1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18#include <linux/time.h>
19#include <linux/hrtimer.h>
20#include <linux/timerqueue.h>
21#include <linux/rtc.h>
22#include <linux/alarmtimer.h>
23#include <linux/mutex.h>
24#include <linux/platform_device.h>
25#include <linux/posix-timers.h>
26#include <linux/workqueue.h>
27#include <linux/freezer.h>
28
29
30
31
32
33
34
35
36
37static struct alarm_base {
38 spinlock_t lock;
39 struct timerqueue_head timerqueue;
40 ktime_t (*gettime)(void);
41 clockid_t base_clockid;
42} alarm_bases[ALARM_NUMTYPE];
43
44
45static ktime_t freezer_delta;
46static DEFINE_SPINLOCK(freezer_delta_lock);
47
48static struct wakeup_source *ws;
49
50#ifdef CONFIG_RTC_CLASS
51
52static struct rtc_timer rtctimer;
53static struct rtc_device *rtcdev;
54static DEFINE_SPINLOCK(rtcdev_lock);
55
56
57
58
59
60
61
62
63struct rtc_device *alarmtimer_get_rtcdev(void)
64{
65 unsigned long flags;
66 struct rtc_device *ret;
67
68 spin_lock_irqsave(&rtcdev_lock, flags);
69 ret = rtcdev;
70 spin_unlock_irqrestore(&rtcdev_lock, flags);
71
72 return ret;
73}
74
75
76static int alarmtimer_rtc_add_device(struct device *dev,
77 struct class_interface *class_intf)
78{
79 unsigned long flags;
80 struct rtc_device *rtc = to_rtc_device(dev);
81
82 if (rtcdev)
83 return -EBUSY;
84
85 if (!rtc->ops->set_alarm)
86 return -1;
87 if (!device_may_wakeup(rtc->dev.parent))
88 return -1;
89
90 spin_lock_irqsave(&rtcdev_lock, flags);
91 if (!rtcdev) {
92 rtcdev = rtc;
93
94 get_device(dev);
95 }
96 spin_unlock_irqrestore(&rtcdev_lock, flags);
97 return 0;
98}
99
100static inline void alarmtimer_rtc_timer_init(void)
101{
102 rtc_timer_init(&rtctimer, NULL, NULL);
103}
104
105static struct class_interface alarmtimer_rtc_interface = {
106 .add_dev = &alarmtimer_rtc_add_device,
107};
108
109static int alarmtimer_rtc_interface_setup(void)
110{
111 alarmtimer_rtc_interface.class = rtc_class;
112 return class_interface_register(&alarmtimer_rtc_interface);
113}
114static void alarmtimer_rtc_interface_remove(void)
115{
116 class_interface_unregister(&alarmtimer_rtc_interface);
117}
118#else
119struct rtc_device *alarmtimer_get_rtcdev(void)
120{
121 return NULL;
122}
123#define rtcdev (NULL)
124static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
125static inline void alarmtimer_rtc_interface_remove(void) { }
126static inline void alarmtimer_rtc_timer_init(void) { }
127#endif
128
129
130
131
132
133
134
135
136
137
138static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
139{
140 if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
141 timerqueue_del(&base->timerqueue, &alarm->node);
142
143 timerqueue_add(&base->timerqueue, &alarm->node);
144 alarm->state |= ALARMTIMER_STATE_ENQUEUED;
145}
146
147
148
149
150
151
152
153
154
155
156static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
157{
158 if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
159 return;
160
161 timerqueue_del(&base->timerqueue, &alarm->node);
162 alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
163}
164
165
166
167
168
169
170
171
172
173
174
175static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
176{
177 struct alarm *alarm = container_of(timer, struct alarm, timer);
178 struct alarm_base *base = &alarm_bases[alarm->type];
179 unsigned long flags;
180 int ret = HRTIMER_NORESTART;
181 int restart = ALARMTIMER_NORESTART;
182
183 spin_lock_irqsave(&base->lock, flags);
184 alarmtimer_dequeue(base, alarm);
185 spin_unlock_irqrestore(&base->lock, flags);
186
187 if (alarm->function)
188 restart = alarm->function(alarm, base->gettime());
189
190 spin_lock_irqsave(&base->lock, flags);
191 if (restart != ALARMTIMER_NORESTART) {
192 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
193 alarmtimer_enqueue(base, alarm);
194 ret = HRTIMER_RESTART;
195 }
196 spin_unlock_irqrestore(&base->lock, flags);
197
198 return ret;
199
200}
201
202ktime_t alarm_expires_remaining(const struct alarm *alarm)
203{
204 struct alarm_base *base = &alarm_bases[alarm->type];
205 return ktime_sub(alarm->node.expires, base->gettime());
206}
207EXPORT_SYMBOL_GPL(alarm_expires_remaining);
208
209#ifdef CONFIG_RTC_CLASS
210
211
212
213
214
215
216
217
218
219
220static int alarmtimer_suspend(struct device *dev)
221{
222 struct rtc_time tm;
223 ktime_t min, now;
224 unsigned long flags;
225 struct rtc_device *rtc;
226 int i;
227 int ret;
228
229 spin_lock_irqsave(&freezer_delta_lock, flags);
230 min = freezer_delta;
231 freezer_delta = ktime_set(0, 0);
232 spin_unlock_irqrestore(&freezer_delta_lock, flags);
233
234 rtc = alarmtimer_get_rtcdev();
235
236 if (!rtc)
237 return 0;
238
239
240 for (i = 0; i < ALARM_NUMTYPE; i++) {
241 struct alarm_base *base = &alarm_bases[i];
242 struct timerqueue_node *next;
243 ktime_t delta;
244
245 spin_lock_irqsave(&base->lock, flags);
246 next = timerqueue_getnext(&base->timerqueue);
247 spin_unlock_irqrestore(&base->lock, flags);
248 if (!next)
249 continue;
250 delta = ktime_sub(next->expires, base->gettime());
251 if (!min.tv64 || (delta.tv64 < min.tv64))
252 min = delta;
253 }
254 if (min.tv64 == 0)
255 return 0;
256
257 if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
258 __pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
259 return -EBUSY;
260 }
261
262
263 rtc_timer_cancel(rtc, &rtctimer);
264 rtc_read_time(rtc, &tm);
265 now = rtc_tm_to_ktime(tm);
266 now = ktime_add(now, min);
267
268
269 ret = rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
270 if (ret < 0)
271 __pm_wakeup_event(ws, MSEC_PER_SEC);
272 return ret;
273}
274#else
275static int alarmtimer_suspend(struct device *dev)
276{
277 return 0;
278}
279#endif
280
281static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
282{
283 ktime_t delta;
284 unsigned long flags;
285 struct alarm_base *base = &alarm_bases[type];
286
287 delta = ktime_sub(absexp, base->gettime());
288
289 spin_lock_irqsave(&freezer_delta_lock, flags);
290 if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
291 freezer_delta = delta;
292 spin_unlock_irqrestore(&freezer_delta_lock, flags);
293}
294
295
296
297
298
299
300
301
302void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
303 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
304{
305 timerqueue_init(&alarm->node);
306 hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
307 HRTIMER_MODE_ABS);
308 alarm->timer.function = alarmtimer_fired;
309 alarm->function = function;
310 alarm->type = type;
311 alarm->state = ALARMTIMER_STATE_INACTIVE;
312}
313EXPORT_SYMBOL_GPL(alarm_init);
314
315
316
317
318
319
320int alarm_start(struct alarm *alarm, ktime_t start)
321{
322 struct alarm_base *base = &alarm_bases[alarm->type];
323 unsigned long flags;
324 int ret;
325
326 spin_lock_irqsave(&base->lock, flags);
327 alarm->node.expires = start;
328 alarmtimer_enqueue(base, alarm);
329 ret = hrtimer_start(&alarm->timer, alarm->node.expires,
330 HRTIMER_MODE_ABS);
331 spin_unlock_irqrestore(&base->lock, flags);
332 return ret;
333}
334EXPORT_SYMBOL_GPL(alarm_start);
335
336
337
338
339
340
341int alarm_start_relative(struct alarm *alarm, ktime_t start)
342{
343 struct alarm_base *base = &alarm_bases[alarm->type];
344
345 start = ktime_add(start, base->gettime());
346 return alarm_start(alarm, start);
347}
348EXPORT_SYMBOL_GPL(alarm_start_relative);
349
350void alarm_restart(struct alarm *alarm)
351{
352 struct alarm_base *base = &alarm_bases[alarm->type];
353 unsigned long flags;
354
355 spin_lock_irqsave(&base->lock, flags);
356 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
357 hrtimer_restart(&alarm->timer);
358 alarmtimer_enqueue(base, alarm);
359 spin_unlock_irqrestore(&base->lock, flags);
360}
361EXPORT_SYMBOL_GPL(alarm_restart);
362
363
364
365
366
367
368
369
370int alarm_try_to_cancel(struct alarm *alarm)
371{
372 struct alarm_base *base = &alarm_bases[alarm->type];
373 unsigned long flags;
374 int ret;
375
376 spin_lock_irqsave(&base->lock, flags);
377 ret = hrtimer_try_to_cancel(&alarm->timer);
378 if (ret >= 0)
379 alarmtimer_dequeue(base, alarm);
380 spin_unlock_irqrestore(&base->lock, flags);
381 return ret;
382}
383EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
384
385
386
387
388
389
390
391
392int alarm_cancel(struct alarm *alarm)
393{
394 for (;;) {
395 int ret = alarm_try_to_cancel(alarm);
396 if (ret >= 0)
397 return ret;
398 cpu_relax();
399 }
400}
401EXPORT_SYMBOL_GPL(alarm_cancel);
402
403
404u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
405{
406 u64 overrun = 1;
407 ktime_t delta;
408
409 delta = ktime_sub(now, alarm->node.expires);
410
411 if (delta.tv64 < 0)
412 return 0;
413
414 if (unlikely(delta.tv64 >= interval.tv64)) {
415 s64 incr = ktime_to_ns(interval);
416
417 overrun = ktime_divns(delta, incr);
418
419 alarm->node.expires = ktime_add_ns(alarm->node.expires,
420 incr*overrun);
421
422 if (alarm->node.expires.tv64 > now.tv64)
423 return overrun;
424
425
426
427
428 overrun++;
429 }
430
431 alarm->node.expires = ktime_add(alarm->node.expires, interval);
432 return overrun;
433}
434EXPORT_SYMBOL_GPL(alarm_forward);
435
436u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
437{
438 struct alarm_base *base = &alarm_bases[alarm->type];
439
440 return alarm_forward(alarm, base->gettime(), interval);
441}
442EXPORT_SYMBOL_GPL(alarm_forward_now);
443
444
445
446
447
448
449static enum alarmtimer_type clock2alarm(clockid_t clockid)
450{
451 if (clockid == CLOCK_REALTIME_ALARM)
452 return ALARM_REALTIME;
453 if (clockid == CLOCK_BOOTTIME_ALARM)
454 return ALARM_BOOTTIME;
455 return -1;
456}
457
458
459
460
461
462
463
464static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
465 ktime_t now)
466{
467 struct k_itimer *ptr = container_of(alarm, struct k_itimer,
468 it.alarm.alarmtimer);
469 if (posix_timer_event(ptr, 0) != 0)
470 ptr->it_overrun++;
471
472
473 if (ptr->it.alarm.interval.tv64) {
474 ptr->it_overrun += alarm_forward(alarm, now,
475 ptr->it.alarm.interval);
476 return ALARMTIMER_RESTART;
477 }
478 return ALARMTIMER_NORESTART;
479}
480
481
482
483
484
485
486
487
488static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
489{
490 clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
491
492 if (!alarmtimer_get_rtcdev())
493 return -ENOTSUPP;
494
495 return hrtimer_get_res(baseid, tp);
496}
497
498
499
500
501
502
503
504
505static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
506{
507 struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
508
509 if (!alarmtimer_get_rtcdev())
510 return -ENOTSUPP;
511
512 *tp = ktime_to_timespec(base->gettime());
513 return 0;
514}
515
516
517
518
519
520
521
522static int alarm_timer_create(struct k_itimer *new_timer)
523{
524 enum alarmtimer_type type;
525 struct alarm_base *base;
526
527 if (!alarmtimer_get_rtcdev())
528 return -ENOTSUPP;
529
530 if (!capable(CAP_WAKE_ALARM))
531 return -EPERM;
532
533 type = clock2alarm(new_timer->it_clock);
534 base = &alarm_bases[type];
535 alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
536 return 0;
537}
538
539
540
541
542
543
544
545
546static void alarm_timer_get(struct k_itimer *timr,
547 struct itimerspec *cur_setting)
548{
549 memset(cur_setting, 0, sizeof(struct itimerspec));
550
551 cur_setting->it_interval =
552 ktime_to_timespec(timr->it.alarm.interval);
553 cur_setting->it_value =
554 ktime_to_timespec(timr->it.alarm.alarmtimer.node.expires);
555 return;
556}
557
558
559
560
561
562
563
564static int alarm_timer_del(struct k_itimer *timr)
565{
566 if (!rtcdev)
567 return -ENOTSUPP;
568
569 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
570 return TIMER_RETRY;
571
572 return 0;
573}
574
575
576
577
578
579
580
581
582
583
584static int alarm_timer_set(struct k_itimer *timr, int flags,
585 struct itimerspec *new_setting,
586 struct itimerspec *old_setting)
587{
588 if (!rtcdev)
589 return -ENOTSUPP;
590
591 if (old_setting)
592 alarm_timer_get(timr, old_setting);
593
594
595 if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
596 return TIMER_RETRY;
597
598
599 timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
600 alarm_start(&timr->it.alarm.alarmtimer,
601 timespec_to_ktime(new_setting->it_value));
602 return 0;
603}
604
605
606
607
608
609
610
611static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
612 ktime_t now)
613{
614 struct task_struct *task = (struct task_struct *)alarm->data;
615
616 alarm->data = NULL;
617 if (task)
618 wake_up_process(task);
619 return ALARMTIMER_NORESTART;
620}
621
622
623
624
625
626
627
628
629static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
630{
631 alarm->data = (void *)current;
632 do {
633 set_current_state(TASK_INTERRUPTIBLE);
634 alarm_start(alarm, absexp);
635 if (likely(alarm->data))
636 schedule();
637
638 alarm_cancel(alarm);
639 } while (alarm->data && !signal_pending(current));
640
641 __set_current_state(TASK_RUNNING);
642
643 return (alarm->data == NULL);
644}
645
646
647
648
649
650
651
652
653
654
655
656static int update_rmtp(ktime_t exp, enum alarmtimer_type type,
657 struct timespec __user *rmtp)
658{
659 struct timespec rmt;
660 ktime_t rem;
661
662 rem = ktime_sub(exp, alarm_bases[type].gettime());
663
664 if (rem.tv64 <= 0)
665 return 0;
666 rmt = ktime_to_timespec(rem);
667
668 if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
669 return -EFAULT;
670
671 return 1;
672
673}
674
675
676
677
678
679
680
681static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
682{
683 enum alarmtimer_type type = restart->nanosleep.clockid;
684 ktime_t exp;
685 struct timespec __user *rmtp;
686 struct alarm alarm;
687 int ret = 0;
688
689 exp.tv64 = restart->nanosleep.expires;
690 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
691
692 if (alarmtimer_do_nsleep(&alarm, exp))
693 goto out;
694
695 if (freezing(current))
696 alarmtimer_freezerset(exp, type);
697
698 rmtp = restart->nanosleep.rmtp;
699 if (rmtp) {
700 ret = update_rmtp(exp, type, rmtp);
701 if (ret <= 0)
702 goto out;
703 }
704
705
706
707 ret = -ERESTART_RESTARTBLOCK;
708out:
709 return ret;
710}
711
712
713
714
715
716
717
718
719
720
721static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
722 struct timespec *tsreq, struct timespec __user *rmtp)
723{
724 enum alarmtimer_type type = clock2alarm(which_clock);
725 struct alarm alarm;
726 ktime_t exp;
727 int ret = 0;
728 struct restart_block *restart;
729
730 if (!alarmtimer_get_rtcdev())
731 return -ENOTSUPP;
732
733 if (!capable(CAP_WAKE_ALARM))
734 return -EPERM;
735
736 alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
737
738 exp = timespec_to_ktime(*tsreq);
739
740 if (flags != TIMER_ABSTIME) {
741 ktime_t now = alarm_bases[type].gettime();
742 exp = ktime_add(now, exp);
743 }
744
745 if (alarmtimer_do_nsleep(&alarm, exp))
746 goto out;
747
748 if (freezing(current))
749 alarmtimer_freezerset(exp, type);
750
751
752 if (flags == TIMER_ABSTIME) {
753 ret = -ERESTARTNOHAND;
754 goto out;
755 }
756
757 if (rmtp) {
758 ret = update_rmtp(exp, type, rmtp);
759 if (ret <= 0)
760 goto out;
761 }
762
763 restart = ¤t_thread_info()->restart_block;
764 restart->fn = alarm_timer_nsleep_restart;
765 restart->nanosleep.clockid = type;
766 restart->nanosleep.expires = exp.tv64;
767 restart->nanosleep.rmtp = rmtp;
768 ret = -ERESTART_RESTARTBLOCK;
769
770out:
771 return ret;
772}
773
774
775
776static const struct dev_pm_ops alarmtimer_pm_ops = {
777 .suspend = alarmtimer_suspend,
778};
779
780static struct platform_driver alarmtimer_driver = {
781 .driver = {
782 .name = "alarmtimer",
783 .pm = &alarmtimer_pm_ops,
784 }
785};
786
787
788
789
790
791
792
793static int __init alarmtimer_init(void)
794{
795 struct platform_device *pdev;
796 int error = 0;
797 int i;
798 struct k_clock alarm_clock = {
799 .clock_getres = alarm_clock_getres,
800 .clock_get = alarm_clock_get,
801 .timer_create = alarm_timer_create,
802 .timer_set = alarm_timer_set,
803 .timer_del = alarm_timer_del,
804 .timer_get = alarm_timer_get,
805 .nsleep = alarm_timer_nsleep,
806 };
807
808 alarmtimer_rtc_timer_init();
809
810 posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
811 posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
812
813
814 alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
815 alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
816 alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
817 alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
818 for (i = 0; i < ALARM_NUMTYPE; i++) {
819 timerqueue_init_head(&alarm_bases[i].timerqueue);
820 spin_lock_init(&alarm_bases[i].lock);
821 }
822
823 error = alarmtimer_rtc_interface_setup();
824 if (error)
825 return error;
826
827 error = platform_driver_register(&alarmtimer_driver);
828 if (error)
829 goto out_if;
830
831 pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
832 if (IS_ERR(pdev)) {
833 error = PTR_ERR(pdev);
834 goto out_drv;
835 }
836 ws = wakeup_source_register("alarmtimer");
837 return 0;
838
839out_drv:
840 platform_driver_unregister(&alarmtimer_driver);
841out_if:
842 alarmtimer_rtc_interface_remove();
843 return error;
844}
845device_initcall(alarmtimer_init);
846