xref: /linux/sound/core/timer.c (revision 33dea5aae0320345af26ae9aba0894a930e0d4ec)
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 <linux/sched/signal.h>
31 #include <sound/core.h>
32 #include <sound/timer.h>
33 #include <sound/control.h>
34 #include <sound/info.h>
35 #include <sound/minors.h>
36 #include <sound/initval.h>
37 #include <linux/kmod.h>
38 
39 /* internal flags */
40 #define SNDRV_TIMER_IFLG_PAUSED		0x00010000
41 
42 #if IS_ENABLED(CONFIG_SND_HRTIMER)
43 #define DEFAULT_TIMER_LIMIT 4
44 #else
45 #define DEFAULT_TIMER_LIMIT 1
46 #endif
47 
48 static int timer_limit = DEFAULT_TIMER_LIMIT;
49 static int timer_tstamp_monotonic = 1;
50 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.de>");
51 MODULE_DESCRIPTION("ALSA timer interface");
52 MODULE_LICENSE("GPL");
53 module_param(timer_limit, int, 0444);
54 MODULE_PARM_DESC(timer_limit, "Maximum global timers in system.");
55 module_param(timer_tstamp_monotonic, int, 0444);
56 MODULE_PARM_DESC(timer_tstamp_monotonic, "Use posix monotonic clock source for timestamps (default).");
57 
58 MODULE_ALIAS_CHARDEV(CONFIG_SND_MAJOR, SNDRV_MINOR_TIMER);
59 MODULE_ALIAS("devname:snd/timer");
60 
61 struct snd_timer_user {
62 	struct snd_timer_instance *timeri;
63 	int tread;		/* enhanced read with timestamps and events */
64 	unsigned long ticks;
65 	unsigned long overrun;
66 	int qhead;
67 	int qtail;
68 	int qused;
69 	int queue_size;
70 	bool disconnected;
71 	struct snd_timer_read *queue;
72 	struct snd_timer_tread *tqueue;
73 	spinlock_t qlock;
74 	unsigned long last_resolution;
75 	unsigned int filter;
76 	struct timespec tstamp;		/* trigger tstamp */
77 	wait_queue_head_t qchange_sleep;
78 	struct fasync_struct *fasync;
79 	struct mutex ioctl_lock;
80 };
81 
82 /* list of timers */
83 static LIST_HEAD(snd_timer_list);
84 
85 /* list of slave instances */
86 static LIST_HEAD(snd_timer_slave_list);
87 
88 /* lock for slave active lists */
89 static DEFINE_SPINLOCK(slave_active_lock);
90 
91 static DEFINE_MUTEX(register_mutex);
92 
93 static int snd_timer_free(struct snd_timer *timer);
94 static int snd_timer_dev_free(struct snd_device *device);
95 static int snd_timer_dev_register(struct snd_device *device);
96 static int snd_timer_dev_disconnect(struct snd_device *device);
97 
98 static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left);
99 
100 /*
101  * create a timer instance with the given owner string.
102  * when timer is not NULL, increments the module counter
103  */
104 static struct snd_timer_instance *snd_timer_instance_new(char *owner,
105 							 struct snd_timer *timer)
106 {
107 	struct snd_timer_instance *timeri;
108 	timeri = kzalloc(sizeof(*timeri), GFP_KERNEL);
109 	if (timeri == NULL)
110 		return NULL;
111 	timeri->owner = kstrdup(owner, GFP_KERNEL);
112 	if (! timeri->owner) {
113 		kfree(timeri);
114 		return NULL;
115 	}
116 	INIT_LIST_HEAD(&timeri->open_list);
117 	INIT_LIST_HEAD(&timeri->active_list);
118 	INIT_LIST_HEAD(&timeri->ack_list);
119 	INIT_LIST_HEAD(&timeri->slave_list_head);
120 	INIT_LIST_HEAD(&timeri->slave_active_head);
121 
122 	timeri->timer = timer;
123 	if (timer && !try_module_get(timer->module)) {
124 		kfree(timeri->owner);
125 		kfree(timeri);
126 		return NULL;
127 	}
128 
129 	return timeri;
130 }
131 
132 /*
133  * find a timer instance from the given timer id
134  */
135 static struct snd_timer *snd_timer_find(struct snd_timer_id *tid)
136 {
137 	struct snd_timer *timer = NULL;
138 
139 	list_for_each_entry(timer, &snd_timer_list, device_list) {
140 		if (timer->tmr_class != tid->dev_class)
141 			continue;
142 		if ((timer->tmr_class == SNDRV_TIMER_CLASS_CARD ||
143 		     timer->tmr_class == SNDRV_TIMER_CLASS_PCM) &&
144 		    (timer->card == NULL ||
145 		     timer->card->number != tid->card))
146 			continue;
147 		if (timer->tmr_device != tid->device)
148 			continue;
149 		if (timer->tmr_subdevice != tid->subdevice)
150 			continue;
151 		return timer;
152 	}
153 	return NULL;
154 }
155 
156 #ifdef CONFIG_MODULES
157 
158 static void snd_timer_request(struct snd_timer_id *tid)
159 {
160 	switch (tid->dev_class) {
161 	case SNDRV_TIMER_CLASS_GLOBAL:
162 		if (tid->device < timer_limit)
163 			request_module("snd-timer-%i", tid->device);
164 		break;
165 	case SNDRV_TIMER_CLASS_CARD:
166 	case SNDRV_TIMER_CLASS_PCM:
167 		if (tid->card < snd_ecards_limit)
168 			request_module("snd-card-%i", tid->card);
169 		break;
170 	default:
171 		break;
172 	}
173 }
174 
175 #endif
176 
177 /*
178  * look for a master instance matching with the slave id of the given slave.
179  * when found, relink the open_link of the slave.
180  *
181  * call this with register_mutex down.
182  */
183 static int snd_timer_check_slave(struct snd_timer_instance *slave)
184 {
185 	struct snd_timer *timer;
186 	struct snd_timer_instance *master;
187 
188 	/* FIXME: it's really dumb to look up all entries.. */
189 	list_for_each_entry(timer, &snd_timer_list, device_list) {
190 		list_for_each_entry(master, &timer->open_list_head, open_list) {
191 			if (slave->slave_class == master->slave_class &&
192 			    slave->slave_id == master->slave_id) {
193 				if (master->timer->num_instances >=
194 				    master->timer->max_instances)
195 					return -EBUSY;
196 				list_move_tail(&slave->open_list,
197 					       &master->slave_list_head);
198 				master->timer->num_instances++;
199 				spin_lock_irq(&slave_active_lock);
200 				slave->master = master;
201 				slave->timer = master->timer;
202 				spin_unlock_irq(&slave_active_lock);
203 				return 0;
204 			}
205 		}
206 	}
207 	return 0;
208 }
209 
210 /*
211  * look for slave instances matching with the slave id of the given master.
212  * when found, relink the open_link of slaves.
213  *
214  * call this with register_mutex down.
215  */
216 static int snd_timer_check_master(struct snd_timer_instance *master)
217 {
218 	struct snd_timer_instance *slave, *tmp;
219 
220 	/* check all pending slaves */
221 	list_for_each_entry_safe(slave, tmp, &snd_timer_slave_list, open_list) {
222 		if (slave->slave_class == master->slave_class &&
223 		    slave->slave_id == master->slave_id) {
224 			if (master->timer->num_instances >=
225 			    master->timer->max_instances)
226 				return -EBUSY;
227 			list_move_tail(&slave->open_list, &master->slave_list_head);
228 			master->timer->num_instances++;
229 			spin_lock_irq(&slave_active_lock);
230 			spin_lock(&master->timer->lock);
231 			slave->master = master;
232 			slave->timer = master->timer;
233 			if (slave->flags & SNDRV_TIMER_IFLG_RUNNING)
234 				list_add_tail(&slave->active_list,
235 					      &master->slave_active_head);
236 			spin_unlock(&master->timer->lock);
237 			spin_unlock_irq(&slave_active_lock);
238 		}
239 	}
240 	return 0;
241 }
242 
243 static int snd_timer_close_locked(struct snd_timer_instance *timeri);
244 
245 /*
246  * open a timer instance
247  * when opening a master, the slave id must be here given.
248  */
249 int snd_timer_open(struct snd_timer_instance **ti,
250 		   char *owner, struct snd_timer_id *tid,
251 		   unsigned int slave_id)
252 {
253 	struct snd_timer *timer;
254 	struct snd_timer_instance *timeri = NULL;
255 	int err;
256 
257 	if (tid->dev_class == SNDRV_TIMER_CLASS_SLAVE) {
258 		/* open a slave instance */
259 		if (tid->dev_sclass <= SNDRV_TIMER_SCLASS_NONE ||
260 		    tid->dev_sclass > SNDRV_TIMER_SCLASS_OSS_SEQUENCER) {
261 			pr_debug("ALSA: timer: invalid slave class %i\n",
262 				 tid->dev_sclass);
263 			return -EINVAL;
264 		}
265 		mutex_lock(&register_mutex);
266 		timeri = snd_timer_instance_new(owner, NULL);
267 		if (!timeri) {
268 			mutex_unlock(&register_mutex);
269 			return -ENOMEM;
270 		}
271 		timeri->slave_class = tid->dev_sclass;
272 		timeri->slave_id = tid->device;
273 		timeri->flags |= SNDRV_TIMER_IFLG_SLAVE;
274 		list_add_tail(&timeri->open_list, &snd_timer_slave_list);
275 		err = snd_timer_check_slave(timeri);
276 		if (err < 0) {
277 			snd_timer_close_locked(timeri);
278 			timeri = NULL;
279 		}
280 		mutex_unlock(&register_mutex);
281 		*ti = timeri;
282 		return err;
283 	}
284 
285 	/* open a master instance */
286 	mutex_lock(&register_mutex);
287 	timer = snd_timer_find(tid);
288 #ifdef CONFIG_MODULES
289 	if (!timer) {
290 		mutex_unlock(&register_mutex);
291 		snd_timer_request(tid);
292 		mutex_lock(&register_mutex);
293 		timer = snd_timer_find(tid);
294 	}
295 #endif
296 	if (!timer) {
297 		mutex_unlock(&register_mutex);
298 		return -ENODEV;
299 	}
300 	if (!list_empty(&timer->open_list_head)) {
301 		timeri = list_entry(timer->open_list_head.next,
302 				    struct snd_timer_instance, open_list);
303 		if (timeri->flags & SNDRV_TIMER_IFLG_EXCLUSIVE) {
304 			mutex_unlock(&register_mutex);
305 			return -EBUSY;
306 		}
307 	}
308 	if (timer->num_instances >= timer->max_instances) {
309 		mutex_unlock(&register_mutex);
310 		return -EBUSY;
311 	}
312 	timeri = snd_timer_instance_new(owner, timer);
313 	if (!timeri) {
314 		mutex_unlock(&register_mutex);
315 		return -ENOMEM;
316 	}
317 	/* take a card refcount for safe disconnection */
318 	if (timer->card)
319 		get_device(&timer->card->card_dev);
320 	timeri->slave_class = tid->dev_sclass;
321 	timeri->slave_id = slave_id;
322 
323 	if (list_empty(&timer->open_list_head) && timer->hw.open) {
324 		int err = timer->hw.open(timer);
325 		if (err) {
326 			kfree(timeri->owner);
327 			kfree(timeri);
328 
329 			if (timer->card)
330 				put_device(&timer->card->card_dev);
331 			module_put(timer->module);
332 			mutex_unlock(&register_mutex);
333 			return err;
334 		}
335 	}
336 
337 	list_add_tail(&timeri->open_list, &timer->open_list_head);
338 	timer->num_instances++;
339 	err = snd_timer_check_master(timeri);
340 	if (err < 0) {
341 		snd_timer_close_locked(timeri);
342 		timeri = NULL;
343 	}
344 	mutex_unlock(&register_mutex);
345 	*ti = timeri;
346 	return err;
347 }
348 EXPORT_SYMBOL(snd_timer_open);
349 
350 /*
351  * close a timer instance
352  * call this with register_mutex down.
353  */
354 static int snd_timer_close_locked(struct snd_timer_instance *timeri)
355 {
356 	struct snd_timer *timer = NULL;
357 	struct snd_timer_instance *slave, *tmp;
358 
359 	list_del(&timeri->open_list);
360 
361 	/* force to stop the timer */
362 	snd_timer_stop(timeri);
363 
364 	timer = timeri->timer;
365 	if (timer) {
366 		timer->num_instances--;
367 		/* wait, until the active callback is finished */
368 		spin_lock_irq(&timer->lock);
369 		while (timeri->flags & SNDRV_TIMER_IFLG_CALLBACK) {
370 			spin_unlock_irq(&timer->lock);
371 			udelay(10);
372 			spin_lock_irq(&timer->lock);
373 		}
374 		spin_unlock_irq(&timer->lock);
375 
376 		/* remove slave links */
377 		spin_lock_irq(&slave_active_lock);
378 		spin_lock(&timer->lock);
379 		list_for_each_entry_safe(slave, tmp, &timeri->slave_list_head,
380 					 open_list) {
381 			list_move_tail(&slave->open_list, &snd_timer_slave_list);
382 			timer->num_instances--;
383 			slave->master = NULL;
384 			slave->timer = NULL;
385 			list_del_init(&slave->ack_list);
386 			list_del_init(&slave->active_list);
387 		}
388 		spin_unlock(&timer->lock);
389 		spin_unlock_irq(&slave_active_lock);
390 
391 		/* slave doesn't need to release timer resources below */
392 		if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
393 			timer = NULL;
394 	}
395 
396 	if (timeri->private_free)
397 		timeri->private_free(timeri);
398 	kfree(timeri->owner);
399 	kfree(timeri);
400 
401 	if (timer) {
402 		if (list_empty(&timer->open_list_head) && timer->hw.close)
403 			timer->hw.close(timer);
404 		/* release a card refcount for safe disconnection */
405 		if (timer->card)
406 			put_device(&timer->card->card_dev);
407 		module_put(timer->module);
408 	}
409 
410 	return 0;
411 }
412 
413 /*
414  * close a timer instance
415  */
416 int snd_timer_close(struct snd_timer_instance *timeri)
417 {
418 	int err;
419 
420 	if (snd_BUG_ON(!timeri))
421 		return -ENXIO;
422 
423 	mutex_lock(&register_mutex);
424 	err = snd_timer_close_locked(timeri);
425 	mutex_unlock(&register_mutex);
426 	return err;
427 }
428 EXPORT_SYMBOL(snd_timer_close);
429 
430 unsigned long snd_timer_resolution(struct snd_timer_instance *timeri)
431 {
432 	struct snd_timer * timer;
433 
434 	if (timeri == NULL)
435 		return 0;
436 	timer = timeri->timer;
437 	if (timer) {
438 		if (timer->hw.c_resolution)
439 			return timer->hw.c_resolution(timer);
440 		return timer->hw.resolution;
441 	}
442 	return 0;
443 }
444 EXPORT_SYMBOL(snd_timer_resolution);
445 
446 static void snd_timer_notify1(struct snd_timer_instance *ti, int event)
447 {
448 	struct snd_timer *timer;
449 	unsigned long resolution = 0;
450 	struct snd_timer_instance *ts;
451 	struct timespec tstamp;
452 
453 	if (timer_tstamp_monotonic)
454 		ktime_get_ts(&tstamp);
455 	else
456 		getnstimeofday(&tstamp);
457 	if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_START ||
458 		       event > SNDRV_TIMER_EVENT_PAUSE))
459 		return;
460 	if (event == SNDRV_TIMER_EVENT_START ||
461 	    event == SNDRV_TIMER_EVENT_CONTINUE)
462 		resolution = snd_timer_resolution(ti);
463 	if (ti->ccallback)
464 		ti->ccallback(ti, event, &tstamp, resolution);
465 	if (ti->flags & SNDRV_TIMER_IFLG_SLAVE)
466 		return;
467 	timer = ti->timer;
468 	if (timer == NULL)
469 		return;
470 	if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
471 		return;
472 	list_for_each_entry(ts, &ti->slave_active_head, active_list)
473 		if (ts->ccallback)
474 			ts->ccallback(ts, event + 100, &tstamp, resolution);
475 }
476 
477 /* start/continue a master timer */
478 static int snd_timer_start1(struct snd_timer_instance *timeri,
479 			    bool start, unsigned long ticks)
480 {
481 	struct snd_timer *timer;
482 	int result;
483 	unsigned long flags;
484 
485 	timer = timeri->timer;
486 	if (!timer)
487 		return -EINVAL;
488 
489 	spin_lock_irqsave(&timer->lock, flags);
490 	if (timer->card && timer->card->shutdown) {
491 		result = -ENODEV;
492 		goto unlock;
493 	}
494 	if (timeri->flags & (SNDRV_TIMER_IFLG_RUNNING |
495 			     SNDRV_TIMER_IFLG_START)) {
496 		result = -EBUSY;
497 		goto unlock;
498 	}
499 
500 	if (start)
501 		timeri->ticks = timeri->cticks = ticks;
502 	else if (!timeri->cticks)
503 		timeri->cticks = 1;
504 	timeri->pticks = 0;
505 
506 	list_move_tail(&timeri->active_list, &timer->active_list_head);
507 	if (timer->running) {
508 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
509 			goto __start_now;
510 		timer->flags |= SNDRV_TIMER_FLG_RESCHED;
511 		timeri->flags |= SNDRV_TIMER_IFLG_START;
512 		result = 1; /* delayed start */
513 	} else {
514 		if (start)
515 			timer->sticks = ticks;
516 		timer->hw.start(timer);
517 	      __start_now:
518 		timer->running++;
519 		timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
520 		result = 0;
521 	}
522 	snd_timer_notify1(timeri, start ? SNDRV_TIMER_EVENT_START :
523 			  SNDRV_TIMER_EVENT_CONTINUE);
524  unlock:
525 	spin_unlock_irqrestore(&timer->lock, flags);
526 	return result;
527 }
528 
529 /* start/continue a slave timer */
530 static int snd_timer_start_slave(struct snd_timer_instance *timeri,
531 				 bool start)
532 {
533 	unsigned long flags;
534 
535 	spin_lock_irqsave(&slave_active_lock, flags);
536 	if (timeri->flags & SNDRV_TIMER_IFLG_RUNNING) {
537 		spin_unlock_irqrestore(&slave_active_lock, flags);
538 		return -EBUSY;
539 	}
540 	timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
541 	if (timeri->master && timeri->timer) {
542 		spin_lock(&timeri->timer->lock);
543 		list_add_tail(&timeri->active_list,
544 			      &timeri->master->slave_active_head);
545 		snd_timer_notify1(timeri, start ? SNDRV_TIMER_EVENT_START :
546 				  SNDRV_TIMER_EVENT_CONTINUE);
547 		spin_unlock(&timeri->timer->lock);
548 	}
549 	spin_unlock_irqrestore(&slave_active_lock, flags);
550 	return 1; /* delayed start */
551 }
552 
553 /* stop/pause a master timer */
554 static int snd_timer_stop1(struct snd_timer_instance *timeri, bool stop)
555 {
556 	struct snd_timer *timer;
557 	int result = 0;
558 	unsigned long flags;
559 
560 	timer = timeri->timer;
561 	if (!timer)
562 		return -EINVAL;
563 	spin_lock_irqsave(&timer->lock, flags);
564 	if (!(timeri->flags & (SNDRV_TIMER_IFLG_RUNNING |
565 			       SNDRV_TIMER_IFLG_START))) {
566 		result = -EBUSY;
567 		goto unlock;
568 	}
569 	list_del_init(&timeri->ack_list);
570 	list_del_init(&timeri->active_list);
571 	if (timer->card && timer->card->shutdown)
572 		goto unlock;
573 	if (stop) {
574 		timeri->cticks = timeri->ticks;
575 		timeri->pticks = 0;
576 	}
577 	if ((timeri->flags & SNDRV_TIMER_IFLG_RUNNING) &&
578 	    !(--timer->running)) {
579 		timer->hw.stop(timer);
580 		if (timer->flags & SNDRV_TIMER_FLG_RESCHED) {
581 			timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
582 			snd_timer_reschedule(timer, 0);
583 			if (timer->flags & SNDRV_TIMER_FLG_CHANGE) {
584 				timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
585 				timer->hw.start(timer);
586 			}
587 		}
588 	}
589 	timeri->flags &= ~(SNDRV_TIMER_IFLG_RUNNING | SNDRV_TIMER_IFLG_START);
590 	if (stop)
591 		timeri->flags &= ~SNDRV_TIMER_IFLG_PAUSED;
592 	else
593 		timeri->flags |= SNDRV_TIMER_IFLG_PAUSED;
594 	snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :
595 			  SNDRV_TIMER_EVENT_CONTINUE);
596  unlock:
597 	spin_unlock_irqrestore(&timer->lock, flags);
598 	return result;
599 }
600 
601 /* stop/pause a slave timer */
602 static int snd_timer_stop_slave(struct snd_timer_instance *timeri, bool stop)
603 {
604 	unsigned long flags;
605 
606 	spin_lock_irqsave(&slave_active_lock, flags);
607 	if (!(timeri->flags & SNDRV_TIMER_IFLG_RUNNING)) {
608 		spin_unlock_irqrestore(&slave_active_lock, flags);
609 		return -EBUSY;
610 	}
611 	timeri->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
612 	if (timeri->timer) {
613 		spin_lock(&timeri->timer->lock);
614 		list_del_init(&timeri->ack_list);
615 		list_del_init(&timeri->active_list);
616 		snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :
617 				  SNDRV_TIMER_EVENT_CONTINUE);
618 		spin_unlock(&timeri->timer->lock);
619 	}
620 	spin_unlock_irqrestore(&slave_active_lock, flags);
621 	return 0;
622 }
623 
624 /*
625  *  start the timer instance
626  */
627 int snd_timer_start(struct snd_timer_instance *timeri, unsigned int ticks)
628 {
629 	if (timeri == NULL || ticks < 1)
630 		return -EINVAL;
631 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
632 		return snd_timer_start_slave(timeri, true);
633 	else
634 		return snd_timer_start1(timeri, true, ticks);
635 }
636 EXPORT_SYMBOL(snd_timer_start);
637 
638 /*
639  * stop the timer instance.
640  *
641  * do not call this from the timer callback!
642  */
643 int snd_timer_stop(struct snd_timer_instance *timeri)
644 {
645 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
646 		return snd_timer_stop_slave(timeri, true);
647 	else
648 		return snd_timer_stop1(timeri, true);
649 }
650 EXPORT_SYMBOL(snd_timer_stop);
651 
652 /*
653  * start again..  the tick is kept.
654  */
655 int snd_timer_continue(struct snd_timer_instance *timeri)
656 {
657 	/* timer can continue only after pause */
658 	if (!(timeri->flags & SNDRV_TIMER_IFLG_PAUSED))
659 		return -EINVAL;
660 
661 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
662 		return snd_timer_start_slave(timeri, false);
663 	else
664 		return snd_timer_start1(timeri, false, 0);
665 }
666 EXPORT_SYMBOL(snd_timer_continue);
667 
668 /*
669  * pause.. remember the ticks left
670  */
671 int snd_timer_pause(struct snd_timer_instance * timeri)
672 {
673 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
674 		return snd_timer_stop_slave(timeri, false);
675 	else
676 		return snd_timer_stop1(timeri, false);
677 }
678 EXPORT_SYMBOL(snd_timer_pause);
679 
680 /*
681  * reschedule the timer
682  *
683  * start pending instances and check the scheduling ticks.
684  * when the scheduling ticks is changed set CHANGE flag to reprogram the timer.
685  */
686 static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left)
687 {
688 	struct snd_timer_instance *ti;
689 	unsigned long ticks = ~0UL;
690 
691 	list_for_each_entry(ti, &timer->active_list_head, active_list) {
692 		if (ti->flags & SNDRV_TIMER_IFLG_START) {
693 			ti->flags &= ~SNDRV_TIMER_IFLG_START;
694 			ti->flags |= SNDRV_TIMER_IFLG_RUNNING;
695 			timer->running++;
696 		}
697 		if (ti->flags & SNDRV_TIMER_IFLG_RUNNING) {
698 			if (ticks > ti->cticks)
699 				ticks = ti->cticks;
700 		}
701 	}
702 	if (ticks == ~0UL) {
703 		timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
704 		return;
705 	}
706 	if (ticks > timer->hw.ticks)
707 		ticks = timer->hw.ticks;
708 	if (ticks_left != ticks)
709 		timer->flags |= SNDRV_TIMER_FLG_CHANGE;
710 	timer->sticks = ticks;
711 }
712 
713 /*
714  * timer tasklet
715  *
716  */
717 static void snd_timer_tasklet(unsigned long arg)
718 {
719 	struct snd_timer *timer = (struct snd_timer *) arg;
720 	struct snd_timer_instance *ti;
721 	struct list_head *p;
722 	unsigned long resolution, ticks;
723 	unsigned long flags;
724 
725 	if (timer->card && timer->card->shutdown)
726 		return;
727 
728 	spin_lock_irqsave(&timer->lock, flags);
729 	/* now process all callbacks */
730 	while (!list_empty(&timer->sack_list_head)) {
731 		p = timer->sack_list_head.next;		/* get first item */
732 		ti = list_entry(p, struct snd_timer_instance, ack_list);
733 
734 		/* remove from ack_list and make empty */
735 		list_del_init(p);
736 
737 		ticks = ti->pticks;
738 		ti->pticks = 0;
739 		resolution = ti->resolution;
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 	spin_unlock_irqrestore(&timer->lock, flags);
749 }
750 
751 /*
752  * timer interrupt
753  *
754  * ticks_left is usually equal to timer->sticks.
755  *
756  */
757 void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
758 {
759 	struct snd_timer_instance *ti, *ts, *tmp;
760 	unsigned long resolution, ticks;
761 	struct list_head *p, *ack_list_head;
762 	unsigned long flags;
763 	int use_tasklet = 0;
764 
765 	if (timer == NULL)
766 		return;
767 
768 	if (timer->card && timer->card->shutdown)
769 		return;
770 
771 	spin_lock_irqsave(&timer->lock, flags);
772 
773 	/* remember the current resolution */
774 	if (timer->hw.c_resolution)
775 		resolution = timer->hw.c_resolution(timer);
776 	else
777 		resolution = timer->hw.resolution;
778 
779 	/* loop for all active instances
780 	 * Here we cannot use list_for_each_entry because the active_list of a
781 	 * processed instance is relinked to done_list_head before the callback
782 	 * is called.
783 	 */
784 	list_for_each_entry_safe(ti, tmp, &timer->active_list_head,
785 				 active_list) {
786 		if (!(ti->flags & SNDRV_TIMER_IFLG_RUNNING))
787 			continue;
788 		ti->pticks += ticks_left;
789 		ti->resolution = resolution;
790 		if (ti->cticks < ticks_left)
791 			ti->cticks = 0;
792 		else
793 			ti->cticks -= ticks_left;
794 		if (ti->cticks) /* not expired */
795 			continue;
796 		if (ti->flags & SNDRV_TIMER_IFLG_AUTO) {
797 			ti->cticks = ti->ticks;
798 		} else {
799 			ti->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
800 			--timer->running;
801 			list_del_init(&ti->active_list);
802 		}
803 		if ((timer->hw.flags & SNDRV_TIMER_HW_TASKLET) ||
804 		    (ti->flags & SNDRV_TIMER_IFLG_FAST))
805 			ack_list_head = &timer->ack_list_head;
806 		else
807 			ack_list_head = &timer->sack_list_head;
808 		if (list_empty(&ti->ack_list))
809 			list_add_tail(&ti->ack_list, ack_list_head);
810 		list_for_each_entry(ts, &ti->slave_active_head, active_list) {
811 			ts->pticks = ti->pticks;
812 			ts->resolution = resolution;
813 			if (list_empty(&ts->ack_list))
814 				list_add_tail(&ts->ack_list, ack_list_head);
815 		}
816 	}
817 	if (timer->flags & SNDRV_TIMER_FLG_RESCHED)
818 		snd_timer_reschedule(timer, timer->sticks);
819 	if (timer->running) {
820 		if (timer->hw.flags & SNDRV_TIMER_HW_STOP) {
821 			timer->hw.stop(timer);
822 			timer->flags |= SNDRV_TIMER_FLG_CHANGE;
823 		}
824 		if (!(timer->hw.flags & SNDRV_TIMER_HW_AUTO) ||
825 		    (timer->flags & SNDRV_TIMER_FLG_CHANGE)) {
826 			/* restart timer */
827 			timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
828 			timer->hw.start(timer);
829 		}
830 	} else {
831 		timer->hw.stop(timer);
832 	}
833 
834 	/* now process all fast callbacks */
835 	while (!list_empty(&timer->ack_list_head)) {
836 		p = timer->ack_list_head.next;		/* get first item */
837 		ti = list_entry(p, struct snd_timer_instance, ack_list);
838 
839 		/* remove from ack_list and make empty */
840 		list_del_init(p);
841 
842 		ticks = ti->pticks;
843 		ti->pticks = 0;
844 
845 		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
846 		spin_unlock(&timer->lock);
847 		if (ti->callback)
848 			ti->callback(ti, resolution, ticks);
849 		spin_lock(&timer->lock);
850 		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
851 	}
852 
853 	/* do we have any slow callbacks? */
854 	use_tasklet = !list_empty(&timer->sack_list_head);
855 	spin_unlock_irqrestore(&timer->lock, flags);
856 
857 	if (use_tasklet)
858 		tasklet_schedule(&timer->task_queue);
859 }
860 EXPORT_SYMBOL(snd_timer_interrupt);
861 
862 /*
863 
864  */
865 
866 int snd_timer_new(struct snd_card *card, char *id, struct snd_timer_id *tid,
867 		  struct snd_timer **rtimer)
868 {
869 	struct snd_timer *timer;
870 	int err;
871 	static struct snd_device_ops ops = {
872 		.dev_free = snd_timer_dev_free,
873 		.dev_register = snd_timer_dev_register,
874 		.dev_disconnect = snd_timer_dev_disconnect,
875 	};
876 
877 	if (snd_BUG_ON(!tid))
878 		return -EINVAL;
879 	if (rtimer)
880 		*rtimer = NULL;
881 	timer = kzalloc(sizeof(*timer), GFP_KERNEL);
882 	if (!timer)
883 		return -ENOMEM;
884 	timer->tmr_class = tid->dev_class;
885 	timer->card = card;
886 	timer->tmr_device = tid->device;
887 	timer->tmr_subdevice = tid->subdevice;
888 	if (id)
889 		strlcpy(timer->id, id, sizeof(timer->id));
890 	timer->sticks = 1;
891 	INIT_LIST_HEAD(&timer->device_list);
892 	INIT_LIST_HEAD(&timer->open_list_head);
893 	INIT_LIST_HEAD(&timer->active_list_head);
894 	INIT_LIST_HEAD(&timer->ack_list_head);
895 	INIT_LIST_HEAD(&timer->sack_list_head);
896 	spin_lock_init(&timer->lock);
897 	tasklet_init(&timer->task_queue, snd_timer_tasklet,
898 		     (unsigned long)timer);
899 	timer->max_instances = 1000; /* default limit per timer */
900 	if (card != NULL) {
901 		timer->module = card->module;
902 		err = snd_device_new(card, SNDRV_DEV_TIMER, timer, &ops);
903 		if (err < 0) {
904 			snd_timer_free(timer);
905 			return err;
906 		}
907 	}
908 	if (rtimer)
909 		*rtimer = timer;
910 	return 0;
911 }
912 EXPORT_SYMBOL(snd_timer_new);
913 
914 static int snd_timer_free(struct snd_timer *timer)
915 {
916 	if (!timer)
917 		return 0;
918 
919 	mutex_lock(&register_mutex);
920 	if (! list_empty(&timer->open_list_head)) {
921 		struct list_head *p, *n;
922 		struct snd_timer_instance *ti;
923 		pr_warn("ALSA: timer %p is busy?\n", timer);
924 		list_for_each_safe(p, n, &timer->open_list_head) {
925 			list_del_init(p);
926 			ti = list_entry(p, struct snd_timer_instance, open_list);
927 			ti->timer = NULL;
928 		}
929 	}
930 	list_del(&timer->device_list);
931 	mutex_unlock(&register_mutex);
932 
933 	if (timer->private_free)
934 		timer->private_free(timer);
935 	kfree(timer);
936 	return 0;
937 }
938 
939 static int snd_timer_dev_free(struct snd_device *device)
940 {
941 	struct snd_timer *timer = device->device_data;
942 	return snd_timer_free(timer);
943 }
944 
945 static int snd_timer_dev_register(struct snd_device *dev)
946 {
947 	struct snd_timer *timer = dev->device_data;
948 	struct snd_timer *timer1;
949 
950 	if (snd_BUG_ON(!timer || !timer->hw.start || !timer->hw.stop))
951 		return -ENXIO;
952 	if (!(timer->hw.flags & SNDRV_TIMER_HW_SLAVE) &&
953 	    !timer->hw.resolution && timer->hw.c_resolution == NULL)
954 	    	return -EINVAL;
955 
956 	mutex_lock(&register_mutex);
957 	list_for_each_entry(timer1, &snd_timer_list, device_list) {
958 		if (timer1->tmr_class > timer->tmr_class)
959 			break;
960 		if (timer1->tmr_class < timer->tmr_class)
961 			continue;
962 		if (timer1->card && timer->card) {
963 			if (timer1->card->number > timer->card->number)
964 				break;
965 			if (timer1->card->number < timer->card->number)
966 				continue;
967 		}
968 		if (timer1->tmr_device > timer->tmr_device)
969 			break;
970 		if (timer1->tmr_device < timer->tmr_device)
971 			continue;
972 		if (timer1->tmr_subdevice > timer->tmr_subdevice)
973 			break;
974 		if (timer1->tmr_subdevice < timer->tmr_subdevice)
975 			continue;
976 		/* conflicts.. */
977 		mutex_unlock(&register_mutex);
978 		return -EBUSY;
979 	}
980 	list_add_tail(&timer->device_list, &timer1->device_list);
981 	mutex_unlock(&register_mutex);
982 	return 0;
983 }
984 
985 static int snd_timer_dev_disconnect(struct snd_device *device)
986 {
987 	struct snd_timer *timer = device->device_data;
988 	struct snd_timer_instance *ti;
989 
990 	mutex_lock(&register_mutex);
991 	list_del_init(&timer->device_list);
992 	/* wake up pending sleepers */
993 	list_for_each_entry(ti, &timer->open_list_head, open_list) {
994 		if (ti->disconnect)
995 			ti->disconnect(ti);
996 	}
997 	mutex_unlock(&register_mutex);
998 	return 0;
999 }
1000 
1001 void snd_timer_notify(struct snd_timer *timer, int event, struct timespec *tstamp)
1002 {
1003 	unsigned long flags;
1004 	unsigned long resolution = 0;
1005 	struct snd_timer_instance *ti, *ts;
1006 
1007 	if (timer->card && timer->card->shutdown)
1008 		return;
1009 	if (! (timer->hw.flags & SNDRV_TIMER_HW_SLAVE))
1010 		return;
1011 	if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_MSTART ||
1012 		       event > SNDRV_TIMER_EVENT_MRESUME))
1013 		return;
1014 	spin_lock_irqsave(&timer->lock, flags);
1015 	if (event == SNDRV_TIMER_EVENT_MSTART ||
1016 	    event == SNDRV_TIMER_EVENT_MCONTINUE ||
1017 	    event == SNDRV_TIMER_EVENT_MRESUME) {
1018 		if (timer->hw.c_resolution)
1019 			resolution = timer->hw.c_resolution(timer);
1020 		else
1021 			resolution = timer->hw.resolution;
1022 	}
1023 	list_for_each_entry(ti, &timer->active_list_head, active_list) {
1024 		if (ti->ccallback)
1025 			ti->ccallback(ti, event, tstamp, resolution);
1026 		list_for_each_entry(ts, &ti->slave_active_head, active_list)
1027 			if (ts->ccallback)
1028 				ts->ccallback(ts, event, tstamp, resolution);
1029 	}
1030 	spin_unlock_irqrestore(&timer->lock, flags);
1031 }
1032 EXPORT_SYMBOL(snd_timer_notify);
1033 
1034 /*
1035  * exported functions for global timers
1036  */
1037 int snd_timer_global_new(char *id, int device, struct snd_timer **rtimer)
1038 {
1039 	struct snd_timer_id tid;
1040 
1041 	tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
1042 	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1043 	tid.card = -1;
1044 	tid.device = device;
1045 	tid.subdevice = 0;
1046 	return snd_timer_new(NULL, id, &tid, rtimer);
1047 }
1048 EXPORT_SYMBOL(snd_timer_global_new);
1049 
1050 int snd_timer_global_free(struct snd_timer *timer)
1051 {
1052 	return snd_timer_free(timer);
1053 }
1054 EXPORT_SYMBOL(snd_timer_global_free);
1055 
1056 int snd_timer_global_register(struct snd_timer *timer)
1057 {
1058 	struct snd_device dev;
1059 
1060 	memset(&dev, 0, sizeof(dev));
1061 	dev.device_data = timer;
1062 	return snd_timer_dev_register(&dev);
1063 }
1064 EXPORT_SYMBOL(snd_timer_global_register);
1065 
1066 /*
1067  *  System timer
1068  */
1069 
1070 struct snd_timer_system_private {
1071 	struct timer_list tlist;
1072 	unsigned long last_expires;
1073 	unsigned long last_jiffies;
1074 	unsigned long correction;
1075 };
1076 
1077 static void snd_timer_s_function(unsigned long data)
1078 {
1079 	struct snd_timer *timer = (struct snd_timer *)data;
1080 	struct snd_timer_system_private *priv = timer->private_data;
1081 	unsigned long jiff = jiffies;
1082 	if (time_after(jiff, priv->last_expires))
1083 		priv->correction += (long)jiff - (long)priv->last_expires;
1084 	snd_timer_interrupt(timer, (long)jiff - (long)priv->last_jiffies);
1085 }
1086 
1087 static int snd_timer_s_start(struct snd_timer * timer)
1088 {
1089 	struct snd_timer_system_private *priv;
1090 	unsigned long njiff;
1091 
1092 	priv = (struct snd_timer_system_private *) timer->private_data;
1093 	njiff = (priv->last_jiffies = jiffies);
1094 	if (priv->correction > timer->sticks - 1) {
1095 		priv->correction -= timer->sticks - 1;
1096 		njiff++;
1097 	} else {
1098 		njiff += timer->sticks - priv->correction;
1099 		priv->correction = 0;
1100 	}
1101 	priv->last_expires = njiff;
1102 	mod_timer(&priv->tlist, njiff);
1103 	return 0;
1104 }
1105 
1106 static int snd_timer_s_stop(struct snd_timer * timer)
1107 {
1108 	struct snd_timer_system_private *priv;
1109 	unsigned long jiff;
1110 
1111 	priv = (struct snd_timer_system_private *) timer->private_data;
1112 	del_timer(&priv->tlist);
1113 	jiff = jiffies;
1114 	if (time_before(jiff, priv->last_expires))
1115 		timer->sticks = priv->last_expires - jiff;
1116 	else
1117 		timer->sticks = 1;
1118 	priv->correction = 0;
1119 	return 0;
1120 }
1121 
1122 static int snd_timer_s_close(struct snd_timer *timer)
1123 {
1124 	struct snd_timer_system_private *priv;
1125 
1126 	priv = (struct snd_timer_system_private *)timer->private_data;
1127 	del_timer_sync(&priv->tlist);
1128 	return 0;
1129 }
1130 
1131 static struct snd_timer_hardware snd_timer_system =
1132 {
1133 	.flags =	SNDRV_TIMER_HW_FIRST | SNDRV_TIMER_HW_TASKLET,
1134 	.resolution =	1000000000L / HZ,
1135 	.ticks =	10000000L,
1136 	.close =	snd_timer_s_close,
1137 	.start =	snd_timer_s_start,
1138 	.stop =		snd_timer_s_stop
1139 };
1140 
1141 static void snd_timer_free_system(struct snd_timer *timer)
1142 {
1143 	kfree(timer->private_data);
1144 }
1145 
1146 static int snd_timer_register_system(void)
1147 {
1148 	struct snd_timer *timer;
1149 	struct snd_timer_system_private *priv;
1150 	int err;
1151 
1152 	err = snd_timer_global_new("system", SNDRV_TIMER_GLOBAL_SYSTEM, &timer);
1153 	if (err < 0)
1154 		return err;
1155 	strcpy(timer->name, "system timer");
1156 	timer->hw = snd_timer_system;
1157 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1158 	if (priv == NULL) {
1159 		snd_timer_free(timer);
1160 		return -ENOMEM;
1161 	}
1162 	setup_timer(&priv->tlist, snd_timer_s_function, (unsigned long) timer);
1163 	timer->private_data = priv;
1164 	timer->private_free = snd_timer_free_system;
1165 	return snd_timer_global_register(timer);
1166 }
1167 
1168 #ifdef CONFIG_SND_PROC_FS
1169 /*
1170  *  Info interface
1171  */
1172 
1173 static void snd_timer_proc_read(struct snd_info_entry *entry,
1174 				struct snd_info_buffer *buffer)
1175 {
1176 	struct snd_timer *timer;
1177 	struct snd_timer_instance *ti;
1178 
1179 	mutex_lock(&register_mutex);
1180 	list_for_each_entry(timer, &snd_timer_list, device_list) {
1181 		if (timer->card && timer->card->shutdown)
1182 			continue;
1183 		switch (timer->tmr_class) {
1184 		case SNDRV_TIMER_CLASS_GLOBAL:
1185 			snd_iprintf(buffer, "G%i: ", timer->tmr_device);
1186 			break;
1187 		case SNDRV_TIMER_CLASS_CARD:
1188 			snd_iprintf(buffer, "C%i-%i: ",
1189 				    timer->card->number, timer->tmr_device);
1190 			break;
1191 		case SNDRV_TIMER_CLASS_PCM:
1192 			snd_iprintf(buffer, "P%i-%i-%i: ", timer->card->number,
1193 				    timer->tmr_device, timer->tmr_subdevice);
1194 			break;
1195 		default:
1196 			snd_iprintf(buffer, "?%i-%i-%i-%i: ", timer->tmr_class,
1197 				    timer->card ? timer->card->number : -1,
1198 				    timer->tmr_device, timer->tmr_subdevice);
1199 		}
1200 		snd_iprintf(buffer, "%s :", timer->name);
1201 		if (timer->hw.resolution)
1202 			snd_iprintf(buffer, " %lu.%03luus (%lu ticks)",
1203 				    timer->hw.resolution / 1000,
1204 				    timer->hw.resolution % 1000,
1205 				    timer->hw.ticks);
1206 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
1207 			snd_iprintf(buffer, " SLAVE");
1208 		snd_iprintf(buffer, "\n");
1209 		list_for_each_entry(ti, &timer->open_list_head, open_list)
1210 			snd_iprintf(buffer, "  Client %s : %s\n",
1211 				    ti->owner ? ti->owner : "unknown",
1212 				    ti->flags & (SNDRV_TIMER_IFLG_START |
1213 						 SNDRV_TIMER_IFLG_RUNNING)
1214 				    ? "running" : "stopped");
1215 	}
1216 	mutex_unlock(&register_mutex);
1217 }
1218 
1219 static struct snd_info_entry *snd_timer_proc_entry;
1220 
1221 static void __init snd_timer_proc_init(void)
1222 {
1223 	struct snd_info_entry *entry;
1224 
1225 	entry = snd_info_create_module_entry(THIS_MODULE, "timers", NULL);
1226 	if (entry != NULL) {
1227 		entry->c.text.read = snd_timer_proc_read;
1228 		if (snd_info_register(entry) < 0) {
1229 			snd_info_free_entry(entry);
1230 			entry = NULL;
1231 		}
1232 	}
1233 	snd_timer_proc_entry = entry;
1234 }
1235 
1236 static void __exit snd_timer_proc_done(void)
1237 {
1238 	snd_info_free_entry(snd_timer_proc_entry);
1239 }
1240 #else /* !CONFIG_SND_PROC_FS */
1241 #define snd_timer_proc_init()
1242 #define snd_timer_proc_done()
1243 #endif
1244 
1245 /*
1246  *  USER SPACE interface
1247  */
1248 
1249 static void snd_timer_user_interrupt(struct snd_timer_instance *timeri,
1250 				     unsigned long resolution,
1251 				     unsigned long ticks)
1252 {
1253 	struct snd_timer_user *tu = timeri->callback_data;
1254 	struct snd_timer_read *r;
1255 	int prev;
1256 
1257 	spin_lock(&tu->qlock);
1258 	if (tu->qused > 0) {
1259 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1260 		r = &tu->queue[prev];
1261 		if (r->resolution == resolution) {
1262 			r->ticks += ticks;
1263 			goto __wake;
1264 		}
1265 	}
1266 	if (tu->qused >= tu->queue_size) {
1267 		tu->overrun++;
1268 	} else {
1269 		r = &tu->queue[tu->qtail++];
1270 		tu->qtail %= tu->queue_size;
1271 		r->resolution = resolution;
1272 		r->ticks = ticks;
1273 		tu->qused++;
1274 	}
1275       __wake:
1276 	spin_unlock(&tu->qlock);
1277 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1278 	wake_up(&tu->qchange_sleep);
1279 }
1280 
1281 static void snd_timer_user_append_to_tqueue(struct snd_timer_user *tu,
1282 					    struct snd_timer_tread *tread)
1283 {
1284 	if (tu->qused >= tu->queue_size) {
1285 		tu->overrun++;
1286 	} else {
1287 		memcpy(&tu->tqueue[tu->qtail++], tread, sizeof(*tread));
1288 		tu->qtail %= tu->queue_size;
1289 		tu->qused++;
1290 	}
1291 }
1292 
1293 static void snd_timer_user_ccallback(struct snd_timer_instance *timeri,
1294 				     int event,
1295 				     struct timespec *tstamp,
1296 				     unsigned long resolution)
1297 {
1298 	struct snd_timer_user *tu = timeri->callback_data;
1299 	struct snd_timer_tread r1;
1300 	unsigned long flags;
1301 
1302 	if (event >= SNDRV_TIMER_EVENT_START &&
1303 	    event <= SNDRV_TIMER_EVENT_PAUSE)
1304 		tu->tstamp = *tstamp;
1305 	if ((tu->filter & (1 << event)) == 0 || !tu->tread)
1306 		return;
1307 	memset(&r1, 0, sizeof(r1));
1308 	r1.event = event;
1309 	r1.tstamp = *tstamp;
1310 	r1.val = resolution;
1311 	spin_lock_irqsave(&tu->qlock, flags);
1312 	snd_timer_user_append_to_tqueue(tu, &r1);
1313 	spin_unlock_irqrestore(&tu->qlock, flags);
1314 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1315 	wake_up(&tu->qchange_sleep);
1316 }
1317 
1318 static void snd_timer_user_disconnect(struct snd_timer_instance *timeri)
1319 {
1320 	struct snd_timer_user *tu = timeri->callback_data;
1321 
1322 	tu->disconnected = true;
1323 	wake_up(&tu->qchange_sleep);
1324 }
1325 
1326 static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
1327 				      unsigned long resolution,
1328 				      unsigned long ticks)
1329 {
1330 	struct snd_timer_user *tu = timeri->callback_data;
1331 	struct snd_timer_tread *r, r1;
1332 	struct timespec tstamp;
1333 	int prev, append = 0;
1334 
1335 	memset(&r1, 0, sizeof(r1));
1336 	memset(&tstamp, 0, sizeof(tstamp));
1337 	spin_lock(&tu->qlock);
1338 	if ((tu->filter & ((1 << SNDRV_TIMER_EVENT_RESOLUTION) |
1339 			   (1 << SNDRV_TIMER_EVENT_TICK))) == 0) {
1340 		spin_unlock(&tu->qlock);
1341 		return;
1342 	}
1343 	if (tu->last_resolution != resolution || ticks > 0) {
1344 		if (timer_tstamp_monotonic)
1345 			ktime_get_ts(&tstamp);
1346 		else
1347 			getnstimeofday(&tstamp);
1348 	}
1349 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_RESOLUTION)) &&
1350 	    tu->last_resolution != resolution) {
1351 		r1.event = SNDRV_TIMER_EVENT_RESOLUTION;
1352 		r1.tstamp = tstamp;
1353 		r1.val = resolution;
1354 		snd_timer_user_append_to_tqueue(tu, &r1);
1355 		tu->last_resolution = resolution;
1356 		append++;
1357 	}
1358 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_TICK)) == 0)
1359 		goto __wake;
1360 	if (ticks == 0)
1361 		goto __wake;
1362 	if (tu->qused > 0) {
1363 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1364 		r = &tu->tqueue[prev];
1365 		if (r->event == SNDRV_TIMER_EVENT_TICK) {
1366 			r->tstamp = tstamp;
1367 			r->val += ticks;
1368 			append++;
1369 			goto __wake;
1370 		}
1371 	}
1372 	r1.event = SNDRV_TIMER_EVENT_TICK;
1373 	r1.tstamp = tstamp;
1374 	r1.val = ticks;
1375 	snd_timer_user_append_to_tqueue(tu, &r1);
1376 	append++;
1377       __wake:
1378 	spin_unlock(&tu->qlock);
1379 	if (append == 0)
1380 		return;
1381 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1382 	wake_up(&tu->qchange_sleep);
1383 }
1384 
1385 static int realloc_user_queue(struct snd_timer_user *tu, int size)
1386 {
1387 	struct snd_timer_read *queue = NULL;
1388 	struct snd_timer_tread *tqueue = NULL;
1389 
1390 	if (tu->tread) {
1391 		tqueue = kcalloc(size, sizeof(*tqueue), GFP_KERNEL);
1392 		if (!tqueue)
1393 			return -ENOMEM;
1394 	} else {
1395 		queue = kcalloc(size, sizeof(*queue), GFP_KERNEL);
1396 		if (!queue)
1397 			return -ENOMEM;
1398 	}
1399 
1400 	spin_lock_irq(&tu->qlock);
1401 	kfree(tu->queue);
1402 	kfree(tu->tqueue);
1403 	tu->queue_size = size;
1404 	tu->queue = queue;
1405 	tu->tqueue = tqueue;
1406 	tu->qhead = tu->qtail = tu->qused = 0;
1407 	spin_unlock_irq(&tu->qlock);
1408 
1409 	return 0;
1410 }
1411 
1412 static int snd_timer_user_open(struct inode *inode, struct file *file)
1413 {
1414 	struct snd_timer_user *tu;
1415 	int err;
1416 
1417 	err = nonseekable_open(inode, file);
1418 	if (err < 0)
1419 		return err;
1420 
1421 	tu = kzalloc(sizeof(*tu), GFP_KERNEL);
1422 	if (tu == NULL)
1423 		return -ENOMEM;
1424 	spin_lock_init(&tu->qlock);
1425 	init_waitqueue_head(&tu->qchange_sleep);
1426 	mutex_init(&tu->ioctl_lock);
1427 	tu->ticks = 1;
1428 	if (realloc_user_queue(tu, 128) < 0) {
1429 		kfree(tu);
1430 		return -ENOMEM;
1431 	}
1432 	file->private_data = tu;
1433 	return 0;
1434 }
1435 
1436 static int snd_timer_user_release(struct inode *inode, struct file *file)
1437 {
1438 	struct snd_timer_user *tu;
1439 
1440 	if (file->private_data) {
1441 		tu = file->private_data;
1442 		file->private_data = NULL;
1443 		mutex_lock(&tu->ioctl_lock);
1444 		if (tu->timeri)
1445 			snd_timer_close(tu->timeri);
1446 		mutex_unlock(&tu->ioctl_lock);
1447 		kfree(tu->queue);
1448 		kfree(tu->tqueue);
1449 		kfree(tu);
1450 	}
1451 	return 0;
1452 }
1453 
1454 static void snd_timer_user_zero_id(struct snd_timer_id *id)
1455 {
1456 	id->dev_class = SNDRV_TIMER_CLASS_NONE;
1457 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1458 	id->card = -1;
1459 	id->device = -1;
1460 	id->subdevice = -1;
1461 }
1462 
1463 static void snd_timer_user_copy_id(struct snd_timer_id *id, struct snd_timer *timer)
1464 {
1465 	id->dev_class = timer->tmr_class;
1466 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1467 	id->card = timer->card ? timer->card->number : -1;
1468 	id->device = timer->tmr_device;
1469 	id->subdevice = timer->tmr_subdevice;
1470 }
1471 
1472 static int snd_timer_user_next_device(struct snd_timer_id __user *_tid)
1473 {
1474 	struct snd_timer_id id;
1475 	struct snd_timer *timer;
1476 	struct list_head *p;
1477 
1478 	if (copy_from_user(&id, _tid, sizeof(id)))
1479 		return -EFAULT;
1480 	mutex_lock(&register_mutex);
1481 	if (id.dev_class < 0) {		/* first item */
1482 		if (list_empty(&snd_timer_list))
1483 			snd_timer_user_zero_id(&id);
1484 		else {
1485 			timer = list_entry(snd_timer_list.next,
1486 					   struct snd_timer, device_list);
1487 			snd_timer_user_copy_id(&id, timer);
1488 		}
1489 	} else {
1490 		switch (id.dev_class) {
1491 		case SNDRV_TIMER_CLASS_GLOBAL:
1492 			id.device = id.device < 0 ? 0 : id.device + 1;
1493 			list_for_each(p, &snd_timer_list) {
1494 				timer = list_entry(p, struct snd_timer, device_list);
1495 				if (timer->tmr_class > SNDRV_TIMER_CLASS_GLOBAL) {
1496 					snd_timer_user_copy_id(&id, timer);
1497 					break;
1498 				}
1499 				if (timer->tmr_device >= id.device) {
1500 					snd_timer_user_copy_id(&id, timer);
1501 					break;
1502 				}
1503 			}
1504 			if (p == &snd_timer_list)
1505 				snd_timer_user_zero_id(&id);
1506 			break;
1507 		case SNDRV_TIMER_CLASS_CARD:
1508 		case SNDRV_TIMER_CLASS_PCM:
1509 			if (id.card < 0) {
1510 				id.card = 0;
1511 			} else {
1512 				if (id.device < 0) {
1513 					id.device = 0;
1514 				} else {
1515 					if (id.subdevice < 0)
1516 						id.subdevice = 0;
1517 					else
1518 						id.subdevice++;
1519 				}
1520 			}
1521 			list_for_each(p, &snd_timer_list) {
1522 				timer = list_entry(p, struct snd_timer, device_list);
1523 				if (timer->tmr_class > id.dev_class) {
1524 					snd_timer_user_copy_id(&id, timer);
1525 					break;
1526 				}
1527 				if (timer->tmr_class < id.dev_class)
1528 					continue;
1529 				if (timer->card->number > id.card) {
1530 					snd_timer_user_copy_id(&id, timer);
1531 					break;
1532 				}
1533 				if (timer->card->number < id.card)
1534 					continue;
1535 				if (timer->tmr_device > id.device) {
1536 					snd_timer_user_copy_id(&id, timer);
1537 					break;
1538 				}
1539 				if (timer->tmr_device < id.device)
1540 					continue;
1541 				if (timer->tmr_subdevice > id.subdevice) {
1542 					snd_timer_user_copy_id(&id, timer);
1543 					break;
1544 				}
1545 				if (timer->tmr_subdevice < id.subdevice)
1546 					continue;
1547 				snd_timer_user_copy_id(&id, timer);
1548 				break;
1549 			}
1550 			if (p == &snd_timer_list)
1551 				snd_timer_user_zero_id(&id);
1552 			break;
1553 		default:
1554 			snd_timer_user_zero_id(&id);
1555 		}
1556 	}
1557 	mutex_unlock(&register_mutex);
1558 	if (copy_to_user(_tid, &id, sizeof(*_tid)))
1559 		return -EFAULT;
1560 	return 0;
1561 }
1562 
1563 static int snd_timer_user_ginfo(struct file *file,
1564 				struct snd_timer_ginfo __user *_ginfo)
1565 {
1566 	struct snd_timer_ginfo *ginfo;
1567 	struct snd_timer_id tid;
1568 	struct snd_timer *t;
1569 	struct list_head *p;
1570 	int err = 0;
1571 
1572 	ginfo = memdup_user(_ginfo, sizeof(*ginfo));
1573 	if (IS_ERR(ginfo))
1574 		return PTR_ERR(ginfo);
1575 
1576 	tid = ginfo->tid;
1577 	memset(ginfo, 0, sizeof(*ginfo));
1578 	ginfo->tid = tid;
1579 	mutex_lock(&register_mutex);
1580 	t = snd_timer_find(&tid);
1581 	if (t != NULL) {
1582 		ginfo->card = t->card ? t->card->number : -1;
1583 		if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1584 			ginfo->flags |= SNDRV_TIMER_FLG_SLAVE;
1585 		strlcpy(ginfo->id, t->id, sizeof(ginfo->id));
1586 		strlcpy(ginfo->name, t->name, sizeof(ginfo->name));
1587 		ginfo->resolution = t->hw.resolution;
1588 		if (t->hw.resolution_min > 0) {
1589 			ginfo->resolution_min = t->hw.resolution_min;
1590 			ginfo->resolution_max = t->hw.resolution_max;
1591 		}
1592 		list_for_each(p, &t->open_list_head) {
1593 			ginfo->clients++;
1594 		}
1595 	} else {
1596 		err = -ENODEV;
1597 	}
1598 	mutex_unlock(&register_mutex);
1599 	if (err >= 0 && copy_to_user(_ginfo, ginfo, sizeof(*ginfo)))
1600 		err = -EFAULT;
1601 	kfree(ginfo);
1602 	return err;
1603 }
1604 
1605 static int timer_set_gparams(struct snd_timer_gparams *gparams)
1606 {
1607 	struct snd_timer *t;
1608 	int err;
1609 
1610 	mutex_lock(&register_mutex);
1611 	t = snd_timer_find(&gparams->tid);
1612 	if (!t) {
1613 		err = -ENODEV;
1614 		goto _error;
1615 	}
1616 	if (!list_empty(&t->open_list_head)) {
1617 		err = -EBUSY;
1618 		goto _error;
1619 	}
1620 	if (!t->hw.set_period) {
1621 		err = -ENOSYS;
1622 		goto _error;
1623 	}
1624 	err = t->hw.set_period(t, gparams->period_num, gparams->period_den);
1625 _error:
1626 	mutex_unlock(&register_mutex);
1627 	return err;
1628 }
1629 
1630 static int snd_timer_user_gparams(struct file *file,
1631 				  struct snd_timer_gparams __user *_gparams)
1632 {
1633 	struct snd_timer_gparams gparams;
1634 
1635 	if (copy_from_user(&gparams, _gparams, sizeof(gparams)))
1636 		return -EFAULT;
1637 	return timer_set_gparams(&gparams);
1638 }
1639 
1640 static int snd_timer_user_gstatus(struct file *file,
1641 				  struct snd_timer_gstatus __user *_gstatus)
1642 {
1643 	struct snd_timer_gstatus gstatus;
1644 	struct snd_timer_id tid;
1645 	struct snd_timer *t;
1646 	int err = 0;
1647 
1648 	if (copy_from_user(&gstatus, _gstatus, sizeof(gstatus)))
1649 		return -EFAULT;
1650 	tid = gstatus.tid;
1651 	memset(&gstatus, 0, sizeof(gstatus));
1652 	gstatus.tid = tid;
1653 	mutex_lock(&register_mutex);
1654 	t = snd_timer_find(&tid);
1655 	if (t != NULL) {
1656 		if (t->hw.c_resolution)
1657 			gstatus.resolution = t->hw.c_resolution(t);
1658 		else
1659 			gstatus.resolution = t->hw.resolution;
1660 		if (t->hw.precise_resolution) {
1661 			t->hw.precise_resolution(t, &gstatus.resolution_num,
1662 						 &gstatus.resolution_den);
1663 		} else {
1664 			gstatus.resolution_num = gstatus.resolution;
1665 			gstatus.resolution_den = 1000000000uL;
1666 		}
1667 	} else {
1668 		err = -ENODEV;
1669 	}
1670 	mutex_unlock(&register_mutex);
1671 	if (err >= 0 && copy_to_user(_gstatus, &gstatus, sizeof(gstatus)))
1672 		err = -EFAULT;
1673 	return err;
1674 }
1675 
1676 static int snd_timer_user_tselect(struct file *file,
1677 				  struct snd_timer_select __user *_tselect)
1678 {
1679 	struct snd_timer_user *tu;
1680 	struct snd_timer_select tselect;
1681 	char str[32];
1682 	int err = 0;
1683 
1684 	tu = file->private_data;
1685 	if (tu->timeri) {
1686 		snd_timer_close(tu->timeri);
1687 		tu->timeri = NULL;
1688 	}
1689 	if (copy_from_user(&tselect, _tselect, sizeof(tselect))) {
1690 		err = -EFAULT;
1691 		goto __err;
1692 	}
1693 	sprintf(str, "application %i", current->pid);
1694 	if (tselect.id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
1695 		tselect.id.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION;
1696 	err = snd_timer_open(&tu->timeri, str, &tselect.id, current->pid);
1697 	if (err < 0)
1698 		goto __err;
1699 
1700 	tu->timeri->flags |= SNDRV_TIMER_IFLG_FAST;
1701 	tu->timeri->callback = tu->tread
1702 			? snd_timer_user_tinterrupt : snd_timer_user_interrupt;
1703 	tu->timeri->ccallback = snd_timer_user_ccallback;
1704 	tu->timeri->callback_data = (void *)tu;
1705 	tu->timeri->disconnect = snd_timer_user_disconnect;
1706 
1707       __err:
1708 	return err;
1709 }
1710 
1711 static int snd_timer_user_info(struct file *file,
1712 			       struct snd_timer_info __user *_info)
1713 {
1714 	struct snd_timer_user *tu;
1715 	struct snd_timer_info *info;
1716 	struct snd_timer *t;
1717 	int err = 0;
1718 
1719 	tu = file->private_data;
1720 	if (!tu->timeri)
1721 		return -EBADFD;
1722 	t = tu->timeri->timer;
1723 	if (!t)
1724 		return -EBADFD;
1725 
1726 	info = kzalloc(sizeof(*info), GFP_KERNEL);
1727 	if (! info)
1728 		return -ENOMEM;
1729 	info->card = t->card ? t->card->number : -1;
1730 	if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1731 		info->flags |= SNDRV_TIMER_FLG_SLAVE;
1732 	strlcpy(info->id, t->id, sizeof(info->id));
1733 	strlcpy(info->name, t->name, sizeof(info->name));
1734 	info->resolution = t->hw.resolution;
1735 	if (copy_to_user(_info, info, sizeof(*_info)))
1736 		err = -EFAULT;
1737 	kfree(info);
1738 	return err;
1739 }
1740 
1741 static int snd_timer_user_params(struct file *file,
1742 				 struct snd_timer_params __user *_params)
1743 {
1744 	struct snd_timer_user *tu;
1745 	struct snd_timer_params params;
1746 	struct snd_timer *t;
1747 	int err;
1748 
1749 	tu = file->private_data;
1750 	if (!tu->timeri)
1751 		return -EBADFD;
1752 	t = tu->timeri->timer;
1753 	if (!t)
1754 		return -EBADFD;
1755 	if (copy_from_user(&params, _params, sizeof(params)))
1756 		return -EFAULT;
1757 	if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE)) {
1758 		u64 resolution;
1759 
1760 		if (params.ticks < 1) {
1761 			err = -EINVAL;
1762 			goto _end;
1763 		}
1764 
1765 		/* Don't allow resolution less than 1ms */
1766 		resolution = snd_timer_resolution(tu->timeri);
1767 		resolution *= params.ticks;
1768 		if (resolution < 1000000) {
1769 			err = -EINVAL;
1770 			goto _end;
1771 		}
1772 	}
1773 	if (params.queue_size > 0 &&
1774 	    (params.queue_size < 32 || params.queue_size > 1024)) {
1775 		err = -EINVAL;
1776 		goto _end;
1777 	}
1778 	if (params.filter & ~((1<<SNDRV_TIMER_EVENT_RESOLUTION)|
1779 			      (1<<SNDRV_TIMER_EVENT_TICK)|
1780 			      (1<<SNDRV_TIMER_EVENT_START)|
1781 			      (1<<SNDRV_TIMER_EVENT_STOP)|
1782 			      (1<<SNDRV_TIMER_EVENT_CONTINUE)|
1783 			      (1<<SNDRV_TIMER_EVENT_PAUSE)|
1784 			      (1<<SNDRV_TIMER_EVENT_SUSPEND)|
1785 			      (1<<SNDRV_TIMER_EVENT_RESUME)|
1786 			      (1<<SNDRV_TIMER_EVENT_MSTART)|
1787 			      (1<<SNDRV_TIMER_EVENT_MSTOP)|
1788 			      (1<<SNDRV_TIMER_EVENT_MCONTINUE)|
1789 			      (1<<SNDRV_TIMER_EVENT_MPAUSE)|
1790 			      (1<<SNDRV_TIMER_EVENT_MSUSPEND)|
1791 			      (1<<SNDRV_TIMER_EVENT_MRESUME))) {
1792 		err = -EINVAL;
1793 		goto _end;
1794 	}
1795 	snd_timer_stop(tu->timeri);
1796 	spin_lock_irq(&t->lock);
1797 	tu->timeri->flags &= ~(SNDRV_TIMER_IFLG_AUTO|
1798 			       SNDRV_TIMER_IFLG_EXCLUSIVE|
1799 			       SNDRV_TIMER_IFLG_EARLY_EVENT);
1800 	if (params.flags & SNDRV_TIMER_PSFLG_AUTO)
1801 		tu->timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1802 	if (params.flags & SNDRV_TIMER_PSFLG_EXCLUSIVE)
1803 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EXCLUSIVE;
1804 	if (params.flags & SNDRV_TIMER_PSFLG_EARLY_EVENT)
1805 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EARLY_EVENT;
1806 	spin_unlock_irq(&t->lock);
1807 	if (params.queue_size > 0 &&
1808 	    (unsigned int)tu->queue_size != params.queue_size) {
1809 		err = realloc_user_queue(tu, params.queue_size);
1810 		if (err < 0)
1811 			goto _end;
1812 	}
1813 	spin_lock_irq(&tu->qlock);
1814 	tu->qhead = tu->qtail = tu->qused = 0;
1815 	if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
1816 		if (tu->tread) {
1817 			struct snd_timer_tread tread;
1818 			memset(&tread, 0, sizeof(tread));
1819 			tread.event = SNDRV_TIMER_EVENT_EARLY;
1820 			tread.tstamp.tv_sec = 0;
1821 			tread.tstamp.tv_nsec = 0;
1822 			tread.val = 0;
1823 			snd_timer_user_append_to_tqueue(tu, &tread);
1824 		} else {
1825 			struct snd_timer_read *r = &tu->queue[0];
1826 			r->resolution = 0;
1827 			r->ticks = 0;
1828 			tu->qused++;
1829 			tu->qtail++;
1830 		}
1831 	}
1832 	tu->filter = params.filter;
1833 	tu->ticks = params.ticks;
1834 	spin_unlock_irq(&tu->qlock);
1835 	err = 0;
1836  _end:
1837 	if (copy_to_user(_params, &params, sizeof(params)))
1838 		return -EFAULT;
1839 	return err;
1840 }
1841 
1842 static int snd_timer_user_status(struct file *file,
1843 				 struct snd_timer_status __user *_status)
1844 {
1845 	struct snd_timer_user *tu;
1846 	struct snd_timer_status status;
1847 
1848 	tu = file->private_data;
1849 	if (!tu->timeri)
1850 		return -EBADFD;
1851 	memset(&status, 0, sizeof(status));
1852 	status.tstamp = tu->tstamp;
1853 	status.resolution = snd_timer_resolution(tu->timeri);
1854 	status.lost = tu->timeri->lost;
1855 	status.overrun = tu->overrun;
1856 	spin_lock_irq(&tu->qlock);
1857 	status.queue = tu->qused;
1858 	spin_unlock_irq(&tu->qlock);
1859 	if (copy_to_user(_status, &status, sizeof(status)))
1860 		return -EFAULT;
1861 	return 0;
1862 }
1863 
1864 static int snd_timer_user_start(struct file *file)
1865 {
1866 	int err;
1867 	struct snd_timer_user *tu;
1868 
1869 	tu = file->private_data;
1870 	if (!tu->timeri)
1871 		return -EBADFD;
1872 	snd_timer_stop(tu->timeri);
1873 	tu->timeri->lost = 0;
1874 	tu->last_resolution = 0;
1875 	return (err = snd_timer_start(tu->timeri, tu->ticks)) < 0 ? err : 0;
1876 }
1877 
1878 static int snd_timer_user_stop(struct file *file)
1879 {
1880 	int err;
1881 	struct snd_timer_user *tu;
1882 
1883 	tu = file->private_data;
1884 	if (!tu->timeri)
1885 		return -EBADFD;
1886 	return (err = snd_timer_stop(tu->timeri)) < 0 ? err : 0;
1887 }
1888 
1889 static int snd_timer_user_continue(struct file *file)
1890 {
1891 	int err;
1892 	struct snd_timer_user *tu;
1893 
1894 	tu = file->private_data;
1895 	if (!tu->timeri)
1896 		return -EBADFD;
1897 	/* start timer instead of continue if it's not used before */
1898 	if (!(tu->timeri->flags & SNDRV_TIMER_IFLG_PAUSED))
1899 		return snd_timer_user_start(file);
1900 	tu->timeri->lost = 0;
1901 	return (err = snd_timer_continue(tu->timeri)) < 0 ? err : 0;
1902 }
1903 
1904 static int snd_timer_user_pause(struct file *file)
1905 {
1906 	int err;
1907 	struct snd_timer_user *tu;
1908 
1909 	tu = file->private_data;
1910 	if (!tu->timeri)
1911 		return -EBADFD;
1912 	return (err = snd_timer_pause(tu->timeri)) < 0 ? err : 0;
1913 }
1914 
1915 enum {
1916 	SNDRV_TIMER_IOCTL_START_OLD = _IO('T', 0x20),
1917 	SNDRV_TIMER_IOCTL_STOP_OLD = _IO('T', 0x21),
1918 	SNDRV_TIMER_IOCTL_CONTINUE_OLD = _IO('T', 0x22),
1919 	SNDRV_TIMER_IOCTL_PAUSE_OLD = _IO('T', 0x23),
1920 };
1921 
1922 static long __snd_timer_user_ioctl(struct file *file, unsigned int cmd,
1923 				 unsigned long arg)
1924 {
1925 	struct snd_timer_user *tu;
1926 	void __user *argp = (void __user *)arg;
1927 	int __user *p = argp;
1928 
1929 	tu = file->private_data;
1930 	switch (cmd) {
1931 	case SNDRV_TIMER_IOCTL_PVERSION:
1932 		return put_user(SNDRV_TIMER_VERSION, p) ? -EFAULT : 0;
1933 	case SNDRV_TIMER_IOCTL_NEXT_DEVICE:
1934 		return snd_timer_user_next_device(argp);
1935 	case SNDRV_TIMER_IOCTL_TREAD:
1936 	{
1937 		int xarg, old_tread;
1938 
1939 		if (tu->timeri)	/* too late */
1940 			return -EBUSY;
1941 		if (get_user(xarg, p))
1942 			return -EFAULT;
1943 		old_tread = tu->tread;
1944 		tu->tread = xarg ? 1 : 0;
1945 		if (tu->tread != old_tread &&
1946 		    realloc_user_queue(tu, tu->queue_size) < 0) {
1947 			tu->tread = old_tread;
1948 			return -ENOMEM;
1949 		}
1950 		return 0;
1951 	}
1952 	case SNDRV_TIMER_IOCTL_GINFO:
1953 		return snd_timer_user_ginfo(file, argp);
1954 	case SNDRV_TIMER_IOCTL_GPARAMS:
1955 		return snd_timer_user_gparams(file, argp);
1956 	case SNDRV_TIMER_IOCTL_GSTATUS:
1957 		return snd_timer_user_gstatus(file, argp);
1958 	case SNDRV_TIMER_IOCTL_SELECT:
1959 		return snd_timer_user_tselect(file, argp);
1960 	case SNDRV_TIMER_IOCTL_INFO:
1961 		return snd_timer_user_info(file, argp);
1962 	case SNDRV_TIMER_IOCTL_PARAMS:
1963 		return snd_timer_user_params(file, argp);
1964 	case SNDRV_TIMER_IOCTL_STATUS:
1965 		return snd_timer_user_status(file, argp);
1966 	case SNDRV_TIMER_IOCTL_START:
1967 	case SNDRV_TIMER_IOCTL_START_OLD:
1968 		return snd_timer_user_start(file);
1969 	case SNDRV_TIMER_IOCTL_STOP:
1970 	case SNDRV_TIMER_IOCTL_STOP_OLD:
1971 		return snd_timer_user_stop(file);
1972 	case SNDRV_TIMER_IOCTL_CONTINUE:
1973 	case SNDRV_TIMER_IOCTL_CONTINUE_OLD:
1974 		return snd_timer_user_continue(file);
1975 	case SNDRV_TIMER_IOCTL_PAUSE:
1976 	case SNDRV_TIMER_IOCTL_PAUSE_OLD:
1977 		return snd_timer_user_pause(file);
1978 	}
1979 	return -ENOTTY;
1980 }
1981 
1982 static long snd_timer_user_ioctl(struct file *file, unsigned int cmd,
1983 				 unsigned long arg)
1984 {
1985 	struct snd_timer_user *tu = file->private_data;
1986 	long ret;
1987 
1988 	mutex_lock(&tu->ioctl_lock);
1989 	ret = __snd_timer_user_ioctl(file, cmd, arg);
1990 	mutex_unlock(&tu->ioctl_lock);
1991 	return ret;
1992 }
1993 
1994 static int snd_timer_user_fasync(int fd, struct file * file, int on)
1995 {
1996 	struct snd_timer_user *tu;
1997 
1998 	tu = file->private_data;
1999 	return fasync_helper(fd, file, on, &tu->fasync);
2000 }
2001 
2002 static ssize_t snd_timer_user_read(struct file *file, char __user *buffer,
2003 				   size_t count, loff_t *offset)
2004 {
2005 	struct snd_timer_user *tu;
2006 	long result = 0, unit;
2007 	int qhead;
2008 	int err = 0;
2009 
2010 	tu = file->private_data;
2011 	unit = tu->tread ? sizeof(struct snd_timer_tread) : sizeof(struct snd_timer_read);
2012 	mutex_lock(&tu->ioctl_lock);
2013 	spin_lock_irq(&tu->qlock);
2014 	while ((long)count - result >= unit) {
2015 		while (!tu->qused) {
2016 			wait_queue_entry_t wait;
2017 
2018 			if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
2019 				err = -EAGAIN;
2020 				goto _error;
2021 			}
2022 
2023 			set_current_state(TASK_INTERRUPTIBLE);
2024 			init_waitqueue_entry(&wait, current);
2025 			add_wait_queue(&tu->qchange_sleep, &wait);
2026 
2027 			spin_unlock_irq(&tu->qlock);
2028 			mutex_unlock(&tu->ioctl_lock);
2029 			schedule();
2030 			mutex_lock(&tu->ioctl_lock);
2031 			spin_lock_irq(&tu->qlock);
2032 
2033 			remove_wait_queue(&tu->qchange_sleep, &wait);
2034 
2035 			if (tu->disconnected) {
2036 				err = -ENODEV;
2037 				goto _error;
2038 			}
2039 			if (signal_pending(current)) {
2040 				err = -ERESTARTSYS;
2041 				goto _error;
2042 			}
2043 		}
2044 
2045 		qhead = tu->qhead++;
2046 		tu->qhead %= tu->queue_size;
2047 		tu->qused--;
2048 		spin_unlock_irq(&tu->qlock);
2049 
2050 		if (tu->tread) {
2051 			if (copy_to_user(buffer, &tu->tqueue[qhead],
2052 					 sizeof(struct snd_timer_tread)))
2053 				err = -EFAULT;
2054 		} else {
2055 			if (copy_to_user(buffer, &tu->queue[qhead],
2056 					 sizeof(struct snd_timer_read)))
2057 				err = -EFAULT;
2058 		}
2059 
2060 		spin_lock_irq(&tu->qlock);
2061 		if (err < 0)
2062 			goto _error;
2063 		result += unit;
2064 		buffer += unit;
2065 	}
2066  _error:
2067 	spin_unlock_irq(&tu->qlock);
2068 	mutex_unlock(&tu->ioctl_lock);
2069 	return result > 0 ? result : err;
2070 }
2071 
2072 static unsigned int snd_timer_user_poll(struct file *file, poll_table * wait)
2073 {
2074         unsigned int mask;
2075         struct snd_timer_user *tu;
2076 
2077         tu = file->private_data;
2078 
2079         poll_wait(file, &tu->qchange_sleep, wait);
2080 
2081 	mask = 0;
2082 	spin_lock_irq(&tu->qlock);
2083 	if (tu->qused)
2084 		mask |= POLLIN | POLLRDNORM;
2085 	if (tu->disconnected)
2086 		mask |= POLLERR;
2087 	spin_unlock_irq(&tu->qlock);
2088 
2089 	return mask;
2090 }
2091 
2092 #ifdef CONFIG_COMPAT
2093 #include "timer_compat.c"
2094 #else
2095 #define snd_timer_user_ioctl_compat	NULL
2096 #endif
2097 
2098 static const struct file_operations snd_timer_f_ops =
2099 {
2100 	.owner =	THIS_MODULE,
2101 	.read =		snd_timer_user_read,
2102 	.open =		snd_timer_user_open,
2103 	.release =	snd_timer_user_release,
2104 	.llseek =	no_llseek,
2105 	.poll =		snd_timer_user_poll,
2106 	.unlocked_ioctl =	snd_timer_user_ioctl,
2107 	.compat_ioctl =	snd_timer_user_ioctl_compat,
2108 	.fasync = 	snd_timer_user_fasync,
2109 };
2110 
2111 /* unregister the system timer */
2112 static void snd_timer_free_all(void)
2113 {
2114 	struct snd_timer *timer, *n;
2115 
2116 	list_for_each_entry_safe(timer, n, &snd_timer_list, device_list)
2117 		snd_timer_free(timer);
2118 }
2119 
2120 static struct device timer_dev;
2121 
2122 /*
2123  *  ENTRY functions
2124  */
2125 
2126 static int __init alsa_timer_init(void)
2127 {
2128 	int err;
2129 
2130 	snd_device_initialize(&timer_dev, NULL);
2131 	dev_set_name(&timer_dev, "timer");
2132 
2133 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
2134 	snd_oss_info_register(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1,
2135 			      "system timer");
2136 #endif
2137 
2138 	err = snd_timer_register_system();
2139 	if (err < 0) {
2140 		pr_err("ALSA: unable to register system timer (%i)\n", err);
2141 		goto put_timer;
2142 	}
2143 
2144 	err = snd_register_device(SNDRV_DEVICE_TYPE_TIMER, NULL, 0,
2145 				  &snd_timer_f_ops, NULL, &timer_dev);
2146 	if (err < 0) {
2147 		pr_err("ALSA: unable to register timer device (%i)\n", err);
2148 		snd_timer_free_all();
2149 		goto put_timer;
2150 	}
2151 
2152 	snd_timer_proc_init();
2153 	return 0;
2154 
2155 put_timer:
2156 	put_device(&timer_dev);
2157 	return err;
2158 }
2159 
2160 static void __exit alsa_timer_exit(void)
2161 {
2162 	snd_unregister_device(&timer_dev);
2163 	snd_timer_free_all();
2164 	put_device(&timer_dev);
2165 	snd_timer_proc_done();
2166 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
2167 	snd_oss_info_unregister(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1);
2168 #endif
2169 }
2170 
2171 module_init(alsa_timer_init)
2172 module_exit(alsa_timer_exit)
2173