forked from gregkh/linux
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathtimer.c
2347 lines (2111 loc) · 58.3 KB
/
timer.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Timers abstract layer
* Copyright (c) by Jaroslav Kysela <[email protected]>
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/mutex.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/sched/signal.h>
#include <sound/core.h>
#include <sound/timer.h>
#include <sound/control.h>
#include <sound/info.h>
#include <sound/minors.h>
#include <sound/initval.h>
#include <linux/kmod.h>
/* internal flags */
#define SNDRV_TIMER_IFLG_PAUSED 0x00010000
#define SNDRV_TIMER_IFLG_DEAD 0x00020000
#if IS_ENABLED(CONFIG_SND_HRTIMER)
#define DEFAULT_TIMER_LIMIT 4
#else
#define DEFAULT_TIMER_LIMIT 1
#endif
static int timer_limit = DEFAULT_TIMER_LIMIT;
static int timer_tstamp_monotonic = 1;
MODULE_AUTHOR("Jaroslav Kysela <[email protected]>, Takashi Iwai <[email protected]>");
MODULE_DESCRIPTION("ALSA timer interface");
MODULE_LICENSE("GPL");
module_param(timer_limit, int, 0444);
MODULE_PARM_DESC(timer_limit, "Maximum global timers in system.");
module_param(timer_tstamp_monotonic, int, 0444);
MODULE_PARM_DESC(timer_tstamp_monotonic, "Use posix monotonic clock source for timestamps (default).");
MODULE_ALIAS_CHARDEV(CONFIG_SND_MAJOR, SNDRV_MINOR_TIMER);
MODULE_ALIAS("devname:snd/timer");
enum timer_tread_format {
TREAD_FORMAT_NONE = 0,
TREAD_FORMAT_TIME64,
TREAD_FORMAT_TIME32,
};
struct snd_timer_tread32 {
int event;
s32 tstamp_sec;
s32 tstamp_nsec;
unsigned int val;
};
struct snd_timer_tread64 {
int event;
u8 pad1[4];
s64 tstamp_sec;
s64 tstamp_nsec;
unsigned int val;
u8 pad2[4];
};
struct snd_timer_user {
struct snd_timer_instance *timeri;
int tread; /* enhanced read with timestamps and events */
unsigned long ticks;
unsigned long overrun;
int qhead;
int qtail;
int qused;
int queue_size;
bool disconnected;
struct snd_timer_read *queue;
struct snd_timer_tread64 *tqueue;
spinlock_t qlock;
unsigned long last_resolution;
unsigned int filter;
struct timespec64 tstamp; /* trigger tstamp */
wait_queue_head_t qchange_sleep;
struct fasync_struct *fasync;
struct mutex ioctl_lock;
};
struct snd_timer_status32 {
s32 tstamp_sec; /* Timestamp - last update */
s32 tstamp_nsec;
unsigned int resolution; /* current period resolution in ns */
unsigned int lost; /* counter of master tick lost */
unsigned int overrun; /* count of read queue overruns */
unsigned int queue; /* used queue size */
unsigned char reserved[64]; /* reserved */
};
#define SNDRV_TIMER_IOCTL_STATUS32 _IOR('T', 0x14, struct snd_timer_status32)
struct snd_timer_status64 {
s64 tstamp_sec; /* Timestamp - last update */
s64 tstamp_nsec;
unsigned int resolution; /* current period resolution in ns */
unsigned int lost; /* counter of master tick lost */
unsigned int overrun; /* count of read queue overruns */
unsigned int queue; /* used queue size */
unsigned char reserved[64]; /* reserved */
};
#define SNDRV_TIMER_IOCTL_STATUS64 _IOR('T', 0x14, struct snd_timer_status64)
/* list of timers */
static LIST_HEAD(snd_timer_list);
/* list of slave instances */
static LIST_HEAD(snd_timer_slave_list);
/* lock for slave active lists */
static DEFINE_SPINLOCK(slave_active_lock);
#define MAX_SLAVE_INSTANCES 1000
static int num_slaves;
static DEFINE_MUTEX(register_mutex);
static int snd_timer_free(struct snd_timer *timer);
static int snd_timer_dev_free(struct snd_device *device);
static int snd_timer_dev_register(struct snd_device *device);
static int snd_timer_dev_disconnect(struct snd_device *device);
static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left);
/*
* create a timer instance with the given owner string.
*/
struct snd_timer_instance *snd_timer_instance_new(const char *owner)
{
struct snd_timer_instance *timeri;
timeri = kzalloc(sizeof(*timeri), GFP_KERNEL);
if (timeri == NULL)
return NULL;
timeri->owner = kstrdup(owner, GFP_KERNEL);
if (! timeri->owner) {
kfree(timeri);
return NULL;
}
INIT_LIST_HEAD(&timeri->open_list);
INIT_LIST_HEAD(&timeri->active_list);
INIT_LIST_HEAD(&timeri->ack_list);
INIT_LIST_HEAD(&timeri->slave_list_head);
INIT_LIST_HEAD(&timeri->slave_active_head);
return timeri;
}
EXPORT_SYMBOL(snd_timer_instance_new);
void snd_timer_instance_free(struct snd_timer_instance *timeri)
{
if (timeri) {
if (timeri->private_free)
timeri->private_free(timeri);
kfree(timeri->owner);
kfree(timeri);
}
}
EXPORT_SYMBOL(snd_timer_instance_free);
/*
* find a timer instance from the given timer id
*/
static struct snd_timer *snd_timer_find(struct snd_timer_id *tid)
{
struct snd_timer *timer;
list_for_each_entry(timer, &snd_timer_list, device_list) {
if (timer->tmr_class != tid->dev_class)
continue;
if ((timer->tmr_class == SNDRV_TIMER_CLASS_CARD ||
timer->tmr_class == SNDRV_TIMER_CLASS_PCM) &&
(timer->card == NULL ||
timer->card->number != tid->card))
continue;
if (timer->tmr_device != tid->device)
continue;
if (timer->tmr_subdevice != tid->subdevice)
continue;
return timer;
}
return NULL;
}
#ifdef CONFIG_MODULES
static void snd_timer_request(struct snd_timer_id *tid)
{
switch (tid->dev_class) {
case SNDRV_TIMER_CLASS_GLOBAL:
if (tid->device < timer_limit)
request_module("snd-timer-%i", tid->device);
break;
case SNDRV_TIMER_CLASS_CARD:
case SNDRV_TIMER_CLASS_PCM:
if (tid->card < snd_ecards_limit)
request_module("snd-card-%i", tid->card);
break;
default:
break;
}
}
#endif
/* move the slave if it belongs to the master; return 1 if match */
static int check_matching_master_slave(struct snd_timer_instance *master,
struct snd_timer_instance *slave)
{
if (slave->slave_class != master->slave_class ||
slave->slave_id != master->slave_id)
return 0;
if (master->timer->num_instances >= master->timer->max_instances)
return -EBUSY;
list_move_tail(&slave->open_list, &master->slave_list_head);
master->timer->num_instances++;
spin_lock_irq(&slave_active_lock);
spin_lock(&master->timer->lock);
slave->master = master;
slave->timer = master->timer;
if (slave->flags & SNDRV_TIMER_IFLG_RUNNING)
list_add_tail(&slave->active_list, &master->slave_active_head);
spin_unlock(&master->timer->lock);
spin_unlock_irq(&slave_active_lock);
return 1;
}
/*
* look for a master instance matching with the slave id of the given slave.
* when found, relink the open_link of the slave.
*
* call this with register_mutex down.
*/
static int snd_timer_check_slave(struct snd_timer_instance *slave)
{
struct snd_timer *timer;
struct snd_timer_instance *master;
int err = 0;
/* FIXME: it's really dumb to look up all entries.. */
list_for_each_entry(timer, &snd_timer_list, device_list) {
list_for_each_entry(master, &timer->open_list_head, open_list) {
err = check_matching_master_slave(master, slave);
if (err != 0) /* match found or error */
goto out;
}
}
out:
return err < 0 ? err : 0;
}
/*
* look for slave instances matching with the slave id of the given master.
* when found, relink the open_link of slaves.
*
* call this with register_mutex down.
*/
static int snd_timer_check_master(struct snd_timer_instance *master)
{
struct snd_timer_instance *slave, *tmp;
int err = 0;
/* check all pending slaves */
list_for_each_entry_safe(slave, tmp, &snd_timer_slave_list, open_list) {
err = check_matching_master_slave(master, slave);
if (err < 0)
break;
}
return err < 0 ? err : 0;
}
static void snd_timer_close_locked(struct snd_timer_instance *timeri,
struct device **card_devp_to_put);
/*
* open a timer instance
* when opening a master, the slave id must be here given.
*/
int snd_timer_open(struct snd_timer_instance *timeri,
struct snd_timer_id *tid,
unsigned int slave_id)
{
struct snd_timer *timer;
struct device *card_dev_to_put = NULL;
int err;
mutex_lock(®ister_mutex);
if (tid->dev_class == SNDRV_TIMER_CLASS_SLAVE) {
/* open a slave instance */
if (tid->dev_sclass <= SNDRV_TIMER_SCLASS_NONE ||
tid->dev_sclass > SNDRV_TIMER_SCLASS_OSS_SEQUENCER) {
pr_debug("ALSA: timer: invalid slave class %i\n",
tid->dev_sclass);
err = -EINVAL;
goto unlock;
}
if (num_slaves >= MAX_SLAVE_INSTANCES) {
err = -EBUSY;
goto unlock;
}
timeri->slave_class = tid->dev_sclass;
timeri->slave_id = tid->device;
timeri->flags |= SNDRV_TIMER_IFLG_SLAVE;
list_add_tail(&timeri->open_list, &snd_timer_slave_list);
num_slaves++;
err = snd_timer_check_slave(timeri);
goto list_added;
}
/* open a master instance */
timer = snd_timer_find(tid);
#ifdef CONFIG_MODULES
if (!timer) {
mutex_unlock(®ister_mutex);
snd_timer_request(tid);
mutex_lock(®ister_mutex);
timer = snd_timer_find(tid);
}
#endif
if (!timer) {
err = -ENODEV;
goto unlock;
}
if (!list_empty(&timer->open_list_head)) {
struct snd_timer_instance *t =
list_entry(timer->open_list_head.next,
struct snd_timer_instance, open_list);
if (t->flags & SNDRV_TIMER_IFLG_EXCLUSIVE) {
err = -EBUSY;
goto unlock;
}
}
if (timer->num_instances >= timer->max_instances) {
err = -EBUSY;
goto unlock;
}
if (!try_module_get(timer->module)) {
err = -EBUSY;
goto unlock;
}
/* take a card refcount for safe disconnection */
if (timer->card) {
get_device(&timer->card->card_dev);
card_dev_to_put = &timer->card->card_dev;
}
if (list_empty(&timer->open_list_head) && timer->hw.open) {
err = timer->hw.open(timer);
if (err) {
module_put(timer->module);
goto unlock;
}
}
timeri->timer = timer;
timeri->slave_class = tid->dev_sclass;
timeri->slave_id = slave_id;
list_add_tail(&timeri->open_list, &timer->open_list_head);
timer->num_instances++;
err = snd_timer_check_master(timeri);
list_added:
if (err < 0)
snd_timer_close_locked(timeri, &card_dev_to_put);
unlock:
mutex_unlock(®ister_mutex);
/* put_device() is called after unlock for avoiding deadlock */
if (err < 0 && card_dev_to_put)
put_device(card_dev_to_put);
return err;
}
EXPORT_SYMBOL(snd_timer_open);
/*
* close a timer instance
* call this with register_mutex down.
*/
static void snd_timer_close_locked(struct snd_timer_instance *timeri,
struct device **card_devp_to_put)
{
struct snd_timer *timer = timeri->timer;
struct snd_timer_instance *slave, *tmp;
if (timer) {
spin_lock_irq(&timer->lock);
timeri->flags |= SNDRV_TIMER_IFLG_DEAD;
spin_unlock_irq(&timer->lock);
}
if (!list_empty(&timeri->open_list)) {
list_del_init(&timeri->open_list);
if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
num_slaves--;
}
/* force to stop the timer */
snd_timer_stop(timeri);
if (timer) {
timer->num_instances--;
/* wait, until the active callback is finished */
spin_lock_irq(&timer->lock);
while (timeri->flags & SNDRV_TIMER_IFLG_CALLBACK) {
spin_unlock_irq(&timer->lock);
udelay(10);
spin_lock_irq(&timer->lock);
}
spin_unlock_irq(&timer->lock);
/* remove slave links */
spin_lock_irq(&slave_active_lock);
spin_lock(&timer->lock);
timeri->timer = NULL;
list_for_each_entry_safe(slave, tmp, &timeri->slave_list_head,
open_list) {
list_move_tail(&slave->open_list, &snd_timer_slave_list);
timer->num_instances--;
slave->master = NULL;
slave->timer = NULL;
list_del_init(&slave->ack_list);
list_del_init(&slave->active_list);
}
spin_unlock(&timer->lock);
spin_unlock_irq(&slave_active_lock);
/* slave doesn't need to release timer resources below */
if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
timer = NULL;
}
if (timer) {
if (list_empty(&timer->open_list_head) && timer->hw.close)
timer->hw.close(timer);
/* release a card refcount for safe disconnection */
if (timer->card)
*card_devp_to_put = &timer->card->card_dev;
module_put(timer->module);
}
}
/*
* close a timer instance
*/
void snd_timer_close(struct snd_timer_instance *timeri)
{
struct device *card_dev_to_put = NULL;
if (snd_BUG_ON(!timeri))
return;
mutex_lock(®ister_mutex);
snd_timer_close_locked(timeri, &card_dev_to_put);
mutex_unlock(®ister_mutex);
/* put_device() is called after unlock for avoiding deadlock */
if (card_dev_to_put)
put_device(card_dev_to_put);
}
EXPORT_SYMBOL(snd_timer_close);
static unsigned long snd_timer_hw_resolution(struct snd_timer *timer)
{
if (timer->hw.c_resolution)
return timer->hw.c_resolution(timer);
else
return timer->hw.resolution;
}
unsigned long snd_timer_resolution(struct snd_timer_instance *timeri)
{
struct snd_timer * timer;
unsigned long ret = 0;
unsigned long flags;
if (timeri == NULL)
return 0;
timer = timeri->timer;
if (timer) {
spin_lock_irqsave(&timer->lock, flags);
ret = snd_timer_hw_resolution(timer);
spin_unlock_irqrestore(&timer->lock, flags);
}
return ret;
}
EXPORT_SYMBOL(snd_timer_resolution);
static void snd_timer_notify1(struct snd_timer_instance *ti, int event)
{
struct snd_timer *timer = ti->timer;
unsigned long resolution = 0;
struct snd_timer_instance *ts;
struct timespec64 tstamp;
if (timer_tstamp_monotonic)
ktime_get_ts64(&tstamp);
else
ktime_get_real_ts64(&tstamp);
if (snd_BUG_ON(event < SNDRV_TIMER_EVENT_START ||
event > SNDRV_TIMER_EVENT_PAUSE))
return;
if (timer &&
(event == SNDRV_TIMER_EVENT_START ||
event == SNDRV_TIMER_EVENT_CONTINUE))
resolution = snd_timer_hw_resolution(timer);
if (ti->ccallback)
ti->ccallback(ti, event, &tstamp, resolution);
if (ti->flags & SNDRV_TIMER_IFLG_SLAVE)
return;
if (timer == NULL)
return;
if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
return;
list_for_each_entry(ts, &ti->slave_active_head, active_list)
if (ts->ccallback)
ts->ccallback(ts, event + 100, &tstamp, resolution);
}
/* start/continue a master timer */
static int snd_timer_start1(struct snd_timer_instance *timeri,
bool start, unsigned long ticks)
{
struct snd_timer *timer;
int result;
unsigned long flags;
timer = timeri->timer;
if (!timer)
return -EINVAL;
spin_lock_irqsave(&timer->lock, flags);
if (timeri->flags & SNDRV_TIMER_IFLG_DEAD) {
result = -EINVAL;
goto unlock;
}
if (timer->card && timer->card->shutdown) {
result = -ENODEV;
goto unlock;
}
if (timeri->flags & (SNDRV_TIMER_IFLG_RUNNING |
SNDRV_TIMER_IFLG_START)) {
result = -EBUSY;
goto unlock;
}
if (start)
timeri->ticks = timeri->cticks = ticks;
else if (!timeri->cticks)
timeri->cticks = 1;
timeri->pticks = 0;
list_move_tail(&timeri->active_list, &timer->active_list_head);
if (timer->running) {
if (timer->hw.flags & SNDRV_TIMER_HW_SLAVE)
goto __start_now;
timer->flags |= SNDRV_TIMER_FLG_RESCHED;
timeri->flags |= SNDRV_TIMER_IFLG_START;
result = 1; /* delayed start */
} else {
if (start)
timer->sticks = ticks;
timer->hw.start(timer);
__start_now:
timer->running++;
timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
result = 0;
}
snd_timer_notify1(timeri, start ? SNDRV_TIMER_EVENT_START :
SNDRV_TIMER_EVENT_CONTINUE);
unlock:
spin_unlock_irqrestore(&timer->lock, flags);
return result;
}
/* start/continue a slave timer */
static int snd_timer_start_slave(struct snd_timer_instance *timeri,
bool start)
{
unsigned long flags;
int err;
spin_lock_irqsave(&slave_active_lock, flags);
if (timeri->flags & SNDRV_TIMER_IFLG_DEAD) {
err = -EINVAL;
goto unlock;
}
if (timeri->flags & SNDRV_TIMER_IFLG_RUNNING) {
err = -EBUSY;
goto unlock;
}
timeri->flags |= SNDRV_TIMER_IFLG_RUNNING;
if (timeri->master && timeri->timer) {
spin_lock(&timeri->timer->lock);
list_add_tail(&timeri->active_list,
&timeri->master->slave_active_head);
snd_timer_notify1(timeri, start ? SNDRV_TIMER_EVENT_START :
SNDRV_TIMER_EVENT_CONTINUE);
spin_unlock(&timeri->timer->lock);
}
err = 1; /* delayed start */
unlock:
spin_unlock_irqrestore(&slave_active_lock, flags);
return err;
}
/* stop/pause a master timer */
static int snd_timer_stop1(struct snd_timer_instance *timeri, bool stop)
{
struct snd_timer *timer;
int result = 0;
unsigned long flags;
timer = timeri->timer;
if (!timer)
return -EINVAL;
spin_lock_irqsave(&timer->lock, flags);
if (!(timeri->flags & (SNDRV_TIMER_IFLG_RUNNING |
SNDRV_TIMER_IFLG_START))) {
result = -EBUSY;
goto unlock;
}
list_del_init(&timeri->ack_list);
list_del_init(&timeri->active_list);
if (timer->card && timer->card->shutdown)
goto unlock;
if (stop) {
timeri->cticks = timeri->ticks;
timeri->pticks = 0;
}
if ((timeri->flags & SNDRV_TIMER_IFLG_RUNNING) &&
!(--timer->running)) {
timer->hw.stop(timer);
if (timer->flags & SNDRV_TIMER_FLG_RESCHED) {
timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
snd_timer_reschedule(timer, 0);
if (timer->flags & SNDRV_TIMER_FLG_CHANGE) {
timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
timer->hw.start(timer);
}
}
}
timeri->flags &= ~(SNDRV_TIMER_IFLG_RUNNING | SNDRV_TIMER_IFLG_START);
if (stop)
timeri->flags &= ~SNDRV_TIMER_IFLG_PAUSED;
else
timeri->flags |= SNDRV_TIMER_IFLG_PAUSED;
snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :
SNDRV_TIMER_EVENT_PAUSE);
unlock:
spin_unlock_irqrestore(&timer->lock, flags);
return result;
}
/* stop/pause a slave timer */
static int snd_timer_stop_slave(struct snd_timer_instance *timeri, bool stop)
{
unsigned long flags;
spin_lock_irqsave(&slave_active_lock, flags);
if (!(timeri->flags & SNDRV_TIMER_IFLG_RUNNING)) {
spin_unlock_irqrestore(&slave_active_lock, flags);
return -EBUSY;
}
timeri->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
if (timeri->timer) {
spin_lock(&timeri->timer->lock);
list_del_init(&timeri->ack_list);
list_del_init(&timeri->active_list);
snd_timer_notify1(timeri, stop ? SNDRV_TIMER_EVENT_STOP :
SNDRV_TIMER_EVENT_PAUSE);
spin_unlock(&timeri->timer->lock);
}
spin_unlock_irqrestore(&slave_active_lock, flags);
return 0;
}
/*
* start the timer instance
*/
int snd_timer_start(struct snd_timer_instance *timeri, unsigned int ticks)
{
if (timeri == NULL || ticks < 1)
return -EINVAL;
if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
return snd_timer_start_slave(timeri, true);
else
return snd_timer_start1(timeri, true, ticks);
}
EXPORT_SYMBOL(snd_timer_start);
/*
* stop the timer instance.
*
* do not call this from the timer callback!
*/
int snd_timer_stop(struct snd_timer_instance *timeri)
{
if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
return snd_timer_stop_slave(timeri, true);
else
return snd_timer_stop1(timeri, true);
}
EXPORT_SYMBOL(snd_timer_stop);
/*
* start again.. the tick is kept.
*/
int snd_timer_continue(struct snd_timer_instance *timeri)
{
/* timer can continue only after pause */
if (!(timeri->flags & SNDRV_TIMER_IFLG_PAUSED))
return -EINVAL;
if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
return snd_timer_start_slave(timeri, false);
else
return snd_timer_start1(timeri, false, 0);
}
EXPORT_SYMBOL(snd_timer_continue);
/*
* pause.. remember the ticks left
*/
int snd_timer_pause(struct snd_timer_instance * timeri)
{
if (timeri->flags & SNDRV_TIMER_IFLG_SLAVE)
return snd_timer_stop_slave(timeri, false);
else
return snd_timer_stop1(timeri, false);
}
EXPORT_SYMBOL(snd_timer_pause);
/*
* reschedule the timer
*
* start pending instances and check the scheduling ticks.
* when the scheduling ticks is changed set CHANGE flag to reprogram the timer.
*/
static void snd_timer_reschedule(struct snd_timer * timer, unsigned long ticks_left)
{
struct snd_timer_instance *ti;
unsigned long ticks = ~0UL;
list_for_each_entry(ti, &timer->active_list_head, active_list) {
if (ti->flags & SNDRV_TIMER_IFLG_START) {
ti->flags &= ~SNDRV_TIMER_IFLG_START;
ti->flags |= SNDRV_TIMER_IFLG_RUNNING;
timer->running++;
}
if (ti->flags & SNDRV_TIMER_IFLG_RUNNING) {
if (ticks > ti->cticks)
ticks = ti->cticks;
}
}
if (ticks == ~0UL) {
timer->flags &= ~SNDRV_TIMER_FLG_RESCHED;
return;
}
if (ticks > timer->hw.ticks)
ticks = timer->hw.ticks;
if (ticks_left != ticks)
timer->flags |= SNDRV_TIMER_FLG_CHANGE;
timer->sticks = ticks;
}
/* call callbacks in timer ack list */
static void snd_timer_process_callbacks(struct snd_timer *timer,
struct list_head *head)
{
struct snd_timer_instance *ti;
unsigned long resolution, ticks;
while (!list_empty(head)) {
ti = list_first_entry(head, struct snd_timer_instance,
ack_list);
/* remove from ack_list and make empty */
list_del_init(&ti->ack_list);
if (!(ti->flags & SNDRV_TIMER_IFLG_DEAD)) {
ticks = ti->pticks;
ti->pticks = 0;
resolution = ti->resolution;
ti->flags |= SNDRV_TIMER_IFLG_CALLBACK;
spin_unlock(&timer->lock);
if (ti->callback)
ti->callback(ti, resolution, ticks);
spin_lock(&timer->lock);
ti->flags &= ~SNDRV_TIMER_IFLG_CALLBACK;
}
}
}
/* clear pending instances from ack list */
static void snd_timer_clear_callbacks(struct snd_timer *timer,
struct list_head *head)
{
unsigned long flags;
spin_lock_irqsave(&timer->lock, flags);
while (!list_empty(head))
list_del_init(head->next);
spin_unlock_irqrestore(&timer->lock, flags);
}
/*
* timer work
*
*/
static void snd_timer_work(struct work_struct *work)
{
struct snd_timer *timer = container_of(work, struct snd_timer, task_work);
unsigned long flags;
if (timer->card && timer->card->shutdown) {
snd_timer_clear_callbacks(timer, &timer->sack_list_head);
return;
}
spin_lock_irqsave(&timer->lock, flags);
snd_timer_process_callbacks(timer, &timer->sack_list_head);
spin_unlock_irqrestore(&timer->lock, flags);
}
/*
* timer interrupt
*
* ticks_left is usually equal to timer->sticks.
*
*/
void snd_timer_interrupt(struct snd_timer * timer, unsigned long ticks_left)
{
struct snd_timer_instance *ti, *ts, *tmp;
unsigned long resolution;
struct list_head *ack_list_head;
unsigned long flags;
bool use_work = false;
if (timer == NULL)
return;
if (timer->card && timer->card->shutdown) {
snd_timer_clear_callbacks(timer, &timer->ack_list_head);
return;
}
spin_lock_irqsave(&timer->lock, flags);
/* remember the current resolution */
resolution = snd_timer_hw_resolution(timer);
/* loop for all active instances
* Here we cannot use list_for_each_entry because the active_list of a
* processed instance is relinked to done_list_head before the callback
* is called.
*/
list_for_each_entry_safe(ti, tmp, &timer->active_list_head,
active_list) {
if (ti->flags & SNDRV_TIMER_IFLG_DEAD)
continue;
if (!(ti->flags & SNDRV_TIMER_IFLG_RUNNING))
continue;
ti->pticks += ticks_left;
ti->resolution = resolution;
if (ti->cticks < ticks_left)
ti->cticks = 0;
else
ti->cticks -= ticks_left;
if (ti->cticks) /* not expired */
continue;
if (ti->flags & SNDRV_TIMER_IFLG_AUTO) {
ti->cticks = ti->ticks;
} else {
ti->flags &= ~SNDRV_TIMER_IFLG_RUNNING;
--timer->running;
list_del_init(&ti->active_list);
}
if ((timer->hw.flags & SNDRV_TIMER_HW_WORK) ||
(ti->flags & SNDRV_TIMER_IFLG_FAST))
ack_list_head = &timer->ack_list_head;
else
ack_list_head = &timer->sack_list_head;
if (list_empty(&ti->ack_list))
list_add_tail(&ti->ack_list, ack_list_head);
list_for_each_entry(ts, &ti->slave_active_head, active_list) {
ts->pticks = ti->pticks;
ts->resolution = resolution;
if (list_empty(&ts->ack_list))
list_add_tail(&ts->ack_list, ack_list_head);
}
}
if (timer->flags & SNDRV_TIMER_FLG_RESCHED)
snd_timer_reschedule(timer, timer->sticks);
if (timer->running) {
if (timer->hw.flags & SNDRV_TIMER_HW_STOP) {
timer->hw.stop(timer);
timer->flags |= SNDRV_TIMER_FLG_CHANGE;
}
if (!(timer->hw.flags & SNDRV_TIMER_HW_AUTO) ||
(timer->flags & SNDRV_TIMER_FLG_CHANGE)) {
/* restart timer */
timer->flags &= ~SNDRV_TIMER_FLG_CHANGE;
timer->hw.start(timer);
}
} else {
timer->hw.stop(timer);
}
/* now process all fast callbacks */
snd_timer_process_callbacks(timer, &timer->ack_list_head);
/* do we have any slow callbacks? */
use_work = !list_empty(&timer->sack_list_head);
spin_unlock_irqrestore(&timer->lock, flags);
if (use_work)
queue_work(system_highpri_wq, &timer->task_work);
}
EXPORT_SYMBOL(snd_timer_interrupt);
/*
*/
int snd_timer_new(struct snd_card *card, char *id, struct snd_timer_id *tid,
struct snd_timer **rtimer)
{
struct snd_timer *timer;
int err;
static const struct snd_device_ops ops = {
.dev_free = snd_timer_dev_free,
.dev_register = snd_timer_dev_register,
.dev_disconnect = snd_timer_dev_disconnect,
};
if (snd_BUG_ON(!tid))
return -EINVAL;
if (tid->dev_class == SNDRV_TIMER_CLASS_CARD ||
tid->dev_class == SNDRV_TIMER_CLASS_PCM) {
if (WARN_ON(!card))
return -EINVAL;
}
if (rtimer)
*rtimer = NULL;
timer = kzalloc(sizeof(*timer), GFP_KERNEL);
if (!timer)
return -ENOMEM;
timer->tmr_class = tid->dev_class;
timer->card = card;
timer->tmr_device = tid->device;
timer->tmr_subdevice = tid->subdevice;
if (id)
strscpy(timer->id, id, sizeof(timer->id));
timer->sticks = 1;
INIT_LIST_HEAD(&timer->device_list);
INIT_LIST_HEAD(&timer->open_list_head);
INIT_LIST_HEAD(&timer->active_list_head);
INIT_LIST_HEAD(&timer->ack_list_head);
INIT_LIST_HEAD(&timer->sack_list_head);
spin_lock_init(&timer->lock);
INIT_WORK(&timer->task_work, snd_timer_work);
timer->max_instances = 1000; /* default limit per timer */
if (card != NULL) {
timer->module = card->module;
err = snd_device_new(card, SNDRV_DEV_TIMER, timer, &ops);
if (err < 0) {
snd_timer_free(timer);
return err;
}
}
if (rtimer)
*rtimer = timer;
return 0;
}
EXPORT_SYMBOL(snd_timer_new);
static int snd_timer_free(struct snd_timer *timer)
{
if (!timer)
return 0;
mutex_lock(®ister_mutex);
if (! list_empty(&timer->open_list_head)) {
struct list_head *p, *n;
struct snd_timer_instance *ti;
pr_warn("ALSA: timer %p is busy?\n", timer);
list_for_each_safe(p, n, &timer->open_list_head) {
list_del_init(p);
ti = list_entry(p, struct snd_timer_instance, open_list);
ti->timer = NULL;
}