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 	if (start)
557 		timeri->ticks = timeri->cticks = ticks;
558 	else if (!timeri->cticks)
559 		timeri->cticks = 1;
560 	timeri->pticks = 0;
561 
562 	list_move_tail(&timeri->active_list, &timer->active_list_head);
563 	if (timer->running) {
564 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
565 			goto __start_now;
566 		timer->flags |= SNDRV_TIMER_FLG_RESCHED;
567 		timeri->flags |= SNDRV_TIMER_IFLG_START;
568 		result = 1; /* delayed start */
569 	} else {
570 		if (start)
571 			timer->sticks = ticks;
572 		timer->hw.start(timer);
573 	      __start_now:
574 		timer->running++;
575 		timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
576 		result = 0;
577 	}
578 	snd_timer_notify1(timeri, start ? SNDRV_TIMER_EVENT_START :
579 			  SNDRV_TIMER_EVENT_CONTINUE);
580  unlock:
581 	spin_unlock_irqrestore(&timer->lock, flags);
582 	return result;
583 }
584 
585 /* start/continue a slave timer */
snd_timer_start_slave(struct snd_timer_instance * timeri,bool start)586 static int snd_timer_start_slave(struct snd_timer_instance *timeri,
587 				 bool start)
588 {
589 	unsigned long flags;
590 	int err;
591 
592 	spin_lock_irqsave(&slave_active_lock, flags);
593 	if (timeri->flags & SNDRV_TIMER_IFLG_DEAD) {
594 		err = -EINVAL;
595 		goto unlock;
596 	}
597 	if (timeri->flags & SNDRV_TIMER_IFLG_RUNNING) {
598 		err = -EBUSY;
599 		goto unlock;
600 	}
601 	timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
602 	if (timeri->master && timeri->timer) {
603 		spin_lock(&timeri->timer->lock);
604 		list_add_tail(&timeri->active_list,
605 			      &timeri->master->slave_active_head);
606 		snd_timer_notify1(timeri, start ? SNDRV_TIMER_EVENT_START :
607 				  SNDRV_TIMER_EVENT_CONTINUE);
608 		spin_unlock(&timeri->timer->lock);
609 	}
610 	err = 1; /* delayed start */
611  unlock:
612 	spin_unlock_irqrestore(&slave_active_lock, flags);
613 	return err;
614 }
615 
616 /* stop/pause a master timer */
snd_timer_stop1(struct snd_timer_instance * timeri,bool stop)617 static int snd_timer_stop1(struct snd_timer_instance *timeri, bool stop)
618 {
619 	struct snd_timer *timer;
620 	int result = 0;
621 	unsigned long flags;
622 
623 	timer = timeri->timer;
624 	if (!timer)
625 		return -EINVAL;
626 	spin_lock_irqsave(&timer->lock, flags);
627 	list_del_init(&timeri->ack_list);
628 	list_del_init(&timeri->active_list);
629 	if (!(timeri->flags & (SNDRV_TIMER_IFLG_RUNNING |
630 			       SNDRV_TIMER_IFLG_START))) {
631 		result = -EBUSY;
632 		goto unlock;
633 	}
634 	if (timer->card && timer->card->shutdown)
635 		goto unlock;
636 	if (stop) {
637 		timeri->cticks = timeri->ticks;
638 		timeri->pticks = 0;
639 	}
640 	if ((timeri->flags & SNDRV_TIMER_IFLG_RUNNING) &&
641 	    !(--timer->running)) {
642 		timer->hw.stop(timer);
643 		if (timer->flags & SNDRV_TIMER_FLG_RESCHED) {
644 			timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
645 			snd_timer_reschedule(timer, 0);
646 			if (timer->flags & SNDRV_TIMER_FLG_CHANGE) {
647 				timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
648 				timer->hw.start(timer);
649 			}
650 		}
651 	}
652 	timeri->flags &= ~(SNDRV_TIMER_IFLG_RUNNING | SNDRV_TIMER_IFLG_START);
653 	if (stop)
654 		timeri->flags &= ~SNDRV_TIMER_IFLG_PAUSED;
655 	else
656 		timeri->flags |= SNDRV_TIMER_IFLG_PAUSED;
657 	snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :
658 			  SNDRV_TIMER_EVENT_PAUSE);
659  unlock:
660 	spin_unlock_irqrestore(&timer->lock, flags);
661 	return result;
662 }
663 
664 /* stop/pause a slave timer */
snd_timer_stop_slave(struct snd_timer_instance * timeri,bool stop)665 static int snd_timer_stop_slave(struct snd_timer_instance *timeri, bool stop)
666 {
667 	unsigned long flags;
668 	bool running;
669 
670 	spin_lock_irqsave(&slave_active_lock, flags);
671 	running = timeri->flags & SNDRV_TIMER_IFLG_RUNNING;
672 	timeri->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
673 	if (timeri->timer) {
674 		spin_lock(&timeri->timer->lock);
675 		list_del_init(&timeri->ack_list);
676 		list_del_init(&timeri->active_list);
677 		if (running)
678 			snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :
679 					  SNDRV_TIMER_EVENT_PAUSE);
680 		spin_unlock(&timeri->timer->lock);
681 	}
682 	spin_unlock_irqrestore(&slave_active_lock, flags);
683 	return running ? 0 : -EBUSY;
684 }
685 
686 /*
687  *  start the timer instance
688  */
snd_timer_start(struct snd_timer_instance * timeri,unsigned int ticks)689 int snd_timer_start(struct snd_timer_instance *timeri, unsigned int ticks)
690 {
691 	if (timeri == NULL || ticks < 1)
692 		return -EINVAL;
693 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
694 		return snd_timer_start_slave(timeri, true);
695 	else
696 		return snd_timer_start1(timeri, true, ticks);
697 }
698 EXPORT_SYMBOL(snd_timer_start);
699 
700 /*
701  * stop the timer instance.
702  *
703  * do not call this from the timer callback!
704  */
snd_timer_stop(struct snd_timer_instance * timeri)705 int snd_timer_stop(struct snd_timer_instance *timeri)
706 {
707 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
708 		return snd_timer_stop_slave(timeri, true);
709 	else
710 		return snd_timer_stop1(timeri, true);
711 }
712 EXPORT_SYMBOL(snd_timer_stop);
713 
714 /*
715  * start again..  the tick is kept.
716  */
snd_timer_continue(struct snd_timer_instance * timeri)717 int snd_timer_continue(struct snd_timer_instance *timeri)
718 {
719 	/* timer can continue only after pause */
720 	if (!(timeri->flags & SNDRV_TIMER_IFLG_PAUSED))
721 		return -EINVAL;
722 
723 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
724 		return snd_timer_start_slave(timeri, false);
725 	else
726 		return snd_timer_start1(timeri, false, 0);
727 }
728 EXPORT_SYMBOL(snd_timer_continue);
729 
730 /*
731  * pause.. remember the ticks left
732  */
snd_timer_pause(struct snd_timer_instance * timeri)733 int snd_timer_pause(struct snd_timer_instance * timeri)
734 {
735 	if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
736 		return snd_timer_stop_slave(timeri, false);
737 	else
738 		return snd_timer_stop1(timeri, false);
739 }
740 EXPORT_SYMBOL(snd_timer_pause);
741 
742 /*
743  * reschedule the timer
744  *
745  * start pending instances and check the scheduling ticks.
746  * when the scheduling ticks is changed set CHANGE flag to reprogram the timer.
747  */
snd_timer_reschedule(struct snd_timer * timer,unsigned long ticks_left)748 static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left)
749 {
750 	struct snd_timer_instance *ti;
751 	unsigned long ticks = ~0UL;
752 
753 	list_for_each_entry(ti, &timer->active_list_head, active_list) {
754 		if (ti->flags & SNDRV_TIMER_IFLG_START) {
755 			ti->flags &= ~SNDRV_TIMER_IFLG_START;
756 			ti->flags |= SNDRV_TIMER_IFLG_RUNNING;
757 			timer->running++;
758 		}
759 		if (ti->flags & SNDRV_TIMER_IFLG_RUNNING) {
760 			if (ticks > ti->cticks)
761 				ticks = ti->cticks;
762 		}
763 	}
764 	if (ticks == ~0UL) {
765 		timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
766 		return;
767 	}
768 	if (ticks > timer->hw.ticks)
769 		ticks = timer->hw.ticks;
770 	if (ticks_left != ticks)
771 		timer->flags |= SNDRV_TIMER_FLG_CHANGE;
772 	timer->sticks = ticks;
773 }
774 
775 /* call callbacks in timer ack list */
snd_timer_process_callbacks(struct snd_timer * timer,struct list_head * head)776 static void snd_timer_process_callbacks(struct snd_timer *timer,
777 					struct list_head *head)
778 {
779 	struct snd_timer_instance *ti;
780 	unsigned long resolution, ticks;
781 
782 	while (!list_empty(head)) {
783 		ti = list_first_entry(head, struct snd_timer_instance,
784 				      ack_list);
785 
786 		/* remove from ack_list and make empty */
787 		list_del_init(&ti->ack_list);
788 
789 		if (!(ti->flags & SNDRV_TIMER_IFLG_DEAD)) {
790 			ticks = ti->pticks;
791 			ti->pticks = 0;
792 			resolution = ti->resolution;
793 			ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
794 			spin_unlock(&timer->lock);
795 			if (ti->callback)
796 				ti->callback(ti, resolution, ticks);
797 			spin_lock(&timer->lock);
798 			ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
799 		}
800 	}
801 }
802 
803 /* clear pending instances from ack list */
snd_timer_clear_callbacks(struct snd_timer * timer,struct list_head * head)804 static void snd_timer_clear_callbacks(struct snd_timer *timer,
805 				      struct list_head *head)
806 {
807 	unsigned long flags;
808 
809 	spin_lock_irqsave(&timer->lock, flags);
810 	while (!list_empty(head))
811 		list_del_init(head->next);
812 	spin_unlock_irqrestore(&timer->lock, flags);
813 }
814 
815 /*
816  * timer work
817  *
818  */
snd_timer_work(struct work_struct * work)819 static void snd_timer_work(struct work_struct *work)
820 {
821 	struct snd_timer *timer = container_of(work, struct snd_timer, task_work);
822 	unsigned long flags;
823 
824 	if (timer->card && timer->card->shutdown) {
825 		snd_timer_clear_callbacks(timer, &timer->sack_list_head);
826 		return;
827 	}
828 
829 	spin_lock_irqsave(&timer->lock, flags);
830 	snd_timer_process_callbacks(timer, &timer->sack_list_head);
831 	spin_unlock_irqrestore(&timer->lock, flags);
832 }
833 
834 /*
835  * timer interrupt
836  *
837  * ticks_left is usually equal to timer->sticks.
838  *
839  */
snd_timer_interrupt(struct snd_timer * timer,unsigned long ticks_left)840 void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
841 {
842 	struct snd_timer_instance *ti, *ts, *tmp;
843 	unsigned long resolution;
844 	struct list_head *ack_list_head;
845 	unsigned long flags;
846 	bool use_work = false;
847 
848 	if (timer == NULL)
849 		return;
850 
851 	if (timer->card && timer->card->shutdown) {
852 		snd_timer_clear_callbacks(timer, &timer->ack_list_head);
853 		return;
854 	}
855 
856 	spin_lock_irqsave(&timer->lock, flags);
857 
858 	/* remember the current resolution */
859 	resolution = snd_timer_hw_resolution(timer);
860 
861 	/* loop for all active instances
862 	 * Here we cannot use list_for_each_entry because the active_list of a
863 	 * processed instance is relinked to done_list_head before the callback
864 	 * is called.
865 	 */
866 	list_for_each_entry_safe(ti, tmp, &timer->active_list_head,
867 				 active_list) {
868 		if (ti->flags & SNDRV_TIMER_IFLG_DEAD)
869 			continue;
870 		if (!(ti->flags & SNDRV_TIMER_IFLG_RUNNING))
871 			continue;
872 		ti->pticks += ticks_left;
873 		ti->resolution = resolution;
874 		if (ti->cticks < ticks_left)
875 			ti->cticks = 0;
876 		else
877 			ti->cticks -= ticks_left;
878 		if (ti->cticks) /* not expired */
879 			continue;
880 		if (ti->flags & SNDRV_TIMER_IFLG_AUTO) {
881 			ti->cticks = ti->ticks;
882 		} else {
883 			ti->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
884 			--timer->running;
885 			list_del_init(&ti->active_list);
886 		}
887 		if ((timer->hw.flags & SNDRV_TIMER_HW_WORK) ||
888 		    (ti->flags & SNDRV_TIMER_IFLG_FAST))
889 			ack_list_head = &timer->ack_list_head;
890 		else
891 			ack_list_head = &timer->sack_list_head;
892 		if (list_empty(&ti->ack_list))
893 			list_add_tail(&ti->ack_list, ack_list_head);
894 		list_for_each_entry(ts, &ti->slave_active_head, active_list) {
895 			ts->pticks = ti->pticks;
896 			ts->resolution = resolution;
897 			if (list_empty(&ts->ack_list))
898 				list_add_tail(&ts->ack_list, ack_list_head);
899 		}
900 	}
901 	if (timer->flags & SNDRV_TIMER_FLG_RESCHED)
902 		snd_timer_reschedule(timer, timer->sticks);
903 	if (timer->running) {
904 		if (timer->hw.flags & SNDRV_TIMER_HW_STOP) {
905 			timer->hw.stop(timer);
906 			timer->flags |= SNDRV_TIMER_FLG_CHANGE;
907 		}
908 		if (!(timer->hw.flags & SNDRV_TIMER_HW_AUTO) ||
909 		    (timer->flags & SNDRV_TIMER_FLG_CHANGE)) {
910 			/* restart timer */
911 			timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
912 			timer->hw.start(timer);
913 		}
914 	} else {
915 		timer->hw.stop(timer);
916 	}
917 
918 	/* now process all fast callbacks */
919 	snd_timer_process_callbacks(timer, &timer->ack_list_head);
920 
921 	/* do we have any slow callbacks? */
922 	use_work = !list_empty(&timer->sack_list_head);
923 	spin_unlock_irqrestore(&timer->lock, flags);
924 
925 	if (use_work)
926 		queue_work(system_highpri_wq, &timer->task_work);
927 }
928 EXPORT_SYMBOL(snd_timer_interrupt);
929 
930 /*
931 
932  */
933 
snd_timer_new(struct snd_card * card,char * id,struct snd_timer_id * tid,struct snd_timer ** rtimer)934 int snd_timer_new(struct snd_card *card, char *id, struct snd_timer_id *tid,
935 		  struct snd_timer **rtimer)
936 {
937 	struct snd_timer *timer;
938 	int err;
939 	static const struct snd_device_ops ops = {
940 		.dev_free = snd_timer_dev_free,
941 		.dev_register = snd_timer_dev_register,
942 		.dev_disconnect = snd_timer_dev_disconnect,
943 	};
944 
945 	if (snd_BUG_ON(!tid))
946 		return -EINVAL;
947 	if (tid->dev_class == SNDRV_TIMER_CLASS_CARD ||
948 	    tid->dev_class == SNDRV_TIMER_CLASS_PCM) {
949 		if (WARN_ON(!card))
950 			return -EINVAL;
951 	}
952 	if (rtimer)
953 		*rtimer = NULL;
954 	timer = kzalloc(sizeof(*timer), GFP_KERNEL);
955 	if (!timer)
956 		return -ENOMEM;
957 	timer->tmr_class = tid->dev_class;
958 	timer->card = card;
959 	timer->tmr_device = tid->device;
960 	timer->tmr_subdevice = tid->subdevice;
961 	if (id)
962 		strscpy(timer->id, id, sizeof(timer->id));
963 	timer->sticks = 1;
964 	INIT_LIST_HEAD(&timer->device_list);
965 	INIT_LIST_HEAD(&timer->open_list_head);
966 	INIT_LIST_HEAD(&timer->active_list_head);
967 	INIT_LIST_HEAD(&timer->ack_list_head);
968 	INIT_LIST_HEAD(&timer->sack_list_head);
969 	spin_lock_init(&timer->lock);
970 	INIT_WORK(&timer->task_work, snd_timer_work);
971 	timer->max_instances = 1000; /* default limit per timer */
972 	if (card != NULL) {
973 		timer->module = card->module;
974 		err = snd_device_new(card, SNDRV_DEV_TIMER, timer, &ops);
975 		if (err < 0) {
976 			snd_timer_free(timer);
977 			return err;
978 		}
979 	}
980 	if (rtimer)
981 		*rtimer = timer;
982 	return 0;
983 }
984 EXPORT_SYMBOL(snd_timer_new);
985 
snd_timer_free(struct snd_timer * timer)986 static int snd_timer_free(struct snd_timer *timer)
987 {
988 	if (!timer)
989 		return 0;
990 
991 	mutex_lock(&register_mutex);
992 	if (! list_empty(&timer->open_list_head)) {
993 		struct list_head *p, *n;
994 		struct snd_timer_instance *ti;
995 		pr_warn("ALSA: timer %p is busy?\n", timer);
996 		list_for_each_safe(p, n, &timer->open_list_head) {
997 			list_del_init(p);
998 			ti = list_entry(p, struct snd_timer_instance, open_list);
999 			ti->timer = NULL;
1000 		}
1001 	}
1002 	list_del(&timer->device_list);
1003 	mutex_unlock(&register_mutex);
1004 
1005 	if (timer->private_free)
1006 		timer->private_free(timer);
1007 	kfree(timer);
1008 	return 0;
1009 }
1010 
snd_timer_dev_free(struct snd_device * device)1011 static int snd_timer_dev_free(struct snd_device *device)
1012 {
1013 	struct snd_timer *timer = device->device_data;
1014 	return snd_timer_free(timer);
1015 }
1016 
snd_timer_dev_register(struct snd_device * dev)1017 static int snd_timer_dev_register(struct snd_device *dev)
1018 {
1019 	struct snd_timer *timer = dev->device_data;
1020 	struct snd_timer *timer1;
1021 
1022 	if (snd_BUG_ON(!timer || !timer->hw.start || !timer->hw.stop))
1023 		return -ENXIO;
1024 	if (!(timer->hw.flags & SNDRV_TIMER_HW_SLAVE) &&
1025 	    !timer->hw.resolution && timer->hw.c_resolution == NULL)
1026 	    	return -EINVAL;
1027 
1028 	mutex_lock(&register_mutex);
1029 	list_for_each_entry(timer1, &snd_timer_list, device_list) {
1030 		if (timer1->tmr_class > timer->tmr_class)
1031 			break;
1032 		if (timer1->tmr_class < timer->tmr_class)
1033 			continue;
1034 		if (timer1->card && timer->card) {
1035 			if (timer1->card->number > timer->card->number)
1036 				break;
1037 			if (timer1->card->number < timer->card->number)
1038 				continue;
1039 		}
1040 		if (timer1->tmr_device > timer->tmr_device)
1041 			break;
1042 		if (timer1->tmr_device < timer->tmr_device)
1043 			continue;
1044 		if (timer1->tmr_subdevice > timer->tmr_subdevice)
1045 			break;
1046 		if (timer1->tmr_subdevice < timer->tmr_subdevice)
1047 			continue;
1048 		/* conflicts.. */
1049 		mutex_unlock(&register_mutex);
1050 		return -EBUSY;
1051 	}
1052 	list_add_tail(&timer->device_list, &timer1->device_list);
1053 	mutex_unlock(&register_mutex);
1054 	return 0;
1055 }
1056 
snd_timer_dev_disconnect(struct snd_device * device)1057 static int snd_timer_dev_disconnect(struct snd_device *device)
1058 {
1059 	struct snd_timer *timer = device->device_data;
1060 	struct snd_timer_instance *ti;
1061 
1062 	mutex_lock(&register_mutex);
1063 	list_del_init(&timer->device_list);
1064 	/* wake up pending sleepers */
1065 	list_for_each_entry(ti, &timer->open_list_head, open_list) {
1066 		if (ti->disconnect)
1067 			ti->disconnect(ti);
1068 	}
1069 	mutex_unlock(&register_mutex);
1070 	return 0;
1071 }
1072 
snd_timer_notify(struct snd_timer * timer,int event,struct timespec64 * tstamp)1073 void snd_timer_notify(struct snd_timer *timer, int event, struct timespec64 *tstamp)
1074 {
1075 	unsigned long flags;
1076 	unsigned long resolution = 0;
1077 	struct snd_timer_instance *ti, *ts;
1078 
1079 	if (timer->card && timer->card->shutdown)
1080 		return;
1081 	if (! (timer->hw.flags & SNDRV_TIMER_HW_SLAVE))
1082 		return;
1083 	if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_MSTART ||
1084 		       event > SNDRV_TIMER_EVENT_MRESUME))
1085 		return;
1086 	spin_lock_irqsave(&timer->lock, flags);
1087 	if (event == SNDRV_TIMER_EVENT_MSTART ||
1088 	    event == SNDRV_TIMER_EVENT_MCONTINUE ||
1089 	    event == SNDRV_TIMER_EVENT_MRESUME)
1090 		resolution = snd_timer_hw_resolution(timer);
1091 	list_for_each_entry(ti, &timer->active_list_head, active_list) {
1092 		if (ti->ccallback)
1093 			ti->ccallback(ti, event, tstamp, resolution);
1094 		list_for_each_entry(ts, &ti->slave_active_head, active_list)
1095 			if (ts->ccallback)
1096 				ts->ccallback(ts, event, tstamp, resolution);
1097 	}
1098 	spin_unlock_irqrestore(&timer->lock, flags);
1099 }
1100 EXPORT_SYMBOL(snd_timer_notify);
1101 
1102 /*
1103  * exported functions for global timers
1104  */
snd_timer_global_new(char * id,int device,struct snd_timer ** rtimer)1105 int snd_timer_global_new(char *id, int device, struct snd_timer **rtimer)
1106 {
1107 	struct snd_timer_id tid;
1108 
1109 	tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL;
1110 	tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1111 	tid.card = -1;
1112 	tid.device = device;
1113 	tid.subdevice = 0;
1114 	return snd_timer_new(NULL, id, &tid, rtimer);
1115 }
1116 EXPORT_SYMBOL(snd_timer_global_new);
1117 
snd_timer_global_free(struct snd_timer * timer)1118 int snd_timer_global_free(struct snd_timer *timer)
1119 {
1120 	return snd_timer_free(timer);
1121 }
1122 EXPORT_SYMBOL(snd_timer_global_free);
1123 
snd_timer_global_register(struct snd_timer * timer)1124 int snd_timer_global_register(struct snd_timer *timer)
1125 {
1126 	struct snd_device dev;
1127 
1128 	memset(&dev, 0, sizeof(dev));
1129 	dev.device_data = timer;
1130 	return snd_timer_dev_register(&dev);
1131 }
1132 EXPORT_SYMBOL(snd_timer_global_register);
1133 
1134 /*
1135  *  System timer
1136  */
1137 
1138 struct snd_timer_system_private {
1139 	struct timer_list tlist;
1140 	struct snd_timer *snd_timer;
1141 	unsigned long last_expires;
1142 	unsigned long last_jiffies;
1143 	unsigned long correction;
1144 };
1145 
snd_timer_s_function(struct timer_list * t)1146 static void snd_timer_s_function(struct timer_list *t)
1147 {
1148 	struct snd_timer_system_private *priv = from_timer(priv, t,
1149 								tlist);
1150 	struct snd_timer *timer = priv->snd_timer;
1151 	unsigned long jiff = jiffies;
1152 	if (time_after(jiff, priv->last_expires))
1153 		priv->correction += (long)jiff - (long)priv->last_expires;
1154 	snd_timer_interrupt(timer, (long)jiff - (long)priv->last_jiffies);
1155 }
1156 
snd_timer_s_start(struct snd_timer * timer)1157 static int snd_timer_s_start(struct snd_timer * timer)
1158 {
1159 	struct snd_timer_system_private *priv;
1160 	unsigned long njiff;
1161 
1162 	priv = (struct snd_timer_system_private *) timer->private_data;
1163 	njiff = (priv->last_jiffies = jiffies);
1164 	if (priv->correction > timer->sticks - 1) {
1165 		priv->correction -= timer->sticks - 1;
1166 		njiff++;
1167 	} else {
1168 		njiff += timer->sticks - priv->correction;
1169 		priv->correction = 0;
1170 	}
1171 	priv->last_expires = njiff;
1172 	mod_timer(&priv->tlist, njiff);
1173 	return 0;
1174 }
1175 
snd_timer_s_stop(struct snd_timer * timer)1176 static int snd_timer_s_stop(struct snd_timer * timer)
1177 {
1178 	struct snd_timer_system_private *priv;
1179 	unsigned long jiff;
1180 
1181 	priv = (struct snd_timer_system_private *) timer->private_data;
1182 	del_timer(&priv->tlist);
1183 	jiff = jiffies;
1184 	if (time_before(jiff, priv->last_expires))
1185 		timer->sticks = priv->last_expires - jiff;
1186 	else
1187 		timer->sticks = 1;
1188 	priv->correction = 0;
1189 	return 0;
1190 }
1191 
snd_timer_s_close(struct snd_timer * timer)1192 static int snd_timer_s_close(struct snd_timer *timer)
1193 {
1194 	struct snd_timer_system_private *priv;
1195 
1196 	priv = (struct snd_timer_system_private *)timer->private_data;
1197 	del_timer_sync(&priv->tlist);
1198 	return 0;
1199 }
1200 
1201 static const struct snd_timer_hardware snd_timer_system =
1202 {
1203 	.flags =	SNDRV_TIMER_HW_FIRST | SNDRV_TIMER_HW_WORK,
1204 	.resolution =	1000000000L / HZ,
1205 	.ticks =	10000000L,
1206 	.close =	snd_timer_s_close,
1207 	.start =	snd_timer_s_start,
1208 	.stop =		snd_timer_s_stop
1209 };
1210 
snd_timer_free_system(struct snd_timer * timer)1211 static void snd_timer_free_system(struct snd_timer *timer)
1212 {
1213 	kfree(timer->private_data);
1214 }
1215 
snd_timer_register_system(void)1216 static int snd_timer_register_system(void)
1217 {
1218 	struct snd_timer *timer;
1219 	struct snd_timer_system_private *priv;
1220 	int err;
1221 
1222 	err = snd_timer_global_new("system", SNDRV_TIMER_GLOBAL_SYSTEM, &timer);
1223 	if (err < 0)
1224 		return err;
1225 	strcpy(timer->name, "system timer");
1226 	timer->hw = snd_timer_system;
1227 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
1228 	if (priv == NULL) {
1229 		snd_timer_free(timer);
1230 		return -ENOMEM;
1231 	}
1232 	priv->snd_timer = timer;
1233 	timer_setup(&priv->tlist, snd_timer_s_function, 0);
1234 	timer->private_data = priv;
1235 	timer->private_free = snd_timer_free_system;
1236 	return snd_timer_global_register(timer);
1237 }
1238 
1239 #ifdef CONFIG_SND_PROC_FS
1240 /*
1241  *  Info interface
1242  */
1243 
snd_timer_proc_read(struct snd_info_entry * entry,struct snd_info_buffer * buffer)1244 static void snd_timer_proc_read(struct snd_info_entry *entry,
1245 				struct snd_info_buffer *buffer)
1246 {
1247 	struct snd_timer *timer;
1248 	struct snd_timer_instance *ti;
1249 
1250 	mutex_lock(&register_mutex);
1251 	list_for_each_entry(timer, &snd_timer_list, device_list) {
1252 		if (timer->card && timer->card->shutdown)
1253 			continue;
1254 		switch (timer->tmr_class) {
1255 		case SNDRV_TIMER_CLASS_GLOBAL:
1256 			snd_iprintf(buffer, "G%i: ", timer->tmr_device);
1257 			break;
1258 		case SNDRV_TIMER_CLASS_CARD:
1259 			snd_iprintf(buffer, "C%i-%i: ",
1260 				    timer->card->number, timer->tmr_device);
1261 			break;
1262 		case SNDRV_TIMER_CLASS_PCM:
1263 			snd_iprintf(buffer, "P%i-%i-%i: ", timer->card->number,
1264 				    timer->tmr_device, timer->tmr_subdevice);
1265 			break;
1266 		default:
1267 			snd_iprintf(buffer, "?%i-%i-%i-%i: ", timer->tmr_class,
1268 				    timer->card ? timer->card->number : -1,
1269 				    timer->tmr_device, timer->tmr_subdevice);
1270 		}
1271 		snd_iprintf(buffer, "%s :", timer->name);
1272 		if (timer->hw.resolution)
1273 			snd_iprintf(buffer, " %lu.%03luus (%lu ticks)",
1274 				    timer->hw.resolution / 1000,
1275 				    timer->hw.resolution % 1000,
1276 				    timer->hw.ticks);
1277 		if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
1278 			snd_iprintf(buffer, " SLAVE");
1279 		snd_iprintf(buffer, "\n");
1280 		list_for_each_entry(ti, &timer->open_list_head, open_list)
1281 			snd_iprintf(buffer, "  Client %s : %s\n",
1282 				    ti->owner ? ti->owner : "unknown",
1283 				    (ti->flags & (SNDRV_TIMER_IFLG_START |
1284 						  SNDRV_TIMER_IFLG_RUNNING))
1285 				    ? "running" : "stopped");
1286 	}
1287 	mutex_unlock(&register_mutex);
1288 }
1289 
1290 static struct snd_info_entry *snd_timer_proc_entry;
1291 
snd_timer_proc_init(void)1292 static void __init snd_timer_proc_init(void)
1293 {
1294 	struct snd_info_entry *entry;
1295 
1296 	entry = snd_info_create_module_entry(THIS_MODULE, "timers", NULL);
1297 	if (entry != NULL) {
1298 		entry->c.text.read = snd_timer_proc_read;
1299 		if (snd_info_register(entry) < 0) {
1300 			snd_info_free_entry(entry);
1301 			entry = NULL;
1302 		}
1303 	}
1304 	snd_timer_proc_entry = entry;
1305 }
1306 
snd_timer_proc_done(void)1307 static void __exit snd_timer_proc_done(void)
1308 {
1309 	snd_info_free_entry(snd_timer_proc_entry);
1310 }
1311 #else /* !CONFIG_SND_PROC_FS */
1312 #define snd_timer_proc_init()
1313 #define snd_timer_proc_done()
1314 #endif
1315 
1316 /*
1317  *  USER SPACE interface
1318  */
1319 
snd_timer_user_interrupt(struct snd_timer_instance * timeri,unsigned long resolution,unsigned long ticks)1320 static void snd_timer_user_interrupt(struct snd_timer_instance *timeri,
1321 				     unsigned long resolution,
1322 				     unsigned long ticks)
1323 {
1324 	struct snd_timer_user *tu = timeri->callback_data;
1325 	struct snd_timer_read *r;
1326 	int prev;
1327 
1328 	spin_lock(&tu->qlock);
1329 	if (tu->qused > 0) {
1330 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1331 		r = &tu->queue[prev];
1332 		if (r->resolution == resolution) {
1333 			r->ticks += ticks;
1334 			goto __wake;
1335 		}
1336 	}
1337 	if (tu->qused >= tu->queue_size) {
1338 		tu->overrun++;
1339 	} else {
1340 		r = &tu->queue[tu->qtail++];
1341 		tu->qtail %= tu->queue_size;
1342 		r->resolution = resolution;
1343 		r->ticks = ticks;
1344 		tu->qused++;
1345 	}
1346       __wake:
1347 	spin_unlock(&tu->qlock);
1348 	snd_kill_fasync(tu->fasync, SIGIO, POLL_IN);
1349 	wake_up(&tu->qchange_sleep);
1350 }
1351 
snd_timer_user_append_to_tqueue(struct snd_timer_user * tu,struct snd_timer_tread64 * tread)1352 static void snd_timer_user_append_to_tqueue(struct snd_timer_user *tu,
1353 					    struct snd_timer_tread64 *tread)
1354 {
1355 	if (tu->qused >= tu->queue_size) {
1356 		tu->overrun++;
1357 	} else {
1358 		memcpy(&tu->tqueue[tu->qtail++], tread, sizeof(*tread));
1359 		tu->qtail %= tu->queue_size;
1360 		tu->qused++;
1361 	}
1362 }
1363 
snd_timer_user_ccallback(struct snd_timer_instance * timeri,int event,struct timespec64 * tstamp,unsigned long resolution)1364 static void snd_timer_user_ccallback(struct snd_timer_instance *timeri,
1365 				     int event,
1366 				     struct timespec64 *tstamp,
1367 				     unsigned long resolution)
1368 {
1369 	struct snd_timer_user *tu = timeri->callback_data;
1370 	struct snd_timer_tread64 r1;
1371 	unsigned long flags;
1372 
1373 	if (event >= SNDRV_TIMER_EVENT_START &&
1374 	    event <= SNDRV_TIMER_EVENT_PAUSE)
1375 		tu->tstamp = *tstamp;
1376 	if ((tu->filter & (1 << event)) == 0 || !tu->tread)
1377 		return;
1378 	memset(&r1, 0, sizeof(r1));
1379 	r1.event = event;
1380 	r1.tstamp_sec = tstamp->tv_sec;
1381 	r1.tstamp_nsec = tstamp->tv_nsec;
1382 	r1.val = resolution;
1383 	spin_lock_irqsave(&tu->qlock, flags);
1384 	snd_timer_user_append_to_tqueue(tu, &r1);
1385 	spin_unlock_irqrestore(&tu->qlock, flags);
1386 	snd_kill_fasync(tu->fasync, SIGIO, POLL_IN);
1387 	wake_up(&tu->qchange_sleep);
1388 }
1389 
snd_timer_user_disconnect(struct snd_timer_instance * timeri)1390 static void snd_timer_user_disconnect(struct snd_timer_instance *timeri)
1391 {
1392 	struct snd_timer_user *tu = timeri->callback_data;
1393 
1394 	tu->disconnected = true;
1395 	wake_up(&tu->qchange_sleep);
1396 }
1397 
snd_timer_user_tinterrupt(struct snd_timer_instance * timeri,unsigned long resolution,unsigned long ticks)1398 static void snd_timer_user_tinterrupt(struct snd_timer_instance *timeri,
1399 				      unsigned long resolution,
1400 				      unsigned long ticks)
1401 {
1402 	struct snd_timer_user *tu = timeri->callback_data;
1403 	struct snd_timer_tread64 *r, r1;
1404 	struct timespec64 tstamp;
1405 	int prev, append = 0;
1406 
1407 	memset(&r1, 0, sizeof(r1));
1408 	memset(&tstamp, 0, sizeof(tstamp));
1409 	spin_lock(&tu->qlock);
1410 	if ((tu->filter & ((1 << SNDRV_TIMER_EVENT_RESOLUTION) |
1411 			   (1 << SNDRV_TIMER_EVENT_TICK))) == 0) {
1412 		spin_unlock(&tu->qlock);
1413 		return;
1414 	}
1415 	if (tu->last_resolution != resolution || ticks > 0) {
1416 		if (timer_tstamp_monotonic)
1417 			ktime_get_ts64(&tstamp);
1418 		else
1419 			ktime_get_real_ts64(&tstamp);
1420 	}
1421 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_RESOLUTION)) &&
1422 	    tu->last_resolution != resolution) {
1423 		r1.event = SNDRV_TIMER_EVENT_RESOLUTION;
1424 		r1.tstamp_sec = tstamp.tv_sec;
1425 		r1.tstamp_nsec = tstamp.tv_nsec;
1426 		r1.val = resolution;
1427 		snd_timer_user_append_to_tqueue(tu, &r1);
1428 		tu->last_resolution = resolution;
1429 		append++;
1430 	}
1431 	if ((tu->filter & (1 << SNDRV_TIMER_EVENT_TICK)) == 0)
1432 		goto __wake;
1433 	if (ticks == 0)
1434 		goto __wake;
1435 	if (tu->qused > 0) {
1436 		prev = tu->qtail == 0 ? tu->queue_size - 1 : tu->qtail - 1;
1437 		r = &tu->tqueue[prev];
1438 		if (r->event == SNDRV_TIMER_EVENT_TICK) {
1439 			r->tstamp_sec = tstamp.tv_sec;
1440 			r->tstamp_nsec = tstamp.tv_nsec;
1441 			r->val += ticks;
1442 			append++;
1443 			goto __wake;
1444 		}
1445 	}
1446 	r1.event = SNDRV_TIMER_EVENT_TICK;
1447 	r1.tstamp_sec = tstamp.tv_sec;
1448 	r1.tstamp_nsec = tstamp.tv_nsec;
1449 	r1.val = ticks;
1450 	snd_timer_user_append_to_tqueue(tu, &r1);
1451 	append++;
1452       __wake:
1453 	spin_unlock(&tu->qlock);
1454 	if (append == 0)
1455 		return;
1456 	snd_kill_fasync(tu->fasync, SIGIO, POLL_IN);
1457 	wake_up(&tu->qchange_sleep);
1458 }
1459 
realloc_user_queue(struct snd_timer_user * tu,int size)1460 static int realloc_user_queue(struct snd_timer_user *tu, int size)
1461 {
1462 	struct snd_timer_read *queue = NULL;
1463 	struct snd_timer_tread64 *tqueue = NULL;
1464 
1465 	if (tu->tread) {
1466 		tqueue = kcalloc(size, sizeof(*tqueue), GFP_KERNEL);
1467 		if (!tqueue)
1468 			return -ENOMEM;
1469 	} else {
1470 		queue = kcalloc(size, sizeof(*queue), GFP_KERNEL);
1471 		if (!queue)
1472 			return -ENOMEM;
1473 	}
1474 
1475 	spin_lock_irq(&tu->qlock);
1476 	kfree(tu->queue);
1477 	kfree(tu->tqueue);
1478 	tu->queue_size = size;
1479 	tu->queue = queue;
1480 	tu->tqueue = tqueue;
1481 	tu->qhead = tu->qtail = tu->qused = 0;
1482 	spin_unlock_irq(&tu->qlock);
1483 
1484 	return 0;
1485 }
1486 
snd_timer_user_open(struct inode * inode,struct file * file)1487 static int snd_timer_user_open(struct inode *inode, struct file *file)
1488 {
1489 	struct snd_timer_user *tu;
1490 	int err;
1491 
1492 	err = stream_open(inode, file);
1493 	if (err < 0)
1494 		return err;
1495 
1496 	tu = kzalloc(sizeof(*tu), GFP_KERNEL);
1497 	if (tu == NULL)
1498 		return -ENOMEM;
1499 	spin_lock_init(&tu->qlock);
1500 	init_waitqueue_head(&tu->qchange_sleep);
1501 	mutex_init(&tu->ioctl_lock);
1502 	tu->ticks = 1;
1503 	if (realloc_user_queue(tu, 128) < 0) {
1504 		kfree(tu);
1505 		return -ENOMEM;
1506 	}
1507 	file->private_data = tu;
1508 	return 0;
1509 }
1510 
snd_timer_user_release(struct inode * inode,struct file * file)1511 static int snd_timer_user_release(struct inode *inode, struct file *file)
1512 {
1513 	struct snd_timer_user *tu;
1514 
1515 	if (file->private_data) {
1516 		tu = file->private_data;
1517 		file->private_data = NULL;
1518 		mutex_lock(&tu->ioctl_lock);
1519 		if (tu->timeri) {
1520 			snd_timer_close(tu->timeri);
1521 			snd_timer_instance_free(tu->timeri);
1522 		}
1523 		mutex_unlock(&tu->ioctl_lock);
1524 		snd_fasync_free(tu->fasync);
1525 		kfree(tu->queue);
1526 		kfree(tu->tqueue);
1527 		kfree(tu);
1528 	}
1529 	return 0;
1530 }
1531 
snd_timer_user_zero_id(struct snd_timer_id * id)1532 static void snd_timer_user_zero_id(struct snd_timer_id *id)
1533 {
1534 	id->dev_class = SNDRV_TIMER_CLASS_NONE;
1535 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1536 	id->card = -1;
1537 	id->device = -1;
1538 	id->subdevice = -1;
1539 }
1540 
snd_timer_user_copy_id(struct snd_timer_id * id,struct snd_timer * timer)1541 static void snd_timer_user_copy_id(struct snd_timer_id *id, struct snd_timer *timer)
1542 {
1543 	id->dev_class = timer->tmr_class;
1544 	id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1545 	id->card = timer->card ? timer->card->number : -1;
1546 	id->device = timer->tmr_device;
1547 	id->subdevice = timer->tmr_subdevice;
1548 }
1549 
snd_timer_user_next_device(struct snd_timer_id __user * _tid)1550 static int snd_timer_user_next_device(struct snd_timer_id __user *_tid)
1551 {
1552 	struct snd_timer_id id;
1553 	struct snd_timer *timer;
1554 	struct list_head *p;
1555 
1556 	if (copy_from_user(&id, _tid, sizeof(id)))
1557 		return -EFAULT;
1558 	mutex_lock(&register_mutex);
1559 	if (id.dev_class < 0) {		/* first item */
1560 		if (list_empty(&snd_timer_list))
1561 			snd_timer_user_zero_id(&id);
1562 		else {
1563 			timer = list_entry(snd_timer_list.next,
1564 					   struct snd_timer, device_list);
1565 			snd_timer_user_copy_id(&id, timer);
1566 		}
1567 	} else {
1568 		switch (id.dev_class) {
1569 		case SNDRV_TIMER_CLASS_GLOBAL:
1570 			id.device = id.device < 0 ? 0 : id.device + 1;
1571 			list_for_each(p, &snd_timer_list) {
1572 				timer = list_entry(p, struct snd_timer, device_list);
1573 				if (timer->tmr_class > SNDRV_TIMER_CLASS_GLOBAL) {
1574 					snd_timer_user_copy_id(&id, timer);
1575 					break;
1576 				}
1577 				if (timer->tmr_device >= id.device) {
1578 					snd_timer_user_copy_id(&id, timer);
1579 					break;
1580 				}
1581 			}
1582 			if (p == &snd_timer_list)
1583 				snd_timer_user_zero_id(&id);
1584 			break;
1585 		case SNDRV_TIMER_CLASS_CARD:
1586 		case SNDRV_TIMER_CLASS_PCM:
1587 			if (id.card < 0) {
1588 				id.card = 0;
1589 			} else {
1590 				if (id.device < 0) {
1591 					id.device = 0;
1592 				} else {
1593 					if (id.subdevice < 0)
1594 						id.subdevice = 0;
1595 					else if (id.subdevice < INT_MAX)
1596 						id.subdevice++;
1597 				}
1598 			}
1599 			list_for_each(p, &snd_timer_list) {
1600 				timer = list_entry(p, struct snd_timer, device_list);
1601 				if (timer->tmr_class > id.dev_class) {
1602 					snd_timer_user_copy_id(&id, timer);
1603 					break;
1604 				}
1605 				if (timer->tmr_class < id.dev_class)
1606 					continue;
1607 				if (timer->card->number > id.card) {
1608 					snd_timer_user_copy_id(&id, timer);
1609 					break;
1610 				}
1611 				if (timer->card->number < id.card)
1612 					continue;
1613 				if (timer->tmr_device > id.device) {
1614 					snd_timer_user_copy_id(&id, timer);
1615 					break;
1616 				}
1617 				if (timer->tmr_device < id.device)
1618 					continue;
1619 				if (timer->tmr_subdevice > id.subdevice) {
1620 					snd_timer_user_copy_id(&id, timer);
1621 					break;
1622 				}
1623 				if (timer->tmr_subdevice < id.subdevice)
1624 					continue;
1625 				snd_timer_user_copy_id(&id, timer);
1626 				break;
1627 			}
1628 			if (p == &snd_timer_list)
1629 				snd_timer_user_zero_id(&id);
1630 			break;
1631 		default:
1632 			snd_timer_user_zero_id(&id);
1633 		}
1634 	}
1635 	mutex_unlock(&register_mutex);
1636 	if (copy_to_user(_tid, &id, sizeof(*_tid)))
1637 		return -EFAULT;
1638 	return 0;
1639 }
1640 
snd_timer_user_ginfo(struct file * file,struct snd_timer_ginfo __user * _ginfo)1641 static int snd_timer_user_ginfo(struct file *file,
1642 				struct snd_timer_ginfo __user *_ginfo)
1643 {
1644 	struct snd_timer_ginfo *ginfo;
1645 	struct snd_timer_id tid;
1646 	struct snd_timer *t;
1647 	struct list_head *p;
1648 	int err = 0;
1649 
1650 	ginfo = memdup_user(_ginfo, sizeof(*ginfo));
1651 	if (IS_ERR(ginfo))
1652 		return PTR_ERR(ginfo);
1653 
1654 	tid = ginfo->tid;
1655 	memset(ginfo, 0, sizeof(*ginfo));
1656 	ginfo->tid = tid;
1657 	mutex_lock(&register_mutex);
1658 	t = snd_timer_find(&tid);
1659 	if (t != NULL) {
1660 		ginfo->card = t->card ? t->card->number : -1;
1661 		if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1662 			ginfo->flags |= SNDRV_TIMER_FLG_SLAVE;
1663 		strscpy(ginfo->id, t->id, sizeof(ginfo->id));
1664 		strscpy(ginfo->name, t->name, sizeof(ginfo->name));
1665 		ginfo->resolution = t->hw.resolution;
1666 		if (t->hw.resolution_min > 0) {
1667 			ginfo->resolution_min = t->hw.resolution_min;
1668 			ginfo->resolution_max = t->hw.resolution_max;
1669 		}
1670 		list_for_each(p, &t->open_list_head) {
1671 			ginfo->clients++;
1672 		}
1673 	} else {
1674 		err = -ENODEV;
1675 	}
1676 	mutex_unlock(&register_mutex);
1677 	if (err >= 0 && copy_to_user(_ginfo, ginfo, sizeof(*ginfo)))
1678 		err = -EFAULT;
1679 	kfree(ginfo);
1680 	return err;
1681 }
1682 
timer_set_gparams(struct snd_timer_gparams * gparams)1683 static int timer_set_gparams(struct snd_timer_gparams *gparams)
1684 {
1685 	struct snd_timer *t;
1686 	int err;
1687 
1688 	mutex_lock(&register_mutex);
1689 	t = snd_timer_find(&gparams->tid);
1690 	if (!t) {
1691 		err = -ENODEV;
1692 		goto _error;
1693 	}
1694 	if (!list_empty(&t->open_list_head)) {
1695 		err = -EBUSY;
1696 		goto _error;
1697 	}
1698 	if (!t->hw.set_period) {
1699 		err = -ENOSYS;
1700 		goto _error;
1701 	}
1702 	err = t->hw.set_period(t, gparams->period_num, gparams->period_den);
1703 _error:
1704 	mutex_unlock(&register_mutex);
1705 	return err;
1706 }
1707 
snd_timer_user_gparams(struct file * file,struct snd_timer_gparams __user * _gparams)1708 static int snd_timer_user_gparams(struct file *file,
1709 				  struct snd_timer_gparams __user *_gparams)
1710 {
1711 	struct snd_timer_gparams gparams;
1712 
1713 	if (copy_from_user(&gparams, _gparams, sizeof(gparams)))
1714 		return -EFAULT;
1715 	return timer_set_gparams(&gparams);
1716 }
1717 
snd_timer_user_gstatus(struct file * file,struct snd_timer_gstatus __user * _gstatus)1718 static int snd_timer_user_gstatus(struct file *file,
1719 				  struct snd_timer_gstatus __user *_gstatus)
1720 {
1721 	struct snd_timer_gstatus gstatus;
1722 	struct snd_timer_id tid;
1723 	struct snd_timer *t;
1724 	int err = 0;
1725 
1726 	if (copy_from_user(&gstatus, _gstatus, sizeof(gstatus)))
1727 		return -EFAULT;
1728 	tid = gstatus.tid;
1729 	memset(&gstatus, 0, sizeof(gstatus));
1730 	gstatus.tid = tid;
1731 	mutex_lock(&register_mutex);
1732 	t = snd_timer_find(&tid);
1733 	if (t != NULL) {
1734 		spin_lock_irq(&t->lock);
1735 		gstatus.resolution = snd_timer_hw_resolution(t);
1736 		if (t->hw.precise_resolution) {
1737 			t->hw.precise_resolution(t, &gstatus.resolution_num,
1738 						 &gstatus.resolution_den);
1739 		} else {
1740 			gstatus.resolution_num = gstatus.resolution;
1741 			gstatus.resolution_den = 1000000000uL;
1742 		}
1743 		spin_unlock_irq(&t->lock);
1744 	} else {
1745 		err = -ENODEV;
1746 	}
1747 	mutex_unlock(&register_mutex);
1748 	if (err >= 0 && copy_to_user(_gstatus, &gstatus, sizeof(gstatus)))
1749 		err = -EFAULT;
1750 	return err;
1751 }
1752 
snd_timer_user_tselect(struct file * file,struct snd_timer_select __user * _tselect)1753 static int snd_timer_user_tselect(struct file *file,
1754 				  struct snd_timer_select __user *_tselect)
1755 {
1756 	struct snd_timer_user *tu;
1757 	struct snd_timer_select tselect;
1758 	char str[32];
1759 	int err = 0;
1760 
1761 	tu = file->private_data;
1762 	if (tu->timeri) {
1763 		snd_timer_close(tu->timeri);
1764 		snd_timer_instance_free(tu->timeri);
1765 		tu->timeri = NULL;
1766 	}
1767 	if (copy_from_user(&tselect, _tselect, sizeof(tselect))) {
1768 		err = -EFAULT;
1769 		goto __err;
1770 	}
1771 	sprintf(str, "application %i", current->pid);
1772 	if (tselect.id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
1773 		tselect.id.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION;
1774 	tu->timeri = snd_timer_instance_new(str);
1775 	if (!tu->timeri) {
1776 		err = -ENOMEM;
1777 		goto __err;
1778 	}
1779 
1780 	tu->timeri->flags |= SNDRV_TIMER_IFLG_FAST;
1781 	tu->timeri->callback = tu->tread
1782 			? snd_timer_user_tinterrupt : snd_timer_user_interrupt;
1783 	tu->timeri->ccallback = snd_timer_user_ccallback;
1784 	tu->timeri->callback_data = (void *)tu;
1785 	tu->timeri->disconnect = snd_timer_user_disconnect;
1786 
1787 	err = snd_timer_open(tu->timeri, &tselect.id, current->pid);
1788 	if (err < 0) {
1789 		snd_timer_instance_free(tu->timeri);
1790 		tu->timeri = NULL;
1791 	}
1792 
1793       __err:
1794 	return err;
1795 }
1796 
snd_timer_user_info(struct file * file,struct snd_timer_info __user * _info)1797 static int snd_timer_user_info(struct file *file,
1798 			       struct snd_timer_info __user *_info)
1799 {
1800 	struct snd_timer_user *tu;
1801 	struct snd_timer_info *info;
1802 	struct snd_timer *t;
1803 	int err = 0;
1804 
1805 	tu = file->private_data;
1806 	if (!tu->timeri)
1807 		return -EBADFD;
1808 	t = tu->timeri->timer;
1809 	if (!t)
1810 		return -EBADFD;
1811 
1812 	info = kzalloc(sizeof(*info), GFP_KERNEL);
1813 	if (! info)
1814 		return -ENOMEM;
1815 	info->card = t->card ? t->card->number : -1;
1816 	if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1817 		info->flags |= SNDRV_TIMER_FLG_SLAVE;
1818 	strscpy(info->id, t->id, sizeof(info->id));
1819 	strscpy(info->name, t->name, sizeof(info->name));
1820 	info->resolution = t->hw.resolution;
1821 	if (copy_to_user(_info, info, sizeof(*_info)))
1822 		err = -EFAULT;
1823 	kfree(info);
1824 	return err;
1825 }
1826 
snd_timer_user_params(struct file * file,struct snd_timer_params __user * _params)1827 static int snd_timer_user_params(struct file *file,
1828 				 struct snd_timer_params __user *_params)
1829 {
1830 	struct snd_timer_user *tu;
1831 	struct snd_timer_params params;
1832 	struct snd_timer *t;
1833 	int err;
1834 
1835 	tu = file->private_data;
1836 	if (!tu->timeri)
1837 		return -EBADFD;
1838 	t = tu->timeri->timer;
1839 	if (!t)
1840 		return -EBADFD;
1841 	if (copy_from_user(&params, _params, sizeof(params)))
1842 		return -EFAULT;
1843 	if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE)) {
1844 		u64 resolution;
1845 
1846 		if (params.ticks < 1) {
1847 			err = -EINVAL;
1848 			goto _end;
1849 		}
1850 
1851 		/* Don't allow resolution less than 1ms */
1852 		resolution = snd_timer_resolution(tu->timeri);
1853 		resolution *= params.ticks;
1854 		if (resolution < 1000000) {
1855 			err = -EINVAL;
1856 			goto _end;
1857 		}
1858 	}
1859 	if (params.queue_size > 0 &&
1860 	    (params.queue_size < 32 || params.queue_size > 1024)) {
1861 		err = -EINVAL;
1862 		goto _end;
1863 	}
1864 	if (params.filter & ~((1<<SNDRV_TIMER_EVENT_RESOLUTION)|
1865 			      (1<<SNDRV_TIMER_EVENT_TICK)|
1866 			      (1<<SNDRV_TIMER_EVENT_START)|
1867 			      (1<<SNDRV_TIMER_EVENT_STOP)|
1868 			      (1<<SNDRV_TIMER_EVENT_CONTINUE)|
1869 			      (1<<SNDRV_TIMER_EVENT_PAUSE)|
1870 			      (1<<SNDRV_TIMER_EVENT_SUSPEND)|
1871 			      (1<<SNDRV_TIMER_EVENT_RESUME)|
1872 			      (1<<SNDRV_TIMER_EVENT_MSTART)|
1873 			      (1<<SNDRV_TIMER_EVENT_MSTOP)|
1874 			      (1<<SNDRV_TIMER_EVENT_MCONTINUE)|
1875 			      (1<<SNDRV_TIMER_EVENT_MPAUSE)|
1876 			      (1<<SNDRV_TIMER_EVENT_MSUSPEND)|
1877 			      (1<<SNDRV_TIMER_EVENT_MRESUME))) {
1878 		err = -EINVAL;
1879 		goto _end;
1880 	}
1881 	snd_timer_stop(tu->timeri);
1882 	spin_lock_irq(&t->lock);
1883 	tu->timeri->flags &= ~(SNDRV_TIMER_IFLG_AUTO|
1884 			       SNDRV_TIMER_IFLG_EXCLUSIVE|
1885 			       SNDRV_TIMER_IFLG_EARLY_EVENT);
1886 	if (params.flags & SNDRV_TIMER_PSFLG_AUTO)
1887 		tu->timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1888 	if (params.flags & SNDRV_TIMER_PSFLG_EXCLUSIVE)
1889 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EXCLUSIVE;
1890 	if (params.flags & SNDRV_TIMER_PSFLG_EARLY_EVENT)
1891 		tu->timeri->flags |= SNDRV_TIMER_IFLG_EARLY_EVENT;
1892 	spin_unlock_irq(&t->lock);
1893 	if (params.queue_size > 0 &&
1894 	    (unsigned int)tu->queue_size != params.queue_size) {
1895 		err = realloc_user_queue(tu, params.queue_size);
1896 		if (err < 0)
1897 			goto _end;
1898 	}
1899 	spin_lock_irq(&tu->qlock);
1900 	tu->qhead = tu->qtail = tu->qused = 0;
1901 	if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
1902 		if (tu->tread) {
1903 			struct snd_timer_tread64 tread;
1904 			memset(&tread, 0, sizeof(tread));
1905 			tread.event = SNDRV_TIMER_EVENT_EARLY;
1906 			tread.tstamp_sec = 0;
1907 			tread.tstamp_nsec = 0;
1908 			tread.val = 0;
1909 			snd_timer_user_append_to_tqueue(tu, &tread);
1910 		} else {
1911 			struct snd_timer_read *r = &tu->queue[0];
1912 			r->resolution = 0;
1913 			r->ticks = 0;
1914 			tu->qused++;
1915 			tu->qtail++;
1916 		}
1917 	}
1918 	tu->filter = params.filter;
1919 	tu->ticks = params.ticks;
1920 	spin_unlock_irq(&tu->qlock);
1921 	err = 0;
1922  _end:
1923 	if (copy_to_user(_params, &params, sizeof(params)))
1924 		return -EFAULT;
1925 	return err;
1926 }
1927 
snd_timer_user_status32(struct file * file,struct snd_timer_status32 __user * _status)1928 static int snd_timer_user_status32(struct file *file,
1929 				   struct snd_timer_status32 __user *_status)
1930  {
1931 	struct snd_timer_user *tu;
1932 	struct snd_timer_status32 status;
1933 
1934 	tu = file->private_data;
1935 	if (!tu->timeri)
1936 		return -EBADFD;
1937 	memset(&status, 0, sizeof(status));
1938 	status.tstamp_sec = tu->tstamp.tv_sec;
1939 	status.tstamp_nsec = tu->tstamp.tv_nsec;
1940 	status.resolution = snd_timer_resolution(tu->timeri);
1941 	status.lost = tu->timeri->lost;
1942 	status.overrun = tu->overrun;
1943 	spin_lock_irq(&tu->qlock);
1944 	status.queue = tu->qused;
1945 	spin_unlock_irq(&tu->qlock);
1946 	if (copy_to_user(_status, &status, sizeof(status)))
1947 		return -EFAULT;
1948 	return 0;
1949 }
1950 
snd_timer_user_status64(struct file * file,struct snd_timer_status64 __user * _status)1951 static int snd_timer_user_status64(struct file *file,
1952 				   struct snd_timer_status64 __user *_status)
1953 {
1954 	struct snd_timer_user *tu;
1955 	struct snd_timer_status64 status;
1956 
1957 	tu = file->private_data;
1958 	if (!tu->timeri)
1959 		return -EBADFD;
1960 	memset(&status, 0, sizeof(status));
1961 	status.tstamp_sec = tu->tstamp.tv_sec;
1962 	status.tstamp_nsec = tu->tstamp.tv_nsec;
1963 	status.resolution = snd_timer_resolution(tu->timeri);
1964 	status.lost = tu->timeri->lost;
1965 	status.overrun = tu->overrun;
1966 	spin_lock_irq(&tu->qlock);
1967 	status.queue = tu->qused;
1968 	spin_unlock_irq(&tu->qlock);
1969 	if (copy_to_user(_status, &status, sizeof(status)))
1970 		return -EFAULT;
1971 	return 0;
1972 }
1973 
snd_timer_user_start(struct file * file)1974 static int snd_timer_user_start(struct file *file)
1975 {
1976 	int err;
1977 	struct snd_timer_user *tu;
1978 
1979 	tu = file->private_data;
1980 	if (!tu->timeri)
1981 		return -EBADFD;
1982 	snd_timer_stop(tu->timeri);
1983 	tu->timeri->lost = 0;
1984 	tu->last_resolution = 0;
1985 	err = snd_timer_start(tu->timeri, tu->ticks);
1986 	if (err < 0)
1987 		return err;
1988 	return 0;
1989 }
1990 
snd_timer_user_stop(struct file * file)1991 static int snd_timer_user_stop(struct file *file)
1992 {
1993 	int err;
1994 	struct snd_timer_user *tu;
1995 
1996 	tu = file->private_data;
1997 	if (!tu->timeri)
1998 		return -EBADFD;
1999 	err = snd_timer_stop(tu->timeri);
2000 	if (err < 0)
2001 		return err;
2002 	return 0;
2003 }
2004 
snd_timer_user_continue(struct file * file)2005 static int snd_timer_user_continue(struct file *file)
2006 {
2007 	int err;
2008 	struct snd_timer_user *tu;
2009 
2010 	tu = file->private_data;
2011 	if (!tu->timeri)
2012 		return -EBADFD;
2013 	/* start timer instead of continue if it's not used before */
2014 	if (!(tu->timeri->flags & SNDRV_TIMER_IFLG_PAUSED))
2015 		return snd_timer_user_start(file);
2016 	tu->timeri->lost = 0;
2017 	err = snd_timer_continue(tu->timeri);
2018 	if (err < 0)
2019 		return err;
2020 	return 0;
2021 }
2022 
snd_timer_user_pause(struct file * file)2023 static int snd_timer_user_pause(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 	err = snd_timer_pause(tu->timeri);
2032 	if (err < 0)
2033 		return err;
2034 	return 0;
2035 }
2036 
snd_timer_user_tread(void __user * argp,struct snd_timer_user * tu,unsigned int cmd,bool compat)2037 static int snd_timer_user_tread(void __user *argp, struct snd_timer_user *tu,
2038 				unsigned int cmd, bool compat)
2039 {
2040 	int __user *p = argp;
2041 	int xarg, old_tread;
2042 
2043 	if (tu->timeri)	/* too late */
2044 		return -EBUSY;
2045 	if (get_user(xarg, p))
2046 		return -EFAULT;
2047 
2048 	old_tread = tu->tread;
2049 
2050 	if (!xarg)
2051 		tu->tread = TREAD_FORMAT_NONE;
2052 	else if (cmd == SNDRV_TIMER_IOCTL_TREAD64 ||
2053 		 (IS_ENABLED(CONFIG_64BIT) && !compat))
2054 		tu->tread = TREAD_FORMAT_TIME64;
2055 	else
2056 		tu->tread = TREAD_FORMAT_TIME32;
2057 
2058 	if (tu->tread != old_tread &&
2059 	    realloc_user_queue(tu, tu->queue_size) < 0) {
2060 		tu->tread = old_tread;
2061 		return -ENOMEM;
2062 	}
2063 
2064 	return 0;
2065 }
2066 
2067 enum {
2068 	SNDRV_TIMER_IOCTL_START_OLD = _IO('T', 0x20),
2069 	SNDRV_TIMER_IOCTL_STOP_OLD = _IO('T', 0x21),
2070 	SNDRV_TIMER_IOCTL_CONTINUE_OLD = _IO('T', 0x22),
2071 	SNDRV_TIMER_IOCTL_PAUSE_OLD = _IO('T', 0x23),
2072 };
2073 
__snd_timer_user_ioctl(struct file * file,unsigned int cmd,unsigned long arg,bool compat)2074 static long __snd_timer_user_ioctl(struct file *file, unsigned int cmd,
2075 				 unsigned long arg, bool compat)
2076 {
2077 	struct snd_timer_user *tu;
2078 	void __user *argp = (void __user *)arg;
2079 	int __user *p = argp;
2080 
2081 	tu = file->private_data;
2082 	switch (cmd) {
2083 	case SNDRV_TIMER_IOCTL_PVERSION:
2084 		return put_user(SNDRV_TIMER_VERSION, p) ? -EFAULT : 0;
2085 	case SNDRV_TIMER_IOCTL_NEXT_DEVICE:
2086 		return snd_timer_user_next_device(argp);
2087 	case SNDRV_TIMER_IOCTL_TREAD_OLD:
2088 	case SNDRV_TIMER_IOCTL_TREAD64:
2089 		return snd_timer_user_tread(argp, tu, cmd, compat);
2090 	case SNDRV_TIMER_IOCTL_GINFO:
2091 		return snd_timer_user_ginfo(file, argp);
2092 	case SNDRV_TIMER_IOCTL_GPARAMS:
2093 		return snd_timer_user_gparams(file, argp);
2094 	case SNDRV_TIMER_IOCTL_GSTATUS:
2095 		return snd_timer_user_gstatus(file, argp);
2096 	case SNDRV_TIMER_IOCTL_SELECT:
2097 		return snd_timer_user_tselect(file, argp);
2098 	case SNDRV_TIMER_IOCTL_INFO:
2099 		return snd_timer_user_info(file, argp);
2100 	case SNDRV_TIMER_IOCTL_PARAMS:
2101 		return snd_timer_user_params(file, argp);
2102 	case SNDRV_TIMER_IOCTL_STATUS32:
2103 		return snd_timer_user_status32(file, argp);
2104 	case SNDRV_TIMER_IOCTL_STATUS64:
2105 		return snd_timer_user_status64(file, argp);
2106 	case SNDRV_TIMER_IOCTL_START:
2107 	case SNDRV_TIMER_IOCTL_START_OLD:
2108 		return snd_timer_user_start(file);
2109 	case SNDRV_TIMER_IOCTL_STOP:
2110 	case SNDRV_TIMER_IOCTL_STOP_OLD:
2111 		return snd_timer_user_stop(file);
2112 	case SNDRV_TIMER_IOCTL_CONTINUE:
2113 	case SNDRV_TIMER_IOCTL_CONTINUE_OLD:
2114 		return snd_timer_user_continue(file);
2115 	case SNDRV_TIMER_IOCTL_PAUSE:
2116 	case SNDRV_TIMER_IOCTL_PAUSE_OLD:
2117 		return snd_timer_user_pause(file);
2118 	}
2119 	return -ENOTTY;
2120 }
2121 
snd_timer_user_ioctl(struct file * file,unsigned int cmd,unsigned long arg)2122 static long snd_timer_user_ioctl(struct file *file, unsigned int cmd,
2123 				 unsigned long arg)
2124 {
2125 	struct snd_timer_user *tu = file->private_data;
2126 	long ret;
2127 
2128 	mutex_lock(&tu->ioctl_lock);
2129 	ret = __snd_timer_user_ioctl(file, cmd, arg, false);
2130 	mutex_unlock(&tu->ioctl_lock);
2131 	return ret;
2132 }
2133 
snd_timer_user_fasync(int fd,struct file * file,int on)2134 static int snd_timer_user_fasync(int fd, struct file * file, int on)
2135 {
2136 	struct snd_timer_user *tu;
2137 
2138 	tu = file->private_data;
2139 	return snd_fasync_helper(fd, file, on, &tu->fasync);
2140 }
2141 
snd_timer_user_read(struct file * file,char __user * buffer,size_t count,loff_t * offset)2142 static ssize_t snd_timer_user_read(struct file *file, char __user *buffer,
2143 				   size_t count, loff_t *offset)
2144 {
2145 	struct snd_timer_tread64 *tread;
2146 	struct snd_timer_tread32 tread32;
2147 	struct snd_timer_user *tu;
2148 	long result = 0, unit;
2149 	int qhead;
2150 	int err = 0;
2151 
2152 	tu = file->private_data;
2153 	switch (tu->tread) {
2154 	case TREAD_FORMAT_TIME64:
2155 		unit = sizeof(struct snd_timer_tread64);
2156 		break;
2157 	case TREAD_FORMAT_TIME32:
2158 		unit = sizeof(struct snd_timer_tread32);
2159 		break;
2160 	case TREAD_FORMAT_NONE:
2161 		unit = sizeof(struct snd_timer_read);
2162 		break;
2163 	default:
2164 		WARN_ONCE(1, "Corrupt snd_timer_user\n");
2165 		return -ENOTSUPP;
2166 	}
2167 
2168 	mutex_lock(&tu->ioctl_lock);
2169 	spin_lock_irq(&tu->qlock);
2170 	while ((long)count - result >= unit) {
2171 		while (!tu->qused) {
2172 			wait_queue_entry_t wait;
2173 
2174 			if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
2175 				err = -EAGAIN;
2176 				goto _error;
2177 			}
2178 
2179 			set_current_state(TASK_INTERRUPTIBLE);
2180 			init_waitqueue_entry(&wait, current);
2181 			add_wait_queue(&tu->qchange_sleep, &wait);
2182 
2183 			spin_unlock_irq(&tu->qlock);
2184 			mutex_unlock(&tu->ioctl_lock);
2185 			schedule();
2186 			mutex_lock(&tu->ioctl_lock);
2187 			spin_lock_irq(&tu->qlock);
2188 
2189 			remove_wait_queue(&tu->qchange_sleep, &wait);
2190 
2191 			if (tu->disconnected) {
2192 				err = -ENODEV;
2193 				goto _error;
2194 			}
2195 			if (signal_pending(current)) {
2196 				err = -ERESTARTSYS;
2197 				goto _error;
2198 			}
2199 		}
2200 
2201 		qhead = tu->qhead++;
2202 		tu->qhead %= tu->queue_size;
2203 		tu->qused--;
2204 		spin_unlock_irq(&tu->qlock);
2205 
2206 		tread = &tu->tqueue[qhead];
2207 
2208 		switch (tu->tread) {
2209 		case TREAD_FORMAT_TIME64:
2210 			if (copy_to_user(buffer, tread,
2211 					 sizeof(struct snd_timer_tread64)))
2212 				err = -EFAULT;
2213 			break;
2214 		case TREAD_FORMAT_TIME32:
2215 			memset(&tread32, 0, sizeof(tread32));
2216 			tread32 = (struct snd_timer_tread32) {
2217 				.event = tread->event,
2218 				.tstamp_sec = tread->tstamp_sec,
2219 				.tstamp_nsec = tread->tstamp_nsec,
2220 				.val = tread->val,
2221 			};
2222 
2223 			if (copy_to_user(buffer, &tread32, sizeof(tread32)))
2224 				err = -EFAULT;
2225 			break;
2226 		case TREAD_FORMAT_NONE:
2227 			if (copy_to_user(buffer, &tu->queue[qhead],
2228 					 sizeof(struct snd_timer_read)))
2229 				err = -EFAULT;
2230 			break;
2231 		default:
2232 			err = -ENOTSUPP;
2233 			break;
2234 		}
2235 
2236 		spin_lock_irq(&tu->qlock);
2237 		if (err < 0)
2238 			goto _error;
2239 		result += unit;
2240 		buffer += unit;
2241 	}
2242  _error:
2243 	spin_unlock_irq(&tu->qlock);
2244 	mutex_unlock(&tu->ioctl_lock);
2245 	return result > 0 ? result : err;
2246 }
2247 
snd_timer_user_poll(struct file * file,poll_table * wait)2248 static __poll_t snd_timer_user_poll(struct file *file, poll_table * wait)
2249 {
2250         __poll_t mask;
2251         struct snd_timer_user *tu;
2252 
2253         tu = file->private_data;
2254 
2255         poll_wait(file, &tu->qchange_sleep, wait);
2256 
2257 	mask = 0;
2258 	spin_lock_irq(&tu->qlock);
2259 	if (tu->qused)
2260 		mask |= EPOLLIN | EPOLLRDNORM;
2261 	if (tu->disconnected)
2262 		mask |= EPOLLERR;
2263 	spin_unlock_irq(&tu->qlock);
2264 
2265 	return mask;
2266 }
2267 
2268 #ifdef CONFIG_COMPAT
2269 #include "timer_compat.c"
2270 #else
2271 #define snd_timer_user_ioctl_compat	NULL
2272 #endif
2273 
2274 static const struct file_operations snd_timer_f_ops =
2275 {
2276 	.owner =	THIS_MODULE,
2277 	.read =		snd_timer_user_read,
2278 	.open =		snd_timer_user_open,
2279 	.release =	snd_timer_user_release,
2280 	.llseek =	no_llseek,
2281 	.poll =		snd_timer_user_poll,
2282 	.unlocked_ioctl =	snd_timer_user_ioctl,
2283 	.compat_ioctl =	snd_timer_user_ioctl_compat,
2284 	.fasync = 	snd_timer_user_fasync,
2285 };
2286 
2287 /* unregister the system timer */
snd_timer_free_all(void)2288 static void snd_timer_free_all(void)
2289 {
2290 	struct snd_timer *timer, *n;
2291 
2292 	list_for_each_entry_safe(timer, n, &snd_timer_list, device_list)
2293 		snd_timer_free(timer);
2294 }
2295 
2296 static struct device timer_dev;
2297 
2298 /*
2299  *  ENTRY functions
2300  */
2301 
alsa_timer_init(void)2302 static int __init alsa_timer_init(void)
2303 {
2304 	int err;
2305 
2306 	snd_device_initialize(&timer_dev, NULL);
2307 	dev_set_name(&timer_dev, "timer");
2308 
2309 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
2310 	snd_oss_info_register(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1,
2311 			      "system timer");
2312 #endif
2313 
2314 	err = snd_timer_register_system();
2315 	if (err < 0) {
2316 		pr_err("ALSA: unable to register system timer (%i)\n", err);
2317 		goto put_timer;
2318 	}
2319 
2320 	err = snd_register_device(SNDRV_DEVICE_TYPE_TIMER, NULL, 0,
2321 				  &snd_timer_f_ops, NULL, &timer_dev);
2322 	if (err < 0) {
2323 		pr_err("ALSA: unable to register timer device (%i)\n", err);
2324 		snd_timer_free_all();
2325 		goto put_timer;
2326 	}
2327 
2328 	snd_timer_proc_init();
2329 	return 0;
2330 
2331 put_timer:
2332 	put_device(&timer_dev);
2333 	return err;
2334 }
2335 
alsa_timer_exit(void)2336 static void __exit alsa_timer_exit(void)
2337 {
2338 	snd_unregister_device(&timer_dev);
2339 	snd_timer_free_all();
2340 	put_device(&timer_dev);
2341 	snd_timer_proc_done();
2342 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
2343 	snd_oss_info_unregister(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1);
2344 #endif
2345 }
2346 
2347 module_init(alsa_timer_init)
2348 module_exit(alsa_timer_exit)
2349