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