xref: /openbmc/linux/sound/core/timer.c (revision 6391503b)
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 	bool disconnected;
69 	struct snd_timer_read *queue;
70 	struct snd_timer_tread *tqueue;
71 	spinlock_t qlock;
72 	unsigned long last_resolution;
73 	unsigned int filter;
74 	struct timespec tstamp;		/* trigger tstamp */
75 	wait_queue_head_t qchange_sleep;
76 	struct fasync_struct *fasync;
77 	struct mutex ioctl_lock;
78 };
79 
80 /* list of timers */
81 static LIST_HEAD(snd_timer_list);
82 
83 /* list of slave instances */
84 static LIST_HEAD(snd_timer_slave_list);
85 
86 /* lock for slave active lists */
87 static DEFINE_SPINLOCK(slave_active_lock);
88 
89 static DEFINE_MUTEX(register_mutex);
90 
91 static int snd_timer_free(struct snd_timer *timer);
92 static int snd_timer_dev_free(struct snd_device *device);
93 static int snd_timer_dev_register(struct snd_device *device);
94 static int snd_timer_dev_disconnect(struct snd_device *device);
95 
96 static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left);
97 
98 /*
99  * create a timer instance with the given owner string.
100  * when timer is not NULL, increments the module counter
101  */
102 static struct snd_timer_instance *snd_timer_instance_new(char *owner,
103 							 struct snd_timer *timer)
104 {
105 	struct snd_timer_instance *timeri;
106 	timeri = kzalloc(sizeof(*timeri), GFP_KERNEL);
107 	if (timeri == NULL)
108 		return NULL;
109 	timeri->owner = kstrdup(owner, GFP_KERNEL);
110 	if (! timeri->owner) {
111 		kfree(timeri);
112 		return NULL;
113 	}
114 	INIT_LIST_HEAD(&timeri->open_list);
115 	INIT_LIST_HEAD(&timeri->active_list);
116 	INIT_LIST_HEAD(&timeri->ack_list);
117 	INIT_LIST_HEAD(&timeri->slave_list_head);
118 	INIT_LIST_HEAD(&timeri->slave_active_head);
119 
120 	timeri->timer = timer;
121 	if (timer && !try_module_get(timer->module)) {
122 		kfree(timeri->owner);
123 		kfree(timeri);
124 		return NULL;
125 	}
126 
127 	return timeri;
128 }
129 
130 /*
131  * find a timer instance from the given timer id
132  */
133 static struct snd_timer *snd_timer_find(struct snd_timer_id *tid)
134 {
135 	struct snd_timer *timer = NULL;
136 
137 	list_for_each_entry(timer, &snd_timer_list, device_list) {
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_MODULES
155 
156 static void snd_timer_request(struct snd_timer_id *tid)
157 {
158 	switch (tid->dev_class) {
159 	case SNDRV_TIMER_CLASS_GLOBAL:
160 		if (tid->device < timer_limit)
161 			request_module("snd-timer-%i", tid->device);
162 		break;
163 	case SNDRV_TIMER_CLASS_CARD:
164 	case SNDRV_TIMER_CLASS_PCM:
165 		if (tid->card < snd_ecards_limit)
166 			request_module("snd-card-%i", tid->card);
167 		break;
168 	default:
169 		break;
170 	}
171 }
172 
173 #endif
174 
175 /*
176  * look for a master instance matching with the slave id of the given slave.
177  * when found, relink the open_link of the slave.
178  *
179  * call this with register_mutex down.
180  */
181 static void snd_timer_check_slave(struct snd_timer_instance *slave)
182 {
183 	struct snd_timer *timer;
184 	struct snd_timer_instance *master;
185 
186 	/* FIXME: it's really dumb to look up all entries.. */
187 	list_for_each_entry(timer, &snd_timer_list, device_list) {
188 		list_for_each_entry(master, &timer->open_list_head, open_list) {
189 			if (slave->slave_class == master->slave_class &&
190 			    slave->slave_id == master->slave_id) {
191 				list_move_tail(&slave->open_list,
192 					       &master->slave_list_head);
193 				spin_lock_irq(&slave_active_lock);
194 				slave->master = master;
195 				slave->timer = master->timer;
196 				spin_unlock_irq(&slave_active_lock);
197 				return;
198 			}
199 		}
200 	}
201 }
202 
203 /*
204  * look for slave instances matching with the slave id of the given master.
205  * when found, relink the open_link of slaves.
206  *
207  * call this with register_mutex down.
208  */
209 static void snd_timer_check_master(struct snd_timer_instance *master)
210 {
211 	struct snd_timer_instance *slave, *tmp;
212 
213 	/* check all pending slaves */
214 	list_for_each_entry_safe(slave, tmp, &snd_timer_slave_list, open_list) {
215 		if (slave->slave_class == master->slave_class &&
216 		    slave->slave_id == master->slave_id) {
217 			list_move_tail(&slave->open_list, &master->slave_list_head);
218 			spin_lock_irq(&slave_active_lock);
219 			spin_lock(&master->timer->lock);
220 			slave->master = master;
221 			slave->timer = master->timer;
222 			if (slave->flags & SNDRV_TIMER_IFLG_RUNNING)
223 				list_add_tail(&slave->active_list,
224 					      &master->slave_active_head);
225 			spin_unlock(&master->timer->lock);
226 			spin_unlock_irq(&slave_active_lock);
227 		}
228 	}
229 }
230 
231 /*
232  * open a timer instance
233  * when opening a master, the slave id must be here given.
234  */
235 int snd_timer_open(struct snd_timer_instance **ti,
236 		   char *owner, struct snd_timer_id *tid,
237 		   unsigned int slave_id)
238 {
239 	struct snd_timer *timer;
240 	struct snd_timer_instance *timeri = NULL;
241 
242 	if (tid->dev_class == SNDRV_TIMER_CLASS_SLAVE) {
243 		/* open a slave instance */
244 		if (tid->dev_sclass <= SNDRV_TIMER_SCLASS_NONE ||
245 		    tid->dev_sclass > SNDRV_TIMER_SCLASS_OSS_SEQUENCER) {
246 			pr_debug("ALSA: timer: invalid slave class %i\n",
247 				 tid->dev_sclass);
248 			return -EINVAL;
249 		}
250 		mutex_lock(&register_mutex);
251 		timeri = snd_timer_instance_new(owner, NULL);
252 		if (!timeri) {
253 			mutex_unlock(&register_mutex);
254 			return -ENOMEM;
255 		}
256 		timeri->slave_class = tid->dev_sclass;
257 		timeri->slave_id = tid->device;
258 		timeri->flags |= SNDRV_TIMER_IFLG_SLAVE;
259 		list_add_tail(&timeri->open_list, &snd_timer_slave_list);
260 		snd_timer_check_slave(timeri);
261 		mutex_unlock(&register_mutex);
262 		*ti = timeri;
263 		return 0;
264 	}
265 
266 	/* open a master instance */
267 	mutex_lock(&register_mutex);
268 	timer = snd_timer_find(tid);
269 #ifdef CONFIG_MODULES
270 	if (!timer) {
271 		mutex_unlock(&register_mutex);
272 		snd_timer_request(tid);
273 		mutex_lock(&register_mutex);
274 		timer = snd_timer_find(tid);
275 	}
276 #endif
277 	if (!timer) {
278 		mutex_unlock(&register_mutex);
279 		return -ENODEV;
280 	}
281 	if (!list_empty(&timer->open_list_head)) {
282 		timeri = list_entry(timer->open_list_head.next,
283 				    struct snd_timer_instance, open_list);
284 		if (timeri->flags & SNDRV_TIMER_IFLG_EXCLUSIVE) {
285 			mutex_unlock(&register_mutex);
286 			return -EBUSY;
287 		}
288 	}
289 	timeri = snd_timer_instance_new(owner, timer);
290 	if (!timeri) {
291 		mutex_unlock(&register_mutex);
292 		return -ENOMEM;
293 	}
294 	/* take a card refcount for safe disconnection */
295 	if (timer->card)
296 		get_device(&timer->card->card_dev);
297 	timeri->slave_class = tid->dev_sclass;
298 	timeri->slave_id = slave_id;
299 	if (list_empty(&timer->open_list_head) && timer->hw.open)
300 		timer->hw.open(timer);
301 	list_add_tail(&timeri->open_list, &timer->open_list_head);
302 	snd_timer_check_master(timeri);
303 	mutex_unlock(&register_mutex);
304 	*ti = timeri;
305 	return 0;
306 }
307 
308 static int _snd_timer_stop(struct snd_timer_instance *timeri, int event);
309 
310 /*
311  * close a timer instance
312  */
313 int snd_timer_close(struct snd_timer_instance *timeri)
314 {
315 	struct snd_timer *timer = NULL;
316 	struct snd_timer_instance *slave, *tmp;
317 
318 	if (snd_BUG_ON(!timeri))
319 		return -ENXIO;
320 
321 	/* force to stop the timer */
322 	snd_timer_stop(timeri);
323 
324 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) {
325 		/* wait, until the active callback is finished */
326 		spin_lock_irq(&slave_active_lock);
327 		while (timeri->flags & SNDRV_TIMER_IFLG_CALLBACK) {
328 			spin_unlock_irq(&slave_active_lock);
329 			udelay(10);
330 			spin_lock_irq(&slave_active_lock);
331 		}
332 		spin_unlock_irq(&slave_active_lock);
333 		mutex_lock(&register_mutex);
334 		list_del(&timeri->open_list);
335 		mutex_unlock(&register_mutex);
336 	} else {
337 		timer = timeri->timer;
338 		if (snd_BUG_ON(!timer))
339 			goto out;
340 		/* wait, until the active callback is finished */
341 		spin_lock_irq(&timer->lock);
342 		while (timeri->flags & SNDRV_TIMER_IFLG_CALLBACK) {
343 			spin_unlock_irq(&timer->lock);
344 			udelay(10);
345 			spin_lock_irq(&timer->lock);
346 		}
347 		spin_unlock_irq(&timer->lock);
348 		mutex_lock(&register_mutex);
349 		list_del(&timeri->open_list);
350 		if (list_empty(&timer->open_list_head) &&
351 		    timer->hw.close)
352 			timer->hw.close(timer);
353 		/* remove slave links */
354 		spin_lock_irq(&slave_active_lock);
355 		spin_lock(&timer->lock);
356 		list_for_each_entry_safe(slave, tmp, &timeri->slave_list_head,
357 					 open_list) {
358 			list_move_tail(&slave->open_list, &snd_timer_slave_list);
359 			slave->master = NULL;
360 			slave->timer = NULL;
361 			list_del_init(&slave->ack_list);
362 			list_del_init(&slave->active_list);
363 		}
364 		spin_unlock(&timer->lock);
365 		spin_unlock_irq(&slave_active_lock);
366 		/* release a card refcount for safe disconnection */
367 		if (timer->card)
368 			put_device(&timer->card->card_dev);
369 		mutex_unlock(&register_mutex);
370 	}
371  out:
372 	if (timeri->private_free)
373 		timeri->private_free(timeri);
374 	kfree(timeri->owner);
375 	kfree(timeri);
376 	if (timer)
377 		module_put(timer->module);
378 	return 0;
379 }
380 
381 unsigned long snd_timer_resolution(struct snd_timer_instance *timeri)
382 {
383 	struct snd_timer * timer;
384 
385 	if (timeri == NULL)
386 		return 0;
387 	if ((timer = timeri->timer) != NULL) {
388 		if (timer->hw.c_resolution)
389 			return timer->hw.c_resolution(timer);
390 		return timer->hw.resolution;
391 	}
392 	return 0;
393 }
394 
395 static void snd_timer_notify1(struct snd_timer_instance *ti, int event)
396 {
397 	struct snd_timer *timer;
398 	unsigned long flags;
399 	unsigned long resolution = 0;
400 	struct snd_timer_instance *ts;
401 	struct timespec tstamp;
402 
403 	if (timer_tstamp_monotonic)
404 		ktime_get_ts(&tstamp);
405 	else
406 		getnstimeofday(&tstamp);
407 	if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_START ||
408 		       event > SNDRV_TIMER_EVENT_PAUSE))
409 		return;
410 	if (event == SNDRV_TIMER_EVENT_START ||
411 	    event == SNDRV_TIMER_EVENT_CONTINUE)
412 		resolution = snd_timer_resolution(ti);
413 	if (ti->ccallback)
414 		ti->ccallback(ti, event, &tstamp, resolution);
415 	if (ti->flags & SNDRV_TIMER_IFLG_SLAVE)
416 		return;
417 	timer = ti->timer;
418 	if (timer == NULL)
419 		return;
420 	if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
421 		return;
422 	spin_lock_irqsave(&timer->lock, flags);
423 	list_for_each_entry(ts, &ti->slave_active_head, active_list)
424 		if (ts->ccallback)
425 			ts->ccallback(ti, event + 100, &tstamp, resolution);
426 	spin_unlock_irqrestore(&timer->lock, flags);
427 }
428 
429 static int snd_timer_start1(struct snd_timer *timer, struct snd_timer_instance *timeri,
430 			    unsigned long sticks)
431 {
432 	list_move_tail(&timeri->active_list, &timer->active_list_head);
433 	if (timer->running) {
434 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
435 			goto __start_now;
436 		timer->flags |= SNDRV_TIMER_FLG_RESCHED;
437 		timeri->flags |= SNDRV_TIMER_IFLG_START;
438 		return 1;	/* delayed start */
439 	} else {
440 		timer->sticks = sticks;
441 		timer->hw.start(timer);
442 	      __start_now:
443 		timer->running++;
444 		timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
445 		return 0;
446 	}
447 }
448 
449 static int snd_timer_start_slave(struct snd_timer_instance *timeri)
450 {
451 	unsigned long flags;
452 
453 	spin_lock_irqsave(&slave_active_lock, flags);
454 	timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
455 	if (timeri->master && timeri->timer) {
456 		spin_lock(&timeri->timer->lock);
457 		list_add_tail(&timeri->active_list,
458 			      &timeri->master->slave_active_head);
459 		spin_unlock(&timeri->timer->lock);
460 	}
461 	spin_unlock_irqrestore(&slave_active_lock, flags);
462 	return 1; /* delayed start */
463 }
464 
465 /*
466  *  start the timer instance
467  */
468 int snd_timer_start(struct snd_timer_instance *timeri, unsigned int ticks)
469 {
470 	struct snd_timer *timer;
471 	int result = -EINVAL;
472 	unsigned long flags;
473 
474 	if (timeri == NULL || ticks < 1)
475 		return -EINVAL;
476 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) {
477 		result = snd_timer_start_slave(timeri);
478 		snd_timer_notify1(timeri, SNDRV_TIMER_EVENT_START);
479 		return result;
480 	}
481 	timer = timeri->timer;
482 	if (timer == NULL)
483 		return -EINVAL;
484 	if (timer->card && timer->card->shutdown)
485 		return -ENODEV;
486 	spin_lock_irqsave(&timer->lock, flags);
487 	timeri->ticks = timeri->cticks = ticks;
488 	timeri->pticks = 0;
489 	result = snd_timer_start1(timer, timeri, ticks);
490 	spin_unlock_irqrestore(&timer->lock, flags);
491 	snd_timer_notify1(timeri, SNDRV_TIMER_EVENT_START);
492 	return result;
493 }
494 
495 static int _snd_timer_stop(struct snd_timer_instance *timeri, int event)
496 {
497 	struct snd_timer *timer;
498 	unsigned long flags;
499 
500 	if (snd_BUG_ON(!timeri))
501 		return -ENXIO;
502 
503 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE) {
504 		spin_lock_irqsave(&slave_active_lock, flags);
505 		timeri->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
506 		list_del_init(&timeri->ack_list);
507 		list_del_init(&timeri->active_list);
508 		spin_unlock_irqrestore(&slave_active_lock, flags);
509 		goto __end;
510 	}
511 	timer = timeri->timer;
512 	if (!timer)
513 		return -EINVAL;
514 	spin_lock_irqsave(&timer->lock, flags);
515 	list_del_init(&timeri->ack_list);
516 	list_del_init(&timeri->active_list);
517 	if (timer->card && timer->card->shutdown) {
518 		spin_unlock_irqrestore(&timer->lock, flags);
519 		return 0;
520 	}
521 	if ((timeri->flags & SNDRV_TIMER_IFLG_RUNNING) &&
522 	    !(--timer->running)) {
523 		timer->hw.stop(timer);
524 		if (timer->flags & SNDRV_TIMER_FLG_RESCHED) {
525 			timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
526 			snd_timer_reschedule(timer, 0);
527 			if (timer->flags & SNDRV_TIMER_FLG_CHANGE) {
528 				timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
529 				timer->hw.start(timer);
530 			}
531 		}
532 	}
533 	timeri->flags &= ~(SNDRV_TIMER_IFLG_RUNNING | SNDRV_TIMER_IFLG_START);
534 	spin_unlock_irqrestore(&timer->lock, flags);
535       __end:
536 	if (event != SNDRV_TIMER_EVENT_RESOLUTION)
537 		snd_timer_notify1(timeri, event);
538 	return 0;
539 }
540 
541 /*
542  * stop the timer instance.
543  *
544  * do not call this from the timer callback!
545  */
546 int snd_timer_stop(struct snd_timer_instance *timeri)
547 {
548 	struct snd_timer *timer;
549 	unsigned long flags;
550 	int err;
551 
552 	err = _snd_timer_stop(timeri, SNDRV_TIMER_EVENT_STOP);
553 	if (err < 0)
554 		return err;
555 	timer = timeri->timer;
556 	if (!timer)
557 		return -EINVAL;
558 	spin_lock_irqsave(&timer->lock, flags);
559 	timeri->cticks = timeri->ticks;
560 	timeri->pticks = 0;
561 	spin_unlock_irqrestore(&timer->lock, flags);
562 	return 0;
563 }
564 
565 /*
566  * start again..  the tick is kept.
567  */
568 int snd_timer_continue(struct snd_timer_instance *timeri)
569 {
570 	struct snd_timer *timer;
571 	int result = -EINVAL;
572 	unsigned long flags;
573 
574 	if (timeri == NULL)
575 		return result;
576 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
577 		return snd_timer_start_slave(timeri);
578 	timer = timeri->timer;
579 	if (! timer)
580 		return -EINVAL;
581 	if (timer->card && timer->card->shutdown)
582 		return -ENODEV;
583 	spin_lock_irqsave(&timer->lock, flags);
584 	if (!timeri->cticks)
585 		timeri->cticks = 1;
586 	timeri->pticks = 0;
587 	result = snd_timer_start1(timer, timeri, timer->sticks);
588 	spin_unlock_irqrestore(&timer->lock, flags);
589 	snd_timer_notify1(timeri, SNDRV_TIMER_EVENT_CONTINUE);
590 	return result;
591 }
592 
593 /*
594  * pause.. remember the ticks left
595  */
596 int snd_timer_pause(struct snd_timer_instance * timeri)
597 {
598 	return _snd_timer_stop(timeri, SNDRV_TIMER_EVENT_PAUSE);
599 }
600 
601 /*
602  * reschedule the timer
603  *
604  * start pending instances and check the scheduling ticks.
605  * when the scheduling ticks is changed set CHANGE flag to reprogram the timer.
606  */
607 static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left)
608 {
609 	struct snd_timer_instance *ti;
610 	unsigned long ticks = ~0UL;
611 
612 	list_for_each_entry(ti, &timer->active_list_head, active_list) {
613 		if (ti->flags & SNDRV_TIMER_IFLG_START) {
614 			ti->flags &= ~SNDRV_TIMER_IFLG_START;
615 			ti->flags |= SNDRV_TIMER_IFLG_RUNNING;
616 			timer->running++;
617 		}
618 		if (ti->flags & SNDRV_TIMER_IFLG_RUNNING) {
619 			if (ticks > ti->cticks)
620 				ticks = ti->cticks;
621 		}
622 	}
623 	if (ticks == ~0UL) {
624 		timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
625 		return;
626 	}
627 	if (ticks > timer->hw.ticks)
628 		ticks = timer->hw.ticks;
629 	if (ticks_left != ticks)
630 		timer->flags |= SNDRV_TIMER_FLG_CHANGE;
631 	timer->sticks = ticks;
632 }
633 
634 /*
635  * timer tasklet
636  *
637  */
638 static void snd_timer_tasklet(unsigned long arg)
639 {
640 	struct snd_timer *timer = (struct snd_timer *) arg;
641 	struct snd_timer_instance *ti;
642 	struct list_head *p;
643 	unsigned long resolution, ticks;
644 	unsigned long flags;
645 
646 	if (timer->card && timer->card->shutdown)
647 		return;
648 
649 	spin_lock_irqsave(&timer->lock, flags);
650 	/* now process all callbacks */
651 	while (!list_empty(&timer->sack_list_head)) {
652 		p = timer->sack_list_head.next;		/* get first item */
653 		ti = list_entry(p, struct snd_timer_instance, ack_list);
654 
655 		/* remove from ack_list and make empty */
656 		list_del_init(p);
657 
658 		ticks = ti->pticks;
659 		ti->pticks = 0;
660 		resolution = ti->resolution;
661 
662 		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
663 		spin_unlock(&timer->lock);
664 		if (ti->callback)
665 			ti->callback(ti, resolution, ticks);
666 		spin_lock(&timer->lock);
667 		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
668 	}
669 	spin_unlock_irqrestore(&timer->lock, flags);
670 }
671 
672 /*
673  * timer interrupt
674  *
675  * ticks_left is usually equal to timer->sticks.
676  *
677  */
678 void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
679 {
680 	struct snd_timer_instance *ti, *ts, *tmp;
681 	unsigned long resolution, ticks;
682 	struct list_head *p, *ack_list_head;
683 	unsigned long flags;
684 	int use_tasklet = 0;
685 
686 	if (timer == NULL)
687 		return;
688 
689 	if (timer->card && timer->card->shutdown)
690 		return;
691 
692 	spin_lock_irqsave(&timer->lock, flags);
693 
694 	/* remember the current resolution */
695 	if (timer->hw.c_resolution)
696 		resolution = timer->hw.c_resolution(timer);
697 	else
698 		resolution = timer->hw.resolution;
699 
700 	/* loop for all active instances
701 	 * Here we cannot use list_for_each_entry because the active_list of a
702 	 * processed instance is relinked to done_list_head before the callback
703 	 * is called.
704 	 */
705 	list_for_each_entry_safe(ti, tmp, &timer->active_list_head,
706 				 active_list) {
707 		if (!(ti->flags & SNDRV_TIMER_IFLG_RUNNING))
708 			continue;
709 		ti->pticks += ticks_left;
710 		ti->resolution = resolution;
711 		if (ti->cticks < ticks_left)
712 			ti->cticks = 0;
713 		else
714 			ti->cticks -= ticks_left;
715 		if (ti->cticks) /* not expired */
716 			continue;
717 		if (ti->flags & SNDRV_TIMER_IFLG_AUTO) {
718 			ti->cticks = ti->ticks;
719 		} else {
720 			ti->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
721 			if (--timer->running)
722 				list_del_init(&ti->active_list);
723 		}
724 		if ((timer->hw.flags & SNDRV_TIMER_HW_TASKLET) ||
725 		    (ti->flags & SNDRV_TIMER_IFLG_FAST))
726 			ack_list_head = &timer->ack_list_head;
727 		else
728 			ack_list_head = &timer->sack_list_head;
729 		if (list_empty(&ti->ack_list))
730 			list_add_tail(&ti->ack_list, ack_list_head);
731 		list_for_each_entry(ts, &ti->slave_active_head, active_list) {
732 			ts->pticks = ti->pticks;
733 			ts->resolution = resolution;
734 			if (list_empty(&ts->ack_list))
735 				list_add_tail(&ts->ack_list, ack_list_head);
736 		}
737 	}
738 	if (timer->flags & SNDRV_TIMER_FLG_RESCHED)
739 		snd_timer_reschedule(timer, timer->sticks);
740 	if (timer->running) {
741 		if (timer->hw.flags & SNDRV_TIMER_HW_STOP) {
742 			timer->hw.stop(timer);
743 			timer->flags |= SNDRV_TIMER_FLG_CHANGE;
744 		}
745 		if (!(timer->hw.flags & SNDRV_TIMER_HW_AUTO) ||
746 		    (timer->flags & SNDRV_TIMER_FLG_CHANGE)) {
747 			/* restart timer */
748 			timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
749 			timer->hw.start(timer);
750 		}
751 	} else {
752 		timer->hw.stop(timer);
753 	}
754 
755 	/* now process all fast callbacks */
756 	while (!list_empty(&timer->ack_list_head)) {
757 		p = timer->ack_list_head.next;		/* get first item */
758 		ti = list_entry(p, struct snd_timer_instance, ack_list);
759 
760 		/* remove from ack_list and make empty */
761 		list_del_init(p);
762 
763 		ticks = ti->pticks;
764 		ti->pticks = 0;
765 
766 		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
767 		spin_unlock(&timer->lock);
768 		if (ti->callback)
769 			ti->callback(ti, resolution, ticks);
770 		spin_lock(&timer->lock);
771 		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
772 	}
773 
774 	/* do we have any slow callbacks? */
775 	use_tasklet = !list_empty(&timer->sack_list_head);
776 	spin_unlock_irqrestore(&timer->lock, flags);
777 
778 	if (use_tasklet)
779 		tasklet_schedule(&timer->task_queue);
780 }
781 
782 /*
783 
784  */
785 
786 int snd_timer_new(struct snd_card *card, char *id, struct snd_timer_id *tid,
787 		  struct snd_timer **rtimer)
788 {
789 	struct snd_timer *timer;
790 	int err;
791 	static struct snd_device_ops ops = {
792 		.dev_free = snd_timer_dev_free,
793 		.dev_register = snd_timer_dev_register,
794 		.dev_disconnect = snd_timer_dev_disconnect,
795 	};
796 
797 	if (snd_BUG_ON(!tid))
798 		return -EINVAL;
799 	if (rtimer)
800 		*rtimer = NULL;
801 	timer = kzalloc(sizeof(*timer), GFP_KERNEL);
802 	if (!timer)
803 		return -ENOMEM;
804 	timer->tmr_class = tid->dev_class;
805 	timer->card = card;
806 	timer->tmr_device = tid->device;
807 	timer->tmr_subdevice = tid->subdevice;
808 	if (id)
809 		strlcpy(timer->id, id, sizeof(timer->id));
810 	INIT_LIST_HEAD(&timer->device_list);
811 	INIT_LIST_HEAD(&timer->open_list_head);
812 	INIT_LIST_HEAD(&timer->active_list_head);
813 	INIT_LIST_HEAD(&timer->ack_list_head);
814 	INIT_LIST_HEAD(&timer->sack_list_head);
815 	spin_lock_init(&timer->lock);
816 	tasklet_init(&timer->task_queue, snd_timer_tasklet,
817 		     (unsigned long)timer);
818 	if (card != NULL) {
819 		timer->module = card->module;
820 		err = snd_device_new(card, SNDRV_DEV_TIMER, timer, &ops);
821 		if (err < 0) {
822 			snd_timer_free(timer);
823 			return err;
824 		}
825 	}
826 	if (rtimer)
827 		*rtimer = timer;
828 	return 0;
829 }
830 
831 static int snd_timer_free(struct snd_timer *timer)
832 {
833 	if (!timer)
834 		return 0;
835 
836 	mutex_lock(&register_mutex);
837 	if (! list_empty(&timer->open_list_head)) {
838 		struct list_head *p, *n;
839 		struct snd_timer_instance *ti;
840 		pr_warn("ALSA: timer %p is busy?\n", timer);
841 		list_for_each_safe(p, n, &timer->open_list_head) {
842 			list_del_init(p);
843 			ti = list_entry(p, struct snd_timer_instance, open_list);
844 			ti->timer = NULL;
845 		}
846 	}
847 	list_del(&timer->device_list);
848 	mutex_unlock(&register_mutex);
849 
850 	if (timer->private_free)
851 		timer->private_free(timer);
852 	kfree(timer);
853 	return 0;
854 }
855 
856 static int snd_timer_dev_free(struct snd_device *device)
857 {
858 	struct snd_timer *timer = device->device_data;
859 	return snd_timer_free(timer);
860 }
861 
862 static int snd_timer_dev_register(struct snd_device *dev)
863 {
864 	struct snd_timer *timer = dev->device_data;
865 	struct snd_timer *timer1;
866 
867 	if (snd_BUG_ON(!timer || !timer->hw.start || !timer->hw.stop))
868 		return -ENXIO;
869 	if (!(timer->hw.flags & SNDRV_TIMER_HW_SLAVE) &&
870 	    !timer->hw.resolution && timer->hw.c_resolution == NULL)
871 	    	return -EINVAL;
872 
873 	mutex_lock(&register_mutex);
874 	list_for_each_entry(timer1, &snd_timer_list, device_list) {
875 		if (timer1->tmr_class > timer->tmr_class)
876 			break;
877 		if (timer1->tmr_class < timer->tmr_class)
878 			continue;
879 		if (timer1->card && timer->card) {
880 			if (timer1->card->number > timer->card->number)
881 				break;
882 			if (timer1->card->number < timer->card->number)
883 				continue;
884 		}
885 		if (timer1->tmr_device > timer->tmr_device)
886 			break;
887 		if (timer1->tmr_device < timer->tmr_device)
888 			continue;
889 		if (timer1->tmr_subdevice > timer->tmr_subdevice)
890 			break;
891 		if (timer1->tmr_subdevice < timer->tmr_subdevice)
892 			continue;
893 		/* conflicts.. */
894 		mutex_unlock(&register_mutex);
895 		return -EBUSY;
896 	}
897 	list_add_tail(&timer->device_list, &timer1->device_list);
898 	mutex_unlock(&register_mutex);
899 	return 0;
900 }
901 
902 static int snd_timer_dev_disconnect(struct snd_device *device)
903 {
904 	struct snd_timer *timer = device->device_data;
905 	struct snd_timer_instance *ti;
906 
907 	mutex_lock(&register_mutex);
908 	list_del_init(&timer->device_list);
909 	/* wake up pending sleepers */
910 	list_for_each_entry(ti, &timer->open_list_head, open_list) {
911 		if (ti->disconnect)
912 			ti->disconnect(ti);
913 	}
914 	mutex_unlock(&register_mutex);
915 	return 0;
916 }
917 
918 void snd_timer_notify(struct snd_timer *timer, int event, struct timespec *tstamp)
919 {
920 	unsigned long flags;
921 	unsigned long resolution = 0;
922 	struct snd_timer_instance *ti, *ts;
923 
924 	if (timer->card && timer->card->shutdown)
925 		return;
926 	if (! (timer->hw.flags & SNDRV_TIMER_HW_SLAVE))
927 		return;
928 	if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_MSTART ||
929 		       event > SNDRV_TIMER_EVENT_MRESUME))
930 		return;
931 	spin_lock_irqsave(&timer->lock, flags);
932 	if (event == SNDRV_TIMER_EVENT_MSTART ||
933 	    event == SNDRV_TIMER_EVENT_MCONTINUE ||
934 	    event == SNDRV_TIMER_EVENT_MRESUME) {
935 		if (timer->hw.c_resolution)
936 			resolution = timer->hw.c_resolution(timer);
937 		else
938 			resolution = timer->hw.resolution;
939 	}
940 	list_for_each_entry(ti, &timer->active_list_head, active_list) {
941 		if (ti->ccallback)
942 			ti->ccallback(ti, event, tstamp, resolution);
943 		list_for_each_entry(ts, &ti->slave_active_head, active_list)
944 			if (ts->ccallback)
945 				ts->ccallback(ts, event, tstamp, resolution);
946 	}
947 	spin_unlock_irqrestore(&timer->lock, flags);
948 }
949 
950 /*
951  * exported functions for global timers
952  */
953 int snd_timer_global_new(char *id, int device, struct snd_timer **rtimer)
954 {
955 	struct snd_timer_id tid;
956 
957 	tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
958 	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
959 	tid.card = -1;
960 	tid.device = device;
961 	tid.subdevice = 0;
962 	return snd_timer_new(NULL, id, &tid, rtimer);
963 }
964 
965 int snd_timer_global_free(struct snd_timer *timer)
966 {
967 	return snd_timer_free(timer);
968 }
969 
970 int snd_timer_global_register(struct snd_timer *timer)
971 {
972 	struct snd_device dev;
973 
974 	memset(&dev, 0, sizeof(dev));
975 	dev.device_data = timer;
976 	return snd_timer_dev_register(&dev);
977 }
978 
979 /*
980  *  System timer
981  */
982 
983 struct snd_timer_system_private {
984 	struct timer_list tlist;
985 	unsigned long last_expires;
986 	unsigned long last_jiffies;
987 	unsigned long correction;
988 };
989 
990 static void snd_timer_s_function(unsigned long data)
991 {
992 	struct snd_timer *timer = (struct snd_timer *)data;
993 	struct snd_timer_system_private *priv = timer->private_data;
994 	unsigned long jiff = jiffies;
995 	if (time_after(jiff, priv->last_expires))
996 		priv->correction += (long)jiff - (long)priv->last_expires;
997 	snd_timer_interrupt(timer, (long)jiff - (long)priv->last_jiffies);
998 }
999 
1000 static int snd_timer_s_start(struct snd_timer * timer)
1001 {
1002 	struct snd_timer_system_private *priv;
1003 	unsigned long njiff;
1004 
1005 	priv = (struct snd_timer_system_private *) timer->private_data;
1006 	njiff = (priv->last_jiffies = jiffies);
1007 	if (priv->correction > timer->sticks - 1) {
1008 		priv->correction -= timer->sticks - 1;
1009 		njiff++;
1010 	} else {
1011 		njiff += timer->sticks - priv->correction;
1012 		priv->correction = 0;
1013 	}
1014 	priv->last_expires = priv->tlist.expires = njiff;
1015 	add_timer(&priv->tlist);
1016 	return 0;
1017 }
1018 
1019 static int snd_timer_s_stop(struct snd_timer * timer)
1020 {
1021 	struct snd_timer_system_private *priv;
1022 	unsigned long jiff;
1023 
1024 	priv = (struct snd_timer_system_private *) timer->private_data;
1025 	del_timer(&priv->tlist);
1026 	jiff = jiffies;
1027 	if (time_before(jiff, priv->last_expires))
1028 		timer->sticks = priv->last_expires - jiff;
1029 	else
1030 		timer->sticks = 1;
1031 	priv->correction = 0;
1032 	return 0;
1033 }
1034 
1035 static struct snd_timer_hardware snd_timer_system =
1036 {
1037 	.flags =	SNDRV_TIMER_HW_FIRST | SNDRV_TIMER_HW_TASKLET,
1038 	.resolution =	1000000000L / HZ,
1039 	.ticks =	10000000L,
1040 	.start =	snd_timer_s_start,
1041 	.stop =		snd_timer_s_stop
1042 };
1043 
1044 static void snd_timer_free_system(struct snd_timer *timer)
1045 {
1046 	kfree(timer->private_data);
1047 }
1048 
1049 static int snd_timer_register_system(void)
1050 {
1051 	struct snd_timer *timer;
1052 	struct snd_timer_system_private *priv;
1053 	int err;
1054 
1055 	err = snd_timer_global_new("system", SNDRV_TIMER_GLOBAL_SYSTEM, &timer);
1056 	if (err < 0)
1057 		return err;
1058 	strcpy(timer->name, "system timer");
1059 	timer->hw = snd_timer_system;
1060 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1061 	if (priv == NULL) {
1062 		snd_timer_free(timer);
1063 		return -ENOMEM;
1064 	}
1065 	setup_timer(&priv->tlist, snd_timer_s_function, (unsigned long) timer);
1066 	timer->private_data = priv;
1067 	timer->private_free = snd_timer_free_system;
1068 	return snd_timer_global_register(timer);
1069 }
1070 
1071 #ifdef CONFIG_SND_PROC_FS
1072 /*
1073  *  Info interface
1074  */
1075 
1076 static void snd_timer_proc_read(struct snd_info_entry *entry,
1077 				struct snd_info_buffer *buffer)
1078 {
1079 	struct snd_timer *timer;
1080 	struct snd_timer_instance *ti;
1081 
1082 	mutex_lock(&register_mutex);
1083 	list_for_each_entry(timer, &snd_timer_list, device_list) {
1084 		if (timer->card && timer->card->shutdown)
1085 			continue;
1086 		switch (timer->tmr_class) {
1087 		case SNDRV_TIMER_CLASS_GLOBAL:
1088 			snd_iprintf(buffer, "G%i: ", timer->tmr_device);
1089 			break;
1090 		case SNDRV_TIMER_CLASS_CARD:
1091 			snd_iprintf(buffer, "C%i-%i: ",
1092 				    timer->card->number, timer->tmr_device);
1093 			break;
1094 		case SNDRV_TIMER_CLASS_PCM:
1095 			snd_iprintf(buffer, "P%i-%i-%i: ", timer->card->number,
1096 				    timer->tmr_device, timer->tmr_subdevice);
1097 			break;
1098 		default:
1099 			snd_iprintf(buffer, "?%i-%i-%i-%i: ", timer->tmr_class,
1100 				    timer->card ? timer->card->number : -1,
1101 				    timer->tmr_device, timer->tmr_subdevice);
1102 		}
1103 		snd_iprintf(buffer, "%s :", timer->name);
1104 		if (timer->hw.resolution)
1105 			snd_iprintf(buffer, " %lu.%03luus (%lu ticks)",
1106 				    timer->hw.resolution / 1000,
1107 				    timer->hw.resolution % 1000,
1108 				    timer->hw.ticks);
1109 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
1110 			snd_iprintf(buffer, " SLAVE");
1111 		snd_iprintf(buffer, "\n");
1112 		list_for_each_entry(ti, &timer->open_list_head, open_list)
1113 			snd_iprintf(buffer, "  Client %s : %s\n",
1114 				    ti->owner ? ti->owner : "unknown",
1115 				    ti->flags & (SNDRV_TIMER_IFLG_START |
1116 						 SNDRV_TIMER_IFLG_RUNNING)
1117 				    ? "running" : "stopped");
1118 	}
1119 	mutex_unlock(&register_mutex);
1120 }
1121 
1122 static struct snd_info_entry *snd_timer_proc_entry;
1123 
1124 static void __init snd_timer_proc_init(void)
1125 {
1126 	struct snd_info_entry *entry;
1127 
1128 	entry = snd_info_create_module_entry(THIS_MODULE, "timers", NULL);
1129 	if (entry != NULL) {
1130 		entry->c.text.read = snd_timer_proc_read;
1131 		if (snd_info_register(entry) < 0) {
1132 			snd_info_free_entry(entry);
1133 			entry = NULL;
1134 		}
1135 	}
1136 	snd_timer_proc_entry = entry;
1137 }
1138 
1139 static void __exit snd_timer_proc_done(void)
1140 {
1141 	snd_info_free_entry(snd_timer_proc_entry);
1142 }
1143 #else /* !CONFIG_SND_PROC_FS */
1144 #define snd_timer_proc_init()
1145 #define snd_timer_proc_done()
1146 #endif
1147 
1148 /*
1149  *  USER SPACE interface
1150  */
1151 
1152 static void snd_timer_user_interrupt(struct snd_timer_instance *timeri,
1153 				     unsigned long resolution,
1154 				     unsigned long ticks)
1155 {
1156 	struct snd_timer_user *tu = timeri->callback_data;
1157 	struct snd_timer_read *r;
1158 	int prev;
1159 
1160 	spin_lock(&tu->qlock);
1161 	if (tu->qused > 0) {
1162 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1163 		r = &tu->queue[prev];
1164 		if (r->resolution == resolution) {
1165 			r->ticks += ticks;
1166 			goto __wake;
1167 		}
1168 	}
1169 	if (tu->qused >= tu->queue_size) {
1170 		tu->overrun++;
1171 	} else {
1172 		r = &tu->queue[tu->qtail++];
1173 		tu->qtail %= tu->queue_size;
1174 		r->resolution = resolution;
1175 		r->ticks = ticks;
1176 		tu->qused++;
1177 	}
1178       __wake:
1179 	spin_unlock(&tu->qlock);
1180 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1181 	wake_up(&tu->qchange_sleep);
1182 }
1183 
1184 static void snd_timer_user_append_to_tqueue(struct snd_timer_user *tu,
1185 					    struct snd_timer_tread *tread)
1186 {
1187 	if (tu->qused >= tu->queue_size) {
1188 		tu->overrun++;
1189 	} else {
1190 		memcpy(&tu->tqueue[tu->qtail++], tread, sizeof(*tread));
1191 		tu->qtail %= tu->queue_size;
1192 		tu->qused++;
1193 	}
1194 }
1195 
1196 static void snd_timer_user_ccallback(struct snd_timer_instance *timeri,
1197 				     int event,
1198 				     struct timespec *tstamp,
1199 				     unsigned long resolution)
1200 {
1201 	struct snd_timer_user *tu = timeri->callback_data;
1202 	struct snd_timer_tread r1;
1203 	unsigned long flags;
1204 
1205 	if (event >= SNDRV_TIMER_EVENT_START &&
1206 	    event <= SNDRV_TIMER_EVENT_PAUSE)
1207 		tu->tstamp = *tstamp;
1208 	if ((tu->filter & (1 << event)) == 0 || !tu->tread)
1209 		return;
1210 	r1.event = event;
1211 	r1.tstamp = *tstamp;
1212 	r1.val = resolution;
1213 	spin_lock_irqsave(&tu->qlock, flags);
1214 	snd_timer_user_append_to_tqueue(tu, &r1);
1215 	spin_unlock_irqrestore(&tu->qlock, flags);
1216 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1217 	wake_up(&tu->qchange_sleep);
1218 }
1219 
1220 static void snd_timer_user_disconnect(struct snd_timer_instance *timeri)
1221 {
1222 	struct snd_timer_user *tu = timeri->callback_data;
1223 
1224 	tu->disconnected = true;
1225 	wake_up(&tu->qchange_sleep);
1226 }
1227 
1228 static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
1229 				      unsigned long resolution,
1230 				      unsigned long ticks)
1231 {
1232 	struct snd_timer_user *tu = timeri->callback_data;
1233 	struct snd_timer_tread *r, r1;
1234 	struct timespec tstamp;
1235 	int prev, append = 0;
1236 
1237 	memset(&tstamp, 0, sizeof(tstamp));
1238 	spin_lock(&tu->qlock);
1239 	if ((tu->filter & ((1 << SNDRV_TIMER_EVENT_RESOLUTION) |
1240 			   (1 << SNDRV_TIMER_EVENT_TICK))) == 0) {
1241 		spin_unlock(&tu->qlock);
1242 		return;
1243 	}
1244 	if (tu->last_resolution != resolution || ticks > 0) {
1245 		if (timer_tstamp_monotonic)
1246 			ktime_get_ts(&tstamp);
1247 		else
1248 			getnstimeofday(&tstamp);
1249 	}
1250 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_RESOLUTION)) &&
1251 	    tu->last_resolution != resolution) {
1252 		r1.event = SNDRV_TIMER_EVENT_RESOLUTION;
1253 		r1.tstamp = tstamp;
1254 		r1.val = resolution;
1255 		snd_timer_user_append_to_tqueue(tu, &r1);
1256 		tu->last_resolution = resolution;
1257 		append++;
1258 	}
1259 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_TICK)) == 0)
1260 		goto __wake;
1261 	if (ticks == 0)
1262 		goto __wake;
1263 	if (tu->qused > 0) {
1264 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1265 		r = &tu->tqueue[prev];
1266 		if (r->event == SNDRV_TIMER_EVENT_TICK) {
1267 			r->tstamp = tstamp;
1268 			r->val += ticks;
1269 			append++;
1270 			goto __wake;
1271 		}
1272 	}
1273 	r1.event = SNDRV_TIMER_EVENT_TICK;
1274 	r1.tstamp = tstamp;
1275 	r1.val = ticks;
1276 	snd_timer_user_append_to_tqueue(tu, &r1);
1277 	append++;
1278       __wake:
1279 	spin_unlock(&tu->qlock);
1280 	if (append == 0)
1281 		return;
1282 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1283 	wake_up(&tu->qchange_sleep);
1284 }
1285 
1286 static int snd_timer_user_open(struct inode *inode, struct file *file)
1287 {
1288 	struct snd_timer_user *tu;
1289 	int err;
1290 
1291 	err = nonseekable_open(inode, file);
1292 	if (err < 0)
1293 		return err;
1294 
1295 	tu = kzalloc(sizeof(*tu), GFP_KERNEL);
1296 	if (tu == NULL)
1297 		return -ENOMEM;
1298 	spin_lock_init(&tu->qlock);
1299 	init_waitqueue_head(&tu->qchange_sleep);
1300 	mutex_init(&tu->ioctl_lock);
1301 	tu->ticks = 1;
1302 	tu->queue_size = 128;
1303 	tu->queue = kmalloc(tu->queue_size * sizeof(struct snd_timer_read),
1304 			    GFP_KERNEL);
1305 	if (tu->queue == NULL) {
1306 		kfree(tu);
1307 		return -ENOMEM;
1308 	}
1309 	file->private_data = tu;
1310 	return 0;
1311 }
1312 
1313 static int snd_timer_user_release(struct inode *inode, struct file *file)
1314 {
1315 	struct snd_timer_user *tu;
1316 
1317 	if (file->private_data) {
1318 		tu = file->private_data;
1319 		file->private_data = NULL;
1320 		mutex_lock(&tu->ioctl_lock);
1321 		if (tu->timeri)
1322 			snd_timer_close(tu->timeri);
1323 		mutex_unlock(&tu->ioctl_lock);
1324 		kfree(tu->queue);
1325 		kfree(tu->tqueue);
1326 		kfree(tu);
1327 	}
1328 	return 0;
1329 }
1330 
1331 static void snd_timer_user_zero_id(struct snd_timer_id *id)
1332 {
1333 	id->dev_class = SNDRV_TIMER_CLASS_NONE;
1334 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1335 	id->card = -1;
1336 	id->device = -1;
1337 	id->subdevice = -1;
1338 }
1339 
1340 static void snd_timer_user_copy_id(struct snd_timer_id *id, struct snd_timer *timer)
1341 {
1342 	id->dev_class = timer->tmr_class;
1343 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1344 	id->card = timer->card ? timer->card->number : -1;
1345 	id->device = timer->tmr_device;
1346 	id->subdevice = timer->tmr_subdevice;
1347 }
1348 
1349 static int snd_timer_user_next_device(struct snd_timer_id __user *_tid)
1350 {
1351 	struct snd_timer_id id;
1352 	struct snd_timer *timer;
1353 	struct list_head *p;
1354 
1355 	if (copy_from_user(&id, _tid, sizeof(id)))
1356 		return -EFAULT;
1357 	mutex_lock(&register_mutex);
1358 	if (id.dev_class < 0) {		/* first item */
1359 		if (list_empty(&snd_timer_list))
1360 			snd_timer_user_zero_id(&id);
1361 		else {
1362 			timer = list_entry(snd_timer_list.next,
1363 					   struct snd_timer, device_list);
1364 			snd_timer_user_copy_id(&id, timer);
1365 		}
1366 	} else {
1367 		switch (id.dev_class) {
1368 		case SNDRV_TIMER_CLASS_GLOBAL:
1369 			id.device = id.device < 0 ? 0 : id.device + 1;
1370 			list_for_each(p, &snd_timer_list) {
1371 				timer = list_entry(p, struct snd_timer, device_list);
1372 				if (timer->tmr_class > SNDRV_TIMER_CLASS_GLOBAL) {
1373 					snd_timer_user_copy_id(&id, timer);
1374 					break;
1375 				}
1376 				if (timer->tmr_device >= id.device) {
1377 					snd_timer_user_copy_id(&id, timer);
1378 					break;
1379 				}
1380 			}
1381 			if (p == &snd_timer_list)
1382 				snd_timer_user_zero_id(&id);
1383 			break;
1384 		case SNDRV_TIMER_CLASS_CARD:
1385 		case SNDRV_TIMER_CLASS_PCM:
1386 			if (id.card < 0) {
1387 				id.card = 0;
1388 			} else {
1389 				if (id.card < 0) {
1390 					id.card = 0;
1391 				} else {
1392 					if (id.device < 0) {
1393 						id.device = 0;
1394 					} else {
1395 						if (id.subdevice < 0) {
1396 							id.subdevice = 0;
1397 						} else {
1398 							id.subdevice++;
1399 						}
1400 					}
1401 				}
1402 			}
1403 			list_for_each(p, &snd_timer_list) {
1404 				timer = list_entry(p, struct snd_timer, device_list);
1405 				if (timer->tmr_class > id.dev_class) {
1406 					snd_timer_user_copy_id(&id, timer);
1407 					break;
1408 				}
1409 				if (timer->tmr_class < id.dev_class)
1410 					continue;
1411 				if (timer->card->number > id.card) {
1412 					snd_timer_user_copy_id(&id, timer);
1413 					break;
1414 				}
1415 				if (timer->card->number < id.card)
1416 					continue;
1417 				if (timer->tmr_device > id.device) {
1418 					snd_timer_user_copy_id(&id, timer);
1419 					break;
1420 				}
1421 				if (timer->tmr_device < id.device)
1422 					continue;
1423 				if (timer->tmr_subdevice > id.subdevice) {
1424 					snd_timer_user_copy_id(&id, timer);
1425 					break;
1426 				}
1427 				if (timer->tmr_subdevice < id.subdevice)
1428 					continue;
1429 				snd_timer_user_copy_id(&id, timer);
1430 				break;
1431 			}
1432 			if (p == &snd_timer_list)
1433 				snd_timer_user_zero_id(&id);
1434 			break;
1435 		default:
1436 			snd_timer_user_zero_id(&id);
1437 		}
1438 	}
1439 	mutex_unlock(&register_mutex);
1440 	if (copy_to_user(_tid, &id, sizeof(*_tid)))
1441 		return -EFAULT;
1442 	return 0;
1443 }
1444 
1445 static int snd_timer_user_ginfo(struct file *file,
1446 				struct snd_timer_ginfo __user *_ginfo)
1447 {
1448 	struct snd_timer_ginfo *ginfo;
1449 	struct snd_timer_id tid;
1450 	struct snd_timer *t;
1451 	struct list_head *p;
1452 	int err = 0;
1453 
1454 	ginfo = memdup_user(_ginfo, sizeof(*ginfo));
1455 	if (IS_ERR(ginfo))
1456 		return PTR_ERR(ginfo);
1457 
1458 	tid = ginfo->tid;
1459 	memset(ginfo, 0, sizeof(*ginfo));
1460 	ginfo->tid = tid;
1461 	mutex_lock(&register_mutex);
1462 	t = snd_timer_find(&tid);
1463 	if (t != NULL) {
1464 		ginfo->card = t->card ? t->card->number : -1;
1465 		if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1466 			ginfo->flags |= SNDRV_TIMER_FLG_SLAVE;
1467 		strlcpy(ginfo->id, t->id, sizeof(ginfo->id));
1468 		strlcpy(ginfo->name, t->name, sizeof(ginfo->name));
1469 		ginfo->resolution = t->hw.resolution;
1470 		if (t->hw.resolution_min > 0) {
1471 			ginfo->resolution_min = t->hw.resolution_min;
1472 			ginfo->resolution_max = t->hw.resolution_max;
1473 		}
1474 		list_for_each(p, &t->open_list_head) {
1475 			ginfo->clients++;
1476 		}
1477 	} else {
1478 		err = -ENODEV;
1479 	}
1480 	mutex_unlock(&register_mutex);
1481 	if (err >= 0 && copy_to_user(_ginfo, ginfo, sizeof(*ginfo)))
1482 		err = -EFAULT;
1483 	kfree(ginfo);
1484 	return err;
1485 }
1486 
1487 static int snd_timer_user_gparams(struct file *file,
1488 				  struct snd_timer_gparams __user *_gparams)
1489 {
1490 	struct snd_timer_gparams gparams;
1491 	struct snd_timer *t;
1492 	int err;
1493 
1494 	if (copy_from_user(&gparams, _gparams, sizeof(gparams)))
1495 		return -EFAULT;
1496 	mutex_lock(&register_mutex);
1497 	t = snd_timer_find(&gparams.tid);
1498 	if (!t) {
1499 		err = -ENODEV;
1500 		goto _error;
1501 	}
1502 	if (!list_empty(&t->open_list_head)) {
1503 		err = -EBUSY;
1504 		goto _error;
1505 	}
1506 	if (!t->hw.set_period) {
1507 		err = -ENOSYS;
1508 		goto _error;
1509 	}
1510 	err = t->hw.set_period(t, gparams.period_num, gparams.period_den);
1511 _error:
1512 	mutex_unlock(&register_mutex);
1513 	return err;
1514 }
1515 
1516 static int snd_timer_user_gstatus(struct file *file,
1517 				  struct snd_timer_gstatus __user *_gstatus)
1518 {
1519 	struct snd_timer_gstatus gstatus;
1520 	struct snd_timer_id tid;
1521 	struct snd_timer *t;
1522 	int err = 0;
1523 
1524 	if (copy_from_user(&gstatus, _gstatus, sizeof(gstatus)))
1525 		return -EFAULT;
1526 	tid = gstatus.tid;
1527 	memset(&gstatus, 0, sizeof(gstatus));
1528 	gstatus.tid = tid;
1529 	mutex_lock(&register_mutex);
1530 	t = snd_timer_find(&tid);
1531 	if (t != NULL) {
1532 		if (t->hw.c_resolution)
1533 			gstatus.resolution = t->hw.c_resolution(t);
1534 		else
1535 			gstatus.resolution = t->hw.resolution;
1536 		if (t->hw.precise_resolution) {
1537 			t->hw.precise_resolution(t, &gstatus.resolution_num,
1538 						 &gstatus.resolution_den);
1539 		} else {
1540 			gstatus.resolution_num = gstatus.resolution;
1541 			gstatus.resolution_den = 1000000000uL;
1542 		}
1543 	} else {
1544 		err = -ENODEV;
1545 	}
1546 	mutex_unlock(&register_mutex);
1547 	if (err >= 0 && copy_to_user(_gstatus, &gstatus, sizeof(gstatus)))
1548 		err = -EFAULT;
1549 	return err;
1550 }
1551 
1552 static int snd_timer_user_tselect(struct file *file,
1553 				  struct snd_timer_select __user *_tselect)
1554 {
1555 	struct snd_timer_user *tu;
1556 	struct snd_timer_select tselect;
1557 	char str[32];
1558 	int err = 0;
1559 
1560 	tu = file->private_data;
1561 	if (tu->timeri) {
1562 		snd_timer_close(tu->timeri);
1563 		tu->timeri = NULL;
1564 	}
1565 	if (copy_from_user(&tselect, _tselect, sizeof(tselect))) {
1566 		err = -EFAULT;
1567 		goto __err;
1568 	}
1569 	sprintf(str, "application %i", current->pid);
1570 	if (tselect.id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
1571 		tselect.id.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION;
1572 	err = snd_timer_open(&tu->timeri, str, &tselect.id, current->pid);
1573 	if (err < 0)
1574 		goto __err;
1575 
1576 	kfree(tu->queue);
1577 	tu->queue = NULL;
1578 	kfree(tu->tqueue);
1579 	tu->tqueue = NULL;
1580 	if (tu->tread) {
1581 		tu->tqueue = kmalloc(tu->queue_size * sizeof(struct snd_timer_tread),
1582 				     GFP_KERNEL);
1583 		if (tu->tqueue == NULL)
1584 			err = -ENOMEM;
1585 	} else {
1586 		tu->queue = kmalloc(tu->queue_size * sizeof(struct snd_timer_read),
1587 				    GFP_KERNEL);
1588 		if (tu->queue == NULL)
1589 			err = -ENOMEM;
1590 	}
1591 
1592       	if (err < 0) {
1593 		snd_timer_close(tu->timeri);
1594       		tu->timeri = NULL;
1595       	} else {
1596 		tu->timeri->flags |= SNDRV_TIMER_IFLG_FAST;
1597 		tu->timeri->callback = tu->tread
1598 			? snd_timer_user_tinterrupt : snd_timer_user_interrupt;
1599 		tu->timeri->ccallback = snd_timer_user_ccallback;
1600 		tu->timeri->callback_data = (void *)tu;
1601 		tu->timeri->disconnect = snd_timer_user_disconnect;
1602 	}
1603 
1604       __err:
1605 	return err;
1606 }
1607 
1608 static int snd_timer_user_info(struct file *file,
1609 			       struct snd_timer_info __user *_info)
1610 {
1611 	struct snd_timer_user *tu;
1612 	struct snd_timer_info *info;
1613 	struct snd_timer *t;
1614 	int err = 0;
1615 
1616 	tu = file->private_data;
1617 	if (!tu->timeri)
1618 		return -EBADFD;
1619 	t = tu->timeri->timer;
1620 	if (!t)
1621 		return -EBADFD;
1622 
1623 	info = kzalloc(sizeof(*info), GFP_KERNEL);
1624 	if (! info)
1625 		return -ENOMEM;
1626 	info->card = t->card ? t->card->number : -1;
1627 	if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1628 		info->flags |= SNDRV_TIMER_FLG_SLAVE;
1629 	strlcpy(info->id, t->id, sizeof(info->id));
1630 	strlcpy(info->name, t->name, sizeof(info->name));
1631 	info->resolution = t->hw.resolution;
1632 	if (copy_to_user(_info, info, sizeof(*_info)))
1633 		err = -EFAULT;
1634 	kfree(info);
1635 	return err;
1636 }
1637 
1638 static int snd_timer_user_params(struct file *file,
1639 				 struct snd_timer_params __user *_params)
1640 {
1641 	struct snd_timer_user *tu;
1642 	struct snd_timer_params params;
1643 	struct snd_timer *t;
1644 	struct snd_timer_read *tr;
1645 	struct snd_timer_tread *ttr;
1646 	int err;
1647 
1648 	tu = file->private_data;
1649 	if (!tu->timeri)
1650 		return -EBADFD;
1651 	t = tu->timeri->timer;
1652 	if (!t)
1653 		return -EBADFD;
1654 	if (copy_from_user(&params, _params, sizeof(params)))
1655 		return -EFAULT;
1656 	if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE) && params.ticks < 1) {
1657 		err = -EINVAL;
1658 		goto _end;
1659 	}
1660 	if (params.queue_size > 0 &&
1661 	    (params.queue_size < 32 || params.queue_size > 1024)) {
1662 		err = -EINVAL;
1663 		goto _end;
1664 	}
1665 	if (params.filter & ~((1<<SNDRV_TIMER_EVENT_RESOLUTION)|
1666 			      (1<<SNDRV_TIMER_EVENT_TICK)|
1667 			      (1<<SNDRV_TIMER_EVENT_START)|
1668 			      (1<<SNDRV_TIMER_EVENT_STOP)|
1669 			      (1<<SNDRV_TIMER_EVENT_CONTINUE)|
1670 			      (1<<SNDRV_TIMER_EVENT_PAUSE)|
1671 			      (1<<SNDRV_TIMER_EVENT_SUSPEND)|
1672 			      (1<<SNDRV_TIMER_EVENT_RESUME)|
1673 			      (1<<SNDRV_TIMER_EVENT_MSTART)|
1674 			      (1<<SNDRV_TIMER_EVENT_MSTOP)|
1675 			      (1<<SNDRV_TIMER_EVENT_MCONTINUE)|
1676 			      (1<<SNDRV_TIMER_EVENT_MPAUSE)|
1677 			      (1<<SNDRV_TIMER_EVENT_MSUSPEND)|
1678 			      (1<<SNDRV_TIMER_EVENT_MRESUME))) {
1679 		err = -EINVAL;
1680 		goto _end;
1681 	}
1682 	snd_timer_stop(tu->timeri);
1683 	spin_lock_irq(&t->lock);
1684 	tu->timeri->flags &= ~(SNDRV_TIMER_IFLG_AUTO|
1685 			       SNDRV_TIMER_IFLG_EXCLUSIVE|
1686 			       SNDRV_TIMER_IFLG_EARLY_EVENT);
1687 	if (params.flags & SNDRV_TIMER_PSFLG_AUTO)
1688 		tu->timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1689 	if (params.flags & SNDRV_TIMER_PSFLG_EXCLUSIVE)
1690 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EXCLUSIVE;
1691 	if (params.flags & SNDRV_TIMER_PSFLG_EARLY_EVENT)
1692 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EARLY_EVENT;
1693 	spin_unlock_irq(&t->lock);
1694 	if (params.queue_size > 0 &&
1695 	    (unsigned int)tu->queue_size != params.queue_size) {
1696 		if (tu->tread) {
1697 			ttr = kmalloc(params.queue_size * sizeof(*ttr),
1698 				      GFP_KERNEL);
1699 			if (ttr) {
1700 				kfree(tu->tqueue);
1701 				tu->queue_size = params.queue_size;
1702 				tu->tqueue = ttr;
1703 			}
1704 		} else {
1705 			tr = kmalloc(params.queue_size * sizeof(*tr),
1706 				     GFP_KERNEL);
1707 			if (tr) {
1708 				kfree(tu->queue);
1709 				tu->queue_size = params.queue_size;
1710 				tu->queue = tr;
1711 			}
1712 		}
1713 	}
1714 	tu->qhead = tu->qtail = tu->qused = 0;
1715 	if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
1716 		if (tu->tread) {
1717 			struct snd_timer_tread tread;
1718 			tread.event = SNDRV_TIMER_EVENT_EARLY;
1719 			tread.tstamp.tv_sec = 0;
1720 			tread.tstamp.tv_nsec = 0;
1721 			tread.val = 0;
1722 			snd_timer_user_append_to_tqueue(tu, &tread);
1723 		} else {
1724 			struct snd_timer_read *r = &tu->queue[0];
1725 			r->resolution = 0;
1726 			r->ticks = 0;
1727 			tu->qused++;
1728 			tu->qtail++;
1729 		}
1730 	}
1731 	tu->filter = params.filter;
1732 	tu->ticks = params.ticks;
1733 	err = 0;
1734  _end:
1735 	if (copy_to_user(_params, &params, sizeof(params)))
1736 		return -EFAULT;
1737 	return err;
1738 }
1739 
1740 static int snd_timer_user_status(struct file *file,
1741 				 struct snd_timer_status __user *_status)
1742 {
1743 	struct snd_timer_user *tu;
1744 	struct snd_timer_status status;
1745 
1746 	tu = file->private_data;
1747 	if (!tu->timeri)
1748 		return -EBADFD;
1749 	memset(&status, 0, sizeof(status));
1750 	status.tstamp = tu->tstamp;
1751 	status.resolution = snd_timer_resolution(tu->timeri);
1752 	status.lost = tu->timeri->lost;
1753 	status.overrun = tu->overrun;
1754 	spin_lock_irq(&tu->qlock);
1755 	status.queue = tu->qused;
1756 	spin_unlock_irq(&tu->qlock);
1757 	if (copy_to_user(_status, &status, sizeof(status)))
1758 		return -EFAULT;
1759 	return 0;
1760 }
1761 
1762 static int snd_timer_user_start(struct file *file)
1763 {
1764 	int err;
1765 	struct snd_timer_user *tu;
1766 
1767 	tu = file->private_data;
1768 	if (!tu->timeri)
1769 		return -EBADFD;
1770 	snd_timer_stop(tu->timeri);
1771 	tu->timeri->lost = 0;
1772 	tu->last_resolution = 0;
1773 	return (err = snd_timer_start(tu->timeri, tu->ticks)) < 0 ? err : 0;
1774 }
1775 
1776 static int snd_timer_user_stop(struct file *file)
1777 {
1778 	int err;
1779 	struct snd_timer_user *tu;
1780 
1781 	tu = file->private_data;
1782 	if (!tu->timeri)
1783 		return -EBADFD;
1784 	return (err = snd_timer_stop(tu->timeri)) < 0 ? err : 0;
1785 }
1786 
1787 static int snd_timer_user_continue(struct file *file)
1788 {
1789 	int err;
1790 	struct snd_timer_user *tu;
1791 
1792 	tu = file->private_data;
1793 	if (!tu->timeri)
1794 		return -EBADFD;
1795 	tu->timeri->lost = 0;
1796 	return (err = snd_timer_continue(tu->timeri)) < 0 ? err : 0;
1797 }
1798 
1799 static int snd_timer_user_pause(struct file *file)
1800 {
1801 	int err;
1802 	struct snd_timer_user *tu;
1803 
1804 	tu = file->private_data;
1805 	if (!tu->timeri)
1806 		return -EBADFD;
1807 	return (err = snd_timer_pause(tu->timeri)) < 0 ? err : 0;
1808 }
1809 
1810 enum {
1811 	SNDRV_TIMER_IOCTL_START_OLD = _IO('T', 0x20),
1812 	SNDRV_TIMER_IOCTL_STOP_OLD = _IO('T', 0x21),
1813 	SNDRV_TIMER_IOCTL_CONTINUE_OLD = _IO('T', 0x22),
1814 	SNDRV_TIMER_IOCTL_PAUSE_OLD = _IO('T', 0x23),
1815 };
1816 
1817 static long __snd_timer_user_ioctl(struct file *file, unsigned int cmd,
1818 				 unsigned long arg)
1819 {
1820 	struct snd_timer_user *tu;
1821 	void __user *argp = (void __user *)arg;
1822 	int __user *p = argp;
1823 
1824 	tu = file->private_data;
1825 	switch (cmd) {
1826 	case SNDRV_TIMER_IOCTL_PVERSION:
1827 		return put_user(SNDRV_TIMER_VERSION, p) ? -EFAULT : 0;
1828 	case SNDRV_TIMER_IOCTL_NEXT_DEVICE:
1829 		return snd_timer_user_next_device(argp);
1830 	case SNDRV_TIMER_IOCTL_TREAD:
1831 	{
1832 		int xarg;
1833 
1834 		if (tu->timeri)	/* too late */
1835 			return -EBUSY;
1836 		if (get_user(xarg, p))
1837 			return -EFAULT;
1838 		tu->tread = xarg ? 1 : 0;
1839 		return 0;
1840 	}
1841 	case SNDRV_TIMER_IOCTL_GINFO:
1842 		return snd_timer_user_ginfo(file, argp);
1843 	case SNDRV_TIMER_IOCTL_GPARAMS:
1844 		return snd_timer_user_gparams(file, argp);
1845 	case SNDRV_TIMER_IOCTL_GSTATUS:
1846 		return snd_timer_user_gstatus(file, argp);
1847 	case SNDRV_TIMER_IOCTL_SELECT:
1848 		return snd_timer_user_tselect(file, argp);
1849 	case SNDRV_TIMER_IOCTL_INFO:
1850 		return snd_timer_user_info(file, argp);
1851 	case SNDRV_TIMER_IOCTL_PARAMS:
1852 		return snd_timer_user_params(file, argp);
1853 	case SNDRV_TIMER_IOCTL_STATUS:
1854 		return snd_timer_user_status(file, argp);
1855 	case SNDRV_TIMER_IOCTL_START:
1856 	case SNDRV_TIMER_IOCTL_START_OLD:
1857 		return snd_timer_user_start(file);
1858 	case SNDRV_TIMER_IOCTL_STOP:
1859 	case SNDRV_TIMER_IOCTL_STOP_OLD:
1860 		return snd_timer_user_stop(file);
1861 	case SNDRV_TIMER_IOCTL_CONTINUE:
1862 	case SNDRV_TIMER_IOCTL_CONTINUE_OLD:
1863 		return snd_timer_user_continue(file);
1864 	case SNDRV_TIMER_IOCTL_PAUSE:
1865 	case SNDRV_TIMER_IOCTL_PAUSE_OLD:
1866 		return snd_timer_user_pause(file);
1867 	}
1868 	return -ENOTTY;
1869 }
1870 
1871 static long snd_timer_user_ioctl(struct file *file, unsigned int cmd,
1872 				 unsigned long arg)
1873 {
1874 	struct snd_timer_user *tu = file->private_data;
1875 	long ret;
1876 
1877 	mutex_lock(&tu->ioctl_lock);
1878 	ret = __snd_timer_user_ioctl(file, cmd, arg);
1879 	mutex_unlock(&tu->ioctl_lock);
1880 	return ret;
1881 }
1882 
1883 static int snd_timer_user_fasync(int fd, struct file * file, int on)
1884 {
1885 	struct snd_timer_user *tu;
1886 
1887 	tu = file->private_data;
1888 	return fasync_helper(fd, file, on, &tu->fasync);
1889 }
1890 
1891 static ssize_t snd_timer_user_read(struct file *file, char __user *buffer,
1892 				   size_t count, loff_t *offset)
1893 {
1894 	struct snd_timer_user *tu;
1895 	long result = 0, unit;
1896 	int err = 0;
1897 
1898 	tu = file->private_data;
1899 	unit = tu->tread ? sizeof(struct snd_timer_tread) : sizeof(struct snd_timer_read);
1900 	spin_lock_irq(&tu->qlock);
1901 	while ((long)count - result >= unit) {
1902 		while (!tu->qused) {
1903 			wait_queue_t wait;
1904 
1905 			if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
1906 				err = -EAGAIN;
1907 				break;
1908 			}
1909 
1910 			set_current_state(TASK_INTERRUPTIBLE);
1911 			init_waitqueue_entry(&wait, current);
1912 			add_wait_queue(&tu->qchange_sleep, &wait);
1913 
1914 			spin_unlock_irq(&tu->qlock);
1915 			schedule();
1916 			spin_lock_irq(&tu->qlock);
1917 
1918 			remove_wait_queue(&tu->qchange_sleep, &wait);
1919 
1920 			if (tu->disconnected) {
1921 				err = -ENODEV;
1922 				break;
1923 			}
1924 			if (signal_pending(current)) {
1925 				err = -ERESTARTSYS;
1926 				break;
1927 			}
1928 		}
1929 
1930 		spin_unlock_irq(&tu->qlock);
1931 		if (err < 0)
1932 			goto _error;
1933 
1934 		if (tu->tread) {
1935 			if (copy_to_user(buffer, &tu->tqueue[tu->qhead++],
1936 					 sizeof(struct snd_timer_tread))) {
1937 				err = -EFAULT;
1938 				goto _error;
1939 			}
1940 		} else {
1941 			if (copy_to_user(buffer, &tu->queue[tu->qhead++],
1942 					 sizeof(struct snd_timer_read))) {
1943 				err = -EFAULT;
1944 				goto _error;
1945 			}
1946 		}
1947 
1948 		tu->qhead %= tu->queue_size;
1949 
1950 		result += unit;
1951 		buffer += unit;
1952 
1953 		spin_lock_irq(&tu->qlock);
1954 		tu->qused--;
1955 	}
1956 	spin_unlock_irq(&tu->qlock);
1957  _error:
1958 	return result > 0 ? result : err;
1959 }
1960 
1961 static unsigned int snd_timer_user_poll(struct file *file, poll_table * wait)
1962 {
1963         unsigned int mask;
1964         struct snd_timer_user *tu;
1965 
1966         tu = file->private_data;
1967 
1968         poll_wait(file, &tu->qchange_sleep, wait);
1969 
1970 	mask = 0;
1971 	if (tu->qused)
1972 		mask |= POLLIN | POLLRDNORM;
1973 	if (tu->disconnected)
1974 		mask |= POLLERR;
1975 
1976 	return mask;
1977 }
1978 
1979 #ifdef CONFIG_COMPAT
1980 #include "timer_compat.c"
1981 #else
1982 #define snd_timer_user_ioctl_compat	NULL
1983 #endif
1984 
1985 static const struct file_operations snd_timer_f_ops =
1986 {
1987 	.owner =	THIS_MODULE,
1988 	.read =		snd_timer_user_read,
1989 	.open =		snd_timer_user_open,
1990 	.release =	snd_timer_user_release,
1991 	.llseek =	no_llseek,
1992 	.poll =		snd_timer_user_poll,
1993 	.unlocked_ioctl =	snd_timer_user_ioctl,
1994 	.compat_ioctl =	snd_timer_user_ioctl_compat,
1995 	.fasync = 	snd_timer_user_fasync,
1996 };
1997 
1998 /* unregister the system timer */
1999 static void snd_timer_free_all(void)
2000 {
2001 	struct snd_timer *timer, *n;
2002 
2003 	list_for_each_entry_safe(timer, n, &snd_timer_list, device_list)
2004 		snd_timer_free(timer);
2005 }
2006 
2007 static struct device timer_dev;
2008 
2009 /*
2010  *  ENTRY functions
2011  */
2012 
2013 static int __init alsa_timer_init(void)
2014 {
2015 	int err;
2016 
2017 	snd_device_initialize(&timer_dev, NULL);
2018 	dev_set_name(&timer_dev, "timer");
2019 
2020 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
2021 	snd_oss_info_register(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1,
2022 			      "system timer");
2023 #endif
2024 
2025 	err = snd_timer_register_system();
2026 	if (err < 0) {
2027 		pr_err("ALSA: unable to register system timer (%i)\n", err);
2028 		put_device(&timer_dev);
2029 		return err;
2030 	}
2031 
2032 	err = snd_register_device(SNDRV_DEVICE_TYPE_TIMER, NULL, 0,
2033 				  &snd_timer_f_ops, NULL, &timer_dev);
2034 	if (err < 0) {
2035 		pr_err("ALSA: unable to register timer device (%i)\n", err);
2036 		snd_timer_free_all();
2037 		put_device(&timer_dev);
2038 		return err;
2039 	}
2040 
2041 	snd_timer_proc_init();
2042 	return 0;
2043 }
2044 
2045 static void __exit alsa_timer_exit(void)
2046 {
2047 	snd_unregister_device(&timer_dev);
2048 	snd_timer_free_all();
2049 	put_device(&timer_dev);
2050 	snd_timer_proc_done();
2051 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
2052 	snd_oss_info_unregister(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1);
2053 #endif
2054 }
2055 
2056 module_init(alsa_timer_init)
2057 module_exit(alsa_timer_exit)
2058 
2059 EXPORT_SYMBOL(snd_timer_open);
2060 EXPORT_SYMBOL(snd_timer_close);
2061 EXPORT_SYMBOL(snd_timer_resolution);
2062 EXPORT_SYMBOL(snd_timer_start);
2063 EXPORT_SYMBOL(snd_timer_stop);
2064 EXPORT_SYMBOL(snd_timer_continue);
2065 EXPORT_SYMBOL(snd_timer_pause);
2066 EXPORT_SYMBOL(snd_timer_new);
2067 EXPORT_SYMBOL(snd_timer_notify);
2068 EXPORT_SYMBOL(snd_timer_global_new);
2069 EXPORT_SYMBOL(snd_timer_global_free);
2070 EXPORT_SYMBOL(snd_timer_global_register);
2071 EXPORT_SYMBOL(snd_timer_interrupt);
2072