtail %= tu->queue_size;
1180 		tu->qused++;
1181 	}
1182 }
1183 
1184 static void snd_timer_user_ccallback(struct snd_timer_instance *timeri,
1185 				     int event,
1186 				     struct timespec *tstamp,
1187 				     unsigned long resolution)
1188 {
1189 	struct snd_timer_user *tu = timeri->callback_data;
1190 	struct snd_timer_tread r1;
1191 
1192 	if (event >= SNDRV_TIMER_EVENT_START &&
1193 	    event <= SNDRV_TIMER_EVENT_PAUSE)
1194 		tu->tstamp = *tstamp;
1195 	if ((tu->filter & (1 << event)) == 0 || !tu->tread)
1196 		return;
1197 	r1.event = event;
1198 	r1.tstamp = *tstamp;
1199 	r1.val = resolution;
1200 	spin_lock(&tu->qlock);
1201 	snd_timer_user_append_to_tqueue(tu, &r1);
1202 	spin_unlock(&tu->qlock);
1203 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1204 	wake_up(&tu->qchange_sleep);
1205 }
1206 
1207 static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
1208 				      unsigned long resolution,
1209 				      unsigned long ticks)
1210 {
1211 	struct snd_timer_user *tu = timeri->callback_data;
1212 	struct snd_timer_tread *r, r1;
1213 	struct timespec tstamp;
1214 	int prev, append = 0;
1215 
1216 	memset(&tstamp, 0, sizeof(tstamp));
1217 	spin_lock(&tu->qlock);
1218 	if ((tu->filter & ((1 << SNDRV_TIMER_EVENT_RESOLUTION) |
1219 			   (1 << SNDRV_TIMER_EVENT_TICK))) == 0) {
1220 		spin_unlock(&tu->qlock);
1221 		return;
1222 	}
1223 	if (tu->last_resolution != resolution || ticks > 0)
1224 		getnstimeofday(&tstamp);
1225 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_RESOLUTION)) &&
1226 	    tu->last_resolution != resolution) {
1227 		r1.event = SNDRV_TIMER_EVENT_RESOLUTION;
1228 		r1.tstamp = tstamp;
1229 		r1.val = resolution;
1230 		snd_timer_user_append_to_tqueue(tu, &r1);
1231 		tu->last_resolution = resolution;
1232 		append++;
1233 	}
1234 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_TICK)) == 0)
1235 		goto __wake;
1236 	if (ticks == 0)
1237 		goto __wake;
1238 	if (tu->qused > 0) {
1239 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1240 		r = &tu->tqueue[prev];
1241 		if (r->event == SNDRV_TIMER_EVENT_TICK) {
1242 			r->tstamp = tstamp;
1243 			r->val += ticks;
1244 			append++;
1245 			goto __wake;
1246 		}
1247 	}
1248 	r1.event = SNDRV_TIMER_EVENT_TICK;
1249 	r1.tstamp = tstamp;
1250 	r1.val = ticks;
1251 	snd_timer_user_append_to_tqueue(tu, &r1);
1252 	append++;
1253       __wake:
1254 	spin_unlock(&tu->qlock);
1255 	if (append == 0)
1256 		return;
1257 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1258 	wake_up(&tu->qchange_sleep);
1259 }
1260 
1261 static int snd_timer_user_open(struct inode *inode, struct file *file)
1262 {
1263 	struct snd_timer_user *tu;
1264 
1265 	tu = kzalloc(sizeof(*tu), GFP_KERNEL);
1266 	if (tu == NULL)
1267 		return -ENOMEM;
1268 	spin_lock_init(&tu->qlock);
1269 	init_waitqueue_head(&tu->qchange_sleep);
1270 	mutex_init(&tu->tread_sem);
1271 	tu->ticks = 1;
1272 	tu->queue_size = 128;
1273 	tu->queue = kmalloc(tu->queue_size * sizeof(struct snd_timer_read),
1274 			    GFP_KERNEL);
1275 	if (tu->queue == NULL) {
1276 		kfree(tu);
1277 		return -ENOMEM;
1278 	}
1279 	file->private_data = tu;
1280 	return 0;
1281 }
1282 
1283 static int snd_timer_user_release(struct inode *inode, struct file *file)
1284 {
1285 	struct snd_timer_user *tu;
1286 
1287 	if (file->private_data) {
1288 		tu = file->private_data;
1289 		file->private_data = NULL;
1290 		fasync_helper(-1, file, 0, &tu->fasync);
1291 		if (tu->timeri)
1292 			snd_timer_close(tu->timeri);
1293 		kfree(tu->queue);
1294 		kfree(tu->tqueue);
1295 		kfree(tu);
1296 	}
1297 	return 0;
1298 }
1299 
1300 static void snd_timer_user_zero_id(struct snd_timer_id *id)
1301 {
1302 	id->dev_class = SNDRV_TIMER_CLASS_NONE;
1303 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1304 	id->card = -1;
1305 	id->device = -1;
1306 	id->subdevice = -1;
1307 }
1308 
1309 static void snd_timer_user_copy_id(struct snd_timer_id *id, struct snd_timer *timer)
1310 {
1311 	id->dev_class = timer->tmr_class;
1312 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1313 	id->card = timer->card ? timer->card->number : -1;
1314 	id->device = timer->tmr_device;
1315 	id->subdevice = timer->tmr_subdevice;
1316 }
1317 
1318 static int snd_timer_user_next_device(struct snd_timer_id __user *_tid)
1319 {
1320 	struct snd_timer_id id;
1321 	struct snd_timer *timer;
1322 	struct list_head *p;
1323 
1324 	if (copy_from_user(&id, _tid, sizeof(id)))
1325 		return -EFAULT;
1326 	mutex_lock(&register_mutex);
1327 	if (id.dev_class < 0) {		/* first item */
1328 		if (list_empty(&snd_timer_list))
1329 			snd_timer_user_zero_id(&id);
1330 		else {
1331 			timer = list_entry(snd_timer_list.next,
1332 					   struct snd_timer, device_list);
1333 			snd_timer_user_copy_id(&id, timer);
1334 		}
1335 	} else {
1336 		switch (id.dev_class) {
1337 		case SNDRV_TIMER_CLASS_GLOBAL:
1338 			id.device = id.device < 0 ? 0 : id.device + 1;
1339 			list_for_each(p, &snd_timer_list) {
1340 				timer = list_entry(p, struct snd_timer, device_list);
1341 				if (timer->tmr_class > SNDRV_TIMER_CLASS_GLOBAL) {
1342 					snd_timer_user_copy_id(&id, timer);
1343 					break;
1344 				}
1345 				if (timer->tmr_device >= id.device) {
1346 					snd_timer_user_copy_id(&id, timer);
1347 					break;
1348 				}
1349 			}
1350 			if (p == &snd_timer_list)
1351 				snd_timer_user_zero_id(&id);
1352 			break;
1353 		case SNDRV_TIMER_CLASS_CARD:
1354 		case SNDRV_TIMER_CLASS_PCM:
1355 			if (id.card < 0) {
1356 				id.card = 0;
1357 			} else {
1358 				if (id.card < 0) {
1359 					id.card = 0;
1360 				} else {
1361 					if (id.device < 0) {
1362 						id.device = 0;
1363 					} else {
1364 						if (id.subdevice < 0) {
1365 							id.subdevice = 0;
1366 						} else {
1367 							id.subdevice++;
1368 						}
1369 					}
1370 				}
1371 			}
1372 			list_for_each(p, &snd_timer_list) {
1373 				timer = list_entry(p, struct snd_timer, device_list);
1374 				if (timer->tmr_class > id.dev_class) {
1375 					snd_timer_user_copy_id(&id, timer);
1376 					break;
1377 				}
1378 				if (timer->tmr_class < id.dev_class)
1379 					continue;
1380 				if (timer->card->number > id.card) {
1381 					snd_timer_user_copy_id(&id, timer);
1382 					break;
1383 				}
1384 				if (timer->card->number < id.card)
1385 					continue;
1386 				if (timer->tmr_device > id.device) {
1387 					snd_timer_user_copy_id(&id, timer);
1388 					break;
1389 				}
1390 				if (timer->tmr_device < id.device)
1391 					continue;
1392 				if (timer->tmr_subdevice > id.subdevice) {
1393 					snd_timer_user_copy_id(&id, timer);
1394 					break;
1395 				}
1396 				if (timer->tmr_subdevice < id.subdevice)
1397 					continue;
1398 				snd_timer_user_copy_id(&id, timer);
1399 				break;
1400 			}
1401 			if (p == &snd_timer_list)
1402 				snd_timer_user_zero_id(&id);
1403 			break;
1404 		default:
1405 			snd_timer_user_zero_id(&id);
1406 		}
1407 	}
1408 	mutex_unlock(&register_mutex);
1409 	if (copy_to_user(_tid, &id, sizeof(*_tid)))
1410 		return -EFAULT;
1411 	return 0;
1412 }
1413 
1414 static int snd_timer_user_ginfo(struct file *file,
1415 				struct snd_timer_ginfo __user *_ginfo)
1416 {
1417 	struct snd_timer_ginfo *ginfo;
1418 	struct snd_timer_id tid;
1419 	struct snd_timer *t;
1420 	struct list_head *p;
1421 	int err = 0;
1422 
1423 	ginfo = kmalloc(sizeof(*ginfo), GFP_KERNEL);
1424 	if (! ginfo)
1425 		return -ENOMEM;
1426 	if (copy_from_user(ginfo, _ginfo, sizeof(*ginfo))) {
1427 		kfree(ginfo);
1428 		return -EFAULT;
1429 	}
1430 	tid = ginfo->tid;
1431 	memset(ginfo, 0, sizeof(*ginfo));
1432 	ginfo->tid = tid;
1433 	mutex_lock(&register_mutex);
1434 	t = snd_timer_find(&tid);
1435 	if (t != NULL) {
1436 		ginfo->card = t->card ? t->card->number : -1;
1437 		if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1438 			ginfo->flags |= SNDRV_TIMER_FLG_SLAVE;
1439 		strlcpy(ginfo->id, t->id, sizeof(ginfo->id));
1440 		strlcpy(ginfo->name, t->name, sizeof(ginfo->name));
1441 		ginfo->resolution = t->hw.resolution;
1442 		if (t->hw.resolution_min > 0) {
1443 			ginfo->resolution_min = t->hw.resolution_min;
1444 			ginfo->resolution_max = t->hw.resolution_max;
1445 		}
1446 		list_for_each(p, &t->open_list_head) {
1447 			ginfo->clients++;
1448 		}
1449 	} else {
1450 		err = -ENODEV;
1451 	}
1452 	mutex_unlock(&register_mutex);
1453 	if (err >= 0 && copy_to_user(_ginfo, ginfo, sizeof(*ginfo)))
1454 		err = -EFAULT;
1455 	kfree(ginfo);
1456 	return err;
1457 }
1458 
1459 static int snd_timer_user_gparams(struct file *file,
1460 				  struct snd_timer_gparams __user *_gparams)
1461 {
1462 	struct snd_timer_gparams gparams;
1463 	struct snd_timer *t;
1464 	int err;
1465 
1466 	if (copy_from_user(&gparams, _gparams, sizeof(gparams)))
1467 		return -EFAULT;
1468 	mutex_lock(&register_mutex);
1469 	t = snd_timer_find(&gparams.tid);
1470 	if (!t) {
1471 		err = -ENODEV;
1472 		goto _error;
1473 	}
1474 	if (!list_empty(&t->open_list_head)) {
1475 		err = -EBUSY;
1476 		goto _error;
1477 	}
1478 	if (!t->hw.set_period) {
1479 		err = -ENOSYS;
1480 		goto _error;
1481 	}
1482 	err = t->hw.set_period(t, gparams.period_num, gparams.period_den);
1483 _error:
1484 	mutex_unlock(&register_mutex);
1485 	return err;
1486 }
1487 
1488 static int snd_timer_user_gstatus(struct file *file,
1489 				  struct snd_timer_gstatus __user *_gstatus)
1490 {
1491 	struct snd_timer_gstatus gstatus;
1492 	struct snd_timer_id tid;
1493 	struct snd_timer *t;
1494 	int err = 0;
1495 
1496 	if (copy_from_user(&gstatus, _gstatus, sizeof(gstatus)))
1497 		return -EFAULT;
1498 	tid = gstatus.tid;
1499 	memset(&gstatus, 0, sizeof(gstatus));
1500 	gstatus.tid = tid;
1501 	mutex_lock(&register_mutex);
1502 	t = snd_timer_find(&tid);
1503 	if (t != NULL) {
1504 		if (t->hw.c_resolution)
1505 			gstatus.resolution = t->hw.c_resolution(t);
1506 		else
1507 			gstatus.resolution = t->hw.resolution;
1508 		if (t->hw.precise_resolution) {
1509 			t->hw.precise_resolution(t, &gstatus.resolution_num,
1510 						 &gstatus.resolution_den);
1511 		} else {
1512 			gstatus.resolution_num = gstatus.resolution;
1513 			gstatus.resolution_den = 1000000000uL;
1514 		}
1515 	} else {
1516 		err = -ENODEV;
1517 	}
1518 	mutex_unlock(&register_mutex);
1519 	if (err >= 0 && copy_to_user(_gstatus, &gstatus, sizeof(gstatus)))
1520 		err = -EFAULT;
1521 	return err;
1522 }
1523 
1524 static int snd_timer_user_tselect(struct file *file,
1525 				  struct snd_timer_select __user *_tselect)
1526 {
1527 	struct snd_timer_user *tu;
1528 	struct snd_timer_select tselect;
1529 	char str[32];
1530 	int err = 0;
1531 
1532 	tu = file->private_data;
1533 	mutex_lock(&tu->tread_sem);
1534 	if (tu->timeri) {
1535 		snd_timer_close(tu->timeri);
1536 		tu->timeri = NULL;
1537 	}
1538 	if (copy_from_user(&tselect, _tselect, sizeof(tselect))) {
1539 		err = -EFAULT;
1540 		goto __err;
1541 	}
1542 	sprintf(str, "application %i", current->pid);
1543 	if (tselect.id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
1544 		tselect.id.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION;
1545 	err = snd_timer_open(&tu->timeri, str, &tselect.id, current->pid);
1546 	if (err < 0)
1547 		goto __err;
1548 
1549 	kfree(tu->queue);
1550 	tu->queue = NULL;
1551 	kfree(tu->tqueue);
1552 	tu->tqueue = NULL;
1553 	if (tu->tread) {
1554 		tu->tqueue = kmalloc(tu->queue_size * sizeof(struct snd_timer_tread),
1555 				     GFP_KERNEL);
1556 		if (tu->tqueue == NULL)
1557 			err = -ENOMEM;
1558 	} else {
1559 		tu->queue = kmalloc(tu->queue_size * sizeof(struct snd_timer_read),
1560 				    GFP_KERNEL);
1561 		if (tu->queue == NULL)
1562 			err = -ENOMEM;
1563 	}
1564 
1565       	if (err < 0) {
1566 		snd_timer_close(tu->timeri);
1567       		tu->timeri = NULL;
1568       	} else {
1569 		tu->timeri->flags |= SNDRV_TIMER_IFLG_FAST;
1570 		tu->timeri->callback = tu->tread
1571 			? snd_timer_user_tinterrupt : snd_timer_user_interrupt;
1572 		tu->timeri->ccallback = snd_timer_user_ccallback;
1573 		tu->timeri->callback_data = (void *)tu;
1574 	}
1575 
1576       __err:
1577       	mutex_unlock(&tu->tread_sem);
1578 	return err;
1579 }
1580 
1581 static int snd_timer_user_info(struct file *file,
1582 			       struct snd_timer_info __user *_info)
1583 {
1584 	struct snd_timer_user *tu;
1585 	struct snd_timer_info *info;
1586 	struct snd_timer *t;
1587 	int err = 0;
1588 
1589 	tu = file->private_data;
1590 	snd_assert(tu->timeri != NULL, return -ENXIO);
1591 	t = tu->timeri->timer;
1592 	snd_assert(t != NULL, return -ENXIO);
1593 
1594 	info = kzalloc(sizeof(*info), GFP_KERNEL);
1595 	if (! info)
1596 		return -ENOMEM;
1597 	info->card = t->card ? t->card->number : -1;
1598 	if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1599 		info->flags |= SNDRV_TIMER_FLG_SLAVE;
1600 	strlcpy(info->id, t->id, sizeof(info->id));
1601 	strlcpy(info->name, t->name, sizeof(info->name));
1602 	info->resolution = t->hw.resolution;
1603 	if (copy_to_user(_info, info, sizeof(*_info)))
1604 		err = -EFAULT;
1605 	kfree(info);
1606 	return err;
1607 }
1608 
1609 static int snd_timer_user_params(struct file *file,
1610 				 struct snd_timer_params __user *_params)
1611 {
1612 	struct snd_timer_user *tu;
1613 	struct snd_timer_params params;
1614 	struct snd_timer *t;
1615 	struct snd_timer_read *tr;
1616 	struct snd_timer_tread *ttr;
1617 	int err;
1618 
1619 	tu = file->private_data;
1620 	snd_assert(tu->timeri != NULL, return -ENXIO);
1621 	t = tu->timeri->timer;
1622 	snd_assert(t != NULL, return -ENXIO);
1623 	if (copy_from_user(&params, _params, sizeof(params)))
1624 		return -EFAULT;
1625 	if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE) && params.ticks < 1) {
1626 		err = -EINVAL;
1627 		goto _end;
1628 	}
1629 	if (params.queue_size > 0 &&
1630 	    (params.queue_size < 32 || params.queue_size > 1024)) {
1631 		err = -EINVAL;
1632 		goto _end;
1633 	}
1634 	if (params.filter & ~((1<<SNDRV_TIMER_EVENT_RESOLUTION)|
1635 			      (1<<SNDRV_TIMER_EVENT_TICK)|
1636 			      (1<<SNDRV_TIMER_EVENT_START)|
1637 			      (1<<SNDRV_TIMER_EVENT_STOP)|
1638 			      (1<<SNDRV_TIMER_EVENT_CONTINUE)|
1639 			      (1<<SNDRV_TIMER_EVENT_PAUSE)|
1640 			      (1<<SNDRV_TIMER_EVENT_SUSPEND)|
1641 			      (1<<SNDRV_TIMER_EVENT_RESUME)|
1642 			      (1<<SNDRV_TIMER_EVENT_MSTART)|
1643 			      (1<<SNDRV_TIMER_EVENT_MSTOP)|
1644 			      (1<<SNDRV_TIMER_EVENT_MCONTINUE)|
1645 			      (1<<SNDRV_TIMER_EVENT_MPAUSE)|
1646 			      (1<<SNDRV_TIMER_EVENT_MSUSPEND)|
1647 			      (1<<SNDRV_TIMER_EVENT_MRESUME))) {
1648 		err = -EINVAL;
1649 		goto _end;
1650 	}
1651 	snd_timer_stop(tu->timeri);
1652 	spin_lock_irq(&t->lock);
1653 	tu->timeri->flags &= ~(SNDRV_TIMER_IFLG_AUTO|
1654 			       SNDRV_TIMER_IFLG_EXCLUSIVE|
1655 			       SNDRV_TIMER_IFLG_EARLY_EVENT);
1656 	if (params.flags & SNDRV_TIMER_PSFLG_AUTO)
1657 		tu->timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1658 	if (params.flags & SNDRV_TIMER_PSFLG_EXCLUSIVE)
1659 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EXCLUSIVE;
1660 	if (params.flags & SNDRV_TIMER_PSFLG_EARLY_EVENT)
1661 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EARLY_EVENT;
1662 	spin_unlock_irq(&t->lock);
1663 	if (params.queue_size > 0 &&
1664 	    (unsigned int)tu->queue_size != params.queue_size) {
1665 		if (tu->tread) {
1666 			ttr = kmalloc(params.queue_size * sizeof(*ttr),
1667 				      GFP_KERNEL);
1668 			if (ttr) {
1669 				kfree(tu->tqueue);
1670 				tu->queue_size = params.queue_size;
1671 				tu->tqueue = ttr;
1672 			}
1673 		} else {
1674 			tr = kmalloc(params.queue_size * sizeof(*tr),
1675 				     GFP_KERNEL);
1676 			if (tr) {
1677 				kfree(tu->queue);
1678 				tu->queue_size = params.queue_size;
1679 				tu->queue = tr;
1680 			}
1681 		}
1682 	}
1683 	tu->qhead = tu->qtail = tu->qused = 0;
1684 	if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
1685 		if (tu->tread) {
1686 			struct snd_timer_tread tread;
1687 			tread.event = SNDRV_TIMER_EVENT_EARLY;
1688 			tread.tstamp.tv_sec = 0;
1689 			tread.tstamp.tv_nsec = 0;
1690 			tread.val = 0;
1691 			snd_timer_user_append_to_tqueue(tu, &tread);
1692 		} else {
1693 			struct snd_timer_read *r = &tu->queue[0];
1694 			r->resolution = 0;
1695 			r->ticks = 0;
1696 			tu->qused++;
1697 			tu->qtail++;
1698 		}
1699 	}
1700 	tu->filter = params.filter;
1701 	tu->ticks = params.ticks;
1702 	err = 0;
1703  _end:
1704 	if (copy_to_user(_params, &params, sizeof(params)))
1705 		return -EFAULT;
1706 	return err;
1707 }
1708 
1709 static int snd_timer_user_status(struct file *file,
1710 				 struct snd_timer_status __user *_status)
1711 {
1712 	struct snd_timer_user *tu;
1713 	struct snd_timer_status status;
1714 
1715 	tu = file->private_data;
1716 	snd_assert(tu->timeri != NULL, return -ENXIO);
1717 	memset(&status, 0, sizeof(status));
1718 	status.tstamp = tu->tstamp;
1719 	status.resolution = snd_timer_resolution(tu->timeri);
1720 	status.lost = tu->timeri->lost;
1721 	status.overrun = tu->overrun;
1722 	spin_lock_irq(&tu->qlock);
1723 	status.queue = tu->qused;
1724 	spin_unlock_irq(&tu->qlock);
1725 	if (copy_to_user(_status, &status, sizeof(status)))
1726 		return -EFAULT;
1727 	return 0;
1728 }
1729 
1730 static int snd_timer_user_start(struct file *file)
1731 {
1732 	int err;
1733 	struct snd_timer_user *tu;
1734 
1735 	tu = file->private_data;
1736 	snd_assert(tu->timeri != NULL, return -ENXIO);
1737 	snd_timer_stop(tu->timeri);
1738 	tu->timeri->lost = 0;
1739 	tu->last_resolution = 0;
1740 	return (err = snd_timer_start(tu->timeri, tu->ticks)) < 0 ? err : 0;
1741 }
1742 
1743 static int snd_timer_user_stop(struct file *file)
1744 {
1745 	int err;
1746 	struct snd_timer_user *tu;
1747 
1748 	tu = file->private_data;
1749 	snd_assert(tu->timeri != NULL, return -ENXIO);
1750 	return (err = snd_timer_stop(tu->timeri)) < 0 ? err : 0;
1751 }
1752 
1753 static int snd_timer_user_continue(struct file *file)
1754 {
1755 	int err;
1756 	struct snd_timer_user *tu;
1757 
1758 	tu = file->private_data;
1759 	snd_assert(tu->timeri != NULL, return -ENXIO);
1760 	tu->timeri->lost = 0;
1761 	return (err = snd_timer_continue(tu->timeri)) < 0 ? err : 0;
1762 }
1763 
1764 static int snd_timer_user_pause(struct file *file)
1765 {
1766 	int err;
1767 	struct snd_timer_user *tu;
1768 
1769 	tu = file->private_data;
1770 	snd_assert(tu->timeri != NULL, return -ENXIO);
1771 	return (err = snd_timer_pause(tu->timeri)) < 0 ? err : 0;
1772 }
1773 
1774 enum {
1775 	SNDRV_TIMER_IOCTL_START_OLD = _IO('T', 0x20),
1776 	SNDRV_TIMER_IOCTL_STOP_OLD = _IO('T', 0x21),
1777 	SNDRV_TIMER_IOCTL_CONTINUE_OLD = _IO('T', 0x22),
1778 	SNDRV_TIMER_IOCTL_PAUSE_OLD = _IO('T', 0x23),
1779 };
1780 
1781 static long snd_timer_user_ioctl(struct file *file, unsigned int cmd,
1782 				 unsigned long arg)
1783 {
1784 	struct snd_timer_user *tu;
1785 	void __user *argp = (void __user *)arg;
1786 	int __user *p = argp;
1787 
1788 	tu = file->private_data;
1789 	switch (cmd) {
1790 	case SNDRV_TIMER_IOCTL_PVERSION:
1791 		return put_user(SNDRV_TIMER_VERSION, p) ? -EFAULT : 0;
1792 	case SNDRV_TIMER_IOCTL_NEXT_DEVICE:
1793 		return snd_timer_user_next_device(argp);
1794 	case SNDRV_TIMER_IOCTL_TREAD:
1795 	{
1796 		int xarg;
1797 
1798 		mutex_lock(&tu->tread_sem);
1799 		if (tu->timeri)	{	/* too late */
1800 			mutex_unlock(&tu->tread_sem);
1801 			return -EBUSY;
1802 		}
1803 		if (get_user(xarg, p)) {
1804 			mutex_unlock(&tu->tread_sem);
1805 			return -EFAULT;
1806 		}
1807 		tu->tread = xarg ? 1 : 0;
1808 		mutex_unlock(&tu->tread_sem);
1809 		return 0;
1810 	}
1811 	case SNDRV_TIMER_IOCTL_GINFO:
1812 		return snd_timer_user_ginfo(file, argp);
1813 	case SNDRV_TIMER_IOCTL_GPARAMS:
1814 		return snd_timer_user_gparams(file, argp);
1815 	case SNDRV_TIMER_IOCTL_GSTATUS:
1816 		return snd_timer_user_gstatus(file, argp);
1817 	case SNDRV_TIMER_IOCTL_SELECT:
1818 		return snd_timer_user_tselect(file, argp);
1819 	case SNDRV_TIMER_IOCTL_INFO:
1820 		return snd_timer_user_info(file, argp);
1821 	case SNDRV_TIMER_IOCTL_PARAMS:
1822 		return snd_timer_user_params(file, argp);
1823 	case SNDRV_TIMER_IOCTL_STATUS:
1824 		return snd_timer_user_status(file, argp);
1825 	case SNDRV_TIMER_IOCTL_START:
1826 	case SNDRV_TIMER_IOCTL_START_OLD:
1827 		return snd_timer_user_start(file);
1828 	case SNDRV_TIMER_IOCTL_STOP:
1829 	case SNDRV_TIMER_IOCTL_STOP_OLD:
1830 		return snd_timer_user_stop(file);
1831 	case SNDRV_TIMER_IOCTL_CONTINUE:
1832 	case SNDRV_TIMER_IOCTL_CONTINUE_OLD:
1833 		return snd_timer_user_continue(file);
1834 	case SNDRV_TIMER_IOCTL_PAUSE:
1835 	case SNDRV_TIMER_IOCTL_PAUSE_OLD:
1836 		return snd_timer_user_pause(file);
1837 	}
1838 	return -ENOTTY;
1839 }
1840 
1841 static int snd_timer_user_fasync(int fd, struct file * file, int on)
1842 {
1843 	struct snd_timer_user *tu;
1844 	int err;
1845 
1846 	tu = file->private_data;
1847 	err = fasync_helper(fd, file, on, &tu->fasync);
1848         if (err < 0)
1849 		return err;
1850 	return 0;
1851 }
1852 
1853 static ssize_t snd_timer_user_read(struct file *file, char __user *buffer,
1854 				   size_t count, loff_t *offset)
1855 {
1856 	struct snd_timer_user *tu;
1857 	long result = 0, unit;
1858 	int err = 0;
1859 
1860 	tu = file->private_data;
1861 	unit = tu->tread ? sizeof(struct snd_timer_tread) : sizeof(struct snd_timer_read);
1862 	spin_lock_irq(&tu->qlock);
1863 	while ((long)count - result >= unit) {
1864 		while (!tu->qused) {
1865 			wait_queue_t wait;
1866 
1867 			if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1868 				err = -EAGAIN;
1869 				break;
1870 			}
1871 
1872 			set_current_state(TASK_INTERRUPTIBLE);
1873 			init_waitqueue_entry(&wait, current);
1874 			add_wait_queue(&tu->qchange_sleep, &wait);
1875 
1876 			spin_unlock_irq(&tu->qlock);
1877 			schedule();
1878 			spin_lock_irq(&tu->qlock);
1879 
1880 			remove_wait_queue(&tu->qchange_sleep, &wait);
1881 
1882 			if (signal_pending(current)) {
1883 				err = -ERESTARTSYS;
1884 				break;
1885 			}
1886 		}
1887 
1888 		spin_unlock_irq(&tu->qlock);
1889 		if (err < 0)
1890 			goto _error;
1891 
1892 		if (tu->tread) {
1893 			if (copy_to_user(buffer, &tu->tqueue[tu->qhead++],
1894 					 sizeof(struct snd_timer_tread))) {
1895 				err = -EFAULT;
1896 				goto _error;
1897 			}
1898 		} else {
1899 			if (copy_to_user(buffer, &tu->queue[tu->qhead++],
1900 					 sizeof(struct snd_timer_read))) {
1901 				err = -EFAULT;
1902 				goto _error;
1903 			}
1904 		}
1905 
1906 		tu->qhead %= tu->queue_size;
1907 
1908 		result += unit;
1909 		buffer += unit;
1910 
1911 		spin_lock_irq(&tu->qlock);
1912 		tu->qused--;
1913 	}
1914 	spin_unlock_irq(&tu->qlock);
1915  _error:
1916 	return result > 0 ? result : err;
1917 }
1918 
1919 static unsigned int snd_timer_user_poll(struct file *file, poll_table * wait)
1920 {
1921         unsigned int mask;
1922         struct snd_timer_user *tu;
1923 
1924         tu = file->private_data;
1925 
1926         poll_wait(file, &tu->qchange_sleep, wait);
1927 
1928 	mask = 0;
1929 	if (tu->qused)
1930 		mask |= POLLIN | POLLRDNORM;
1931 
1932 	return mask;
1933 }
1934 
1935 #ifdef CONFIG_COMPAT
1936 #include "timer_compat.c"
1937 #else
1938 #define snd_timer_user_ioctl_compat	NULL
1939 #endif
1940 
1941 static struct file_operations snd_timer_f_ops =
1942 {
1943 	.owner =	THIS_MODULE,
1944 	.read =		snd_timer_user_read,
1945 	.open =		snd_timer_user_open,
1946 	.release =	snd_timer_user_release,
1947 	.poll =		snd_timer_user_poll,
1948 	.unlocked_ioctl =	snd_timer_user_ioctl,
1949 	.compat_ioctl =	snd_timer_user_ioctl_compat,
1950 	.fasync = 	snd_timer_user_fasync,
1951 };
1952 
1953 /*
1954  *  ENTRY functions
1955  */
1956 
1957 static int __init alsa_timer_init(void)
1958 {
1959 	int err;
1960 
1961 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
1962 	snd_oss_info_register(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1,
1963 			      "system timer");
1964 #endif
1965 
1966 	if ((err = snd_timer_register_system()) < 0)
1967 		snd_printk(KERN_ERR "unable to register system timer (%i)\n",
1968 			   err);
1969 	if ((err = snd_register_device(SNDRV_DEVICE_TYPE_TIMER, NULL, 0,
1970 				       &snd_timer_f_ops, NULL, "timer")) < 0)
1971 		snd_printk(KERN_ERR "unable to register timer device (%i)\n",
1972 			   err);
1973 	snd_timer_proc_init();
1974 	return 0;
1975 }
1976 
1977 static void __exit alsa_timer_exit(void)
1978 {
1979 	struct list_head *p, *n;
1980 
1981 	snd_unregister_device(SNDRV_DEVICE_TYPE_TIMER, NULL, 0);
1982 	/* unregister the system timer */
1983 	list_for_each_safe(p, n, &snd_timer_list) {
1984 		struct snd_timer *timer = list_entry(p, struct snd_timer, device_list);
1985 		snd_timer_unregister(timer);
1986 	}
1987 	snd_timer_proc_done();
1988 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
1989 	snd_oss_info_unregister(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1);
1990 #endif
1991 }
1992 
1993 module_init(alsa_timer_init)
1994 module_exit(alsa_timer_exit)
1995 
1996 EXPORT_SYMBOL(snd_timer_open);
1997 EXPORT_SYMBOL(snd_timer_close);
1998 EXPORT_SYMBOL(snd_timer_resolution);
1999 EXPORT_SYMBOL(snd_timer_start);
2000 EXPORT_SYMBOL(snd_timer_stop);
2001 EXPORT_SYMBOL(snd_timer_continue);
2002 EXPORT_SYMBOL(snd_timer_pause);
2003 EXPORT_SYMBOL(snd_timer_new);
2004 EXPORT_SYMBOL(snd_timer_notify);
2005 EXPORT_SYMBOL(snd_timer_global_new);
2006 EXPORT_SYMBOL(snd_timer_global_free);
2007 EXPORT_SYMBOL(snd_timer_global_register);
2008 EXPORT_SYMBOL(snd_timer_global_unregister);
2009 EXPORT_SYMBOL(snd_timer_interrupt);
2010