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1/*
2 * RTC subsystem, interface functions
3 *
4 * Copyright (C) 2005 Tower Technologies
5 * Author: Alessandro Zummo <a.zummo@towertech.it>
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 if (unlikely(IS_ERR_OR_NULL(rtc)))
588 return;
589
590 pm_stay_awake(rtc->dev.parent);
591 schedule_work(&rtc->irqwork);
592}
593EXPORT_SYMBOL_GPL(rtc_update_irq);
594
595static int __rtc_match(struct device *dev, const void *data)
596{
597 const char *name = data;
598
599 if (strcmp(dev_name(dev), name) == 0)
600 return 1;
601 return 0;
602}
603
604struct rtc_device *rtc_class_open(const char *name)
605{
606 struct device *dev;
607 struct rtc_device *rtc = NULL;
608
609 dev = class_find_device(rtc_class, NULL, name, __rtc_match);
610 if (dev)
611 rtc = to_rtc_device(dev);
612
613 if (rtc) {
614 if (!try_module_get(rtc->owner)) {
615 put_device(dev);
616 rtc = NULL;
617 }
618 }
619
620 return rtc;
621}
622EXPORT_SYMBOL_GPL(rtc_class_open);
623
624void rtc_class_close(struct rtc_device *rtc)
625{
626 module_put(rtc->owner);
627 put_device(&rtc->dev);
628}
629EXPORT_SYMBOL_GPL(rtc_class_close);
630
631int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
632{
633 int retval = -EBUSY;
634
635 if (task == NULL || task->func == NULL)
636 return -EINVAL;
637
638 /* Cannot register while the char dev is in use */
639 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
640 return -EBUSY;
641
642 spin_lock_irq(&rtc->irq_task_lock);
643 if (rtc->irq_task == NULL) {
644 rtc->irq_task = task;
645 retval = 0;
646 }
647 spin_unlock_irq(&rtc->irq_task_lock);
648
649 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
650
651 return retval;
652}
653EXPORT_SYMBOL_GPL(rtc_irq_register);
654
655void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
656{
657 spin_lock_irq(&rtc->irq_task_lock);
658 if (rtc->irq_task == task)
659 rtc->irq_task = NULL;
660 spin_unlock_irq(&rtc->irq_task_lock);
661}
662EXPORT_SYMBOL_GPL(rtc_irq_unregister);
663
664static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
665{
666 /*
667 * We always cancel the timer here first, because otherwise
668 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
669 * when we manage to start the timer before the callback
670 * returns HRTIMER_RESTART.
671 *
672 * We cannot use hrtimer_cancel() here as a running callback
673 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
674 * would spin forever.
675 */
676 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
677 return -1;
678
679 if (enabled) {
680 ktime_t period = ktime_set(0, NSEC_PER_SEC / rtc->irq_freq);
681
682 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
683 }
684 return 0;
685}
686
687/**
688 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
689 * @rtc: the rtc device
690 * @task: currently registered with rtc_irq_register()
691 * @enabled: true to enable periodic IRQs
692 * Context: any
693 *
694 * Note that rtc_irq_set_freq() should previously have been used to
695 * specify the desired frequency of periodic IRQ task->func() callbacks.
696 */
697int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
698{
699 int err = 0;
700 unsigned long flags;
701
702retry:
703 spin_lock_irqsave(&rtc->irq_task_lock, flags);
704 if (rtc->irq_task != NULL && task == NULL)
705 err = -EBUSY;
706 else if (rtc->irq_task != task)
707 err = -EACCES;
708 else {
709 if (rtc_update_hrtimer(rtc, enabled) < 0) {
710 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
711 cpu_relax();
712 goto retry;
713 }
714 rtc->pie_enabled = enabled;
715 }
716 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
717 return err;
718}
719EXPORT_SYMBOL_GPL(rtc_irq_set_state);
720
721/**
722 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
723 * @rtc: the rtc device
724 * @task: currently registered with rtc_irq_register()
725 * @freq: positive frequency with which task->func() will be called
726 * Context: any
727 *
728 * Note that rtc_irq_set_state() is used to enable or disable the
729 * periodic IRQs.
730 */
731int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
732{
733 int err = 0;
734 unsigned long flags;
735
736 if (freq <= 0 || freq > RTC_MAX_FREQ)
737 return -EINVAL;
738retry:
739 spin_lock_irqsave(&rtc->irq_task_lock, flags);
740 if (rtc->irq_task != NULL && task == NULL)
741 err = -EBUSY;
742 else if (rtc->irq_task != task)
743 err = -EACCES;
744 else {
745 rtc->irq_freq = freq;
746 if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) {
747 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
748 cpu_relax();
749 goto retry;
750 }
751 }
752 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
753 return err;
754}
755EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
756
757/**
758 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
759 * @rtc rtc device
760 * @timer timer being added.
761 *
762 * Enqueues a timer onto the rtc devices timerqueue and sets
763 * the next alarm event appropriately.
764 *
765 * Sets the enabled bit on the added timer.
766 *
767 * Must hold ops_lock for proper serialization of timerqueue
768 */
769static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
770{
771 timer->enabled = 1;
772 timerqueue_add(&rtc->timerqueue, &timer->node);
773 if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) {
774 struct rtc_wkalrm alarm;
775 int err;
776 alarm.time = rtc_ktime_to_tm(timer->node.expires);
777 alarm.enabled = 1;
778 err = __rtc_set_alarm(rtc, &alarm);
779 if (err == -ETIME) {
780 pm_stay_awake(rtc->dev.parent);
781 schedule_work(&rtc->irqwork);
782 } else if (err) {
783 timerqueue_del(&rtc->timerqueue, &timer->node);
784 timer->enabled = 0;
785 return err;
786 }
787 }
788 return 0;
789}
790
791static void rtc_alarm_disable(struct rtc_device *rtc)
792{
793 if (!rtc->ops || !rtc->ops->alarm_irq_enable)
794 return;
795
796 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
797}
798
799/**
800 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
801 * @rtc rtc device
802 * @timer timer being removed.
803 *
804 * Removes a timer onto the rtc devices timerqueue and sets
805 * the next alarm event appropriately.
806 *
807 * Clears the enabled bit on the removed timer.
808 *
809 * Must hold ops_lock for proper serialization of timerqueue
810 */
811static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
812{
813 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
814 timerqueue_del(&rtc->timerqueue, &timer->node);
815 timer->enabled = 0;
816 if (next == &timer->node) {
817 struct rtc_wkalrm alarm;
818 int err;
819 next = timerqueue_getnext(&rtc->timerqueue);
820 if (!next) {
821 rtc_alarm_disable(rtc);
822 return;
823 }
824 alarm.time = rtc_ktime_to_tm(next->expires);
825 alarm.enabled = 1;
826 err = __rtc_set_alarm(rtc, &alarm);
827 if (err == -ETIME) {
828 pm_stay_awake(rtc->dev.parent);
829 schedule_work(&rtc->irqwork);
830 }
831 }
832}
833
834/**
835 * rtc_timer_do_work - Expires rtc timers
836 * @rtc rtc device
837 * @timer timer being removed.
838 *
839 * Expires rtc timers. Reprograms next alarm event if needed.
840 * Called via worktask.
841 *
842 * Serializes access to timerqueue via ops_lock mutex
843 */
844void rtc_timer_do_work(struct work_struct *work)
845{
846 struct rtc_timer *timer;
847 struct timerqueue_node *next;
848 ktime_t now;
849 struct rtc_time tm;
850
851 struct rtc_device *rtc =
852 container_of(work, struct rtc_device, irqwork);
853
854 mutex_lock(&rtc->ops_lock);
855again:
856 __rtc_read_time(rtc, &tm);
857 now = rtc_tm_to_ktime(tm);
858 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
859 if (next->expires.tv64 > now.tv64)
860 break;
861
862 /* expire timer */
863 timer = container_of(next, struct rtc_timer, node);
864 timerqueue_del(&rtc->timerqueue, &timer->node);
865 timer->enabled = 0;
866 if (timer->task.func)
867 timer->task.func(timer->task.private_data);
868
869 /* Re-add/fwd periodic timers */
870 if (ktime_to_ns(timer->period)) {
871 timer->node.expires = ktime_add(timer->node.expires,
872 timer->period);
873 timer->enabled = 1;
874 timerqueue_add(&rtc->timerqueue, &timer->node);
875 }
876 }
877
878 /* Set next alarm */
879 if (next) {
880 struct rtc_wkalrm alarm;
881 int err;
882 alarm.time = rtc_ktime_to_tm(next->expires);
883 alarm.enabled = 1;
884 err = __rtc_set_alarm(rtc, &alarm);
885 if (err == -ETIME)
886 goto again;
887 } else
888 rtc_alarm_disable(rtc);
889
890 pm_relax(rtc->dev.parent);
891 mutex_unlock(&rtc->ops_lock);
892}
893
894
895/* rtc_timer_init - Initializes an rtc_timer
896 * @timer: timer to be intiialized
897 * @f: function pointer to be called when timer fires
898 * @data: private data passed to function pointer
899 *
900 * Kernel interface to initializing an rtc_timer.
901 */
902void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data)
903{
904 timerqueue_init(&timer->node);
905 timer->enabled = 0;
906 timer->task.func = f;
907 timer->task.private_data = data;
908}
909
910/* rtc_timer_start - Sets an rtc_timer to fire in the future
911 * @ rtc: rtc device to be used
912 * @ timer: timer being set
913 * @ expires: time at which to expire the timer
914 * @ period: period that the timer will recur
915 *
916 * Kernel interface to set an rtc_timer
917 */
918int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
919 ktime_t expires, ktime_t period)
920{
921 int ret = 0;
922 mutex_lock(&rtc->ops_lock);
923 if (timer->enabled)
924 rtc_timer_remove(rtc, timer);
925
926 timer->node.expires = expires;
927 timer->period = period;
928
929 ret = rtc_timer_enqueue(rtc, timer);
930
931 mutex_unlock(&rtc->ops_lock);
932 return ret;
933}
934
935/* rtc_timer_cancel - Stops an rtc_timer
936 * @ rtc: rtc device to be used
937 * @ timer: timer being set
938 *
939 * Kernel interface to cancel an rtc_timer
940 */
941int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
942{
943 int ret = 0;
944 mutex_lock(&rtc->ops_lock);
945 if (timer->enabled)
946 rtc_timer_remove(rtc, timer);
947 mutex_unlock(&rtc->ops_lock);
948 return ret;
949}
950
951
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * RTC subsystem, interface functions
4 *
5 * Copyright (C) 2005 Tower Technologies
6 * Author: Alessandro Zummo <a.zummo@towertech.it>
7 *
8 * based on arch/arm/common/rtctime.c
9 */
10
11#include <linux/rtc.h>
12#include <linux/sched.h>
13#include <linux/module.h>
14#include <linux/log2.h>
15#include <linux/workqueue.h>
16
17#define CREATE_TRACE_POINTS
18#include <trace/events/rtc.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 void rtc_add_offset(struct rtc_device *rtc, struct rtc_time *tm)
24{
25 time64_t secs;
26
27 if (!rtc->offset_secs)
28 return;
29
30 secs = rtc_tm_to_time64(tm);
31
32 /*
33 * Since the reading time values from RTC device are always in the RTC
34 * original valid range, but we need to skip the overlapped region
35 * between expanded range and original range, which is no need to add
36 * the offset.
37 */
38 if ((rtc->start_secs > rtc->range_min && secs >= rtc->start_secs) ||
39 (rtc->start_secs < rtc->range_min &&
40 secs <= (rtc->start_secs + rtc->range_max - rtc->range_min)))
41 return;
42
43 rtc_time64_to_tm(secs + rtc->offset_secs, tm);
44}
45
46static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm)
47{
48 time64_t secs;
49
50 if (!rtc->offset_secs)
51 return;
52
53 secs = rtc_tm_to_time64(tm);
54
55 /*
56 * If the setting time values are in the valid range of RTC hardware
57 * device, then no need to subtract the offset when setting time to RTC
58 * device. Otherwise we need to subtract the offset to make the time
59 * values are valid for RTC hardware device.
60 */
61 if (secs >= rtc->range_min && secs <= rtc->range_max)
62 return;
63
64 rtc_time64_to_tm(secs - rtc->offset_secs, tm);
65}
66
67static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm)
68{
69 if (rtc->range_min != rtc->range_max) {
70 time64_t time = rtc_tm_to_time64(tm);
71 time64_t range_min = rtc->set_start_time ? rtc->start_secs :
72 rtc->range_min;
73 time64_t range_max = rtc->set_start_time ?
74 (rtc->start_secs + rtc->range_max - rtc->range_min) :
75 rtc->range_max;
76
77 if (time < range_min || time > range_max)
78 return -ERANGE;
79 }
80
81 return 0;
82}
83
84static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
85{
86 int err;
87
88 if (!rtc->ops) {
89 err = -ENODEV;
90 } else if (!rtc->ops->read_time) {
91 err = -EINVAL;
92 } else {
93 memset(tm, 0, sizeof(struct rtc_time));
94 err = rtc->ops->read_time(rtc->dev.parent, tm);
95 if (err < 0) {
96 dev_dbg(&rtc->dev, "read_time: fail to read: %d\n",
97 err);
98 return err;
99 }
100
101 rtc_add_offset(rtc, tm);
102
103 err = rtc_valid_tm(tm);
104 if (err < 0)
105 dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n");
106 }
107 return err;
108}
109
110int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
111{
112 int err;
113
114 err = mutex_lock_interruptible(&rtc->ops_lock);
115 if (err)
116 return err;
117
118 err = __rtc_read_time(rtc, tm);
119 mutex_unlock(&rtc->ops_lock);
120
121 trace_rtc_read_time(rtc_tm_to_time64(tm), err);
122 return err;
123}
124EXPORT_SYMBOL_GPL(rtc_read_time);
125
126int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
127{
128 int err;
129
130 err = rtc_valid_tm(tm);
131 if (err != 0)
132 return err;
133
134 err = rtc_valid_range(rtc, tm);
135 if (err)
136 return err;
137
138 rtc_subtract_offset(rtc, tm);
139
140 err = mutex_lock_interruptible(&rtc->ops_lock);
141 if (err)
142 return err;
143
144 if (!rtc->ops)
145 err = -ENODEV;
146 else if (rtc->ops->set_time)
147 err = rtc->ops->set_time(rtc->dev.parent, tm);
148 else
149 err = -EINVAL;
150
151 pm_stay_awake(rtc->dev.parent);
152 mutex_unlock(&rtc->ops_lock);
153 /* A timer might have just expired */
154 schedule_work(&rtc->irqwork);
155
156 trace_rtc_set_time(rtc_tm_to_time64(tm), err);
157 return err;
158}
159EXPORT_SYMBOL_GPL(rtc_set_time);
160
161static int rtc_read_alarm_internal(struct rtc_device *rtc,
162 struct rtc_wkalrm *alarm)
163{
164 int err;
165
166 err = mutex_lock_interruptible(&rtc->ops_lock);
167 if (err)
168 return err;
169
170 if (!rtc->ops) {
171 err = -ENODEV;
172 } else if (!rtc->ops->read_alarm) {
173 err = -EINVAL;
174 } else {
175 alarm->enabled = 0;
176 alarm->pending = 0;
177 alarm->time.tm_sec = -1;
178 alarm->time.tm_min = -1;
179 alarm->time.tm_hour = -1;
180 alarm->time.tm_mday = -1;
181 alarm->time.tm_mon = -1;
182 alarm->time.tm_year = -1;
183 alarm->time.tm_wday = -1;
184 alarm->time.tm_yday = -1;
185 alarm->time.tm_isdst = -1;
186 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
187 }
188
189 mutex_unlock(&rtc->ops_lock);
190
191 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
192 return err;
193}
194
195int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
196{
197 int err;
198 struct rtc_time before, now;
199 int first_time = 1;
200 time64_t t_now, t_alm;
201 enum { none, day, month, year } missing = none;
202 unsigned int days;
203
204 /* The lower level RTC driver may return -1 in some fields,
205 * creating invalid alarm->time values, for reasons like:
206 *
207 * - The hardware may not be capable of filling them in;
208 * many alarms match only on time-of-day fields, not
209 * day/month/year calendar data.
210 *
211 * - Some hardware uses illegal values as "wildcard" match
212 * values, which non-Linux firmware (like a BIOS) may try
213 * to set up as e.g. "alarm 15 minutes after each hour".
214 * Linux uses only oneshot alarms.
215 *
216 * When we see that here, we deal with it by using values from
217 * a current RTC timestamp for any missing (-1) values. The
218 * RTC driver prevents "periodic alarm" modes.
219 *
220 * But this can be racey, because some fields of the RTC timestamp
221 * may have wrapped in the interval since we read the RTC alarm,
222 * which would lead to us inserting inconsistent values in place
223 * of the -1 fields.
224 *
225 * Reading the alarm and timestamp in the reverse sequence
226 * would have the same race condition, and not solve the issue.
227 *
228 * So, we must first read the RTC timestamp,
229 * then read the RTC alarm value,
230 * and then read a second RTC timestamp.
231 *
232 * If any fields of the second timestamp have changed
233 * when compared with the first timestamp, then we know
234 * our timestamp may be inconsistent with that used by
235 * the low-level rtc_read_alarm_internal() function.
236 *
237 * So, when the two timestamps disagree, we just loop and do
238 * the process again to get a fully consistent set of values.
239 *
240 * This could all instead be done in the lower level driver,
241 * but since more than one lower level RTC implementation needs it,
242 * then it's probably best best to do it here instead of there..
243 */
244
245 /* Get the "before" timestamp */
246 err = rtc_read_time(rtc, &before);
247 if (err < 0)
248 return err;
249 do {
250 if (!first_time)
251 memcpy(&before, &now, sizeof(struct rtc_time));
252 first_time = 0;
253
254 /* get the RTC alarm values, which may be incomplete */
255 err = rtc_read_alarm_internal(rtc, alarm);
256 if (err)
257 return err;
258
259 /* full-function RTCs won't have such missing fields */
260 if (rtc_valid_tm(&alarm->time) == 0) {
261 rtc_add_offset(rtc, &alarm->time);
262 return 0;
263 }
264
265 /* get the "after" timestamp, to detect wrapped fields */
266 err = rtc_read_time(rtc, &now);
267 if (err < 0)
268 return err;
269
270 /* note that tm_sec is a "don't care" value here: */
271 } while (before.tm_min != now.tm_min ||
272 before.tm_hour != now.tm_hour ||
273 before.tm_mon != now.tm_mon ||
274 before.tm_year != now.tm_year);
275
276 /* Fill in the missing alarm fields using the timestamp; we
277 * know there's at least one since alarm->time is invalid.
278 */
279 if (alarm->time.tm_sec == -1)
280 alarm->time.tm_sec = now.tm_sec;
281 if (alarm->time.tm_min == -1)
282 alarm->time.tm_min = now.tm_min;
283 if (alarm->time.tm_hour == -1)
284 alarm->time.tm_hour = now.tm_hour;
285
286 /* For simplicity, only support date rollover for now */
287 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
288 alarm->time.tm_mday = now.tm_mday;
289 missing = day;
290 }
291 if ((unsigned int)alarm->time.tm_mon >= 12) {
292 alarm->time.tm_mon = now.tm_mon;
293 if (missing == none)
294 missing = month;
295 }
296 if (alarm->time.tm_year == -1) {
297 alarm->time.tm_year = now.tm_year;
298 if (missing == none)
299 missing = year;
300 }
301
302 /* Can't proceed if alarm is still invalid after replacing
303 * missing fields.
304 */
305 err = rtc_valid_tm(&alarm->time);
306 if (err)
307 goto done;
308
309 /* with luck, no rollover is needed */
310 t_now = rtc_tm_to_time64(&now);
311 t_alm = rtc_tm_to_time64(&alarm->time);
312 if (t_now < t_alm)
313 goto done;
314
315 switch (missing) {
316 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
317 * that will trigger at 5am will do so at 5am Tuesday, which
318 * could also be in the next month or year. This is a common
319 * case, especially for PCs.
320 */
321 case day:
322 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
323 t_alm += 24 * 60 * 60;
324 rtc_time64_to_tm(t_alm, &alarm->time);
325 break;
326
327 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
328 * be next month. An alarm matching on the 30th, 29th, or 28th
329 * may end up in the month after that! Many newer PCs support
330 * this type of alarm.
331 */
332 case month:
333 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
334 do {
335 if (alarm->time.tm_mon < 11) {
336 alarm->time.tm_mon++;
337 } else {
338 alarm->time.tm_mon = 0;
339 alarm->time.tm_year++;
340 }
341 days = rtc_month_days(alarm->time.tm_mon,
342 alarm->time.tm_year);
343 } while (days < alarm->time.tm_mday);
344 break;
345
346 /* Year rollover ... easy except for leap years! */
347 case year:
348 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
349 do {
350 alarm->time.tm_year++;
351 } while (!is_leap_year(alarm->time.tm_year + 1900) &&
352 rtc_valid_tm(&alarm->time) != 0);
353 break;
354
355 default:
356 dev_warn(&rtc->dev, "alarm rollover not handled\n");
357 }
358
359 err = rtc_valid_tm(&alarm->time);
360
361done:
362 if (err)
363 dev_warn(&rtc->dev, "invalid alarm value: %ptR\n",
364 &alarm->time);
365
366 return err;
367}
368
369int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
370{
371 int err;
372
373 err = mutex_lock_interruptible(&rtc->ops_lock);
374 if (err)
375 return err;
376 if (!rtc->ops) {
377 err = -ENODEV;
378 } else if (!rtc->ops->read_alarm) {
379 err = -EINVAL;
380 } else {
381 memset(alarm, 0, sizeof(struct rtc_wkalrm));
382 alarm->enabled = rtc->aie_timer.enabled;
383 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
384 }
385 mutex_unlock(&rtc->ops_lock);
386
387 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
388 return err;
389}
390EXPORT_SYMBOL_GPL(rtc_read_alarm);
391
392static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
393{
394 struct rtc_time tm;
395 time64_t now, scheduled;
396 int err;
397
398 err = rtc_valid_tm(&alarm->time);
399 if (err)
400 return err;
401
402 scheduled = rtc_tm_to_time64(&alarm->time);
403
404 /* Make sure we're not setting alarms in the past */
405 err = __rtc_read_time(rtc, &tm);
406 if (err)
407 return err;
408 now = rtc_tm_to_time64(&tm);
409 if (scheduled <= now)
410 return -ETIME;
411 /*
412 * XXX - We just checked to make sure the alarm time is not
413 * in the past, but there is still a race window where if
414 * the is alarm set for the next second and the second ticks
415 * over right here, before we set the alarm.
416 */
417
418 rtc_subtract_offset(rtc, &alarm->time);
419
420 if (!rtc->ops)
421 err = -ENODEV;
422 else if (!rtc->ops->set_alarm)
423 err = -EINVAL;
424 else
425 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
426
427 trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
428 return err;
429}
430
431int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
432{
433 int err;
434
435 if (!rtc->ops)
436 return -ENODEV;
437 else if (!rtc->ops->set_alarm)
438 return -EINVAL;
439
440 err = rtc_valid_tm(&alarm->time);
441 if (err != 0)
442 return err;
443
444 err = rtc_valid_range(rtc, &alarm->time);
445 if (err)
446 return err;
447
448 err = mutex_lock_interruptible(&rtc->ops_lock);
449 if (err)
450 return err;
451 if (rtc->aie_timer.enabled)
452 rtc_timer_remove(rtc, &rtc->aie_timer);
453
454 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
455 rtc->aie_timer.period = 0;
456 if (alarm->enabled)
457 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
458
459 mutex_unlock(&rtc->ops_lock);
460
461 return err;
462}
463EXPORT_SYMBOL_GPL(rtc_set_alarm);
464
465/* Called once per device from rtc_device_register */
466int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
467{
468 int err;
469 struct rtc_time now;
470
471 err = rtc_valid_tm(&alarm->time);
472 if (err != 0)
473 return err;
474
475 err = rtc_read_time(rtc, &now);
476 if (err)
477 return err;
478
479 err = mutex_lock_interruptible(&rtc->ops_lock);
480 if (err)
481 return err;
482
483 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
484 rtc->aie_timer.period = 0;
485
486 /* Alarm has to be enabled & in the future for us to enqueue it */
487 if (alarm->enabled && (rtc_tm_to_ktime(now) <
488 rtc->aie_timer.node.expires)) {
489 rtc->aie_timer.enabled = 1;
490 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
491 trace_rtc_timer_enqueue(&rtc->aie_timer);
492 }
493 mutex_unlock(&rtc->ops_lock);
494 return err;
495}
496EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
497
498int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
499{
500 int err;
501
502 err = mutex_lock_interruptible(&rtc->ops_lock);
503 if (err)
504 return err;
505
506 if (rtc->aie_timer.enabled != enabled) {
507 if (enabled)
508 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
509 else
510 rtc_timer_remove(rtc, &rtc->aie_timer);
511 }
512
513 if (err)
514 /* nothing */;
515 else if (!rtc->ops)
516 err = -ENODEV;
517 else if (!rtc->ops->alarm_irq_enable)
518 err = -EINVAL;
519 else
520 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
521
522 mutex_unlock(&rtc->ops_lock);
523
524 trace_rtc_alarm_irq_enable(enabled, err);
525 return err;
526}
527EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
528
529int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
530{
531 int err;
532
533 err = mutex_lock_interruptible(&rtc->ops_lock);
534 if (err)
535 return err;
536
537#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
538 if (enabled == 0 && rtc->uie_irq_active) {
539 mutex_unlock(&rtc->ops_lock);
540 return rtc_dev_update_irq_enable_emul(rtc, 0);
541 }
542#endif
543 /* make sure we're changing state */
544 if (rtc->uie_rtctimer.enabled == enabled)
545 goto out;
546
547 if (rtc->uie_unsupported) {
548 err = -EINVAL;
549 goto out;
550 }
551
552 if (enabled) {
553 struct rtc_time tm;
554 ktime_t now, onesec;
555
556 __rtc_read_time(rtc, &tm);
557 onesec = ktime_set(1, 0);
558 now = rtc_tm_to_ktime(tm);
559 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
560 rtc->uie_rtctimer.period = ktime_set(1, 0);
561 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
562 } else {
563 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
564 }
565
566out:
567 mutex_unlock(&rtc->ops_lock);
568#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
569 /*
570 * Enable emulation if the driver returned -EINVAL to signal that it has
571 * been configured without interrupts or they are not available at the
572 * moment.
573 */
574 if (err == -EINVAL)
575 err = rtc_dev_update_irq_enable_emul(rtc, enabled);
576#endif
577 return err;
578}
579EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
580
581/**
582 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
583 * @rtc: pointer to the rtc device
584 *
585 * This function is called when an AIE, UIE or PIE mode interrupt
586 * has occurred (or been emulated).
587 *
588 */
589void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
590{
591 unsigned long flags;
592
593 /* mark one irq of the appropriate mode */
594 spin_lock_irqsave(&rtc->irq_lock, flags);
595 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF | mode);
596 spin_unlock_irqrestore(&rtc->irq_lock, flags);
597
598 wake_up_interruptible(&rtc->irq_queue);
599 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
600}
601
602/**
603 * rtc_aie_update_irq - AIE mode rtctimer hook
604 * @rtc: pointer to the rtc_device
605 *
606 * This functions is called when the aie_timer expires.
607 */
608void rtc_aie_update_irq(struct rtc_device *rtc)
609{
610 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
611}
612
613/**
614 * rtc_uie_update_irq - UIE mode rtctimer hook
615 * @rtc: pointer to the rtc_device
616 *
617 * This functions is called when the uie_timer expires.
618 */
619void rtc_uie_update_irq(struct rtc_device *rtc)
620{
621 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
622}
623
624/**
625 * rtc_pie_update_irq - PIE mode hrtimer hook
626 * @timer: pointer to the pie mode hrtimer
627 *
628 * This function is used to emulate PIE mode interrupts
629 * using an hrtimer. This function is called when the periodic
630 * hrtimer expires.
631 */
632enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
633{
634 struct rtc_device *rtc;
635 ktime_t period;
636 u64 count;
637
638 rtc = container_of(timer, struct rtc_device, pie_timer);
639
640 period = NSEC_PER_SEC / rtc->irq_freq;
641 count = hrtimer_forward_now(timer, period);
642
643 rtc_handle_legacy_irq(rtc, count, RTC_PF);
644
645 return HRTIMER_RESTART;
646}
647
648/**
649 * rtc_update_irq - Triggered when a RTC interrupt occurs.
650 * @rtc: the rtc device
651 * @num: how many irqs are being reported (usually one)
652 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
653 * Context: any
654 */
655void rtc_update_irq(struct rtc_device *rtc,
656 unsigned long num, unsigned long events)
657{
658 if (IS_ERR_OR_NULL(rtc))
659 return;
660
661 pm_stay_awake(rtc->dev.parent);
662 schedule_work(&rtc->irqwork);
663}
664EXPORT_SYMBOL_GPL(rtc_update_irq);
665
666struct rtc_device *rtc_class_open(const char *name)
667{
668 struct device *dev;
669 struct rtc_device *rtc = NULL;
670
671 dev = class_find_device_by_name(rtc_class, name);
672 if (dev)
673 rtc = to_rtc_device(dev);
674
675 if (rtc) {
676 if (!try_module_get(rtc->owner)) {
677 put_device(dev);
678 rtc = NULL;
679 }
680 }
681
682 return rtc;
683}
684EXPORT_SYMBOL_GPL(rtc_class_open);
685
686void rtc_class_close(struct rtc_device *rtc)
687{
688 module_put(rtc->owner);
689 put_device(&rtc->dev);
690}
691EXPORT_SYMBOL_GPL(rtc_class_close);
692
693static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
694{
695 /*
696 * We always cancel the timer here first, because otherwise
697 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
698 * when we manage to start the timer before the callback
699 * returns HRTIMER_RESTART.
700 *
701 * We cannot use hrtimer_cancel() here as a running callback
702 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
703 * would spin forever.
704 */
705 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
706 return -1;
707
708 if (enabled) {
709 ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
710
711 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
712 }
713 return 0;
714}
715
716/**
717 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
718 * @rtc: the rtc device
719 * @enabled: true to enable periodic IRQs
720 * Context: any
721 *
722 * Note that rtc_irq_set_freq() should previously have been used to
723 * specify the desired frequency of periodic IRQ.
724 */
725int rtc_irq_set_state(struct rtc_device *rtc, int enabled)
726{
727 int err = 0;
728
729 while (rtc_update_hrtimer(rtc, enabled) < 0)
730 cpu_relax();
731
732 rtc->pie_enabled = enabled;
733
734 trace_rtc_irq_set_state(enabled, err);
735 return err;
736}
737
738/**
739 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
740 * @rtc: the rtc device
741 * @freq: positive frequency
742 * Context: any
743 *
744 * Note that rtc_irq_set_state() is used to enable or disable the
745 * periodic IRQs.
746 */
747int rtc_irq_set_freq(struct rtc_device *rtc, int freq)
748{
749 int err = 0;
750
751 if (freq <= 0 || freq > RTC_MAX_FREQ)
752 return -EINVAL;
753
754 rtc->irq_freq = freq;
755 while (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0)
756 cpu_relax();
757
758 trace_rtc_irq_set_freq(freq, err);
759 return err;
760}
761
762/**
763 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
764 * @rtc rtc device
765 * @timer timer being added.
766 *
767 * Enqueues a timer onto the rtc devices timerqueue and sets
768 * the next alarm event appropriately.
769 *
770 * Sets the enabled bit on the added timer.
771 *
772 * Must hold ops_lock for proper serialization of timerqueue
773 */
774static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
775{
776 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
777 struct rtc_time tm;
778 ktime_t now;
779
780 timer->enabled = 1;
781 __rtc_read_time(rtc, &tm);
782 now = rtc_tm_to_ktime(tm);
783
784 /* Skip over expired timers */
785 while (next) {
786 if (next->expires >= now)
787 break;
788 next = timerqueue_iterate_next(next);
789 }
790
791 timerqueue_add(&rtc->timerqueue, &timer->node);
792 trace_rtc_timer_enqueue(timer);
793 if (!next || ktime_before(timer->node.expires, next->expires)) {
794 struct rtc_wkalrm alarm;
795 int err;
796
797 alarm.time = rtc_ktime_to_tm(timer->node.expires);
798 alarm.enabled = 1;
799 err = __rtc_set_alarm(rtc, &alarm);
800 if (err == -ETIME) {
801 pm_stay_awake(rtc->dev.parent);
802 schedule_work(&rtc->irqwork);
803 } else if (err) {
804 timerqueue_del(&rtc->timerqueue, &timer->node);
805 trace_rtc_timer_dequeue(timer);
806 timer->enabled = 0;
807 return err;
808 }
809 }
810 return 0;
811}
812
813static void rtc_alarm_disable(struct rtc_device *rtc)
814{
815 if (!rtc->ops || !rtc->ops->alarm_irq_enable)
816 return;
817
818 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
819 trace_rtc_alarm_irq_enable(0, 0);
820}
821
822/**
823 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
824 * @rtc rtc device
825 * @timer timer being removed.
826 *
827 * Removes a timer onto the rtc devices timerqueue and sets
828 * the next alarm event appropriately.
829 *
830 * Clears the enabled bit on the removed timer.
831 *
832 * Must hold ops_lock for proper serialization of timerqueue
833 */
834static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
835{
836 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
837
838 timerqueue_del(&rtc->timerqueue, &timer->node);
839 trace_rtc_timer_dequeue(timer);
840 timer->enabled = 0;
841 if (next == &timer->node) {
842 struct rtc_wkalrm alarm;
843 int err;
844
845 next = timerqueue_getnext(&rtc->timerqueue);
846 if (!next) {
847 rtc_alarm_disable(rtc);
848 return;
849 }
850 alarm.time = rtc_ktime_to_tm(next->expires);
851 alarm.enabled = 1;
852 err = __rtc_set_alarm(rtc, &alarm);
853 if (err == -ETIME) {
854 pm_stay_awake(rtc->dev.parent);
855 schedule_work(&rtc->irqwork);
856 }
857 }
858}
859
860/**
861 * rtc_timer_do_work - Expires rtc timers
862 * @rtc rtc device
863 * @timer timer being removed.
864 *
865 * Expires rtc timers. Reprograms next alarm event if needed.
866 * Called via worktask.
867 *
868 * Serializes access to timerqueue via ops_lock mutex
869 */
870void rtc_timer_do_work(struct work_struct *work)
871{
872 struct rtc_timer *timer;
873 struct timerqueue_node *next;
874 ktime_t now;
875 struct rtc_time tm;
876
877 struct rtc_device *rtc =
878 container_of(work, struct rtc_device, irqwork);
879
880 mutex_lock(&rtc->ops_lock);
881again:
882 __rtc_read_time(rtc, &tm);
883 now = rtc_tm_to_ktime(tm);
884 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
885 if (next->expires > now)
886 break;
887
888 /* expire timer */
889 timer = container_of(next, struct rtc_timer, node);
890 timerqueue_del(&rtc->timerqueue, &timer->node);
891 trace_rtc_timer_dequeue(timer);
892 timer->enabled = 0;
893 if (timer->func)
894 timer->func(timer->rtc);
895
896 trace_rtc_timer_fired(timer);
897 /* Re-add/fwd periodic timers */
898 if (ktime_to_ns(timer->period)) {
899 timer->node.expires = ktime_add(timer->node.expires,
900 timer->period);
901 timer->enabled = 1;
902 timerqueue_add(&rtc->timerqueue, &timer->node);
903 trace_rtc_timer_enqueue(timer);
904 }
905 }
906
907 /* Set next alarm */
908 if (next) {
909 struct rtc_wkalrm alarm;
910 int err;
911 int retry = 3;
912
913 alarm.time = rtc_ktime_to_tm(next->expires);
914 alarm.enabled = 1;
915reprogram:
916 err = __rtc_set_alarm(rtc, &alarm);
917 if (err == -ETIME) {
918 goto again;
919 } else if (err) {
920 if (retry-- > 0)
921 goto reprogram;
922
923 timer = container_of(next, struct rtc_timer, node);
924 timerqueue_del(&rtc->timerqueue, &timer->node);
925 trace_rtc_timer_dequeue(timer);
926 timer->enabled = 0;
927 dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
928 goto again;
929 }
930 } else {
931 rtc_alarm_disable(rtc);
932 }
933
934 pm_relax(rtc->dev.parent);
935 mutex_unlock(&rtc->ops_lock);
936}
937
938/* rtc_timer_init - Initializes an rtc_timer
939 * @timer: timer to be intiialized
940 * @f: function pointer to be called when timer fires
941 * @rtc: pointer to the rtc_device
942 *
943 * Kernel interface to initializing an rtc_timer.
944 */
945void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
946 struct rtc_device *rtc)
947{
948 timerqueue_init(&timer->node);
949 timer->enabled = 0;
950 timer->func = f;
951 timer->rtc = rtc;
952}
953
954/* rtc_timer_start - Sets an rtc_timer to fire in the future
955 * @ rtc: rtc device to be used
956 * @ timer: timer being set
957 * @ expires: time at which to expire the timer
958 * @ period: period that the timer will recur
959 *
960 * Kernel interface to set an rtc_timer
961 */
962int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
963 ktime_t expires, ktime_t period)
964{
965 int ret = 0;
966
967 mutex_lock(&rtc->ops_lock);
968 if (timer->enabled)
969 rtc_timer_remove(rtc, timer);
970
971 timer->node.expires = expires;
972 timer->period = period;
973
974 ret = rtc_timer_enqueue(rtc, timer);
975
976 mutex_unlock(&rtc->ops_lock);
977 return ret;
978}
979
980/* rtc_timer_cancel - Stops an rtc_timer
981 * @ rtc: rtc device to be used
982 * @ timer: timer being set
983 *
984 * Kernel interface to cancel an rtc_timer
985 */
986void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
987{
988 mutex_lock(&rtc->ops_lock);
989 if (timer->enabled)
990 rtc_timer_remove(rtc, timer);
991 mutex_unlock(&rtc->ops_lock);
992}
993
994/**
995 * rtc_read_offset - Read the amount of rtc offset in parts per billion
996 * @ rtc: rtc device to be used
997 * @ offset: the offset in parts per billion
998 *
999 * see below for details.
1000 *
1001 * Kernel interface to read rtc clock offset
1002 * Returns 0 on success, or a negative number on error.
1003 * If read_offset() is not implemented for the rtc, return -EINVAL
1004 */
1005int rtc_read_offset(struct rtc_device *rtc, long *offset)
1006{
1007 int ret;
1008
1009 if (!rtc->ops)
1010 return -ENODEV;
1011
1012 if (!rtc->ops->read_offset)
1013 return -EINVAL;
1014
1015 mutex_lock(&rtc->ops_lock);
1016 ret = rtc->ops->read_offset(rtc->dev.parent, offset);
1017 mutex_unlock(&rtc->ops_lock);
1018
1019 trace_rtc_read_offset(*offset, ret);
1020 return ret;
1021}
1022
1023/**
1024 * rtc_set_offset - Adjusts the duration of the average second
1025 * @ rtc: rtc device to be used
1026 * @ offset: the offset in parts per billion
1027 *
1028 * Some rtc's allow an adjustment to the average duration of a second
1029 * to compensate for differences in the actual clock rate due to temperature,
1030 * the crystal, capacitor, etc.
1031 *
1032 * The adjustment applied is as follows:
1033 * t = t0 * (1 + offset * 1e-9)
1034 * where t0 is the measured length of 1 RTC second with offset = 0
1035 *
1036 * Kernel interface to adjust an rtc clock offset.
1037 * Return 0 on success, or a negative number on error.
1038 * If the rtc offset is not setable (or not implemented), return -EINVAL
1039 */
1040int rtc_set_offset(struct rtc_device *rtc, long offset)
1041{
1042 int ret;
1043
1044 if (!rtc->ops)
1045 return -ENODEV;
1046
1047 if (!rtc->ops->set_offset)
1048 return -EINVAL;
1049
1050 mutex_lock(&rtc->ops_lock);
1051 ret = rtc->ops->set_offset(rtc->dev.parent, offset);
1052 mutex_unlock(&rtc->ops_lock);
1053
1054 trace_rtc_set_offset(offset, ret);
1055 return ret;
1056}