projects/linux·blob v3.14 · refs

948 lines · 23.4 KiB

1/*
2 * RTC subsystem, interface functions
3 *
4 * Copyright (C) 2005 Tower Technologies
5 * Author: Alessandro Zummo <[email protected]>
6 *
7 * based on arch/arm/common/rtctime.c
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12*/
13
14#include <linux/rtc.h>
15#include <linux/sched.h>
16#include <linux/module.h>
17#include <linux/log2.h>
18#include <linux/workqueue.h>
19
20static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
21static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
22
23static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
24{
25 int err;
26 if (!rtc->ops)
27 err = -ENODEV;
28 else if (!rtc->ops->read_time)
29 err = -EINVAL;
30 else {
31 memset(tm, 0, sizeof(struct rtc_time));
32 err = rtc->ops->read_time(rtc->dev.parent, tm);
33 }
34 return err;
35}
36
37int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
38{
39 int err;
40
41 err = mutex_lock_interruptible(&rtc->ops_lock);
42 if (err)
43 return err;
44
45 err = __rtc_read_time(rtc, tm);
46 mutex_unlock(&rtc->ops_lock);
47 return err;
48}
49EXPORT_SYMBOL_GPL(rtc_read_time);
50
51int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
52{
53 int err;
54
55 err = rtc_valid_tm(tm);
56 if (err != 0)
57 return err;
58
59 err = mutex_lock_interruptible(&rtc->ops_lock);
60 if (err)
61 return err;
62
63 if (!rtc->ops)
64 err = -ENODEV;
65 else if (rtc->ops->set_time)
66 err = rtc->ops->set_time(rtc->dev.parent, tm);
67 else if (rtc->ops->set_mmss) {
68 unsigned long secs;
69 err = rtc_tm_to_time(tm, &secs);
70 if (err == 0)
71 err = rtc->ops->set_mmss(rtc->dev.parent, secs);
72 } else
73 err = -EINVAL;
74
75 pm_stay_awake(rtc->dev.parent);
76 mutex_unlock(&rtc->ops_lock);
77 /* A timer might have just expired */
78 schedule_work(&rtc->irqwork);
79 return err;
80}
81EXPORT_SYMBOL_GPL(rtc_set_time);
82
83int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
84{
85 int err;
86
87 err = mutex_lock_interruptible(&rtc->ops_lock);
88 if (err)
89 return err;
90
91 if (!rtc->ops)
92 err = -ENODEV;
93 else if (rtc->ops->set_mmss)
94 err = rtc->ops->set_mmss(rtc->dev.parent, secs);
95 else if (rtc->ops->read_time && rtc->ops->set_time) {
96 struct rtc_time new, old;
97
98 err = rtc->ops->read_time(rtc->dev.parent, &old);
99 if (err == 0) {
100 rtc_time_to_tm(secs, &new);
101
102 /*
103 * avoid writing when we're going to change the day of
104 * the month. We will retry in the next minute. This
105 * basically means that if the RTC must not drift
106 * by more than 1 minute in 11 minutes.
107 */
108 if (!((old.tm_hour == 23 && old.tm_min == 59) ||
109 (new.tm_hour == 23 && new.tm_min == 59)))
110 err = rtc->ops->set_time(rtc->dev.parent,
111 &new);
112 }
113 } else {
114 err = -EINVAL;
115 }
116
117 pm_stay_awake(rtc->dev.parent);
118 mutex_unlock(&rtc->ops_lock);
119 /* A timer might have just expired */
120 schedule_work(&rtc->irqwork);
121
122 return err;
123}
124EXPORT_SYMBOL_GPL(rtc_set_mmss);
125
126static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
127{
128 int err;
129
130 err = mutex_lock_interruptible(&rtc->ops_lock);
131 if (err)
132 return err;
133
134 if (rtc->ops == NULL)
135 err = -ENODEV;
136 else if (!rtc->ops->read_alarm)
137 err = -EINVAL;
138 else {
139 memset(alarm, 0, sizeof(struct rtc_wkalrm));
140 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
141 }
142
143 mutex_unlock(&rtc->ops_lock);
144 return err;
145}
146
147int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
148{
149 int err;
150 struct rtc_time before, now;
151 int first_time = 1;
152 unsigned long t_now, t_alm;
153 enum { none, day, month, year } missing = none;
154 unsigned days;
155
156 /* The lower level RTC driver may return -1 in some fields,
157 * creating invalid alarm->time values, for reasons like:
158 *
159 * - The hardware may not be capable of filling them in;
160 * many alarms match only on time-of-day fields, not
161 * day/month/year calendar data.
162 *
163 * - Some hardware uses illegal values as "wildcard" match
164 * values, which non-Linux firmware (like a BIOS) may try
165 * to set up as e.g. "alarm 15 minutes after each hour".
166 * Linux uses only oneshot alarms.
167 *
168 * When we see that here, we deal with it by using values from
169 * a current RTC timestamp for any missing (-1) values. The
170 * RTC driver prevents "periodic alarm" modes.
171 *
172 * But this can be racey, because some fields of the RTC timestamp
173 * may have wrapped in the interval since we read the RTC alarm,
174 * which would lead to us inserting inconsistent values in place
175 * of the -1 fields.
176 *
177 * Reading the alarm and timestamp in the reverse sequence
178 * would have the same race condition, and not solve the issue.
179 *
180 * So, we must first read the RTC timestamp,
181 * then read the RTC alarm value,
182 * and then read a second RTC timestamp.
183 *
184 * If any fields of the second timestamp have changed
185 * when compared with the first timestamp, then we know
186 * our timestamp may be inconsistent with that used by
187 * the low-level rtc_read_alarm_internal() function.
188 *
189 * So, when the two timestamps disagree, we just loop and do
190 * the process again to get a fully consistent set of values.
191 *
192 * This could all instead be done in the lower level driver,
193 * but since more than one lower level RTC implementation needs it,
194 * then it's probably best best to do it here instead of there..
195 */
196
197 /* Get the "before" timestamp */
198 err = rtc_read_time(rtc, &before);
199 if (err < 0)
200 return err;
201 do {
202 if (!first_time)
203 memcpy(&before, &now, sizeof(struct rtc_time));
204 first_time = 0;
205
206 /* get the RTC alarm values, which may be incomplete */
207 err = rtc_read_alarm_internal(rtc, alarm);
208 if (err)
209 return err;
210
211 /* full-function RTCs won't have such missing fields */
212 if (rtc_valid_tm(&alarm->time) == 0)
213 return 0;
214
215 /* get the "after" timestamp, to detect wrapped fields */
216 err = rtc_read_time(rtc, &now);
217 if (err < 0)
218 return err;
219
220 /* note that tm_sec is a "don't care" value here: */
221 } while ( before.tm_min != now.tm_min
222 || before.tm_hour != now.tm_hour
223 || before.tm_mon != now.tm_mon
224 || before.tm_year != now.tm_year);
225
226 /* Fill in the missing alarm fields using the timestamp; we
227 * know there's at least one since alarm->time is invalid.
228 */
229 if (alarm->time.tm_sec == -1)
230 alarm->time.tm_sec = now.tm_sec;
231 if (alarm->time.tm_min == -1)
232 alarm->time.tm_min = now.tm_min;
233 if (alarm->time.tm_hour == -1)
234 alarm->time.tm_hour = now.tm_hour;
235
236 /* For simplicity, only support date rollover for now */
237 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
238 alarm->time.tm_mday = now.tm_mday;
239 missing = day;
240 }
241 if ((unsigned)alarm->time.tm_mon >= 12) {
242 alarm->time.tm_mon = now.tm_mon;
243 if (missing == none)
244 missing = month;
245 }
246 if (alarm->time.tm_year == -1) {
247 alarm->time.tm_year = now.tm_year;
248 if (missing == none)
249 missing = year;
250 }
251
252 /* with luck, no rollover is needed */
253 rtc_tm_to_time(&now, &t_now);
254 rtc_tm_to_time(&alarm->time, &t_alm);
255 if (t_now < t_alm)
256 goto done;
257
258 switch (missing) {
259
260 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
261 * that will trigger at 5am will do so at 5am Tuesday, which
262 * could also be in the next month or year. This is a common
263 * case, especially for PCs.
264 */
265 case day:
266 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
267 t_alm += 24 * 60 * 60;
268 rtc_time_to_tm(t_alm, &alarm->time);
269 break;
270
271 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
272 * be next month. An alarm matching on the 30th, 29th, or 28th
273 * may end up in the month after that! Many newer PCs support
274 * this type of alarm.
275 */
276 case month:
277 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
278 do {
279 if (alarm->time.tm_mon < 11)
280 alarm->time.tm_mon++;
281 else {
282 alarm->time.tm_mon = 0;
283 alarm->time.tm_year++;
284 }
285 days = rtc_month_days(alarm->time.tm_mon,
286 alarm->time.tm_year);
287 } while (days < alarm->time.tm_mday);
288 break;
289
290 /* Year rollover ... easy except for leap years! */
291 case year:
292 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
293 do {
294 alarm->time.tm_year++;
295 } while (rtc_valid_tm(&alarm->time) != 0);
296 break;
297
298 default:
299 dev_warn(&rtc->dev, "alarm rollover not handled\n");
300 }
301
302done:
303 return 0;
304}
305
306int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
307{
308 int err;
309
310 err = mutex_lock_interruptible(&rtc->ops_lock);
311 if (err)
312 return err;
313 if (rtc->ops == NULL)
314 err = -ENODEV;
315 else if (!rtc->ops->read_alarm)
316 err = -EINVAL;
317 else {
318 memset(alarm, 0, sizeof(struct rtc_wkalrm));
319 alarm->enabled = rtc->aie_timer.enabled;
320 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
321 }
322 mutex_unlock(&rtc->ops_lock);
323
324 return err;
325}
326EXPORT_SYMBOL_GPL(rtc_read_alarm);
327
328static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
329{
330 struct rtc_time tm;
331 long now, scheduled;
332 int err;
333
334 err = rtc_valid_tm(&alarm->time);
335 if (err)
336 return err;
337 rtc_tm_to_time(&alarm->time, &scheduled);
338
339 /* Make sure we're not setting alarms in the past */
340 err = __rtc_read_time(rtc, &tm);
341 rtc_tm_to_time(&tm, &now);
342 if (scheduled <= now)
343 return -ETIME;
344 /*
345 * XXX - We just checked to make sure the alarm time is not
346 * in the past, but there is still a race window where if
347 * the is alarm set for the next second and the second ticks
348 * over right here, before we set the alarm.
349 */
350
351 if (!rtc->ops)
352 err = -ENODEV;
353 else if (!rtc->ops->set_alarm)
354 err = -EINVAL;
355 else
356 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
357
358 return err;
359}
360
361int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
362{
363 int err;
364
365 err = rtc_valid_tm(&alarm->time);
366 if (err != 0)
367 return err;
368
369 err = mutex_lock_interruptible(&rtc->ops_lock);
370 if (err)
371 return err;
372 if (rtc->aie_timer.enabled)
373 rtc_timer_remove(rtc, &rtc->aie_timer);
374
375 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
376 rtc->aie_timer.period = ktime_set(0, 0);
377 if (alarm->enabled)
378 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
379
380 mutex_unlock(&rtc->ops_lock);
381 return err;
382}
383EXPORT_SYMBOL_GPL(rtc_set_alarm);
384
385/* Called once per device from rtc_device_register */
386int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
387{
388 int err;
389 struct rtc_time now;
390
391 err = rtc_valid_tm(&alarm->time);
392 if (err != 0)
393 return err;
394
395 err = rtc_read_time(rtc, &now);
396 if (err)
397 return err;
398
399 err = mutex_lock_interruptible(&rtc->ops_lock);
400 if (err)
401 return err;
402
403 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
404 rtc->aie_timer.period = ktime_set(0, 0);
405
406 /* Alarm has to be enabled & in the futrure for us to enqueue it */
407 if (alarm->enabled && (rtc_tm_to_ktime(now).tv64 <
408 rtc->aie_timer.node.expires.tv64)) {
409
410 rtc->aie_timer.enabled = 1;
411 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
412 }
413 mutex_unlock(&rtc->ops_lock);
414 return err;
415}
416EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
417
418
419
420int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
421{
422 int err = mutex_lock_interruptible(&rtc->ops_lock);
423 if (err)
424 return err;
425
426 if (rtc->aie_timer.enabled != enabled) {
427 if (enabled)
428 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
429 else
430 rtc_timer_remove(rtc, &rtc->aie_timer);
431 }
432
433 if (err)
434 /* nothing */;
435 else if (!rtc->ops)
436 err = -ENODEV;
437 else if (!rtc->ops->alarm_irq_enable)
438 err = -EINVAL;
439 else
440 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
441
442 mutex_unlock(&rtc->ops_lock);
443 return err;
444}
445EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
446
447int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
448{
449 int err = mutex_lock_interruptible(&rtc->ops_lock);
450 if (err)
451 return err;
452
453#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
454 if (enabled == 0 && rtc->uie_irq_active) {
455 mutex_unlock(&rtc->ops_lock);
456 return rtc_dev_update_irq_enable_emul(rtc, 0);
457 }
458#endif
459 /* make sure we're changing state */
460 if (rtc->uie_rtctimer.enabled == enabled)
461 goto out;
462
463 if (rtc->uie_unsupported) {
464 err = -EINVAL;
465 goto out;
466 }
467
468 if (enabled) {
469 struct rtc_time tm;
470 ktime_t now, onesec;
471
472 __rtc_read_time(rtc, &tm);
473 onesec = ktime_set(1, 0);
474 now = rtc_tm_to_ktime(tm);
475 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
476 rtc->uie_rtctimer.period = ktime_set(1, 0);
477 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
478 } else
479 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
480
481out:
482 mutex_unlock(&rtc->ops_lock);
483#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
484 /*
485 * Enable emulation if the driver did not provide
486 * the update_irq_enable function pointer or if returned
487 * -EINVAL to signal that it has been configured without
488 * interrupts or that are not available at the moment.
489 */
490 if (err == -EINVAL)
491 err = rtc_dev_update_irq_enable_emul(rtc, enabled);
492#endif
493 return err;
494
495}
496EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
497
498
499/**
500 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
501 * @rtc: pointer to the rtc device
502 *
503 * This function is called when an AIE, UIE or PIE mode interrupt
504 * has occurred (or been emulated).
505 *
506 * Triggers the registered irq_task function callback.
507 */
508void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
509{
510 unsigned long flags;
511
512 /* mark one irq of the appropriate mode */
513 spin_lock_irqsave(&rtc->irq_lock, flags);
514 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
515 spin_unlock_irqrestore(&rtc->irq_lock, flags);
516
517 /* call the task func */
518 spin_lock_irqsave(&rtc->irq_task_lock, flags);
519 if (rtc->irq_task)
520 rtc->irq_task->func(rtc->irq_task->private_data);
521 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
522
523 wake_up_interruptible(&rtc->irq_queue);
524 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
525}
526
527
528/**
529 * rtc_aie_update_irq - AIE mode rtctimer hook
530 * @private: pointer to the rtc_device
531 *
532 * This functions is called when the aie_timer expires.
533 */
534void rtc_aie_update_irq(void *private)
535{
536 struct rtc_device *rtc = (struct rtc_device *)private;
537 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
538}
539
540
541/**
542 * rtc_uie_update_irq - UIE mode rtctimer hook
543 * @private: pointer to the rtc_device
544 *
545 * This functions is called when the uie_timer expires.
546 */
547void rtc_uie_update_irq(void *private)
548{
549 struct rtc_device *rtc = (struct rtc_device *)private;
550 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
551}
552
553
554/**
555 * rtc_pie_update_irq - PIE mode hrtimer hook
556 * @timer: pointer to the pie mode hrtimer
557 *
558 * This function is used to emulate PIE mode interrupts
559 * using an hrtimer. This function is called when the periodic
560 * hrtimer expires.
561 */
562enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
563{
564 struct rtc_device *rtc;
565 ktime_t period;
566 int count;
567 rtc = container_of(timer, struct rtc_device, pie_timer);
568
569 period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
570 count = hrtimer_forward_now(timer, period);
571
572 rtc_handle_legacy_irq(rtc, count, RTC_PF);
573
574 return HRTIMER_RESTART;
575}
576
577/**
578 * rtc_update_irq - Triggered when a RTC interrupt occurs.
579 * @rtc: the rtc device
580 * @num: how many irqs are being reported (usually one)
581 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
582 * Context: any
583 */
584void rtc_update_irq(struct rtc_device *rtc,
585 unsigned long num, unsigned long events)
586{
587 pm_stay_awake(rtc->dev.parent);
588 schedule_work(&rtc->irqwork);
589}
590EXPORT_SYMBOL_GPL(rtc_update_irq);
591
592static int __rtc_match(struct device *dev, const void *data)
593{
594 const char *name = data;
595
596 if (strcmp(dev_name(dev), name) == 0)
597 return 1;
598 return 0;
599}
600
601struct rtc_device *rtc_class_open(const char *name)
602{
603 struct device *dev;
604 struct rtc_device *rtc = NULL;
605
606 dev = class_find_device(rtc_class, NULL, name, __rtc_match);
607 if (dev)
608 rtc = to_rtc_device(dev);
609
610 if (rtc) {
611 if (!try_module_get(rtc->owner)) {
612 put_device(dev);
613 rtc = NULL;
614 }
615 }
616
617 return rtc;
618}
619EXPORT_SYMBOL_GPL(rtc_class_open);
620
621void rtc_class_close(struct rtc_device *rtc)
622{
623 module_put(rtc->owner);
624 put_device(&rtc->dev);
625}
626EXPORT_SYMBOL_GPL(rtc_class_close);
627
628int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
629{
630 int retval = -EBUSY;
631
632 if (task == NULL || task->func == NULL)
633 return -EINVAL;
634
635 /* Cannot register while the char dev is in use */
636 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
637 return -EBUSY;
638
639 spin_lock_irq(&rtc->irq_task_lock);
640 if (rtc->irq_task == NULL) {
641 rtc->irq_task = task;
642 retval = 0;
643 }
644 spin_unlock_irq(&rtc->irq_task_lock);
645
646 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
647
648 return retval;
649}
650EXPORT_SYMBOL_GPL(rtc_irq_register);
651
652void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
653{
654 spin_lock_irq(&rtc->irq_task_lock);
655 if (rtc->irq_task == task)
656 rtc->irq_task = NULL;
657 spin_unlock_irq(&rtc->irq_task_lock);
658}
659EXPORT_SYMBOL_GPL(rtc_irq_unregister);
660
661static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
662{
663 /*
664 * We always cancel the timer here first, because otherwise
665 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
666 * when we manage to start the timer before the callback
667 * returns HRTIMER_RESTART.
668 *
669 * We cannot use hrtimer_cancel() here as a running callback
670 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
671 * would spin forever.
672 */
673 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
674 return -1;
675
676 if (enabled) {
677 ktime_t period = ktime_set(0, NSEC_PER_SEC / rtc->irq_freq);
678
679 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
680 }
681 return 0;
682}
683
684/**
685 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
686 * @rtc: the rtc device
687 * @task: currently registered with rtc_irq_register()
688 * @enabled: true to enable periodic IRQs
689 * Context: any
690 *
691 * Note that rtc_irq_set_freq() should previously have been used to
692 * specify the desired frequency of periodic IRQ task->func() callbacks.
693 */
694int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
695{
696 int err = 0;
697 unsigned long flags;
698
699retry:
700 spin_lock_irqsave(&rtc->irq_task_lock, flags);
701 if (rtc->irq_task != NULL && task == NULL)
702 err = -EBUSY;
703 else if (rtc->irq_task != task)
704 err = -EACCES;
705 else {
706 if (rtc_update_hrtimer(rtc, enabled) < 0) {
707 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
708 cpu_relax();
709 goto retry;
710 }
711 rtc->pie_enabled = enabled;
712 }
713 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
714 return err;
715}
716EXPORT_SYMBOL_GPL(rtc_irq_set_state);
717
718/**
719 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
720 * @rtc: the rtc device
721 * @task: currently registered with rtc_irq_register()
722 * @freq: positive frequency with which task->func() will be called
723 * Context: any
724 *
725 * Note that rtc_irq_set_state() is used to enable or disable the
726 * periodic IRQs.
727 */
728int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
729{
730 int err = 0;
731 unsigned long flags;
732
733 if (freq <= 0 || freq > RTC_MAX_FREQ)
734 return -EINVAL;
735retry:
736 spin_lock_irqsave(&rtc->irq_task_lock, flags);
737 if (rtc->irq_task != NULL && task == NULL)
738 err = -EBUSY;
739 else if (rtc->irq_task != task)
740 err = -EACCES;
741 else {
742 rtc->irq_freq = freq;
743 if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) {
744 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
745 cpu_relax();
746 goto retry;
747 }
748 }
749 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
750 return err;
751}
752EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
753
754/**
755 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
756 * @rtc rtc device
757 * @timer timer being added.
758 *
759 * Enqueues a timer onto the rtc devices timerqueue and sets
760 * the next alarm event appropriately.
761 *
762 * Sets the enabled bit on the added timer.
763 *
764 * Must hold ops_lock for proper serialization of timerqueue
765 */
766static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
767{
768 timer->enabled = 1;
769 timerqueue_add(&rtc->timerqueue, &timer->node);
770 if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) {
771 struct rtc_wkalrm alarm;
772 int err;
773 alarm.time = rtc_ktime_to_tm(timer->node.expires);
774 alarm.enabled = 1;
775 err = __rtc_set_alarm(rtc, &alarm);
776 if (err == -ETIME) {
777 pm_stay_awake(rtc->dev.parent);
778 schedule_work(&rtc->irqwork);
779 } else if (err) {
780 timerqueue_del(&rtc->timerqueue, &timer->node);
781 timer->enabled = 0;
782 return err;
783 }
784 }
785 return 0;
786}
787
788static void rtc_alarm_disable(struct rtc_device *rtc)
789{
790 if (!rtc->ops || !rtc->ops->alarm_irq_enable)
791 return;
792
793 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
794}
795
796/**
797 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
798 * @rtc rtc device
799 * @timer timer being removed.
800 *
801 * Removes a timer onto the rtc devices timerqueue and sets
802 * the next alarm event appropriately.
803 *
804 * Clears the enabled bit on the removed timer.
805 *
806 * Must hold ops_lock for proper serialization of timerqueue
807 */
808static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
809{
810 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
811 timerqueue_del(&rtc->timerqueue, &timer->node);
812 timer->enabled = 0;
813 if (next == &timer->node) {
814 struct rtc_wkalrm alarm;
815 int err;
816 next = timerqueue_getnext(&rtc->timerqueue);
817 if (!next) {
818 rtc_alarm_disable(rtc);
819 return;
820 }
821 alarm.time = rtc_ktime_to_tm(next->expires);
822 alarm.enabled = 1;
823 err = __rtc_set_alarm(rtc, &alarm);
824 if (err == -ETIME) {
825 pm_stay_awake(rtc->dev.parent);
826 schedule_work(&rtc->irqwork);
827 }
828 }
829}
830
831/**
832 * rtc_timer_do_work - Expires rtc timers
833 * @rtc rtc device
834 * @timer timer being removed.
835 *
836 * Expires rtc timers. Reprograms next alarm event if needed.
837 * Called via worktask.
838 *
839 * Serializes access to timerqueue via ops_lock mutex
840 */
841void rtc_timer_do_work(struct work_struct *work)
842{
843 struct rtc_timer *timer;
844 struct timerqueue_node *next;
845 ktime_t now;
846 struct rtc_time tm;
847
848 struct rtc_device *rtc =
849 container_of(work, struct rtc_device, irqwork);
850
851 mutex_lock(&rtc->ops_lock);
852again:
853 __rtc_read_time(rtc, &tm);
854 now = rtc_tm_to_ktime(tm);
855 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
856 if (next->expires.tv64 > now.tv64)
857 break;
858
859 /* expire timer */
860 timer = container_of(next, struct rtc_timer, node);
861 timerqueue_del(&rtc->timerqueue, &timer->node);
862 timer->enabled = 0;
863 if (timer->task.func)
864 timer->task.func(timer->task.private_data);
865
866 /* Re-add/fwd periodic timers */
867 if (ktime_to_ns(timer->period)) {
868 timer->node.expires = ktime_add(timer->node.expires,
869 timer->period);
870 timer->enabled = 1;
871 timerqueue_add(&rtc->timerqueue, &timer->node);
872 }
873 }
874
875 /* Set next alarm */
876 if (next) {
877 struct rtc_wkalrm alarm;
878 int err;
879 alarm.time = rtc_ktime_to_tm(next->expires);
880 alarm.enabled = 1;
881 err = __rtc_set_alarm(rtc, &alarm);
882 if (err == -ETIME)
883 goto again;
884 } else
885 rtc_alarm_disable(rtc);
886
887 pm_relax(rtc->dev.parent);
888 mutex_unlock(&rtc->ops_lock);
889}
890
891
892/* rtc_timer_init - Initializes an rtc_timer
893 * @timer: timer to be intiialized
894 * @f: function pointer to be called when timer fires
895 * @data: private data passed to function pointer
896 *
897 * Kernel interface to initializing an rtc_timer.
898 */
899void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data)
900{
901 timerqueue_init(&timer->node);
902 timer->enabled = 0;
903 timer->task.func = f;
904 timer->task.private_data = data;
905}
906
907/* rtc_timer_start - Sets an rtc_timer to fire in the future
908 * @ rtc: rtc device to be used
909 * @ timer: timer being set
910 * @ expires: time at which to expire the timer
911 * @ period: period that the timer will recur
912 *
913 * Kernel interface to set an rtc_timer
914 */
915int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
916 ktime_t expires, ktime_t period)
917{
918 int ret = 0;
919 mutex_lock(&rtc->ops_lock);
920 if (timer->enabled)
921 rtc_timer_remove(rtc, timer);
922
923 timer->node.expires = expires;
924 timer->period = period;
925
926 ret = rtc_timer_enqueue(rtc, timer);
927
928 mutex_unlock(&rtc->ops_lock);
929 return ret;
930}
931
932/* rtc_timer_cancel - Stops an rtc_timer
933 * @ rtc: rtc device to be used
934 * @ timer: timer being set
935 *
936 * Kernel interface to cancel an rtc_timer
937 */
938int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
939{
940 int ret = 0;
941 mutex_lock(&rtc->ops_lock);
942 if (timer->enabled)
943 rtc_timer_remove(rtc, timer);
944 mutex_unlock(&rtc->ops_lock);
945 return ret;
946}
947
948