xref: /openbmc/linux/sound/core/timer.c (revision bb121128)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Timers abstract layer
4  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
5  */
6 
7 #include <linux/delay.h>
8 #include <linux/init.h>
9 #include <linux/slab.h>
10 #include <linux/time.h>
11 #include <linux/mutex.h>
12 #include <linux/device.h>
13 #include <linux/module.h>
14 #include <linux/string.h>
15 #include <linux/sched/signal.h>
16 #include <sound/core.h>
17 #include <sound/timer.h>
18 #include <sound/control.h>
19 #include <sound/info.h>
20 #include <sound/minors.h>
21 #include <sound/initval.h>
22 #include <linux/kmod.h>
23 
24 /* internal flags */
25 #define SNDRV_TIMER_IFLG_PAUSED		0x00010000
26 #define SNDRV_TIMER_IFLG_DEAD		0x00020000
27 
28 #if IS_ENABLED(CONFIG_SND_HRTIMER)
29 #define DEFAULT_TIMER_LIMIT 4
30 #else
31 #define DEFAULT_TIMER_LIMIT 1
32 #endif
33 
34 static int timer_limit = DEFAULT_TIMER_LIMIT;
35 static int timer_tstamp_monotonic = 1;
36 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.de>");
37 MODULE_DESCRIPTION("ALSA timer interface");
38 MODULE_LICENSE("GPL");
39 module_param(timer_limit, int, 0444);
40 MODULE_PARM_DESC(timer_limit, "Maximum global timers in system.");
41 module_param(timer_tstamp_monotonic, int, 0444);
42 MODULE_PARM_DESC(timer_tstamp_monotonic, "Use posix monotonic clock source for timestamps (default).");
43 
44 MODULE_ALIAS_CHARDEV(CONFIG_SND_MAJOR, SNDRV_MINOR_TIMER);
45 MODULE_ALIAS("devname:snd/timer");
46 
47 enum timer_tread_format {
48 	TREAD_FORMAT_NONE = 0,
49 	TREAD_FORMAT_TIME64,
50 	TREAD_FORMAT_TIME32,
51 };
52 
53 struct snd_timer_tread32 {
54 	int event;
55 	s32 tstamp_sec;
56 	s32 tstamp_nsec;
57 	unsigned int val;
58 };
59 
60 struct snd_timer_tread64 {
61 	int event;
62 	u8 pad1[4];
63 	s64 tstamp_sec;
64 	s64 tstamp_nsec;
65 	unsigned int val;
66 	u8 pad2[4];
67 };
68 
69 struct snd_timer_user {
70 	struct snd_timer_instance *timeri;
71 	int tread;		/* enhanced read with timestamps and events */
72 	unsigned long ticks;
73 	unsigned long overrun;
74 	int qhead;
75 	int qtail;
76 	int qused;
77 	int queue_size;
78 	bool disconnected;
79 	struct snd_timer_read *queue;
80 	struct snd_timer_tread64 *tqueue;
81 	spinlock_t qlock;
82 	unsigned long last_resolution;
83 	unsigned int filter;
84 	struct timespec64 tstamp;		/* trigger tstamp */
85 	wait_queue_head_t qchange_sleep;
86 	struct snd_fasync *fasync;
87 	struct mutex ioctl_lock;
88 };
89 
90 struct snd_timer_status32 {
91 	s32 tstamp_sec;			/* Timestamp - last update */
92 	s32 tstamp_nsec;
93 	unsigned int resolution;	/* current period resolution in ns */
94 	unsigned int lost;		/* counter of master tick lost */
95 	unsigned int overrun;		/* count of read queue overruns */
96 	unsigned int queue;		/* used queue size */
97 	unsigned char reserved[64];	/* reserved */
98 };
99 
100 #define SNDRV_TIMER_IOCTL_STATUS32	_IOR('T', 0x14, struct snd_timer_status32)
101 
102 struct snd_timer_status64 {
103 	s64 tstamp_sec;			/* Timestamp - last update */
104 	s64 tstamp_nsec;
105 	unsigned int resolution;	/* current period resolution in ns */
106 	unsigned int lost;		/* counter of master tick lost */
107 	unsigned int overrun;		/* count of read queue overruns */
108 	unsigned int queue;		/* used queue size */
109 	unsigned char reserved[64];	/* reserved */
110 };
111 
112 #define SNDRV_TIMER_IOCTL_STATUS64	_IOR('T', 0x14, struct snd_timer_status64)
113 
114 /* list of timers */
115 static LIST_HEAD(snd_timer_list);
116 
117 /* list of slave instances */
118 static LIST_HEAD(snd_timer_slave_list);
119 
120 /* lock for slave active lists */
121 static DEFINE_SPINLOCK(slave_active_lock);
122 
123 #define MAX_SLAVE_INSTANCES	1000
124 static int num_slaves;
125 
126 static DEFINE_MUTEX(register_mutex);
127 
128 static int snd_timer_free(struct snd_timer *timer);
129 static int snd_timer_dev_free(struct snd_device *device);
130 static int snd_timer_dev_register(struct snd_device *device);
131 static int snd_timer_dev_disconnect(struct snd_device *device);
132 
133 static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left);
134 
135 /*
136  * create a timer instance with the given owner string.
137  */
snd_timer_instance_new(const char * owner)138 struct snd_timer_instance *snd_timer_instance_new(const char *owner)
139 {
140 	struct snd_timer_instance *timeri;
141 
142 	timeri = kzalloc(sizeof(*timeri), GFP_KERNEL);
143 	if (timeri == NULL)
144 		return NULL;
145 	timeri->owner = kstrdup(owner, GFP_KERNEL);
146 	if (! timeri->owner) {
147 		kfree(timeri);
148 		return NULL;
149 	}
150 	INIT_LIST_HEAD(&timeri->open_list);
151 	INIT_LIST_HEAD(&timeri->active_list);
152 	INIT_LIST_HEAD(&timeri->ack_list);
153 	INIT_LIST_HEAD(&timeri->slave_list_head);
154 	INIT_LIST_HEAD(&timeri->slave_active_head);
155 
156 	return timeri;
157 }
158 EXPORT_SYMBOL(snd_timer_instance_new);
159 
snd_timer_instance_free(struct snd_timer_instance * timeri)160 void snd_timer_instance_free(struct snd_timer_instance *timeri)
161 {
162 	if (timeri) {
163 		if (timeri->private_free)
164 			timeri->private_free(timeri);
165 		kfree(timeri->owner);
166 		kfree(timeri);
167 	}
168 }
169 EXPORT_SYMBOL(snd_timer_instance_free);
170 
171 /*
172  * find a timer instance from the given timer id
173  */
snd_timer_find(struct snd_timer_id * tid)174 static struct snd_timer *snd_timer_find(struct snd_timer_id *tid)
175 {
176 	struct snd_timer *timer;
177 
178 	list_for_each_entry(timer, &snd_timer_list, device_list) {
179 		if (timer->tmr_class != tid->dev_class)
180 			continue;
181 		if ((timer->tmr_class == SNDRV_TIMER_CLASS_CARD ||
182 		     timer->tmr_class == SNDRV_TIMER_CLASS_PCM) &&
183 		    (timer->card == NULL ||
184 		     timer->card->number != tid->card))
185 			continue;
186 		if (timer->tmr_device != tid->device)
187 			continue;
188 		if (timer->tmr_subdevice != tid->subdevice)
189 			continue;
190 		return timer;
191 	}
192 	return NULL;
193 }
194 
195 #ifdef CONFIG_MODULES
196 
snd_timer_request(struct snd_timer_id * tid)197 static void snd_timer_request(struct snd_timer_id *tid)
198 {
199 	switch (tid->dev_class) {
200 	case SNDRV_TIMER_CLASS_GLOBAL:
201 		if (tid->device < timer_limit)
202 			request_module("snd-timer-%i", tid->device);
203 		break;
204 	case SNDRV_TIMER_CLASS_CARD:
205 	case SNDRV_TIMER_CLASS_PCM:
206 		if (tid->card < snd_ecards_limit)
207 			request_module("snd-card-%i", tid->card);
208 		break;
209 	default:
210 		break;
211 	}
212 }
213 
214 #endif
215 
216 /* move the slave if it belongs to the master; return 1 if match */
check_matching_master_slave(struct snd_timer_instance * master,struct snd_timer_instance * slave)217 static int check_matching_master_slave(struct snd_timer_instance *master,
218 				       struct snd_timer_instance *slave)
219 {
220 	if (slave->slave_class != master->slave_class ||
221 	    slave->slave_id != master->slave_id)
222 		return 0;
223 	if (master->timer->num_instances >= master->timer->max_instances)
224 		return -EBUSY;
225 	list_move_tail(&slave->open_list, &master->slave_list_head);
226 	master->timer->num_instances++;
227 	spin_lock_irq(&slave_active_lock);
228 	spin_lock(&master->timer->lock);
229 	slave->master = master;
230 	slave->timer = master->timer;
231 	if (slave->flags & SNDRV_TIMER_IFLG_RUNNING)
232 		list_add_tail(&slave->active_list, &master->slave_active_head);
233 	spin_unlock(&master->timer->lock);
234 	spin_unlock_irq(&slave_active_lock);
235 	return 1;
236 }
237 
238 /*
239  * look for a master instance matching with the slave id of the given slave.
240  * when found, relink the open_link of the slave.
241  *
242  * call this with register_mutex down.
243  */
snd_timer_check_slave(struct snd_timer_instance * slave)244 static int snd_timer_check_slave(struct snd_timer_instance *slave)
245 {
246 	struct snd_timer *timer;
247 	struct snd_timer_instance *master;
248 	int err = 0;
249 
250 	/* FIXME: it's really dumb to look up all entries.. */
251 	list_for_each_entry(timer, &snd_timer_list, device_list) {
252 		list_for_each_entry(master, &timer->open_list_head, open_list) {
253 			err = check_matching_master_slave(master, slave);
254 			if (err != 0) /* match found or error */
255 				goto out;
256 		}
257 	}
258  out:
259 	return err < 0 ? err : 0;
260 }
261 
262 /*
263  * look for slave instances matching with the slave id of the given master.
264  * when found, relink the open_link of slaves.
265  *
266  * call this with register_mutex down.
267  */
snd_timer_check_master(struct snd_timer_instance * master)268 static int snd_timer_check_master(struct snd_timer_instance *master)
269 {
270 	struct snd_timer_instance *slave, *tmp;
271 	int err = 0;
272 
273 	/* check all pending slaves */
274 	list_for_each_entry_safe(slave, tmp, &snd_timer_slave_list, open_list) {
275 		err = check_matching_master_slave(master, slave);
276 		if (err < 0)
277 			break;
278 	}
279 	return err < 0 ? err : 0;
280 }
281 
282 static void snd_timer_close_locked(struct snd_timer_instance *timeri,
283 				   struct device **card_devp_to_put);
284 
285 /*
286  * open a timer instance
287  * when opening a master, the slave id must be here given.
288  */
snd_timer_open(struct snd_timer_instance * timeri,struct snd_timer_id * tid,unsigned int slave_id)289 int snd_timer_open(struct snd_timer_instance *timeri,
290 		   struct snd_timer_id *tid,
291 		   unsigned int slave_id)
292 {
293 	struct snd_timer *timer;
294 	struct device *card_dev_to_put = NULL;
295 	int err;
296 
297 	mutex_lock(&register_mutex);
298 	if (tid->dev_class == SNDRV_TIMER_CLASS_SLAVE) {
299 		/* open a slave instance */
300 		if (tid->dev_sclass <= SNDRV_TIMER_SCLASS_NONE ||
301 		    tid->dev_sclass > SNDRV_TIMER_SCLASS_OSS_SEQUENCER) {
302 			pr_debug("ALSA: timer: invalid slave class %i\n",
303 				 tid->dev_sclass);
304 			err = -EINVAL;
305 			goto unlock;
306 		}
307 		if (num_slaves >= MAX_SLAVE_INSTANCES) {
308 			err = -EBUSY;
309 			goto unlock;
310 		}
311 		timeri->slave_class = tid->dev_sclass;
312 		timeri->slave_id = tid->device;
313 		timeri->flags |= SNDRV_TIMER_IFLG_SLAVE;
314 		list_add_tail(&timeri->open_list, &snd_timer_slave_list);
315 		num_slaves++;
316 		err = snd_timer_check_slave(timeri);
317 		goto list_added;
318 	}
319 
320 	/* open a master instance */
321 	timer = snd_timer_find(tid);
322 #ifdef CONFIG_MODULES
323 	if (!timer) {
324 		mutex_unlock(&register_mutex);
325 		snd_timer_request(tid);
326 		mutex_lock(&register_mutex);
327 		timer = snd_timer_find(tid);
328 	}
329 #endif
330 	if (!timer) {
331 		err = -ENODEV;
332 		goto unlock;
333 	}
334 	if (!list_empty(&timer->open_list_head)) {
335 		struct snd_timer_instance *t =
336 			list_entry(timer->open_list_head.next,
337 				    struct snd_timer_instance, open_list);
338 		if (t->flags & SNDRV_TIMER_IFLG_EXCLUSIVE) {
339 			err = -EBUSY;
340 			goto unlock;
341 		}
342 	}
343 	if (timer->num_instances >= timer->max_instances) {
344 		err = -EBUSY;
345 		goto unlock;
346 	}
347 	if (!try_module_get(timer->module)) {
348 		err = -EBUSY;
349 		goto unlock;
350 	}
351 	/* take a card refcount for safe disconnection */
352 	if (timer->card) {
353 		get_device(&timer->card->card_dev);
354 		card_dev_to_put = &timer->card->card_dev;
355 	}
356 
357 	if (list_empty(&timer->open_list_head) && timer->hw.open) {
358 		err = timer->hw.open(timer);
359 		if (err) {
360 			module_put(timer->module);
361 			goto unlock;
362 		}
363 	}
364 
365 	timeri->timer = timer;
366 	timeri->slave_class = tid->dev_sclass;
367 	timeri->slave_id = slave_id;
368 
369 	list_add_tail(&timeri->open_list, &timer->open_list_head);
370 	timer->num_instances++;
371 	err = snd_timer_check_master(timeri);
372 list_added:
373 	if (err < 0)
374 		snd_timer_close_locked(timeri, &card_dev_to_put);
375 
376  unlock:
377 	mutex_unlock(&register_mutex);
378 	/* put_device() is called after unlock for avoiding deadlock */
379 	if (err < 0 && card_dev_to_put)
380 		put_device(card_dev_to_put);
381 	return err;
382 }
383 EXPORT_SYMBOL(snd_timer_open);
384 
385 /*
386  * close a timer instance
387  * call this with register_mutex down.
388  */
snd_timer_close_locked(struct snd_timer_instance * timeri,struct device ** card_devp_to_put)389 static void snd_timer_close_locked(struct snd_timer_instance *timeri,
390 				   struct device **card_devp_to_put)
391 {
392 	struct snd_timer *timer = timeri->timer;
393 	struct snd_timer_instance *slave, *tmp;
394 
395 	if (timer) {
396 		spin_lock_irq(&timer->lock);
397 		timeri->flags |= SNDRV_TIMER_IFLG_DEAD;
398 		spin_unlock_irq(&timer->lock);
399 	}
400 
401 	if (!list_empty(&timeri->open_list)) {
402 		list_del_init(&timeri->open_list);
403 		if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
404 			num_slaves--;
405 	}
406 
407 	/* force to stop the timer */
408 	snd_timer_stop(timeri);
409 
410 	if (timer) {
411 		timer->num_instances--;
412 		/* wait, until the active callback is finished */
413 		spin_lock_irq(&timer->lock);
414 		while (timeri->flags & SNDRV_TIMER_IFLG_CALLBACK) {
415 			spin_unlock_irq(&timer->lock);
416 			udelay(10);
417 			spin_lock_irq(&timer->lock);
418 		}
419 		spin_unlock_irq(&timer->lock);
420 
421 		/* remove slave links */
422 		spin_lock_irq(&slave_active_lock);
423 		spin_lock(&timer->lock);
424 		timeri->timer = NULL;
425 		list_for_each_entry_safe(slave, tmp, &timeri->slave_list_head,
426 					 open_list) {
427 			list_move_tail(&slave->open_list, &snd_timer_slave_list);
428 			timer->num_instances--;
429 			slave->master = NULL;
430 			slave->timer = NULL;
431 			list_del_init(&slave->ack_list);
432 			list_del_init(&slave->active_list);
433 		}
434 		spin_unlock(&timer->lock);
435 		spin_unlock_irq(&slave_active_lock);
436 
437 		/* slave doesn't need to release timer resources below */
438 		if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
439 			timer = NULL;
440 	}
441 
442 	if (timer) {
443 		if (list_empty(&timer->open_list_head) && timer->hw.close)
444 			timer->hw.close(timer);
445 		/* release a card refcount for safe disconnection */
446 		if (timer->card)
447 			*card_devp_to_put = &timer->card->card_dev;
448 		module_put(timer->module);
449 	}
450 }
451 
452 /*
453  * close a timer instance
454  */
snd_timer_close(struct snd_timer_instance * timeri)455 void snd_timer_close(struct snd_timer_instance *timeri)
456 {
457 	struct device *card_dev_to_put = NULL;
458 
459 	if (snd_BUG_ON(!timeri))
460 		return;
461 
462 	mutex_lock(&register_mutex);
463 	snd_timer_close_locked(timeri, &card_dev_to_put);
464 	mutex_unlock(&register_mutex);
465 	/* put_device() is called after unlock for avoiding deadlock */
466 	if (card_dev_to_put)
467 		put_device(card_dev_to_put);
468 }
469 EXPORT_SYMBOL(snd_timer_close);
470 
snd_timer_hw_resolution(struct snd_timer * timer)471 static unsigned long snd_timer_hw_resolution(struct snd_timer *timer)
472 {
473 	if (timer->hw.c_resolution)
474 		return timer->hw.c_resolution(timer);
475 	else
476 		return timer->hw.resolution;
477 }
478 
snd_timer_resolution(struct snd_timer_instance * timeri)479 unsigned long snd_timer_resolution(struct snd_timer_instance *timeri)
480 {
481 	struct snd_timer * timer;
482 	unsigned long ret = 0;
483 	unsigned long flags;
484 
485 	if (timeri == NULL)
486 		return 0;
487 	timer = timeri->timer;
488 	if (timer) {
489 		spin_lock_irqsave(&timer->lock, flags);
490 		ret = snd_timer_hw_resolution(timer);
491 		spin_unlock_irqrestore(&timer->lock, flags);
492 	}
493 	return ret;
494 }
495 EXPORT_SYMBOL(snd_timer_resolution);
496 
snd_timer_notify1(struct snd_timer_instance * ti,int event)497 static void snd_timer_notify1(struct snd_timer_instance *ti, int event)
498 {
499 	struct snd_timer *timer = ti->timer;
500 	unsigned long resolution = 0;
501 	struct snd_timer_instance *ts;
502 	struct timespec64 tstamp;
503 
504 	if (timer_tstamp_monotonic)
505 		ktime_get_ts64(&tstamp);
506 	else
507 		ktime_get_real_ts64(&tstamp);
508 	if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_START ||
509 		       event > SNDRV_TIMER_EVENT_PAUSE))
510 		return;
511 	if (timer &&
512 	    (event == SNDRV_TIMER_EVENT_START ||
513 	     event == SNDRV_TIMER_EVENT_CONTINUE))
514 		resolution = snd_timer_hw_resolution(timer);
515 	if (ti->ccallback)
516 		ti->ccallback(ti, event, &tstamp, resolution);
517 	if (ti->flags & SNDRV_TIMER_IFLG_SLAVE)
518 		return;
519 	if (timer == NULL)
520 		return;
521 	if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
522 		return;
523 	event += 10; /* convert to SNDRV_TIMER_EVENT_MXXX */
524 	list_for_each_entry(ts, &ti->slave_active_head, active_list)
525 		if (ts->ccallback)
526 			ts->ccallback(ts, event, &tstamp, resolution);
527 }
528 
529 /* start/continue a master timer */
snd_timer_start1(struct snd_timer_instance * timeri,bool start,unsigned long ticks)530 static int snd_timer_start1(struct snd_timer_instance *timeri,
531 			    bool start, unsigned long ticks)
532 {
533 	struct snd_timer *timer;
534 	int result;
535 	unsigned long flags;
536 
537 	timer = timeri->timer;
538 	if (!timer)
539 		return -EINVAL;
540 
541 	spin_lock_irqsave(&timer->lock, flags);
542 	if (timeri->flags & SNDRV_TIMER_IFLG_DEAD) {
543 		result = -EINVAL;
544 		goto unlock;
545 	}
546 	if (timer->card && timer->card->shutdown) {
547 		result = -ENODEV;
548 		goto unlock;
549 	}
550 	if (timeri->flags & (SNDRV_TIMER_IFLG_RUNNING |
551 			     SNDRV_TIMER_IFLG_START)) {
552 		result = -EBUSY;
553 		goto unlock;
554 	}
555 
556 	/* check the actual time for the start tick;
557 	 * bail out as error if it's way too low (< 100us)
558 	 */
559 	if (start && !(timer->hw.flags & SNDRV_TIMER_HW_SLAVE)) {
560 		if ((u64)snd_timer_hw_resolution(timer) * ticks < 100000) {
561 			result = -EINVAL;
562 			goto unlock;
563 		}
564 	}
565 
566 	if (start)
567 		timeri->ticks = timeri->cticks = ticks;
568 	else if (!timeri->cticks)
569 		timeri->cticks = 1;
570 	timeri->pticks = 0;
571 
572 	list_move_tail(&timeri->active_list, &timer->active_list_head);
573 	if (timer->running) {
574 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
575 			goto __start_now;
576 		timer->flags |= SNDRV_TIMER_FLG_RESCHED;
577 		timeri->flags |= SNDRV_TIMER_IFLG_START;
578 		result = 1; /* delayed start */
579 	} else {
580 		if (start)
581 			timer->sticks = ticks;
582 		timer->hw.start(timer);
583 	      __start_now:
584 		timer->running++;
585 		timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
586 		result = 0;
587 	}
588 	snd_timer_notify1(timeri, start ? SNDRV_TIMER_EVENT_START :
589 			  SNDRV_TIMER_EVENT_CONTINUE);
590  unlock:
591 	spin_unlock_irqrestore(&timer->lock, flags);
592 	return result;
593 }
594 
595 /* start/continue a slave timer */
snd_timer_start_slave(struct snd_timer_instance * timeri,bool start)596 static int snd_timer_start_slave(struct snd_timer_instance *timeri,
597 				 bool start)
598 {
599 	unsigned long flags;
600 	int err;
601 
602 	spin_lock_irqsave(&slave_active_lock, flags);
603 	if (timeri->flags & SNDRV_TIMER_IFLG_DEAD) {
604 		err = -EINVAL;
605 		goto unlock;
606 	}
607 	if (timeri->flags & SNDRV_TIMER_IFLG_RUNNING) {
608 		err = -EBUSY;
609 		goto unlock;
610 	}
611 	timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
612 	if (timeri->master && timeri->timer) {
613 		spin_lock(&timeri->timer->lock);
614 		list_add_tail(&timeri->active_list,
615 			      &timeri->master->slave_active_head);
616 		snd_timer_notify1(timeri, start ? SNDRV_TIMER_EVENT_START :
617 				  SNDRV_TIMER_EVENT_CONTINUE);
618 		spin_unlock(&timeri->timer->lock);
619 	}
620 	err = 1; /* delayed start */
621  unlock:
622 	spin_unlock_irqrestore(&slave_active_lock, flags);
623 	return err;
624 }
625 
626 /* stop/pause a master timer */
snd_timer_stop1(struct snd_timer_instance * timeri,bool stop)627 static int snd_timer_stop1(struct snd_timer_instance *timeri, bool stop)
628 {
629 	struct snd_timer *timer;
630 	int result = 0;
631 	unsigned long flags;
632 
633 	timer = timeri->timer;
634 	if (!timer)
635 		return -EINVAL;
636 	spin_lock_irqsave(&timer->lock, flags);
637 	list_del_init(&timeri->ack_list);
638 	list_del_init(&timeri->active_list);
639 	if (!(timeri->flags & (SNDRV_TIMER_IFLG_RUNNING |
640 			       SNDRV_TIMER_IFLG_START))) {
641 		result = -EBUSY;
642 		goto unlock;
643 	}
644 	if (timer->card && timer->card->shutdown)
645 		goto unlock;
646 	if (stop) {
647 		timeri->cticks = timeri->ticks;
648 		timeri->pticks = 0;
649 	}
650 	if ((timeri->flags & SNDRV_TIMER_IFLG_RUNNING) &&
651 	    !(--timer->running)) {
652 		timer->hw.stop(timer);
653 		if (timer->flags & SNDRV_TIMER_FLG_RESCHED) {
654 			timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
655 			snd_timer_reschedule(timer, 0);
656 			if (timer->flags & SNDRV_TIMER_FLG_CHANGE) {
657 				timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
658 				timer->hw.start(timer);
659 			}
660 		}
661 	}
662 	timeri->flags &= ~(SNDRV_TIMER_IFLG_RUNNING | SNDRV_TIMER_IFLG_START);
663 	if (stop)
664 		timeri->flags &= ~SNDRV_TIMER_IFLG_PAUSED;
665 	else
666 		timeri->flags |= SNDRV_TIMER_IFLG_PAUSED;
667 	snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :
668 			  SNDRV_TIMER_EVENT_PAUSE);
669  unlock:
670 	spin_unlock_irqrestore(&timer->lock, flags);
671 	return result;
672 }
673 
674 /* stop/pause a slave timer */
snd_timer_stop_slave(struct snd_timer_instance * timeri,bool stop)675 static int snd_timer_stop_slave(struct snd_timer_instance *timeri, bool stop)
676 {
677 	unsigned long flags;
678 	bool running;
679 
680 	spin_lock_irqsave(&slave_active_lock, flags);
681 	running = timeri->flags & SNDRV_TIMER_IFLG_RUNNING;
682 	timeri->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
683 	if (timeri->timer) {
684 		spin_lock(&timeri->timer->lock);
685 		list_del_init(&timeri->ack_list);
686 		list_del_init(&timeri->active_list);
687 		if (running)
688 			snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :
689 					  SNDRV_TIMER_EVENT_PAUSE);
690 		spin_unlock(&timeri->timer->lock);
691 	}
692 	spin_unlock_irqrestore(&slave_active_lock, flags);
693 	return running ? 0 : -EBUSY;
694 }
695 
696 /*
697  *  start the timer instance
698  */
snd_timer_start(struct snd_timer_instance * timeri,unsigned int ticks)699 int snd_timer_start(struct snd_timer_instance *timeri, unsigned int ticks)
700 {
701 	if (timeri == NULL || ticks < 1)
702 		return -EINVAL;
703 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
704 		return snd_timer_start_slave(timeri, true);
705 	else
706 		return snd_timer_start1(timeri, true, ticks);
707 }
708 EXPORT_SYMBOL(snd_timer_start);
709 
710 /*
711  * stop the timer instance.
712  *
713  * do not call this from the timer callback!
714  */
snd_timer_stop(struct snd_timer_instance * timeri)715 int snd_timer_stop(struct snd_timer_instance *timeri)
716 {
717 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
718 		return snd_timer_stop_slave(timeri, true);
719 	else
720 		return snd_timer_stop1(timeri, true);
721 }
722 EXPORT_SYMBOL(snd_timer_stop);
723 
724 /*
725  * start again..  the tick is kept.
726  */
snd_timer_continue(struct snd_timer_instance * timeri)727 int snd_timer_continue(struct snd_timer_instance *timeri)
728 {
729 	/* timer can continue only after pause */
730 	if (!(timeri->flags & SNDRV_TIMER_IFLG_PAUSED))
731 		return -EINVAL;
732 
733 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
734 		return snd_timer_start_slave(timeri, false);
735 	else
736 		return snd_timer_start1(timeri, false, 0);
737 }
738 EXPORT_SYMBOL(snd_timer_continue);
739 
740 /*
741  * pause.. remember the ticks left
742  */
snd_timer_pause(struct snd_timer_instance * timeri)743 int snd_timer_pause(struct snd_timer_instance * timeri)
744 {
745 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
746 		return snd_timer_stop_slave(timeri, false);
747 	else
748 		return snd_timer_stop1(timeri, false);
749 }
750 EXPORT_SYMBOL(snd_timer_pause);
751 
752 /*
753  * reschedule the timer
754  *
755  * start pending instances and check the scheduling ticks.
756  * when the scheduling ticks is changed set CHANGE flag to reprogram the timer.
757  */
snd_timer_reschedule(struct snd_timer * timer,unsigned long ticks_left)758 static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left)
759 {
760 	struct snd_timer_instance *ti;
761 	unsigned long ticks = ~0UL;
762 
763 	list_for_each_entry(ti, &timer->active_list_head, active_list) {
764 		if (ti->flags & SNDRV_TIMER_IFLG_START) {
765 			ti->flags &= ~SNDRV_TIMER_IFLG_START;
766 			ti->flags |= SNDRV_TIMER_IFLG_RUNNING;
767 			timer->running++;
768 		}
769 		if (ti->flags & SNDRV_TIMER_IFLG_RUNNING) {
770 			if (ticks > ti->cticks)
771 				ticks = ti->cticks;
772 		}
773 	}
774 	if (ticks == ~0UL) {
775 		timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
776 		return;
777 	}
778 	if (ticks > timer->hw.ticks)
779 		ticks = timer->hw.ticks;
780 	if (ticks_left != ticks)
781 		timer->flags |= SNDRV_TIMER_FLG_CHANGE;
782 	timer->sticks = ticks;
783 }
784 
785 /* call callbacks in timer ack list */
snd_timer_process_callbacks(struct snd_timer * timer,struct list_head * head)786 static void snd_timer_process_callbacks(struct snd_timer *timer,
787 					struct list_head *head)
788 {
789 	struct snd_timer_instance *ti;
790 	unsigned long resolution, ticks;
791 
792 	while (!list_empty(head)) {
793 		ti = list_first_entry(head, struct snd_timer_instance,
794 				      ack_list);
795 
796 		/* remove from ack_list and make empty */
797 		list_del_init(&ti->ack_list);
798 
799 		if (!(ti->flags & SNDRV_TIMER_IFLG_DEAD)) {
800 			ticks = ti->pticks;
801 			ti->pticks = 0;
802 			resolution = ti->resolution;
803 			ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
804 			spin_unlock(&timer->lock);
805 			if (ti->callback)
806 				ti->callback(ti, resolution, ticks);
807 			spin_lock(&timer->lock);
808 			ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
809 		}
810 	}
811 }
812 
813 /* clear pending instances from ack list */
snd_timer_clear_callbacks(struct snd_timer * timer,struct list_head * head)814 static void snd_timer_clear_callbacks(struct snd_timer *timer,
815 				      struct list_head *head)
816 {
817 	unsigned long flags;
818 
819 	spin_lock_irqsave(&timer->lock, flags);
820 	while (!list_empty(head))
821 		list_del_init(head->next);
822 	spin_unlock_irqrestore(&timer->lock, flags);
823 }
824 
825 /*
826  * timer work
827  *
828  */
snd_timer_work(struct work_struct * work)829 static void snd_timer_work(struct work_struct *work)
830 {
831 	struct snd_timer *timer = container_of(work, struct snd_timer, task_work);
832 	unsigned long flags;
833 
834 	if (timer->card && timer->card->shutdown) {
835 		snd_timer_clear_callbacks(timer, &timer->sack_list_head);
836 		return;
837 	}
838 
839 	spin_lock_irqsave(&timer->lock, flags);
840 	snd_timer_process_callbacks(timer, &timer->sack_list_head);
841 	spin_unlock_irqrestore(&timer->lock, flags);
842 }
843 
844 /*
845  * timer interrupt
846  *
847  * ticks_left is usually equal to timer->sticks.
848  *
849  */
snd_timer_interrupt(struct snd_timer * timer,unsigned long ticks_left)850 void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
851 {
852 	struct snd_timer_instance *ti, *ts, *tmp;
853 	unsigned long resolution;
854 	struct list_head *ack_list_head;
855 	unsigned long flags;
856 	bool use_work = false;
857 
858 	if (timer == NULL)
859 		return;
860 
861 	if (timer->card && timer->card->shutdown) {
862 		snd_timer_clear_callbacks(timer, &timer->ack_list_head);
863 		return;
864 	}
865 
866 	spin_lock_irqsave(&timer->lock, flags);
867 
868 	/* remember the current resolution */
869 	resolution = snd_timer_hw_resolution(timer);
870 
871 	/* loop for all active instances
872 	 * Here we cannot use list_for_each_entry because the active_list of a
873 	 * processed instance is relinked to done_list_head before the callback
874 	 * is called.
875 	 */
876 	list_for_each_entry_safe(ti, tmp, &timer->active_list_head,
877 				 active_list) {
878 		if (ti->flags & SNDRV_TIMER_IFLG_DEAD)
879 			continue;
880 		if (!(ti->flags & SNDRV_TIMER_IFLG_RUNNING))
881 			continue;
882 		ti->pticks += ticks_left;
883 		ti->resolution = resolution;
884 		if (ti->cticks < ticks_left)
885 			ti->cticks = 0;
886 		else
887 			ti->cticks -= ticks_left;
888 		if (ti->cticks) /* not expired */
889 			continue;
890 		if (ti->flags & SNDRV_TIMER_IFLG_AUTO) {
891 			ti->cticks = ti->ticks;
892 		} else {
893 			ti->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
894 			--timer->running;
895 			list_del_init(&ti->active_list);
896 		}
897 		if ((timer->hw.flags & SNDRV_TIMER_HW_WORK) ||
898 		    (ti->flags & SNDRV_TIMER_IFLG_FAST))
899 			ack_list_head = &timer->ack_list_head;
900 		else
901 			ack_list_head = &timer->sack_list_head;
902 		if (list_empty(&ti->ack_list))
903 			list_add_tail(&ti->ack_list, ack_list_head);
904 		list_for_each_entry(ts, &ti->slave_active_head, active_list) {
905 			ts->pticks = ti->pticks;
906 			ts->resolution = resolution;
907 			if (list_empty(&ts->ack_list))
908 				list_add_tail(&ts->ack_list, ack_list_head);
909 		}
910 	}
911 	if (timer->flags & SNDRV_TIMER_FLG_RESCHED)
912 		snd_timer_reschedule(timer, timer->sticks);
913 	if (timer->running) {
914 		if (timer->hw.flags & SNDRV_TIMER_HW_STOP) {
915 			timer->hw.stop(timer);
916 			timer->flags |= SNDRV_TIMER_FLG_CHANGE;
917 		}
918 		if (!(timer->hw.flags & SNDRV_TIMER_HW_AUTO) ||
919 		    (timer->flags & SNDRV_TIMER_FLG_CHANGE)) {
920 			/* restart timer */
921 			timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
922 			timer->hw.start(timer);
923 		}
924 	} else {
925 		timer->hw.stop(timer);
926 	}
927 
928 	/* now process all fast callbacks */
929 	snd_timer_process_callbacks(timer, &timer->ack_list_head);
930 
931 	/* do we have any slow callbacks? */
932 	use_work = !list_empty(&timer->sack_list_head);
933 	spin_unlock_irqrestore(&timer->lock, flags);
934 
935 	if (use_work)
936 		queue_work(system_highpri_wq, &timer->task_work);
937 }
938 EXPORT_SYMBOL(snd_timer_interrupt);
939 
940 /*
941 
942  */
943 
snd_timer_new(struct snd_card * card,char * id,struct snd_timer_id * tid,struct snd_timer ** rtimer)944 int snd_timer_new(struct snd_card *card, char *id, struct snd_timer_id *tid,
945 		  struct snd_timer **rtimer)
946 {
947 	struct snd_timer *timer;
948 	int err;
949 	static const struct snd_device_ops ops = {
950 		.dev_free = snd_timer_dev_free,
951 		.dev_register = snd_timer_dev_register,
952 		.dev_disconnect = snd_timer_dev_disconnect,
953 	};
954 
955 	if (snd_BUG_ON(!tid))
956 		return -EINVAL;
957 	if (tid->dev_class == SNDRV_TIMER_CLASS_CARD ||
958 	    tid->dev_class == SNDRV_TIMER_CLASS_PCM) {
959 		if (WARN_ON(!card))
960 			return -EINVAL;
961 	}
962 	if (rtimer)
963 		*rtimer = NULL;
964 	timer = kzalloc(sizeof(*timer), GFP_KERNEL);
965 	if (!timer)
966 		return -ENOMEM;
967 	timer->tmr_class = tid->dev_class;
968 	timer->card = card;
969 	timer->tmr_device = tid->device;
970 	timer->tmr_subdevice = tid->subdevice;
971 	if (id)
972 		strscpy(timer->id, id, sizeof(timer->id));
973 	timer->sticks = 1;
974 	INIT_LIST_HEAD(&timer->device_list);
975 	INIT_LIST_HEAD(&timer->open_list_head);
976 	INIT_LIST_HEAD(&timer->active_list_head);
977 	INIT_LIST_HEAD(&timer->ack_list_head);
978 	INIT_LIST_HEAD(&timer->sack_list_head);
979 	spin_lock_init(&timer->lock);
980 	INIT_WORK(&timer->task_work, snd_timer_work);
981 	timer->max_instances = 1000; /* default limit per timer */
982 	if (card != NULL) {
983 		timer->module = card->module;
984 		err = snd_device_new(card, SNDRV_DEV_TIMER, timer, &ops);
985 		if (err < 0) {
986 			snd_timer_free(timer);
987 			return err;
988 		}
989 	}
990 	if (rtimer)
991 		*rtimer = timer;
992 	return 0;
993 }
994 EXPORT_SYMBOL(snd_timer_new);
995 
snd_timer_free(struct snd_timer * timer)996 static int snd_timer_free(struct snd_timer *timer)
997 {
998 	if (!timer)
999 		return 0;
1000 
1001 	mutex_lock(&register_mutex);
1002 	if (! list_empty(&timer->open_list_head)) {
1003 		struct list_head *p, *n;
1004 		struct snd_timer_instance *ti;
1005 		pr_warn("ALSA: timer %p is busy?\n", timer);
1006 		list_for_each_safe(p, n, &timer->open_list_head) {
1007 			list_del_init(p);
1008 			ti = list_entry(p, struct snd_timer_instance, open_list);
1009 			ti->timer = NULL;
1010 		}
1011 	}
1012 	list_del(&timer->device_list);
1013 	mutex_unlock(&register_mutex);
1014 
1015 	if (timer->private_free)
1016 		timer->private_free(timer);
1017 	kfree(timer);
1018 	return 0;
1019 }
1020 
snd_timer_dev_free(struct snd_device * device)1021 static int snd_timer_dev_free(struct snd_device *device)
1022 {
1023 	struct snd_timer *timer = device->device_data;
1024 	return snd_timer_free(timer);
1025 }
1026 
snd_timer_dev_register(struct snd_device * dev)1027 static int snd_timer_dev_register(struct snd_device *dev)
1028 {
1029 	struct snd_timer *timer = dev->device_data;
1030 	struct snd_timer *timer1;
1031 
1032 	if (snd_BUG_ON(!timer || !timer->hw.start || !timer->hw.stop))
1033 		return -ENXIO;
1034 	if (!(timer->hw.flags & SNDRV_TIMER_HW_SLAVE) &&
1035 	    !timer->hw.resolution && timer->hw.c_resolution == NULL)
1036 	    	return -EINVAL;
1037 
1038 	mutex_lock(&register_mutex);
1039 	list_for_each_entry(timer1, &snd_timer_list, device_list) {
1040 		if (timer1->tmr_class > timer->tmr_class)
1041 			break;
1042 		if (timer1->tmr_class < timer->tmr_class)
1043 			continue;
1044 		if (timer1->card && timer->card) {
1045 			if (timer1->card->number > timer->card->number)
1046 				break;
1047 			if (timer1->card->number < timer->card->number)
1048 				continue;
1049 		}
1050 		if (timer1->tmr_device > timer->tmr_device)
1051 			break;
1052 		if (timer1->tmr_device < timer->tmr_device)
1053 			continue;
1054 		if (timer1->tmr_subdevice > timer->tmr_subdevice)
1055 			break;
1056 		if (timer1->tmr_subdevice < timer->tmr_subdevice)
1057 			continue;
1058 		/* conflicts.. */
1059 		mutex_unlock(&register_mutex);
1060 		return -EBUSY;
1061 	}
1062 	list_add_tail(&timer->device_list, &timer1->device_list);
1063 	mutex_unlock(&register_mutex);
1064 	return 0;
1065 }
1066 
snd_timer_dev_disconnect(struct snd_device * device)1067 static int snd_timer_dev_disconnect(struct snd_device *device)
1068 {
1069 	struct snd_timer *timer = device->device_data;
1070 	struct snd_timer_instance *ti;
1071 
1072 	mutex_lock(&register_mutex);
1073 	list_del_init(&timer->device_list);
1074 	/* wake up pending sleepers */
1075 	list_for_each_entry(ti, &timer->open_list_head, open_list) {
1076 		if (ti->disconnect)
1077 			ti->disconnect(ti);
1078 	}
1079 	mutex_unlock(&register_mutex);
1080 	return 0;
1081 }
1082 
snd_timer_notify(struct snd_timer * timer,int event,struct timespec64 * tstamp)1083 void snd_timer_notify(struct snd_timer *timer, int event, struct timespec64 *tstamp)
1084 {
1085 	unsigned long flags;
1086 	unsigned long resolution = 0;
1087 	struct snd_timer_instance *ti, *ts;
1088 
1089 	if (timer->card && timer->card->shutdown)
1090 		return;
1091 	if (! (timer->hw.flags & SNDRV_TIMER_HW_SLAVE))
1092 		return;
1093 	if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_MSTART ||
1094 		       event > SNDRV_TIMER_EVENT_MRESUME))
1095 		return;
1096 	spin_lock_irqsave(&timer->lock, flags);
1097 	if (event == SNDRV_TIMER_EVENT_MSTART ||
1098 	    event == SNDRV_TIMER_EVENT_MCONTINUE ||
1099 	    event == SNDRV_TIMER_EVENT_MRESUME)
1100 		resolution = snd_timer_hw_resolution(timer);
1101 	list_for_each_entry(ti, &timer->active_list_head, active_list) {
1102 		if (ti->ccallback)
1103 			ti->ccallback(ti, event, tstamp, resolution);
1104 		list_for_each_entry(ts, &ti->slave_active_head, active_list)
1105 			if (ts->ccallback)
1106 				ts->ccallback(ts, event, tstamp, resolution);
1107 	}
1108 	spin_unlock_irqrestore(&timer->lock, flags);
1109 }
1110 EXPORT_SYMBOL(snd_timer_notify);
1111 
1112 /*
1113  * exported functions for global timers
1114  */
snd_timer_global_new(char * id,int device,struct snd_timer ** rtimer)1115 int snd_timer_global_new(char *id, int device, struct snd_timer **rtimer)
1116 {
1117 	struct snd_timer_id tid;
1118 
1119 	tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
1120 	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1121 	tid.card = -1;
1122 	tid.device = device;
1123 	tid.subdevice = 0;
1124 	return snd_timer_new(NULL, id, &tid, rtimer);
1125 }
1126 EXPORT_SYMBOL(snd_timer_global_new);
1127 
snd_timer_global_free(struct snd_timer * timer)1128 int snd_timer_global_free(struct snd_timer *timer)
1129 {
1130 	return snd_timer_free(timer);
1131 }
1132 EXPORT_SYMBOL(snd_timer_global_free);
1133 
snd_timer_global_register(struct snd_timer * timer)1134 int snd_timer_global_register(struct snd_timer *timer)
1135 {
1136 	struct snd_device dev;
1137 
1138 	memset(&dev, 0, sizeof(dev));
1139 	dev.device_data = timer;
1140 	return snd_timer_dev_register(&dev);
1141 }
1142 EXPORT_SYMBOL(snd_timer_global_register);
1143 
1144 /*
1145  *  System timer
1146  */
1147 
1148 struct snd_timer_system_private {
1149 	struct timer_list tlist;
1150 	struct snd_timer *snd_timer;
1151 	unsigned long last_expires;
1152 	unsigned long last_jiffies;
1153 	unsigned long correction;
1154 };
1155 
snd_timer_s_function(struct timer_list * t)1156 static void snd_timer_s_function(struct timer_list *t)
1157 {
1158 	struct snd_timer_system_private *priv = from_timer(priv, t,
1159 								tlist);
1160 	struct snd_timer *timer = priv->snd_timer;
1161 	unsigned long jiff = jiffies;
1162 	if (time_after(jiff, priv->last_expires))
1163 		priv->correction += (long)jiff - (long)priv->last_expires;
1164 	snd_timer_interrupt(timer, (long)jiff - (long)priv->last_jiffies);
1165 }
1166 
snd_timer_s_start(struct snd_timer * timer)1167 static int snd_timer_s_start(struct snd_timer * timer)
1168 {
1169 	struct snd_timer_system_private *priv;
1170 	unsigned long njiff;
1171 
1172 	priv = (struct snd_timer_system_private *) timer->private_data;
1173 	njiff = (priv->last_jiffies = jiffies);
1174 	if (priv->correction > timer->sticks - 1) {
1175 		priv->correction -= timer->sticks - 1;
1176 		njiff++;
1177 	} else {
1178 		njiff += timer->sticks - priv->correction;
1179 		priv->correction = 0;
1180 	}
1181 	priv->last_expires = njiff;
1182 	mod_timer(&priv->tlist, njiff);
1183 	return 0;
1184 }
1185 
snd_timer_s_stop(struct snd_timer * timer)1186 static int snd_timer_s_stop(struct snd_timer * timer)
1187 {
1188 	struct snd_timer_system_private *priv;
1189 	unsigned long jiff;
1190 
1191 	priv = (struct snd_timer_system_private *) timer->private_data;
1192 	del_timer(&priv->tlist);
1193 	jiff = jiffies;
1194 	if (time_before(jiff, priv->last_expires))
1195 		timer->sticks = priv->last_expires - jiff;
1196 	else
1197 		timer->sticks = 1;
1198 	priv->correction = 0;
1199 	return 0;
1200 }
1201 
snd_timer_s_close(struct snd_timer * timer)1202 static int snd_timer_s_close(struct snd_timer *timer)
1203 {
1204 	struct snd_timer_system_private *priv;
1205 
1206 	priv = (struct snd_timer_system_private *)timer->private_data;
1207 	del_timer_sync(&priv->tlist);
1208 	return 0;
1209 }
1210 
1211 static const struct snd_timer_hardware snd_timer_system =
1212 {
1213 	.flags =	SNDRV_TIMER_HW_FIRST | SNDRV_TIMER_HW_WORK,
1214 	.resolution =	1000000000L / HZ,
1215 	.ticks =	10000000L,
1216 	.close =	snd_timer_s_close,
1217 	.start =	snd_timer_s_start,
1218 	.stop =		snd_timer_s_stop
1219 };
1220 
snd_timer_free_system(struct snd_timer * timer)1221 static void snd_timer_free_system(struct snd_timer *timer)
1222 {
1223 	kfree(timer->private_data);
1224 }
1225 
snd_timer_register_system(void)1226 static int snd_timer_register_system(void)
1227 {
1228 	struct snd_timer *timer;
1229 	struct snd_timer_system_private *priv;
1230 	int err;
1231 
1232 	err = snd_timer_global_new("system", SNDRV_TIMER_GLOBAL_SYSTEM, &timer);
1233 	if (err < 0)
1234 		return err;
1235 	strcpy(timer->name, "system timer");
1236 	timer->hw = snd_timer_system;
1237 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1238 	if (priv == NULL) {
1239 		snd_timer_free(timer);
1240 		return -ENOMEM;
1241 	}
1242 	priv->snd_timer = timer;
1243 	timer_setup(&priv->tlist, snd_timer_s_function, 0);
1244 	timer->private_data = priv;
1245 	timer->private_free = snd_timer_free_system;
1246 	return snd_timer_global_register(timer);
1247 }
1248 
1249 #ifdef CONFIG_SND_PROC_FS
1250 /*
1251  *  Info interface
1252  */
1253 
snd_timer_proc_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)1254 static void snd_timer_proc_read(struct snd_info_entry *entry,
1255 				struct snd_info_buffer *buffer)
1256 {
1257 	struct snd_timer *timer;
1258 	struct snd_timer_instance *ti;
1259 	unsigned long resolution;
1260 
1261 	mutex_lock(&register_mutex);
1262 	list_for_each_entry(timer, &snd_timer_list, device_list) {
1263 		if (timer->card && timer->card->shutdown)
1264 			continue;
1265 		switch (timer->tmr_class) {
1266 		case SNDRV_TIMER_CLASS_GLOBAL:
1267 			snd_iprintf(buffer, "G%i: ", timer->tmr_device);
1268 			break;
1269 		case SNDRV_TIMER_CLASS_CARD:
1270 			snd_iprintf(buffer, "C%i-%i: ",
1271 				    timer->card->number, timer->tmr_device);
1272 			break;
1273 		case SNDRV_TIMER_CLASS_PCM:
1274 			snd_iprintf(buffer, "P%i-%i-%i: ", timer->card->number,
1275 				    timer->tmr_device, timer->tmr_subdevice);
1276 			break;
1277 		default:
1278 			snd_iprintf(buffer, "?%i-%i-%i-%i: ", timer->tmr_class,
1279 				    timer->card ? timer->card->number : -1,
1280 				    timer->tmr_device, timer->tmr_subdevice);
1281 		}
1282 		snd_iprintf(buffer, "%s :", timer->name);
1283 		spin_lock_irq(&timer->lock);
1284 		resolution = snd_timer_hw_resolution(timer);
1285 		spin_unlock_irq(&timer->lock);
1286 		if (resolution)
1287 			snd_iprintf(buffer, " %lu.%03luus (%lu ticks)",
1288 				    resolution / 1000,
1289 				    resolution % 1000,
1290 				    timer->hw.ticks);
1291 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
1292 			snd_iprintf(buffer, " SLAVE");
1293 		snd_iprintf(buffer, "\n");
1294 		list_for_each_entry(ti, &timer->open_list_head, open_list)
1295 			snd_iprintf(buffer, "  Client %s : %s\n",
1296 				    ti->owner ? ti->owner : "unknown",
1297 				    (ti->flags & (SNDRV_TIMER_IFLG_START |
1298 						  SNDRV_TIMER_IFLG_RUNNING))
1299 				    ? "running" : "stopped");
1300 	}
1301 	mutex_unlock(&register_mutex);
1302 }
1303 
1304 static struct snd_info_entry *snd_timer_proc_entry;
1305 
snd_timer_proc_init(void)1306 static void __init snd_timer_proc_init(void)
1307 {
1308 	struct snd_info_entry *entry;
1309 
1310 	entry = snd_info_create_module_entry(THIS_MODULE, "timers", NULL);
1311 	if (entry != NULL) {
1312 		entry->c.text.read = snd_timer_proc_read;
1313 		if (snd_info_register(entry) < 0) {
1314 			snd_info_free_entry(entry);
1315 			entry = NULL;
1316 		}
1317 	}
1318 	snd_timer_proc_entry = entry;
1319 }
1320 
snd_timer_proc_done(void)1321 static void __exit snd_timer_proc_done(void)
1322 {
1323 	snd_info_free_entry(snd_timer_proc_entry);
1324 }
1325 #else /* !CONFIG_SND_PROC_FS */
1326 #define snd_timer_proc_init()
1327 #define snd_timer_proc_done()
1328 #endif
1329 
1330 /*
1331  *  USER SPACE interface
1332  */
1333 
snd_timer_user_interrupt(struct snd_timer_instance * timeri,unsigned long resolution,unsigned long ticks)1334 static void snd_timer_user_interrupt(struct snd_timer_instance *timeri,
1335 				     unsigned long resolution,
1336 				     unsigned long ticks)
1337 {
1338 	struct snd_timer_user *tu = timeri->callback_data;
1339 	struct snd_timer_read *r;
1340 	int prev;
1341 
1342 	spin_lock(&tu->qlock);
1343 	if (tu->qused > 0) {
1344 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1345 		r = &tu->queue[prev];
1346 		if (r->resolution == resolution) {
1347 			r->ticks += ticks;
1348 			goto __wake;
1349 		}
1350 	}
1351 	if (tu->qused >= tu->queue_size) {
1352 		tu->overrun++;
1353 	} else {
1354 		r = &tu->queue[tu->qtail++];
1355 		tu->qtail %= tu->queue_size;
1356 		r->resolution = resolution;
1357 		r->ticks = ticks;
1358 		tu->qused++;
1359 	}
1360       __wake:
1361 	spin_unlock(&tu->qlock);
1362 	snd_kill_fasync(tu->fasync, SIGIO, POLL_IN);
1363 	wake_up(&tu->qchange_sleep);
1364 }
1365 
snd_timer_user_append_to_tqueue(struct snd_timer_user * tu,struct snd_timer_tread64 * tread)1366 static void snd_timer_user_append_to_tqueue(struct snd_timer_user *tu,
1367 					    struct snd_timer_tread64 *tread)
1368 {
1369 	if (tu->qused >= tu->queue_size) {
1370 		tu->overrun++;
1371 	} else {
1372 		memcpy(&tu->tqueue[tu->qtail++], tread, sizeof(*tread));
1373 		tu->qtail %= tu->queue_size;
1374 		tu->qused++;
1375 	}
1376 }
1377 
snd_timer_user_ccallback(struct snd_timer_instance * timeri,int event,struct timespec64 * tstamp,unsigned long resolution)1378 static void snd_timer_user_ccallback(struct snd_timer_instance *timeri,
1379 				     int event,
1380 				     struct timespec64 *tstamp,
1381 				     unsigned long resolution)
1382 {
1383 	struct snd_timer_user *tu = timeri->callback_data;
1384 	struct snd_timer_tread64 r1;
1385 	unsigned long flags;
1386 
1387 	if (event >= SNDRV_TIMER_EVENT_START &&
1388 	    event <= SNDRV_TIMER_EVENT_PAUSE)
1389 		tu->tstamp = *tstamp;
1390 	if ((tu->filter & (1 << event)) == 0 || !tu->tread)
1391 		return;
1392 	memset(&r1, 0, sizeof(r1));
1393 	r1.event = event;
1394 	r1.tstamp_sec = tstamp->tv_sec;
1395 	r1.tstamp_nsec = tstamp->tv_nsec;
1396 	r1.val = resolution;
1397 	spin_lock_irqsave(&tu->qlock, flags);
1398 	snd_timer_user_append_to_tqueue(tu, &r1);
1399 	spin_unlock_irqrestore(&tu->qlock, flags);
1400 	snd_kill_fasync(tu->fasync, SIGIO, POLL_IN);
1401 	wake_up(&tu->qchange_sleep);
1402 }
1403 
snd_timer_user_disconnect(struct snd_timer_instance * timeri)1404 static void snd_timer_user_disconnect(struct snd_timer_instance *timeri)
1405 {
1406 	struct snd_timer_user *tu = timeri->callback_data;
1407 
1408 	tu->disconnected = true;
1409 	wake_up(&tu->qchange_sleep);
1410 }
1411 
snd_timer_user_tinterrupt(struct snd_timer_instance * timeri,unsigned long resolution,unsigned long ticks)1412 static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
1413 				      unsigned long resolution,
1414 				      unsigned long ticks)
1415 {
1416 	struct snd_timer_user *tu = timeri->callback_data;
1417 	struct snd_timer_tread64 *r, r1;
1418 	struct timespec64 tstamp;
1419 	int prev, append = 0;
1420 
1421 	memset(&r1, 0, sizeof(r1));
1422 	memset(&tstamp, 0, sizeof(tstamp));
1423 	spin_lock(&tu->qlock);
1424 	if ((tu->filter & ((1 << SNDRV_TIMER_EVENT_RESOLUTION) |
1425 			   (1 << SNDRV_TIMER_EVENT_TICK))) == 0) {
1426 		spin_unlock(&tu->qlock);
1427 		return;
1428 	}
1429 	if (tu->last_resolution != resolution || ticks > 0) {
1430 		if (timer_tstamp_monotonic)
1431 			ktime_get_ts64(&tstamp);
1432 		else
1433 			ktime_get_real_ts64(&tstamp);
1434 	}
1435 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_RESOLUTION)) &&
1436 	    tu->last_resolution != resolution) {
1437 		r1.event = SNDRV_TIMER_EVENT_RESOLUTION;
1438 		r1.tstamp_sec = tstamp.tv_sec;
1439 		r1.tstamp_nsec = tstamp.tv_nsec;
1440 		r1.val = resolution;
1441 		snd_timer_user_append_to_tqueue(tu, &r1);
1442 		tu->last_resolution = resolution;
1443 		append++;
1444 	}
1445 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_TICK)) == 0)
1446 		goto __wake;
1447 	if (ticks == 0)
1448 		goto __wake;
1449 	if (tu->qused > 0) {
1450 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1451 		r = &tu->tqueue[prev];
1452 		if (r->event == SNDRV_TIMER_EVENT_TICK) {
1453 			r->tstamp_sec = tstamp.tv_sec;
1454 			r->tstamp_nsec = tstamp.tv_nsec;
1455 			r->val += ticks;
1456 			append++;
1457 			goto __wake;
1458 		}
1459 	}
1460 	r1.event = SNDRV_TIMER_EVENT_TICK;
1461 	r1.tstamp_sec = tstamp.tv_sec;
1462 	r1.tstamp_nsec = tstamp.tv_nsec;
1463 	r1.val = ticks;
1464 	snd_timer_user_append_to_tqueue(tu, &r1);
1465 	append++;
1466       __wake:
1467 	spin_unlock(&tu->qlock);
1468 	if (append == 0)
1469 		return;
1470 	snd_kill_fasync(tu->fasync, SIGIO, POLL_IN);
1471 	wake_up(&tu->qchange_sleep);
1472 }
1473 
realloc_user_queue(struct snd_timer_user * tu,int size)1474 static int realloc_user_queue(struct snd_timer_user *tu, int size)
1475 {
1476 	struct snd_timer_read *queue = NULL;
1477 	struct snd_timer_tread64 *tqueue = NULL;
1478 
1479 	if (tu->tread) {
1480 		tqueue = kcalloc(size, sizeof(*tqueue), GFP_KERNEL);
1481 		if (!tqueue)
1482 			return -ENOMEM;
1483 	} else {
1484 		queue = kcalloc(size, sizeof(*queue), GFP_KERNEL);
1485 		if (!queue)
1486 			return -ENOMEM;
1487 	}
1488 
1489 	spin_lock_irq(&tu->qlock);
1490 	kfree(tu->queue);
1491 	kfree(tu->tqueue);
1492 	tu->queue_size = size;
1493 	tu->queue = queue;
1494 	tu->tqueue = tqueue;
1495 	tu->qhead = tu->qtail = tu->qused = 0;
1496 	spin_unlock_irq(&tu->qlock);
1497 
1498 	return 0;
1499 }
1500 
snd_timer_user_open(struct inode * inode,struct file * file)1501 static int snd_timer_user_open(struct inode *inode, struct file *file)
1502 {
1503 	struct snd_timer_user *tu;
1504 	int err;
1505 
1506 	err = stream_open(inode, file);
1507 	if (err < 0)
1508 		return err;
1509 
1510 	tu = kzalloc(sizeof(*tu), GFP_KERNEL);
1511 	if (tu == NULL)
1512 		return -ENOMEM;
1513 	spin_lock_init(&tu->qlock);
1514 	init_waitqueue_head(&tu->qchange_sleep);
1515 	mutex_init(&tu->ioctl_lock);
1516 	tu->ticks = 1;
1517 	if (realloc_user_queue(tu, 128) < 0) {
1518 		kfree(tu);
1519 		return -ENOMEM;
1520 	}
1521 	file->private_data = tu;
1522 	return 0;
1523 }
1524 
snd_timer_user_release(struct inode * inode,struct file * file)1525 static int snd_timer_user_release(struct inode *inode, struct file *file)
1526 {
1527 	struct snd_timer_user *tu;
1528 
1529 	if (file->private_data) {
1530 		tu = file->private_data;
1531 		file->private_data = NULL;
1532 		mutex_lock(&tu->ioctl_lock);
1533 		if (tu->timeri) {
1534 			snd_timer_close(tu->timeri);
1535 			snd_timer_instance_free(tu->timeri);
1536 		}
1537 		mutex_unlock(&tu->ioctl_lock);
1538 		snd_fasync_free(tu->fasync);
1539 		kfree(tu->queue);
1540 		kfree(tu->tqueue);
1541 		kfree(tu);
1542 	}
1543 	return 0;
1544 }
1545 
snd_timer_user_zero_id(struct snd_timer_id * id)1546 static void snd_timer_user_zero_id(struct snd_timer_id *id)
1547 {
1548 	id->dev_class = SNDRV_TIMER_CLASS_NONE;
1549 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1550 	id->card = -1;
1551 	id->device = -1;
1552 	id->subdevice = -1;
1553 }
1554 
snd_timer_user_copy_id(struct snd_timer_id * id,struct snd_timer * timer)1555 static void snd_timer_user_copy_id(struct snd_timer_id *id, struct snd_timer *timer)
1556 {
1557 	id->dev_class = timer->tmr_class;
1558 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1559 	id->card = timer->card ? timer->card->number : -1;
1560 	id->device = timer->tmr_device;
1561 	id->subdevice = timer->tmr_subdevice;
1562 }
1563 
snd_timer_user_next_device(struct snd_timer_id __user * _tid)1564 static int snd_timer_user_next_device(struct snd_timer_id __user *_tid)
1565 {
1566 	struct snd_timer_id id;
1567 	struct snd_timer *timer;
1568 	struct list_head *p;
1569 
1570 	if (copy_from_user(&id, _tid, sizeof(id)))
1571 		return -EFAULT;
1572 	mutex_lock(&register_mutex);
1573 	if (id.dev_class < 0) {		/* first item */
1574 		if (list_empty(&snd_timer_list))
1575 			snd_timer_user_zero_id(&id);
1576 		else {
1577 			timer = list_entry(snd_timer_list.next,
1578 					   struct snd_timer, device_list);
1579 			snd_timer_user_copy_id(&id, timer);
1580 		}
1581 	} else {
1582 		switch (id.dev_class) {
1583 		case SNDRV_TIMER_CLASS_GLOBAL:
1584 			id.device = id.device < 0 ? 0 : id.device + 1;
1585 			list_for_each(p, &snd_timer_list) {
1586 				timer = list_entry(p, struct snd_timer, device_list);
1587 				if (timer->tmr_class > SNDRV_TIMER_CLASS_GLOBAL) {
1588 					snd_timer_user_copy_id(&id, timer);
1589 					break;
1590 				}
1591 				if (timer->tmr_device >= id.device) {
1592 					snd_timer_user_copy_id(&id, timer);
1593 					break;
1594 				}
1595 			}
1596 			if (p == &snd_timer_list)
1597 				snd_timer_user_zero_id(&id);
1598 			break;
1599 		case SNDRV_TIMER_CLASS_CARD:
1600 		case SNDRV_TIMER_CLASS_PCM:
1601 			if (id.card < 0) {
1602 				id.card = 0;
1603 			} else {
1604 				if (id.device < 0) {
1605 					id.device = 0;
1606 				} else {
1607 					if (id.subdevice < 0)
1608 						id.subdevice = 0;
1609 					else if (id.subdevice < INT_MAX)
1610 						id.subdevice++;
1611 				}
1612 			}
1613 			list_for_each(p, &snd_timer_list) {
1614 				timer = list_entry(p, struct snd_timer, device_list);
1615 				if (timer->tmr_class > id.dev_class) {
1616 					snd_timer_user_copy_id(&id, timer);
1617 					break;
1618 				}
1619 				if (timer->tmr_class < id.dev_class)
1620 					continue;
1621 				if (timer->card->number > id.card) {
1622 					snd_timer_user_copy_id(&id, timer);
1623 					break;
1624 				}
1625 				if (timer->card->number < id.card)
1626 					continue;
1627 				if (timer->tmr_device > id.device) {
1628 					snd_timer_user_copy_id(&id, timer);
1629 					break;
1630 				}
1631 				if (timer->tmr_device < id.device)
1632 					continue;
1633 				if (timer->tmr_subdevice > id.subdevice) {
1634 					snd_timer_user_copy_id(&id, timer);
1635 					break;
1636 				}
1637 				if (timer->tmr_subdevice < id.subdevice)
1638 					continue;
1639 				snd_timer_user_copy_id(&id, timer);
1640 				break;
1641 			}
1642 			if (p == &snd_timer_list)
1643 				snd_timer_user_zero_id(&id);
1644 			break;
1645 		default:
1646 			snd_timer_user_zero_id(&id);
1647 		}
1648 	}
1649 	mutex_unlock(&register_mutex);
1650 	if (copy_to_user(_tid, &id, sizeof(*_tid)))
1651 		return -EFAULT;
1652 	return 0;
1653 }
1654 
snd_timer_user_ginfo(struct file * file,struct snd_timer_ginfo __user * _ginfo)1655 static int snd_timer_user_ginfo(struct file *file,
1656 				struct snd_timer_ginfo __user *_ginfo)
1657 {
1658 	struct snd_timer_ginfo *ginfo;
1659 	struct snd_timer_id tid;
1660 	struct snd_timer *t;
1661 	struct list_head *p;
1662 	int err = 0;
1663 
1664 	ginfo = memdup_user(_ginfo, sizeof(*ginfo));
1665 	if (IS_ERR(ginfo))
1666 		return PTR_ERR(ginfo);
1667 
1668 	tid = ginfo->tid;
1669 	memset(ginfo, 0, sizeof(*ginfo));
1670 	ginfo->tid = tid;
1671 	mutex_lock(&register_mutex);
1672 	t = snd_timer_find(&tid);
1673 	if (t != NULL) {
1674 		ginfo->card = t->card ? t->card->number : -1;
1675 		if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1676 			ginfo->flags |= SNDRV_TIMER_FLG_SLAVE;
1677 		strscpy(ginfo->id, t->id, sizeof(ginfo->id));
1678 		strscpy(ginfo->name, t->name, sizeof(ginfo->name));
1679 		spin_lock_irq(&t->lock);
1680 		ginfo->resolution = snd_timer_hw_resolution(t);
1681 		spin_unlock_irq(&t->lock);
1682 		if (t->hw.resolution_min > 0) {
1683 			ginfo->resolution_min = t->hw.resolution_min;
1684 			ginfo->resolution_max = t->hw.resolution_max;
1685 		}
1686 		list_for_each(p, &t->open_list_head) {
1687 			ginfo->clients++;
1688 		}
1689 	} else {
1690 		err = -ENODEV;
1691 	}
1692 	mutex_unlock(&register_mutex);
1693 	if (err >= 0 && copy_to_user(_ginfo, ginfo, sizeof(*ginfo)))
1694 		err = -EFAULT;
1695 	kfree(ginfo);
1696 	return err;
1697 }
1698 
timer_set_gparams(struct snd_timer_gparams * gparams)1699 static int timer_set_gparams(struct snd_timer_gparams *gparams)
1700 {
1701 	struct snd_timer *t;
1702 	int err;
1703 
1704 	mutex_lock(&register_mutex);
1705 	t = snd_timer_find(&gparams->tid);
1706 	if (!t) {
1707 		err = -ENODEV;
1708 		goto _error;
1709 	}
1710 	if (!list_empty(&t->open_list_head)) {
1711 		err = -EBUSY;
1712 		goto _error;
1713 	}
1714 	if (!t->hw.set_period) {
1715 		err = -ENOSYS;
1716 		goto _error;
1717 	}
1718 	err = t->hw.set_period(t, gparams->period_num, gparams->period_den);
1719 _error:
1720 	mutex_unlock(&register_mutex);
1721 	return err;
1722 }
1723 
snd_timer_user_gparams(struct file * file,struct snd_timer_gparams __user * _gparams)1724 static int snd_timer_user_gparams(struct file *file,
1725 				  struct snd_timer_gparams __user *_gparams)
1726 {
1727 	struct snd_timer_gparams gparams;
1728 
1729 	if (copy_from_user(&gparams, _gparams, sizeof(gparams)))
1730 		return -EFAULT;
1731 	return timer_set_gparams(&gparams);
1732 }
1733 
snd_timer_user_gstatus(struct file * file,struct snd_timer_gstatus __user * _gstatus)1734 static int snd_timer_user_gstatus(struct file *file,
1735 				  struct snd_timer_gstatus __user *_gstatus)
1736 {
1737 	struct snd_timer_gstatus gstatus;
1738 	struct snd_timer_id tid;
1739 	struct snd_timer *t;
1740 	int err = 0;
1741 
1742 	if (copy_from_user(&gstatus, _gstatus, sizeof(gstatus)))
1743 		return -EFAULT;
1744 	tid = gstatus.tid;
1745 	memset(&gstatus, 0, sizeof(gstatus));
1746 	gstatus.tid = tid;
1747 	mutex_lock(&register_mutex);
1748 	t = snd_timer_find(&tid);
1749 	if (t != NULL) {
1750 		spin_lock_irq(&t->lock);
1751 		gstatus.resolution = snd_timer_hw_resolution(t);
1752 		if (t->hw.precise_resolution) {
1753 			t->hw.precise_resolution(t, &gstatus.resolution_num,
1754 						 &gstatus.resolution_den);
1755 		} else {
1756 			gstatus.resolution_num = gstatus.resolution;
1757 			gstatus.resolution_den = 1000000000uL;
1758 		}
1759 		spin_unlock_irq(&t->lock);
1760 	} else {
1761 		err = -ENODEV;
1762 	}
1763 	mutex_unlock(&register_mutex);
1764 	if (err >= 0 && copy_to_user(_gstatus, &gstatus, sizeof(gstatus)))
1765 		err = -EFAULT;
1766 	return err;
1767 }
1768 
snd_timer_user_tselect(struct file * file,struct snd_timer_select __user * _tselect)1769 static int snd_timer_user_tselect(struct file *file,
1770 				  struct snd_timer_select __user *_tselect)
1771 {
1772 	struct snd_timer_user *tu;
1773 	struct snd_timer_select tselect;
1774 	char str[32];
1775 	int err = 0;
1776 
1777 	tu = file->private_data;
1778 	if (tu->timeri) {
1779 		snd_timer_close(tu->timeri);
1780 		snd_timer_instance_free(tu->timeri);
1781 		tu->timeri = NULL;
1782 	}
1783 	if (copy_from_user(&tselect, _tselect, sizeof(tselect))) {
1784 		err = -EFAULT;
1785 		goto __err;
1786 	}
1787 	sprintf(str, "application %i", current->pid);
1788 	if (tselect.id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
1789 		tselect.id.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION;
1790 	tu->timeri = snd_timer_instance_new(str);
1791 	if (!tu->timeri) {
1792 		err = -ENOMEM;
1793 		goto __err;
1794 	}
1795 
1796 	tu->timeri->flags |= SNDRV_TIMER_IFLG_FAST;
1797 	tu->timeri->callback = tu->tread
1798 			? snd_timer_user_tinterrupt : snd_timer_user_interrupt;
1799 	tu->timeri->ccallback = snd_timer_user_ccallback;
1800 	tu->timeri->callback_data = (void *)tu;
1801 	tu->timeri->disconnect = snd_timer_user_disconnect;
1802 
1803 	err = snd_timer_open(tu->timeri, &tselect.id, current->pid);
1804 	if (err < 0) {
1805 		snd_timer_instance_free(tu->timeri);
1806 		tu->timeri = NULL;
1807 	}
1808 
1809       __err:
1810 	return err;
1811 }
1812 
snd_timer_user_info(struct file * file,struct snd_timer_info __user * _info)1813 static int snd_timer_user_info(struct file *file,
1814 			       struct snd_timer_info __user *_info)
1815 {
1816 	struct snd_timer_user *tu;
1817 	struct snd_timer_info *info;
1818 	struct snd_timer *t;
1819 	int err = 0;
1820 
1821 	tu = file->private_data;
1822 	if (!tu->timeri)
1823 		return -EBADFD;
1824 	t = tu->timeri->timer;
1825 	if (!t)
1826 		return -EBADFD;
1827 
1828 	info = kzalloc(sizeof(*info), GFP_KERNEL);
1829 	if (! info)
1830 		return -ENOMEM;
1831 	info->card = t->card ? t->card->number : -1;
1832 	if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1833 		info->flags |= SNDRV_TIMER_FLG_SLAVE;
1834 	strscpy(info->id, t->id, sizeof(info->id));
1835 	strscpy(info->name, t->name, sizeof(info->name));
1836 	spin_lock_irq(&t->lock);
1837 	info->resolution = snd_timer_hw_resolution(t);
1838 	spin_unlock_irq(&t->lock);
1839 	if (copy_to_user(_info, info, sizeof(*_info)))
1840 		err = -EFAULT;
1841 	kfree(info);
1842 	return err;
1843 }
1844 
snd_timer_user_params(struct file * file,struct snd_timer_params __user * _params)1845 static int snd_timer_user_params(struct file *file,
1846 				 struct snd_timer_params __user *_params)
1847 {
1848 	struct snd_timer_user *tu;
1849 	struct snd_timer_params params;
1850 	struct snd_timer *t;
1851 	int err;
1852 
1853 	tu = file->private_data;
1854 	if (!tu->timeri)
1855 		return -EBADFD;
1856 	t = tu->timeri->timer;
1857 	if (!t)
1858 		return -EBADFD;
1859 	if (copy_from_user(&params, _params, sizeof(params)))
1860 		return -EFAULT;
1861 	if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE)) {
1862 		u64 resolution;
1863 
1864 		if (params.ticks < 1) {
1865 			err = -EINVAL;
1866 			goto _end;
1867 		}
1868 
1869 		/* Don't allow resolution less than 1ms */
1870 		resolution = snd_timer_resolution(tu->timeri);
1871 		resolution *= params.ticks;
1872 		if (resolution < 1000000) {
1873 			err = -EINVAL;
1874 			goto _end;
1875 		}
1876 	}
1877 	if (params.queue_size > 0 &&
1878 	    (params.queue_size < 32 || params.queue_size > 1024)) {
1879 		err = -EINVAL;
1880 		goto _end;
1881 	}
1882 	if (params.filter & ~((1<<SNDRV_TIMER_EVENT_RESOLUTION)|
1883 			      (1<<SNDRV_TIMER_EVENT_TICK)|
1884 			      (1<<SNDRV_TIMER_EVENT_START)|
1885 			      (1<<SNDRV_TIMER_EVENT_STOP)|
1886 			      (1<<SNDRV_TIMER_EVENT_CONTINUE)|
1887 			      (1<<SNDRV_TIMER_EVENT_PAUSE)|
1888 			      (1<<SNDRV_TIMER_EVENT_SUSPEND)|
1889 			      (1<<SNDRV_TIMER_EVENT_RESUME)|
1890 			      (1<<SNDRV_TIMER_EVENT_MSTART)|
1891 			      (1<<SNDRV_TIMER_EVENT_MSTOP)|
1892 			      (1<<SNDRV_TIMER_EVENT_MCONTINUE)|
1893 			      (1<<SNDRV_TIMER_EVENT_MPAUSE)|
1894 			      (1<<SNDRV_TIMER_EVENT_MSUSPEND)|
1895 			      (1<<SNDRV_TIMER_EVENT_MRESUME))) {
1896 		err = -EINVAL;
1897 		goto _end;
1898 	}
1899 	snd_timer_stop(tu->timeri);
1900 	spin_lock_irq(&t->lock);
1901 	tu->timeri->flags &= ~(SNDRV_TIMER_IFLG_AUTO|
1902 			       SNDRV_TIMER_IFLG_EXCLUSIVE|
1903 			       SNDRV_TIMER_IFLG_EARLY_EVENT);
1904 	if (params.flags & SNDRV_TIMER_PSFLG_AUTO)
1905 		tu->timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1906 	if (params.flags & SNDRV_TIMER_PSFLG_EXCLUSIVE)
1907 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EXCLUSIVE;
1908 	if (params.flags & SNDRV_TIMER_PSFLG_EARLY_EVENT)
1909 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EARLY_EVENT;
1910 	spin_unlock_irq(&t->lock);
1911 	if (params.queue_size > 0 &&
1912 	    (unsigned int)tu->queue_size != params.queue_size) {
1913 		err = realloc_user_queue(tu, params.queue_size);
1914 		if (err < 0)
1915 			goto _end;
1916 	}
1917 	spin_lock_irq(&tu->qlock);
1918 	tu->qhead = tu->qtail = tu->qused = 0;
1919 	if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
1920 		if (tu->tread) {
1921 			struct snd_timer_tread64 tread;
1922 			memset(&tread, 0, sizeof(tread));
1923 			tread.event = SNDRV_TIMER_EVENT_EARLY;
1924 			tread.tstamp_sec = 0;
1925 			tread.tstamp_nsec = 0;
1926 			tread.val = 0;
1927 			snd_timer_user_append_to_tqueue(tu, &tread);
1928 		} else {
1929 			struct snd_timer_read *r = &tu->queue[0];
1930 			r->resolution = 0;
1931 			r->ticks = 0;
1932 			tu->qused++;
1933 			tu->qtail++;
1934 		}
1935 	}
1936 	tu->filter = params.filter;
1937 	tu->ticks = params.ticks;
1938 	spin_unlock_irq(&tu->qlock);
1939 	err = 0;
1940  _end:
1941 	if (copy_to_user(_params, &params, sizeof(params)))
1942 		return -EFAULT;
1943 	return err;
1944 }
1945 
snd_timer_user_status32(struct file * file,struct snd_timer_status32 __user * _status)1946 static int snd_timer_user_status32(struct file *file,
1947 				   struct snd_timer_status32 __user *_status)
1948  {
1949 	struct snd_timer_user *tu;
1950 	struct snd_timer_status32 status;
1951 
1952 	tu = file->private_data;
1953 	if (!tu->timeri)
1954 		return -EBADFD;
1955 	memset(&status, 0, sizeof(status));
1956 	status.tstamp_sec = tu->tstamp.tv_sec;
1957 	status.tstamp_nsec = tu->tstamp.tv_nsec;
1958 	status.resolution = snd_timer_resolution(tu->timeri);
1959 	status.lost = tu->timeri->lost;
1960 	status.overrun = tu->overrun;
1961 	spin_lock_irq(&tu->qlock);
1962 	status.queue = tu->qused;
1963 	spin_unlock_irq(&tu->qlock);
1964 	if (copy_to_user(_status, &status, sizeof(status)))
1965 		return -EFAULT;
1966 	return 0;
1967 }
1968 
snd_timer_user_status64(struct file * file,struct snd_timer_status64 __user * _status)1969 static int snd_timer_user_status64(struct file *file,
1970 				   struct snd_timer_status64 __user *_status)
1971 {
1972 	struct snd_timer_user *tu;
1973 	struct snd_timer_status64 status;
1974 
1975 	tu = file->private_data;
1976 	if (!tu->timeri)
1977 		return -EBADFD;
1978 	memset(&status, 0, sizeof(status));
1979 	status.tstamp_sec = tu->tstamp.tv_sec;
1980 	status.tstamp_nsec = tu->tstamp.tv_nsec;
1981 	status.resolution = snd_timer_resolution(tu->timeri);
1982 	status.lost = tu->timeri->lost;
1983 	status.overrun = tu->overrun;
1984 	spin_lock_irq(&tu->qlock);
1985 	status.queue = tu->qused;
1986 	spin_unlock_irq(&tu->qlock);
1987 	if (copy_to_user(_status, &status, sizeof(status)))
1988 		return -EFAULT;
1989 	return 0;
1990 }
1991 
snd_timer_user_start(struct file * file)1992 static int snd_timer_user_start(struct file *file)
1993 {
1994 	int err;
1995 	struct snd_timer_user *tu;
1996 
1997 	tu = file->private_data;
1998 	if (!tu->timeri)
1999 		return -EBADFD;
2000 	snd_timer_stop(tu->timeri);
2001 	tu->timeri->lost = 0;
2002 	tu->last_resolution = 0;
2003 	err = snd_timer_start(tu->timeri, tu->ticks);
2004 	if (err < 0)
2005 		return err;
2006 	return 0;
2007 }
2008 
snd_timer_user_stop(struct file * file)2009 static int snd_timer_user_stop(struct file *file)
2010 {
2011 	int err;
2012 	struct snd_timer_user *tu;
2013 
2014 	tu = file->private_data;
2015 	if (!tu->timeri)
2016 		return -EBADFD;
2017 	err = snd_timer_stop(tu->timeri);
2018 	if (err < 0)
2019 		return err;
2020 	return 0;
2021 }
2022 
snd_timer_user_continue(struct file * file)2023 static int snd_timer_user_continue(struct file *file)
2024 {
2025 	int err;
2026 	struct snd_timer_user *tu;
2027 
2028 	tu = file->private_data;
2029 	if (!tu->timeri)
2030 		return -EBADFD;
2031 	/* start timer instead of continue if it's not used before */
2032 	if (!(tu->timeri->flags & SNDRV_TIMER_IFLG_PAUSED))
2033 		return snd_timer_user_start(file);
2034 	tu->timeri->lost = 0;
2035 	err = snd_timer_continue(tu->timeri);
2036 	if (err < 0)
2037 		return err;
2038 	return 0;
2039 }
2040 
snd_timer_user_pause(struct file * file)2041 static int snd_timer_user_pause(struct file *file)
2042 {
2043 	int err;
2044 	struct snd_timer_user *tu;
2045 
2046 	tu = file->private_data;
2047 	if (!tu->timeri)
2048 		return -EBADFD;
2049 	err = snd_timer_pause(tu->timeri);
2050 	if (err < 0)
2051 		return err;
2052 	return 0;
2053 }
2054 
snd_timer_user_tread(void __user * argp,struct snd_timer_user * tu,unsigned int cmd,bool compat)2055 static int snd_timer_user_tread(void __user *argp, struct snd_timer_user *tu,
2056 				unsigned int cmd, bool compat)
2057 {
2058 	int __user *p = argp;
2059 	int xarg, old_tread;
2060 
2061 	if (tu->timeri)	/* too late */
2062 		return -EBUSY;
2063 	if (get_user(xarg, p))
2064 		return -EFAULT;
2065 
2066 	old_tread = tu->tread;
2067 
2068 	if (!xarg)
2069 		tu->tread = TREAD_FORMAT_NONE;
2070 	else if (cmd == SNDRV_TIMER_IOCTL_TREAD64 ||
2071 		 (IS_ENABLED(CONFIG_64BIT) && !compat))
2072 		tu->tread = TREAD_FORMAT_TIME64;
2073 	else
2074 		tu->tread = TREAD_FORMAT_TIME32;
2075 
2076 	if (tu->tread != old_tread &&
2077 	    realloc_user_queue(tu, tu->queue_size) < 0) {
2078 		tu->tread = old_tread;
2079 		return -ENOMEM;
2080 	}
2081 
2082 	return 0;
2083 }
2084 
2085 enum {
2086 	SNDRV_TIMER_IOCTL_START_OLD = _IO('T', 0x20),
2087 	SNDRV_TIMER_IOCTL_STOP_OLD = _IO('T', 0x21),
2088 	SNDRV_TIMER_IOCTL_CONTINUE_OLD = _IO('T', 0x22),
2089 	SNDRV_TIMER_IOCTL_PAUSE_OLD = _IO('T', 0x23),
2090 };
2091 
__snd_timer_user_ioctl(struct file * file,unsigned int cmd,unsigned long arg,bool compat)2092 static long __snd_timer_user_ioctl(struct file *file, unsigned int cmd,
2093 				 unsigned long arg, bool compat)
2094 {
2095 	struct snd_timer_user *tu;
2096 	void __user *argp = (void __user *)arg;
2097 	int __user *p = argp;
2098 
2099 	tu = file->private_data;
2100 	switch (cmd) {
2101 	case SNDRV_TIMER_IOCTL_PVERSION:
2102 		return put_user(SNDRV_TIMER_VERSION, p) ? -EFAULT : 0;
2103 	case SNDRV_TIMER_IOCTL_NEXT_DEVICE:
2104 		return snd_timer_user_next_device(argp);
2105 	case SNDRV_TIMER_IOCTL_TREAD_OLD:
2106 	case SNDRV_TIMER_IOCTL_TREAD64:
2107 		return snd_timer_user_tread(argp, tu, cmd, compat);
2108 	case SNDRV_TIMER_IOCTL_GINFO:
2109 		return snd_timer_user_ginfo(file, argp);
2110 	case SNDRV_TIMER_IOCTL_GPARAMS:
2111 		return snd_timer_user_gparams(file, argp);
2112 	case SNDRV_TIMER_IOCTL_GSTATUS:
2113 		return snd_timer_user_gstatus(file, argp);
2114 	case SNDRV_TIMER_IOCTL_SELECT:
2115 		return snd_timer_user_tselect(file, argp);
2116 	case SNDRV_TIMER_IOCTL_INFO:
2117 		return snd_timer_user_info(file, argp);
2118 	case SNDRV_TIMER_IOCTL_PARAMS:
2119 		return snd_timer_user_params(file, argp);
2120 	case SNDRV_TIMER_IOCTL_STATUS32:
2121 		return snd_timer_user_status32(file, argp);
2122 	case SNDRV_TIMER_IOCTL_STATUS64:
2123 		return snd_timer_user_status64(file, argp);
2124 	case SNDRV_TIMER_IOCTL_START:
2125 	case SNDRV_TIMER_IOCTL_START_OLD:
2126 		return snd_timer_user_start(file);
2127 	case SNDRV_TIMER_IOCTL_STOP:
2128 	case SNDRV_TIMER_IOCTL_STOP_OLD:
2129 		return snd_timer_user_stop(file);
2130 	case SNDRV_TIMER_IOCTL_CONTINUE:
2131 	case SNDRV_TIMER_IOCTL_CONTINUE_OLD:
2132 		return snd_timer_user_continue(file);
2133 	case SNDRV_TIMER_IOCTL_PAUSE:
2134 	case SNDRV_TIMER_IOCTL_PAUSE_OLD:
2135 		return snd_timer_user_pause(file);
2136 	}
2137 	return -ENOTTY;
2138 }
2139 
snd_timer_user_ioctl(struct file * file,unsigned int cmd,unsigned long arg)2140 static long snd_timer_user_ioctl(struct file *file, unsigned int cmd,
2141 				 unsigned long arg)
2142 {
2143 	struct snd_timer_user *tu = file->private_data;
2144 	long ret;
2145 
2146 	mutex_lock(&tu->ioctl_lock);
2147 	ret = __snd_timer_user_ioctl(file, cmd, arg, false);
2148 	mutex_unlock(&tu->ioctl_lock);
2149 	return ret;
2150 }
2151 
snd_timer_user_fasync(int fd,struct file * file,int on)2152 static int snd_timer_user_fasync(int fd, struct file * file, int on)
2153 {
2154 	struct snd_timer_user *tu;
2155 
2156 	tu = file->private_data;
2157 	return snd_fasync_helper(fd, file, on, &tu->fasync);
2158 }
2159 
snd_timer_user_read(struct file * file,char __user * buffer,size_t count,loff_t * offset)2160 static ssize_t snd_timer_user_read(struct file *file, char __user *buffer,
2161 				   size_t count, loff_t *offset)
2162 {
2163 	struct snd_timer_tread64 *tread;
2164 	struct snd_timer_tread32 tread32;
2165 	struct snd_timer_user *tu;
2166 	long result = 0, unit;
2167 	int qhead;
2168 	int err = 0;
2169 
2170 	tu = file->private_data;
2171 	switch (tu->tread) {
2172 	case TREAD_FORMAT_TIME64:
2173 		unit = sizeof(struct snd_timer_tread64);
2174 		break;
2175 	case TREAD_FORMAT_TIME32:
2176 		unit = sizeof(struct snd_timer_tread32);
2177 		break;
2178 	case TREAD_FORMAT_NONE:
2179 		unit = sizeof(struct snd_timer_read);
2180 		break;
2181 	default:
2182 		WARN_ONCE(1, "Corrupt snd_timer_user\n");
2183 		return -ENOTSUPP;
2184 	}
2185 
2186 	mutex_lock(&tu->ioctl_lock);
2187 	spin_lock_irq(&tu->qlock);
2188 	while ((long)count - result >= unit) {
2189 		while (!tu->qused) {
2190 			wait_queue_entry_t wait;
2191 
2192 			if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
2193 				err = -EAGAIN;
2194 				goto _error;
2195 			}
2196 
2197 			set_current_state(TASK_INTERRUPTIBLE);
2198 			init_waitqueue_entry(&wait, current);
2199 			add_wait_queue(&tu->qchange_sleep, &wait);
2200 
2201 			spin_unlock_irq(&tu->qlock);
2202 			mutex_unlock(&tu->ioctl_lock);
2203 			schedule();
2204 			mutex_lock(&tu->ioctl_lock);
2205 			spin_lock_irq(&tu->qlock);
2206 
2207 			remove_wait_queue(&tu->qchange_sleep, &wait);
2208 
2209 			if (tu->disconnected) {
2210 				err = -ENODEV;
2211 				goto _error;
2212 			}
2213 			if (signal_pending(current)) {
2214 				err = -ERESTARTSYS;
2215 				goto _error;
2216 			}
2217 		}
2218 
2219 		qhead = tu->qhead++;
2220 		tu->qhead %= tu->queue_size;
2221 		tu->qused--;
2222 		spin_unlock_irq(&tu->qlock);
2223 
2224 		tread = &tu->tqueue[qhead];
2225 
2226 		switch (tu->tread) {
2227 		case TREAD_FORMAT_TIME64:
2228 			if (copy_to_user(buffer, tread,
2229 					 sizeof(struct snd_timer_tread64)))
2230 				err = -EFAULT;
2231 			break;
2232 		case TREAD_FORMAT_TIME32:
2233 			memset(&tread32, 0, sizeof(tread32));
2234 			tread32 = (struct snd_timer_tread32) {
2235 				.event = tread->event,
2236 				.tstamp_sec = tread->tstamp_sec,
2237 				.tstamp_nsec = tread->tstamp_nsec,
2238 				.val = tread->val,
2239 			};
2240 
2241 			if (copy_to_user(buffer, &tread32, sizeof(tread32)))
2242 				err = -EFAULT;
2243 			break;
2244 		case TREAD_FORMAT_NONE:
2245 			if (copy_to_user(buffer, &tu->queue[qhead],
2246 					 sizeof(struct snd_timer_read)))
2247 				err = -EFAULT;
2248 			break;
2249 		default:
2250 			err = -ENOTSUPP;
2251 			break;
2252 		}
2253 
2254 		spin_lock_irq(&tu->qlock);
2255 		if (err < 0)
2256 			goto _error;
2257 		result += unit;
2258 		buffer += unit;
2259 	}
2260  _error:
2261 	spin_unlock_irq(&tu->qlock);
2262 	mutex_unlock(&tu->ioctl_lock);
2263 	return result > 0 ? result : err;
2264 }
2265 
snd_timer_user_poll(struct file * file,poll_table * wait)2266 static __poll_t snd_timer_user_poll(struct file *file, poll_table * wait)
2267 {
2268         __poll_t mask;
2269         struct snd_timer_user *tu;
2270 
2271         tu = file->private_data;
2272 
2273         poll_wait(file, &tu->qchange_sleep, wait);
2274 
2275 	mask = 0;
2276 	spin_lock_irq(&tu->qlock);
2277 	if (tu->qused)
2278 		mask |= EPOLLIN | EPOLLRDNORM;
2279 	if (tu->disconnected)
2280 		mask |= EPOLLERR;
2281 	spin_unlock_irq(&tu->qlock);
2282 
2283 	return mask;
2284 }
2285 
2286 #ifdef CONFIG_COMPAT
2287 #include "timer_compat.c"
2288 #else
2289 #define snd_timer_user_ioctl_compat	NULL
2290 #endif
2291 
2292 static const struct file_operations snd_timer_f_ops =
2293 {
2294 	.owner =	THIS_MODULE,
2295 	.read =		snd_timer_user_read,
2296 	.open =		snd_timer_user_open,
2297 	.release =	snd_timer_user_release,
2298 	.llseek =	no_llseek,
2299 	.poll =		snd_timer_user_poll,
2300 	.unlocked_ioctl =	snd_timer_user_ioctl,
2301 	.compat_ioctl =	snd_timer_user_ioctl_compat,
2302 	.fasync = 	snd_timer_user_fasync,
2303 };
2304 
2305 /* unregister the system timer */
snd_timer_free_all(void)2306 static void snd_timer_free_all(void)
2307 {
2308 	struct snd_timer *timer, *n;
2309 
2310 	list_for_each_entry_safe(timer, n, &snd_timer_list, device_list)
2311 		snd_timer_free(timer);
2312 }
2313 
2314 static struct device *timer_dev;
2315 
2316 /*
2317  *  ENTRY functions
2318  */
2319 
alsa_timer_init(void)2320 static int __init alsa_timer_init(void)
2321 {
2322 	int err;
2323 
2324 	err = snd_device_alloc(&timer_dev, NULL);
2325 	if (err < 0)
2326 		return err;
2327 	dev_set_name(timer_dev, "timer");
2328 
2329 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
2330 	snd_oss_info_register(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1,
2331 			      "system timer");
2332 #endif
2333 
2334 	err = snd_timer_register_system();
2335 	if (err < 0) {
2336 		pr_err("ALSA: unable to register system timer (%i)\n", err);
2337 		goto put_timer;
2338 	}
2339 
2340 	err = snd_register_device(SNDRV_DEVICE_TYPE_TIMER, NULL, 0,
2341 				  &snd_timer_f_ops, NULL, timer_dev);
2342 	if (err < 0) {
2343 		pr_err("ALSA: unable to register timer device (%i)\n", err);
2344 		snd_timer_free_all();
2345 		goto put_timer;
2346 	}
2347 
2348 	snd_timer_proc_init();
2349 	return 0;
2350 
2351 put_timer:
2352 	put_device(timer_dev);
2353 	return err;
2354 }
2355 
alsa_timer_exit(void)2356 static void __exit alsa_timer_exit(void)
2357 {
2358 	snd_unregister_device(timer_dev);
2359 	snd_timer_free_all();
2360 	put_device(timer_dev);
2361 	snd_timer_proc_done();
2362 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
2363 	snd_oss_info_unregister(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1);
2364 #endif
2365 }
2366 
2367 module_init(alsa_timer_init)
2368 module_exit(alsa_timer_exit)
2369