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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/*
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
20#define CREATE_TRACE_POINTS
21#include <trace/events/rtc.h>
22
23static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
24static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
25
26static void rtc_add_offset(struct rtc_device *rtc, struct rtc_time *tm)
27{
28 time64_t secs;
29
30 if (!rtc->offset_secs)
31 return;
32
33 secs = rtc_tm_to_time64(tm);
34
35 /*
36 * Since the reading time values from RTC device are always in the RTC
37 * original valid range, but we need to skip the overlapped region
38 * between expanded range and original range, which is no need to add
39 * the offset.
40 */
41 if ((rtc->start_secs > rtc->range_min && secs >= rtc->start_secs) ||
42 (rtc->start_secs < rtc->range_min &&
43 secs <= (rtc->start_secs + rtc->range_max - rtc->range_min)))
44 return;
45
46 rtc_time64_to_tm(secs + rtc->offset_secs, tm);
47}
48
49static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm)
50{
51 time64_t secs;
52
53 if (!rtc->offset_secs)
54 return;
55
56 secs = rtc_tm_to_time64(tm);
57
58 /*
59 * If the setting time values are in the valid range of RTC hardware
60 * device, then no need to subtract the offset when setting time to RTC
61 * device. Otherwise we need to subtract the offset to make the time
62 * values are valid for RTC hardware device.
63 */
64 if (secs >= rtc->range_min && secs <= rtc->range_max)
65 return;
66
67 rtc_time64_to_tm(secs - rtc->offset_secs, tm);
68}
69
70static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm)
71{
72 if (rtc->range_min != rtc->range_max) {
73 time64_t time = rtc_tm_to_time64(tm);
74 time64_t range_min = rtc->set_start_time ? rtc->start_secs :
75 rtc->range_min;
76 time64_t range_max = rtc->set_start_time ?
77 (rtc->start_secs + rtc->range_max - rtc->range_min) :
78 rtc->range_max;
79
80 if (time < range_min || time > range_max)
81 return -ERANGE;
82 }
83
84 return 0;
85}
86
87static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
88{
89 int err;
90 if (!rtc->ops)
91 err = -ENODEV;
92 else if (!rtc->ops->read_time)
93 err = -EINVAL;
94 else {
95 memset(tm, 0, sizeof(struct rtc_time));
96 err = rtc->ops->read_time(rtc->dev.parent, tm);
97 if (err < 0) {
98 dev_dbg(&rtc->dev, "read_time: fail to read: %d\n",
99 err);
100 return err;
101 }
102
103 rtc_add_offset(rtc, tm);
104
105 err = rtc_valid_tm(tm);
106 if (err < 0)
107 dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n");
108 }
109 return err;
110}
111
112int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
113{
114 int err;
115
116 err = mutex_lock_interruptible(&rtc->ops_lock);
117 if (err)
118 return err;
119
120 err = __rtc_read_time(rtc, tm);
121 mutex_unlock(&rtc->ops_lock);
122
123 trace_rtc_read_time(rtc_tm_to_time64(tm), err);
124 return err;
125}
126EXPORT_SYMBOL_GPL(rtc_read_time);
127
128int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
129{
130 int err;
131
132 err = rtc_valid_tm(tm);
133 if (err != 0)
134 return err;
135
136 err = rtc_valid_range(rtc, tm);
137 if (err)
138 return err;
139
140 rtc_subtract_offset(rtc, tm);
141
142 err = mutex_lock_interruptible(&rtc->ops_lock);
143 if (err)
144 return err;
145
146 if (!rtc->ops)
147 err = -ENODEV;
148 else if (rtc->ops->set_time)
149 err = rtc->ops->set_time(rtc->dev.parent, tm);
150 else if (rtc->ops->set_mmss64) {
151 time64_t secs64 = rtc_tm_to_time64(tm);
152
153 err = rtc->ops->set_mmss64(rtc->dev.parent, secs64);
154 } else if (rtc->ops->set_mmss) {
155 time64_t secs64 = rtc_tm_to_time64(tm);
156 err = rtc->ops->set_mmss(rtc->dev.parent, secs64);
157 } else
158 err = -EINVAL;
159
160 pm_stay_awake(rtc->dev.parent);
161 mutex_unlock(&rtc->ops_lock);
162 /* A timer might have just expired */
163 schedule_work(&rtc->irqwork);
164
165 trace_rtc_set_time(rtc_tm_to_time64(tm), err);
166 return err;
167}
168EXPORT_SYMBOL_GPL(rtc_set_time);
169
170static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
171{
172 int err;
173
174 err = mutex_lock_interruptible(&rtc->ops_lock);
175 if (err)
176 return err;
177
178 if (rtc->ops == NULL)
179 err = -ENODEV;
180 else if (!rtc->ops->read_alarm)
181 err = -EINVAL;
182 else {
183 alarm->enabled = 0;
184 alarm->pending = 0;
185 alarm->time.tm_sec = -1;
186 alarm->time.tm_min = -1;
187 alarm->time.tm_hour = -1;
188 alarm->time.tm_mday = -1;
189 alarm->time.tm_mon = -1;
190 alarm->time.tm_year = -1;
191 alarm->time.tm_wday = -1;
192 alarm->time.tm_yday = -1;
193 alarm->time.tm_isdst = -1;
194 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
195 }
196
197 mutex_unlock(&rtc->ops_lock);
198
199 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
200 return err;
201}
202
203int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
204{
205 int err;
206 struct rtc_time before, now;
207 int first_time = 1;
208 time64_t t_now, t_alm;
209 enum { none, day, month, year } missing = none;
210 unsigned days;
211
212 /* The lower level RTC driver may return -1 in some fields,
213 * creating invalid alarm->time values, for reasons like:
214 *
215 * - The hardware may not be capable of filling them in;
216 * many alarms match only on time-of-day fields, not
217 * day/month/year calendar data.
218 *
219 * - Some hardware uses illegal values as "wildcard" match
220 * values, which non-Linux firmware (like a BIOS) may try
221 * to set up as e.g. "alarm 15 minutes after each hour".
222 * Linux uses only oneshot alarms.
223 *
224 * When we see that here, we deal with it by using values from
225 * a current RTC timestamp for any missing (-1) values. The
226 * RTC driver prevents "periodic alarm" modes.
227 *
228 * But this can be racey, because some fields of the RTC timestamp
229 * may have wrapped in the interval since we read the RTC alarm,
230 * which would lead to us inserting inconsistent values in place
231 * of the -1 fields.
232 *
233 * Reading the alarm and timestamp in the reverse sequence
234 * would have the same race condition, and not solve the issue.
235 *
236 * So, we must first read the RTC timestamp,
237 * then read the RTC alarm value,
238 * and then read a second RTC timestamp.
239 *
240 * If any fields of the second timestamp have changed
241 * when compared with the first timestamp, then we know
242 * our timestamp may be inconsistent with that used by
243 * the low-level rtc_read_alarm_internal() function.
244 *
245 * So, when the two timestamps disagree, we just loop and do
246 * the process again to get a fully consistent set of values.
247 *
248 * This could all instead be done in the lower level driver,
249 * but since more than one lower level RTC implementation needs it,
250 * then it's probably best best to do it here instead of there..
251 */
252
253 /* Get the "before" timestamp */
254 err = rtc_read_time(rtc, &before);
255 if (err < 0)
256 return err;
257 do {
258 if (!first_time)
259 memcpy(&before, &now, sizeof(struct rtc_time));
260 first_time = 0;
261
262 /* get the RTC alarm values, which may be incomplete */
263 err = rtc_read_alarm_internal(rtc, alarm);
264 if (err)
265 return err;
266
267 /* full-function RTCs won't have such missing fields */
268 if (rtc_valid_tm(&alarm->time) == 0)
269 return 0;
270
271 /* get the "after" timestamp, to detect wrapped fields */
272 err = rtc_read_time(rtc, &now);
273 if (err < 0)
274 return err;
275
276 /* note that tm_sec is a "don't care" value here: */
277 } while ( before.tm_min != now.tm_min
278 || before.tm_hour != now.tm_hour
279 || before.tm_mon != now.tm_mon
280 || before.tm_year != now.tm_year);
281
282 /* Fill in the missing alarm fields using the timestamp; we
283 * know there's at least one since alarm->time is invalid.
284 */
285 if (alarm->time.tm_sec == -1)
286 alarm->time.tm_sec = now.tm_sec;
287 if (alarm->time.tm_min == -1)
288 alarm->time.tm_min = now.tm_min;
289 if (alarm->time.tm_hour == -1)
290 alarm->time.tm_hour = now.tm_hour;
291
292 /* For simplicity, only support date rollover for now */
293 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
294 alarm->time.tm_mday = now.tm_mday;
295 missing = day;
296 }
297 if ((unsigned)alarm->time.tm_mon >= 12) {
298 alarm->time.tm_mon = now.tm_mon;
299 if (missing == none)
300 missing = month;
301 }
302 if (alarm->time.tm_year == -1) {
303 alarm->time.tm_year = now.tm_year;
304 if (missing == none)
305 missing = year;
306 }
307
308 /* Can't proceed if alarm is still invalid after replacing
309 * missing fields.
310 */
311 err = rtc_valid_tm(&alarm->time);
312 if (err)
313 goto done;
314
315 /* with luck, no rollover is needed */
316 t_now = rtc_tm_to_time64(&now);
317 t_alm = rtc_tm_to_time64(&alarm->time);
318 if (t_now < t_alm)
319 goto done;
320
321 switch (missing) {
322
323 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
324 * that will trigger at 5am will do so at 5am Tuesday, which
325 * could also be in the next month or year. This is a common
326 * case, especially for PCs.
327 */
328 case day:
329 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
330 t_alm += 24 * 60 * 60;
331 rtc_time64_to_tm(t_alm, &alarm->time);
332 break;
333
334 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
335 * be next month. An alarm matching on the 30th, 29th, or 28th
336 * may end up in the month after that! Many newer PCs support
337 * this type of alarm.
338 */
339 case month:
340 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
341 do {
342 if (alarm->time.tm_mon < 11)
343 alarm->time.tm_mon++;
344 else {
345 alarm->time.tm_mon = 0;
346 alarm->time.tm_year++;
347 }
348 days = rtc_month_days(alarm->time.tm_mon,
349 alarm->time.tm_year);
350 } while (days < alarm->time.tm_mday);
351 break;
352
353 /* Year rollover ... easy except for leap years! */
354 case year:
355 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
356 do {
357 alarm->time.tm_year++;
358 } while (!is_leap_year(alarm->time.tm_year + 1900)
359 && rtc_valid_tm(&alarm->time) != 0);
360 break;
361
362 default:
363 dev_warn(&rtc->dev, "alarm rollover not handled\n");
364 }
365
366 err = rtc_valid_tm(&alarm->time);
367
368done:
369 if (err) {
370 dev_warn(&rtc->dev, "invalid alarm value: %d-%d-%d %d:%d:%d\n",
371 alarm->time.tm_year + 1900, alarm->time.tm_mon + 1,
372 alarm->time.tm_mday, alarm->time.tm_hour, alarm->time.tm_min,
373 alarm->time.tm_sec);
374 }
375
376 return err;
377}
378
379int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
380{
381 int err;
382
383 err = mutex_lock_interruptible(&rtc->ops_lock);
384 if (err)
385 return err;
386 if (rtc->ops == NULL)
387 err = -ENODEV;
388 else if (!rtc->ops->read_alarm)
389 err = -EINVAL;
390 else {
391 memset(alarm, 0, sizeof(struct rtc_wkalrm));
392 alarm->enabled = rtc->aie_timer.enabled;
393 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
394 }
395 mutex_unlock(&rtc->ops_lock);
396
397 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
398 return err;
399}
400EXPORT_SYMBOL_GPL(rtc_read_alarm);
401
402static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
403{
404 struct rtc_time tm;
405 time64_t now, scheduled;
406 int err;
407
408 err = rtc_valid_tm(&alarm->time);
409 if (err)
410 return err;
411
412 rtc_subtract_offset(rtc, &alarm->time);
413 scheduled = rtc_tm_to_time64(&alarm->time);
414
415 /* Make sure we're not setting alarms in the past */
416 err = __rtc_read_time(rtc, &tm);
417 if (err)
418 return err;
419 now = rtc_tm_to_time64(&tm);
420 if (scheduled <= now)
421 return -ETIME;
422 /*
423 * XXX - We just checked to make sure the alarm time is not
424 * in the past, but there is still a race window where if
425 * the is alarm set for the next second and the second ticks
426 * over right here, before we set the alarm.
427 */
428
429 if (!rtc->ops)
430 err = -ENODEV;
431 else if (!rtc->ops->set_alarm)
432 err = -EINVAL;
433 else
434 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
435
436 trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
437 return err;
438}
439
440int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
441{
442 int err;
443
444 err = rtc_valid_tm(&alarm->time);
445 if (err != 0)
446 return err;
447
448 err = rtc_valid_range(rtc, &alarm->time);
449 if (err)
450 return err;
451
452 err = mutex_lock_interruptible(&rtc->ops_lock);
453 if (err)
454 return err;
455 if (rtc->aie_timer.enabled)
456 rtc_timer_remove(rtc, &rtc->aie_timer);
457
458 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
459 rtc->aie_timer.period = 0;
460 if (alarm->enabled)
461 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
462
463 mutex_unlock(&rtc->ops_lock);
464
465 rtc_add_offset(rtc, &alarm->time);
466 return err;
467}
468EXPORT_SYMBOL_GPL(rtc_set_alarm);
469
470/* Called once per device from rtc_device_register */
471int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
472{
473 int err;
474 struct rtc_time now;
475
476 err = rtc_valid_tm(&alarm->time);
477 if (err != 0)
478 return err;
479
480 err = rtc_read_time(rtc, &now);
481 if (err)
482 return err;
483
484 err = mutex_lock_interruptible(&rtc->ops_lock);
485 if (err)
486 return err;
487
488 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
489 rtc->aie_timer.period = 0;
490
491 /* Alarm has to be enabled & in the future for us to enqueue it */
492 if (alarm->enabled && (rtc_tm_to_ktime(now) <
493 rtc->aie_timer.node.expires)) {
494
495 rtc->aie_timer.enabled = 1;
496 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
497 trace_rtc_timer_enqueue(&rtc->aie_timer);
498 }
499 mutex_unlock(&rtc->ops_lock);
500 return err;
501}
502EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
503
504int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
505{
506 int err = mutex_lock_interruptible(&rtc->ops_lock);
507 if (err)
508 return err;
509
510 if (rtc->aie_timer.enabled != enabled) {
511 if (enabled)
512 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
513 else
514 rtc_timer_remove(rtc, &rtc->aie_timer);
515 }
516
517 if (err)
518 /* nothing */;
519 else if (!rtc->ops)
520 err = -ENODEV;
521 else if (!rtc->ops->alarm_irq_enable)
522 err = -EINVAL;
523 else
524 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
525
526 mutex_unlock(&rtc->ops_lock);
527
528 trace_rtc_alarm_irq_enable(enabled, err);
529 return err;
530}
531EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
532
533int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
534{
535 int err = mutex_lock_interruptible(&rtc->ops_lock);
536 if (err)
537 return err;
538
539#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
540 if (enabled == 0 && rtc->uie_irq_active) {
541 mutex_unlock(&rtc->ops_lock);
542 return rtc_dev_update_irq_enable_emul(rtc, 0);
543 }
544#endif
545 /* make sure we're changing state */
546 if (rtc->uie_rtctimer.enabled == enabled)
547 goto out;
548
549 if (rtc->uie_unsupported) {
550 err = -EINVAL;
551 goto out;
552 }
553
554 if (enabled) {
555 struct rtc_time tm;
556 ktime_t now, onesec;
557
558 __rtc_read_time(rtc, &tm);
559 onesec = ktime_set(1, 0);
560 now = rtc_tm_to_ktime(tm);
561 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
562 rtc->uie_rtctimer.period = ktime_set(1, 0);
563 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
564 } else
565 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
566
567out:
568 mutex_unlock(&rtc->ops_lock);
569#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
570 /*
571 * Enable emulation if the driver did not provide
572 * the update_irq_enable function pointer or if returned
573 * -EINVAL to signal that it has been configured without
574 * interrupts or that are not available at the moment.
575 */
576 if (err == -EINVAL)
577 err = rtc_dev_update_irq_enable_emul(rtc, enabled);
578#endif
579 return err;
580
581}
582EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
583
584
585/**
586 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
587 * @rtc: pointer to the rtc device
588 *
589 * This function is called when an AIE, UIE or PIE mode interrupt
590 * has occurred (or been emulated).
591 *
592 * Triggers the registered irq_task function callback.
593 */
594void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
595{
596 unsigned long flags;
597
598 /* mark one irq of the appropriate mode */
599 spin_lock_irqsave(&rtc->irq_lock, flags);
600 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
601 spin_unlock_irqrestore(&rtc->irq_lock, flags);
602
603 /* call the task func */
604 spin_lock_irqsave(&rtc->irq_task_lock, flags);
605 if (rtc->irq_task)
606 rtc->irq_task->func(rtc->irq_task->private_data);
607 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
608
609 wake_up_interruptible(&rtc->irq_queue);
610 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
611}
612
613
614/**
615 * rtc_aie_update_irq - AIE mode rtctimer hook
616 * @private: pointer to the rtc_device
617 *
618 * This functions is called when the aie_timer expires.
619 */
620void rtc_aie_update_irq(void *private)
621{
622 struct rtc_device *rtc = (struct rtc_device *)private;
623 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
624}
625
626
627/**
628 * rtc_uie_update_irq - UIE mode rtctimer hook
629 * @private: pointer to the rtc_device
630 *
631 * This functions is called when the uie_timer expires.
632 */
633void rtc_uie_update_irq(void *private)
634{
635 struct rtc_device *rtc = (struct rtc_device *)private;
636 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
637}
638
639
640/**
641 * rtc_pie_update_irq - PIE mode hrtimer hook
642 * @timer: pointer to the pie mode hrtimer
643 *
644 * This function is used to emulate PIE mode interrupts
645 * using an hrtimer. This function is called when the periodic
646 * hrtimer expires.
647 */
648enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
649{
650 struct rtc_device *rtc;
651 ktime_t period;
652 int count;
653 rtc = container_of(timer, struct rtc_device, pie_timer);
654
655 period = NSEC_PER_SEC / rtc->irq_freq;
656 count = hrtimer_forward_now(timer, period);
657
658 rtc_handle_legacy_irq(rtc, count, RTC_PF);
659
660 return HRTIMER_RESTART;
661}
662
663/**
664 * rtc_update_irq - Triggered when a RTC interrupt occurs.
665 * @rtc: the rtc device
666 * @num: how many irqs are being reported (usually one)
667 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
668 * Context: any
669 */
670void rtc_update_irq(struct rtc_device *rtc,
671 unsigned long num, unsigned long events)
672{
673 if (IS_ERR_OR_NULL(rtc))
674 return;
675
676 pm_stay_awake(rtc->dev.parent);
677 schedule_work(&rtc->irqwork);
678}
679EXPORT_SYMBOL_GPL(rtc_update_irq);
680
681static int __rtc_match(struct device *dev, const void *data)
682{
683 const char *name = data;
684
685 if (strcmp(dev_name(dev), name) == 0)
686 return 1;
687 return 0;
688}
689
690struct rtc_device *rtc_class_open(const char *name)
691{
692 struct device *dev;
693 struct rtc_device *rtc = NULL;
694
695 dev = class_find_device(rtc_class, NULL, name, __rtc_match);
696 if (dev)
697 rtc = to_rtc_device(dev);
698
699 if (rtc) {
700 if (!try_module_get(rtc->owner)) {
701 put_device(dev);
702 rtc = NULL;
703 }
704 }
705
706 return rtc;
707}
708EXPORT_SYMBOL_GPL(rtc_class_open);
709
710void rtc_class_close(struct rtc_device *rtc)
711{
712 module_put(rtc->owner);
713 put_device(&rtc->dev);
714}
715EXPORT_SYMBOL_GPL(rtc_class_close);
716
717int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
718{
719 int retval = -EBUSY;
720
721 if (task == NULL || task->func == NULL)
722 return -EINVAL;
723
724 /* Cannot register while the char dev is in use */
725 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
726 return -EBUSY;
727
728 spin_lock_irq(&rtc->irq_task_lock);
729 if (rtc->irq_task == NULL) {
730 rtc->irq_task = task;
731 retval = 0;
732 }
733 spin_unlock_irq(&rtc->irq_task_lock);
734
735 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
736
737 return retval;
738}
739EXPORT_SYMBOL_GPL(rtc_irq_register);
740
741void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
742{
743 spin_lock_irq(&rtc->irq_task_lock);
744 if (rtc->irq_task == task)
745 rtc->irq_task = NULL;
746 spin_unlock_irq(&rtc->irq_task_lock);
747}
748EXPORT_SYMBOL_GPL(rtc_irq_unregister);
749
750static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
751{
752 /*
753 * We always cancel the timer here first, because otherwise
754 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
755 * when we manage to start the timer before the callback
756 * returns HRTIMER_RESTART.
757 *
758 * We cannot use hrtimer_cancel() here as a running callback
759 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
760 * would spin forever.
761 */
762 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
763 return -1;
764
765 if (enabled) {
766 ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
767
768 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
769 }
770 return 0;
771}
772
773/**
774 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
775 * @rtc: the rtc device
776 * @task: currently registered with rtc_irq_register()
777 * @enabled: true to enable periodic IRQs
778 * Context: any
779 *
780 * Note that rtc_irq_set_freq() should previously have been used to
781 * specify the desired frequency of periodic IRQ task->func() callbacks.
782 */
783int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
784{
785 int err = 0;
786 unsigned long flags;
787
788retry:
789 spin_lock_irqsave(&rtc->irq_task_lock, flags);
790 if (rtc->irq_task != NULL && task == NULL)
791 err = -EBUSY;
792 else if (rtc->irq_task != task)
793 err = -EACCES;
794 else {
795 if (rtc_update_hrtimer(rtc, enabled) < 0) {
796 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
797 cpu_relax();
798 goto retry;
799 }
800 rtc->pie_enabled = enabled;
801 }
802 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
803
804 trace_rtc_irq_set_state(enabled, err);
805 return err;
806}
807EXPORT_SYMBOL_GPL(rtc_irq_set_state);
808
809/**
810 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
811 * @rtc: the rtc device
812 * @task: currently registered with rtc_irq_register()
813 * @freq: positive frequency with which task->func() will be called
814 * Context: any
815 *
816 * Note that rtc_irq_set_state() is used to enable or disable the
817 * periodic IRQs.
818 */
819int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
820{
821 int err = 0;
822 unsigned long flags;
823
824 if (freq <= 0 || freq > RTC_MAX_FREQ)
825 return -EINVAL;
826retry:
827 spin_lock_irqsave(&rtc->irq_task_lock, flags);
828 if (rtc->irq_task != NULL && task == NULL)
829 err = -EBUSY;
830 else if (rtc->irq_task != task)
831 err = -EACCES;
832 else {
833 rtc->irq_freq = freq;
834 if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) {
835 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
836 cpu_relax();
837 goto retry;
838 }
839 }
840 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
841
842 trace_rtc_irq_set_freq(freq, err);
843 return err;
844}
845EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
846
847/**
848 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
849 * @rtc rtc device
850 * @timer timer being added.
851 *
852 * Enqueues a timer onto the rtc devices timerqueue and sets
853 * the next alarm event appropriately.
854 *
855 * Sets the enabled bit on the added timer.
856 *
857 * Must hold ops_lock for proper serialization of timerqueue
858 */
859static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
860{
861 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
862 struct rtc_time tm;
863 ktime_t now;
864
865 timer->enabled = 1;
866 __rtc_read_time(rtc, &tm);
867 now = rtc_tm_to_ktime(tm);
868
869 /* Skip over expired timers */
870 while (next) {
871 if (next->expires >= now)
872 break;
873 next = timerqueue_iterate_next(next);
874 }
875
876 timerqueue_add(&rtc->timerqueue, &timer->node);
877 trace_rtc_timer_enqueue(timer);
878 if (!next || ktime_before(timer->node.expires, next->expires)) {
879 struct rtc_wkalrm alarm;
880 int err;
881 alarm.time = rtc_ktime_to_tm(timer->node.expires);
882 alarm.enabled = 1;
883 err = __rtc_set_alarm(rtc, &alarm);
884 if (err == -ETIME) {
885 pm_stay_awake(rtc->dev.parent);
886 schedule_work(&rtc->irqwork);
887 } else if (err) {
888 timerqueue_del(&rtc->timerqueue, &timer->node);
889 trace_rtc_timer_dequeue(timer);
890 timer->enabled = 0;
891 return err;
892 }
893 }
894 return 0;
895}
896
897static void rtc_alarm_disable(struct rtc_device *rtc)
898{
899 if (!rtc->ops || !rtc->ops->alarm_irq_enable)
900 return;
901
902 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
903 trace_rtc_alarm_irq_enable(0, 0);
904}
905
906/**
907 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
908 * @rtc rtc device
909 * @timer timer being removed.
910 *
911 * Removes a timer onto the rtc devices timerqueue and sets
912 * the next alarm event appropriately.
913 *
914 * Clears the enabled bit on the removed timer.
915 *
916 * Must hold ops_lock for proper serialization of timerqueue
917 */
918static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
919{
920 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
921 timerqueue_del(&rtc->timerqueue, &timer->node);
922 trace_rtc_timer_dequeue(timer);
923 timer->enabled = 0;
924 if (next == &timer->node) {
925 struct rtc_wkalrm alarm;
926 int err;
927 next = timerqueue_getnext(&rtc->timerqueue);
928 if (!next) {
929 rtc_alarm_disable(rtc);
930 return;
931 }
932 alarm.time = rtc_ktime_to_tm(next->expires);
933 alarm.enabled = 1;
934 err = __rtc_set_alarm(rtc, &alarm);
935 if (err == -ETIME) {
936 pm_stay_awake(rtc->dev.parent);
937 schedule_work(&rtc->irqwork);
938 }
939 }
940}
941
942/**
943 * rtc_timer_do_work - Expires rtc timers
944 * @rtc rtc device
945 * @timer timer being removed.
946 *
947 * Expires rtc timers. Reprograms next alarm event if needed.
948 * Called via worktask.
949 *
950 * Serializes access to timerqueue via ops_lock mutex
951 */
952void rtc_timer_do_work(struct work_struct *work)
953{
954 struct rtc_timer *timer;
955 struct timerqueue_node *next;
956 ktime_t now;
957 struct rtc_time tm;
958
959 struct rtc_device *rtc =
960 container_of(work, struct rtc_device, irqwork);
961
962 mutex_lock(&rtc->ops_lock);
963again:
964 __rtc_read_time(rtc, &tm);
965 now = rtc_tm_to_ktime(tm);
966 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
967 if (next->expires > now)
968 break;
969
970 /* expire timer */
971 timer = container_of(next, struct rtc_timer, node);
972 timerqueue_del(&rtc->timerqueue, &timer->node);
973 trace_rtc_timer_dequeue(timer);
974 timer->enabled = 0;
975 if (timer->task.func)
976 timer->task.func(timer->task.private_data);
977
978 trace_rtc_timer_fired(timer);
979 /* Re-add/fwd periodic timers */
980 if (ktime_to_ns(timer->period)) {
981 timer->node.expires = ktime_add(timer->node.expires,
982 timer->period);
983 timer->enabled = 1;
984 timerqueue_add(&rtc->timerqueue, &timer->node);
985 trace_rtc_timer_enqueue(timer);
986 }
987 }
988
989 /* Set next alarm */
990 if (next) {
991 struct rtc_wkalrm alarm;
992 int err;
993 int retry = 3;
994
995 alarm.time = rtc_ktime_to_tm(next->expires);
996 alarm.enabled = 1;
997reprogram:
998 err = __rtc_set_alarm(rtc, &alarm);
999 if (err == -ETIME)
1000 goto again;
1001 else if (err) {
1002 if (retry-- > 0)
1003 goto reprogram;
1004
1005 timer = container_of(next, struct rtc_timer, node);
1006 timerqueue_del(&rtc->timerqueue, &timer->node);
1007 trace_rtc_timer_dequeue(timer);
1008 timer->enabled = 0;
1009 dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
1010 goto again;
1011 }
1012 } else
1013 rtc_alarm_disable(rtc);
1014
1015 pm_relax(rtc->dev.parent);
1016 mutex_unlock(&rtc->ops_lock);
1017}
1018
1019
1020/* rtc_timer_init - Initializes an rtc_timer
1021 * @timer: timer to be intiialized
1022 * @f: function pointer to be called when timer fires
1023 * @data: private data passed to function pointer
1024 *
1025 * Kernel interface to initializing an rtc_timer.
1026 */
1027void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data)
1028{
1029 timerqueue_init(&timer->node);
1030 timer->enabled = 0;
1031 timer->task.func = f;
1032 timer->task.private_data = data;
1033}
1034
1035/* rtc_timer_start - Sets an rtc_timer to fire in the future
1036 * @ rtc: rtc device to be used
1037 * @ timer: timer being set
1038 * @ expires: time at which to expire the timer
1039 * @ period: period that the timer will recur
1040 *
1041 * Kernel interface to set an rtc_timer
1042 */
1043int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
1044 ktime_t expires, ktime_t period)
1045{
1046 int ret = 0;
1047 mutex_lock(&rtc->ops_lock);
1048 if (timer->enabled)
1049 rtc_timer_remove(rtc, timer);
1050
1051 timer->node.expires = expires;
1052 timer->period = period;
1053
1054 ret = rtc_timer_enqueue(rtc, timer);
1055
1056 mutex_unlock(&rtc->ops_lock);
1057 return ret;
1058}
1059
1060/* rtc_timer_cancel - Stops an rtc_timer
1061 * @ rtc: rtc device to be used
1062 * @ timer: timer being set
1063 *
1064 * Kernel interface to cancel an rtc_timer
1065 */
1066void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
1067{
1068 mutex_lock(&rtc->ops_lock);
1069 if (timer->enabled)
1070 rtc_timer_remove(rtc, timer);
1071 mutex_unlock(&rtc->ops_lock);
1072}
1073
1074/**
1075 * rtc_read_offset - Read the amount of rtc offset in parts per billion
1076 * @ rtc: rtc device to be used
1077 * @ offset: the offset in parts per billion
1078 *
1079 * see below for details.
1080 *
1081 * Kernel interface to read rtc clock offset
1082 * Returns 0 on success, or a negative number on error.
1083 * If read_offset() is not implemented for the rtc, return -EINVAL
1084 */
1085int rtc_read_offset(struct rtc_device *rtc, long *offset)
1086{
1087 int ret;
1088
1089 if (!rtc->ops)
1090 return -ENODEV;
1091
1092 if (!rtc->ops->read_offset)
1093 return -EINVAL;
1094
1095 mutex_lock(&rtc->ops_lock);
1096 ret = rtc->ops->read_offset(rtc->dev.parent, offset);
1097 mutex_unlock(&rtc->ops_lock);
1098
1099 trace_rtc_read_offset(*offset, ret);
1100 return ret;
1101}
1102
1103/**
1104 * rtc_set_offset - Adjusts the duration of the average second
1105 * @ rtc: rtc device to be used
1106 * @ offset: the offset in parts per billion
1107 *
1108 * Some rtc's allow an adjustment to the average duration of a second
1109 * to compensate for differences in the actual clock rate due to temperature,
1110 * the crystal, capacitor, etc.
1111 *
1112 * The adjustment applied is as follows:
1113 * t = t0 * (1 + offset * 1e-9)
1114 * where t0 is the measured length of 1 RTC second with offset = 0
1115 *
1116 * Kernel interface to adjust an rtc clock offset.
1117 * Return 0 on success, or a negative number on error.
1118 * If the rtc offset is not setable (or not implemented), return -EINVAL
1119 */
1120int rtc_set_offset(struct rtc_device *rtc, long offset)
1121{
1122 int ret;
1123
1124 if (!rtc->ops)
1125 return -ENODEV;
1126
1127 if (!rtc->ops->set_offset)
1128 return -EINVAL;
1129
1130 mutex_lock(&rtc->ops_lock);
1131 ret = rtc->ops->set_offset(rtc->dev.parent, offset);
1132 mutex_unlock(&rtc->ops_lock);
1133
1134 trace_rtc_set_offset(offset, ret);
1135 return ret;
1136}