xref: /openbmc/linux/sound/core/timer.c (revision 455f9726)
1 /*
2  *  Timers abstract layer
3  *  Copyright (c) by Jaroslav Kysela <perex@perex.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 <linux/delay.h>
23 #include <linux/init.h>
24 #include <linux/slab.h>
25 #include <linux/time.h>
26 #include <linux/mutex.h>
27 #include <linux/device.h>
28 #include <linux/module.h>
29 #include <linux/string.h>
30 #include <sound/core.h>
31 #include <sound/timer.h>
32 #include <sound/control.h>
33 #include <sound/info.h>
34 #include <sound/minors.h>
35 #include <sound/initval.h>
36 #include <linux/kmod.h>
37 
38 #if IS_ENABLED(CONFIG_SND_HRTIMER)
39 #define DEFAULT_TIMER_LIMIT 4
40 #elif IS_ENABLED(CONFIG_SND_RTCTIMER)
41 #define DEFAULT_TIMER_LIMIT 2
42 #else
43 #define DEFAULT_TIMER_LIMIT 1
44 #endif
45 
46 static int timer_limit = DEFAULT_TIMER_LIMIT;
47 static int timer_tstamp_monotonic = 1;
48 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.de>");
49 MODULE_DESCRIPTION("ALSA timer interface");
50 MODULE_LICENSE("GPL");
51 module_param(timer_limit, int, 0444);
52 MODULE_PARM_DESC(timer_limit, "Maximum global timers in system.");
53 module_param(timer_tstamp_monotonic, int, 0444);
54 MODULE_PARM_DESC(timer_tstamp_monotonic, "Use posix monotonic clock source for timestamps (default).");
55 
56 MODULE_ALIAS_CHARDEV(CONFIG_SND_MAJOR, SNDRV_MINOR_TIMER);
57 MODULE_ALIAS("devname:snd/timer");
58 
59 struct snd_timer_user {
60 	struct snd_timer_instance *timeri;
61 	int tread;		/* enhanced read with timestamps and events */
62 	unsigned long ticks;
63 	unsigned long overrun;
64 	int qhead;
65 	int qtail;
66 	int qused;
67 	int queue_size;
68 	struct snd_timer_read *queue;
69 	struct snd_timer_tread *tqueue;
70 	spinlock_t qlock;
71 	unsigned long last_resolution;
72 	unsigned int filter;
73 	struct timespec tstamp;		/* trigger tstamp */
74 	wait_queue_head_t qchange_sleep;
75 	struct fasync_struct *fasync;
76 	struct mutex tread_sem;
77 };
78 
79 /* list of timers */
80 static LIST_HEAD(snd_timer_list);
81 
82 /* list of slave instances */
83 static LIST_HEAD(snd_timer_slave_list);
84 
85 /* lock for slave active lists */
86 static DEFINE_SPINLOCK(slave_active_lock);
87 
88 static DEFINE_MUTEX(register_mutex);
89 
90 static int snd_timer_free(struct snd_timer *timer);
91 static int snd_timer_dev_free(struct snd_device *device);
92 static int snd_timer_dev_register(struct snd_device *device);
93 static int snd_timer_dev_disconnect(struct snd_device *device);
94 
95 static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left);
96 
97 /*
98  * create a timer instance with the given owner string.
99  * when timer is not NULL, increments the module counter
100  */
101 static struct snd_timer_instance *snd_timer_instance_new(char *owner,
102 							 struct snd_timer *timer)
103 {
104 	struct snd_timer_instance *timeri;
105 	timeri = kzalloc(sizeof(*timeri), GFP_KERNEL);
106 	if (timeri == NULL)
107 		return NULL;
108 	timeri->owner = kstrdup(owner, GFP_KERNEL);
109 	if (! timeri->owner) {
110 		kfree(timeri);
111 		return NULL;
112 	}
113 	INIT_LIST_HEAD(&timeri->open_list);
114 	INIT_LIST_HEAD(&timeri->active_list);
115 	INIT_LIST_HEAD(&timeri->ack_list);
116 	INIT_LIST_HEAD(&timeri->slave_list_head);
117 	INIT_LIST_HEAD(&timeri->slave_active_head);
118 
119 	timeri->timer = timer;
120 	if (timer && !try_module_get(timer->module)) {
121 		kfree(timeri->owner);
122 		kfree(timeri);
123 		return NULL;
124 	}
125 
126 	return timeri;
127 }
128 
129 /*
130  * find a timer instance from the given timer id
131  */
132 static struct snd_timer *snd_timer_find(struct snd_timer_id *tid)
133 {
134 	struct snd_timer *timer = NULL;
135 
136 	list_for_each_entry(timer, &snd_timer_list, device_list) {
137 		if (timer->tmr_class != tid->dev_class)
138 			continue;
139 		if ((timer->tmr_class == SNDRV_TIMER_CLASS_CARD ||
140 		     timer->tmr_class == SNDRV_TIMER_CLASS_PCM) &&
141 		    (timer->card == NULL ||
142 		     timer->card->number != tid->card))
143 			continue;
144 		if (timer->tmr_device != tid->device)
145 			continue;
146 		if (timer->tmr_subdevice != tid->subdevice)
147 			continue;
148 		return timer;
149 	}
150 	return NULL;
151 }
152 
153 #ifdef CONFIG_MODULES
154 
155 static void snd_timer_request(struct snd_timer_id *tid)
156 {
157 	switch (tid->dev_class) {
158 	case SNDRV_TIMER_CLASS_GLOBAL:
159 		if (tid->device < timer_limit)
160 			request_module("snd-timer-%i", tid->device);
161 		break;
162 	case SNDRV_TIMER_CLASS_CARD:
163 	case SNDRV_TIMER_CLASS_PCM:
164 		if (tid->card < snd_ecards_limit)
165 			request_module("snd-card-%i", tid->card);
166 		break;
167 	default:
168 		break;
169 	}
170 }
171 
172 #endif
173 
174 /*
175  * look for a master instance matching with the slave id of the given slave.
176  * when found, relink the open_link of the slave.
177  *
178  * call this with register_mutex down.
179  */
180 static void snd_timer_check_slave(struct snd_timer_instance *slave)
181 {
182 	struct snd_timer *timer;
183 	struct snd_timer_instance *master;
184 
185 	/* FIXME: it's really dumb to look up all entries.. */
186 	list_for_each_entry(timer, &snd_timer_list, device_list) {
187 		list_for_each_entry(master, &timer->open_list_head, open_list) {
188 			if (slave->slave_class == master->slave_class &&
189 			    slave->slave_id == master->slave_id) {
190 				list_move_tail(&slave->open_list,
191 					       &master->slave_list_head);
192 				spin_lock_irq(&slave_active_lock);
193 				slave->master = master;
194 				slave->timer = master->timer;
195 				spin_unlock_irq(&slave_active_lock);
196 				return;
197 			}
198 		}
199 	}
200 }
201 
202 /*
203  * look for slave instances matching with the slave id of the given master.
204  * when found, relink the open_link of slaves.
205  *
206  * call this with register_mutex down.
207  */
208 static void snd_timer_check_master(struct snd_timer_instance *master)
209 {
210 	struct snd_timer_instance *slave, *tmp;
211 
212 	/* check all pending slaves */
213 	list_for_each_entry_safe(slave, tmp, &snd_timer_slave_list, open_list) {
214 		if (slave->slave_class == master->slave_class &&
215 		    slave->slave_id == master->slave_id) {
216 			list_move_tail(&slave->open_list, &master->slave_list_head);
217 			spin_lock_irq(&slave_active_lock);
218 			slave->master = master;
219 			slave->timer = master->timer;
220 			if (slave->flags & SNDRV_TIMER_IFLG_RUNNING)
221 				list_add_tail(&slave->active_list,
222 					      &master->slave_active_head);
223 			spin_unlock_irq(&slave_active_lock);
224 		}
225 	}
226 }
227 
228 /*
229  * open a timer instance
230  * when opening a master, the slave id must be here given.
231  */
232 int snd_timer_open(struct snd_timer_instance **ti,
233 		   char *owner, struct snd_timer_id *tid,
234 		   unsigned int slave_id)
235 {
236 	struct snd_timer *timer;
237 	struct snd_timer_instance *timeri = NULL;
238 
239 	if (tid->dev_class == SNDRV_TIMER_CLASS_SLAVE) {
240 		/* open a slave instance */
241 		if (tid->dev_sclass <= SNDRV_TIMER_SCLASS_NONE ||
242 		    tid->dev_sclass > SNDRV_TIMER_SCLASS_OSS_SEQUENCER) {
243 			pr_debug("ALSA: timer: invalid slave class %i\n",
244 				 tid->dev_sclass);
245 			return -EINVAL;
246 		}
247 		mutex_lock(&register_mutex);
248 		timeri = snd_timer_instance_new(owner, NULL);
249 		if (!timeri) {
250 			mutex_unlock(&register_mutex);
251 			return -ENOMEM;
252 		}
253 		timeri->slave_class = tid->dev_sclass;
254 		timeri->slave_id = tid->device;
255 		timeri->flags |= SNDRV_TIMER_IFLG_SLAVE;
256 		list_add_tail(&timeri->open_list, &snd_timer_slave_list);
257 		snd_timer_check_slave(timeri);
258 		mutex_unlock(&register_mutex);
259 		*ti = timeri;
260 		return 0;
261 	}
262 
263 	/* open a master instance */
264 	mutex_lock(&register_mutex);
265 	timer = snd_timer_find(tid);
266 #ifdef CONFIG_MODULES
267 	if (!timer) {
268 		mutex_unlock(&register_mutex);
269 		snd_timer_request(tid);
270 		mutex_lock(&register_mutex);
271 		timer = snd_timer_find(tid);
272 	}
273 #endif
274 	if (!timer) {
275 		mutex_unlock(&register_mutex);
276 		return -ENODEV;
277 	}
278 	if (!list_empty(&timer->open_list_head)) {
279 		timeri = list_entry(timer->open_list_head.next,
280 				    struct snd_timer_instance, open_list);
281 		if (timeri->flags & SNDRV_TIMER_IFLG_EXCLUSIVE) {
282 			mutex_unlock(&register_mutex);
283 			return -EBUSY;
284 		}
285 	}
286 	timeri = snd_timer_instance_new(owner, timer);
287 	if (!timeri) {
288 		mutex_unlock(&register_mutex);
289 		return -ENOMEM;
290 	}
291 	timeri->slave_class = tid->dev_sclass;
292 	timeri->slave_id = slave_id;
293 	if (list_empty(&timer->open_list_head) && timer->hw.open)
294 		timer->hw.open(timer);
295 	list_add_tail(&timeri->open_list, &timer->open_list_head);
296 	snd_timer_check_master(timeri);
297 	mutex_unlock(&register_mutex);
298 	*ti = timeri;
299 	return 0;
300 }
301 
302 static int _snd_timer_stop(struct snd_timer_instance *timeri,
303 			   int keep_flag, int event);
304 
305 /*
306  * close a timer instance
307  */
308 int snd_timer_close(struct snd_timer_instance *timeri)
309 {
310 	struct snd_timer *timer = NULL;
311 	struct snd_timer_instance *slave, *tmp;
312 
313 	if (snd_BUG_ON(!timeri))
314 		return -ENXIO;
315 
316 	/* force to stop the timer */
317 	snd_timer_stop(timeri);
318 
319 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) {
320 		/* wait, until the active callback is finished */
321 		spin_lock_irq(&slave_active_lock);
322 		while (timeri->flags & SNDRV_TIMER_IFLG_CALLBACK) {
323 			spin_unlock_irq(&slave_active_lock);
324 			udelay(10);
325 			spin_lock_irq(&slave_active_lock);
326 		}
327 		spin_unlock_irq(&slave_active_lock);
328 		mutex_lock(&register_mutex);
329 		list_del(&timeri->open_list);
330 		mutex_unlock(&register_mutex);
331 	} else {
332 		timer = timeri->timer;
333 		if (snd_BUG_ON(!timer))
334 			goto out;
335 		/* wait, until the active callback is finished */
336 		spin_lock_irq(&timer->lock);
337 		while (timeri->flags & SNDRV_TIMER_IFLG_CALLBACK) {
338 			spin_unlock_irq(&timer->lock);
339 			udelay(10);
340 			spin_lock_irq(&timer->lock);
341 		}
342 		spin_unlock_irq(&timer->lock);
343 		mutex_lock(&register_mutex);
344 		list_del(&timeri->open_list);
345 		if (timer && list_empty(&timer->open_list_head) &&
346 		    timer->hw.close)
347 			timer->hw.close(timer);
348 		/* remove slave links */
349 		list_for_each_entry_safe(slave, tmp, &timeri->slave_list_head,
350 					 open_list) {
351 			spin_lock_irq(&slave_active_lock);
352 			_snd_timer_stop(slave, 1, SNDRV_TIMER_EVENT_RESOLUTION);
353 			list_move_tail(&slave->open_list, &snd_timer_slave_list);
354 			slave->master = NULL;
355 			slave->timer = NULL;
356 			spin_unlock_irq(&slave_active_lock);
357 		}
358 		mutex_unlock(&register_mutex);
359 	}
360  out:
361 	if (timeri->private_free)
362 		timeri->private_free(timeri);
363 	kfree(timeri->owner);
364 	kfree(timeri);
365 	if (timer)
366 		module_put(timer->module);
367 	return 0;
368 }
369 
370 unsigned long snd_timer_resolution(struct snd_timer_instance *timeri)
371 {
372 	struct snd_timer * timer;
373 
374 	if (timeri == NULL)
375 		return 0;
376 	if ((timer = timeri->timer) != NULL) {
377 		if (timer->hw.c_resolution)
378 			return timer->hw.c_resolution(timer);
379 		return timer->hw.resolution;
380 	}
381 	return 0;
382 }
383 
384 static void snd_timer_notify1(struct snd_timer_instance *ti, int event)
385 {
386 	struct snd_timer *timer;
387 	unsigned long flags;
388 	unsigned long resolution = 0;
389 	struct snd_timer_instance *ts;
390 	struct timespec tstamp;
391 
392 	if (timer_tstamp_monotonic)
393 		ktime_get_ts(&tstamp);
394 	else
395 		getnstimeofday(&tstamp);
396 	if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_START ||
397 		       event > SNDRV_TIMER_EVENT_PAUSE))
398 		return;
399 	if (event == SNDRV_TIMER_EVENT_START ||
400 	    event == SNDRV_TIMER_EVENT_CONTINUE)
401 		resolution = snd_timer_resolution(ti);
402 	if (ti->ccallback)
403 		ti->ccallback(ti, event, &tstamp, resolution);
404 	if (ti->flags & SNDRV_TIMER_IFLG_SLAVE)
405 		return;
406 	timer = ti->timer;
407 	if (timer == NULL)
408 		return;
409 	if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
410 		return;
411 	spin_lock_irqsave(&timer->lock, flags);
412 	list_for_each_entry(ts, &ti->slave_active_head, active_list)
413 		if (ts->ccallback)
414 			ts->ccallback(ti, event + 100, &tstamp, resolution);
415 	spin_unlock_irqrestore(&timer->lock, flags);
416 }
417 
418 static int snd_timer_start1(struct snd_timer *timer, struct snd_timer_instance *timeri,
419 			    unsigned long sticks)
420 {
421 	list_move_tail(&timeri->active_list, &timer->active_list_head);
422 	if (timer->running) {
423 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
424 			goto __start_now;
425 		timer->flags |= SNDRV_TIMER_FLG_RESCHED;
426 		timeri->flags |= SNDRV_TIMER_IFLG_START;
427 		return 1;	/* delayed start */
428 	} else {
429 		timer->sticks = sticks;
430 		timer->hw.start(timer);
431 	      __start_now:
432 		timer->running++;
433 		timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
434 		return 0;
435 	}
436 }
437 
438 static int snd_timer_start_slave(struct snd_timer_instance *timeri)
439 {
440 	unsigned long flags;
441 
442 	spin_lock_irqsave(&slave_active_lock, flags);
443 	timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
444 	if (timeri->master)
445 		list_add_tail(&timeri->active_list,
446 			      &timeri->master->slave_active_head);
447 	spin_unlock_irqrestore(&slave_active_lock, flags);
448 	return 1; /* delayed start */
449 }
450 
451 /*
452  *  start the timer instance
453  */
454 int snd_timer_start(struct snd_timer_instance *timeri, unsigned int ticks)
455 {
456 	struct snd_timer *timer;
457 	int result = -EINVAL;
458 	unsigned long flags;
459 
460 	if (timeri == NULL || ticks < 1)
461 		return -EINVAL;
462 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) {
463 		result = snd_timer_start_slave(timeri);
464 		snd_timer_notify1(timeri, SNDRV_TIMER_EVENT_START);
465 		return result;
466 	}
467 	timer = timeri->timer;
468 	if (timer == NULL)
469 		return -EINVAL;
470 	spin_lock_irqsave(&timer->lock, flags);
471 	timeri->ticks = timeri->cticks = ticks;
472 	timeri->pticks = 0;
473 	result = snd_timer_start1(timer, timeri, ticks);
474 	spin_unlock_irqrestore(&timer->lock, flags);
475 	snd_timer_notify1(timeri, SNDRV_TIMER_EVENT_START);
476 	return result;
477 }
478 
479 static int _snd_timer_stop(struct snd_timer_instance * timeri,
480 			   int keep_flag, int event)
481 {
482 	struct snd_timer *timer;
483 	unsigned long flags;
484 
485 	if (snd_BUG_ON(!timeri))
486 		return -ENXIO;
487 
488 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) {
489 		if (!keep_flag) {
490 			spin_lock_irqsave(&slave_active_lock, flags);
491 			timeri->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
492 			spin_unlock_irqrestore(&slave_active_lock, flags);
493 		}
494 		goto __end;
495 	}
496 	timer = timeri->timer;
497 	if (!timer)
498 		return -EINVAL;
499 	spin_lock_irqsave(&timer->lock, flags);
500 	list_del_init(&timeri->ack_list);
501 	list_del_init(&timeri->active_list);
502 	if ((timeri->flags & SNDRV_TIMER_IFLG_RUNNING) &&
503 	    !(--timer->running)) {
504 		timer->hw.stop(timer);
505 		if (timer->flags & SNDRV_TIMER_FLG_RESCHED) {
506 			timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
507 			snd_timer_reschedule(timer, 0);
508 			if (timer->flags & SNDRV_TIMER_FLG_CHANGE) {
509 				timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
510 				timer->hw.start(timer);
511 			}
512 		}
513 	}
514 	if (!keep_flag)
515 		timeri->flags &=
516 			~(SNDRV_TIMER_IFLG_RUNNING | SNDRV_TIMER_IFLG_START);
517 	spin_unlock_irqrestore(&timer->lock, flags);
518       __end:
519 	if (event != SNDRV_TIMER_EVENT_RESOLUTION)
520 		snd_timer_notify1(timeri, event);
521 	return 0;
522 }
523 
524 /*
525  * stop the timer instance.
526  *
527  * do not call this from the timer callback!
528  */
529 int snd_timer_stop(struct snd_timer_instance *timeri)
530 {
531 	struct snd_timer *timer;
532 	unsigned long flags;
533 	int err;
534 
535 	err = _snd_timer_stop(timeri, 0, SNDRV_TIMER_EVENT_STOP);
536 	if (err < 0)
537 		return err;
538 	timer = timeri->timer;
539 	if (!timer)
540 		return -EINVAL;
541 	spin_lock_irqsave(&timer->lock, flags);
542 	timeri->cticks = timeri->ticks;
543 	timeri->pticks = 0;
544 	spin_unlock_irqrestore(&timer->lock, flags);
545 	return 0;
546 }
547 
548 /*
549  * start again..  the tick is kept.
550  */
551 int snd_timer_continue(struct snd_timer_instance *timeri)
552 {
553 	struct snd_timer *timer;
554 	int result = -EINVAL;
555 	unsigned long flags;
556 
557 	if (timeri == NULL)
558 		return result;
559 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
560 		return snd_timer_start_slave(timeri);
561 	timer = timeri->timer;
562 	if (! timer)
563 		return -EINVAL;
564 	spin_lock_irqsave(&timer->lock, flags);
565 	if (!timeri->cticks)
566 		timeri->cticks = 1;
567 	timeri->pticks = 0;
568 	result = snd_timer_start1(timer, timeri, timer->sticks);
569 	spin_unlock_irqrestore(&timer->lock, flags);
570 	snd_timer_notify1(timeri, SNDRV_TIMER_EVENT_CONTINUE);
571 	return result;
572 }
573 
574 /*
575  * pause.. remember the ticks left
576  */
577 int snd_timer_pause(struct snd_timer_instance * timeri)
578 {
579 	return _snd_timer_stop(timeri, 0, SNDRV_TIMER_EVENT_PAUSE);
580 }
581 
582 /*
583  * reschedule the timer
584  *
585  * start pending instances and check the scheduling ticks.
586  * when the scheduling ticks is changed set CHANGE flag to reprogram the timer.
587  */
588 static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left)
589 {
590 	struct snd_timer_instance *ti;
591 	unsigned long ticks = ~0UL;
592 
593 	list_for_each_entry(ti, &timer->active_list_head, active_list) {
594 		if (ti->flags & SNDRV_TIMER_IFLG_START) {
595 			ti->flags &= ~SNDRV_TIMER_IFLG_START;
596 			ti->flags |= SNDRV_TIMER_IFLG_RUNNING;
597 			timer->running++;
598 		}
599 		if (ti->flags & SNDRV_TIMER_IFLG_RUNNING) {
600 			if (ticks > ti->cticks)
601 				ticks = ti->cticks;
602 		}
603 	}
604 	if (ticks == ~0UL) {
605 		timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
606 		return;
607 	}
608 	if (ticks > timer->hw.ticks)
609 		ticks = timer->hw.ticks;
610 	if (ticks_left != ticks)
611 		timer->flags |= SNDRV_TIMER_FLG_CHANGE;
612 	timer->sticks = ticks;
613 }
614 
615 /*
616  * timer tasklet
617  *
618  */
619 static void snd_timer_tasklet(unsigned long arg)
620 {
621 	struct snd_timer *timer = (struct snd_timer *) arg;
622 	struct snd_timer_instance *ti;
623 	struct list_head *p;
624 	unsigned long resolution, ticks;
625 	unsigned long flags;
626 
627 	spin_lock_irqsave(&timer->lock, flags);
628 	/* now process all callbacks */
629 	while (!list_empty(&timer->sack_list_head)) {
630 		p = timer->sack_list_head.next;		/* get first item */
631 		ti = list_entry(p, struct snd_timer_instance, ack_list);
632 
633 		/* remove from ack_list and make empty */
634 		list_del_init(p);
635 
636 		ticks = ti->pticks;
637 		ti->pticks = 0;
638 		resolution = ti->resolution;
639 
640 		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
641 		spin_unlock(&timer->lock);
642 		if (ti->callback)
643 			ti->callback(ti, resolution, ticks);
644 		spin_lock(&timer->lock);
645 		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
646 	}
647 	spin_unlock_irqrestore(&timer->lock, flags);
648 }
649 
650 /*
651  * timer interrupt
652  *
653  * ticks_left is usually equal to timer->sticks.
654  *
655  */
656 void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
657 {
658 	struct snd_timer_instance *ti, *ts, *tmp;
659 	unsigned long resolution, ticks;
660 	struct list_head *p, *ack_list_head;
661 	unsigned long flags;
662 	int use_tasklet = 0;
663 
664 	if (timer == NULL)
665 		return;
666 
667 	spin_lock_irqsave(&timer->lock, flags);
668 
669 	/* remember the current resolution */
670 	if (timer->hw.c_resolution)
671 		resolution = timer->hw.c_resolution(timer);
672 	else
673 		resolution = timer->hw.resolution;
674 
675 	/* loop for all active instances
676 	 * Here we cannot use list_for_each_entry because the active_list of a
677 	 * processed instance is relinked to done_list_head before the callback
678 	 * is called.
679 	 */
680 	list_for_each_entry_safe(ti, tmp, &timer->active_list_head,
681 				 active_list) {
682 		if (!(ti->flags & SNDRV_TIMER_IFLG_RUNNING))
683 			continue;
684 		ti->pticks += ticks_left;
685 		ti->resolution = resolution;
686 		if (ti->cticks < ticks_left)
687 			ti->cticks = 0;
688 		else
689 			ti->cticks -= ticks_left;
690 		if (ti->cticks) /* not expired */
691 			continue;
692 		if (ti->flags & SNDRV_TIMER_IFLG_AUTO) {
693 			ti->cticks = ti->ticks;
694 		} else {
695 			ti->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
696 			if (--timer->running)
697 				list_del(&ti->active_list);
698 		}
699 		if ((timer->hw.flags & SNDRV_TIMER_HW_TASKLET) ||
700 		    (ti->flags & SNDRV_TIMER_IFLG_FAST))
701 			ack_list_head = &timer->ack_list_head;
702 		else
703 			ack_list_head = &timer->sack_list_head;
704 		if (list_empty(&ti->ack_list))
705 			list_add_tail(&ti->ack_list, ack_list_head);
706 		list_for_each_entry(ts, &ti->slave_active_head, active_list) {
707 			ts->pticks = ti->pticks;
708 			ts->resolution = resolution;
709 			if (list_empty(&ts->ack_list))
710 				list_add_tail(&ts->ack_list, ack_list_head);
711 		}
712 	}
713 	if (timer->flags & SNDRV_TIMER_FLG_RESCHED)
714 		snd_timer_reschedule(timer, timer->sticks);
715 	if (timer->running) {
716 		if (timer->hw.flags & SNDRV_TIMER_HW_STOP) {
717 			timer->hw.stop(timer);
718 			timer->flags |= SNDRV_TIMER_FLG_CHANGE;
719 		}
720 		if (!(timer->hw.flags & SNDRV_TIMER_HW_AUTO) ||
721 		    (timer->flags & SNDRV_TIMER_FLG_CHANGE)) {
722 			/* restart timer */
723 			timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
724 			timer->hw.start(timer);
725 		}
726 	} else {
727 		timer->hw.stop(timer);
728 	}
729 
730 	/* now process all fast callbacks */
731 	while (!list_empty(&timer->ack_list_head)) {
732 		p = timer->ack_list_head.next;		/* get first item */
733 		ti = list_entry(p, struct snd_timer_instance, ack_list);
734 
735 		/* remove from ack_list and make empty */
736 		list_del_init(p);
737 
738 		ticks = ti->pticks;
739 		ti->pticks = 0;
740 
741 		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
742 		spin_unlock(&timer->lock);
743 		if (ti->callback)
744 			ti->callback(ti, resolution, ticks);
745 		spin_lock(&timer->lock);
746 		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
747 	}
748 
749 	/* do we have any slow callbacks? */
750 	use_tasklet = !list_empty(&timer->sack_list_head);
751 	spin_unlock_irqrestore(&timer->lock, flags);
752 
753 	if (use_tasklet)
754 		tasklet_schedule(&timer->task_queue);
755 }
756 
757 /*
758 
759  */
760 
761 int snd_timer_new(struct snd_card *card, char *id, struct snd_timer_id *tid,
762 		  struct snd_timer **rtimer)
763 {
764 	struct snd_timer *timer;
765 	int err;
766 	static struct snd_device_ops ops = {
767 		.dev_free = snd_timer_dev_free,
768 		.dev_register = snd_timer_dev_register,
769 		.dev_disconnect = snd_timer_dev_disconnect,
770 	};
771 
772 	if (snd_BUG_ON(!tid))
773 		return -EINVAL;
774 	if (rtimer)
775 		*rtimer = NULL;
776 	timer = kzalloc(sizeof(*timer), GFP_KERNEL);
777 	if (timer == NULL) {
778 		pr_err("ALSA: timer: cannot allocate\n");
779 		return -ENOMEM;
780 	}
781 	timer->tmr_class = tid->dev_class;
782 	timer->card = card;
783 	timer->tmr_device = tid->device;
784 	timer->tmr_subdevice = tid->subdevice;
785 	if (id)
786 		strlcpy(timer->id, id, sizeof(timer->id));
787 	INIT_LIST_HEAD(&timer->device_list);
788 	INIT_LIST_HEAD(&timer->open_list_head);
789 	INIT_LIST_HEAD(&timer->active_list_head);
790 	INIT_LIST_HEAD(&timer->ack_list_head);
791 	INIT_LIST_HEAD(&timer->sack_list_head);
792 	spin_lock_init(&timer->lock);
793 	tasklet_init(&timer->task_queue, snd_timer_tasklet,
794 		     (unsigned long)timer);
795 	if (card != NULL) {
796 		timer->module = card->module;
797 		err = snd_device_new(card, SNDRV_DEV_TIMER, timer, &ops);
798 		if (err < 0) {
799 			snd_timer_free(timer);
800 			return err;
801 		}
802 	}
803 	if (rtimer)
804 		*rtimer = timer;
805 	return 0;
806 }
807 
808 static int snd_timer_free(struct snd_timer *timer)
809 {
810 	if (!timer)
811 		return 0;
812 
813 	mutex_lock(&register_mutex);
814 	if (! list_empty(&timer->open_list_head)) {
815 		struct list_head *p, *n;
816 		struct snd_timer_instance *ti;
817 		pr_warn("ALSA: timer %p is busy?\n", timer);
818 		list_for_each_safe(p, n, &timer->open_list_head) {
819 			list_del_init(p);
820 			ti = list_entry(p, struct snd_timer_instance, open_list);
821 			ti->timer = NULL;
822 		}
823 	}
824 	list_del(&timer->device_list);
825 	mutex_unlock(&register_mutex);
826 
827 	if (timer->private_free)
828 		timer->private_free(timer);
829 	kfree(timer);
830 	return 0;
831 }
832 
833 static int snd_timer_dev_free(struct snd_device *device)
834 {
835 	struct snd_timer *timer = device->device_data;
836 	return snd_timer_free(timer);
837 }
838 
839 static int snd_timer_dev_register(struct snd_device *dev)
840 {
841 	struct snd_timer *timer = dev->device_data;
842 	struct snd_timer *timer1;
843 
844 	if (snd_BUG_ON(!timer || !timer->hw.start || !timer->hw.stop))
845 		return -ENXIO;
846 	if (!(timer->hw.flags & SNDRV_TIMER_HW_SLAVE) &&
847 	    !timer->hw.resolution && timer->hw.c_resolution == NULL)
848 	    	return -EINVAL;
849 
850 	mutex_lock(&register_mutex);
851 	list_for_each_entry(timer1, &snd_timer_list, device_list) {
852 		if (timer1->tmr_class > timer->tmr_class)
853 			break;
854 		if (timer1->tmr_class < timer->tmr_class)
855 			continue;
856 		if (timer1->card && timer->card) {
857 			if (timer1->card->number > timer->card->number)
858 				break;
859 			if (timer1->card->number < timer->card->number)
860 				continue;
861 		}
862 		if (timer1->tmr_device > timer->tmr_device)
863 			break;
864 		if (timer1->tmr_device < timer->tmr_device)
865 			continue;
866 		if (timer1->tmr_subdevice > timer->tmr_subdevice)
867 			break;
868 		if (timer1->tmr_subdevice < timer->tmr_subdevice)
869 			continue;
870 		/* conflicts.. */
871 		mutex_unlock(&register_mutex);
872 		return -EBUSY;
873 	}
874 	list_add_tail(&timer->device_list, &timer1->device_list);
875 	mutex_unlock(&register_mutex);
876 	return 0;
877 }
878 
879 static int snd_timer_dev_disconnect(struct snd_device *device)
880 {
881 	struct snd_timer *timer = device->device_data;
882 	mutex_lock(&register_mutex);
883 	list_del_init(&timer->device_list);
884 	mutex_unlock(&register_mutex);
885 	return 0;
886 }
887 
888 void snd_timer_notify(struct snd_timer *timer, int event, struct timespec *tstamp)
889 {
890 	unsigned long flags;
891 	unsigned long resolution = 0;
892 	struct snd_timer_instance *ti, *ts;
893 
894 	if (! (timer->hw.flags & SNDRV_TIMER_HW_SLAVE))
895 		return;
896 	if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_MSTART ||
897 		       event > SNDRV_TIMER_EVENT_MRESUME))
898 		return;
899 	spin_lock_irqsave(&timer->lock, flags);
900 	if (event == SNDRV_TIMER_EVENT_MSTART ||
901 	    event == SNDRV_TIMER_EVENT_MCONTINUE ||
902 	    event == SNDRV_TIMER_EVENT_MRESUME) {
903 		if (timer->hw.c_resolution)
904 			resolution = timer->hw.c_resolution(timer);
905 		else
906 			resolution = timer->hw.resolution;
907 	}
908 	list_for_each_entry(ti, &timer->active_list_head, active_list) {
909 		if (ti->ccallback)
910 			ti->ccallback(ti, event, tstamp, resolution);
911 		list_for_each_entry(ts, &ti->slave_active_head, active_list)
912 			if (ts->ccallback)
913 				ts->ccallback(ts, event, tstamp, resolution);
914 	}
915 	spin_unlock_irqrestore(&timer->lock, flags);
916 }
917 
918 /*
919  * exported functions for global timers
920  */
921 int snd_timer_global_new(char *id, int device, struct snd_timer **rtimer)
922 {
923 	struct snd_timer_id tid;
924 
925 	tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
926 	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
927 	tid.card = -1;
928 	tid.device = device;
929 	tid.subdevice = 0;
930 	return snd_timer_new(NULL, id, &tid, rtimer);
931 }
932 
933 int snd_timer_global_free(struct snd_timer *timer)
934 {
935 	return snd_timer_free(timer);
936 }
937 
938 int snd_timer_global_register(struct snd_timer *timer)
939 {
940 	struct snd_device dev;
941 
942 	memset(&dev, 0, sizeof(dev));
943 	dev.device_data = timer;
944 	return snd_timer_dev_register(&dev);
945 }
946 
947 /*
948  *  System timer
949  */
950 
951 struct snd_timer_system_private {
952 	struct timer_list tlist;
953 	unsigned long last_expires;
954 	unsigned long last_jiffies;
955 	unsigned long correction;
956 };
957 
958 static void snd_timer_s_function(unsigned long data)
959 {
960 	struct snd_timer *timer = (struct snd_timer *)data;
961 	struct snd_timer_system_private *priv = timer->private_data;
962 	unsigned long jiff = jiffies;
963 	if (time_after(jiff, priv->last_expires))
964 		priv->correction += (long)jiff - (long)priv->last_expires;
965 	snd_timer_interrupt(timer, (long)jiff - (long)priv->last_jiffies);
966 }
967 
968 static int snd_timer_s_start(struct snd_timer * timer)
969 {
970 	struct snd_timer_system_private *priv;
971 	unsigned long njiff;
972 
973 	priv = (struct snd_timer_system_private *) timer->private_data;
974 	njiff = (priv->last_jiffies = jiffies);
975 	if (priv->correction > timer->sticks - 1) {
976 		priv->correction -= timer->sticks - 1;
977 		njiff++;
978 	} else {
979 		njiff += timer->sticks - priv->correction;
980 		priv->correction = 0;
981 	}
982 	priv->last_expires = priv->tlist.expires = njiff;
983 	add_timer(&priv->tlist);
984 	return 0;
985 }
986 
987 static int snd_timer_s_stop(struct snd_timer * timer)
988 {
989 	struct snd_timer_system_private *priv;
990 	unsigned long jiff;
991 
992 	priv = (struct snd_timer_system_private *) timer->private_data;
993 	del_timer(&priv->tlist);
994 	jiff = jiffies;
995 	if (time_before(jiff, priv->last_expires))
996 		timer->sticks = priv->last_expires - jiff;
997 	else
998 		timer->sticks = 1;
999 	priv->correction = 0;
1000 	return 0;
1001 }
1002 
1003 static struct snd_timer_hardware snd_timer_system =
1004 {
1005 	.flags =	SNDRV_TIMER_HW_FIRST | SNDRV_TIMER_HW_TASKLET,
1006 	.resolution =	1000000000L / HZ,
1007 	.ticks =	10000000L,
1008 	.start =	snd_timer_s_start,
1009 	.stop =		snd_timer_s_stop
1010 };
1011 
1012 static void snd_timer_free_system(struct snd_timer *timer)
1013 {
1014 	kfree(timer->private_data);
1015 }
1016 
1017 static int snd_timer_register_system(void)
1018 {
1019 	struct snd_timer *timer;
1020 	struct snd_timer_system_private *priv;
1021 	int err;
1022 
1023 	err = snd_timer_global_new("system", SNDRV_TIMER_GLOBAL_SYSTEM, &timer);
1024 	if (err < 0)
1025 		return err;
1026 	strcpy(timer->name, "system timer");
1027 	timer->hw = snd_timer_system;
1028 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1029 	if (priv == NULL) {
1030 		snd_timer_free(timer);
1031 		return -ENOMEM;
1032 	}
1033 	init_timer(&priv->tlist);
1034 	priv->tlist.function = snd_timer_s_function;
1035 	priv->tlist.data = (unsigned long) timer;
1036 	timer->private_data = priv;
1037 	timer->private_free = snd_timer_free_system;
1038 	return snd_timer_global_register(timer);
1039 }
1040 
1041 #ifdef CONFIG_PROC_FS
1042 /*
1043  *  Info interface
1044  */
1045 
1046 static void snd_timer_proc_read(struct snd_info_entry *entry,
1047 				struct snd_info_buffer *buffer)
1048 {
1049 	struct snd_timer *timer;
1050 	struct snd_timer_instance *ti;
1051 
1052 	mutex_lock(&register_mutex);
1053 	list_for_each_entry(timer, &snd_timer_list, device_list) {
1054 		switch (timer->tmr_class) {
1055 		case SNDRV_TIMER_CLASS_GLOBAL:
1056 			snd_iprintf(buffer, "G%i: ", timer->tmr_device);
1057 			break;
1058 		case SNDRV_TIMER_CLASS_CARD:
1059 			snd_iprintf(buffer, "C%i-%i: ",
1060 				    timer->card->number, timer->tmr_device);
1061 			break;
1062 		case SNDRV_TIMER_CLASS_PCM:
1063 			snd_iprintf(buffer, "P%i-%i-%i: ", timer->card->number,
1064 				    timer->tmr_device, timer->tmr_subdevice);
1065 			break;
1066 		default:
1067 			snd_iprintf(buffer, "?%i-%i-%i-%i: ", timer->tmr_class,
1068 				    timer->card ? timer->card->number : -1,
1069 				    timer->tmr_device, timer->tmr_subdevice);
1070 		}
1071 		snd_iprintf(buffer, "%s :", timer->name);
1072 		if (timer->hw.resolution)
1073 			snd_iprintf(buffer, " %lu.%03luus (%lu ticks)",
1074 				    timer->hw.resolution / 1000,
1075 				    timer->hw.resolution % 1000,
1076 				    timer->hw.ticks);
1077 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
1078 			snd_iprintf(buffer, " SLAVE");
1079 		snd_iprintf(buffer, "\n");
1080 		list_for_each_entry(ti, &timer->open_list_head, open_list)
1081 			snd_iprintf(buffer, "  Client %s : %s\n",
1082 				    ti->owner ? ti->owner : "unknown",
1083 				    ti->flags & (SNDRV_TIMER_IFLG_START |
1084 						 SNDRV_TIMER_IFLG_RUNNING)
1085 				    ? "running" : "stopped");
1086 	}
1087 	mutex_unlock(&register_mutex);
1088 }
1089 
1090 static struct snd_info_entry *snd_timer_proc_entry;
1091 
1092 static void __init snd_timer_proc_init(void)
1093 {
1094 	struct snd_info_entry *entry;
1095 
1096 	entry = snd_info_create_module_entry(THIS_MODULE, "timers", NULL);
1097 	if (entry != NULL) {
1098 		entry->c.text.read = snd_timer_proc_read;
1099 		if (snd_info_register(entry) < 0) {
1100 			snd_info_free_entry(entry);
1101 			entry = NULL;
1102 		}
1103 	}
1104 	snd_timer_proc_entry = entry;
1105 }
1106 
1107 static void __exit snd_timer_proc_done(void)
1108 {
1109 	snd_info_free_entry(snd_timer_proc_entry);
1110 }
1111 #else /* !CONFIG_PROC_FS */
1112 #define snd_timer_proc_init()
1113 #define snd_timer_proc_done()
1114 #endif
1115 
1116 /*
1117  *  USER SPACE interface
1118  */
1119 
1120 static void snd_timer_user_interrupt(struct snd_timer_instance *timeri,
1121 				     unsigned long resolution,
1122 				     unsigned long ticks)
1123 {
1124 	struct snd_timer_user *tu = timeri->callback_data;
1125 	struct snd_timer_read *r;
1126 	int prev;
1127 
1128 	spin_lock(&tu->qlock);
1129 	if (tu->qused > 0) {
1130 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1131 		r = &tu->queue[prev];
1132 		if (r->resolution == resolution) {
1133 			r->ticks += ticks;
1134 			goto __wake;
1135 		}
1136 	}
1137 	if (tu->qused >= tu->queue_size) {
1138 		tu->overrun++;
1139 	} else {
1140 		r = &tu->queue[tu->qtail++];
1141 		tu->qtail %= tu->queue_size;
1142 		r->resolution = resolution;
1143 		r->ticks = ticks;
1144 		tu->qused++;
1145 	}
1146       __wake:
1147 	spin_unlock(&tu->qlock);
1148 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1149 	wake_up(&tu->qchange_sleep);
1150 }
1151 
1152 static void snd_timer_user_append_to_tqueue(struct snd_timer_user *tu,
1153 					    struct snd_timer_tread *tread)
1154 {
1155 	if (tu->qused >= tu->queue_size) {
1156 		tu->overrun++;
1157 	} else {
1158 		memcpy(&tu->tqueue[tu->qtail++], tread, sizeof(*tread));
1159 		tu->qtail %= tu->queue_size;
1160 		tu->qused++;
1161 	}
1162 }
1163 
1164 static void snd_timer_user_ccallback(struct snd_timer_instance *timeri,
1165 				     int event,
1166 				     struct timespec *tstamp,
1167 				     unsigned long resolution)
1168 {
1169 	struct snd_timer_user *tu = timeri->callback_data;
1170 	struct snd_timer_tread r1;
1171 	unsigned long flags;
1172 
1173 	if (event >= SNDRV_TIMER_EVENT_START &&
1174 	    event <= SNDRV_TIMER_EVENT_PAUSE)
1175 		tu->tstamp = *tstamp;
1176 	if ((tu->filter & (1 << event)) == 0 || !tu->tread)
1177 		return;
1178 	r1.event = event;
1179 	r1.tstamp = *tstamp;
1180 	r1.val = resolution;
1181 	spin_lock_irqsave(&tu->qlock, flags);
1182 	snd_timer_user_append_to_tqueue(tu, &r1);
1183 	spin_unlock_irqrestore(&tu->qlock, flags);
1184 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1185 	wake_up(&tu->qchange_sleep);
1186 }
1187 
1188 static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
1189 				      unsigned long resolution,
1190 				      unsigned long ticks)
1191 {
1192 	struct snd_timer_user *tu = timeri->callback_data;
1193 	struct snd_timer_tread *r, r1;
1194 	struct timespec tstamp;
1195 	int prev, append = 0;
1196 
1197 	memset(&tstamp, 0, sizeof(tstamp));
1198 	spin_lock(&tu->qlock);
1199 	if ((tu->filter & ((1 << SNDRV_TIMER_EVENT_RESOLUTION) |
1200 			   (1 << SNDRV_TIMER_EVENT_TICK))) == 0) {
1201 		spin_unlock(&tu->qlock);
1202 		return;
1203 	}
1204 	if (tu->last_resolution != resolution || ticks > 0) {
1205 		if (timer_tstamp_monotonic)
1206 			ktime_get_ts(&tstamp);
1207 		else
1208 			getnstimeofday(&tstamp);
1209 	}
1210 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_RESOLUTION)) &&
1211 	    tu->last_resolution != resolution) {
1212 		r1.event = SNDRV_TIMER_EVENT_RESOLUTION;
1213 		r1.tstamp = tstamp;
1214 		r1.val = resolution;
1215 		snd_timer_user_append_to_tqueue(tu, &r1);
1216 		tu->last_resolution = resolution;
1217 		append++;
1218 	}
1219 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_TICK)) == 0)
1220 		goto __wake;
1221 	if (ticks == 0)
1222 		goto __wake;
1223 	if (tu->qused > 0) {
1224 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1225 		r = &tu->tqueue[prev];
1226 		if (r->event == SNDRV_TIMER_EVENT_TICK) {
1227 			r->tstamp = tstamp;
1228 			r->val += ticks;
1229 			append++;
1230 			goto __wake;
1231 		}
1232 	}
1233 	r1.event = SNDRV_TIMER_EVENT_TICK;
1234 	r1.tstamp = tstamp;
1235 	r1.val = ticks;
1236 	snd_timer_user_append_to_tqueue(tu, &r1);
1237 	append++;
1238       __wake:
1239 	spin_unlock(&tu->qlock);
1240 	if (append == 0)
1241 		return;
1242 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1243 	wake_up(&tu->qchange_sleep);
1244 }
1245 
1246 static int snd_timer_user_open(struct inode *inode, struct file *file)
1247 {
1248 	struct snd_timer_user *tu;
1249 	int err;
1250 
1251 	err = nonseekable_open(inode, file);
1252 	if (err < 0)
1253 		return err;
1254 
1255 	tu = kzalloc(sizeof(*tu), GFP_KERNEL);
1256 	if (tu == NULL)
1257 		return -ENOMEM;
1258 	spin_lock_init(&tu->qlock);
1259 	init_waitqueue_head(&tu->qchange_sleep);
1260 	mutex_init(&tu->tread_sem);
1261 	tu->ticks = 1;
1262 	tu->queue_size = 128;
1263 	tu->queue = kmalloc(tu->queue_size * sizeof(struct snd_timer_read),
1264 			    GFP_KERNEL);
1265 	if (tu->queue == NULL) {
1266 		kfree(tu);
1267 		return -ENOMEM;
1268 	}
1269 	file->private_data = tu;
1270 	return 0;
1271 }
1272 
1273 static int snd_timer_user_release(struct inode *inode, struct file *file)
1274 {
1275 	struct snd_timer_user *tu;
1276 
1277 	if (file->private_data) {
1278 		tu = file->private_data;
1279 		file->private_data = NULL;
1280 		if (tu->timeri)
1281 			snd_timer_close(tu->timeri);
1282 		kfree(tu->queue);
1283 		kfree(tu->tqueue);
1284 		kfree(tu);
1285 	}
1286 	return 0;
1287 }
1288 
1289 static void snd_timer_user_zero_id(struct snd_timer_id *id)
1290 {
1291 	id->dev_class = SNDRV_TIMER_CLASS_NONE;
1292 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1293 	id->card = -1;
1294 	id->device = -1;
1295 	id->subdevice = -1;
1296 }
1297 
1298 static void snd_timer_user_copy_id(struct snd_timer_id *id, struct snd_timer *timer)
1299 {
1300 	id->dev_class = timer->tmr_class;
1301 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1302 	id->card = timer->card ? timer->card->number : -1;
1303 	id->device = timer->tmr_device;
1304 	id->subdevice = timer->tmr_subdevice;
1305 }
1306 
1307 static int snd_timer_user_next_device(struct snd_timer_id __user *_tid)
1308 {
1309 	struct snd_timer_id id;
1310 	struct snd_timer *timer;
1311 	struct list_head *p;
1312 
1313 	if (copy_from_user(&id, _tid, sizeof(id)))
1314 		return -EFAULT;
1315 	mutex_lock(&register_mutex);
1316 	if (id.dev_class < 0) {		/* first item */
1317 		if (list_empty(&snd_timer_list))
1318 			snd_timer_user_zero_id(&id);
1319 		else {
1320 			timer = list_entry(snd_timer_list.next,
1321 					   struct snd_timer, device_list);
1322 			snd_timer_user_copy_id(&id, timer);
1323 		}
1324 	} else {
1325 		switch (id.dev_class) {
1326 		case SNDRV_TIMER_CLASS_GLOBAL:
1327 			id.device = id.device < 0 ? 0 : id.device + 1;
1328 			list_for_each(p, &snd_timer_list) {
1329 				timer = list_entry(p, struct snd_timer, device_list);
1330 				if (timer->tmr_class > SNDRV_TIMER_CLASS_GLOBAL) {
1331 					snd_timer_user_copy_id(&id, timer);
1332 					break;
1333 				}
1334 				if (timer->tmr_device >= id.device) {
1335 					snd_timer_user_copy_id(&id, timer);
1336 					break;
1337 				}
1338 			}
1339 			if (p == &snd_timer_list)
1340 				snd_timer_user_zero_id(&id);
1341 			break;
1342 		case SNDRV_TIMER_CLASS_CARD:
1343 		case SNDRV_TIMER_CLASS_PCM:
1344 			if (id.card < 0) {
1345 				id.card = 0;
1346 			} else {
1347 				if (id.card < 0) {
1348 					id.card = 0;
1349 				} else {
1350 					if (id.device < 0) {
1351 						id.device = 0;
1352 					} else {
1353 						if (id.subdevice < 0) {
1354 							id.subdevice = 0;
1355 						} else {
1356 							id.subdevice++;
1357 						}
1358 					}
1359 				}
1360 			}
1361 			list_for_each(p, &snd_timer_list) {
1362 				timer = list_entry(p, struct snd_timer, device_list);
1363 				if (timer->tmr_class > id.dev_class) {
1364 					snd_timer_user_copy_id(&id, timer);
1365 					break;
1366 				}
1367 				if (timer->tmr_class < id.dev_class)
1368 					continue;
1369 				if (timer->card->number > id.card) {
1370 					snd_timer_user_copy_id(&id, timer);
1371 					break;
1372 				}
1373 				if (timer->card->number < id.card)
1374 					continue;
1375 				if (timer->tmr_device > id.device) {
1376 					snd_timer_user_copy_id(&id, timer);
1377 					break;
1378 				}
1379 				if (timer->tmr_device < id.device)
1380 					continue;
1381 				if (timer->tmr_subdevice > id.subdevice) {
1382 					snd_timer_user_copy_id(&id, timer);
1383 					break;
1384 				}
1385 				if (timer->tmr_subdevice < id.subdevice)
1386 					continue;
1387 				snd_timer_user_copy_id(&id, timer);
1388 				break;
1389 			}
1390 			if (p == &snd_timer_list)
1391 				snd_timer_user_zero_id(&id);
1392 			break;
1393 		default:
1394 			snd_timer_user_zero_id(&id);
1395 		}
1396 	}
1397 	mutex_unlock(&register_mutex);
1398 	if (copy_to_user(_tid, &id, sizeof(*_tid)))
1399 		return -EFAULT;
1400 	return 0;
1401 }
1402 
1403 static int snd_timer_user_ginfo(struct file *file,
1404 				struct snd_timer_ginfo __user *_ginfo)
1405 {
1406 	struct snd_timer_ginfo *ginfo;
1407 	struct snd_timer_id tid;
1408 	struct snd_timer *t;
1409 	struct list_head *p;
1410 	int err = 0;
1411 
1412 	ginfo = memdup_user(_ginfo, sizeof(*ginfo));
1413 	if (IS_ERR(ginfo))
1414 		return PTR_ERR(ginfo);
1415 
1416 	tid = ginfo->tid;
1417 	memset(ginfo, 0, sizeof(*ginfo));
1418 	ginfo->tid = tid;
1419 	mutex_lock(&register_mutex);
1420 	t = snd_timer_find(&tid);
1421 	if (t != NULL) {
1422 		ginfo->card = t->card ? t->card->number : -1;
1423 		if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1424 			ginfo->flags |= SNDRV_TIMER_FLG_SLAVE;
1425 		strlcpy(ginfo->id, t->id, sizeof(ginfo->id));
1426 		strlcpy(ginfo->name, t->name, sizeof(ginfo->name));
1427 		ginfo->resolution = t->hw.resolution;
1428 		if (t->hw.resolution_min > 0) {
1429 			ginfo->resolution_min = t->hw.resolution_min;
1430 			ginfo->resolution_max = t->hw.resolution_max;
1431 		}
1432 		list_for_each(p, &t->open_list_head) {
1433 			ginfo->clients++;
1434 		}
1435 	} else {
1436 		err = -ENODEV;
1437 	}
1438 	mutex_unlock(&register_mutex);
1439 	if (err >= 0 && copy_to_user(_ginfo, ginfo, sizeof(*ginfo)))
1440 		err = -EFAULT;
1441 	kfree(ginfo);
1442 	return err;
1443 }
1444 
1445 static int snd_timer_user_gparams(struct file *file,
1446 				  struct snd_timer_gparams __user *_gparams)
1447 {
1448 	struct snd_timer_gparams gparams;
1449 	struct snd_timer *t;
1450 	int err;
1451 
1452 	if (copy_from_user(&gparams, _gparams, sizeof(gparams)))
1453 		return -EFAULT;
1454 	mutex_lock(&register_mutex);
1455 	t = snd_timer_find(&gparams.tid);
1456 	if (!t) {
1457 		err = -ENODEV;
1458 		goto _error;
1459 	}
1460 	if (!list_empty(&t->open_list_head)) {
1461 		err = -EBUSY;
1462 		goto _error;
1463 	}
1464 	if (!t->hw.set_period) {
1465 		err = -ENOSYS;
1466 		goto _error;
1467 	}
1468 	err = t->hw.set_period(t, gparams.period_num, gparams.period_den);
1469 _error:
1470 	mutex_unlock(&register_mutex);
1471 	return err;
1472 }
1473 
1474 static int snd_timer_user_gstatus(struct file *file,
1475 				  struct snd_timer_gstatus __user *_gstatus)
1476 {
1477 	struct snd_timer_gstatus gstatus;
1478 	struct snd_timer_id tid;
1479 	struct snd_timer *t;
1480 	int err = 0;
1481 
1482 	if (copy_from_user(&gstatus, _gstatus, sizeof(gstatus)))
1483 		return -EFAULT;
1484 	tid = gstatus.tid;
1485 	memset(&gstatus, 0, sizeof(gstatus));
1486 	gstatus.tid = tid;
1487 	mutex_lock(&register_mutex);
1488 	t = snd_timer_find(&tid);
1489 	if (t != NULL) {
1490 		if (t->hw.c_resolution)
1491 			gstatus.resolution = t->hw.c_resolution(t);
1492 		else
1493 			gstatus.resolution = t->hw.resolution;
1494 		if (t->hw.precise_resolution) {
1495 			t->hw.precise_resolution(t, &gstatus.resolution_num,
1496 						 &gstatus.resolution_den);
1497 		} else {
1498 			gstatus.resolution_num = gstatus.resolution;
1499 			gstatus.resolution_den = 1000000000uL;
1500 		}
1501 	} else {
1502 		err = -ENODEV;
1503 	}
1504 	mutex_unlock(&register_mutex);
1505 	if (err >= 0 && copy_to_user(_gstatus, &gstatus, sizeof(gstatus)))
1506 		err = -EFAULT;
1507 	return err;
1508 }
1509 
1510 static int snd_timer_user_tselect(struct file *file,
1511 				  struct snd_timer_select __user *_tselect)
1512 {
1513 	struct snd_timer_user *tu;
1514 	struct snd_timer_select tselect;
1515 	char str[32];
1516 	int err = 0;
1517 
1518 	tu = file->private_data;
1519 	mutex_lock(&tu->tread_sem);
1520 	if (tu->timeri) {
1521 		snd_timer_close(tu->timeri);
1522 		tu->timeri = NULL;
1523 	}
1524 	if (copy_from_user(&tselect, _tselect, sizeof(tselect))) {
1525 		err = -EFAULT;
1526 		goto __err;
1527 	}
1528 	sprintf(str, "application %i", current->pid);
1529 	if (tselect.id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
1530 		tselect.id.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION;
1531 	err = snd_timer_open(&tu->timeri, str, &tselect.id, current->pid);
1532 	if (err < 0)
1533 		goto __err;
1534 
1535 	kfree(tu->queue);
1536 	tu->queue = NULL;
1537 	kfree(tu->tqueue);
1538 	tu->tqueue = NULL;
1539 	if (tu->tread) {
1540 		tu->tqueue = kmalloc(tu->queue_size * sizeof(struct snd_timer_tread),
1541 				     GFP_KERNEL);
1542 		if (tu->tqueue == NULL)
1543 			err = -ENOMEM;
1544 	} else {
1545 		tu->queue = kmalloc(tu->queue_size * sizeof(struct snd_timer_read),
1546 				    GFP_KERNEL);
1547 		if (tu->queue == NULL)
1548 			err = -ENOMEM;
1549 	}
1550 
1551       	if (err < 0) {
1552 		snd_timer_close(tu->timeri);
1553       		tu->timeri = NULL;
1554       	} else {
1555 		tu->timeri->flags |= SNDRV_TIMER_IFLG_FAST;
1556 		tu->timeri->callback = tu->tread
1557 			? snd_timer_user_tinterrupt : snd_timer_user_interrupt;
1558 		tu->timeri->ccallback = snd_timer_user_ccallback;
1559 		tu->timeri->callback_data = (void *)tu;
1560 	}
1561 
1562       __err:
1563       	mutex_unlock(&tu->tread_sem);
1564 	return err;
1565 }
1566 
1567 static int snd_timer_user_info(struct file *file,
1568 			       struct snd_timer_info __user *_info)
1569 {
1570 	struct snd_timer_user *tu;
1571 	struct snd_timer_info *info;
1572 	struct snd_timer *t;
1573 	int err = 0;
1574 
1575 	tu = file->private_data;
1576 	if (!tu->timeri)
1577 		return -EBADFD;
1578 	t = tu->timeri->timer;
1579 	if (!t)
1580 		return -EBADFD;
1581 
1582 	info = kzalloc(sizeof(*info), GFP_KERNEL);
1583 	if (! info)
1584 		return -ENOMEM;
1585 	info->card = t->card ? t->card->number : -1;
1586 	if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1587 		info->flags |= SNDRV_TIMER_FLG_SLAVE;
1588 	strlcpy(info->id, t->id, sizeof(info->id));
1589 	strlcpy(info->name, t->name, sizeof(info->name));
1590 	info->resolution = t->hw.resolution;
1591 	if (copy_to_user(_info, info, sizeof(*_info)))
1592 		err = -EFAULT;
1593 	kfree(info);
1594 	return err;
1595 }
1596 
1597 static int snd_timer_user_params(struct file *file,
1598 				 struct snd_timer_params __user *_params)
1599 {
1600 	struct snd_timer_user *tu;
1601 	struct snd_timer_params params;
1602 	struct snd_timer *t;
1603 	struct snd_timer_read *tr;
1604 	struct snd_timer_tread *ttr;
1605 	int err;
1606 
1607 	tu = file->private_data;
1608 	if (!tu->timeri)
1609 		return -EBADFD;
1610 	t = tu->timeri->timer;
1611 	if (!t)
1612 		return -EBADFD;
1613 	if (copy_from_user(&params, _params, sizeof(params)))
1614 		return -EFAULT;
1615 	if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE) && params.ticks < 1) {
1616 		err = -EINVAL;
1617 		goto _end;
1618 	}
1619 	if (params.queue_size > 0 &&
1620 	    (params.queue_size < 32 || params.queue_size > 1024)) {
1621 		err = -EINVAL;
1622 		goto _end;
1623 	}
1624 	if (params.filter & ~((1<<SNDRV_TIMER_EVENT_RESOLUTION)|
1625 			      (1<<SNDRV_TIMER_EVENT_TICK)|
1626 			      (1<<SNDRV_TIMER_EVENT_START)|
1627 			      (1<<SNDRV_TIMER_EVENT_STOP)|
1628 			      (1<<SNDRV_TIMER_EVENT_CONTINUE)|
1629 			      (1<<SNDRV_TIMER_EVENT_PAUSE)|
1630 			      (1<<SNDRV_TIMER_EVENT_SUSPEND)|
1631 			      (1<<SNDRV_TIMER_EVENT_RESUME)|
1632 			      (1<<SNDRV_TIMER_EVENT_MSTART)|
1633 			      (1<<SNDRV_TIMER_EVENT_MSTOP)|
1634 			      (1<<SNDRV_TIMER_EVENT_MCONTINUE)|
1635 			      (1<<SNDRV_TIMER_EVENT_MPAUSE)|
1636 			      (1<<SNDRV_TIMER_EVENT_MSUSPEND)|
1637 			      (1<<SNDRV_TIMER_EVENT_MRESUME))) {
1638 		err = -EINVAL;
1639 		goto _end;
1640 	}
1641 	snd_timer_stop(tu->timeri);
1642 	spin_lock_irq(&t->lock);
1643 	tu->timeri->flags &= ~(SNDRV_TIMER_IFLG_AUTO|
1644 			       SNDRV_TIMER_IFLG_EXCLUSIVE|
1645 			       SNDRV_TIMER_IFLG_EARLY_EVENT);
1646 	if (params.flags & SNDRV_TIMER_PSFLG_AUTO)
1647 		tu->timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1648 	if (params.flags & SNDRV_TIMER_PSFLG_EXCLUSIVE)
1649 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EXCLUSIVE;
1650 	if (params.flags & SNDRV_TIMER_PSFLG_EARLY_EVENT)
1651 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EARLY_EVENT;
1652 	spin_unlock_irq(&t->lock);
1653 	if (params.queue_size > 0 &&
1654 	    (unsigned int)tu->queue_size != params.queue_size) {
1655 		if (tu->tread) {
1656 			ttr = kmalloc(params.queue_size * sizeof(*ttr),
1657 				      GFP_KERNEL);
1658 			if (ttr) {
1659 				kfree(tu->tqueue);
1660 				tu->queue_size = params.queue_size;
1661 				tu->tqueue = ttr;
1662 			}
1663 		} else {
1664 			tr = kmalloc(params.queue_size * sizeof(*tr),
1665 				     GFP_KERNEL);
1666 			if (tr) {
1667 				kfree(tu->queue);
1668 				tu->queue_size = params.queue_size;
1669 				tu->queue = tr;
1670 			}
1671 		}
1672 	}
1673 	tu->qhead = tu->qtail = tu->qused = 0;
1674 	if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
1675 		if (tu->tread) {
1676 			struct snd_timer_tread tread;
1677 			tread.event = SNDRV_TIMER_EVENT_EARLY;
1678 			tread.tstamp.tv_sec = 0;
1679 			tread.tstamp.tv_nsec = 0;
1680 			tread.val = 0;
1681 			snd_timer_user_append_to_tqueue(tu, &tread);
1682 		} else {
1683 			struct snd_timer_read *r = &tu->queue[0];
1684 			r->resolution = 0;
1685 			r->ticks = 0;
1686 			tu->qused++;
1687 			tu->qtail++;
1688 		}
1689 	}
1690 	tu->filter = params.filter;
1691 	tu->ticks = params.ticks;
1692 	err = 0;
1693  _end:
1694 	if (copy_to_user(_params, &params, sizeof(params)))
1695 		return -EFAULT;
1696 	return err;
1697 }
1698 
1699 static int snd_timer_user_status(struct file *file,
1700 				 struct snd_timer_status __user *_status)
1701 {
1702 	struct snd_timer_user *tu;
1703 	struct snd_timer_status status;
1704 
1705 	tu = file->private_data;
1706 	if (!tu->timeri)
1707 		return -EBADFD;
1708 	memset(&status, 0, sizeof(status));
1709 	status.tstamp = tu->tstamp;
1710 	status.resolution = snd_timer_resolution(tu->timeri);
1711 	status.lost = tu->timeri->lost;
1712 	status.overrun = tu->overrun;
1713 	spin_lock_irq(&tu->qlock);
1714 	status.queue = tu->qused;
1715 	spin_unlock_irq(&tu->qlock);
1716 	if (copy_to_user(_status, &status, sizeof(status)))
1717 		return -EFAULT;
1718 	return 0;
1719 }
1720 
1721 static int snd_timer_user_start(struct file *file)
1722 {
1723 	int err;
1724 	struct snd_timer_user *tu;
1725 
1726 	tu = file->private_data;
1727 	if (!tu->timeri)
1728 		return -EBADFD;
1729 	snd_timer_stop(tu->timeri);
1730 	tu->timeri->lost = 0;
1731 	tu->last_resolution = 0;
1732 	return (err = snd_timer_start(tu->timeri, tu->ticks)) < 0 ? err : 0;
1733 }
1734 
1735 static int snd_timer_user_stop(struct file *file)
1736 {
1737 	int err;
1738 	struct snd_timer_user *tu;
1739 
1740 	tu = file->private_data;
1741 	if (!tu->timeri)
1742 		return -EBADFD;
1743 	return (err = snd_timer_stop(tu->timeri)) < 0 ? err : 0;
1744 }
1745 
1746 static int snd_timer_user_continue(struct file *file)
1747 {
1748 	int err;
1749 	struct snd_timer_user *tu;
1750 
1751 	tu = file->private_data;
1752 	if (!tu->timeri)
1753 		return -EBADFD;
1754 	tu->timeri->lost = 0;
1755 	return (err = snd_timer_continue(tu->timeri)) < 0 ? err : 0;
1756 }
1757 
1758 static int snd_timer_user_pause(struct file *file)
1759 {
1760 	int err;
1761 	struct snd_timer_user *tu;
1762 
1763 	tu = file->private_data;
1764 	if (!tu->timeri)
1765 		return -EBADFD;
1766 	return (err = snd_timer_pause(tu->timeri)) < 0 ? err : 0;
1767 }
1768 
1769 enum {
1770 	SNDRV_TIMER_IOCTL_START_OLD = _IO('T', 0x20),
1771 	SNDRV_TIMER_IOCTL_STOP_OLD = _IO('T', 0x21),
1772 	SNDRV_TIMER_IOCTL_CONTINUE_OLD = _IO('T', 0x22),
1773 	SNDRV_TIMER_IOCTL_PAUSE_OLD = _IO('T', 0x23),
1774 };
1775 
1776 static long snd_timer_user_ioctl(struct file *file, unsigned int cmd,
1777 				 unsigned long arg)
1778 {
1779 	struct snd_timer_user *tu;
1780 	void __user *argp = (void __user *)arg;
1781 	int __user *p = argp;
1782 
1783 	tu = file->private_data;
1784 	switch (cmd) {
1785 	case SNDRV_TIMER_IOCTL_PVERSION:
1786 		return put_user(SNDRV_TIMER_VERSION, p) ? -EFAULT : 0;
1787 	case SNDRV_TIMER_IOCTL_NEXT_DEVICE:
1788 		return snd_timer_user_next_device(argp);
1789 	case SNDRV_TIMER_IOCTL_TREAD:
1790 	{
1791 		int xarg;
1792 
1793 		mutex_lock(&tu->tread_sem);
1794 		if (tu->timeri)	{	/* too late */
1795 			mutex_unlock(&tu->tread_sem);
1796 			return -EBUSY;
1797 		}
1798 		if (get_user(xarg, p)) {
1799 			mutex_unlock(&tu->tread_sem);
1800 			return -EFAULT;
1801 		}
1802 		tu->tread = xarg ? 1 : 0;
1803 		mutex_unlock(&tu->tread_sem);
1804 		return 0;
1805 	}
1806 	case SNDRV_TIMER_IOCTL_GINFO:
1807 		return snd_timer_user_ginfo(file, argp);
1808 	case SNDRV_TIMER_IOCTL_GPARAMS:
1809 		return snd_timer_user_gparams(file, argp);
1810 	case SNDRV_TIMER_IOCTL_GSTATUS:
1811 		return snd_timer_user_gstatus(file, argp);
1812 	case SNDRV_TIMER_IOCTL_SELECT:
1813 		return snd_timer_user_tselect(file, argp);
1814 	case SNDRV_TIMER_IOCTL_INFO:
1815 		return snd_timer_user_info(file, argp);
1816 	case SNDRV_TIMER_IOCTL_PARAMS:
1817 		return snd_timer_user_params(file, argp);
1818 	case SNDRV_TIMER_IOCTL_STATUS:
1819 		return snd_timer_user_status(file, argp);
1820 	case SNDRV_TIMER_IOCTL_START:
1821 	case SNDRV_TIMER_IOCTL_START_OLD:
1822 		return snd_timer_user_start(file);
1823 	case SNDRV_TIMER_IOCTL_STOP:
1824 	case SNDRV_TIMER_IOCTL_STOP_OLD:
1825 		return snd_timer_user_stop(file);
1826 	case SNDRV_TIMER_IOCTL_CONTINUE:
1827 	case SNDRV_TIMER_IOCTL_CONTINUE_OLD:
1828 		return snd_timer_user_continue(file);
1829 	case SNDRV_TIMER_IOCTL_PAUSE:
1830 	case SNDRV_TIMER_IOCTL_PAUSE_OLD:
1831 		return snd_timer_user_pause(file);
1832 	}
1833 	return -ENOTTY;
1834 }
1835 
1836 static int snd_timer_user_fasync(int fd, struct file * file, int on)
1837 {
1838 	struct snd_timer_user *tu;
1839 
1840 	tu = file->private_data;
1841 	return fasync_helper(fd, file, on, &tu->fasync);
1842 }
1843 
1844 static ssize_t snd_timer_user_read(struct file *file, char __user *buffer,
1845 				   size_t count, loff_t *offset)
1846 {
1847 	struct snd_timer_user *tu;
1848 	long result = 0, unit;
1849 	int err = 0;
1850 
1851 	tu = file->private_data;
1852 	unit = tu->tread ? sizeof(struct snd_timer_tread) : sizeof(struct snd_timer_read);
1853 	spin_lock_irq(&tu->qlock);
1854 	while ((long)count - result >= unit) {
1855 		while (!tu->qused) {
1856 			wait_queue_t wait;
1857 
1858 			if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1859 				err = -EAGAIN;
1860 				break;
1861 			}
1862 
1863 			set_current_state(TASK_INTERRUPTIBLE);
1864 			init_waitqueue_entry(&wait, current);
1865 			add_wait_queue(&tu->qchange_sleep, &wait);
1866 
1867 			spin_unlock_irq(&tu->qlock);
1868 			schedule();
1869 			spin_lock_irq(&tu->qlock);
1870 
1871 			remove_wait_queue(&tu->qchange_sleep, &wait);
1872 
1873 			if (signal_pending(current)) {
1874 				err = -ERESTARTSYS;
1875 				break;
1876 			}
1877 		}
1878 
1879 		spin_unlock_irq(&tu->qlock);
1880 		if (err < 0)
1881 			goto _error;
1882 
1883 		if (tu->tread) {
1884 			if (copy_to_user(buffer, &tu->tqueue[tu->qhead++],
1885 					 sizeof(struct snd_timer_tread))) {
1886 				err = -EFAULT;
1887 				goto _error;
1888 			}
1889 		} else {
1890 			if (copy_to_user(buffer, &tu->queue[tu->qhead++],
1891 					 sizeof(struct snd_timer_read))) {
1892 				err = -EFAULT;
1893 				goto _error;
1894 			}
1895 		}
1896 
1897 		tu->qhead %= tu->queue_size;
1898 
1899 		result += unit;
1900 		buffer += unit;
1901 
1902 		spin_lock_irq(&tu->qlock);
1903 		tu->qused--;
1904 	}
1905 	spin_unlock_irq(&tu->qlock);
1906  _error:
1907 	return result > 0 ? result : err;
1908 }
1909 
1910 static unsigned int snd_timer_user_poll(struct file *file, poll_table * wait)
1911 {
1912         unsigned int mask;
1913         struct snd_timer_user *tu;
1914 
1915         tu = file->private_data;
1916 
1917         poll_wait(file, &tu->qchange_sleep, wait);
1918 
1919 	mask = 0;
1920 	if (tu->qused)
1921 		mask |= POLLIN | POLLRDNORM;
1922 
1923 	return mask;
1924 }
1925 
1926 #ifdef CONFIG_COMPAT
1927 #include "timer_compat.c"
1928 #else
1929 #define snd_timer_user_ioctl_compat	NULL
1930 #endif
1931 
1932 static const struct file_operations snd_timer_f_ops =
1933 {
1934 	.owner =	THIS_MODULE,
1935 	.read =		snd_timer_user_read,
1936 	.open =		snd_timer_user_open,
1937 	.release =	snd_timer_user_release,
1938 	.llseek =	no_llseek,
1939 	.poll =		snd_timer_user_poll,
1940 	.unlocked_ioctl =	snd_timer_user_ioctl,
1941 	.compat_ioctl =	snd_timer_user_ioctl_compat,
1942 	.fasync = 	snd_timer_user_fasync,
1943 };
1944 
1945 /*
1946  *  ENTRY functions
1947  */
1948 
1949 static int __init alsa_timer_init(void)
1950 {
1951 	int err;
1952 
1953 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
1954 	snd_oss_info_register(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1,
1955 			      "system timer");
1956 #endif
1957 
1958 	if ((err = snd_timer_register_system()) < 0)
1959 		pr_err("ALSA: unable to register system timer (%i)\n", err);
1960 	if ((err = snd_register_device(SNDRV_DEVICE_TYPE_TIMER, NULL, 0,
1961 				       &snd_timer_f_ops, NULL, "timer")) < 0)
1962 		pr_err("ALSA: unable to register timer device (%i)\n", err);
1963 	snd_timer_proc_init();
1964 	return 0;
1965 }
1966 
1967 static void __exit alsa_timer_exit(void)
1968 {
1969 	struct list_head *p, *n;
1970 
1971 	snd_unregister_device(SNDRV_DEVICE_TYPE_TIMER, NULL, 0);
1972 	/* unregister the system timer */
1973 	list_for_each_safe(p, n, &snd_timer_list) {
1974 		struct snd_timer *timer = list_entry(p, struct snd_timer, device_list);
1975 		snd_timer_free(timer);
1976 	}
1977 	snd_timer_proc_done();
1978 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
1979 	snd_oss_info_unregister(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1);
1980 #endif
1981 }
1982 
1983 module_init(alsa_timer_init)
1984 module_exit(alsa_timer_exit)
1985 
1986 EXPORT_SYMBOL(snd_timer_open);
1987 EXPORT_SYMBOL(snd_timer_close);
1988 EXPORT_SYMBOL(snd_timer_resolution);
1989 EXPORT_SYMBOL(snd_timer_start);
1990 EXPORT_SYMBOL(snd_timer_stop);
1991 EXPORT_SYMBOL(snd_timer_continue);
1992 EXPORT_SYMBOL(snd_timer_pause);
1993 EXPORT_SYMBOL(snd_timer_new);
1994 EXPORT_SYMBOL(snd_timer_notify);
1995 EXPORT_SYMBOL(snd_timer_global_new);
1996 EXPORT_SYMBOL(snd_timer_global_free);
1997 EXPORT_SYMBOL(snd_timer_global_register);
1998 EXPORT_SYMBOL(snd_timer_interrupt);
1999