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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 mutex_unlock(&rtc->ops_lock);
76 /* A timer might have just expired */
77 schedule_work(&rtc->irqwork);
78 return err;
79}
80EXPORT_SYMBOL_GPL(rtc_set_time);
81
82int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
83{
84 int err;
85
86 err = mutex_lock_interruptible(&rtc->ops_lock);
87 if (err)
88 return err;
89
90 if (!rtc->ops)
91 err = -ENODEV;
92 else if (rtc->ops->set_mmss)
93 err = rtc->ops->set_mmss(rtc->dev.parent, secs);
94 else if (rtc->ops->read_time && rtc->ops->set_time) {
95 struct rtc_time new, old;
96
97 err = rtc->ops->read_time(rtc->dev.parent, &old);
98 if (err == 0) {
99 rtc_time_to_tm(secs, &new);
100
101 /*
102 * avoid writing when we're going to change the day of
103 * the month. We will retry in the next minute. This
104 * basically means that if the RTC must not drift
105 * by more than 1 minute in 11 minutes.
106 */
107 if (!((old.tm_hour == 23 && old.tm_min == 59) ||
108 (new.tm_hour == 23 && new.tm_min == 59)))
109 err = rtc->ops->set_time(rtc->dev.parent,
110 &new);
111 }
112 }
113 else
114 err = -EINVAL;
115
116 mutex_unlock(&rtc->ops_lock);
117 /* A timer might have just expired */
118 schedule_work(&rtc->irqwork);
119
120 return err;
121}
122EXPORT_SYMBOL_GPL(rtc_set_mmss);
123
124static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
125{
126 int err;
127
128 err = mutex_lock_interruptible(&rtc->ops_lock);
129 if (err)
130 return err;
131
132 if (rtc->ops == NULL)
133 err = -ENODEV;
134 else if (!rtc->ops->read_alarm)
135 err = -EINVAL;
136 else {
137 memset(alarm, 0, sizeof(struct rtc_wkalrm));
138 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
139 }
140
141 mutex_unlock(&rtc->ops_lock);
142 return err;
143}
144
145int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
146{
147 int err;
148 struct rtc_time before, now;
149 int first_time = 1;
150 unsigned long t_now, t_alm;
151 enum { none, day, month, year } missing = none;
152 unsigned days;
153
154 /* The lower level RTC driver may return -1 in some fields,
155 * creating invalid alarm->time values, for reasons like:
156 *
157 * - The hardware may not be capable of filling them in;
158 * many alarms match only on time-of-day fields, not
159 * day/month/year calendar data.
160 *
161 * - Some hardware uses illegal values as "wildcard" match
162 * values, which non-Linux firmware (like a BIOS) may try
163 * to set up as e.g. "alarm 15 minutes after each hour".
164 * Linux uses only oneshot alarms.
165 *
166 * When we see that here, we deal with it by using values from
167 * a current RTC timestamp for any missing (-1) values. The
168 * RTC driver prevents "periodic alarm" modes.
169 *
170 * But this can be racey, because some fields of the RTC timestamp
171 * may have wrapped in the interval since we read the RTC alarm,
172 * which would lead to us inserting inconsistent values in place
173 * of the -1 fields.
174 *
175 * Reading the alarm and timestamp in the reverse sequence
176 * would have the same race condition, and not solve the issue.
177 *
178 * So, we must first read the RTC timestamp,
179 * then read the RTC alarm value,
180 * and then read a second RTC timestamp.
181 *
182 * If any fields of the second timestamp have changed
183 * when compared with the first timestamp, then we know
184 * our timestamp may be inconsistent with that used by
185 * the low-level rtc_read_alarm_internal() function.
186 *
187 * So, when the two timestamps disagree, we just loop and do
188 * the process again to get a fully consistent set of values.
189 *
190 * This could all instead be done in the lower level driver,
191 * but since more than one lower level RTC implementation needs it,
192 * then it's probably best best to do it here instead of there..
193 */
194
195 /* Get the "before" timestamp */
196 err = rtc_read_time(rtc, &before);
197 if (err < 0)
198 return err;
199 do {
200 if (!first_time)
201 memcpy(&before, &now, sizeof(struct rtc_time));
202 first_time = 0;
203
204 /* get the RTC alarm values, which may be incomplete */
205 err = rtc_read_alarm_internal(rtc, alarm);
206 if (err)
207 return err;
208
209 /* full-function RTCs won't have such missing fields */
210 if (rtc_valid_tm(&alarm->time) == 0)
211 return 0;
212
213 /* get the "after" timestamp, to detect wrapped fields */
214 err = rtc_read_time(rtc, &now);
215 if (err < 0)
216 return err;
217
218 /* note that tm_sec is a "don't care" value here: */
219 } while ( before.tm_min != now.tm_min
220 || before.tm_hour != now.tm_hour
221 || before.tm_mon != now.tm_mon
222 || before.tm_year != now.tm_year);
223
224 /* Fill in the missing alarm fields using the timestamp; we
225 * know there's at least one since alarm->time is invalid.
226 */
227 if (alarm->time.tm_sec == -1)
228 alarm->time.tm_sec = now.tm_sec;
229 if (alarm->time.tm_min == -1)
230 alarm->time.tm_min = now.tm_min;
231 if (alarm->time.tm_hour == -1)
232 alarm->time.tm_hour = now.tm_hour;
233
234 /* For simplicity, only support date rollover for now */
235 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
236 alarm->time.tm_mday = now.tm_mday;
237 missing = day;
238 }
239 if ((unsigned)alarm->time.tm_mon >= 12) {
240 alarm->time.tm_mon = now.tm_mon;
241 if (missing == none)
242 missing = month;
243 }
244 if (alarm->time.tm_year == -1) {
245 alarm->time.tm_year = now.tm_year;
246 if (missing == none)
247 missing = year;
248 }
249
250 /* with luck, no rollover is needed */
251 rtc_tm_to_time(&now, &t_now);
252 rtc_tm_to_time(&alarm->time, &t_alm);
253 if (t_now < t_alm)
254 goto done;
255
256 switch (missing) {
257
258 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
259 * that will trigger at 5am will do so at 5am Tuesday, which
260 * could also be in the next month or year. This is a common
261 * case, especially for PCs.
262 */
263 case day:
264 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
265 t_alm += 24 * 60 * 60;
266 rtc_time_to_tm(t_alm, &alarm->time);
267 break;
268
269 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
270 * be next month. An alarm matching on the 30th, 29th, or 28th
271 * may end up in the month after that! Many newer PCs support
272 * this type of alarm.
273 */
274 case month:
275 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
276 do {
277 if (alarm->time.tm_mon < 11)
278 alarm->time.tm_mon++;
279 else {
280 alarm->time.tm_mon = 0;
281 alarm->time.tm_year++;
282 }
283 days = rtc_month_days(alarm->time.tm_mon,
284 alarm->time.tm_year);
285 } while (days < alarm->time.tm_mday);
286 break;
287
288 /* Year rollover ... easy except for leap years! */
289 case year:
290 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
291 do {
292 alarm->time.tm_year++;
293 } while (rtc_valid_tm(&alarm->time) != 0);
294 break;
295
296 default:
297 dev_warn(&rtc->dev, "alarm rollover not handled\n");
298 }
299
300done:
301 return 0;
302}
303
304int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
305{
306 int err;
307
308 err = mutex_lock_interruptible(&rtc->ops_lock);
309 if (err)
310 return err;
311 if (rtc->ops == NULL)
312 err = -ENODEV;
313 else if (!rtc->ops->read_alarm)
314 err = -EINVAL;
315 else {
316 memset(alarm, 0, sizeof(struct rtc_wkalrm));
317 alarm->enabled = rtc->aie_timer.enabled;
318 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
319 }
320 mutex_unlock(&rtc->ops_lock);
321
322 return err;
323}
324EXPORT_SYMBOL_GPL(rtc_read_alarm);
325
326static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
327{
328 struct rtc_time tm;
329 long now, scheduled;
330 int err;
331
332 err = rtc_valid_tm(&alarm->time);
333 if (err)
334 return err;
335 rtc_tm_to_time(&alarm->time, &scheduled);
336
337 /* Make sure we're not setting alarms in the past */
338 err = __rtc_read_time(rtc, &tm);
339 rtc_tm_to_time(&tm, &now);
340 if (scheduled <= now)
341 return -ETIME;
342 /*
343 * XXX - We just checked to make sure the alarm time is not
344 * in the past, but there is still a race window where if
345 * the is alarm set for the next second and the second ticks
346 * over right here, before we set the alarm.
347 */
348
349 if (!rtc->ops)
350 err = -ENODEV;
351 else if (!rtc->ops->set_alarm)
352 err = -EINVAL;
353 else
354 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
355
356 return err;
357}
358
359int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
360{
361 int err;
362
363 err = rtc_valid_tm(&alarm->time);
364 if (err != 0)
365 return err;
366
367 err = mutex_lock_interruptible(&rtc->ops_lock);
368 if (err)
369 return err;
370 if (rtc->aie_timer.enabled) {
371 rtc_timer_remove(rtc, &rtc->aie_timer);
372 }
373 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
374 rtc->aie_timer.period = ktime_set(0, 0);
375 if (alarm->enabled) {
376 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
377 }
378 mutex_unlock(&rtc->ops_lock);
379 return err;
380}
381EXPORT_SYMBOL_GPL(rtc_set_alarm);
382
383/* Called once per device from rtc_device_register */
384int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
385{
386 int err;
387 struct rtc_time now;
388
389 err = rtc_valid_tm(&alarm->time);
390 if (err != 0)
391 return err;
392
393 err = rtc_read_time(rtc, &now);
394 if (err)
395 return err;
396
397 err = mutex_lock_interruptible(&rtc->ops_lock);
398 if (err)
399 return err;
400
401 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
402 rtc->aie_timer.period = ktime_set(0, 0);
403
404 /* Alarm has to be enabled & in the futrure for us to enqueue it */
405 if (alarm->enabled && (rtc_tm_to_ktime(now).tv64 <
406 rtc->aie_timer.node.expires.tv64)) {
407
408 rtc->aie_timer.enabled = 1;
409 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
410 }
411 mutex_unlock(&rtc->ops_lock);
412 return err;
413}
414EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
415
416
417
418int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
419{
420 int err = mutex_lock_interruptible(&rtc->ops_lock);
421 if (err)
422 return err;
423
424 if (rtc->aie_timer.enabled != enabled) {
425 if (enabled)
426 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
427 else
428 rtc_timer_remove(rtc, &rtc->aie_timer);
429 }
430
431 if (err)
432 /* nothing */;
433 else if (!rtc->ops)
434 err = -ENODEV;
435 else if (!rtc->ops->alarm_irq_enable)
436 err = -EINVAL;
437 else
438 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
439
440 mutex_unlock(&rtc->ops_lock);
441 return err;
442}
443EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
444
445int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
446{
447 int err = mutex_lock_interruptible(&rtc->ops_lock);
448 if (err)
449 return err;
450
451#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
452 if (enabled == 0 && rtc->uie_irq_active) {
453 mutex_unlock(&rtc->ops_lock);
454 return rtc_dev_update_irq_enable_emul(rtc, 0);
455 }
456#endif
457 /* make sure we're changing state */
458 if (rtc->uie_rtctimer.enabled == enabled)
459 goto out;
460
461 if (rtc->uie_unsupported) {
462 err = -EINVAL;
463 goto out;
464 }
465
466 if (enabled) {
467 struct rtc_time tm;
468 ktime_t now, onesec;
469
470 __rtc_read_time(rtc, &tm);
471 onesec = ktime_set(1, 0);
472 now = rtc_tm_to_ktime(tm);
473 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
474 rtc->uie_rtctimer.period = ktime_set(1, 0);
475 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
476 } else
477 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
478
479out:
480 mutex_unlock(&rtc->ops_lock);
481#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
482 /*
483 * Enable emulation if the driver did not provide
484 * the update_irq_enable function pointer or if returned
485 * -EINVAL to signal that it has been configured without
486 * interrupts or that are not available at the moment.
487 */
488 if (err == -EINVAL)
489 err = rtc_dev_update_irq_enable_emul(rtc, enabled);
490#endif
491 return err;
492
493}
494EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
495
496
497/**
498 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
499 * @rtc: pointer to the rtc device
500 *
501 * This function is called when an AIE, UIE or PIE mode interrupt
502 * has occurred (or been emulated).
503 *
504 * Triggers the registered irq_task function callback.
505 */
506void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
507{
508 unsigned long flags;
509
510 /* mark one irq of the appropriate mode */
511 spin_lock_irqsave(&rtc->irq_lock, flags);
512 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
513 spin_unlock_irqrestore(&rtc->irq_lock, flags);
514
515 /* call the task func */
516 spin_lock_irqsave(&rtc->irq_task_lock, flags);
517 if (rtc->irq_task)
518 rtc->irq_task->func(rtc->irq_task->private_data);
519 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
520
521 wake_up_interruptible(&rtc->irq_queue);
522 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
523}
524
525
526/**
527 * rtc_aie_update_irq - AIE mode rtctimer hook
528 * @private: pointer to the rtc_device
529 *
530 * This functions is called when the aie_timer expires.
531 */
532void rtc_aie_update_irq(void *private)
533{
534 struct rtc_device *rtc = (struct rtc_device *)private;
535 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
536}
537
538
539/**
540 * rtc_uie_update_irq - UIE mode rtctimer hook
541 * @private: pointer to the rtc_device
542 *
543 * This functions is called when the uie_timer expires.
544 */
545void rtc_uie_update_irq(void *private)
546{
547 struct rtc_device *rtc = (struct rtc_device *)private;
548 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
549}
550
551
552/**
553 * rtc_pie_update_irq - PIE mode hrtimer hook
554 * @timer: pointer to the pie mode hrtimer
555 *
556 * This function is used to emulate PIE mode interrupts
557 * using an hrtimer. This function is called when the periodic
558 * hrtimer expires.
559 */
560enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
561{
562 struct rtc_device *rtc;
563 ktime_t period;
564 int count;
565 rtc = container_of(timer, struct rtc_device, pie_timer);
566
567 period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq);
568 count = hrtimer_forward_now(timer, period);
569
570 rtc_handle_legacy_irq(rtc, count, RTC_PF);
571
572 return HRTIMER_RESTART;
573}
574
575/**
576 * rtc_update_irq - Triggered when a RTC interrupt occurs.
577 * @rtc: the rtc device
578 * @num: how many irqs are being reported (usually one)
579 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
580 * Context: any
581 */
582void rtc_update_irq(struct rtc_device *rtc,
583 unsigned long num, unsigned long events)
584{
585 schedule_work(&rtc->irqwork);
586}
587EXPORT_SYMBOL_GPL(rtc_update_irq);
588
589static int __rtc_match(struct device *dev, void *data)
590{
591 char *name = (char *)data;
592
593 if (strcmp(dev_name(dev), name) == 0)
594 return 1;
595 return 0;
596}
597
598struct rtc_device *rtc_class_open(char *name)
599{
600 struct device *dev;
601 struct rtc_device *rtc = NULL;
602
603 dev = class_find_device(rtc_class, NULL, name, __rtc_match);
604 if (dev)
605 rtc = to_rtc_device(dev);
606
607 if (rtc) {
608 if (!try_module_get(rtc->owner)) {
609 put_device(dev);
610 rtc = NULL;
611 }
612 }
613
614 return rtc;
615}
616EXPORT_SYMBOL_GPL(rtc_class_open);
617
618void rtc_class_close(struct rtc_device *rtc)
619{
620 module_put(rtc->owner);
621 put_device(&rtc->dev);
622}
623EXPORT_SYMBOL_GPL(rtc_class_close);
624
625int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
626{
627 int retval = -EBUSY;
628
629 if (task == NULL || task->func == NULL)
630 return -EINVAL;
631
632 /* Cannot register while the char dev is in use */
633 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
634 return -EBUSY;
635
636 spin_lock_irq(&rtc->irq_task_lock);
637 if (rtc->irq_task == NULL) {
638 rtc->irq_task = task;
639 retval = 0;
640 }
641 spin_unlock_irq(&rtc->irq_task_lock);
642
643 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
644
645 return retval;
646}
647EXPORT_SYMBOL_GPL(rtc_irq_register);
648
649void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
650{
651 spin_lock_irq(&rtc->irq_task_lock);
652 if (rtc->irq_task == task)
653 rtc->irq_task = NULL;
654 spin_unlock_irq(&rtc->irq_task_lock);
655}
656EXPORT_SYMBOL_GPL(rtc_irq_unregister);
657
658static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
659{
660 /*
661 * We always cancel the timer here first, because otherwise
662 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
663 * when we manage to start the timer before the callback
664 * returns HRTIMER_RESTART.
665 *
666 * We cannot use hrtimer_cancel() here as a running callback
667 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
668 * would spin forever.
669 */
670 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
671 return -1;
672
673 if (enabled) {
674 ktime_t period = ktime_set(0, NSEC_PER_SEC / rtc->irq_freq);
675
676 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
677 }
678 return 0;
679}
680
681/**
682 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
683 * @rtc: the rtc device
684 * @task: currently registered with rtc_irq_register()
685 * @enabled: true to enable periodic IRQs
686 * Context: any
687 *
688 * Note that rtc_irq_set_freq() should previously have been used to
689 * specify the desired frequency of periodic IRQ task->func() callbacks.
690 */
691int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
692{
693 int err = 0;
694 unsigned long flags;
695
696retry:
697 spin_lock_irqsave(&rtc->irq_task_lock, flags);
698 if (rtc->irq_task != NULL && task == NULL)
699 err = -EBUSY;
700 if (rtc->irq_task != task)
701 err = -EACCES;
702 if (!err) {
703 if (rtc_update_hrtimer(rtc, enabled) < 0) {
704 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
705 cpu_relax();
706 goto retry;
707 }
708 rtc->pie_enabled = enabled;
709 }
710 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
711 return err;
712}
713EXPORT_SYMBOL_GPL(rtc_irq_set_state);
714
715/**
716 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
717 * @rtc: the rtc device
718 * @task: currently registered with rtc_irq_register()
719 * @freq: positive frequency with which task->func() will be called
720 * Context: any
721 *
722 * Note that rtc_irq_set_state() is used to enable or disable the
723 * periodic IRQs.
724 */
725int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
726{
727 int err = 0;
728 unsigned long flags;
729
730 if (freq <= 0 || freq > RTC_MAX_FREQ)
731 return -EINVAL;
732retry:
733 spin_lock_irqsave(&rtc->irq_task_lock, flags);
734 if (rtc->irq_task != NULL && task == NULL)
735 err = -EBUSY;
736 if (rtc->irq_task != task)
737 err = -EACCES;
738 if (!err) {
739 rtc->irq_freq = freq;
740 if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) {
741 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
742 cpu_relax();
743 goto retry;
744 }
745 }
746 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
747 return err;
748}
749EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
750
751/**
752 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
753 * @rtc rtc device
754 * @timer timer being added.
755 *
756 * Enqueues a timer onto the rtc devices timerqueue and sets
757 * the next alarm event appropriately.
758 *
759 * Sets the enabled bit on the added timer.
760 *
761 * Must hold ops_lock for proper serialization of timerqueue
762 */
763static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
764{
765 timer->enabled = 1;
766 timerqueue_add(&rtc->timerqueue, &timer->node);
767 if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) {
768 struct rtc_wkalrm alarm;
769 int err;
770 alarm.time = rtc_ktime_to_tm(timer->node.expires);
771 alarm.enabled = 1;
772 err = __rtc_set_alarm(rtc, &alarm);
773 if (err == -ETIME)
774 schedule_work(&rtc->irqwork);
775 else if (err) {
776 timerqueue_del(&rtc->timerqueue, &timer->node);
777 timer->enabled = 0;
778 return err;
779 }
780 }
781 return 0;
782}
783
784static void rtc_alarm_disable(struct rtc_device *rtc)
785{
786 if (!rtc->ops || !rtc->ops->alarm_irq_enable)
787 return;
788
789 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
790}
791
792/**
793 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
794 * @rtc rtc device
795 * @timer timer being removed.
796 *
797 * Removes a timer onto the rtc devices timerqueue and sets
798 * the next alarm event appropriately.
799 *
800 * Clears the enabled bit on the removed timer.
801 *
802 * Must hold ops_lock for proper serialization of timerqueue
803 */
804static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
805{
806 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
807 timerqueue_del(&rtc->timerqueue, &timer->node);
808 timer->enabled = 0;
809 if (next == &timer->node) {
810 struct rtc_wkalrm alarm;
811 int err;
812 next = timerqueue_getnext(&rtc->timerqueue);
813 if (!next) {
814 rtc_alarm_disable(rtc);
815 return;
816 }
817 alarm.time = rtc_ktime_to_tm(next->expires);
818 alarm.enabled = 1;
819 err = __rtc_set_alarm(rtc, &alarm);
820 if (err == -ETIME)
821 schedule_work(&rtc->irqwork);
822 }
823}
824
825/**
826 * rtc_timer_do_work - Expires rtc timers
827 * @rtc rtc device
828 * @timer timer being removed.
829 *
830 * Expires rtc timers. Reprograms next alarm event if needed.
831 * Called via worktask.
832 *
833 * Serializes access to timerqueue via ops_lock mutex
834 */
835void rtc_timer_do_work(struct work_struct *work)
836{
837 struct rtc_timer *timer;
838 struct timerqueue_node *next;
839 ktime_t now;
840 struct rtc_time tm;
841
842 struct rtc_device *rtc =
843 container_of(work, struct rtc_device, irqwork);
844
845 mutex_lock(&rtc->ops_lock);
846again:
847 __rtc_read_time(rtc, &tm);
848 now = rtc_tm_to_ktime(tm);
849 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
850 if (next->expires.tv64 > now.tv64)
851 break;
852
853 /* expire timer */
854 timer = container_of(next, struct rtc_timer, node);
855 timerqueue_del(&rtc->timerqueue, &timer->node);
856 timer->enabled = 0;
857 if (timer->task.func)
858 timer->task.func(timer->task.private_data);
859
860 /* Re-add/fwd periodic timers */
861 if (ktime_to_ns(timer->period)) {
862 timer->node.expires = ktime_add(timer->node.expires,
863 timer->period);
864 timer->enabled = 1;
865 timerqueue_add(&rtc->timerqueue, &timer->node);
866 }
867 }
868
869 /* Set next alarm */
870 if (next) {
871 struct rtc_wkalrm alarm;
872 int err;
873 alarm.time = rtc_ktime_to_tm(next->expires);
874 alarm.enabled = 1;
875 err = __rtc_set_alarm(rtc, &alarm);
876 if (err == -ETIME)
877 goto again;
878 } else
879 rtc_alarm_disable(rtc);
880
881 mutex_unlock(&rtc->ops_lock);
882}
883
884
885/* rtc_timer_init - Initializes an rtc_timer
886 * @timer: timer to be intiialized
887 * @f: function pointer to be called when timer fires
888 * @data: private data passed to function pointer
889 *
890 * Kernel interface to initializing an rtc_timer.
891 */
892void rtc_timer_init(struct rtc_timer *timer, void (*f)(void* p), void* data)
893{
894 timerqueue_init(&timer->node);
895 timer->enabled = 0;
896 timer->task.func = f;
897 timer->task.private_data = data;
898}
899
900/* rtc_timer_start - Sets an rtc_timer to fire in the future
901 * @ rtc: rtc device to be used
902 * @ timer: timer being set
903 * @ expires: time at which to expire the timer
904 * @ period: period that the timer will recur
905 *
906 * Kernel interface to set an rtc_timer
907 */
908int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer* timer,
909 ktime_t expires, ktime_t period)
910{
911 int ret = 0;
912 mutex_lock(&rtc->ops_lock);
913 if (timer->enabled)
914 rtc_timer_remove(rtc, timer);
915
916 timer->node.expires = expires;
917 timer->period = period;
918
919 ret = rtc_timer_enqueue(rtc, timer);
920
921 mutex_unlock(&rtc->ops_lock);
922 return ret;
923}
924
925/* rtc_timer_cancel - Stops an rtc_timer
926 * @ rtc: rtc device to be used
927 * @ timer: timer being set
928 *
929 * Kernel interface to cancel an rtc_timer
930 */
931int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer* timer)
932{
933 int ret = 0;
934 mutex_lock(&rtc->ops_lock);
935 if (timer->enabled)
936 rtc_timer_remove(rtc, timer);
937 mutex_unlock(&rtc->ops_lock);
938 return ret;
939}
940
941