xref: /openbmc/linux/sound/core/timer.c (revision a17922de)
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 static unsigned long snd_timer_hw_resolution(struct snd_timer *timer)
431 {
432 	if (timer->hw.c_resolution)
433 		return timer->hw.c_resolution(timer);
434 	else
435 		return timer->hw.resolution;
436 }
437 
438 unsigned long snd_timer_resolution(struct snd_timer_instance *timeri)
439 {
440 	struct snd_timer * timer;
441 	unsigned long ret = 0;
442 	unsigned long flags;
443 
444 	if (timeri == NULL)
445 		return 0;
446 	timer = timeri->timer;
447 	if (timer) {
448 		spin_lock_irqsave(&timer->lock, flags);
449 		ret = snd_timer_hw_resolution(timer);
450 		spin_unlock_irqrestore(&timer->lock, flags);
451 	}
452 	return ret;
453 }
454 EXPORT_SYMBOL(snd_timer_resolution);
455 
456 static void snd_timer_notify1(struct snd_timer_instance *ti, int event)
457 {
458 	struct snd_timer *timer = ti->timer;
459 	unsigned long resolution = 0;
460 	struct snd_timer_instance *ts;
461 	struct timespec tstamp;
462 
463 	if (timer_tstamp_monotonic)
464 		ktime_get_ts(&tstamp);
465 	else
466 		getnstimeofday(&tstamp);
467 	if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_START ||
468 		       event > SNDRV_TIMER_EVENT_PAUSE))
469 		return;
470 	if (timer &&
471 	    (event == SNDRV_TIMER_EVENT_START ||
472 	     event == SNDRV_TIMER_EVENT_CONTINUE))
473 		resolution = snd_timer_hw_resolution(timer);
474 	if (ti->ccallback)
475 		ti->ccallback(ti, event, &tstamp, resolution);
476 	if (ti->flags & SNDRV_TIMER_IFLG_SLAVE)
477 		return;
478 	if (timer == NULL)
479 		return;
480 	if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
481 		return;
482 	list_for_each_entry(ts, &ti->slave_active_head, active_list)
483 		if (ts->ccallback)
484 			ts->ccallback(ts, event + 100, &tstamp, resolution);
485 }
486 
487 /* start/continue a master timer */
488 static int snd_timer_start1(struct snd_timer_instance *timeri,
489 			    bool start, unsigned long ticks)
490 {
491 	struct snd_timer *timer;
492 	int result;
493 	unsigned long flags;
494 
495 	timer = timeri->timer;
496 	if (!timer)
497 		return -EINVAL;
498 
499 	spin_lock_irqsave(&timer->lock, flags);
500 	if (timer->card && timer->card->shutdown) {
501 		result = -ENODEV;
502 		goto unlock;
503 	}
504 	if (timeri->flags & (SNDRV_TIMER_IFLG_RUNNING |
505 			     SNDRV_TIMER_IFLG_START)) {
506 		result = -EBUSY;
507 		goto unlock;
508 	}
509 
510 	if (start)
511 		timeri->ticks = timeri->cticks = ticks;
512 	else if (!timeri->cticks)
513 		timeri->cticks = 1;
514 	timeri->pticks = 0;
515 
516 	list_move_tail(&timeri->active_list, &timer->active_list_head);
517 	if (timer->running) {
518 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
519 			goto __start_now;
520 		timer->flags |= SNDRV_TIMER_FLG_RESCHED;
521 		timeri->flags |= SNDRV_TIMER_IFLG_START;
522 		result = 1; /* delayed start */
523 	} else {
524 		if (start)
525 			timer->sticks = ticks;
526 		timer->hw.start(timer);
527 	      __start_now:
528 		timer->running++;
529 		timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
530 		result = 0;
531 	}
532 	snd_timer_notify1(timeri, start ? SNDRV_TIMER_EVENT_START :
533 			  SNDRV_TIMER_EVENT_CONTINUE);
534  unlock:
535 	spin_unlock_irqrestore(&timer->lock, flags);
536 	return result;
537 }
538 
539 /* start/continue a slave timer */
540 static int snd_timer_start_slave(struct snd_timer_instance *timeri,
541 				 bool start)
542 {
543 	unsigned long flags;
544 
545 	spin_lock_irqsave(&slave_active_lock, flags);
546 	if (timeri->flags & SNDRV_TIMER_IFLG_RUNNING) {
547 		spin_unlock_irqrestore(&slave_active_lock, flags);
548 		return -EBUSY;
549 	}
550 	timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
551 	if (timeri->master && timeri->timer) {
552 		spin_lock(&timeri->timer->lock);
553 		list_add_tail(&timeri->active_list,
554 			      &timeri->master->slave_active_head);
555 		snd_timer_notify1(timeri, start ? SNDRV_TIMER_EVENT_START :
556 				  SNDRV_TIMER_EVENT_CONTINUE);
557 		spin_unlock(&timeri->timer->lock);
558 	}
559 	spin_unlock_irqrestore(&slave_active_lock, flags);
560 	return 1; /* delayed start */
561 }
562 
563 /* stop/pause a master timer */
564 static int snd_timer_stop1(struct snd_timer_instance *timeri, bool stop)
565 {
566 	struct snd_timer *timer;
567 	int result = 0;
568 	unsigned long flags;
569 
570 	timer = timeri->timer;
571 	if (!timer)
572 		return -EINVAL;
573 	spin_lock_irqsave(&timer->lock, flags);
574 	if (!(timeri->flags & (SNDRV_TIMER_IFLG_RUNNING |
575 			       SNDRV_TIMER_IFLG_START))) {
576 		result = -EBUSY;
577 		goto unlock;
578 	}
579 	list_del_init(&timeri->ack_list);
580 	list_del_init(&timeri->active_list);
581 	if (timer->card && timer->card->shutdown)
582 		goto unlock;
583 	if (stop) {
584 		timeri->cticks = timeri->ticks;
585 		timeri->pticks = 0;
586 	}
587 	if ((timeri->flags & SNDRV_TIMER_IFLG_RUNNING) &&
588 	    !(--timer->running)) {
589 		timer->hw.stop(timer);
590 		if (timer->flags & SNDRV_TIMER_FLG_RESCHED) {
591 			timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
592 			snd_timer_reschedule(timer, 0);
593 			if (timer->flags & SNDRV_TIMER_FLG_CHANGE) {
594 				timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
595 				timer->hw.start(timer);
596 			}
597 		}
598 	}
599 	timeri->flags &= ~(SNDRV_TIMER_IFLG_RUNNING | SNDRV_TIMER_IFLG_START);
600 	if (stop)
601 		timeri->flags &= ~SNDRV_TIMER_IFLG_PAUSED;
602 	else
603 		timeri->flags |= SNDRV_TIMER_IFLG_PAUSED;
604 	snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :
605 			  SNDRV_TIMER_EVENT_PAUSE);
606  unlock:
607 	spin_unlock_irqrestore(&timer->lock, flags);
608 	return result;
609 }
610 
611 /* stop/pause a slave timer */
612 static int snd_timer_stop_slave(struct snd_timer_instance *timeri, bool stop)
613 {
614 	unsigned long flags;
615 
616 	spin_lock_irqsave(&slave_active_lock, flags);
617 	if (!(timeri->flags & SNDRV_TIMER_IFLG_RUNNING)) {
618 		spin_unlock_irqrestore(&slave_active_lock, flags);
619 		return -EBUSY;
620 	}
621 	timeri->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
622 	if (timeri->timer) {
623 		spin_lock(&timeri->timer->lock);
624 		list_del_init(&timeri->ack_list);
625 		list_del_init(&timeri->active_list);
626 		snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :
627 				  SNDRV_TIMER_EVENT_PAUSE);
628 		spin_unlock(&timeri->timer->lock);
629 	}
630 	spin_unlock_irqrestore(&slave_active_lock, flags);
631 	return 0;
632 }
633 
634 /*
635  *  start the timer instance
636  */
637 int snd_timer_start(struct snd_timer_instance *timeri, unsigned int ticks)
638 {
639 	if (timeri == NULL || ticks < 1)
640 		return -EINVAL;
641 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
642 		return snd_timer_start_slave(timeri, true);
643 	else
644 		return snd_timer_start1(timeri, true, ticks);
645 }
646 EXPORT_SYMBOL(snd_timer_start);
647 
648 /*
649  * stop the timer instance.
650  *
651  * do not call this from the timer callback!
652  */
653 int snd_timer_stop(struct snd_timer_instance *timeri)
654 {
655 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
656 		return snd_timer_stop_slave(timeri, true);
657 	else
658 		return snd_timer_stop1(timeri, true);
659 }
660 EXPORT_SYMBOL(snd_timer_stop);
661 
662 /*
663  * start again..  the tick is kept.
664  */
665 int snd_timer_continue(struct snd_timer_instance *timeri)
666 {
667 	/* timer can continue only after pause */
668 	if (!(timeri->flags & SNDRV_TIMER_IFLG_PAUSED))
669 		return -EINVAL;
670 
671 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
672 		return snd_timer_start_slave(timeri, false);
673 	else
674 		return snd_timer_start1(timeri, false, 0);
675 }
676 EXPORT_SYMBOL(snd_timer_continue);
677 
678 /*
679  * pause.. remember the ticks left
680  */
681 int snd_timer_pause(struct snd_timer_instance * timeri)
682 {
683 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
684 		return snd_timer_stop_slave(timeri, false);
685 	else
686 		return snd_timer_stop1(timeri, false);
687 }
688 EXPORT_SYMBOL(snd_timer_pause);
689 
690 /*
691  * reschedule the timer
692  *
693  * start pending instances and check the scheduling ticks.
694  * when the scheduling ticks is changed set CHANGE flag to reprogram the timer.
695  */
696 static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left)
697 {
698 	struct snd_timer_instance *ti;
699 	unsigned long ticks = ~0UL;
700 
701 	list_for_each_entry(ti, &timer->active_list_head, active_list) {
702 		if (ti->flags & SNDRV_TIMER_IFLG_START) {
703 			ti->flags &= ~SNDRV_TIMER_IFLG_START;
704 			ti->flags |= SNDRV_TIMER_IFLG_RUNNING;
705 			timer->running++;
706 		}
707 		if (ti->flags & SNDRV_TIMER_IFLG_RUNNING) {
708 			if (ticks > ti->cticks)
709 				ticks = ti->cticks;
710 		}
711 	}
712 	if (ticks == ~0UL) {
713 		timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
714 		return;
715 	}
716 	if (ticks > timer->hw.ticks)
717 		ticks = timer->hw.ticks;
718 	if (ticks_left != ticks)
719 		timer->flags |= SNDRV_TIMER_FLG_CHANGE;
720 	timer->sticks = ticks;
721 }
722 
723 /*
724  * timer tasklet
725  *
726  */
727 static void snd_timer_tasklet(unsigned long arg)
728 {
729 	struct snd_timer *timer = (struct snd_timer *) arg;
730 	struct snd_timer_instance *ti;
731 	struct list_head *p;
732 	unsigned long resolution, ticks;
733 	unsigned long flags;
734 
735 	if (timer->card && timer->card->shutdown)
736 		return;
737 
738 	spin_lock_irqsave(&timer->lock, flags);
739 	/* now process all callbacks */
740 	while (!list_empty(&timer->sack_list_head)) {
741 		p = timer->sack_list_head.next;		/* get first item */
742 		ti = list_entry(p, struct snd_timer_instance, ack_list);
743 
744 		/* remove from ack_list and make empty */
745 		list_del_init(p);
746 
747 		ticks = ti->pticks;
748 		ti->pticks = 0;
749 		resolution = ti->resolution;
750 
751 		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
752 		spin_unlock(&timer->lock);
753 		if (ti->callback)
754 			ti->callback(ti, resolution, ticks);
755 		spin_lock(&timer->lock);
756 		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
757 	}
758 	spin_unlock_irqrestore(&timer->lock, flags);
759 }
760 
761 /*
762  * timer interrupt
763  *
764  * ticks_left is usually equal to timer->sticks.
765  *
766  */
767 void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
768 {
769 	struct snd_timer_instance *ti, *ts, *tmp;
770 	unsigned long resolution, ticks;
771 	struct list_head *p, *ack_list_head;
772 	unsigned long flags;
773 	int use_tasklet = 0;
774 
775 	if (timer == NULL)
776 		return;
777 
778 	if (timer->card && timer->card->shutdown)
779 		return;
780 
781 	spin_lock_irqsave(&timer->lock, flags);
782 
783 	/* remember the current resolution */
784 	resolution = snd_timer_hw_resolution(timer);
785 
786 	/* loop for all active instances
787 	 * Here we cannot use list_for_each_entry because the active_list of a
788 	 * processed instance is relinked to done_list_head before the callback
789 	 * is called.
790 	 */
791 	list_for_each_entry_safe(ti, tmp, &timer->active_list_head,
792 				 active_list) {
793 		if (!(ti->flags & SNDRV_TIMER_IFLG_RUNNING))
794 			continue;
795 		ti->pticks += ticks_left;
796 		ti->resolution = resolution;
797 		if (ti->cticks < ticks_left)
798 			ti->cticks = 0;
799 		else
800 			ti->cticks -= ticks_left;
801 		if (ti->cticks) /* not expired */
802 			continue;
803 		if (ti->flags & SNDRV_TIMER_IFLG_AUTO) {
804 			ti->cticks = ti->ticks;
805 		} else {
806 			ti->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
807 			--timer->running;
808 			list_del_init(&ti->active_list);
809 		}
810 		if ((timer->hw.flags & SNDRV_TIMER_HW_TASKLET) ||
811 		    (ti->flags & SNDRV_TIMER_IFLG_FAST))
812 			ack_list_head = &timer->ack_list_head;
813 		else
814 			ack_list_head = &timer->sack_list_head;
815 		if (list_empty(&ti->ack_list))
816 			list_add_tail(&ti->ack_list, ack_list_head);
817 		list_for_each_entry(ts, &ti->slave_active_head, active_list) {
818 			ts->pticks = ti->pticks;
819 			ts->resolution = resolution;
820 			if (list_empty(&ts->ack_list))
821 				list_add_tail(&ts->ack_list, ack_list_head);
822 		}
823 	}
824 	if (timer->flags & SNDRV_TIMER_FLG_RESCHED)
825 		snd_timer_reschedule(timer, timer->sticks);
826 	if (timer->running) {
827 		if (timer->hw.flags & SNDRV_TIMER_HW_STOP) {
828 			timer->hw.stop(timer);
829 			timer->flags |= SNDRV_TIMER_FLG_CHANGE;
830 		}
831 		if (!(timer->hw.flags & SNDRV_TIMER_HW_AUTO) ||
832 		    (timer->flags & SNDRV_TIMER_FLG_CHANGE)) {
833 			/* restart timer */
834 			timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
835 			timer->hw.start(timer);
836 		}
837 	} else {
838 		timer->hw.stop(timer);
839 	}
840 
841 	/* now process all fast callbacks */
842 	while (!list_empty(&timer->ack_list_head)) {
843 		p = timer->ack_list_head.next;		/* get first item */
844 		ti = list_entry(p, struct snd_timer_instance, ack_list);
845 
846 		/* remove from ack_list and make empty */
847 		list_del_init(p);
848 
849 		ticks = ti->pticks;
850 		ti->pticks = 0;
851 
852 		ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
853 		spin_unlock(&timer->lock);
854 		if (ti->callback)
855 			ti->callback(ti, resolution, ticks);
856 		spin_lock(&timer->lock);
857 		ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
858 	}
859 
860 	/* do we have any slow callbacks? */
861 	use_tasklet = !list_empty(&timer->sack_list_head);
862 	spin_unlock_irqrestore(&timer->lock, flags);
863 
864 	if (use_tasklet)
865 		tasklet_schedule(&timer->task_queue);
866 }
867 EXPORT_SYMBOL(snd_timer_interrupt);
868 
869 /*
870 
871  */
872 
873 int snd_timer_new(struct snd_card *card, char *id, struct snd_timer_id *tid,
874 		  struct snd_timer **rtimer)
875 {
876 	struct snd_timer *timer;
877 	int err;
878 	static struct snd_device_ops ops = {
879 		.dev_free = snd_timer_dev_free,
880 		.dev_register = snd_timer_dev_register,
881 		.dev_disconnect = snd_timer_dev_disconnect,
882 	};
883 
884 	if (snd_BUG_ON(!tid))
885 		return -EINVAL;
886 	if (rtimer)
887 		*rtimer = NULL;
888 	timer = kzalloc(sizeof(*timer), GFP_KERNEL);
889 	if (!timer)
890 		return -ENOMEM;
891 	timer->tmr_class = tid->dev_class;
892 	timer->card = card;
893 	timer->tmr_device = tid->device;
894 	timer->tmr_subdevice = tid->subdevice;
895 	if (id)
896 		strlcpy(timer->id, id, sizeof(timer->id));
897 	timer->sticks = 1;
898 	INIT_LIST_HEAD(&timer->device_list);
899 	INIT_LIST_HEAD(&timer->open_list_head);
900 	INIT_LIST_HEAD(&timer->active_list_head);
901 	INIT_LIST_HEAD(&timer->ack_list_head);
902 	INIT_LIST_HEAD(&timer->sack_list_head);
903 	spin_lock_init(&timer->lock);
904 	tasklet_init(&timer->task_queue, snd_timer_tasklet,
905 		     (unsigned long)timer);
906 	timer->max_instances = 1000; /* default limit per timer */
907 	if (card != NULL) {
908 		timer->module = card->module;
909 		err = snd_device_new(card, SNDRV_DEV_TIMER, timer, &ops);
910 		if (err < 0) {
911 			snd_timer_free(timer);
912 			return err;
913 		}
914 	}
915 	if (rtimer)
916 		*rtimer = timer;
917 	return 0;
918 }
919 EXPORT_SYMBOL(snd_timer_new);
920 
921 static int snd_timer_free(struct snd_timer *timer)
922 {
923 	if (!timer)
924 		return 0;
925 
926 	mutex_lock(&register_mutex);
927 	if (! list_empty(&timer->open_list_head)) {
928 		struct list_head *p, *n;
929 		struct snd_timer_instance *ti;
930 		pr_warn("ALSA: timer %p is busy?\n", timer);
931 		list_for_each_safe(p, n, &timer->open_list_head) {
932 			list_del_init(p);
933 			ti = list_entry(p, struct snd_timer_instance, open_list);
934 			ti->timer = NULL;
935 		}
936 	}
937 	list_del(&timer->device_list);
938 	mutex_unlock(&register_mutex);
939 
940 	if (timer->private_free)
941 		timer->private_free(timer);
942 	kfree(timer);
943 	return 0;
944 }
945 
946 static int snd_timer_dev_free(struct snd_device *device)
947 {
948 	struct snd_timer *timer = device->device_data;
949 	return snd_timer_free(timer);
950 }
951 
952 static int snd_timer_dev_register(struct snd_device *dev)
953 {
954 	struct snd_timer *timer = dev->device_data;
955 	struct snd_timer *timer1;
956 
957 	if (snd_BUG_ON(!timer || !timer->hw.start || !timer->hw.stop))
958 		return -ENXIO;
959 	if (!(timer->hw.flags & SNDRV_TIMER_HW_SLAVE) &&
960 	    !timer->hw.resolution && timer->hw.c_resolution == NULL)
961 	    	return -EINVAL;
962 
963 	mutex_lock(&register_mutex);
964 	list_for_each_entry(timer1, &snd_timer_list, device_list) {
965 		if (timer1->tmr_class > timer->tmr_class)
966 			break;
967 		if (timer1->tmr_class < timer->tmr_class)
968 			continue;
969 		if (timer1->card && timer->card) {
970 			if (timer1->card->number > timer->card->number)
971 				break;
972 			if (timer1->card->number < timer->card->number)
973 				continue;
974 		}
975 		if (timer1->tmr_device > timer->tmr_device)
976 			break;
977 		if (timer1->tmr_device < timer->tmr_device)
978 			continue;
979 		if (timer1->tmr_subdevice > timer->tmr_subdevice)
980 			break;
981 		if (timer1->tmr_subdevice < timer->tmr_subdevice)
982 			continue;
983 		/* conflicts.. */
984 		mutex_unlock(&register_mutex);
985 		return -EBUSY;
986 	}
987 	list_add_tail(&timer->device_list, &timer1->device_list);
988 	mutex_unlock(&register_mutex);
989 	return 0;
990 }
991 
992 static int snd_timer_dev_disconnect(struct snd_device *device)
993 {
994 	struct snd_timer *timer = device->device_data;
995 	struct snd_timer_instance *ti;
996 
997 	mutex_lock(&register_mutex);
998 	list_del_init(&timer->device_list);
999 	/* wake up pending sleepers */
1000 	list_for_each_entry(ti, &timer->open_list_head, open_list) {
1001 		if (ti->disconnect)
1002 			ti->disconnect(ti);
1003 	}
1004 	mutex_unlock(&register_mutex);
1005 	return 0;
1006 }
1007 
1008 void snd_timer_notify(struct snd_timer *timer, int event, struct timespec *tstamp)
1009 {
1010 	unsigned long flags;
1011 	unsigned long resolution = 0;
1012 	struct snd_timer_instance *ti, *ts;
1013 
1014 	if (timer->card && timer->card->shutdown)
1015 		return;
1016 	if (! (timer->hw.flags & SNDRV_TIMER_HW_SLAVE))
1017 		return;
1018 	if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_MSTART ||
1019 		       event > SNDRV_TIMER_EVENT_MRESUME))
1020 		return;
1021 	spin_lock_irqsave(&timer->lock, flags);
1022 	if (event == SNDRV_TIMER_EVENT_MSTART ||
1023 	    event == SNDRV_TIMER_EVENT_MCONTINUE ||
1024 	    event == SNDRV_TIMER_EVENT_MRESUME)
1025 		resolution = snd_timer_hw_resolution(timer);
1026 	list_for_each_entry(ti, &timer->active_list_head, active_list) {
1027 		if (ti->ccallback)
1028 			ti->ccallback(ti, event, tstamp, resolution);
1029 		list_for_each_entry(ts, &ti->slave_active_head, active_list)
1030 			if (ts->ccallback)
1031 				ts->ccallback(ts, event, tstamp, resolution);
1032 	}
1033 	spin_unlock_irqrestore(&timer->lock, flags);
1034 }
1035 EXPORT_SYMBOL(snd_timer_notify);
1036 
1037 /*
1038  * exported functions for global timers
1039  */
1040 int snd_timer_global_new(char *id, int device, struct snd_timer **rtimer)
1041 {
1042 	struct snd_timer_id tid;
1043 
1044 	tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
1045 	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1046 	tid.card = -1;
1047 	tid.device = device;
1048 	tid.subdevice = 0;
1049 	return snd_timer_new(NULL, id, &tid, rtimer);
1050 }
1051 EXPORT_SYMBOL(snd_timer_global_new);
1052 
1053 int snd_timer_global_free(struct snd_timer *timer)
1054 {
1055 	return snd_timer_free(timer);
1056 }
1057 EXPORT_SYMBOL(snd_timer_global_free);
1058 
1059 int snd_timer_global_register(struct snd_timer *timer)
1060 {
1061 	struct snd_device dev;
1062 
1063 	memset(&dev, 0, sizeof(dev));
1064 	dev.device_data = timer;
1065 	return snd_timer_dev_register(&dev);
1066 }
1067 EXPORT_SYMBOL(snd_timer_global_register);
1068 
1069 /*
1070  *  System timer
1071  */
1072 
1073 struct snd_timer_system_private {
1074 	struct timer_list tlist;
1075 	struct snd_timer *snd_timer;
1076 	unsigned long last_expires;
1077 	unsigned long last_jiffies;
1078 	unsigned long correction;
1079 };
1080 
1081 static void snd_timer_s_function(struct timer_list *t)
1082 {
1083 	struct snd_timer_system_private *priv = from_timer(priv, t,
1084 								tlist);
1085 	struct snd_timer *timer = priv->snd_timer;
1086 	unsigned long jiff = jiffies;
1087 	if (time_after(jiff, priv->last_expires))
1088 		priv->correction += (long)jiff - (long)priv->last_expires;
1089 	snd_timer_interrupt(timer, (long)jiff - (long)priv->last_jiffies);
1090 }
1091 
1092 static int snd_timer_s_start(struct snd_timer * timer)
1093 {
1094 	struct snd_timer_system_private *priv;
1095 	unsigned long njiff;
1096 
1097 	priv = (struct snd_timer_system_private *) timer->private_data;
1098 	njiff = (priv->last_jiffies = jiffies);
1099 	if (priv->correction > timer->sticks - 1) {
1100 		priv->correction -= timer->sticks - 1;
1101 		njiff++;
1102 	} else {
1103 		njiff += timer->sticks - priv->correction;
1104 		priv->correction = 0;
1105 	}
1106 	priv->last_expires = njiff;
1107 	mod_timer(&priv->tlist, njiff);
1108 	return 0;
1109 }
1110 
1111 static int snd_timer_s_stop(struct snd_timer * timer)
1112 {
1113 	struct snd_timer_system_private *priv;
1114 	unsigned long jiff;
1115 
1116 	priv = (struct snd_timer_system_private *) timer->private_data;
1117 	del_timer(&priv->tlist);
1118 	jiff = jiffies;
1119 	if (time_before(jiff, priv->last_expires))
1120 		timer->sticks = priv->last_expires - jiff;
1121 	else
1122 		timer->sticks = 1;
1123 	priv->correction = 0;
1124 	return 0;
1125 }
1126 
1127 static int snd_timer_s_close(struct snd_timer *timer)
1128 {
1129 	struct snd_timer_system_private *priv;
1130 
1131 	priv = (struct snd_timer_system_private *)timer->private_data;
1132 	del_timer_sync(&priv->tlist);
1133 	return 0;
1134 }
1135 
1136 static struct snd_timer_hardware snd_timer_system =
1137 {
1138 	.flags =	SNDRV_TIMER_HW_FIRST | SNDRV_TIMER_HW_TASKLET,
1139 	.resolution =	1000000000L / HZ,
1140 	.ticks =	10000000L,
1141 	.close =	snd_timer_s_close,
1142 	.start =	snd_timer_s_start,
1143 	.stop =		snd_timer_s_stop
1144 };
1145 
1146 static void snd_timer_free_system(struct snd_timer *timer)
1147 {
1148 	kfree(timer->private_data);
1149 }
1150 
1151 static int snd_timer_register_system(void)
1152 {
1153 	struct snd_timer *timer;
1154 	struct snd_timer_system_private *priv;
1155 	int err;
1156 
1157 	err = snd_timer_global_new("system", SNDRV_TIMER_GLOBAL_SYSTEM, &timer);
1158 	if (err < 0)
1159 		return err;
1160 	strcpy(timer->name, "system timer");
1161 	timer->hw = snd_timer_system;
1162 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1163 	if (priv == NULL) {
1164 		snd_timer_free(timer);
1165 		return -ENOMEM;
1166 	}
1167 	priv->snd_timer = timer;
1168 	timer_setup(&priv->tlist, snd_timer_s_function, 0);
1169 	timer->private_data = priv;
1170 	timer->private_free = snd_timer_free_system;
1171 	return snd_timer_global_register(timer);
1172 }
1173 
1174 #ifdef CONFIG_SND_PROC_FS
1175 /*
1176  *  Info interface
1177  */
1178 
1179 static void snd_timer_proc_read(struct snd_info_entry *entry,
1180 				struct snd_info_buffer *buffer)
1181 {
1182 	struct snd_timer *timer;
1183 	struct snd_timer_instance *ti;
1184 
1185 	mutex_lock(&register_mutex);
1186 	list_for_each_entry(timer, &snd_timer_list, device_list) {
1187 		if (timer->card && timer->card->shutdown)
1188 			continue;
1189 		switch (timer->tmr_class) {
1190 		case SNDRV_TIMER_CLASS_GLOBAL:
1191 			snd_iprintf(buffer, "G%i: ", timer->tmr_device);
1192 			break;
1193 		case SNDRV_TIMER_CLASS_CARD:
1194 			snd_iprintf(buffer, "C%i-%i: ",
1195 				    timer->card->number, timer->tmr_device);
1196 			break;
1197 		case SNDRV_TIMER_CLASS_PCM:
1198 			snd_iprintf(buffer, "P%i-%i-%i: ", timer->card->number,
1199 				    timer->tmr_device, timer->tmr_subdevice);
1200 			break;
1201 		default:
1202 			snd_iprintf(buffer, "?%i-%i-%i-%i: ", timer->tmr_class,
1203 				    timer->card ? timer->card->number : -1,
1204 				    timer->tmr_device, timer->tmr_subdevice);
1205 		}
1206 		snd_iprintf(buffer, "%s :", timer->name);
1207 		if (timer->hw.resolution)
1208 			snd_iprintf(buffer, " %lu.%03luus (%lu ticks)",
1209 				    timer->hw.resolution / 1000,
1210 				    timer->hw.resolution % 1000,
1211 				    timer->hw.ticks);
1212 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
1213 			snd_iprintf(buffer, " SLAVE");
1214 		snd_iprintf(buffer, "\n");
1215 		list_for_each_entry(ti, &timer->open_list_head, open_list)
1216 			snd_iprintf(buffer, "  Client %s : %s\n",
1217 				    ti->owner ? ti->owner : "unknown",
1218 				    ti->flags & (SNDRV_TIMER_IFLG_START |
1219 						 SNDRV_TIMER_IFLG_RUNNING)
1220 				    ? "running" : "stopped");
1221 	}
1222 	mutex_unlock(&register_mutex);
1223 }
1224 
1225 static struct snd_info_entry *snd_timer_proc_entry;
1226 
1227 static void __init snd_timer_proc_init(void)
1228 {
1229 	struct snd_info_entry *entry;
1230 
1231 	entry = snd_info_create_module_entry(THIS_MODULE, "timers", NULL);
1232 	if (entry != NULL) {
1233 		entry->c.text.read = snd_timer_proc_read;
1234 		if (snd_info_register(entry) < 0) {
1235 			snd_info_free_entry(entry);
1236 			entry = NULL;
1237 		}
1238 	}
1239 	snd_timer_proc_entry = entry;
1240 }
1241 
1242 static void __exit snd_timer_proc_done(void)
1243 {
1244 	snd_info_free_entry(snd_timer_proc_entry);
1245 }
1246 #else /* !CONFIG_SND_PROC_FS */
1247 #define snd_timer_proc_init()
1248 #define snd_timer_proc_done()
1249 #endif
1250 
1251 /*
1252  *  USER SPACE interface
1253  */
1254 
1255 static void snd_timer_user_interrupt(struct snd_timer_instance *timeri,
1256 				     unsigned long resolution,
1257 				     unsigned long ticks)
1258 {
1259 	struct snd_timer_user *tu = timeri->callback_data;
1260 	struct snd_timer_read *r;
1261 	int prev;
1262 
1263 	spin_lock(&tu->qlock);
1264 	if (tu->qused > 0) {
1265 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1266 		r = &tu->queue[prev];
1267 		if (r->resolution == resolution) {
1268 			r->ticks += ticks;
1269 			goto __wake;
1270 		}
1271 	}
1272 	if (tu->qused >= tu->queue_size) {
1273 		tu->overrun++;
1274 	} else {
1275 		r = &tu->queue[tu->qtail++];
1276 		tu->qtail %= tu->queue_size;
1277 		r->resolution = resolution;
1278 		r->ticks = ticks;
1279 		tu->qused++;
1280 	}
1281       __wake:
1282 	spin_unlock(&tu->qlock);
1283 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1284 	wake_up(&tu->qchange_sleep);
1285 }
1286 
1287 static void snd_timer_user_append_to_tqueue(struct snd_timer_user *tu,
1288 					    struct snd_timer_tread *tread)
1289 {
1290 	if (tu->qused >= tu->queue_size) {
1291 		tu->overrun++;
1292 	} else {
1293 		memcpy(&tu->tqueue[tu->qtail++], tread, sizeof(*tread));
1294 		tu->qtail %= tu->queue_size;
1295 		tu->qused++;
1296 	}
1297 }
1298 
1299 static void snd_timer_user_ccallback(struct snd_timer_instance *timeri,
1300 				     int event,
1301 				     struct timespec *tstamp,
1302 				     unsigned long resolution)
1303 {
1304 	struct snd_timer_user *tu = timeri->callback_data;
1305 	struct snd_timer_tread r1;
1306 	unsigned long flags;
1307 
1308 	if (event >= SNDRV_TIMER_EVENT_START &&
1309 	    event <= SNDRV_TIMER_EVENT_PAUSE)
1310 		tu->tstamp = *tstamp;
1311 	if ((tu->filter & (1 << event)) == 0 || !tu->tread)
1312 		return;
1313 	memset(&r1, 0, sizeof(r1));
1314 	r1.event = event;
1315 	r1.tstamp = *tstamp;
1316 	r1.val = resolution;
1317 	spin_lock_irqsave(&tu->qlock, flags);
1318 	snd_timer_user_append_to_tqueue(tu, &r1);
1319 	spin_unlock_irqrestore(&tu->qlock, flags);
1320 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1321 	wake_up(&tu->qchange_sleep);
1322 }
1323 
1324 static void snd_timer_user_disconnect(struct snd_timer_instance *timeri)
1325 {
1326 	struct snd_timer_user *tu = timeri->callback_data;
1327 
1328 	tu->disconnected = true;
1329 	wake_up(&tu->qchange_sleep);
1330 }
1331 
1332 static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
1333 				      unsigned long resolution,
1334 				      unsigned long ticks)
1335 {
1336 	struct snd_timer_user *tu = timeri->callback_data;
1337 	struct snd_timer_tread *r, r1;
1338 	struct timespec tstamp;
1339 	int prev, append = 0;
1340 
1341 	memset(&r1, 0, sizeof(r1));
1342 	memset(&tstamp, 0, sizeof(tstamp));
1343 	spin_lock(&tu->qlock);
1344 	if ((tu->filter & ((1 << SNDRV_TIMER_EVENT_RESOLUTION) |
1345 			   (1 << SNDRV_TIMER_EVENT_TICK))) == 0) {
1346 		spin_unlock(&tu->qlock);
1347 		return;
1348 	}
1349 	if (tu->last_resolution != resolution || ticks > 0) {
1350 		if (timer_tstamp_monotonic)
1351 			ktime_get_ts(&tstamp);
1352 		else
1353 			getnstimeofday(&tstamp);
1354 	}
1355 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_RESOLUTION)) &&
1356 	    tu->last_resolution != resolution) {
1357 		r1.event = SNDRV_TIMER_EVENT_RESOLUTION;
1358 		r1.tstamp = tstamp;
1359 		r1.val = resolution;
1360 		snd_timer_user_append_to_tqueue(tu, &r1);
1361 		tu->last_resolution = resolution;
1362 		append++;
1363 	}
1364 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_TICK)) == 0)
1365 		goto __wake;
1366 	if (ticks == 0)
1367 		goto __wake;
1368 	if (tu->qused > 0) {
1369 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1370 		r = &tu->tqueue[prev];
1371 		if (r->event == SNDRV_TIMER_EVENT_TICK) {
1372 			r->tstamp = tstamp;
1373 			r->val += ticks;
1374 			append++;
1375 			goto __wake;
1376 		}
1377 	}
1378 	r1.event = SNDRV_TIMER_EVENT_TICK;
1379 	r1.tstamp = tstamp;
1380 	r1.val = ticks;
1381 	snd_timer_user_append_to_tqueue(tu, &r1);
1382 	append++;
1383       __wake:
1384 	spin_unlock(&tu->qlock);
1385 	if (append == 0)
1386 		return;
1387 	kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1388 	wake_up(&tu->qchange_sleep);
1389 }
1390 
1391 static int realloc_user_queue(struct snd_timer_user *tu, int size)
1392 {
1393 	struct snd_timer_read *queue = NULL;
1394 	struct snd_timer_tread *tqueue = NULL;
1395 
1396 	if (tu->tread) {
1397 		tqueue = kcalloc(size, sizeof(*tqueue), GFP_KERNEL);
1398 		if (!tqueue)
1399 			return -ENOMEM;
1400 	} else {
1401 		queue = kcalloc(size, sizeof(*queue), GFP_KERNEL);
1402 		if (!queue)
1403 			return -ENOMEM;
1404 	}
1405 
1406 	spin_lock_irq(&tu->qlock);
1407 	kfree(tu->queue);
1408 	kfree(tu->tqueue);
1409 	tu->queue_size = size;
1410 	tu->queue = queue;
1411 	tu->tqueue = tqueue;
1412 	tu->qhead = tu->qtail = tu->qused = 0;
1413 	spin_unlock_irq(&tu->qlock);
1414 
1415 	return 0;
1416 }
1417 
1418 static int snd_timer_user_open(struct inode *inode, struct file *file)
1419 {
1420 	struct snd_timer_user *tu;
1421 	int err;
1422 
1423 	err = nonseekable_open(inode, file);
1424 	if (err < 0)
1425 		return err;
1426 
1427 	tu = kzalloc(sizeof(*tu), GFP_KERNEL);
1428 	if (tu == NULL)
1429 		return -ENOMEM;
1430 	spin_lock_init(&tu->qlock);
1431 	init_waitqueue_head(&tu->qchange_sleep);
1432 	mutex_init(&tu->ioctl_lock);
1433 	tu->ticks = 1;
1434 	if (realloc_user_queue(tu, 128) < 0) {
1435 		kfree(tu);
1436 		return -ENOMEM;
1437 	}
1438 	file->private_data = tu;
1439 	return 0;
1440 }
1441 
1442 static int snd_timer_user_release(struct inode *inode, struct file *file)
1443 {
1444 	struct snd_timer_user *tu;
1445 
1446 	if (file->private_data) {
1447 		tu = file->private_data;
1448 		file->private_data = NULL;
1449 		mutex_lock(&tu->ioctl_lock);
1450 		if (tu->timeri)
1451 			snd_timer_close(tu->timeri);
1452 		mutex_unlock(&tu->ioctl_lock);
1453 		kfree(tu->queue);
1454 		kfree(tu->tqueue);
1455 		kfree(tu);
1456 	}
1457 	return 0;
1458 }
1459 
1460 static void snd_timer_user_zero_id(struct snd_timer_id *id)
1461 {
1462 	id->dev_class = SNDRV_TIMER_CLASS_NONE;
1463 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1464 	id->card = -1;
1465 	id->device = -1;
1466 	id->subdevice = -1;
1467 }
1468 
1469 static void snd_timer_user_copy_id(struct snd_timer_id *id, struct snd_timer *timer)
1470 {
1471 	id->dev_class = timer->tmr_class;
1472 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1473 	id->card = timer->card ? timer->card->number : -1;
1474 	id->device = timer->tmr_device;
1475 	id->subdevice = timer->tmr_subdevice;
1476 }
1477 
1478 static int snd_timer_user_next_device(struct snd_timer_id __user *_tid)
1479 {
1480 	struct snd_timer_id id;
1481 	struct snd_timer *timer;
1482 	struct list_head *p;
1483 
1484 	if (copy_from_user(&id, _tid, sizeof(id)))
1485 		return -EFAULT;
1486 	mutex_lock(&register_mutex);
1487 	if (id.dev_class < 0) {		/* first item */
1488 		if (list_empty(&snd_timer_list))
1489 			snd_timer_user_zero_id(&id);
1490 		else {
1491 			timer = list_entry(snd_timer_list.next,
1492 					   struct snd_timer, device_list);
1493 			snd_timer_user_copy_id(&id, timer);
1494 		}
1495 	} else {
1496 		switch (id.dev_class) {
1497 		case SNDRV_TIMER_CLASS_GLOBAL:
1498 			id.device = id.device < 0 ? 0 : id.device + 1;
1499 			list_for_each(p, &snd_timer_list) {
1500 				timer = list_entry(p, struct snd_timer, device_list);
1501 				if (timer->tmr_class > SNDRV_TIMER_CLASS_GLOBAL) {
1502 					snd_timer_user_copy_id(&id, timer);
1503 					break;
1504 				}
1505 				if (timer->tmr_device >= id.device) {
1506 					snd_timer_user_copy_id(&id, timer);
1507 					break;
1508 				}
1509 			}
1510 			if (p == &snd_timer_list)
1511 				snd_timer_user_zero_id(&id);
1512 			break;
1513 		case SNDRV_TIMER_CLASS_CARD:
1514 		case SNDRV_TIMER_CLASS_PCM:
1515 			if (id.card < 0) {
1516 				id.card = 0;
1517 			} else {
1518 				if (id.device < 0) {
1519 					id.device = 0;
1520 				} else {
1521 					if (id.subdevice < 0)
1522 						id.subdevice = 0;
1523 					else if (id.subdevice < INT_MAX)
1524 						id.subdevice++;
1525 				}
1526 			}
1527 			list_for_each(p, &snd_timer_list) {
1528 				timer = list_entry(p, struct snd_timer, device_list);
1529 				if (timer->tmr_class > id.dev_class) {
1530 					snd_timer_user_copy_id(&id, timer);
1531 					break;
1532 				}
1533 				if (timer->tmr_class < id.dev_class)
1534 					continue;
1535 				if (timer->card->number > id.card) {
1536 					snd_timer_user_copy_id(&id, timer);
1537 					break;
1538 				}
1539 				if (timer->card->number < id.card)
1540 					continue;
1541 				if (timer->tmr_device > id.device) {
1542 					snd_timer_user_copy_id(&id, timer);
1543 					break;
1544 				}
1545 				if (timer->tmr_device < id.device)
1546 					continue;
1547 				if (timer->tmr_subdevice > id.subdevice) {
1548 					snd_timer_user_copy_id(&id, timer);
1549 					break;
1550 				}
1551 				if (timer->tmr_subdevice < id.subdevice)
1552 					continue;
1553 				snd_timer_user_copy_id(&id, timer);
1554 				break;
1555 			}
1556 			if (p == &snd_timer_list)
1557 				snd_timer_user_zero_id(&id);
1558 			break;
1559 		default:
1560 			snd_timer_user_zero_id(&id);
1561 		}
1562 	}
1563 	mutex_unlock(&register_mutex);
1564 	if (copy_to_user(_tid, &id, sizeof(*_tid)))
1565 		return -EFAULT;
1566 	return 0;
1567 }
1568 
1569 static int snd_timer_user_ginfo(struct file *file,
1570 				struct snd_timer_ginfo __user *_ginfo)
1571 {
1572 	struct snd_timer_ginfo *ginfo;
1573 	struct snd_timer_id tid;
1574 	struct snd_timer *t;
1575 	struct list_head *p;
1576 	int err = 0;
1577 
1578 	ginfo = memdup_user(_ginfo, sizeof(*ginfo));
1579 	if (IS_ERR(ginfo))
1580 		return PTR_ERR(ginfo);
1581 
1582 	tid = ginfo->tid;
1583 	memset(ginfo, 0, sizeof(*ginfo));
1584 	ginfo->tid = tid;
1585 	mutex_lock(&register_mutex);
1586 	t = snd_timer_find(&tid);
1587 	if (t != NULL) {
1588 		ginfo->card = t->card ? t->card->number : -1;
1589 		if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1590 			ginfo->flags |= SNDRV_TIMER_FLG_SLAVE;
1591 		strlcpy(ginfo->id, t->id, sizeof(ginfo->id));
1592 		strlcpy(ginfo->name, t->name, sizeof(ginfo->name));
1593 		ginfo->resolution = t->hw.resolution;
1594 		if (t->hw.resolution_min > 0) {
1595 			ginfo->resolution_min = t->hw.resolution_min;
1596 			ginfo->resolution_max = t->hw.resolution_max;
1597 		}
1598 		list_for_each(p, &t->open_list_head) {
1599 			ginfo->clients++;
1600 		}
1601 	} else {
1602 		err = -ENODEV;
1603 	}
1604 	mutex_unlock(&register_mutex);
1605 	if (err >= 0 && copy_to_user(_ginfo, ginfo, sizeof(*ginfo)))
1606 		err = -EFAULT;
1607 	kfree(ginfo);
1608 	return err;
1609 }
1610 
1611 static int timer_set_gparams(struct snd_timer_gparams *gparams)
1612 {
1613 	struct snd_timer *t;
1614 	int err;
1615 
1616 	mutex_lock(&register_mutex);
1617 	t = snd_timer_find(&gparams->tid);
1618 	if (!t) {
1619 		err = -ENODEV;
1620 		goto _error;
1621 	}
1622 	if (!list_empty(&t->open_list_head)) {
1623 		err = -EBUSY;
1624 		goto _error;
1625 	}
1626 	if (!t->hw.set_period) {
1627 		err = -ENOSYS;
1628 		goto _error;
1629 	}
1630 	err = t->hw.set_period(t, gparams->period_num, gparams->period_den);
1631 _error:
1632 	mutex_unlock(&register_mutex);
1633 	return err;
1634 }
1635 
1636 static int snd_timer_user_gparams(struct file *file,
1637 				  struct snd_timer_gparams __user *_gparams)
1638 {
1639 	struct snd_timer_gparams gparams;
1640 
1641 	if (copy_from_user(&gparams, _gparams, sizeof(gparams)))
1642 		return -EFAULT;
1643 	return timer_set_gparams(&gparams);
1644 }
1645 
1646 static int snd_timer_user_gstatus(struct file *file,
1647 				  struct snd_timer_gstatus __user *_gstatus)
1648 {
1649 	struct snd_timer_gstatus gstatus;
1650 	struct snd_timer_id tid;
1651 	struct snd_timer *t;
1652 	int err = 0;
1653 
1654 	if (copy_from_user(&gstatus, _gstatus, sizeof(gstatus)))
1655 		return -EFAULT;
1656 	tid = gstatus.tid;
1657 	memset(&gstatus, 0, sizeof(gstatus));
1658 	gstatus.tid = tid;
1659 	mutex_lock(&register_mutex);
1660 	t = snd_timer_find(&tid);
1661 	if (t != NULL) {
1662 		spin_lock_irq(&t->lock);
1663 		gstatus.resolution = snd_timer_hw_resolution(t);
1664 		if (t->hw.precise_resolution) {
1665 			t->hw.precise_resolution(t, &gstatus.resolution_num,
1666 						 &gstatus.resolution_den);
1667 		} else {
1668 			gstatus.resolution_num = gstatus.resolution;
1669 			gstatus.resolution_den = 1000000000uL;
1670 		}
1671 		spin_unlock_irq(&t->lock);
1672 	} else {
1673 		err = -ENODEV;
1674 	}
1675 	mutex_unlock(&register_mutex);
1676 	if (err >= 0 && copy_to_user(_gstatus, &gstatus, sizeof(gstatus)))
1677 		err = -EFAULT;
1678 	return err;
1679 }
1680 
1681 static int snd_timer_user_tselect(struct file *file,
1682 				  struct snd_timer_select __user *_tselect)
1683 {
1684 	struct snd_timer_user *tu;
1685 	struct snd_timer_select tselect;
1686 	char str[32];
1687 	int err = 0;
1688 
1689 	tu = file->private_data;
1690 	if (tu->timeri) {
1691 		snd_timer_close(tu->timeri);
1692 		tu->timeri = NULL;
1693 	}
1694 	if (copy_from_user(&tselect, _tselect, sizeof(tselect))) {
1695 		err = -EFAULT;
1696 		goto __err;
1697 	}
1698 	sprintf(str, "application %i", current->pid);
1699 	if (tselect.id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
1700 		tselect.id.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION;
1701 	err = snd_timer_open(&tu->timeri, str, &tselect.id, current->pid);
1702 	if (err < 0)
1703 		goto __err;
1704 
1705 	tu->timeri->flags |= SNDRV_TIMER_IFLG_FAST;
1706 	tu->timeri->callback = tu->tread
1707 			? snd_timer_user_tinterrupt : snd_timer_user_interrupt;
1708 	tu->timeri->ccallback = snd_timer_user_ccallback;
1709 	tu->timeri->callback_data = (void *)tu;
1710 	tu->timeri->disconnect = snd_timer_user_disconnect;
1711 
1712       __err:
1713 	return err;
1714 }
1715 
1716 static int snd_timer_user_info(struct file *file,
1717 			       struct snd_timer_info __user *_info)
1718 {
1719 	struct snd_timer_user *tu;
1720 	struct snd_timer_info *info;
1721 	struct snd_timer *t;
1722 	int err = 0;
1723 
1724 	tu = file->private_data;
1725 	if (!tu->timeri)
1726 		return -EBADFD;
1727 	t = tu->timeri->timer;
1728 	if (!t)
1729 		return -EBADFD;
1730 
1731 	info = kzalloc(sizeof(*info), GFP_KERNEL);
1732 	if (! info)
1733 		return -ENOMEM;
1734 	info->card = t->card ? t->card->number : -1;
1735 	if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1736 		info->flags |= SNDRV_TIMER_FLG_SLAVE;
1737 	strlcpy(info->id, t->id, sizeof(info->id));
1738 	strlcpy(info->name, t->name, sizeof(info->name));
1739 	info->resolution = t->hw.resolution;
1740 	if (copy_to_user(_info, info, sizeof(*_info)))
1741 		err = -EFAULT;
1742 	kfree(info);
1743 	return err;
1744 }
1745 
1746 static int snd_timer_user_params(struct file *file,
1747 				 struct snd_timer_params __user *_params)
1748 {
1749 	struct snd_timer_user *tu;
1750 	struct snd_timer_params params;
1751 	struct snd_timer *t;
1752 	int err;
1753 
1754 	tu = file->private_data;
1755 	if (!tu->timeri)
1756 		return -EBADFD;
1757 	t = tu->timeri->timer;
1758 	if (!t)
1759 		return -EBADFD;
1760 	if (copy_from_user(&params, _params, sizeof(params)))
1761 		return -EFAULT;
1762 	if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE)) {
1763 		u64 resolution;
1764 
1765 		if (params.ticks < 1) {
1766 			err = -EINVAL;
1767 			goto _end;
1768 		}
1769 
1770 		/* Don't allow resolution less than 1ms */
1771 		resolution = snd_timer_resolution(tu->timeri);
1772 		resolution *= params.ticks;
1773 		if (resolution < 1000000) {
1774 			err = -EINVAL;
1775 			goto _end;
1776 		}
1777 	}
1778 	if (params.queue_size > 0 &&
1779 	    (params.queue_size < 32 || params.queue_size > 1024)) {
1780 		err = -EINVAL;
1781 		goto _end;
1782 	}
1783 	if (params.filter & ~((1<<SNDRV_TIMER_EVENT_RESOLUTION)|
1784 			      (1<<SNDRV_TIMER_EVENT_TICK)|
1785 			      (1<<SNDRV_TIMER_EVENT_START)|
1786 			      (1<<SNDRV_TIMER_EVENT_STOP)|
1787 			      (1<<SNDRV_TIMER_EVENT_CONTINUE)|
1788 			      (1<<SNDRV_TIMER_EVENT_PAUSE)|
1789 			      (1<<SNDRV_TIMER_EVENT_SUSPEND)|
1790 			      (1<<SNDRV_TIMER_EVENT_RESUME)|
1791 			      (1<<SNDRV_TIMER_EVENT_MSTART)|
1792 			      (1<<SNDRV_TIMER_EVENT_MSTOP)|
1793 			      (1<<SNDRV_TIMER_EVENT_MCONTINUE)|
1794 			      (1<<SNDRV_TIMER_EVENT_MPAUSE)|
1795 			      (1<<SNDRV_TIMER_EVENT_MSUSPEND)|
1796 			      (1<<SNDRV_TIMER_EVENT_MRESUME))) {
1797 		err = -EINVAL;
1798 		goto _end;
1799 	}
1800 	snd_timer_stop(tu->timeri);
1801 	spin_lock_irq(&t->lock);
1802 	tu->timeri->flags &= ~(SNDRV_TIMER_IFLG_AUTO|
1803 			       SNDRV_TIMER_IFLG_EXCLUSIVE|
1804 			       SNDRV_TIMER_IFLG_EARLY_EVENT);
1805 	if (params.flags & SNDRV_TIMER_PSFLG_AUTO)
1806 		tu->timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1807 	if (params.flags & SNDRV_TIMER_PSFLG_EXCLUSIVE)
1808 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EXCLUSIVE;
1809 	if (params.flags & SNDRV_TIMER_PSFLG_EARLY_EVENT)
1810 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EARLY_EVENT;
1811 	spin_unlock_irq(&t->lock);
1812 	if (params.queue_size > 0 &&
1813 	    (unsigned int)tu->queue_size != params.queue_size) {
1814 		err = realloc_user_queue(tu, params.queue_size);
1815 		if (err < 0)
1816 			goto _end;
1817 	}
1818 	spin_lock_irq(&tu->qlock);
1819 	tu->qhead = tu->qtail = tu->qused = 0;
1820 	if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
1821 		if (tu->tread) {
1822 			struct snd_timer_tread tread;
1823 			memset(&tread, 0, sizeof(tread));
1824 			tread.event = SNDRV_TIMER_EVENT_EARLY;
1825 			tread.tstamp.tv_sec = 0;
1826 			tread.tstamp.tv_nsec = 0;
1827 			tread.val = 0;
1828 			snd_timer_user_append_to_tqueue(tu, &tread);
1829 		} else {
1830 			struct snd_timer_read *r = &tu->queue[0];
1831 			r->resolution = 0;
1832 			r->ticks = 0;
1833 			tu->qused++;
1834 			tu->qtail++;
1835 		}
1836 	}
1837 	tu->filter = params.filter;
1838 	tu->ticks = params.ticks;
1839 	spin_unlock_irq(&tu->qlock);
1840 	err = 0;
1841  _end:
1842 	if (copy_to_user(_params, &params, sizeof(params)))
1843 		return -EFAULT;
1844 	return err;
1845 }
1846 
1847 static int snd_timer_user_status(struct file *file,
1848 				 struct snd_timer_status __user *_status)
1849 {
1850 	struct snd_timer_user *tu;
1851 	struct snd_timer_status status;
1852 
1853 	tu = file->private_data;
1854 	if (!tu->timeri)
1855 		return -EBADFD;
1856 	memset(&status, 0, sizeof(status));
1857 	status.tstamp = tu->tstamp;
1858 	status.resolution = snd_timer_resolution(tu->timeri);
1859 	status.lost = tu->timeri->lost;
1860 	status.overrun = tu->overrun;
1861 	spin_lock_irq(&tu->qlock);
1862 	status.queue = tu->qused;
1863 	spin_unlock_irq(&tu->qlock);
1864 	if (copy_to_user(_status, &status, sizeof(status)))
1865 		return -EFAULT;
1866 	return 0;
1867 }
1868 
1869 static int snd_timer_user_start(struct file *file)
1870 {
1871 	int err;
1872 	struct snd_timer_user *tu;
1873 
1874 	tu = file->private_data;
1875 	if (!tu->timeri)
1876 		return -EBADFD;
1877 	snd_timer_stop(tu->timeri);
1878 	tu->timeri->lost = 0;
1879 	tu->last_resolution = 0;
1880 	return (err = snd_timer_start(tu->timeri, tu->ticks)) < 0 ? err : 0;
1881 }
1882 
1883 static int snd_timer_user_stop(struct file *file)
1884 {
1885 	int err;
1886 	struct snd_timer_user *tu;
1887 
1888 	tu = file->private_data;
1889 	if (!tu->timeri)
1890 		return -EBADFD;
1891 	return (err = snd_timer_stop(tu->timeri)) < 0 ? err : 0;
1892 }
1893 
1894 static int snd_timer_user_continue(struct file *file)
1895 {
1896 	int err;
1897 	struct snd_timer_user *tu;
1898 
1899 	tu = file->private_data;
1900 	if (!tu->timeri)
1901 		return -EBADFD;
1902 	/* start timer instead of continue if it's not used before */
1903 	if (!(tu->timeri->flags & SNDRV_TIMER_IFLG_PAUSED))
1904 		return snd_timer_user_start(file);
1905 	tu->timeri->lost = 0;
1906 	return (err = snd_timer_continue(tu->timeri)) < 0 ? err : 0;
1907 }
1908 
1909 static int snd_timer_user_pause(struct file *file)
1910 {
1911 	int err;
1912 	struct snd_timer_user *tu;
1913 
1914 	tu = file->private_data;
1915 	if (!tu->timeri)
1916 		return -EBADFD;
1917 	return (err = snd_timer_pause(tu->timeri)) < 0 ? err : 0;
1918 }
1919 
1920 enum {
1921 	SNDRV_TIMER_IOCTL_START_OLD = _IO('T', 0x20),
1922 	SNDRV_TIMER_IOCTL_STOP_OLD = _IO('T', 0x21),
1923 	SNDRV_TIMER_IOCTL_CONTINUE_OLD = _IO('T', 0x22),
1924 	SNDRV_TIMER_IOCTL_PAUSE_OLD = _IO('T', 0x23),
1925 };
1926 
1927 static long __snd_timer_user_ioctl(struct file *file, unsigned int cmd,
1928 				 unsigned long arg)
1929 {
1930 	struct snd_timer_user *tu;
1931 	void __user *argp = (void __user *)arg;
1932 	int __user *p = argp;
1933 
1934 	tu = file->private_data;
1935 	switch (cmd) {
1936 	case SNDRV_TIMER_IOCTL_PVERSION:
1937 		return put_user(SNDRV_TIMER_VERSION, p) ? -EFAULT : 0;
1938 	case SNDRV_TIMER_IOCTL_NEXT_DEVICE:
1939 		return snd_timer_user_next_device(argp);
1940 	case SNDRV_TIMER_IOCTL_TREAD:
1941 	{
1942 		int xarg, old_tread;
1943 
1944 		if (tu->timeri)	/* too late */
1945 			return -EBUSY;
1946 		if (get_user(xarg, p))
1947 			return -EFAULT;
1948 		old_tread = tu->tread;
1949 		tu->tread = xarg ? 1 : 0;
1950 		if (tu->tread != old_tread &&
1951 		    realloc_user_queue(tu, tu->queue_size) < 0) {
1952 			tu->tread = old_tread;
1953 			return -ENOMEM;
1954 		}
1955 		return 0;
1956 	}
1957 	case SNDRV_TIMER_IOCTL_GINFO:
1958 		return snd_timer_user_ginfo(file, argp);
1959 	case SNDRV_TIMER_IOCTL_GPARAMS:
1960 		return snd_timer_user_gparams(file, argp);
1961 	case SNDRV_TIMER_IOCTL_GSTATUS:
1962 		return snd_timer_user_gstatus(file, argp);
1963 	case SNDRV_TIMER_IOCTL_SELECT:
1964 		return snd_timer_user_tselect(file, argp);
1965 	case SNDRV_TIMER_IOCTL_INFO:
1966 		return snd_timer_user_info(file, argp);
1967 	case SNDRV_TIMER_IOCTL_PARAMS:
1968 		return snd_timer_user_params(file, argp);
1969 	case SNDRV_TIMER_IOCTL_STATUS:
1970 		return snd_timer_user_status(file, argp);
1971 	case SNDRV_TIMER_IOCTL_START:
1972 	case SNDRV_TIMER_IOCTL_START_OLD:
1973 		return snd_timer_user_start(file);
1974 	case SNDRV_TIMER_IOCTL_STOP:
1975 	case SNDRV_TIMER_IOCTL_STOP_OLD:
1976 		return snd_timer_user_stop(file);
1977 	case SNDRV_TIMER_IOCTL_CONTINUE:
1978 	case SNDRV_TIMER_IOCTL_CONTINUE_OLD:
1979 		return snd_timer_user_continue(file);
1980 	case SNDRV_TIMER_IOCTL_PAUSE:
1981 	case SNDRV_TIMER_IOCTL_PAUSE_OLD:
1982 		return snd_timer_user_pause(file);
1983 	}
1984 	return -ENOTTY;
1985 }
1986 
1987 static long snd_timer_user_ioctl(struct file *file, unsigned int cmd,
1988 				 unsigned long arg)
1989 {
1990 	struct snd_timer_user *tu = file->private_data;
1991 	long ret;
1992 
1993 	mutex_lock(&tu->ioctl_lock);
1994 	ret = __snd_timer_user_ioctl(file, cmd, arg);
1995 	mutex_unlock(&tu->ioctl_lock);
1996 	return ret;
1997 }
1998 
1999 static int snd_timer_user_fasync(int fd, struct file * file, int on)
2000 {
2001 	struct snd_timer_user *tu;
2002 
2003 	tu = file->private_data;
2004 	return fasync_helper(fd, file, on, &tu->fasync);
2005 }
2006 
2007 static ssize_t snd_timer_user_read(struct file *file, char __user *buffer,
2008 				   size_t count, loff_t *offset)
2009 {
2010 	struct snd_timer_user *tu;
2011 	long result = 0, unit;
2012 	int qhead;
2013 	int err = 0;
2014 
2015 	tu = file->private_data;
2016 	unit = tu->tread ? sizeof(struct snd_timer_tread) : sizeof(struct snd_timer_read);
2017 	mutex_lock(&tu->ioctl_lock);
2018 	spin_lock_irq(&tu->qlock);
2019 	while ((long)count - result >= unit) {
2020 		while (!tu->qused) {
2021 			wait_queue_entry_t wait;
2022 
2023 			if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
2024 				err = -EAGAIN;
2025 				goto _error;
2026 			}
2027 
2028 			set_current_state(TASK_INTERRUPTIBLE);
2029 			init_waitqueue_entry(&wait, current);
2030 			add_wait_queue(&tu->qchange_sleep, &wait);
2031 
2032 			spin_unlock_irq(&tu->qlock);
2033 			mutex_unlock(&tu->ioctl_lock);
2034 			schedule();
2035 			mutex_lock(&tu->ioctl_lock);
2036 			spin_lock_irq(&tu->qlock);
2037 
2038 			remove_wait_queue(&tu->qchange_sleep, &wait);
2039 
2040 			if (tu->disconnected) {
2041 				err = -ENODEV;
2042 				goto _error;
2043 			}
2044 			if (signal_pending(current)) {
2045 				err = -ERESTARTSYS;
2046 				goto _error;
2047 			}
2048 		}
2049 
2050 		qhead = tu->qhead++;
2051 		tu->qhead %= tu->queue_size;
2052 		tu->qused--;
2053 		spin_unlock_irq(&tu->qlock);
2054 
2055 		if (tu->tread) {
2056 			if (copy_to_user(buffer, &tu->tqueue[qhead],
2057 					 sizeof(struct snd_timer_tread)))
2058 				err = -EFAULT;
2059 		} else {
2060 			if (copy_to_user(buffer, &tu->queue[qhead],
2061 					 sizeof(struct snd_timer_read)))
2062 				err = -EFAULT;
2063 		}
2064 
2065 		spin_lock_irq(&tu->qlock);
2066 		if (err < 0)
2067 			goto _error;
2068 		result += unit;
2069 		buffer += unit;
2070 	}
2071  _error:
2072 	spin_unlock_irq(&tu->qlock);
2073 	mutex_unlock(&tu->ioctl_lock);
2074 	return result > 0 ? result : err;
2075 }
2076 
2077 static __poll_t snd_timer_user_poll(struct file *file, poll_table * wait)
2078 {
2079         __poll_t mask;
2080         struct snd_timer_user *tu;
2081 
2082         tu = file->private_data;
2083 
2084         poll_wait(file, &tu->qchange_sleep, wait);
2085 
2086 	mask = 0;
2087 	spin_lock_irq(&tu->qlock);
2088 	if (tu->qused)
2089 		mask |= EPOLLIN | EPOLLRDNORM;
2090 	if (tu->disconnected)
2091 		mask |= EPOLLERR;
2092 	spin_unlock_irq(&tu->qlock);
2093 
2094 	return mask;
2095 }
2096 
2097 #ifdef CONFIG_COMPAT
2098 #include "timer_compat.c"
2099 #else
2100 #define snd_timer_user_ioctl_compat	NULL
2101 #endif
2102 
2103 static const struct file_operations snd_timer_f_ops =
2104 {
2105 	.owner =	THIS_MODULE,
2106 	.read =		snd_timer_user_read,
2107 	.open =		snd_timer_user_open,
2108 	.release =	snd_timer_user_release,
2109 	.llseek =	no_llseek,
2110 	.poll =		snd_timer_user_poll,
2111 	.unlocked_ioctl =	snd_timer_user_ioctl,
2112 	.compat_ioctl =	snd_timer_user_ioctl_compat,
2113 	.fasync = 	snd_timer_user_fasync,
2114 };
2115 
2116 /* unregister the system timer */
2117 static void snd_timer_free_all(void)
2118 {
2119 	struct snd_timer *timer, *n;
2120 
2121 	list_for_each_entry_safe(timer, n, &snd_timer_list, device_list)
2122 		snd_timer_free(timer);
2123 }
2124 
2125 static struct device timer_dev;
2126 
2127 /*
2128  *  ENTRY functions
2129  */
2130 
2131 static int __init alsa_timer_init(void)
2132 {
2133 	int err;
2134 
2135 	snd_device_initialize(&timer_dev, NULL);
2136 	dev_set_name(&timer_dev, "timer");
2137 
2138 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
2139 	snd_oss_info_register(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1,
2140 			      "system timer");
2141 #endif
2142 
2143 	err = snd_timer_register_system();
2144 	if (err < 0) {
2145 		pr_err("ALSA: unable to register system timer (%i)\n", err);
2146 		goto put_timer;
2147 	}
2148 
2149 	err = snd_register_device(SNDRV_DEVICE_TYPE_TIMER, NULL, 0,
2150 				  &snd_timer_f_ops, NULL, &timer_dev);
2151 	if (err < 0) {
2152 		pr_err("ALSA: unable to register timer device (%i)\n", err);
2153 		snd_timer_free_all();
2154 		goto put_timer;
2155 	}
2156 
2157 	snd_timer_proc_init();
2158 	return 0;
2159 
2160 put_timer:
2161 	put_device(&timer_dev);
2162 	return err;
2163 }
2164 
2165 static void __exit alsa_timer_exit(void)
2166 {
2167 	snd_unregister_device(&timer_dev);
2168 	snd_timer_free_all();
2169 	put_device(&timer_dev);
2170 	snd_timer_proc_done();
2171 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
2172 	snd_oss_info_unregister(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1);
2173 #endif
2174 }
2175 
2176 module_init(alsa_timer_init)
2177 module_exit(alsa_timer_exit)
2178