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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/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
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 if (err < 0) {
34 dev_dbg(&rtc->dev, "read_time: fail to read: %d\n",
35 err);
36 return err;
37 }
38
39 err = rtc_valid_tm(tm);
40 if (err < 0)
41 dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n");
42 }
43 return err;
44}
45
46int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
47{
48 int err;
49
50 err = mutex_lock_interruptible(&rtc->ops_lock);
51 if (err)
52 return err;
53
54 err = __rtc_read_time(rtc, tm);
55 mutex_unlock(&rtc->ops_lock);
56 return err;
57}
58EXPORT_SYMBOL_GPL(rtc_read_time);
59
60int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
61{
62 int err;
63
64 err = rtc_valid_tm(tm);
65 if (err != 0)
66 return err;
67
68 err = mutex_lock_interruptible(&rtc->ops_lock);
69 if (err)
70 return err;
71
72 if (!rtc->ops)
73 err = -ENODEV;
74 else if (rtc->ops->set_time)
75 err = rtc->ops->set_time(rtc->dev.parent, tm);
76 else if (rtc->ops->set_mmss64) {
77 time64_t secs64 = rtc_tm_to_time64(tm);
78
79 err = rtc->ops->set_mmss64(rtc->dev.parent, secs64);
80 } else if (rtc->ops->set_mmss) {
81 time64_t secs64 = rtc_tm_to_time64(tm);
82 err = rtc->ops->set_mmss(rtc->dev.parent, secs64);
83 } else
84 err = -EINVAL;
85
86 pm_stay_awake(rtc->dev.parent);
87 mutex_unlock(&rtc->ops_lock);
88 /* A timer might have just expired */
89 schedule_work(&rtc->irqwork);
90 return err;
91}
92EXPORT_SYMBOL_GPL(rtc_set_time);
93
94static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
95{
96 int err;
97
98 err = mutex_lock_interruptible(&rtc->ops_lock);
99 if (err)
100 return err;
101
102 if (rtc->ops == NULL)
103 err = -ENODEV;
104 else if (!rtc->ops->read_alarm)
105 err = -EINVAL;
106 else {
107 memset(alarm, 0, sizeof(struct rtc_wkalrm));
108 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
109 }
110
111 mutex_unlock(&rtc->ops_lock);
112 return err;
113}
114
115int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
116{
117 int err;
118 struct rtc_time before, now;
119 int first_time = 1;
120 time64_t t_now, t_alm;
121 enum { none, day, month, year } missing = none;
122 unsigned days;
123
124 /* The lower level RTC driver may return -1 in some fields,
125 * creating invalid alarm->time values, for reasons like:
126 *
127 * - The hardware may not be capable of filling them in;
128 * many alarms match only on time-of-day fields, not
129 * day/month/year calendar data.
130 *
131 * - Some hardware uses illegal values as "wildcard" match
132 * values, which non-Linux firmware (like a BIOS) may try
133 * to set up as e.g. "alarm 15 minutes after each hour".
134 * Linux uses only oneshot alarms.
135 *
136 * When we see that here, we deal with it by using values from
137 * a current RTC timestamp for any missing (-1) values. The
138 * RTC driver prevents "periodic alarm" modes.
139 *
140 * But this can be racey, because some fields of the RTC timestamp
141 * may have wrapped in the interval since we read the RTC alarm,
142 * which would lead to us inserting inconsistent values in place
143 * of the -1 fields.
144 *
145 * Reading the alarm and timestamp in the reverse sequence
146 * would have the same race condition, and not solve the issue.
147 *
148 * So, we must first read the RTC timestamp,
149 * then read the RTC alarm value,
150 * and then read a second RTC timestamp.
151 *
152 * If any fields of the second timestamp have changed
153 * when compared with the first timestamp, then we know
154 * our timestamp may be inconsistent with that used by
155 * the low-level rtc_read_alarm_internal() function.
156 *
157 * So, when the two timestamps disagree, we just loop and do
158 * the process again to get a fully consistent set of values.
159 *
160 * This could all instead be done in the lower level driver,
161 * but since more than one lower level RTC implementation needs it,
162 * then it's probably best best to do it here instead of there..
163 */
164
165 /* Get the "before" timestamp */
166 err = rtc_read_time(rtc, &before);
167 if (err < 0)
168 return err;
169 do {
170 if (!first_time)
171 memcpy(&before, &now, sizeof(struct rtc_time));
172 first_time = 0;
173
174 /* get the RTC alarm values, which may be incomplete */
175 err = rtc_read_alarm_internal(rtc, alarm);
176 if (err)
177 return err;
178
179 /* full-function RTCs won't have such missing fields */
180 if (rtc_valid_tm(&alarm->time) == 0)
181 return 0;
182
183 /* get the "after" timestamp, to detect wrapped fields */
184 err = rtc_read_time(rtc, &now);
185 if (err < 0)
186 return err;
187
188 /* note that tm_sec is a "don't care" value here: */
189 } while ( before.tm_min != now.tm_min
190 || before.tm_hour != now.tm_hour
191 || before.tm_mon != now.tm_mon
192 || before.tm_year != now.tm_year);
193
194 /* Fill in the missing alarm fields using the timestamp; we
195 * know there's at least one since alarm->time is invalid.
196 */
197 if (alarm->time.tm_sec == -1)
198 alarm->time.tm_sec = now.tm_sec;
199 if (alarm->time.tm_min == -1)
200 alarm->time.tm_min = now.tm_min;
201 if (alarm->time.tm_hour == -1)
202 alarm->time.tm_hour = now.tm_hour;
203
204 /* For simplicity, only support date rollover for now */
205 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
206 alarm->time.tm_mday = now.tm_mday;
207 missing = day;
208 }
209 if ((unsigned)alarm->time.tm_mon >= 12) {
210 alarm->time.tm_mon = now.tm_mon;
211 if (missing == none)
212 missing = month;
213 }
214 if (alarm->time.tm_year == -1) {
215 alarm->time.tm_year = now.tm_year;
216 if (missing == none)
217 missing = year;
218 }
219
220 /* with luck, no rollover is needed */
221 t_now = rtc_tm_to_time64(&now);
222 t_alm = rtc_tm_to_time64(&alarm->time);
223 if (t_now < t_alm)
224 goto done;
225
226 switch (missing) {
227
228 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
229 * that will trigger at 5am will do so at 5am Tuesday, which
230 * could also be in the next month or year. This is a common
231 * case, especially for PCs.
232 */
233 case day:
234 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
235 t_alm += 24 * 60 * 60;
236 rtc_time64_to_tm(t_alm, &alarm->time);
237 break;
238
239 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
240 * be next month. An alarm matching on the 30th, 29th, or 28th
241 * may end up in the month after that! Many newer PCs support
242 * this type of alarm.
243 */
244 case month:
245 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
246 do {
247 if (alarm->time.tm_mon < 11)
248 alarm->time.tm_mon++;
249 else {
250 alarm->time.tm_mon = 0;
251 alarm->time.tm_year++;
252 }
253 days = rtc_month_days(alarm->time.tm_mon,
254 alarm->time.tm_year);
255 } while (days < alarm->time.tm_mday);
256 break;
257
258 /* Year rollover ... easy except for leap years! */
259 case year:
260 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
261 do {
262 alarm->time.tm_year++;
263 } while (!is_leap_year(alarm->time.tm_year + 1900)
264 && rtc_valid_tm(&alarm->time) != 0);
265 break;
266
267 default:
268 dev_warn(&rtc->dev, "alarm rollover not handled\n");
269 }
270
271done:
272 err = rtc_valid_tm(&alarm->time);
273
274 if (err) {
275 dev_warn(&rtc->dev, "invalid alarm value: %d-%d-%d %d:%d:%d\n",
276 alarm->time.tm_year + 1900, alarm->time.tm_mon + 1,
277 alarm->time.tm_mday, alarm->time.tm_hour, alarm->time.tm_min,
278 alarm->time.tm_sec);
279 }
280
281 return err;
282}
283
284int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
285{
286 int err;
287
288 err = mutex_lock_interruptible(&rtc->ops_lock);
289 if (err)
290 return err;
291 if (rtc->ops == NULL)
292 err = -ENODEV;
293 else if (!rtc->ops->read_alarm)
294 err = -EINVAL;
295 else {
296 memset(alarm, 0, sizeof(struct rtc_wkalrm));
297 alarm->enabled = rtc->aie_timer.enabled;
298 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
299 }
300 mutex_unlock(&rtc->ops_lock);
301
302 return err;
303}
304EXPORT_SYMBOL_GPL(rtc_read_alarm);
305
306static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
307{
308 struct rtc_time tm;
309 time64_t now, scheduled;
310 int err;
311
312 err = rtc_valid_tm(&alarm->time);
313 if (err)
314 return err;
315 scheduled = rtc_tm_to_time64(&alarm->time);
316
317 /* Make sure we're not setting alarms in the past */
318 err = __rtc_read_time(rtc, &tm);
319 if (err)
320 return err;
321 now = rtc_tm_to_time64(&tm);
322 if (scheduled <= now)
323 return -ETIME;
324 /*
325 * XXX - We just checked to make sure the alarm time is not
326 * in the past, but there is still a race window where if
327 * the is alarm set for the next second and the second ticks
328 * over right here, before we set the alarm.
329 */
330
331 if (!rtc->ops)
332 err = -ENODEV;
333 else if (!rtc->ops->set_alarm)
334 err = -EINVAL;
335 else
336 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
337
338 return err;
339}
340
341int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
342{
343 int err;
344
345 err = rtc_valid_tm(&alarm->time);
346 if (err != 0)
347 return err;
348
349 err = mutex_lock_interruptible(&rtc->ops_lock);
350 if (err)
351 return err;
352 if (rtc->aie_timer.enabled)
353 rtc_timer_remove(rtc, &rtc->aie_timer);
354
355 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
356 rtc->aie_timer.period = ktime_set(0, 0);
357 if (alarm->enabled)
358 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
359
360 mutex_unlock(&rtc->ops_lock);
361 return err;
362}
363EXPORT_SYMBOL_GPL(rtc_set_alarm);
364
365/* Called once per device from rtc_device_register */
366int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
367{
368 int err;
369 struct rtc_time now;
370
371 err = rtc_valid_tm(&alarm->time);
372 if (err != 0)
373 return err;
374
375 err = rtc_read_time(rtc, &now);
376 if (err)
377 return err;
378
379 err = mutex_lock_interruptible(&rtc->ops_lock);
380 if (err)
381 return err;
382
383 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
384 rtc->aie_timer.period = ktime_set(0, 0);
385
386 /* Alarm has to be enabled & in the futrure for us to enqueue it */
387 if (alarm->enabled && (rtc_tm_to_ktime(now).tv64 <
388 rtc->aie_timer.node.expires.tv64)) {
389
390 rtc->aie_timer.enabled = 1;
391 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
392 }
393 mutex_unlock(&rtc->ops_lock);
394 return err;
395}
396EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
397
398
399
400int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
401{
402 int err = mutex_lock_interruptible(&rtc->ops_lock);
403 if (err)
404 return err;
405
406 if (rtc->aie_timer.enabled != enabled) {
407 if (enabled)
408 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
409 else
410 rtc_timer_remove(rtc, &rtc->aie_timer);
411 }
412
413 if (err)
414 /* nothing */;
415 else if (!rtc->ops)
416 err = -ENODEV;
417 else if (!rtc->ops->alarm_irq_enable)
418 err = -EINVAL;
419 else
420 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
421
422 mutex_unlock(&rtc->ops_lock);
423 return err;
424}
425EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
426
427int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
428{
429 int err = mutex_lock_interruptible(&rtc->ops_lock);
430 if (err)
431 return err;
432
433#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
434 if (enabled == 0 && rtc->uie_irq_active) {
435 mutex_unlock(&rtc->ops_lock);
436 return rtc_dev_update_irq_enable_emul(rtc, 0);
437 }
438#endif
439 /* make sure we're changing state */
440 if (rtc->uie_rtctimer.enabled == enabled)
441 goto out;
442
443 if (rtc->uie_unsupported) {
444 err = -EINVAL;
445 goto out;
446 }
447
448 if (enabled) {
449 struct rtc_time tm;
450 ktime_t now, onesec;
451
452 __rtc_read_time(rtc, &tm);
453 onesec = ktime_set(1, 0);
454 now = rtc_tm_to_ktime(tm);
455 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
456 rtc->uie_rtctimer.period = ktime_set(1, 0);
457 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
458 } else
459 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
460
461out:
462 mutex_unlock(&rtc->ops_lock);
463#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
464 /*
465 * Enable emulation if the driver did not provide
466 * the update_irq_enable function pointer or if returned
467 * -EINVAL to signal that it has been configured without
468 * interrupts or that are not available at the moment.
469 */
470 if (err == -EINVAL)
471 err = rtc_dev_update_irq_enable_emul(rtc, enabled);
472#endif
473 return err;
474
475}
476EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
477
478
479/**
480 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
481 * @rtc: pointer to the rtc device
482 *
483 * This function is called when an AIE, UIE or PIE mode interrupt
484 * has occurred (or been emulated).
485 *
486 * Triggers the registered irq_task function callback.
487 */
488void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
489{
490 unsigned long flags;
491
492 /* mark one irq of the appropriate mode */
493 spin_lock_irqsave(&rtc->irq_lock, flags);
494 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
495 spin_unlock_irqrestore(&rtc->irq_lock, flags);
496
497 /* call the task func */
498 spin_lock_irqsave(&rtc->irq_task_lock, flags);
499 if (rtc->irq_task)
500 rtc->irq_task->func(rtc->irq_task->private_data);
501 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
502
503 wake_up_interruptible(&rtc->irq_queue);
504 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
505}
506
507
508/**
509 * rtc_aie_update_irq - AIE mode rtctimer hook
510 * @private: pointer to the rtc_device
511 *
512 * This functions is called when the aie_timer expires.
513 */
514void rtc_aie_update_irq(void *private)
515{
516 struct rtc_device *rtc = (struct rtc_device *)private;
517 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
518}
519
520
521/**
522 * rtc_uie_update_irq - UIE mode rtctimer hook
523 * @private: pointer to the rtc_device
524 *
525 * This functions is called when the uie_timer expires.
526 */
527void rtc_uie_update_irq(void *private)
528{
529 struct rtc_device *rtc = (struct rtc_device *)private;
530 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
531}
532
533
534/**
535 * rtc_pie_update_irq - PIE mode hrtimer hook
536 * @timer: pointer to the pie mode hrtimer
537 *
538 * This function is used to emulate PIE mode interrupts
539 * using an hrtimer. This function is called when the periodic
540 * hrtimer expires.
541 */
542enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
543{
544 struct rtc_device *rtc;
545 ktime_t period;
546 int count;
547 rtc = container_of(timer, struct rtc_device, pie_timer);
548
549 period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
550 count = hrtimer_forward_now(timer, period);
551
552 rtc_handle_legacy_irq(rtc, count, RTC_PF);
553
554 return HRTIMER_RESTART;
555}
556
557/**
558 * rtc_update_irq - Triggered when a RTC interrupt occurs.
559 * @rtc: the rtc device
560 * @num: how many irqs are being reported (usually one)
561 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
562 * Context: any
563 */
564void rtc_update_irq(struct rtc_device *rtc,
565 unsigned long num, unsigned long events)
566{
567 if (IS_ERR_OR_NULL(rtc))
568 return;
569
570 pm_stay_awake(rtc->dev.parent);
571 schedule_work(&rtc->irqwork);
572}
573EXPORT_SYMBOL_GPL(rtc_update_irq);
574
575static int __rtc_match(struct device *dev, const void *data)
576{
577 const char *name = data;
578
579 if (strcmp(dev_name(dev), name) == 0)
580 return 1;
581 return 0;
582}
583
584struct rtc_device *rtc_class_open(const char *name)
585{
586 struct device *dev;
587 struct rtc_device *rtc = NULL;
588
589 dev = class_find_device(rtc_class, NULL, name, __rtc_match);
590 if (dev)
591 rtc = to_rtc_device(dev);
592
593 if (rtc) {
594 if (!try_module_get(rtc->owner)) {
595 put_device(dev);
596 rtc = NULL;
597 }
598 }
599
600 return rtc;
601}
602EXPORT_SYMBOL_GPL(rtc_class_open);
603
604void rtc_class_close(struct rtc_device *rtc)
605{
606 module_put(rtc->owner);
607 put_device(&rtc->dev);
608}
609EXPORT_SYMBOL_GPL(rtc_class_close);
610
611int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
612{
613 int retval = -EBUSY;
614
615 if (task == NULL || task->func == NULL)
616 return -EINVAL;
617
618 /* Cannot register while the char dev is in use */
619 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
620 return -EBUSY;
621
622 spin_lock_irq(&rtc->irq_task_lock);
623 if (rtc->irq_task == NULL) {
624 rtc->irq_task = task;
625 retval = 0;
626 }
627 spin_unlock_irq(&rtc->irq_task_lock);
628
629 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
630
631 return retval;
632}
633EXPORT_SYMBOL_GPL(rtc_irq_register);
634
635void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
636{
637 spin_lock_irq(&rtc->irq_task_lock);
638 if (rtc->irq_task == task)
639 rtc->irq_task = NULL;
640 spin_unlock_irq(&rtc->irq_task_lock);
641}
642EXPORT_SYMBOL_GPL(rtc_irq_unregister);
643
644static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
645{
646 /*
647 * We always cancel the timer here first, because otherwise
648 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
649 * when we manage to start the timer before the callback
650 * returns HRTIMER_RESTART.
651 *
652 * We cannot use hrtimer_cancel() here as a running callback
653 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
654 * would spin forever.
655 */
656 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
657 return -1;
658
659 if (enabled) {
660 ktime_t period = ktime_set(0, NSEC_PER_SEC / rtc->irq_freq);
661
662 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
663 }
664 return 0;
665}
666
667/**
668 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
669 * @rtc: the rtc device
670 * @task: currently registered with rtc_irq_register()
671 * @enabled: true to enable periodic IRQs
672 * Context: any
673 *
674 * Note that rtc_irq_set_freq() should previously have been used to
675 * specify the desired frequency of periodic IRQ task->func() callbacks.
676 */
677int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
678{
679 int err = 0;
680 unsigned long flags;
681
682retry:
683 spin_lock_irqsave(&rtc->irq_task_lock, flags);
684 if (rtc->irq_task != NULL && task == NULL)
685 err = -EBUSY;
686 else if (rtc->irq_task != task)
687 err = -EACCES;
688 else {
689 if (rtc_update_hrtimer(rtc, enabled) < 0) {
690 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
691 cpu_relax();
692 goto retry;
693 }
694 rtc->pie_enabled = enabled;
695 }
696 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
697 return err;
698}
699EXPORT_SYMBOL_GPL(rtc_irq_set_state);
700
701/**
702 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
703 * @rtc: the rtc device
704 * @task: currently registered with rtc_irq_register()
705 * @freq: positive frequency with which task->func() will be called
706 * Context: any
707 *
708 * Note that rtc_irq_set_state() is used to enable or disable the
709 * periodic IRQs.
710 */
711int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
712{
713 int err = 0;
714 unsigned long flags;
715
716 if (freq <= 0 || freq > RTC_MAX_FREQ)
717 return -EINVAL;
718retry:
719 spin_lock_irqsave(&rtc->irq_task_lock, flags);
720 if (rtc->irq_task != NULL && task == NULL)
721 err = -EBUSY;
722 else if (rtc->irq_task != task)
723 err = -EACCES;
724 else {
725 rtc->irq_freq = freq;
726 if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) {
727 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
728 cpu_relax();
729 goto retry;
730 }
731 }
732 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
733 return err;
734}
735EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
736
737/**
738 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
739 * @rtc rtc device
740 * @timer timer being added.
741 *
742 * Enqueues a timer onto the rtc devices timerqueue and sets
743 * the next alarm event appropriately.
744 *
745 * Sets the enabled bit on the added timer.
746 *
747 * Must hold ops_lock for proper serialization of timerqueue
748 */
749static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
750{
751 timer->enabled = 1;
752 timerqueue_add(&rtc->timerqueue, &timer->node);
753 if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) {
754 struct rtc_wkalrm alarm;
755 int err;
756 alarm.time = rtc_ktime_to_tm(timer->node.expires);
757 alarm.enabled = 1;
758 err = __rtc_set_alarm(rtc, &alarm);
759 if (err == -ETIME) {
760 pm_stay_awake(rtc->dev.parent);
761 schedule_work(&rtc->irqwork);
762 } else if (err) {
763 timerqueue_del(&rtc->timerqueue, &timer->node);
764 timer->enabled = 0;
765 return err;
766 }
767 }
768 return 0;
769}
770
771static void rtc_alarm_disable(struct rtc_device *rtc)
772{
773 if (!rtc->ops || !rtc->ops->alarm_irq_enable)
774 return;
775
776 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
777}
778
779/**
780 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
781 * @rtc rtc device
782 * @timer timer being removed.
783 *
784 * Removes a timer onto the rtc devices timerqueue and sets
785 * the next alarm event appropriately.
786 *
787 * Clears the enabled bit on the removed timer.
788 *
789 * Must hold ops_lock for proper serialization of timerqueue
790 */
791static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
792{
793 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
794 timerqueue_del(&rtc->timerqueue, &timer->node);
795 timer->enabled = 0;
796 if (next == &timer->node) {
797 struct rtc_wkalrm alarm;
798 int err;
799 next = timerqueue_getnext(&rtc->timerqueue);
800 if (!next) {
801 rtc_alarm_disable(rtc);
802 return;
803 }
804 alarm.time = rtc_ktime_to_tm(next->expires);
805 alarm.enabled = 1;
806 err = __rtc_set_alarm(rtc, &alarm);
807 if (err == -ETIME) {
808 pm_stay_awake(rtc->dev.parent);
809 schedule_work(&rtc->irqwork);
810 }
811 }
812}
813
814/**
815 * rtc_timer_do_work - Expires rtc timers
816 * @rtc rtc device
817 * @timer timer being removed.
818 *
819 * Expires rtc timers. Reprograms next alarm event if needed.
820 * Called via worktask.
821 *
822 * Serializes access to timerqueue via ops_lock mutex
823 */
824void rtc_timer_do_work(struct work_struct *work)
825{
826 struct rtc_timer *timer;
827 struct timerqueue_node *next;
828 ktime_t now;
829 struct rtc_time tm;
830
831 struct rtc_device *rtc =
832 container_of(work, struct rtc_device, irqwork);
833
834 mutex_lock(&rtc->ops_lock);
835again:
836 __rtc_read_time(rtc, &tm);
837 now = rtc_tm_to_ktime(tm);
838 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
839 if (next->expires.tv64 > now.tv64)
840 break;
841
842 /* expire timer */
843 timer = container_of(next, struct rtc_timer, node);
844 timerqueue_del(&rtc->timerqueue, &timer->node);
845 timer->enabled = 0;
846 if (timer->task.func)
847 timer->task.func(timer->task.private_data);
848
849 /* Re-add/fwd periodic timers */
850 if (ktime_to_ns(timer->period)) {
851 timer->node.expires = ktime_add(timer->node.expires,
852 timer->period);
853 timer->enabled = 1;
854 timerqueue_add(&rtc->timerqueue, &timer->node);
855 }
856 }
857
858 /* Set next alarm */
859 if (next) {
860 struct rtc_wkalrm alarm;
861 int err;
862 int retry = 3;
863
864 alarm.time = rtc_ktime_to_tm(next->expires);
865 alarm.enabled = 1;
866reprogram:
867 err = __rtc_set_alarm(rtc, &alarm);
868 if (err == -ETIME)
869 goto again;
870 else if (err) {
871 if (retry-- > 0)
872 goto reprogram;
873
874 timer = container_of(next, struct rtc_timer, node);
875 timerqueue_del(&rtc->timerqueue, &timer->node);
876 timer->enabled = 0;
877 dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
878 goto again;
879 }
880 } else
881 rtc_alarm_disable(rtc);
882
883 pm_relax(rtc->dev.parent);
884 mutex_unlock(&rtc->ops_lock);
885}
886
887
888/* rtc_timer_init - Initializes an rtc_timer
889 * @timer: timer to be intiialized
890 * @f: function pointer to be called when timer fires
891 * @data: private data passed to function pointer
892 *
893 * Kernel interface to initializing an rtc_timer.
894 */
895void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data)
896{
897 timerqueue_init(&timer->node);
898 timer->enabled = 0;
899 timer->task.func = f;
900 timer->task.private_data = data;
901}
902
903/* rtc_timer_start - Sets an rtc_timer to fire in the future
904 * @ rtc: rtc device to be used
905 * @ timer: timer being set
906 * @ expires: time at which to expire the timer
907 * @ period: period that the timer will recur
908 *
909 * Kernel interface to set an rtc_timer
910 */
911int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
912 ktime_t expires, ktime_t period)
913{
914 int ret = 0;
915 mutex_lock(&rtc->ops_lock);
916 if (timer->enabled)
917 rtc_timer_remove(rtc, timer);
918
919 timer->node.expires = expires;
920 timer->period = period;
921
922 ret = rtc_timer_enqueue(rtc, timer);
923
924 mutex_unlock(&rtc->ops_lock);
925 return ret;
926}
927
928/* rtc_timer_cancel - Stops an rtc_timer
929 * @ rtc: rtc device to be used
930 * @ timer: timer being set
931 *
932 * Kernel interface to cancel an rtc_timer
933 */
934void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
935{
936 mutex_lock(&rtc->ops_lock);
937 if (timer->enabled)
938 rtc_timer_remove(rtc, timer);
939 mutex_unlock(&rtc->ops_lock);
940}
941
942/**
943 * rtc_read_offset - Read the amount of rtc offset in parts per billion
944 * @ rtc: rtc device to be used
945 * @ offset: the offset in parts per billion
946 *
947 * see below for details.
948 *
949 * Kernel interface to read rtc clock offset
950 * Returns 0 on success, or a negative number on error.
951 * If read_offset() is not implemented for the rtc, return -EINVAL
952 */
953int rtc_read_offset(struct rtc_device *rtc, long *offset)
954{
955 int ret;
956
957 if (!rtc->ops)
958 return -ENODEV;
959
960 if (!rtc->ops->read_offset)
961 return -EINVAL;
962
963 mutex_lock(&rtc->ops_lock);
964 ret = rtc->ops->read_offset(rtc->dev.parent, offset);
965 mutex_unlock(&rtc->ops_lock);
966 return ret;
967}
968
969/**
970 * rtc_set_offset - Adjusts the duration of the average second
971 * @ rtc: rtc device to be used
972 * @ offset: the offset in parts per billion
973 *
974 * Some rtc's allow an adjustment to the average duration of a second
975 * to compensate for differences in the actual clock rate due to temperature,
976 * the crystal, capacitor, etc.
977 *
978 * Kernel interface to adjust an rtc clock offset.
979 * Return 0 on success, or a negative number on error.
980 * If the rtc offset is not setable (or not implemented), return -EINVAL
981 */
982int rtc_set_offset(struct rtc_device *rtc, long offset)
983{
984 int ret;
985
986 if (!rtc->ops)
987 return -ENODEV;
988
989 if (!rtc->ops->set_offset)
990 return -EINVAL;
991
992 mutex_lock(&rtc->ops_lock);
993 ret = rtc->ops->set_offset(rtc->dev.parent, offset);
994 mutex_unlock(&rtc->ops_lock);
995 return ret;
996}