xref: /linux/sound/core/timer.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
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 
632 	spin_lock(&timer->lock);
633 	/* now process all callbacks */
634 	while (!list_empty(&timer->sack_list_head)) {
635 		p = timer->sack_list_head.next;		/* get first item */
636 		ti = list_entry(p, struct snd_timer_instance, ack_list);
637 
638 		/* remove from ack_list and make empty */
639 		list_del_init(p);
640 
641 		ticks = ti->pticks;
642 		ti->pticks = 0;
643 		resolution = ti->resolution;
644 
645 		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
646 		spin_unlock(&timer->lock);
647 		if (ti->callback)
648 			ti->callback(ti, resolution, ticks);
649 		spin_lock(&timer->lock);
650 		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
651 	}
652 	spin_unlock(&timer->lock);
653 }
654 
655 /*
656  * timer interrupt
657  *
658  * ticks_left is usually equal to timer->sticks.
659  *
660  */
661 void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
662 {
663 	struct snd_timer_instance *ti, *ts;
664 	unsigned long resolution, ticks;
665 	struct list_head *p, *q, *n, *ack_list_head;
666 	unsigned long flags;
667 	int use_tasklet = 0;
668 
669 	if (timer == NULL)
670 		return;
671 
672 	spin_lock_irqsave(&timer->lock, flags);
673 
674 	/* remember the current resolution */
675 	if (timer->hw.c_resolution)
676 		resolution = timer->hw.c_resolution(timer);
677 	else
678 		resolution = timer->hw.resolution;
679 
680 	/* loop for all active instances
681 	 * Here we cannot use list_for_each because the active_list of a
682 	 * processed instance is relinked to done_list_head before the callback
683 	 * is called.
684 	 */
685 	list_for_each_safe(p, n, &timer->active_list_head) {
686 		ti = list_entry(p, struct snd_timer_instance, active_list);
687 		if (!(ti->flags & SNDRV_TIMER_IFLG_RUNNING))
688 			continue;
689 		ti->pticks += ticks_left;
690 		ti->resolution = resolution;
691 		if (ti->cticks < ticks_left)
692 			ti->cticks = 0;
693 		else
694 			ti->cticks -= ticks_left;
695 		if (ti->cticks) /* not expired */
696 			continue;
697 		if (ti->flags & SNDRV_TIMER_IFLG_AUTO) {
698 			ti->cticks = ti->ticks;
699 		} else {
700 			ti->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
701 			if (--timer->running)
702 				list_del(p);
703 		}
704 		if ((timer->hw.flags & SNDRV_TIMER_HW_TASKLET) ||
705 		    (ti->flags & SNDRV_TIMER_IFLG_FAST))
706 			ack_list_head = &timer->ack_list_head;
707 		else
708 			ack_list_head = &timer->sack_list_head;
709 		if (list_empty(&ti->ack_list))
710 			list_add_tail(&ti->ack_list, ack_list_head);
711 		list_for_each(q, &ti->slave_active_head) {
712 			ts = list_entry(q, struct snd_timer_instance, active_list);
713 			ts->pticks = ti->pticks;
714 			ts->resolution = resolution;
715 			if (list_empty(&ts->ack_list))
716 				list_add_tail(&ts->ack_list, ack_list_head);
717 		}
718 	}
719 	if (timer->flags & SNDRV_TIMER_FLG_RESCHED)
720 		snd_timer_reschedule(timer, ticks_left);
721 	if (timer->running) {
722 		if (timer->hw.flags & SNDRV_TIMER_HW_STOP) {
723 			timer->hw.stop(timer);
724 			timer->flags |= SNDRV_TIMER_FLG_CHANGE;
725 		}
726 		if (!(timer->hw.flags & SNDRV_TIMER_HW_AUTO) ||
727 		    (timer->flags & SNDRV_TIMER_FLG_CHANGE)) {
728 			/* restart timer */
729 			timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
730 			timer->hw.start(timer);
731 		}
732 	} else {
733 		timer->hw.stop(timer);
734 	}
735 
736 	/* now process all fast callbacks */
737 	while (!list_empty(&timer->ack_list_head)) {
738 		p = timer->ack_list_head.next;		/* get first item */
739 		ti = list_entry(p, struct snd_timer_instance, ack_list);
740 
741 		/* remove from ack_list and make empty */
742 		list_del_init(p);
743 
744 		ticks = ti->pticks;
745 		ti->pticks = 0;
746 
747 		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
748 		spin_unlock(&timer->lock);
749 		if (ti->callback)
750 			ti->callback(ti, resolution, ticks);
751 		spin_lock(&timer->lock);
752 		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
753 	}
754 
755 	/* do we have any slow callbacks? */
756 	use_tasklet = !list_empty(&timer->sack_list_head);
757 	spin_unlock_irqrestore(&timer->lock, flags);
758 
759 	if (use_tasklet)
760 		tasklet_hi_schedule(&timer->task_queue);
761 }
762 
763 /*
764 
765  */
766 
767 int snd_timer_new(struct snd_card *card, char *id, struct snd_timer_id *tid,
768 		  struct snd_timer **rtimer)
769 {
770 	struct snd_timer *timer;
771 	int err;
772 	static struct snd_device_ops ops = {
773 		.dev_free = snd_timer_dev_free,
774 		.dev_register = snd_timer_dev_register,
775 		.dev_unregister = snd_timer_dev_unregister
776 	};
777 
778 	snd_assert(tid != NULL, return -EINVAL);
779 	snd_assert(rtimer != NULL, return -EINVAL);
780 	*rtimer = NULL;
781 	timer = kzalloc(sizeof(*timer), GFP_KERNEL);
782 	if (timer == NULL) {
783 		snd_printk(KERN_ERR "timer: cannot allocate\n");
784 		return -ENOMEM;
785 	}
786 	timer->tmr_class = tid->dev_class;
787 	timer->card = card;
788 	timer->tmr_device = tid->device;
789 	timer->tmr_subdevice = tid->subdevice;
790 	if (id)
791 		strlcpy(timer->id, id, sizeof(timer->id));
792 	INIT_LIST_HEAD(&timer->device_list);
793 	INIT_LIST_HEAD(&timer->open_list_head);
794 	INIT_LIST_HEAD(&timer->active_list_head);
795 	INIT_LIST_HEAD(&timer->ack_list_head);
796 	INIT_LIST_HEAD(&timer->sack_list_head);
797 	spin_lock_init(&timer->lock);
798 	tasklet_init(&timer->task_queue, snd_timer_tasklet,
799 		     (unsigned long)timer);
800 	if (card != NULL) {
801 		timer->module = card->module;
802 		err = snd_device_new(card, SNDRV_DEV_TIMER, timer, &ops);
803 		if (err < 0) {
804 			snd_timer_free(timer);
805 			return err;
806 		}
807 	}
808 	*rtimer = timer;
809 	return 0;
810 }
811 
812 static int snd_timer_free(struct snd_timer *timer)
813 {
814 	snd_assert(timer != NULL, return -ENXIO);
815 	if (timer->private_free)
816 		timer->private_free(timer);
817 	kfree(timer);
818 	return 0;
819 }
820 
821 static int snd_timer_dev_free(struct snd_device *device)
822 {
823 	struct snd_timer *timer = device->device_data;
824 	return snd_timer_free(timer);
825 }
826 
827 static int snd_timer_dev_register(struct snd_device *dev)
828 {
829 	struct snd_timer *timer = dev->device_data;
830 	struct snd_timer *timer1;
831 	struct list_head *p;
832 
833 	snd_assert(timer != NULL && timer->hw.start != NULL &&
834 		   timer->hw.stop != NULL, return -ENXIO);
835 	if (!(timer->hw.flags & SNDRV_TIMER_HW_SLAVE) &&
836 	    !timer->hw.resolution && timer->hw.c_resolution == NULL)
837 	    	return -EINVAL;
838 
839 	mutex_lock(&register_mutex);
840 	list_for_each(p, &snd_timer_list) {
841 		timer1 = list_entry(p, struct snd_timer, device_list);
842 		if (timer1->tmr_class > timer->tmr_class)
843 			break;
844 		if (timer1->tmr_class < timer->tmr_class)
845 			continue;
846 		if (timer1->card && timer->card) {
847 			if (timer1->card->number > timer->card->number)
848 				break;
849 			if (timer1->card->number < timer->card->number)
850 				continue;
851 		}
852 		if (timer1->tmr_device > timer->tmr_device)
853 			break;
854 		if (timer1->tmr_device < timer->tmr_device)
855 			continue;
856 		if (timer1->tmr_subdevice > timer->tmr_subdevice)
857 			break;
858 		if (timer1->tmr_subdevice < timer->tmr_subdevice)
859 			continue;
860 		/* conflicts.. */
861 		mutex_unlock(&register_mutex);
862 		return -EBUSY;
863 	}
864 	list_add_tail(&timer->device_list, p);
865 	mutex_unlock(&register_mutex);
866 	return 0;
867 }
868 
869 static int snd_timer_unregister(struct snd_timer *timer)
870 {
871 	struct list_head *p, *n;
872 	struct snd_timer_instance *ti;
873 
874 	snd_assert(timer != NULL, return -ENXIO);
875 	mutex_lock(&register_mutex);
876 	if (! list_empty(&timer->open_list_head)) {
877 		snd_printk(KERN_WARNING "timer 0x%lx is busy?\n", (long)timer);
878 		list_for_each_safe(p, n, &timer->open_list_head) {
879 			list_del_init(p);
880 			ti = list_entry(p, struct snd_timer_instance, open_list);
881 			ti->timer = NULL;
882 		}
883 	}
884 	list_del(&timer->device_list);
885 	mutex_unlock(&register_mutex);
886 	return snd_timer_free(timer);
887 }
888 
889 static int snd_timer_dev_unregister(struct snd_device *device)
890 {
891 	struct snd_timer *timer = device->device_data;
892 	return snd_timer_unregister(timer);
893 }
894 
895 void snd_timer_notify(struct snd_timer *timer, int event, struct timespec *tstamp)
896 {
897 	unsigned long flags;
898 	unsigned long resolution = 0;
899 	struct snd_timer_instance *ti, *ts;
900 	struct list_head *p, *n;
901 
902 	if (! (timer->hw.flags & SNDRV_TIMER_HW_SLAVE))
903 		return;
904 	snd_assert(event >= SNDRV_TIMER_EVENT_MSTART &&
905 		   event <= SNDRV_TIMER_EVENT_MRESUME, return);
906 	spin_lock_irqsave(&timer->lock, flags);
907 	if (event == SNDRV_TIMER_EVENT_MSTART ||
908 	    event == SNDRV_TIMER_EVENT_MCONTINUE ||
909 	    event == SNDRV_TIMER_EVENT_MRESUME) {
910 		if (timer->hw.c_resolution)
911 			resolution = timer->hw.c_resolution(timer);
912 		else
913 			resolution = timer->hw.resolution;
914 	}
915 	list_for_each(p, &timer->active_list_head) {
916 		ti = list_entry(p, struct snd_timer_instance, active_list);
917 		if (ti->ccallback)
918 			ti->ccallback(ti, event, tstamp, resolution);
919 		list_for_each(n, &ti->slave_active_head) {
920 			ts = list_entry(n, struct snd_timer_instance, active_list);
921 			if (ts->ccallback)
922 				ts->ccallback(ts, event, tstamp, resolution);
923 		}
924 	}
925 	spin_unlock_irqrestore(&timer->lock, flags);
926 }
927 
928 /*
929  * exported functions for global timers
930  */
931 int snd_timer_global_new(char *id, int device, struct snd_timer **rtimer)
932 {
933 	struct snd_timer_id tid;
934 
935 	tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
936 	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
937 	tid.card = -1;
938 	tid.device = device;
939 	tid.subdevice = 0;
940 	return snd_timer_new(NULL, id, &tid, rtimer);
941 }
942 
943 int snd_timer_global_free(struct snd_timer *timer)
944 {
945 	return snd_timer_free(timer);
946 }
947 
948 int snd_timer_global_register(struct snd_timer *timer)
949 {
950 	struct snd_device dev;
951 
952 	memset(&dev, 0, sizeof(dev));
953 	dev.device_data = timer;
954 	return snd_timer_dev_register(&dev);
955 }
956 
957 int snd_timer_global_unregister(struct snd_timer *timer)
958 {
959 	return snd_timer_unregister(timer);
960 }
961 
962 /*
963  *  System timer
964  */
965 
966 struct snd_timer_system_private {
967 	struct timer_list tlist;
968 	struct timer * timer;
969 	unsigned long last_expires;
970 	unsigned long last_jiffies;
971 	unsigned long correction;
972 };
973 
974 static void snd_timer_s_function(unsigned long data)
975 {
976 	struct snd_timer *timer = (struct snd_timer *)data;
977 	struct snd_timer_system_private *priv = timer->private_data;
978 	unsigned long jiff = jiffies;
979 	if (time_after(jiff, priv->last_expires))
980 		priv->correction = (long)jiff - (long)priv->last_expires;
981 	snd_timer_interrupt(timer, (long)jiff - (long)priv->last_jiffies);
982 }
983 
984 static int snd_timer_s_start(struct snd_timer * timer)
985 {
986 	struct snd_timer_system_private *priv;
987 	unsigned long njiff;
988 
989 	priv = (struct snd_timer_system_private *) timer->private_data;
990 	njiff = (priv->last_jiffies = jiffies);
991 	if (priv->correction > timer->sticks - 1) {
992 		priv->correction -= timer->sticks - 1;
993 		njiff++;
994 	} else {
995 		njiff += timer->sticks - priv->correction;
996 		priv->correction -= timer->sticks;
997 	}
998 	priv->last_expires = priv->tlist.expires = njiff;
999 	add_timer(&priv->tlist);
1000 	return 0;
1001 }
1002 
1003 static int snd_timer_s_stop(struct snd_timer * timer)
1004 {
1005 	struct snd_timer_system_private *priv;
1006 	unsigned long jiff;
1007 
1008 	priv = (struct snd_timer_system_private *) timer->private_data;
1009 	del_timer(&priv->tlist);
1010 	jiff = jiffies;
1011 	if (time_before(jiff, priv->last_expires))
1012 		timer->sticks = priv->last_expires - jiff;
1013 	else
1014 		timer->sticks = 1;
1015 	return 0;
1016 }
1017 
1018 static struct snd_timer_hardware snd_timer_system =
1019 {
1020 	.flags =	SNDRV_TIMER_HW_FIRST | SNDRV_TIMER_HW_TASKLET,
1021 	.resolution =	1000000000L / HZ,
1022 	.ticks =	10000000L,
1023 	.start =	snd_timer_s_start,
1024 	.stop =		snd_timer_s_stop
1025 };
1026 
1027 static void snd_timer_free_system(struct snd_timer *timer)
1028 {
1029 	kfree(timer->private_data);
1030 }
1031 
1032 static int snd_timer_register_system(void)
1033 {
1034 	struct snd_timer *timer;
1035 	struct snd_timer_system_private *priv;
1036 	int err;
1037 
1038 	err = snd_timer_global_new("system", SNDRV_TIMER_GLOBAL_SYSTEM, &timer);
1039 	if (err < 0)
1040 		return err;
1041 	strcpy(timer->name, "system timer");
1042 	timer->hw = snd_timer_system;
1043 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1044 	if (priv == NULL) {
1045 		snd_timer_free(timer);
1046 		return -ENOMEM;
1047 	}
1048 	init_timer(&priv->tlist);
1049 	priv->tlist.function = snd_timer_s_function;
1050 	priv->tlist.data = (unsigned long) timer;
1051 	timer->private_data = priv;
1052 	timer->private_free = snd_timer_free_system;
1053 	return snd_timer_global_register(timer);
1054 }
1055 
1056 #ifdef CONFIG_PROC_FS
1057 /*
1058  *  Info interface
1059  */
1060 
1061 static void snd_timer_proc_read(struct snd_info_entry *entry,
1062 				struct snd_info_buffer *buffer)
1063 {
1064 	struct snd_timer *timer;
1065 	struct snd_timer_instance *ti;
1066 	struct list_head *p, *q;
1067 
1068 	mutex_lock(&register_mutex);
1069 	list_for_each(p, &snd_timer_list) {
1070 		timer = list_entry(p, struct snd_timer, device_list);
1071 		switch (timer->tmr_class) {
1072 		case SNDRV_TIMER_CLASS_GLOBAL:
1073 			snd_iprintf(buffer, "G%i: ", timer->tmr_device);
1074 			break;
1075 		case SNDRV_TIMER_CLASS_CARD:
1076 			snd_iprintf(buffer, "C%i-%i: ",
1077 				    timer->card->number, timer->tmr_device);
1078 			break;
1079 		case SNDRV_TIMER_CLASS_PCM:
1080 			snd_iprintf(buffer, "P%i-%i-%i: ", timer->card->number,
1081 				    timer->tmr_device, timer->tmr_subdevice);
1082 			break;
1083 		default:
1084 			snd_iprintf(buffer, "?%i-%i-%i-%i: ", timer->tmr_class,
1085 				    timer->card ? timer->card->number : -1,
1086 				    timer->tmr_device, timer->tmr_subdevice);
1087 		}
1088 		snd_iprintf(buffer, "%s :", timer->name);
1089 		if (timer->hw.resolution)
1090 			snd_iprintf(buffer, " %lu.%03luus (%lu ticks)",
1091 				    timer->hw.resolution / 1000,
1092 				    timer->hw.resolution % 1000,
1093 				    timer->hw.ticks);
1094 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
1095 			snd_iprintf(buffer, " SLAVE");
1096 		snd_iprintf(buffer, "\n");
1097 		list_for_each(q, &timer->open_list_head) {
1098 			ti = list_entry(q, struct snd_timer_instance, open_list);
1099 			snd_iprintf(buffer, "  Client %s : %s\n",
1100 				    ti->owner ? ti->owner : "unknown",
1101 				    ti->flags & (SNDRV_TIMER_IFLG_START |
1102 						 SNDRV_TIMER_IFLG_RUNNING)
1103 				    ? "running" : "stopped");
1104 		}
1105 	}
1106 	mutex_unlock(&register_mutex);
1107 }
1108 
1109 static struct snd_info_entry *snd_timer_proc_entry;
1110 
1111 static void __init snd_timer_proc_init(void)
1112 {
1113 	struct snd_info_entry *entry;
1114 
1115 	entry = snd_info_create_module_entry(THIS_MODULE, "timers", NULL);
1116 	if (entry != NULL) {
1117 		entry->c.text.read = snd_timer_proc_read;
1118 		if (snd_info_register(entry) < 0) {
1119 			snd_info_free_entry(entry);
1120 			entry = NULL;
1121 		}
1122 	}
1123 	snd_timer_proc_entry = entry;
1124 }
1125 
1126 static void __exit snd_timer_proc_done(void)
1127 {
1128 	snd_info_unregister(snd_timer_proc_entry);
1129 }
1130 #else /* !CONFIG_PROC_FS */
1131 #define snd_timer_proc_init()
1132 #define snd_timer_proc_done()
1133 #endif
1134 
1135 /*
1136  *  USER SPACE interface
1137  */
1138 
1139 static void snd_timer_user_interrupt(struct snd_timer_instance *timeri,
1140 				     unsigned long resolution,
1141 				     unsigned long ticks)
1142 {
1143 	struct snd_timer_user *tu = timeri->callback_data;
1144 	struct snd_timer_read *r;
1145 	int prev;
1146 
1147 	spin_lock(&tu->qlock);
1148 	if (tu->qused > 0) {
1149 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1150 		r = &tu->queue[prev];
1151 		if (r->resolution == resolution) {
1152 			r->ticks += ticks;
1153 			goto __wake;
1154 		}
1155 	}
1156 	if (tu->qused >= tu->queue_size) {
1157 		tu->overrun++;
1158 	} else {
1159 		r = &tu->queue[tu->qtail++];
1160 		tu->qtail %= tu->queue_size;
1161 		r->resolution = resolution;
1162 		r->ticks = ticks;
1163 		tu->qused++;
1164 	}
1165       __wake:
1166 	spin_unlock(&tu->qlock);
1167 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1168 	wake_up(&tu->qchange_sleep);
1169 }
1170 
1171 static void snd_timer_user_append_to_tqueue(struct snd_timer_user *tu,
1172 					    struct snd_timer_tread *tread)
1173 {
1174 	if (tu->qused >= tu->queue_size) {
1175 		tu->overrun++;
1176 	} else {
1177 		memcpy(&tu->tqueue[tu->qtail++], tread, sizeof(*tread));
1178 		tu->qtail %= tu->queue_size;
1179 		tu->qused++;
1180 	}
1181 }
1182 
1183 static void snd_timer_user_ccallback(struct snd_timer_instance *timeri,
1184 				     int event,
1185 				     struct timespec *tstamp,
1186 				     unsigned long resolution)
1187 {
1188 	struct snd_timer_user *tu = timeri->callback_data;
1189 	struct snd_timer_tread r1;
1190 
1191 	if (event >= SNDRV_TIMER_EVENT_START &&
1192 	    event <= SNDRV_TIMER_EVENT_PAUSE)
1193 		tu->tstamp = *tstamp;
1194 	if ((tu->filter & (1 << event)) == 0 || !tu->tread)
1195 		return;
1196 	r1.event = event;
1197 	r1.tstamp = *tstamp;
1198 	r1.val = resolution;
1199 	spin_lock(&tu->qlock);
1200 	snd_timer_user_append_to_tqueue(tu, &r1);
1201 	spin_unlock(&tu->qlock);
1202 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1203 	wake_up(&tu->qchange_sleep);
1204 }
1205 
1206 static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
1207 				      unsigned long resolution,
1208 				      unsigned long ticks)
1209 {
1210 	struct snd_timer_user *tu = timeri->callback_data;
1211 	struct snd_timer_tread *r, r1;
1212 	struct timespec tstamp;
1213 	int prev, append = 0;
1214 
1215 	memset(&tstamp, 0, sizeof(tstamp));
1216 	spin_lock(&tu->qlock);
1217 	if ((tu->filter & ((1 << SNDRV_TIMER_EVENT_RESOLUTION) |
1218 			   (1 << SNDRV_TIMER_EVENT_TICK))) == 0) {
1219 		spin_unlock(&tu->qlock);
1220 		return;
1221 	}
1222 	if (tu->last_resolution != resolution || ticks > 0)
1223 		getnstimeofday(&tstamp);
1224 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_RESOLUTION)) &&
1225 	    tu->last_resolution != resolution) {
1226 		r1.event = SNDRV_TIMER_EVENT_RESOLUTION;
1227 		r1.tstamp = tstamp;
1228 		r1.val = resolution;
1229 		snd_timer_user_append_to_tqueue(tu, &r1);
1230 		tu->last_resolution = resolution;
1231 		append++;
1232 	}
1233 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_TICK)) == 0)
1234 		goto __wake;
1235 	if (ticks == 0)
1236 		goto __wake;
1237 	if (tu->qused > 0) {
1238 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1239 		r = &tu->tqueue[prev];
1240 		if (r->event == SNDRV_TIMER_EVENT_TICK) {
1241 			r->tstamp = tstamp;
1242 			r->val += ticks;
1243 			append++;
1244 			goto __wake;
1245 		}
1246 	}
1247 	r1.event = SNDRV_TIMER_EVENT_TICK;
1248 	r1.tstamp = tstamp;
1249 	r1.val = ticks;
1250 	snd_timer_user_append_to_tqueue(tu, &r1);
1251 	append++;
1252       __wake:
1253 	spin_unlock(&tu->qlock);
1254 	if (append == 0)
1255 		return;
1256 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1257 	wake_up(&tu->qchange_sleep);
1258 }
1259 
1260 static int snd_timer_user_open(struct inode *inode, struct file *file)
1261 {
1262 	struct snd_timer_user *tu;
1263 
1264 	tu = kzalloc(sizeof(*tu), GFP_KERNEL);
1265 	if (tu == NULL)
1266 		return -ENOMEM;
1267 	spin_lock_init(&tu->qlock);
1268 	init_waitqueue_head(&tu->qchange_sleep);
1269 	mutex_init(&tu->tread_sem);
1270 	tu->ticks = 1;
1271 	tu->queue_size = 128;
1272 	tu->queue = kmalloc(tu->queue_size * sizeof(struct snd_timer_read),
1273 			    GFP_KERNEL);
1274 	if (tu->queue == NULL) {
1275 		kfree(tu);
1276 		return -ENOMEM;
1277 	}
1278 	file->private_data = tu;
1279 	return 0;
1280 }
1281 
1282 static int snd_timer_user_release(struct inode *inode, struct file *file)
1283 {
1284 	struct snd_timer_user *tu;
1285 
1286 	if (file->private_data) {
1287 		tu = file->private_data;
1288 		file->private_data = NULL;
1289 		fasync_helper(-1, file, 0, &tu->fasync);
1290 		if (tu->timeri)
1291 			snd_timer_close(tu->timeri);
1292 		kfree(tu->queue);
1293 		kfree(tu->tqueue);
1294 		kfree(tu);
1295 	}
1296 	return 0;
1297 }
1298 
1299 static void snd_timer_user_zero_id(struct snd_timer_id *id)
1300 {
1301 	id->dev_class = SNDRV_TIMER_CLASS_NONE;
1302 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1303 	id->card = -1;
1304 	id->device = -1;
1305 	id->subdevice = -1;
1306 }
1307 
1308 static void snd_timer_user_copy_id(struct snd_timer_id *id, struct snd_timer *timer)
1309 {
1310 	id->dev_class = timer->tmr_class;
1311 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1312 	id->card = timer->card ? timer->card->number : -1;
1313 	id->device = timer->tmr_device;
1314 	id->subdevice = timer->tmr_subdevice;
1315 }
1316 
1317 static int snd_timer_user_next_device(struct snd_timer_id __user *_tid)
1318 {
1319 	struct snd_timer_id id;
1320 	struct snd_timer *timer;
1321 	struct list_head *p;
1322 
1323 	if (copy_from_user(&id, _tid, sizeof(id)))
1324 		return -EFAULT;
1325 	mutex_lock(&register_mutex);
1326 	if (id.dev_class < 0) {		/* first item */
1327 		if (list_empty(&snd_timer_list))
1328 			snd_timer_user_zero_id(&id);
1329 		else {
1330 			timer = list_entry(snd_timer_list.next,
1331 					   struct snd_timer, device_list);
1332 			snd_timer_user_copy_id(&id, timer);
1333 		}
1334 	} else {
1335 		switch (id.dev_class) {
1336 		case SNDRV_TIMER_CLASS_GLOBAL:
1337 			id.device = id.device < 0 ? 0 : id.device + 1;
1338 			list_for_each(p, &snd_timer_list) {
1339 				timer = list_entry(p, struct snd_timer, device_list);
1340 				if (timer->tmr_class > SNDRV_TIMER_CLASS_GLOBAL) {
1341 					snd_timer_user_copy_id(&id, timer);
1342 					break;
1343 				}
1344 				if (timer->tmr_device >= id.device) {
1345 					snd_timer_user_copy_id(&id, timer);
1346 					break;
1347 				}
1348 			}
1349 			if (p == &snd_timer_list)
1350 				snd_timer_user_zero_id(&id);
1351 			break;
1352 		case SNDRV_TIMER_CLASS_CARD:
1353 		case SNDRV_TIMER_CLASS_PCM:
1354 			if (id.card < 0) {
1355 				id.card = 0;
1356 			} else {
1357 				if (id.card < 0) {
1358 					id.card = 0;
1359 				} else {
1360 					if (id.device < 0) {
1361 						id.device = 0;
1362 					} else {
1363 						if (id.subdevice < 0) {
1364 							id.subdevice = 0;
1365 						} else {
1366 							id.subdevice++;
1367 						}
1368 					}
1369 				}
1370 			}
1371 			list_for_each(p, &snd_timer_list) {
1372 				timer = list_entry(p, struct snd_timer, device_list);
1373 				if (timer->tmr_class > id.dev_class) {
1374 					snd_timer_user_copy_id(&id, timer);
1375 					break;
1376 				}
1377 				if (timer->tmr_class < id.dev_class)
1378 					continue;
1379 				if (timer->card->number > id.card) {
1380 					snd_timer_user_copy_id(&id, timer);
1381 					break;
1382 				}
1383 				if (timer->card->number < id.card)
1384 					continue;
1385 				if (timer->tmr_device > id.device) {
1386 					snd_timer_user_copy_id(&id, timer);
1387 					break;
1388 				}
1389 				if (timer->tmr_device < id.device)
1390 					continue;
1391 				if (timer->tmr_subdevice > id.subdevice) {
1392 					snd_timer_user_copy_id(&id, timer);
1393 					break;
1394 				}
1395 				if (timer->tmr_subdevice < id.subdevice)
1396 					continue;
1397 				snd_timer_user_copy_id(&id, timer);
1398 				break;
1399 			}
1400 			if (p == &snd_timer_list)
1401 				snd_timer_user_zero_id(&id);
1402 			break;
1403 		default:
1404 			snd_timer_user_zero_id(&id);
1405 		}
1406 	}
1407 	mutex_unlock(&register_mutex);
1408 	if (copy_to_user(_tid, &id, sizeof(*_tid)))
1409 		return -EFAULT;
1410 	return 0;
1411 }
1412 
1413 static int snd_timer_user_ginfo(struct file *file,
1414 				struct snd_timer_ginfo __user *_ginfo)
1415 {
1416 	struct snd_timer_ginfo *ginfo;
1417 	struct snd_timer_id tid;
1418 	struct snd_timer *t;
1419 	struct list_head *p;
1420 	int err = 0;
1421 
1422 	ginfo = kmalloc(sizeof(*ginfo), GFP_KERNEL);
1423 	if (! ginfo)
1424 		return -ENOMEM;
1425 	if (copy_from_user(ginfo, _ginfo, sizeof(*ginfo))) {
1426 		kfree(ginfo);
1427 		return -EFAULT;
1428 	}
1429 	tid = ginfo->tid;
1430 	memset(ginfo, 0, sizeof(*ginfo));
1431 	ginfo->tid = tid;
1432 	mutex_lock(&register_mutex);
1433 	t = snd_timer_find(&tid);
1434 	if (t != NULL) {
1435 		ginfo->card = t->card ? t->card->number : -1;
1436 		if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1437 			ginfo->flags |= SNDRV_TIMER_FLG_SLAVE;
1438 		strlcpy(ginfo->id, t->id, sizeof(ginfo->id));
1439 		strlcpy(ginfo->name, t->name, sizeof(ginfo->name));
1440 		ginfo->resolution = t->hw.resolution;
1441 		if (t->hw.resolution_min > 0) {
1442 			ginfo->resolution_min = t->hw.resolution_min;
1443 			ginfo->resolution_max = t->hw.resolution_max;
1444 		}
1445 		list_for_each(p, &t->open_list_head) {
1446 			ginfo->clients++;
1447 		}
1448 	} else {
1449 		err = -ENODEV;
1450 	}
1451 	mutex_unlock(&register_mutex);
1452 	if (err >= 0 && copy_to_user(_ginfo, ginfo, sizeof(*ginfo)))
1453 		err = -EFAULT;
1454 	kfree(ginfo);
1455 	return err;
1456 }
1457 
1458 static int snd_timer_user_gparams(struct file *file,
1459 				  struct snd_timer_gparams __user *_gparams)
1460 {
1461 	struct snd_timer_gparams gparams;
1462 	struct snd_timer *t;
1463 	int err;
1464 
1465 	if (copy_from_user(&gparams, _gparams, sizeof(gparams)))
1466 		return -EFAULT;
1467 	mutex_lock(&register_mutex);
1468 	t = snd_timer_find(&gparams.tid);
1469 	if (!t) {
1470 		err = -ENODEV;
1471 		goto _error;
1472 	}
1473 	if (!list_empty(&t->open_list_head)) {
1474 		err = -EBUSY;
1475 		goto _error;
1476 	}
1477 	if (!t->hw.set_period) {
1478 		err = -ENOSYS;
1479 		goto _error;
1480 	}
1481 	err = t->hw.set_period(t, gparams.period_num, gparams.period_den);
1482 _error:
1483 	mutex_unlock(&register_mutex);
1484 	return err;
1485 }
1486 
1487 static int snd_timer_user_gstatus(struct file *file,
1488 				  struct snd_timer_gstatus __user *_gstatus)
1489 {
1490 	struct snd_timer_gstatus gstatus;
1491 	struct snd_timer_id tid;
1492 	struct snd_timer *t;
1493 	int err = 0;
1494 
1495 	if (copy_from_user(&gstatus, _gstatus, sizeof(gstatus)))
1496 		return -EFAULT;
1497 	tid = gstatus.tid;
1498 	memset(&gstatus, 0, sizeof(gstatus));
1499 	gstatus.tid = tid;
1500 	mutex_lock(&register_mutex);
1501 	t = snd_timer_find(&tid);
1502 	if (t != NULL) {
1503 		if (t->hw.c_resolution)
1504 			gstatus.resolution = t->hw.c_resolution(t);
1505 		else
1506 			gstatus.resolution = t->hw.resolution;
1507 		if (t->hw.precise_resolution) {
1508 			t->hw.precise_resolution(t, &gstatus.resolution_num,
1509 						 &gstatus.resolution_den);
1510 		} else {
1511 			gstatus.resolution_num = gstatus.resolution;
1512 			gstatus.resolution_den = 1000000000uL;
1513 		}
1514 	} else {
1515 		err = -ENODEV;
1516 	}
1517 	mutex_unlock(&register_mutex);
1518 	if (err >= 0 && copy_to_user(_gstatus, &gstatus, sizeof(gstatus)))
1519 		err = -EFAULT;
1520 	return err;
1521 }
1522 
1523 static int snd_timer_user_tselect(struct file *file,
1524 				  struct snd_timer_select __user *_tselect)
1525 {
1526 	struct snd_timer_user *tu;
1527 	struct snd_timer_select tselect;
1528 	char str[32];
1529 	int err = 0;
1530 
1531 	tu = file->private_data;
1532 	mutex_lock(&tu->tread_sem);
1533 	if (tu->timeri) {
1534 		snd_timer_close(tu->timeri);
1535 		tu->timeri = NULL;
1536 	}
1537 	if (copy_from_user(&tselect, _tselect, sizeof(tselect))) {
1538 		err = -EFAULT;
1539 		goto __err;
1540 	}
1541 	sprintf(str, "application %i", current->pid);
1542 	if (tselect.id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
1543 		tselect.id.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION;
1544 	err = snd_timer_open(&tu->timeri, str, &tselect.id, current->pid);
1545 	if (err < 0)
1546 		goto __err;
1547 
1548 	kfree(tu->queue);
1549 	tu->queue = NULL;
1550 	kfree(tu->tqueue);
1551 	tu->tqueue = NULL;
1552 	if (tu->tread) {
1553 		tu->tqueue = kmalloc(tu->queue_size * sizeof(struct snd_timer_tread),
1554 				     GFP_KERNEL);
1555 		if (tu->tqueue == NULL)
1556 			err = -ENOMEM;
1557 	} else {
1558 		tu->queue = kmalloc(tu->queue_size * sizeof(struct snd_timer_read),
1559 				    GFP_KERNEL);
1560 		if (tu->queue == NULL)
1561 			err = -ENOMEM;
1562 	}
1563 
1564       	if (err < 0) {
1565 		snd_timer_close(tu->timeri);
1566       		tu->timeri = NULL;
1567       	} else {
1568 		tu->timeri->flags |= SNDRV_TIMER_IFLG_FAST;
1569 		tu->timeri->callback = tu->tread
1570 			? snd_timer_user_tinterrupt : snd_timer_user_interrupt;
1571 		tu->timeri->ccallback = snd_timer_user_ccallback;
1572 		tu->timeri->callback_data = (void *)tu;
1573 	}
1574 
1575       __err:
1576       	mutex_unlock(&tu->tread_sem);
1577 	return err;
1578 }
1579 
1580 static int snd_timer_user_info(struct file *file,
1581 			       struct snd_timer_info __user *_info)
1582 {
1583 	struct snd_timer_user *tu;
1584 	struct snd_timer_info *info;
1585 	struct snd_timer *t;
1586 	int err = 0;
1587 
1588 	tu = file->private_data;
1589 	snd_assert(tu->timeri != NULL, return -ENXIO);
1590 	t = tu->timeri->timer;
1591 	snd_assert(t != NULL, return -ENXIO);
1592 
1593 	info = kzalloc(sizeof(*info), GFP_KERNEL);
1594 	if (! info)
1595 		return -ENOMEM;
1596 	info->card = t->card ? t->card->number : -1;
1597 	if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1598 		info->flags |= SNDRV_TIMER_FLG_SLAVE;
1599 	strlcpy(info->id, t->id, sizeof(info->id));
1600 	strlcpy(info->name, t->name, sizeof(info->name));
1601 	info->resolution = t->hw.resolution;
1602 	if (copy_to_user(_info, info, sizeof(*_info)))
1603 		err = -EFAULT;
1604 	kfree(info);
1605 	return err;
1606 }
1607 
1608 static int snd_timer_user_params(struct file *file,
1609 				 struct snd_timer_params __user *_params)
1610 {
1611 	struct snd_timer_user *tu;
1612 	struct snd_timer_params params;
1613 	struct snd_timer *t;
1614 	struct snd_timer_read *tr;
1615 	struct snd_timer_tread *ttr;
1616 	int err;
1617 
1618 	tu = file->private_data;
1619 	snd_assert(tu->timeri != NULL, return -ENXIO);
1620 	t = tu->timeri->timer;
1621 	snd_assert(t != NULL, return -ENXIO);
1622 	if (copy_from_user(&params, _params, sizeof(params)))
1623 		return -EFAULT;
1624 	if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE) && params.ticks < 1) {
1625 		err = -EINVAL;
1626 		goto _end;
1627 	}
1628 	if (params.queue_size > 0 &&
1629 	    (params.queue_size < 32 || params.queue_size > 1024)) {
1630 		err = -EINVAL;
1631 		goto _end;
1632 	}
1633 	if (params.filter & ~((1<<SNDRV_TIMER_EVENT_RESOLUTION)|
1634 			      (1<<SNDRV_TIMER_EVENT_TICK)|
1635 			      (1<<SNDRV_TIMER_EVENT_START)|
1636 			      (1<<SNDRV_TIMER_EVENT_STOP)|
1637 			      (1<<SNDRV_TIMER_EVENT_CONTINUE)|
1638 			      (1<<SNDRV_TIMER_EVENT_PAUSE)|
1639 			      (1<<SNDRV_TIMER_EVENT_SUSPEND)|
1640 			      (1<<SNDRV_TIMER_EVENT_RESUME)|
1641 			      (1<<SNDRV_TIMER_EVENT_MSTART)|
1642 			      (1<<SNDRV_TIMER_EVENT_MSTOP)|
1643 			      (1<<SNDRV_TIMER_EVENT_MCONTINUE)|
1644 			      (1<<SNDRV_TIMER_EVENT_MPAUSE)|
1645 			      (1<<SNDRV_TIMER_EVENT_MSUSPEND)|
1646 			      (1<<SNDRV_TIMER_EVENT_MRESUME))) {
1647 		err = -EINVAL;
1648 		goto _end;
1649 	}
1650 	snd_timer_stop(tu->timeri);
1651 	spin_lock_irq(&t->lock);
1652 	tu->timeri->flags &= ~(SNDRV_TIMER_IFLG_AUTO|
1653 			       SNDRV_TIMER_IFLG_EXCLUSIVE|
1654 			       SNDRV_TIMER_IFLG_EARLY_EVENT);
1655 	if (params.flags & SNDRV_TIMER_PSFLG_AUTO)
1656 		tu->timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1657 	if (params.flags & SNDRV_TIMER_PSFLG_EXCLUSIVE)
1658 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EXCLUSIVE;
1659 	if (params.flags & SNDRV_TIMER_PSFLG_EARLY_EVENT)
1660 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EARLY_EVENT;
1661 	spin_unlock_irq(&t->lock);
1662 	if (params.queue_size > 0 &&
1663 	    (unsigned int)tu->queue_size != params.queue_size) {
1664 		if (tu->tread) {
1665 			ttr = kmalloc(params.queue_size * sizeof(*ttr),
1666 				      GFP_KERNEL);
1667 			if (ttr) {
1668 				kfree(tu->tqueue);
1669 				tu->queue_size = params.queue_size;
1670 				tu->tqueue = ttr;
1671 			}
1672 		} else {
1673 			tr = kmalloc(params.queue_size * sizeof(*tr),
1674 				     GFP_KERNEL);
1675 			if (tr) {
1676 				kfree(tu->queue);
1677 				tu->queue_size = params.queue_size;
1678 				tu->queue = tr;
1679 			}
1680 		}
1681 	}
1682 	tu->qhead = tu->qtail = tu->qused = 0;
1683 	if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
1684 		if (tu->tread) {
1685 			struct snd_timer_tread tread;
1686 			tread.event = SNDRV_TIMER_EVENT_EARLY;
1687 			tread.tstamp.tv_sec = 0;
1688 			tread.tstamp.tv_nsec = 0;
1689 			tread.val = 0;
1690 			snd_timer_user_append_to_tqueue(tu, &tread);
1691 		} else {
1692 			struct snd_timer_read *r = &tu->queue[0];
1693 			r->resolution = 0;
1694 			r->ticks = 0;
1695 			tu->qused++;
1696 			tu->qtail++;
1697 		}
1698 	}
1699 	tu->filter = params.filter;
1700 	tu->ticks = params.ticks;
1701 	err = 0;
1702  _end:
1703 	if (copy_to_user(_params, &params, sizeof(params)))
1704 		return -EFAULT;
1705 	return err;
1706 }
1707 
1708 static int snd_timer_user_status(struct file *file,
1709 				 struct snd_timer_status __user *_status)
1710 {
1711 	struct snd_timer_user *tu;
1712 	struct snd_timer_status status;
1713 
1714 	tu = file->private_data;
1715 	snd_assert(tu->timeri != NULL, return -ENXIO);
1716 	memset(&status, 0, sizeof(status));
1717 	status.tstamp = tu->tstamp;
1718 	status.resolution = snd_timer_resolution(tu->timeri);
1719 	status.lost = tu->timeri->lost;
1720 	status.overrun = tu->overrun;
1721 	spin_lock_irq(&tu->qlock);
1722 	status.queue = tu->qused;
1723 	spin_unlock_irq(&tu->qlock);
1724 	if (copy_to_user(_status, &status, sizeof(status)))
1725 		return -EFAULT;
1726 	return 0;
1727 }
1728 
1729 static int snd_timer_user_start(struct file *file)
1730 {
1731 	int err;
1732 	struct snd_timer_user *tu;
1733 
1734 	tu = file->private_data;
1735 	snd_assert(tu->timeri != NULL, return -ENXIO);
1736 	snd_timer_stop(tu->timeri);
1737 	tu->timeri->lost = 0;
1738 	tu->last_resolution = 0;
1739 	return (err = snd_timer_start(tu->timeri, tu->ticks)) < 0 ? err : 0;
1740 }
1741 
1742 static int snd_timer_user_stop(struct file *file)
1743 {
1744 	int err;
1745 	struct snd_timer_user *tu;
1746 
1747 	tu = file->private_data;
1748 	snd_assert(tu->timeri != NULL, return -ENXIO);
1749 	return (err = snd_timer_stop(tu->timeri)) < 0 ? err : 0;
1750 }
1751 
1752 static int snd_timer_user_continue(struct file *file)
1753 {
1754 	int err;
1755 	struct snd_timer_user *tu;
1756 
1757 	tu = file->private_data;
1758 	snd_assert(tu->timeri != NULL, return -ENXIO);
1759 	tu->timeri->lost = 0;
1760 	return (err = snd_timer_continue(tu->timeri)) < 0 ? err : 0;
1761 }
1762 
1763 static int snd_timer_user_pause(struct file *file)
1764 {
1765 	int err;
1766 	struct snd_timer_user *tu;
1767 
1768 	tu = file->private_data;
1769 	snd_assert(tu->timeri != NULL, return -ENXIO);
1770 	return (err = snd_timer_pause(tu->timeri)) < 0 ? err : 0;
1771 }
1772 
1773 enum {
1774 	SNDRV_TIMER_IOCTL_START_OLD = _IO('T', 0x20),
1775 	SNDRV_TIMER_IOCTL_STOP_OLD = _IO('T', 0x21),
1776 	SNDRV_TIMER_IOCTL_CONTINUE_OLD = _IO('T', 0x22),
1777 	SNDRV_TIMER_IOCTL_PAUSE_OLD = _IO('T', 0x23),
1778 };
1779 
1780 static long snd_timer_user_ioctl(struct file *file, unsigned int cmd,
1781 				 unsigned long arg)
1782 {
1783 	struct snd_timer_user *tu;
1784 	void __user *argp = (void __user *)arg;
1785 	int __user *p = argp;
1786 
1787 	tu = file->private_data;
1788 	switch (cmd) {
1789 	case SNDRV_TIMER_IOCTL_PVERSION:
1790 		return put_user(SNDRV_TIMER_VERSION, p) ? -EFAULT : 0;
1791 	case SNDRV_TIMER_IOCTL_NEXT_DEVICE:
1792 		return snd_timer_user_next_device(argp);
1793 	case SNDRV_TIMER_IOCTL_TREAD:
1794 	{
1795 		int xarg;
1796 
1797 		mutex_lock(&tu->tread_sem);
1798 		if (tu->timeri)	{	/* too late */
1799 			mutex_unlock(&tu->tread_sem);
1800 			return -EBUSY;
1801 		}
1802 		if (get_user(xarg, p)) {
1803 			mutex_unlock(&tu->tread_sem);
1804 			return -EFAULT;
1805 		}
1806 		tu->tread = xarg ? 1 : 0;
1807 		mutex_unlock(&tu->tread_sem);
1808 		return 0;
1809 	}
1810 	case SNDRV_TIMER_IOCTL_GINFO:
1811 		return snd_timer_user_ginfo(file, argp);
1812 	case SNDRV_TIMER_IOCTL_GPARAMS:
1813 		return snd_timer_user_gparams(file, argp);
1814 	case SNDRV_TIMER_IOCTL_GSTATUS:
1815 		return snd_timer_user_gstatus(file, argp);
1816 	case SNDRV_TIMER_IOCTL_SELECT:
1817 		return snd_timer_user_tselect(file, argp);
1818 	case SNDRV_TIMER_IOCTL_INFO:
1819 		return snd_timer_user_info(file, argp);
1820 	case SNDRV_TIMER_IOCTL_PARAMS:
1821 		return snd_timer_user_params(file, argp);
1822 	case SNDRV_TIMER_IOCTL_STATUS:
1823 		return snd_timer_user_status(file, argp);
1824 	case SNDRV_TIMER_IOCTL_START:
1825 	case SNDRV_TIMER_IOCTL_START_OLD:
1826 		return snd_timer_user_start(file);
1827 	case SNDRV_TIMER_IOCTL_STOP:
1828 	case SNDRV_TIMER_IOCTL_STOP_OLD:
1829 		return snd_timer_user_stop(file);
1830 	case SNDRV_TIMER_IOCTL_CONTINUE:
1831 	case SNDRV_TIMER_IOCTL_CONTINUE_OLD:
1832 		return snd_timer_user_continue(file);
1833 	case SNDRV_TIMER_IOCTL_PAUSE:
1834 	case SNDRV_TIMER_IOCTL_PAUSE_OLD:
1835 		return snd_timer_user_pause(file);
1836 	}
1837 	return -ENOTTY;
1838 }
1839 
1840 static int snd_timer_user_fasync(int fd, struct file * file, int on)
1841 {
1842 	struct snd_timer_user *tu;
1843 	int err;
1844 
1845 	tu = file->private_data;
1846 	err = fasync_helper(fd, file, on, &tu->fasync);
1847         if (err < 0)
1848 		return err;
1849 	return 0;
1850 }
1851 
1852 static ssize_t snd_timer_user_read(struct file *file, char __user *buffer,
1853 				   size_t count, loff_t *offset)
1854 {
1855 	struct snd_timer_user *tu;
1856 	long result = 0, unit;
1857 	int err = 0;
1858 
1859 	tu = file->private_data;
1860 	unit = tu->tread ? sizeof(struct snd_timer_tread) : sizeof(struct snd_timer_read);
1861 	spin_lock_irq(&tu->qlock);
1862 	while ((long)count - result >= unit) {
1863 		while (!tu->qused) {
1864 			wait_queue_t wait;
1865 
1866 			if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1867 				err = -EAGAIN;
1868 				break;
1869 			}
1870 
1871 			set_current_state(TASK_INTERRUPTIBLE);
1872 			init_waitqueue_entry(&wait, current);
1873 			add_wait_queue(&tu->qchange_sleep, &wait);
1874 
1875 			spin_unlock_irq(&tu->qlock);
1876 			schedule();
1877 			spin_lock_irq(&tu->qlock);
1878 
1879 			remove_wait_queue(&tu->qchange_sleep, &wait);
1880 
1881 			if (signal_pending(current)) {
1882 				err = -ERESTARTSYS;
1883 				break;
1884 			}
1885 		}
1886 
1887 		spin_unlock_irq(&tu->qlock);
1888 		if (err < 0)
1889 			goto _error;
1890 
1891 		if (tu->tread) {
1892 			if (copy_to_user(buffer, &tu->tqueue[tu->qhead++],
1893 					 sizeof(struct snd_timer_tread))) {
1894 				err = -EFAULT;
1895 				goto _error;
1896 			}
1897 		} else {
1898 			if (copy_to_user(buffer, &tu->queue[tu->qhead++],
1899 					 sizeof(struct snd_timer_read))) {
1900 				err = -EFAULT;
1901 				goto _error;
1902 			}
1903 		}
1904 
1905 		tu->qhead %= tu->queue_size;
1906 
1907 		result += unit;
1908 		buffer += unit;
1909 
1910 		spin_lock_irq(&tu->qlock);
1911 		tu->qused--;
1912 	}
1913 	spin_unlock_irq(&tu->qlock);
1914  _error:
1915 	return result > 0 ? result : err;
1916 }
1917 
1918 static unsigned int snd_timer_user_poll(struct file *file, poll_table * wait)
1919 {
1920         unsigned int mask;
1921         struct snd_timer_user *tu;
1922 
1923         tu = file->private_data;
1924 
1925         poll_wait(file, &tu->qchange_sleep, wait);
1926 
1927 	mask = 0;
1928 	if (tu->qused)
1929 		mask |= POLLIN | POLLRDNORM;
1930 
1931 	return mask;
1932 }
1933 
1934 #ifdef CONFIG_COMPAT
1935 #include "timer_compat.c"
1936 #else
1937 #define snd_timer_user_ioctl_compat	NULL
1938 #endif
1939 
1940 static struct file_operations snd_timer_f_ops =
1941 {
1942 	.owner =	THIS_MODULE,
1943 	.read =		snd_timer_user_read,
1944 	.open =		snd_timer_user_open,
1945 	.release =	snd_timer_user_release,
1946 	.poll =		snd_timer_user_poll,
1947 	.unlocked_ioctl =	snd_timer_user_ioctl,
1948 	.compat_ioctl =	snd_timer_user_ioctl_compat,
1949 	.fasync = 	snd_timer_user_fasync,
1950 };
1951 
1952 /*
1953  *  ENTRY functions
1954  */
1955 
1956 static int __init alsa_timer_init(void)
1957 {
1958 	int err;
1959 
1960 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
1961 	snd_oss_info_register(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1,
1962 			      "system timer");
1963 #endif
1964 
1965 	if ((err = snd_timer_register_system()) < 0)
1966 		snd_printk(KERN_ERR "unable to register system timer (%i)\n",
1967 			   err);
1968 	if ((err = snd_register_device(SNDRV_DEVICE_TYPE_TIMER, NULL, 0,
1969 				       &snd_timer_f_ops, NULL, "timer")) < 0)
1970 		snd_printk(KERN_ERR "unable to register timer device (%i)\n",
1971 			   err);
1972 	snd_timer_proc_init();
1973 	return 0;
1974 }
1975 
1976 static void __exit alsa_timer_exit(void)
1977 {
1978 	struct list_head *p, *n;
1979 
1980 	snd_unregister_device(SNDRV_DEVICE_TYPE_TIMER, NULL, 0);
1981 	/* unregister the system timer */
1982 	list_for_each_safe(p, n, &snd_timer_list) {
1983 		struct snd_timer *timer = list_entry(p, struct snd_timer, device_list);
1984 		snd_timer_unregister(timer);
1985 	}
1986 	snd_timer_proc_done();
1987 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
1988 	snd_oss_info_unregister(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1);
1989 #endif
1990 }
1991 
1992 module_init(alsa_timer_init)
1993 module_exit(alsa_timer_exit)
1994 
1995 EXPORT_SYMBOL(snd_timer_open);
1996 EXPORT_SYMBOL(snd_timer_close);
1997 EXPORT_SYMBOL(snd_timer_resolution);
1998 EXPORT_SYMBOL(snd_timer_start);
1999 EXPORT_SYMBOL(snd_timer_stop);
2000 EXPORT_SYMBOL(snd_timer_continue);
2001 EXPORT_SYMBOL(snd_timer_pause);
2002 EXPORT_SYMBOL(snd_timer_new);
2003 EXPORT_SYMBOL(snd_timer_notify);
2004 EXPORT_SYMBOL(snd_timer_global_new);
2005 EXPORT_SYMBOL(snd_timer_global_free);
2006 EXPORT_SYMBOL(snd_timer_global_register);
2007 EXPORT_SYMBOL(snd_timer_global_unregister);
2008 EXPORT_SYMBOL(snd_timer_interrupt);
2009