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TOMOYO Linux Cross Reference
Linux/sound/core/timer.c

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  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 fasync_struct *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  */
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 
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  */
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 
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 */
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  */
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  */
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  */
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  */
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  */
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 
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 
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 
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 */
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 */
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 */
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 */
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  */
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  */
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  */
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  */
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  */
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 */
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 */
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  */
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  */
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 
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 
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 
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 
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 
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 
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  */
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 
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 
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 
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 
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 
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 
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 
1211 static void snd_timer_free_system(struct snd_timer *timer)
1212 {
1213         kfree(timer->private_data);
1214 }
1215 
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 
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 
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 
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 
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         kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1349         wake_up(&tu->qchange_sleep);
1350 }
1351 
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 
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         kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1387         wake_up(&tu->qchange_sleep);
1388 }
1389 
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 
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         kill_fasync(&tu->fasync, SIGIO, POLL_IN);
1457         wake_up(&tu->qchange_sleep);
1458 }
1459 
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 
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 
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                 kfree(tu->queue);
1525                 kfree(tu->tqueue);
1526                 kfree(tu);
1527         }
1528         return 0;
1529 }
1530 
1531 static void snd_timer_user_zero_id(struct snd_timer_id *id)
1532 {
1533         id->dev_class = SNDRV_TIMER_CLASS_NONE;
1534         id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1535         id->card = -1;
1536         id->device = -1;
1537         id->subdevice = -1;
1538 }
1539 
1540 static void snd_timer_user_copy_id(struct snd_timer_id *id, struct snd_timer *timer)
1541 {
1542         id->dev_class = timer->tmr_class;
1543         id->dev_sclass = SNDRV_TIMER_SCLASS_NONE;
1544         id->card = timer->card ? timer->card->number : -1;
1545         id->device = timer->tmr_device;
1546         id->subdevice = timer->tmr_subdevice;
1547 }
1548 
1549 static int snd_timer_user_next_device(struct snd_timer_id __user *_tid)
1550 {
1551         struct snd_timer_id id;
1552         struct snd_timer *timer;
1553         struct list_head *p;
1554 
1555         if (copy_from_user(&id, _tid, sizeof(id)))
1556                 return -EFAULT;
1557         mutex_lock(&register_mutex);
1558         if (id.dev_class < 0) {         /* first item */
1559                 if (list_empty(&snd_timer_list))
1560                         snd_timer_user_zero_id(&id);
1561                 else {
1562                         timer = list_entry(snd_timer_list.next,
1563                                            struct snd_timer, device_list);
1564                         snd_timer_user_copy_id(&id, timer);
1565                 }
1566         } else {
1567                 switch (id.dev_class) {
1568                 case SNDRV_TIMER_CLASS_GLOBAL:
1569                         id.device = id.device < 0 ? 0 : id.device + 1;
1570                         list_for_each(p, &snd_timer_list) {
1571                                 timer = list_entry(p, struct snd_timer, device_list);
1572                                 if (timer->tmr_class > SNDRV_TIMER_CLASS_GLOBAL) {
1573                                         snd_timer_user_copy_id(&id, timer);
1574                                         break;
1575                                 }
1576                                 if (timer->tmr_device >= id.device) {
1577                                         snd_timer_user_copy_id(&id, timer);
1578                                         break;
1579                                 }
1580                         }
1581                         if (p == &snd_timer_list)
1582                                 snd_timer_user_zero_id(&id);
1583                         break;
1584                 case SNDRV_TIMER_CLASS_CARD:
1585                 case SNDRV_TIMER_CLASS_PCM:
1586                         if (id.card < 0) {
1587                                 id.card = 0;
1588                         } else {
1589                                 if (id.device < 0) {
1590                                         id.device = 0;
1591                                 } else {
1592                                         if (id.subdevice < 0)
1593                                                 id.subdevice = 0;
1594                                         else if (id.subdevice < INT_MAX)
1595                                                 id.subdevice++;
1596                                 }
1597                         }
1598                         list_for_each(p, &snd_timer_list) {
1599                                 timer = list_entry(p, struct snd_timer, device_list);
1600                                 if (timer->tmr_class > id.dev_class) {
1601                                         snd_timer_user_copy_id(&id, timer);
1602                                         break;
1603                                 }
1604                                 if (timer->tmr_class < id.dev_class)
1605                                         continue;
1606                                 if (timer->card->number > id.card) {
1607                                         snd_timer_user_copy_id(&id, timer);
1608                                         break;
1609                                 }
1610                                 if (timer->card->number < id.card)
1611                                         continue;
1612                                 if (timer->tmr_device > id.device) {
1613                                         snd_timer_user_copy_id(&id, timer);
1614                                         break;
1615                                 }
1616                                 if (timer->tmr_device < id.device)
1617                                         continue;
1618                                 if (timer->tmr_subdevice > id.subdevice) {
1619                                         snd_timer_user_copy_id(&id, timer);
1620                                         break;
1621                                 }
1622                                 if (timer->tmr_subdevice < id.subdevice)
1623                                         continue;
1624                                 snd_timer_user_copy_id(&id, timer);
1625                                 break;
1626                         }
1627                         if (p == &snd_timer_list)
1628                                 snd_timer_user_zero_id(&id);
1629                         break;
1630                 default:
1631                         snd_timer_user_zero_id(&id);
1632                 }
1633         }
1634         mutex_unlock(&register_mutex);
1635         if (copy_to_user(_tid, &id, sizeof(*_tid)))
1636                 return -EFAULT;
1637         return 0;
1638 }
1639 
1640 static int snd_timer_user_ginfo(struct file *file,
1641                                 struct snd_timer_ginfo __user *_ginfo)
1642 {
1643         struct snd_timer_ginfo *ginfo;
1644         struct snd_timer_id tid;
1645         struct snd_timer *t;
1646         struct list_head *p;
1647         int err = 0;
1648 
1649         ginfo = memdup_user(_ginfo, sizeof(*ginfo));
1650         if (IS_ERR(ginfo))
1651                 return PTR_ERR(ginfo);
1652 
1653         tid = ginfo->tid;
1654         memset(ginfo, 0, sizeof(*ginfo));
1655         ginfo->tid = tid;
1656         mutex_lock(&register_mutex);
1657         t = snd_timer_find(&tid);
1658         if (t != NULL) {
1659                 ginfo->card = t->card ? t->card->number : -1;
1660                 if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1661                         ginfo->flags |= SNDRV_TIMER_FLG_SLAVE;
1662                 strscpy(ginfo->id, t->id, sizeof(ginfo->id));
1663                 strscpy(ginfo->name, t->name, sizeof(ginfo->name));
1664                 ginfo->resolution = t->hw.resolution;
1665                 if (t->hw.resolution_min > 0) {
1666                         ginfo->resolution_min = t->hw.resolution_min;
1667                         ginfo->resolution_max = t->hw.resolution_max;
1668                 }
1669                 list_for_each(p, &t->open_list_head) {
1670                         ginfo->clients++;
1671                 }
1672         } else {
1673                 err = -ENODEV;
1674         }
1675         mutex_unlock(&register_mutex);
1676         if (err >= 0 && copy_to_user(_ginfo, ginfo, sizeof(*ginfo)))
1677                 err = -EFAULT;
1678         kfree(ginfo);
1679         return err;
1680 }
1681 
1682 static int timer_set_gparams(struct snd_timer_gparams *gparams)
1683 {
1684         struct snd_timer *t;
1685         int err;
1686 
1687         mutex_lock(&register_mutex);
1688         t = snd_timer_find(&gparams->tid);
1689         if (!t) {
1690                 err = -ENODEV;
1691                 goto _error;
1692         }
1693         if (!list_empty(&t->open_list_head)) {
1694                 err = -EBUSY;
1695                 goto _error;
1696         }
1697         if (!t->hw.set_period) {
1698                 err = -ENOSYS;
1699                 goto _error;
1700         }
1701         err = t->hw.set_period(t, gparams->period_num, gparams->period_den);
1702 _error:
1703         mutex_unlock(&register_mutex);
1704         return err;
1705 }
1706 
1707 static int snd_timer_user_gparams(struct file *file,
1708                                   struct snd_timer_gparams __user *_gparams)
1709 {
1710         struct snd_timer_gparams gparams;
1711 
1712         if (copy_from_user(&gparams, _gparams, sizeof(gparams)))
1713                 return -EFAULT;
1714         return timer_set_gparams(&gparams);
1715 }
1716 
1717 static int snd_timer_user_gstatus(struct file *file,
1718                                   struct snd_timer_gstatus __user *_gstatus)
1719 {
1720         struct snd_timer_gstatus gstatus;
1721         struct snd_timer_id tid;
1722         struct snd_timer *t;
1723         int err = 0;
1724 
1725         if (copy_from_user(&gstatus, _gstatus, sizeof(gstatus)))
1726                 return -EFAULT;
1727         tid = gstatus.tid;
1728         memset(&gstatus, 0, sizeof(gstatus));
1729         gstatus.tid = tid;
1730         mutex_lock(&register_mutex);
1731         t = snd_timer_find(&tid);
1732         if (t != NULL) {
1733                 spin_lock_irq(&t->lock);
1734                 gstatus.resolution = snd_timer_hw_resolution(t);
1735                 if (t->hw.precise_resolution) {
1736                         t->hw.precise_resolution(t, &gstatus.resolution_num,
1737                                                  &gstatus.resolution_den);
1738                 } else {
1739                         gstatus.resolution_num = gstatus.resolution;
1740                         gstatus.resolution_den = 1000000000uL;
1741                 }
1742                 spin_unlock_irq(&t->lock);
1743         } else {
1744                 err = -ENODEV;
1745         }
1746         mutex_unlock(&register_mutex);
1747         if (err >= 0 && copy_to_user(_gstatus, &gstatus, sizeof(gstatus)))
1748                 err = -EFAULT;
1749         return err;
1750 }
1751 
1752 static int snd_timer_user_tselect(struct file *file,
1753                                   struct snd_timer_select __user *_tselect)
1754 {
1755         struct snd_timer_user *tu;
1756         struct snd_timer_select tselect;
1757         char str[32];
1758         int err = 0;
1759 
1760         tu = file->private_data;
1761         if (tu->timeri) {
1762                 snd_timer_close(tu->timeri);
1763                 snd_timer_instance_free(tu->timeri);
1764                 tu->timeri = NULL;
1765         }
1766         if (copy_from_user(&tselect, _tselect, sizeof(tselect))) {
1767                 err = -EFAULT;
1768                 goto __err;
1769         }
1770         sprintf(str, "application %i", current->pid);
1771         if (tselect.id.dev_class != SNDRV_TIMER_CLASS_SLAVE)
1772                 tselect.id.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION;
1773         tu->timeri = snd_timer_instance_new(str);
1774         if (!tu->timeri) {
1775                 err = -ENOMEM;
1776                 goto __err;
1777         }
1778 
1779         tu->timeri->flags |= SNDRV_TIMER_IFLG_FAST;
1780         tu->timeri->callback = tu->tread
1781                         ? snd_timer_user_tinterrupt : snd_timer_user_interrupt;
1782         tu->timeri->ccallback = snd_timer_user_ccallback;
1783         tu->timeri->callback_data = (void *)tu;
1784         tu->timeri->disconnect = snd_timer_user_disconnect;
1785 
1786         err = snd_timer_open(tu->timeri, &tselect.id, current->pid);
1787         if (err < 0) {
1788                 snd_timer_instance_free(tu->timeri);
1789                 tu->timeri = NULL;
1790         }
1791 
1792       __err:
1793         return err;
1794 }
1795 
1796 static int snd_timer_user_info(struct file *file,
1797                                struct snd_timer_info __user *_info)
1798 {
1799         struct snd_timer_user *tu;
1800         struct snd_timer_info *info;
1801         struct snd_timer *t;
1802         int err = 0;
1803 
1804         tu = file->private_data;
1805         if (!tu->timeri)
1806                 return -EBADFD;
1807         t = tu->timeri->timer;
1808         if (!t)
1809                 return -EBADFD;
1810 
1811         info = kzalloc(sizeof(*info), GFP_KERNEL);
1812         if (! info)
1813                 return -ENOMEM;
1814         info->card = t->card ? t->card->number : -1;
1815         if (t->hw.flags & SNDRV_TIMER_HW_SLAVE)
1816                 info->flags |= SNDRV_TIMER_FLG_SLAVE;
1817         strscpy(info->id, t->id, sizeof(info->id));
1818         strscpy(info->name, t->name, sizeof(info->name));
1819         info->resolution = t->hw.resolution;
1820         if (copy_to_user(_info, info, sizeof(*_info)))
1821                 err = -EFAULT;
1822         kfree(info);
1823         return err;
1824 }
1825 
1826 static int snd_timer_user_params(struct file *file,
1827                                  struct snd_timer_params __user *_params)
1828 {
1829         struct snd_timer_user *tu;
1830         struct snd_timer_params params;
1831         struct snd_timer *t;
1832         int err;
1833 
1834         tu = file->private_data;
1835         if (!tu->timeri)
1836                 return -EBADFD;
1837         t = tu->timeri->timer;
1838         if (!t)
1839                 return -EBADFD;
1840         if (copy_from_user(&params, _params, sizeof(params)))
1841                 return -EFAULT;
1842         if (!(t->hw.flags & SNDRV_TIMER_HW_SLAVE)) {
1843                 u64 resolution;
1844 
1845                 if (params.ticks < 1) {
1846                         err = -EINVAL;
1847                         goto _end;
1848                 }
1849 
1850                 /* Don't allow resolution less than 1ms */
1851                 resolution = snd_timer_resolution(tu->timeri);
1852                 resolution *= params.ticks;
1853                 if (resolution < 1000000) {
1854                         err = -EINVAL;
1855                         goto _end;
1856                 }
1857         }
1858         if (params.queue_size > 0 &&
1859             (params.queue_size < 32 || params.queue_size > 1024)) {
1860                 err = -EINVAL;
1861                 goto _end;
1862         }
1863         if (params.filter & ~((1<<SNDRV_TIMER_EVENT_RESOLUTION)|
1864                               (1<<SNDRV_TIMER_EVENT_TICK)|
1865                               (1<<SNDRV_TIMER_EVENT_START)|
1866                               (1<<SNDRV_TIMER_EVENT_STOP)|
1867                               (1<<SNDRV_TIMER_EVENT_CONTINUE)|
1868                               (1<<SNDRV_TIMER_EVENT_PAUSE)|
1869                               (1<<SNDRV_TIMER_EVENT_SUSPEND)|
1870                               (1<<SNDRV_TIMER_EVENT_RESUME)|
1871                               (1<<SNDRV_TIMER_EVENT_MSTART)|
1872                               (1<<SNDRV_TIMER_EVENT_MSTOP)|
1873                               (1<<SNDRV_TIMER_EVENT_MCONTINUE)|
1874                               (1<<SNDRV_TIMER_EVENT_MPAUSE)|
1875                               (1<<SNDRV_TIMER_EVENT_MSUSPEND)|
1876                               (1<<SNDRV_TIMER_EVENT_MRESUME))) {
1877                 err = -EINVAL;
1878                 goto _end;
1879         }
1880         snd_timer_stop(tu->timeri);
1881         spin_lock_irq(&t->lock);
1882         tu->timeri->flags &= ~(SNDRV_TIMER_IFLG_AUTO|
1883                                SNDRV_TIMER_IFLG_EXCLUSIVE|
1884                                SNDRV_TIMER_IFLG_EARLY_EVENT);
1885         if (params.flags & SNDRV_TIMER_PSFLG_AUTO)
1886                 tu->timeri->flags |= SNDRV_TIMER_IFLG_AUTO;
1887         if (params.flags & SNDRV_TIMER_PSFLG_EXCLUSIVE)
1888                 tu->timeri->flags |= SNDRV_TIMER_IFLG_EXCLUSIVE;
1889         if (params.flags & SNDRV_TIMER_PSFLG_EARLY_EVENT)
1890                 tu->timeri->flags |= SNDRV_TIMER_IFLG_EARLY_EVENT;
1891         spin_unlock_irq(&t->lock);
1892         if (params.queue_size > 0 &&
1893             (unsigned int)tu->queue_size != params.queue_size) {
1894                 err = realloc_user_queue(tu, params.queue_size);
1895                 if (err < 0)
1896                         goto _end;
1897         }
1898         spin_lock_irq(&tu->qlock);
1899         tu->qhead = tu->qtail = tu->qused = 0;
1900         if (tu->timeri->flags & SNDRV_TIMER_IFLG_EARLY_EVENT) {
1901                 if (tu->tread) {
1902                         struct snd_timer_tread64 tread;
1903                         memset(&tread, 0, sizeof(tread));
1904                         tread.event = SNDRV_TIMER_EVENT_EARLY;
1905                         tread.tstamp_sec = 0;
1906                         tread.tstamp_nsec = 0;
1907                         tread.val = 0;
1908                         snd_timer_user_append_to_tqueue(tu, &tread);
1909                 } else {
1910                         struct snd_timer_read *r = &tu->queue[0];
1911                         r->resolution = 0;
1912                         r->ticks = 0;
1913                         tu->qused++;
1914                         tu->qtail++;
1915                 }
1916         }
1917         tu->filter = params.filter;
1918         tu->ticks = params.ticks;
1919         spin_unlock_irq(&tu->qlock);
1920         err = 0;
1921  _end:
1922         if (copy_to_user(_params, &params, sizeof(params)))
1923                 return -EFAULT;
1924         return err;
1925 }
1926 
1927 static int snd_timer_user_status32(struct file *file,
1928                                    struct snd_timer_status32 __user *_status)
1929  {
1930         struct snd_timer_user *tu;
1931         struct snd_timer_status32 status;
1932 
1933         tu = file->private_data;
1934         if (!tu->timeri)
1935                 return -EBADFD;
1936         memset(&status, 0, sizeof(status));
1937         status.tstamp_sec = tu->tstamp.tv_sec;
1938         status.tstamp_nsec = tu->tstamp.tv_nsec;
1939         status.resolution = snd_timer_resolution(tu->timeri);
1940         status.lost = tu->timeri->lost;
1941         status.overrun = tu->overrun;
1942         spin_lock_irq(&tu->qlock);
1943         status.queue = tu->qused;
1944         spin_unlock_irq(&tu->qlock);
1945         if (copy_to_user(_status, &status, sizeof(status)))
1946                 return -EFAULT;
1947         return 0;
1948 }
1949 
1950 static int snd_timer_user_status64(struct file *file,
1951                                    struct snd_timer_status64 __user *_status)
1952 {
1953         struct snd_timer_user *tu;
1954         struct snd_timer_status64 status;
1955 
1956         tu = file->private_data;
1957         if (!tu->timeri)
1958                 return -EBADFD;
1959         memset(&status, 0, sizeof(status));
1960         status.tstamp_sec = tu->tstamp.tv_sec;
1961         status.tstamp_nsec = tu->tstamp.tv_nsec;
1962         status.resolution = snd_timer_resolution(tu->timeri);
1963         status.lost = tu->timeri->lost;
1964         status.overrun = tu->overrun;
1965         spin_lock_irq(&tu->qlock);
1966         status.queue = tu->qused;
1967         spin_unlock_irq(&tu->qlock);
1968         if (copy_to_user(_status, &status, sizeof(status)))
1969                 return -EFAULT;
1970         return 0;
1971 }
1972 
1973 static int snd_timer_user_start(struct file *file)
1974 {
1975         int err;
1976         struct snd_timer_user *tu;
1977 
1978         tu = file->private_data;
1979         if (!tu->timeri)
1980                 return -EBADFD;
1981         snd_timer_stop(tu->timeri);
1982         tu->timeri->lost = 0;
1983         tu->last_resolution = 0;
1984         err = snd_timer_start(tu->timeri, tu->ticks);
1985         if (err < 0)
1986                 return err;
1987         return 0;
1988 }
1989 
1990 static int snd_timer_user_stop(struct file *file)
1991 {
1992         int err;
1993         struct snd_timer_user *tu;
1994 
1995         tu = file->private_data;
1996         if (!tu->timeri)
1997                 return -EBADFD;
1998         err = snd_timer_stop(tu->timeri);
1999         if (err < 0)
2000                 return err;
2001         return 0;
2002 }
2003 
2004 static int snd_timer_user_continue(struct file *file)
2005 {
2006         int err;
2007         struct snd_timer_user *tu;
2008 
2009         tu = file->private_data;
2010         if (!tu->timeri)
2011                 return -EBADFD;
2012         /* start timer instead of continue if it's not used before */
2013         if (!(tu->timeri->flags & SNDRV_TIMER_IFLG_PAUSED))
2014                 return snd_timer_user_start(file);
2015         tu->timeri->lost = 0;
2016         err = snd_timer_continue(tu->timeri);
2017         if (err < 0)
2018                 return err;
2019         return 0;
2020 }
2021 
2022 static int snd_timer_user_pause(struct file *file)
2023 {
2024         int err;
2025         struct snd_timer_user *tu;
2026 
2027         tu = file->private_data;
2028         if (!tu->timeri)
2029                 return -EBADFD;
2030         err = snd_timer_pause(tu->timeri);
2031         if (err < 0)
2032                 return err;
2033         return 0;
2034 }
2035 
2036 static int snd_timer_user_tread(void __user *argp, struct snd_timer_user *tu,
2037                                 unsigned int cmd, bool compat)
2038 {
2039         int __user *p = argp;
2040         int xarg, old_tread;
2041 
2042         if (tu->timeri) /* too late */
2043                 return -EBUSY;
2044         if (get_user(xarg, p))
2045                 return -EFAULT;
2046 
2047         old_tread = tu->tread;
2048 
2049         if (!xarg)
2050                 tu->tread = TREAD_FORMAT_NONE;
2051         else if (cmd == SNDRV_TIMER_IOCTL_TREAD64 ||
2052                  (IS_ENABLED(CONFIG_64BIT) && !compat))
2053                 tu->tread = TREAD_FORMAT_TIME64;
2054         else
2055                 tu->tread = TREAD_FORMAT_TIME32;
2056 
2057         if (tu->tread != old_tread &&
2058             realloc_user_queue(tu, tu->queue_size) < 0) {
2059                 tu->tread = old_tread;
2060                 return -ENOMEM;
2061         }
2062 
2063         return 0;
2064 }
2065 
2066 enum {
2067         SNDRV_TIMER_IOCTL_START_OLD = _IO('T', 0x20),
2068         SNDRV_TIMER_IOCTL_STOP_OLD = _IO('T', 0x21),
2069         SNDRV_TIMER_IOCTL_CONTINUE_OLD = _IO('T', 0x22),
2070         SNDRV_TIMER_IOCTL_PAUSE_OLD = _IO('T', 0x23),
2071 };
2072 
2073 static long __snd_timer_user_ioctl(struct file *file, unsigned int cmd,
2074                                  unsigned long arg, bool compat)
2075 {
2076         struct snd_timer_user *tu;
2077         void __user *argp = (void __user *)arg;
2078         int __user *p = argp;
2079 
2080         tu = file->private_data;
2081         switch (cmd) {
2082         case SNDRV_TIMER_IOCTL_PVERSION:
2083                 return put_user(SNDRV_TIMER_VERSION, p) ? -EFAULT : 0;
2084         case SNDRV_TIMER_IOCTL_NEXT_DEVICE:
2085                 return snd_timer_user_next_device(argp);
2086         case SNDRV_TIMER_IOCTL_TREAD_OLD:
2087         case SNDRV_TIMER_IOCTL_TREAD64:
2088                 return snd_timer_user_tread(argp, tu, cmd, compat);
2089         case SNDRV_TIMER_IOCTL_GINFO:
2090                 return snd_timer_user_ginfo(file, argp);
2091         case SNDRV_TIMER_IOCTL_GPARAMS:
2092                 return snd_timer_user_gparams(file, argp);
2093         case SNDRV_TIMER_IOCTL_GSTATUS:
2094                 return snd_timer_user_gstatus(file, argp);
2095         case SNDRV_TIMER_IOCTL_SELECT:
2096                 return snd_timer_user_tselect(file, argp);
2097         case SNDRV_TIMER_IOCTL_INFO:
2098                 return snd_timer_user_info(file, argp);
2099         case SNDRV_TIMER_IOCTL_PARAMS:
2100                 return snd_timer_user_params(file, argp);
2101         case SNDRV_TIMER_IOCTL_STATUS32:
2102                 return snd_timer_user_status32(file, argp);
2103         case SNDRV_TIMER_IOCTL_STATUS64:
2104                 return snd_timer_user_status64(file, argp);
2105         case SNDRV_TIMER_IOCTL_START:
2106         case SNDRV_TIMER_IOCTL_START_OLD:
2107                 return snd_timer_user_start(file);
2108         case SNDRV_TIMER_IOCTL_STOP:
2109         case SNDRV_TIMER_IOCTL_STOP_OLD:
2110                 return snd_timer_user_stop(file);
2111         case SNDRV_TIMER_IOCTL_CONTINUE:
2112         case SNDRV_TIMER_IOCTL_CONTINUE_OLD:
2113                 return snd_timer_user_continue(file);
2114         case SNDRV_TIMER_IOCTL_PAUSE:
2115         case SNDRV_TIMER_IOCTL_PAUSE_OLD:
2116                 return snd_timer_user_pause(file);
2117         }
2118         return -ENOTTY;
2119 }
2120 
2121 static long snd_timer_user_ioctl(struct file *file, unsigned int cmd,
2122                                  unsigned long arg)
2123 {
2124         struct snd_timer_user *tu = file->private_data;
2125         long ret;
2126 
2127         mutex_lock(&tu->ioctl_lock);
2128         ret = __snd_timer_user_ioctl(file, cmd, arg, false);
2129         mutex_unlock(&tu->ioctl_lock);
2130         return ret;
2131 }
2132 
2133 static int snd_timer_user_fasync(int fd, struct file * file, int on)
2134 {
2135         struct snd_timer_user *tu;
2136 
2137         tu = file->private_data;
2138         return fasync_helper(fd, file, on, &tu->fasync);
2139 }
2140 
2141 static ssize_t snd_timer_user_read(struct file *file, char __user *buffer,
2142                                    size_t count, loff_t *offset)
2143 {
2144         struct snd_timer_tread64 *tread;
2145         struct snd_timer_tread32 tread32;
2146         struct snd_timer_user *tu;
2147         long result = 0, unit;
2148         int qhead;
2149         int err = 0;
2150 
2151         tu = file->private_data;
2152         switch (tu->tread) {
2153         case TREAD_FORMAT_TIME64:
2154                 unit = sizeof(struct snd_timer_tread64);
2155                 break;
2156         case TREAD_FORMAT_TIME32:
2157                 unit = sizeof(struct snd_timer_tread32);
2158                 break;
2159         case TREAD_FORMAT_NONE:
2160                 unit = sizeof(struct snd_timer_read);
2161                 break;
2162         default:
2163                 WARN_ONCE(1, "Corrupt snd_timer_user\n");
2164                 return -ENOTSUPP;
2165         }
2166 
2167         mutex_lock(&tu->ioctl_lock);
2168         spin_lock_irq(&tu->qlock);
2169         while ((long)count - result >= unit) {
2170                 while (!tu->qused) {
2171                         wait_queue_entry_t wait;
2172 
2173                         if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
2174                                 err = -EAGAIN;
2175                                 goto _error;
2176                         }
2177 
2178                         set_current_state(TASK_INTERRUPTIBLE);
2179                         init_waitqueue_entry(&wait, current);
2180                         add_wait_queue(&tu->qchange_sleep, &wait);
2181 
2182                         spin_unlock_irq(&tu->qlock);
2183                         mutex_unlock(&tu->ioctl_lock);
2184                         schedule();
2185                         mutex_lock(&tu->ioctl_lock);
2186                         spin_lock_irq(&tu->qlock);
2187 
2188                         remove_wait_queue(&tu->qchange_sleep, &wait);
2189 
2190                         if (tu->disconnected) {
2191                                 err = -ENODEV;
2192                                 goto _error;
2193                         }
2194                         if (signal_pending(current)) {
2195                                 err = -ERESTARTSYS;
2196                                 goto _error;
2197                         }
2198                 }
2199 
2200                 qhead = tu->qhead++;
2201                 tu->qhead %= tu->queue_size;
2202                 tu->qused--;
2203                 spin_unlock_irq(&tu->qlock);
2204 
2205                 tread = &tu->tqueue[qhead];
2206 
2207                 switch (tu->tread) {
2208                 case TREAD_FORMAT_TIME64:
2209                         if (copy_to_user(buffer, tread,
2210                                          sizeof(struct snd_timer_tread64)))
2211                                 err = -EFAULT;
2212                         break;
2213                 case TREAD_FORMAT_TIME32:
2214                         memset(&tread32, 0, sizeof(tread32));
2215                         tread32 = (struct snd_timer_tread32) {
2216                                 .event = tread->event,
2217                                 .tstamp_sec = tread->tstamp_sec,
2218                                 .tstamp_nsec = tread->tstamp_nsec,
2219                                 .val = tread->val,
2220                         };
2221 
2222                         if (copy_to_user(buffer, &tread32, sizeof(tread32)))
2223                                 err = -EFAULT;
2224                         break;
2225                 case TREAD_FORMAT_NONE:
2226                         if (copy_to_user(buffer, &tu->queue[qhead],
2227                                          sizeof(struct snd_timer_read)))
2228                                 err = -EFAULT;
2229                         break;
2230                 default:
2231                         err = -ENOTSUPP;
2232                         break;
2233                 }
2234 
2235                 spin_lock_irq(&tu->qlock);
2236                 if (err < 0)
2237                         goto _error;
2238                 result += unit;
2239                 buffer += unit;
2240         }
2241  _error:
2242         spin_unlock_irq(&tu->qlock);
2243         mutex_unlock(&tu->ioctl_lock);
2244         return result > 0 ? result : err;
2245 }
2246 
2247 static __poll_t snd_timer_user_poll(struct file *file, poll_table * wait)
2248 {
2249         __poll_t mask;
2250         struct snd_timer_user *tu;
2251 
2252         tu = file->private_data;
2253 
2254         poll_wait(file, &tu->qchange_sleep, wait);
2255 
2256         mask = 0;
2257         spin_lock_irq(&tu->qlock);
2258         if (tu->qused)
2259                 mask |= EPOLLIN | EPOLLRDNORM;
2260         if (tu->disconnected)
2261                 mask |= EPOLLERR;
2262         spin_unlock_irq(&tu->qlock);
2263 
2264         return mask;
2265 }
2266 
2267 #ifdef CONFIG_COMPAT
2268 #include "timer_compat.c"
2269 #else
2270 #define snd_timer_user_ioctl_compat     NULL
2271 #endif
2272 
2273 static const struct file_operations snd_timer_f_ops =
2274 {
2275         .owner =        THIS_MODULE,
2276         .read =         snd_timer_user_read,
2277         .open =         snd_timer_user_open,
2278         .release =      snd_timer_user_release,
2279         .llseek =       no_llseek,
2280         .poll =         snd_timer_user_poll,
2281         .unlocked_ioctl =       snd_timer_user_ioctl,
2282         .compat_ioctl = snd_timer_user_ioctl_compat,
2283         .fasync =       snd_timer_user_fasync,
2284 };
2285 
2286 /* unregister the system timer */
2287 static void snd_timer_free_all(void)
2288 {
2289         struct snd_timer *timer, *n;
2290 
2291         list_for_each_entry_safe(timer, n, &snd_timer_list, device_list)
2292                 snd_timer_free(timer);
2293 }
2294 
2295 static struct device timer_dev;
2296 
2297 /*
2298  *  ENTRY functions
2299  */
2300 
2301 static int __init alsa_timer_init(void)
2302 {
2303         int err;
2304 
2305         snd_device_initialize(&timer_dev, NULL);
2306         dev_set_name(&timer_dev, "timer");
2307 
2308 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
2309         snd_oss_info_register(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1,
2310                               "system timer");
2311 #endif
2312 
2313         err = snd_timer_register_system();
2314         if (err < 0) {
2315                 pr_err("ALSA: unable to register system timer (%i)\n", err);
2316                 goto put_timer;
2317         }
2318 
2319         err = snd_register_device(SNDRV_DEVICE_TYPE_TIMER, NULL, 0,
2320                                   &snd_timer_f_ops, NULL, &timer_dev);
2321         if (err < 0) {
2322                 pr_err("ALSA: unable to register timer device (%i)\n", err);
2323                 snd_timer_free_all();
2324                 goto put_timer;
2325         }
2326 
2327         snd_timer_proc_init();
2328         return 0;
2329 
2330 put_timer:
2331         put_device(&timer_dev);
2332         return err;
2333 }
2334 
2335 static void __exit alsa_timer_exit(void)
2336 {
2337         snd_unregister_device(&timer_dev);
2338         snd_timer_free_all();
2339         put_device(&timer_dev);
2340         snd_timer_proc_done();
2341 #ifdef SNDRV_OSS_INFO_DEV_TIMERS
2342         snd_oss_info_unregister(SNDRV_OSS_INFO_DEV_TIMERS, SNDRV_CARDS - 1);
2343 #endif
2344 }
2345 
2346 module_init(alsa_timer_init)
2347 module_exit(alsa_timer_exit)
2348 

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