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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 timeu64_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, uie;
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#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
141 uie = rtc->uie_rtctimer.enabled || rtc->uie_irq_active;
142#else
143 uie = rtc->uie_rtctimer.enabled;
144#endif
145 if (uie) {
146 err = rtc_update_irq_enable(rtc, 0);
147 if (err)
148 return err;
149 }
150
151 err = mutex_lock_interruptible(&rtc->ops_lock);
152 if (err)
153 return err;
154
155 if (!rtc->ops)
156 err = -ENODEV;
157 else if (rtc->ops->set_time)
158 err = rtc->ops->set_time(rtc->dev.parent, tm);
159 else
160 err = -EINVAL;
161
162 pm_stay_awake(rtc->dev.parent);
163 mutex_unlock(&rtc->ops_lock);
164 /* A timer might have just expired */
165 schedule_work(&rtc->irqwork);
166
167 if (uie) {
168 err = rtc_update_irq_enable(rtc, 1);
169 if (err)
170 return err;
171 }
172
173 trace_rtc_set_time(rtc_tm_to_time64(tm), err);
174 return err;
175}
176EXPORT_SYMBOL_GPL(rtc_set_time);
177
178static int rtc_read_alarm_internal(struct rtc_device *rtc,
179 struct rtc_wkalrm *alarm)
180{
181 int err;
182
183 err = mutex_lock_interruptible(&rtc->ops_lock);
184 if (err)
185 return err;
186
187 if (!rtc->ops) {
188 err = -ENODEV;
189 } else if (!rtc->ops->read_alarm) {
190 err = -EINVAL;
191 } else {
192 alarm->enabled = 0;
193 alarm->pending = 0;
194 alarm->time.tm_sec = -1;
195 alarm->time.tm_min = -1;
196 alarm->time.tm_hour = -1;
197 alarm->time.tm_mday = -1;
198 alarm->time.tm_mon = -1;
199 alarm->time.tm_year = -1;
200 alarm->time.tm_wday = -1;
201 alarm->time.tm_yday = -1;
202 alarm->time.tm_isdst = -1;
203 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
204 }
205
206 mutex_unlock(&rtc->ops_lock);
207
208 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
209 return err;
210}
211
212int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
213{
214 int err;
215 struct rtc_time before, now;
216 int first_time = 1;
217 time64_t t_now, t_alm;
218 enum { none, day, month, year } missing = none;
219 unsigned int days;
220
221 /* The lower level RTC driver may return -1 in some fields,
222 * creating invalid alarm->time values, for reasons like:
223 *
224 * - The hardware may not be capable of filling them in;
225 * many alarms match only on time-of-day fields, not
226 * day/month/year calendar data.
227 *
228 * - Some hardware uses illegal values as "wildcard" match
229 * values, which non-Linux firmware (like a BIOS) may try
230 * to set up as e.g. "alarm 15 minutes after each hour".
231 * Linux uses only oneshot alarms.
232 *
233 * When we see that here, we deal with it by using values from
234 * a current RTC timestamp for any missing (-1) values. The
235 * RTC driver prevents "periodic alarm" modes.
236 *
237 * But this can be racey, because some fields of the RTC timestamp
238 * may have wrapped in the interval since we read the RTC alarm,
239 * which would lead to us inserting inconsistent values in place
240 * of the -1 fields.
241 *
242 * Reading the alarm and timestamp in the reverse sequence
243 * would have the same race condition, and not solve the issue.
244 *
245 * So, we must first read the RTC timestamp,
246 * then read the RTC alarm value,
247 * and then read a second RTC timestamp.
248 *
249 * If any fields of the second timestamp have changed
250 * when compared with the first timestamp, then we know
251 * our timestamp may be inconsistent with that used by
252 * the low-level rtc_read_alarm_internal() function.
253 *
254 * So, when the two timestamps disagree, we just loop and do
255 * the process again to get a fully consistent set of values.
256 *
257 * This could all instead be done in the lower level driver,
258 * but since more than one lower level RTC implementation needs it,
259 * then it's probably best best to do it here instead of there..
260 */
261
262 /* Get the "before" timestamp */
263 err = rtc_read_time(rtc, &before);
264 if (err < 0)
265 return err;
266 do {
267 if (!first_time)
268 memcpy(&before, &now, sizeof(struct rtc_time));
269 first_time = 0;
270
271 /* get the RTC alarm values, which may be incomplete */
272 err = rtc_read_alarm_internal(rtc, alarm);
273 if (err)
274 return err;
275
276 /* full-function RTCs won't have such missing fields */
277 if (rtc_valid_tm(&alarm->time) == 0) {
278 rtc_add_offset(rtc, &alarm->time);
279 return 0;
280 }
281
282 /* get the "after" timestamp, to detect wrapped fields */
283 err = rtc_read_time(rtc, &now);
284 if (err < 0)
285 return err;
286
287 /* note that tm_sec is a "don't care" value here: */
288 } while (before.tm_min != now.tm_min ||
289 before.tm_hour != now.tm_hour ||
290 before.tm_mon != now.tm_mon ||
291 before.tm_year != now.tm_year);
292
293 /* Fill in the missing alarm fields using the timestamp; we
294 * know there's at least one since alarm->time is invalid.
295 */
296 if (alarm->time.tm_sec == -1)
297 alarm->time.tm_sec = now.tm_sec;
298 if (alarm->time.tm_min == -1)
299 alarm->time.tm_min = now.tm_min;
300 if (alarm->time.tm_hour == -1)
301 alarm->time.tm_hour = now.tm_hour;
302
303 /* For simplicity, only support date rollover for now */
304 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
305 alarm->time.tm_mday = now.tm_mday;
306 missing = day;
307 }
308 if ((unsigned int)alarm->time.tm_mon >= 12) {
309 alarm->time.tm_mon = now.tm_mon;
310 if (missing == none)
311 missing = month;
312 }
313 if (alarm->time.tm_year == -1) {
314 alarm->time.tm_year = now.tm_year;
315 if (missing == none)
316 missing = year;
317 }
318
319 /* Can't proceed if alarm is still invalid after replacing
320 * missing fields.
321 */
322 err = rtc_valid_tm(&alarm->time);
323 if (err)
324 goto done;
325
326 /* with luck, no rollover is needed */
327 t_now = rtc_tm_to_time64(&now);
328 t_alm = rtc_tm_to_time64(&alarm->time);
329 if (t_now < t_alm)
330 goto done;
331
332 switch (missing) {
333 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
334 * that will trigger at 5am will do so at 5am Tuesday, which
335 * could also be in the next month or year. This is a common
336 * case, especially for PCs.
337 */
338 case day:
339 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
340 t_alm += 24 * 60 * 60;
341 rtc_time64_to_tm(t_alm, &alarm->time);
342 break;
343
344 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
345 * be next month. An alarm matching on the 30th, 29th, or 28th
346 * may end up in the month after that! Many newer PCs support
347 * this type of alarm.
348 */
349 case month:
350 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
351 do {
352 if (alarm->time.tm_mon < 11) {
353 alarm->time.tm_mon++;
354 } else {
355 alarm->time.tm_mon = 0;
356 alarm->time.tm_year++;
357 }
358 days = rtc_month_days(alarm->time.tm_mon,
359 alarm->time.tm_year);
360 } while (days < alarm->time.tm_mday);
361 break;
362
363 /* Year rollover ... easy except for leap years! */
364 case year:
365 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
366 do {
367 alarm->time.tm_year++;
368 } while (!is_leap_year(alarm->time.tm_year + 1900) &&
369 rtc_valid_tm(&alarm->time) != 0);
370 break;
371
372 default:
373 dev_warn(&rtc->dev, "alarm rollover not handled\n");
374 }
375
376 err = rtc_valid_tm(&alarm->time);
377
378done:
379 if (err)
380 dev_warn(&rtc->dev, "invalid alarm value: %ptR\n",
381 &alarm->time);
382
383 return err;
384}
385
386int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
387{
388 int err;
389
390 err = mutex_lock_interruptible(&rtc->ops_lock);
391 if (err)
392 return err;
393 if (!rtc->ops) {
394 err = -ENODEV;
395 } else if (!rtc->ops->read_alarm) {
396 err = -EINVAL;
397 } else {
398 memset(alarm, 0, sizeof(struct rtc_wkalrm));
399 alarm->enabled = rtc->aie_timer.enabled;
400 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
401 }
402 mutex_unlock(&rtc->ops_lock);
403
404 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
405 return err;
406}
407EXPORT_SYMBOL_GPL(rtc_read_alarm);
408
409static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
410{
411 struct rtc_time tm;
412 time64_t now, scheduled;
413 int err;
414
415 err = rtc_valid_tm(&alarm->time);
416 if (err)
417 return err;
418
419 scheduled = rtc_tm_to_time64(&alarm->time);
420
421 /* Make sure we're not setting alarms in the past */
422 err = __rtc_read_time(rtc, &tm);
423 if (err)
424 return err;
425 now = rtc_tm_to_time64(&tm);
426 if (scheduled <= now)
427 return -ETIME;
428 /*
429 * XXX - We just checked to make sure the alarm time is not
430 * in the past, but there is still a race window where if
431 * the is alarm set for the next second and the second ticks
432 * over right here, before we set the alarm.
433 */
434
435 rtc_subtract_offset(rtc, &alarm->time);
436
437 if (!rtc->ops)
438 err = -ENODEV;
439 else if (!rtc->ops->set_alarm)
440 err = -EINVAL;
441 else
442 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
443
444 trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
445 return err;
446}
447
448int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
449{
450 int err;
451
452 if (!rtc->ops)
453 return -ENODEV;
454 else if (!rtc->ops->set_alarm)
455 return -EINVAL;
456
457 err = rtc_valid_tm(&alarm->time);
458 if (err != 0)
459 return err;
460
461 err = rtc_valid_range(rtc, &alarm->time);
462 if (err)
463 return err;
464
465 err = mutex_lock_interruptible(&rtc->ops_lock);
466 if (err)
467 return err;
468 if (rtc->aie_timer.enabled)
469 rtc_timer_remove(rtc, &rtc->aie_timer);
470
471 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
472 rtc->aie_timer.period = 0;
473 if (alarm->enabled)
474 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
475
476 mutex_unlock(&rtc->ops_lock);
477
478 return err;
479}
480EXPORT_SYMBOL_GPL(rtc_set_alarm);
481
482/* Called once per device from rtc_device_register */
483int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
484{
485 int err;
486 struct rtc_time now;
487
488 err = rtc_valid_tm(&alarm->time);
489 if (err != 0)
490 return err;
491
492 err = rtc_read_time(rtc, &now);
493 if (err)
494 return err;
495
496 err = mutex_lock_interruptible(&rtc->ops_lock);
497 if (err)
498 return err;
499
500 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
501 rtc->aie_timer.period = 0;
502
503 /* Alarm has to be enabled & in the future for us to enqueue it */
504 if (alarm->enabled && (rtc_tm_to_ktime(now) <
505 rtc->aie_timer.node.expires)) {
506 rtc->aie_timer.enabled = 1;
507 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
508 trace_rtc_timer_enqueue(&rtc->aie_timer);
509 }
510 mutex_unlock(&rtc->ops_lock);
511 return err;
512}
513EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
514
515int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
516{
517 int err;
518
519 err = mutex_lock_interruptible(&rtc->ops_lock);
520 if (err)
521 return err;
522
523 if (rtc->aie_timer.enabled != enabled) {
524 if (enabled)
525 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
526 else
527 rtc_timer_remove(rtc, &rtc->aie_timer);
528 }
529
530 if (err)
531 /* nothing */;
532 else if (!rtc->ops)
533 err = -ENODEV;
534 else if (!rtc->ops->alarm_irq_enable)
535 err = -EINVAL;
536 else
537 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
538
539 mutex_unlock(&rtc->ops_lock);
540
541 trace_rtc_alarm_irq_enable(enabled, err);
542 return err;
543}
544EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
545
546int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
547{
548 int rc = 0, err;
549
550 err = mutex_lock_interruptible(&rtc->ops_lock);
551 if (err)
552 return err;
553
554#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
555 if (enabled == 0 && rtc->uie_irq_active) {
556 mutex_unlock(&rtc->ops_lock);
557 return rtc_dev_update_irq_enable_emul(rtc, 0);
558 }
559#endif
560 /* make sure we're changing state */
561 if (rtc->uie_rtctimer.enabled == enabled)
562 goto out;
563
564 if (rtc->uie_unsupported) {
565 err = -EINVAL;
566 goto out;
567 }
568
569 if (enabled) {
570 struct rtc_time tm;
571 ktime_t now, onesec;
572
573 rc = __rtc_read_time(rtc, &tm);
574 if (rc)
575 goto out;
576 onesec = ktime_set(1, 0);
577 now = rtc_tm_to_ktime(tm);
578 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
579 rtc->uie_rtctimer.period = ktime_set(1, 0);
580 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
581 } else {
582 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
583 }
584
585out:
586 mutex_unlock(&rtc->ops_lock);
587
588 /*
589 * __rtc_read_time() failed, this probably means that the RTC time has
590 * never been set or less probably there is a transient error on the
591 * bus. In any case, avoid enabling emulation has this will fail when
592 * reading the time too.
593 */
594 if (rc)
595 return rc;
596
597#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
598 /*
599 * Enable emulation if the driver returned -EINVAL to signal that it has
600 * been configured without interrupts or they are not available at the
601 * moment.
602 */
603 if (err == -EINVAL)
604 err = rtc_dev_update_irq_enable_emul(rtc, enabled);
605#endif
606 return err;
607}
608EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
609
610/**
611 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
612 * @rtc: pointer to the rtc device
613 * @num: number of occurence of the event
614 * @mode: type of the event, RTC_AF, RTC_UF of RTC_PF
615 *
616 * This function is called when an AIE, UIE or PIE mode interrupt
617 * has occurred (or been emulated).
618 *
619 */
620void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
621{
622 unsigned long flags;
623
624 /* mark one irq of the appropriate mode */
625 spin_lock_irqsave(&rtc->irq_lock, flags);
626 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF | mode);
627 spin_unlock_irqrestore(&rtc->irq_lock, flags);
628
629 wake_up_interruptible(&rtc->irq_queue);
630 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
631}
632
633/**
634 * rtc_aie_update_irq - AIE mode rtctimer hook
635 * @rtc: pointer to the rtc_device
636 *
637 * This functions is called when the aie_timer expires.
638 */
639void rtc_aie_update_irq(struct rtc_device *rtc)
640{
641 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
642}
643
644/**
645 * rtc_uie_update_irq - UIE mode rtctimer hook
646 * @rtc: pointer to the rtc_device
647 *
648 * This functions is called when the uie_timer expires.
649 */
650void rtc_uie_update_irq(struct rtc_device *rtc)
651{
652 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
653}
654
655/**
656 * rtc_pie_update_irq - PIE mode hrtimer hook
657 * @timer: pointer to the pie mode hrtimer
658 *
659 * This function is used to emulate PIE mode interrupts
660 * using an hrtimer. This function is called when the periodic
661 * hrtimer expires.
662 */
663enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
664{
665 struct rtc_device *rtc;
666 ktime_t period;
667 u64 count;
668
669 rtc = container_of(timer, struct rtc_device, pie_timer);
670
671 period = NSEC_PER_SEC / rtc->irq_freq;
672 count = hrtimer_forward_now(timer, period);
673
674 rtc_handle_legacy_irq(rtc, count, RTC_PF);
675
676 return HRTIMER_RESTART;
677}
678
679/**
680 * rtc_update_irq - Triggered when a RTC interrupt occurs.
681 * @rtc: the rtc device
682 * @num: how many irqs are being reported (usually one)
683 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
684 * Context: any
685 */
686void rtc_update_irq(struct rtc_device *rtc,
687 unsigned long num, unsigned long events)
688{
689 if (IS_ERR_OR_NULL(rtc))
690 return;
691
692 pm_stay_awake(rtc->dev.parent);
693 schedule_work(&rtc->irqwork);
694}
695EXPORT_SYMBOL_GPL(rtc_update_irq);
696
697struct rtc_device *rtc_class_open(const char *name)
698{
699 struct device *dev;
700 struct rtc_device *rtc = NULL;
701
702 dev = class_find_device_by_name(rtc_class, name);
703 if (dev)
704 rtc = to_rtc_device(dev);
705
706 if (rtc) {
707 if (!try_module_get(rtc->owner)) {
708 put_device(dev);
709 rtc = NULL;
710 }
711 }
712
713 return rtc;
714}
715EXPORT_SYMBOL_GPL(rtc_class_open);
716
717void rtc_class_close(struct rtc_device *rtc)
718{
719 module_put(rtc->owner);
720 put_device(&rtc->dev);
721}
722EXPORT_SYMBOL_GPL(rtc_class_close);
723
724static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
725{
726 /*
727 * We always cancel the timer here first, because otherwise
728 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
729 * when we manage to start the timer before the callback
730 * returns HRTIMER_RESTART.
731 *
732 * We cannot use hrtimer_cancel() here as a running callback
733 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
734 * would spin forever.
735 */
736 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
737 return -1;
738
739 if (enabled) {
740 ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
741
742 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
743 }
744 return 0;
745}
746
747/**
748 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
749 * @rtc: the rtc device
750 * @enabled: true to enable periodic IRQs
751 * Context: any
752 *
753 * Note that rtc_irq_set_freq() should previously have been used to
754 * specify the desired frequency of periodic IRQ.
755 */
756int rtc_irq_set_state(struct rtc_device *rtc, int enabled)
757{
758 int err = 0;
759
760 while (rtc_update_hrtimer(rtc, enabled) < 0)
761 cpu_relax();
762
763 rtc->pie_enabled = enabled;
764
765 trace_rtc_irq_set_state(enabled, err);
766 return err;
767}
768
769/**
770 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
771 * @rtc: the rtc device
772 * @freq: positive frequency
773 * Context: any
774 *
775 * Note that rtc_irq_set_state() is used to enable or disable the
776 * periodic IRQs.
777 */
778int rtc_irq_set_freq(struct rtc_device *rtc, int freq)
779{
780 int err = 0;
781
782 if (freq <= 0 || freq > RTC_MAX_FREQ)
783 return -EINVAL;
784
785 rtc->irq_freq = freq;
786 while (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0)
787 cpu_relax();
788
789 trace_rtc_irq_set_freq(freq, err);
790 return err;
791}
792
793/**
794 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
795 * @rtc: rtc device
796 * @timer: timer being added.
797 *
798 * Enqueues a timer onto the rtc devices timerqueue and sets
799 * the next alarm event appropriately.
800 *
801 * Sets the enabled bit on the added timer.
802 *
803 * Must hold ops_lock for proper serialization of timerqueue
804 */
805static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
806{
807 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
808 struct rtc_time tm;
809 ktime_t now;
810
811 timer->enabled = 1;
812 __rtc_read_time(rtc, &tm);
813 now = rtc_tm_to_ktime(tm);
814
815 /* Skip over expired timers */
816 while (next) {
817 if (next->expires >= now)
818 break;
819 next = timerqueue_iterate_next(next);
820 }
821
822 timerqueue_add(&rtc->timerqueue, &timer->node);
823 trace_rtc_timer_enqueue(timer);
824 if (!next || ktime_before(timer->node.expires, next->expires)) {
825 struct rtc_wkalrm alarm;
826 int err;
827
828 alarm.time = rtc_ktime_to_tm(timer->node.expires);
829 alarm.enabled = 1;
830 err = __rtc_set_alarm(rtc, &alarm);
831 if (err == -ETIME) {
832 pm_stay_awake(rtc->dev.parent);
833 schedule_work(&rtc->irqwork);
834 } else if (err) {
835 timerqueue_del(&rtc->timerqueue, &timer->node);
836 trace_rtc_timer_dequeue(timer);
837 timer->enabled = 0;
838 return err;
839 }
840 }
841 return 0;
842}
843
844static void rtc_alarm_disable(struct rtc_device *rtc)
845{
846 if (!rtc->ops || !rtc->ops->alarm_irq_enable)
847 return;
848
849 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
850 trace_rtc_alarm_irq_enable(0, 0);
851}
852
853/**
854 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
855 * @rtc: rtc device
856 * @timer: timer being removed.
857 *
858 * Removes a timer onto the rtc devices timerqueue and sets
859 * the next alarm event appropriately.
860 *
861 * Clears the enabled bit on the removed timer.
862 *
863 * Must hold ops_lock for proper serialization of timerqueue
864 */
865static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
866{
867 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
868
869 timerqueue_del(&rtc->timerqueue, &timer->node);
870 trace_rtc_timer_dequeue(timer);
871 timer->enabled = 0;
872 if (next == &timer->node) {
873 struct rtc_wkalrm alarm;
874 int err;
875
876 next = timerqueue_getnext(&rtc->timerqueue);
877 if (!next) {
878 rtc_alarm_disable(rtc);
879 return;
880 }
881 alarm.time = rtc_ktime_to_tm(next->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 }
888 }
889}
890
891/**
892 * rtc_timer_do_work - Expires rtc timers
893 * @work: work item
894 *
895 * Expires rtc timers. Reprograms next alarm event if needed.
896 * Called via worktask.
897 *
898 * Serializes access to timerqueue via ops_lock mutex
899 */
900void rtc_timer_do_work(struct work_struct *work)
901{
902 struct rtc_timer *timer;
903 struct timerqueue_node *next;
904 ktime_t now;
905 struct rtc_time tm;
906
907 struct rtc_device *rtc =
908 container_of(work, struct rtc_device, irqwork);
909
910 mutex_lock(&rtc->ops_lock);
911again:
912 __rtc_read_time(rtc, &tm);
913 now = rtc_tm_to_ktime(tm);
914 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
915 if (next->expires > now)
916 break;
917
918 /* expire timer */
919 timer = container_of(next, struct rtc_timer, node);
920 timerqueue_del(&rtc->timerqueue, &timer->node);
921 trace_rtc_timer_dequeue(timer);
922 timer->enabled = 0;
923 if (timer->func)
924 timer->func(timer->rtc);
925
926 trace_rtc_timer_fired(timer);
927 /* Re-add/fwd periodic timers */
928 if (ktime_to_ns(timer->period)) {
929 timer->node.expires = ktime_add(timer->node.expires,
930 timer->period);
931 timer->enabled = 1;
932 timerqueue_add(&rtc->timerqueue, &timer->node);
933 trace_rtc_timer_enqueue(timer);
934 }
935 }
936
937 /* Set next alarm */
938 if (next) {
939 struct rtc_wkalrm alarm;
940 int err;
941 int retry = 3;
942
943 alarm.time = rtc_ktime_to_tm(next->expires);
944 alarm.enabled = 1;
945reprogram:
946 err = __rtc_set_alarm(rtc, &alarm);
947 if (err == -ETIME) {
948 goto again;
949 } else if (err) {
950 if (retry-- > 0)
951 goto reprogram;
952
953 timer = container_of(next, struct rtc_timer, node);
954 timerqueue_del(&rtc->timerqueue, &timer->node);
955 trace_rtc_timer_dequeue(timer);
956 timer->enabled = 0;
957 dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
958 goto again;
959 }
960 } else {
961 rtc_alarm_disable(rtc);
962 }
963
964 pm_relax(rtc->dev.parent);
965 mutex_unlock(&rtc->ops_lock);
966}
967
968/* rtc_timer_init - Initializes an rtc_timer
969 * @timer: timer to be intiialized
970 * @f: function pointer to be called when timer fires
971 * @rtc: pointer to the rtc_device
972 *
973 * Kernel interface to initializing an rtc_timer.
974 */
975void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
976 struct rtc_device *rtc)
977{
978 timerqueue_init(&timer->node);
979 timer->enabled = 0;
980 timer->func = f;
981 timer->rtc = rtc;
982}
983
984/* rtc_timer_start - Sets an rtc_timer to fire in the future
985 * @ rtc: rtc device to be used
986 * @ timer: timer being set
987 * @ expires: time at which to expire the timer
988 * @ period: period that the timer will recur
989 *
990 * Kernel interface to set an rtc_timer
991 */
992int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
993 ktime_t expires, ktime_t period)
994{
995 int ret = 0;
996
997 mutex_lock(&rtc->ops_lock);
998 if (timer->enabled)
999 rtc_timer_remove(rtc, timer);
1000
1001 timer->node.expires = expires;
1002 timer->period = period;
1003
1004 ret = rtc_timer_enqueue(rtc, timer);
1005
1006 mutex_unlock(&rtc->ops_lock);
1007 return ret;
1008}
1009
1010/* rtc_timer_cancel - Stops an rtc_timer
1011 * @ rtc: rtc device to be used
1012 * @ timer: timer being set
1013 *
1014 * Kernel interface to cancel an rtc_timer
1015 */
1016void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
1017{
1018 mutex_lock(&rtc->ops_lock);
1019 if (timer->enabled)
1020 rtc_timer_remove(rtc, timer);
1021 mutex_unlock(&rtc->ops_lock);
1022}
1023
1024/**
1025 * rtc_read_offset - Read the amount of rtc offset in parts per billion
1026 * @rtc: rtc device to be used
1027 * @offset: the offset in parts per billion
1028 *
1029 * see below for details.
1030 *
1031 * Kernel interface to read rtc clock offset
1032 * Returns 0 on success, or a negative number on error.
1033 * If read_offset() is not implemented for the rtc, return -EINVAL
1034 */
1035int rtc_read_offset(struct rtc_device *rtc, long *offset)
1036{
1037 int ret;
1038
1039 if (!rtc->ops)
1040 return -ENODEV;
1041
1042 if (!rtc->ops->read_offset)
1043 return -EINVAL;
1044
1045 mutex_lock(&rtc->ops_lock);
1046 ret = rtc->ops->read_offset(rtc->dev.parent, offset);
1047 mutex_unlock(&rtc->ops_lock);
1048
1049 trace_rtc_read_offset(*offset, ret);
1050 return ret;
1051}
1052
1053/**
1054 * rtc_set_offset - Adjusts the duration of the average second
1055 * @rtc: rtc device to be used
1056 * @offset: the offset in parts per billion
1057 *
1058 * Some rtc's allow an adjustment to the average duration of a second
1059 * to compensate for differences in the actual clock rate due to temperature,
1060 * the crystal, capacitor, etc.
1061 *
1062 * The adjustment applied is as follows:
1063 * t = t0 * (1 + offset * 1e-9)
1064 * where t0 is the measured length of 1 RTC second with offset = 0
1065 *
1066 * Kernel interface to adjust an rtc clock offset.
1067 * Return 0 on success, or a negative number on error.
1068 * If the rtc offset is not setable (or not implemented), return -EINVAL
1069 */
1070int rtc_set_offset(struct rtc_device *rtc, long offset)
1071{
1072 int ret;
1073
1074 if (!rtc->ops)
1075 return -ENODEV;
1076
1077 if (!rtc->ops->set_offset)
1078 return -EINVAL;
1079
1080 mutex_lock(&rtc->ops_lock);
1081 ret = rtc->ops->set_offset(rtc->dev.parent, offset);
1082 mutex_unlock(&rtc->ops_lock);
1083
1084 trace_rtc_set_offset(offset, ret);
1085 return ret;
1086}
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 timeu64_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, uie;
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#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
141 uie = rtc->uie_rtctimer.enabled || rtc->uie_irq_active;
142#else
143 uie = rtc->uie_rtctimer.enabled;
144#endif
145 if (uie) {
146 err = rtc_update_irq_enable(rtc, 0);
147 if (err)
148 return err;
149 }
150
151 err = mutex_lock_interruptible(&rtc->ops_lock);
152 if (err)
153 return err;
154
155 if (!rtc->ops)
156 err = -ENODEV;
157 else if (rtc->ops->set_time)
158 err = rtc->ops->set_time(rtc->dev.parent, tm);
159 else
160 err = -EINVAL;
161
162 pm_stay_awake(rtc->dev.parent);
163 mutex_unlock(&rtc->ops_lock);
164 /* A timer might have just expired */
165 schedule_work(&rtc->irqwork);
166
167 if (uie) {
168 err = rtc_update_irq_enable(rtc, 1);
169 if (err)
170 return err;
171 }
172
173 trace_rtc_set_time(rtc_tm_to_time64(tm), err);
174 return err;
175}
176EXPORT_SYMBOL_GPL(rtc_set_time);
177
178static int rtc_read_alarm_internal(struct rtc_device *rtc,
179 struct rtc_wkalrm *alarm)
180{
181 int err;
182
183 err = mutex_lock_interruptible(&rtc->ops_lock);
184 if (err)
185 return err;
186
187 if (!rtc->ops) {
188 err = -ENODEV;
189 } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->read_alarm) {
190 err = -EINVAL;
191 } else {
192 alarm->enabled = 0;
193 alarm->pending = 0;
194 alarm->time.tm_sec = -1;
195 alarm->time.tm_min = -1;
196 alarm->time.tm_hour = -1;
197 alarm->time.tm_mday = -1;
198 alarm->time.tm_mon = -1;
199 alarm->time.tm_year = -1;
200 alarm->time.tm_wday = -1;
201 alarm->time.tm_yday = -1;
202 alarm->time.tm_isdst = -1;
203 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
204 }
205
206 mutex_unlock(&rtc->ops_lock);
207
208 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
209 return err;
210}
211
212int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
213{
214 int err;
215 struct rtc_time before, now;
216 int first_time = 1;
217 time64_t t_now, t_alm;
218 enum { none, day, month, year } missing = none;
219 unsigned int days;
220
221 /* The lower level RTC driver may return -1 in some fields,
222 * creating invalid alarm->time values, for reasons like:
223 *
224 * - The hardware may not be capable of filling them in;
225 * many alarms match only on time-of-day fields, not
226 * day/month/year calendar data.
227 *
228 * - Some hardware uses illegal values as "wildcard" match
229 * values, which non-Linux firmware (like a BIOS) may try
230 * to set up as e.g. "alarm 15 minutes after each hour".
231 * Linux uses only oneshot alarms.
232 *
233 * When we see that here, we deal with it by using values from
234 * a current RTC timestamp for any missing (-1) values. The
235 * RTC driver prevents "periodic alarm" modes.
236 *
237 * But this can be racey, because some fields of the RTC timestamp
238 * may have wrapped in the interval since we read the RTC alarm,
239 * which would lead to us inserting inconsistent values in place
240 * of the -1 fields.
241 *
242 * Reading the alarm and timestamp in the reverse sequence
243 * would have the same race condition, and not solve the issue.
244 *
245 * So, we must first read the RTC timestamp,
246 * then read the RTC alarm value,
247 * and then read a second RTC timestamp.
248 *
249 * If any fields of the second timestamp have changed
250 * when compared with the first timestamp, then we know
251 * our timestamp may be inconsistent with that used by
252 * the low-level rtc_read_alarm_internal() function.
253 *
254 * So, when the two timestamps disagree, we just loop and do
255 * the process again to get a fully consistent set of values.
256 *
257 * This could all instead be done in the lower level driver,
258 * but since more than one lower level RTC implementation needs it,
259 * then it's probably best to do it here instead of there..
260 */
261
262 /* Get the "before" timestamp */
263 err = rtc_read_time(rtc, &before);
264 if (err < 0)
265 return err;
266 do {
267 if (!first_time)
268 memcpy(&before, &now, sizeof(struct rtc_time));
269 first_time = 0;
270
271 /* get the RTC alarm values, which may be incomplete */
272 err = rtc_read_alarm_internal(rtc, alarm);
273 if (err)
274 return err;
275
276 /* full-function RTCs won't have such missing fields */
277 err = rtc_valid_tm(&alarm->time);
278 if (!err)
279 goto done;
280
281 /* get the "after" timestamp, to detect wrapped fields */
282 err = rtc_read_time(rtc, &now);
283 if (err < 0)
284 return err;
285
286 /* note that tm_sec is a "don't care" value here: */
287 } while (before.tm_min != now.tm_min ||
288 before.tm_hour != now.tm_hour ||
289 before.tm_mon != now.tm_mon ||
290 before.tm_year != now.tm_year);
291
292 /* Fill in the missing alarm fields using the timestamp; we
293 * know there's at least one since alarm->time is invalid.
294 */
295 if (alarm->time.tm_sec == -1)
296 alarm->time.tm_sec = now.tm_sec;
297 if (alarm->time.tm_min == -1)
298 alarm->time.tm_min = now.tm_min;
299 if (alarm->time.tm_hour == -1)
300 alarm->time.tm_hour = now.tm_hour;
301
302 /* For simplicity, only support date rollover for now */
303 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
304 alarm->time.tm_mday = now.tm_mday;
305 missing = day;
306 }
307 if ((unsigned int)alarm->time.tm_mon >= 12) {
308 alarm->time.tm_mon = now.tm_mon;
309 if (missing == none)
310 missing = month;
311 }
312 if (alarm->time.tm_year == -1) {
313 alarm->time.tm_year = now.tm_year;
314 if (missing == none)
315 missing = year;
316 }
317
318 /* Can't proceed if alarm is still invalid after replacing
319 * missing fields.
320 */
321 err = rtc_valid_tm(&alarm->time);
322 if (err)
323 goto done;
324
325 /* with luck, no rollover is needed */
326 t_now = rtc_tm_to_time64(&now);
327 t_alm = rtc_tm_to_time64(&alarm->time);
328 if (t_now < t_alm)
329 goto done;
330
331 switch (missing) {
332 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
333 * that will trigger at 5am will do so at 5am Tuesday, which
334 * could also be in the next month or year. This is a common
335 * case, especially for PCs.
336 */
337 case day:
338 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
339 t_alm += 24 * 60 * 60;
340 rtc_time64_to_tm(t_alm, &alarm->time);
341 break;
342
343 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
344 * be next month. An alarm matching on the 30th, 29th, or 28th
345 * may end up in the month after that! Many newer PCs support
346 * this type of alarm.
347 */
348 case month:
349 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
350 do {
351 if (alarm->time.tm_mon < 11) {
352 alarm->time.tm_mon++;
353 } else {
354 alarm->time.tm_mon = 0;
355 alarm->time.tm_year++;
356 }
357 days = rtc_month_days(alarm->time.tm_mon,
358 alarm->time.tm_year);
359 } while (days < alarm->time.tm_mday);
360 break;
361
362 /* Year rollover ... easy except for leap years! */
363 case year:
364 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
365 do {
366 alarm->time.tm_year++;
367 } while (!is_leap_year(alarm->time.tm_year + 1900) &&
368 rtc_valid_tm(&alarm->time) != 0);
369 break;
370
371 default:
372 dev_warn(&rtc->dev, "alarm rollover not handled\n");
373 }
374
375 err = rtc_valid_tm(&alarm->time);
376
377done:
378 if (err && alarm->enabled)
379 dev_warn(&rtc->dev, "invalid alarm value: %ptR\n",
380 &alarm->time);
381 else
382 rtc_add_offset(rtc, &alarm->time);
383
384 return err;
385}
386
387int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
388{
389 int err;
390
391 err = mutex_lock_interruptible(&rtc->ops_lock);
392 if (err)
393 return err;
394 if (!rtc->ops) {
395 err = -ENODEV;
396 } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features)) {
397 err = -EINVAL;
398 } else {
399 memset(alarm, 0, sizeof(struct rtc_wkalrm));
400 alarm->enabled = rtc->aie_timer.enabled;
401 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
402 }
403 mutex_unlock(&rtc->ops_lock);
404
405 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
406 return err;
407}
408EXPORT_SYMBOL_GPL(rtc_read_alarm);
409
410static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
411{
412 struct rtc_time tm;
413 time64_t now, scheduled;
414 int err;
415
416 err = rtc_valid_tm(&alarm->time);
417 if (err)
418 return err;
419
420 scheduled = rtc_tm_to_time64(&alarm->time);
421
422 /* Make sure we're not setting alarms in the past */
423 err = __rtc_read_time(rtc, &tm);
424 if (err)
425 return err;
426 now = rtc_tm_to_time64(&tm);
427
428 if (scheduled <= now)
429 return -ETIME;
430 /*
431 * XXX - We just checked to make sure the alarm time is not
432 * in the past, but there is still a race window where if
433 * the is alarm set for the next second and the second ticks
434 * over right here, before we set the alarm.
435 */
436
437 rtc_subtract_offset(rtc, &alarm->time);
438
439 if (!rtc->ops)
440 err = -ENODEV;
441 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
442 err = -EINVAL;
443 else
444 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
445
446 trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
447 return err;
448}
449
450int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
451{
452 ktime_t alarm_time;
453 int err;
454
455 if (!rtc->ops)
456 return -ENODEV;
457 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features))
458 return -EINVAL;
459
460 err = rtc_valid_tm(&alarm->time);
461 if (err != 0)
462 return err;
463
464 err = rtc_valid_range(rtc, &alarm->time);
465 if (err)
466 return err;
467
468 err = mutex_lock_interruptible(&rtc->ops_lock);
469 if (err)
470 return err;
471 if (rtc->aie_timer.enabled)
472 rtc_timer_remove(rtc, &rtc->aie_timer);
473
474 alarm_time = rtc_tm_to_ktime(alarm->time);
475 /*
476 * Round down so we never miss a deadline, checking for past deadline is
477 * done in __rtc_set_alarm
478 */
479 if (test_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features))
480 alarm_time = ktime_sub_ns(alarm_time, (u64)alarm->time.tm_sec * NSEC_PER_SEC);
481
482 rtc->aie_timer.node.expires = alarm_time;
483 rtc->aie_timer.period = 0;
484 if (alarm->enabled)
485 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
486
487 mutex_unlock(&rtc->ops_lock);
488
489 return err;
490}
491EXPORT_SYMBOL_GPL(rtc_set_alarm);
492
493/* Called once per device from rtc_device_register */
494int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
495{
496 int err;
497 struct rtc_time now;
498
499 err = rtc_valid_tm(&alarm->time);
500 if (err != 0)
501 return err;
502
503 err = rtc_read_time(rtc, &now);
504 if (err)
505 return err;
506
507 err = mutex_lock_interruptible(&rtc->ops_lock);
508 if (err)
509 return err;
510
511 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
512 rtc->aie_timer.period = 0;
513
514 /* Alarm has to be enabled & in the future for us to enqueue it */
515 if (alarm->enabled && (rtc_tm_to_ktime(now) <
516 rtc->aie_timer.node.expires)) {
517 rtc->aie_timer.enabled = 1;
518 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
519 trace_rtc_timer_enqueue(&rtc->aie_timer);
520 }
521 mutex_unlock(&rtc->ops_lock);
522 return err;
523}
524EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
525
526int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
527{
528 int err;
529
530 err = mutex_lock_interruptible(&rtc->ops_lock);
531 if (err)
532 return err;
533
534 if (rtc->aie_timer.enabled != enabled) {
535 if (enabled)
536 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
537 else
538 rtc_timer_remove(rtc, &rtc->aie_timer);
539 }
540
541 if (err)
542 /* nothing */;
543 else if (!rtc->ops)
544 err = -ENODEV;
545 else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
546 err = -EINVAL;
547 else
548 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
549
550 mutex_unlock(&rtc->ops_lock);
551
552 trace_rtc_alarm_irq_enable(enabled, err);
553 return err;
554}
555EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
556
557int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
558{
559 int err;
560
561 err = mutex_lock_interruptible(&rtc->ops_lock);
562 if (err)
563 return err;
564
565#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
566 if (enabled == 0 && rtc->uie_irq_active) {
567 mutex_unlock(&rtc->ops_lock);
568 return rtc_dev_update_irq_enable_emul(rtc, 0);
569 }
570#endif
571 /* make sure we're changing state */
572 if (rtc->uie_rtctimer.enabled == enabled)
573 goto out;
574
575 if (!test_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features) ||
576 !test_bit(RTC_FEATURE_ALARM, rtc->features)) {
577 mutex_unlock(&rtc->ops_lock);
578#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
579 return rtc_dev_update_irq_enable_emul(rtc, enabled);
580#else
581 return -EINVAL;
582#endif
583 }
584
585 if (enabled) {
586 struct rtc_time tm;
587 ktime_t now, onesec;
588
589 err = __rtc_read_time(rtc, &tm);
590 if (err)
591 goto out;
592 onesec = ktime_set(1, 0);
593 now = rtc_tm_to_ktime(tm);
594 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
595 rtc->uie_rtctimer.period = ktime_set(1, 0);
596 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
597 } else {
598 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
599 }
600
601out:
602 mutex_unlock(&rtc->ops_lock);
603
604 return err;
605}
606EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
607
608/**
609 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
610 * @rtc: pointer to the rtc device
611 * @num: number of occurence of the event
612 * @mode: type of the event, RTC_AF, RTC_UF of RTC_PF
613 *
614 * This function is called when an AIE, UIE or PIE mode interrupt
615 * has occurred (or been emulated).
616 *
617 */
618void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
619{
620 unsigned long flags;
621
622 /* mark one irq of the appropriate mode */
623 spin_lock_irqsave(&rtc->irq_lock, flags);
624 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF | mode);
625 spin_unlock_irqrestore(&rtc->irq_lock, flags);
626
627 wake_up_interruptible(&rtc->irq_queue);
628 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
629}
630
631/**
632 * rtc_aie_update_irq - AIE mode rtctimer hook
633 * @rtc: pointer to the rtc_device
634 *
635 * This functions is called when the aie_timer expires.
636 */
637void rtc_aie_update_irq(struct rtc_device *rtc)
638{
639 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
640}
641
642/**
643 * rtc_uie_update_irq - UIE mode rtctimer hook
644 * @rtc: pointer to the rtc_device
645 *
646 * This functions is called when the uie_timer expires.
647 */
648void rtc_uie_update_irq(struct rtc_device *rtc)
649{
650 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
651}
652
653/**
654 * rtc_pie_update_irq - PIE mode hrtimer hook
655 * @timer: pointer to the pie mode hrtimer
656 *
657 * This function is used to emulate PIE mode interrupts
658 * using an hrtimer. This function is called when the periodic
659 * hrtimer expires.
660 */
661enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
662{
663 struct rtc_device *rtc;
664 ktime_t period;
665 u64 count;
666
667 rtc = container_of(timer, struct rtc_device, pie_timer);
668
669 period = NSEC_PER_SEC / rtc->irq_freq;
670 count = hrtimer_forward_now(timer, period);
671
672 rtc_handle_legacy_irq(rtc, count, RTC_PF);
673
674 return HRTIMER_RESTART;
675}
676
677/**
678 * rtc_update_irq - Triggered when a RTC interrupt occurs.
679 * @rtc: the rtc device
680 * @num: how many irqs are being reported (usually one)
681 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
682 * Context: any
683 */
684void rtc_update_irq(struct rtc_device *rtc,
685 unsigned long num, unsigned long events)
686{
687 if (IS_ERR_OR_NULL(rtc))
688 return;
689
690 pm_stay_awake(rtc->dev.parent);
691 schedule_work(&rtc->irqwork);
692}
693EXPORT_SYMBOL_GPL(rtc_update_irq);
694
695struct rtc_device *rtc_class_open(const char *name)
696{
697 struct device *dev;
698 struct rtc_device *rtc = NULL;
699
700 dev = class_find_device_by_name(&rtc_class, name);
701 if (dev)
702 rtc = to_rtc_device(dev);
703
704 if (rtc) {
705 if (!try_module_get(rtc->owner)) {
706 put_device(dev);
707 rtc = NULL;
708 }
709 }
710
711 return rtc;
712}
713EXPORT_SYMBOL_GPL(rtc_class_open);
714
715void rtc_class_close(struct rtc_device *rtc)
716{
717 module_put(rtc->owner);
718 put_device(&rtc->dev);
719}
720EXPORT_SYMBOL_GPL(rtc_class_close);
721
722static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
723{
724 /*
725 * We always cancel the timer here first, because otherwise
726 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
727 * when we manage to start the timer before the callback
728 * returns HRTIMER_RESTART.
729 *
730 * We cannot use hrtimer_cancel() here as a running callback
731 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
732 * would spin forever.
733 */
734 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
735 return -1;
736
737 if (enabled) {
738 ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
739
740 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
741 }
742 return 0;
743}
744
745/**
746 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
747 * @rtc: the rtc device
748 * @enabled: true to enable periodic IRQs
749 * Context: any
750 *
751 * Note that rtc_irq_set_freq() should previously have been used to
752 * specify the desired frequency of periodic IRQ.
753 */
754int rtc_irq_set_state(struct rtc_device *rtc, int enabled)
755{
756 int err = 0;
757
758 while (rtc_update_hrtimer(rtc, enabled) < 0)
759 cpu_relax();
760
761 rtc->pie_enabled = enabled;
762
763 trace_rtc_irq_set_state(enabled, err);
764 return err;
765}
766
767/**
768 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
769 * @rtc: the rtc device
770 * @freq: positive frequency
771 * Context: any
772 *
773 * Note that rtc_irq_set_state() is used to enable or disable the
774 * periodic IRQs.
775 */
776int rtc_irq_set_freq(struct rtc_device *rtc, int freq)
777{
778 int err = 0;
779
780 if (freq <= 0 || freq > RTC_MAX_FREQ)
781 return -EINVAL;
782
783 rtc->irq_freq = freq;
784 while (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0)
785 cpu_relax();
786
787 trace_rtc_irq_set_freq(freq, err);
788 return err;
789}
790
791/**
792 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
793 * @rtc: rtc device
794 * @timer: timer being added.
795 *
796 * Enqueues a timer onto the rtc devices timerqueue and sets
797 * the next alarm event appropriately.
798 *
799 * Sets the enabled bit on the added timer.
800 *
801 * Must hold ops_lock for proper serialization of timerqueue
802 */
803static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
804{
805 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
806 struct rtc_time tm;
807 ktime_t now;
808 int err;
809
810 err = __rtc_read_time(rtc, &tm);
811 if (err)
812 return err;
813
814 timer->enabled = 1;
815 now = rtc_tm_to_ktime(tm);
816
817 /* Skip over expired timers */
818 while (next) {
819 if (next->expires >= now)
820 break;
821 next = timerqueue_iterate_next(next);
822 }
823
824 timerqueue_add(&rtc->timerqueue, &timer->node);
825 trace_rtc_timer_enqueue(timer);
826 if (!next || ktime_before(timer->node.expires, next->expires)) {
827 struct rtc_wkalrm alarm;
828
829 alarm.time = rtc_ktime_to_tm(timer->node.expires);
830 alarm.enabled = 1;
831 err = __rtc_set_alarm(rtc, &alarm);
832 if (err == -ETIME) {
833 pm_stay_awake(rtc->dev.parent);
834 schedule_work(&rtc->irqwork);
835 } else if (err) {
836 timerqueue_del(&rtc->timerqueue, &timer->node);
837 trace_rtc_timer_dequeue(timer);
838 timer->enabled = 0;
839 return err;
840 }
841 }
842 return 0;
843}
844
845static void rtc_alarm_disable(struct rtc_device *rtc)
846{
847 if (!rtc->ops || !test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable)
848 return;
849
850 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
851 trace_rtc_alarm_irq_enable(0, 0);
852}
853
854/**
855 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
856 * @rtc: rtc device
857 * @timer: timer being removed.
858 *
859 * Removes a timer onto the rtc devices timerqueue and sets
860 * the next alarm event appropriately.
861 *
862 * Clears the enabled bit on the removed timer.
863 *
864 * Must hold ops_lock for proper serialization of timerqueue
865 */
866static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
867{
868 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
869
870 timerqueue_del(&rtc->timerqueue, &timer->node);
871 trace_rtc_timer_dequeue(timer);
872 timer->enabled = 0;
873 if (next == &timer->node) {
874 struct rtc_wkalrm alarm;
875 int err;
876
877 next = timerqueue_getnext(&rtc->timerqueue);
878 if (!next) {
879 rtc_alarm_disable(rtc);
880 return;
881 }
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 pm_stay_awake(rtc->dev.parent);
887 schedule_work(&rtc->irqwork);
888 }
889 }
890}
891
892/**
893 * rtc_timer_do_work - Expires rtc timers
894 * @work: work item
895 *
896 * Expires rtc timers. Reprograms next alarm event if needed.
897 * Called via worktask.
898 *
899 * Serializes access to timerqueue via ops_lock mutex
900 */
901void rtc_timer_do_work(struct work_struct *work)
902{
903 struct rtc_timer *timer;
904 struct timerqueue_node *next;
905 ktime_t now;
906 struct rtc_time tm;
907 int err;
908
909 struct rtc_device *rtc =
910 container_of(work, struct rtc_device, irqwork);
911
912 mutex_lock(&rtc->ops_lock);
913again:
914 err = __rtc_read_time(rtc, &tm);
915 if (err) {
916 mutex_unlock(&rtc->ops_lock);
917 return;
918 }
919 now = rtc_tm_to_ktime(tm);
920 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
921 if (next->expires > now)
922 break;
923
924 /* expire timer */
925 timer = container_of(next, struct rtc_timer, node);
926 timerqueue_del(&rtc->timerqueue, &timer->node);
927 trace_rtc_timer_dequeue(timer);
928 timer->enabled = 0;
929 if (timer->func)
930 timer->func(timer->rtc);
931
932 trace_rtc_timer_fired(timer);
933 /* Re-add/fwd periodic timers */
934 if (ktime_to_ns(timer->period)) {
935 timer->node.expires = ktime_add(timer->node.expires,
936 timer->period);
937 timer->enabled = 1;
938 timerqueue_add(&rtc->timerqueue, &timer->node);
939 trace_rtc_timer_enqueue(timer);
940 }
941 }
942
943 /* Set next alarm */
944 if (next) {
945 struct rtc_wkalrm alarm;
946 int err;
947 int retry = 3;
948
949 alarm.time = rtc_ktime_to_tm(next->expires);
950 alarm.enabled = 1;
951reprogram:
952 err = __rtc_set_alarm(rtc, &alarm);
953 if (err == -ETIME) {
954 goto again;
955 } else if (err) {
956 if (retry-- > 0)
957 goto reprogram;
958
959 timer = container_of(next, struct rtc_timer, node);
960 timerqueue_del(&rtc->timerqueue, &timer->node);
961 trace_rtc_timer_dequeue(timer);
962 timer->enabled = 0;
963 dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
964 goto again;
965 }
966 } else {
967 rtc_alarm_disable(rtc);
968 }
969
970 pm_relax(rtc->dev.parent);
971 mutex_unlock(&rtc->ops_lock);
972}
973
974/* rtc_timer_init - Initializes an rtc_timer
975 * @timer: timer to be intiialized
976 * @f: function pointer to be called when timer fires
977 * @rtc: pointer to the rtc_device
978 *
979 * Kernel interface to initializing an rtc_timer.
980 */
981void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
982 struct rtc_device *rtc)
983{
984 timerqueue_init(&timer->node);
985 timer->enabled = 0;
986 timer->func = f;
987 timer->rtc = rtc;
988}
989
990/* rtc_timer_start - Sets an rtc_timer to fire in the future
991 * @ rtc: rtc device to be used
992 * @ timer: timer being set
993 * @ expires: time at which to expire the timer
994 * @ period: period that the timer will recur
995 *
996 * Kernel interface to set an rtc_timer
997 */
998int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
999 ktime_t expires, ktime_t period)
1000{
1001 int ret = 0;
1002
1003 mutex_lock(&rtc->ops_lock);
1004 if (timer->enabled)
1005 rtc_timer_remove(rtc, timer);
1006
1007 timer->node.expires = expires;
1008 timer->period = period;
1009
1010 ret = rtc_timer_enqueue(rtc, timer);
1011
1012 mutex_unlock(&rtc->ops_lock);
1013 return ret;
1014}
1015
1016/* rtc_timer_cancel - Stops an rtc_timer
1017 * @ rtc: rtc device to be used
1018 * @ timer: timer being set
1019 *
1020 * Kernel interface to cancel an rtc_timer
1021 */
1022void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
1023{
1024 mutex_lock(&rtc->ops_lock);
1025 if (timer->enabled)
1026 rtc_timer_remove(rtc, timer);
1027 mutex_unlock(&rtc->ops_lock);
1028}
1029
1030/**
1031 * rtc_read_offset - Read the amount of rtc offset in parts per billion
1032 * @rtc: rtc device to be used
1033 * @offset: the offset in parts per billion
1034 *
1035 * see below for details.
1036 *
1037 * Kernel interface to read rtc clock offset
1038 * Returns 0 on success, or a negative number on error.
1039 * If read_offset() is not implemented for the rtc, return -EINVAL
1040 */
1041int rtc_read_offset(struct rtc_device *rtc, long *offset)
1042{
1043 int ret;
1044
1045 if (!rtc->ops)
1046 return -ENODEV;
1047
1048 if (!rtc->ops->read_offset)
1049 return -EINVAL;
1050
1051 mutex_lock(&rtc->ops_lock);
1052 ret = rtc->ops->read_offset(rtc->dev.parent, offset);
1053 mutex_unlock(&rtc->ops_lock);
1054
1055 trace_rtc_read_offset(*offset, ret);
1056 return ret;
1057}
1058
1059/**
1060 * rtc_set_offset - Adjusts the duration of the average second
1061 * @rtc: rtc device to be used
1062 * @offset: the offset in parts per billion
1063 *
1064 * Some rtc's allow an adjustment to the average duration of a second
1065 * to compensate for differences in the actual clock rate due to temperature,
1066 * the crystal, capacitor, etc.
1067 *
1068 * The adjustment applied is as follows:
1069 * t = t0 * (1 + offset * 1e-9)
1070 * where t0 is the measured length of 1 RTC second with offset = 0
1071 *
1072 * Kernel interface to adjust an rtc clock offset.
1073 * Return 0 on success, or a negative number on error.
1074 * If the rtc offset is not setable (or not implemented), return -EINVAL
1075 */
1076int rtc_set_offset(struct rtc_device *rtc, long offset)
1077{
1078 int ret;
1079
1080 if (!rtc->ops)
1081 return -ENODEV;
1082
1083 if (!rtc->ops->set_offset)
1084 return -EINVAL;
1085
1086 mutex_lock(&rtc->ops_lock);
1087 ret = rtc->ops->set_offset(rtc->dev.parent, offset);
1088 mutex_unlock(&rtc->ops_lock);
1089
1090 trace_rtc_set_offset(offset, ret);
1091 return ret;
1092}