projects/linux·blob v4.18 · refs

1143 lines · 28.3 KiB

1/*
2 * RTC subsystem, interface functions
3 *
4 * Copyright (C) 2005 Tower Technologies
5 * Author: Alessandro Zummo <[email protected]>
6 *
7 * based on arch/arm/common/rtctime.c
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12*/
13
14#include <linux/rtc.h>
15#include <linux/sched.h>
16#include <linux/module.h>
17#include <linux/log2.h>
18#include <linux/workqueue.h>
19
20#define CREATE_TRACE_POINTS
21#include <trace/events/rtc.h>
22
23static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);
24static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer);
25
26static void rtc_add_offset(struct rtc_device *rtc, struct rtc_time *tm)
27{
28 time64_t secs;
29
30 if (!rtc->offset_secs)
31 return;
32
33 secs = rtc_tm_to_time64(tm);
34
35 /*
36 * Since the reading time values from RTC device are always in the RTC
37 * original valid range, but we need to skip the overlapped region
38 * between expanded range and original range, which is no need to add
39 * the offset.
40 */
41 if ((rtc->start_secs > rtc->range_min && secs >= rtc->start_secs) ||
42 (rtc->start_secs < rtc->range_min &&
43 secs <= (rtc->start_secs + rtc->range_max - rtc->range_min)))
44 return;
45
46 rtc_time64_to_tm(secs + rtc->offset_secs, tm);
47}
48
49static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm)
50{
51 time64_t secs;
52
53 if (!rtc->offset_secs)
54 return;
55
56 secs = rtc_tm_to_time64(tm);
57
58 /*
59 * If the setting time values are in the valid range of RTC hardware
60 * device, then no need to subtract the offset when setting time to RTC
61 * device. Otherwise we need to subtract the offset to make the time
62 * values are valid for RTC hardware device.
63 */
64 if (secs >= rtc->range_min && secs <= rtc->range_max)
65 return;
66
67 rtc_time64_to_tm(secs - rtc->offset_secs, tm);
68}
69
70static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm)
71{
72 if (rtc->range_min != rtc->range_max) {
73 time64_t time = rtc_tm_to_time64(tm);
74 time64_t range_min = rtc->set_start_time ? rtc->start_secs :
75 rtc->range_min;
76 time64_t range_max = rtc->set_start_time ?
77 (rtc->start_secs + rtc->range_max - rtc->range_min) :
78 rtc->range_max;
79
80 if (time < range_min || time > range_max)
81 return -ERANGE;
82 }
83
84 return 0;
85}
86
87static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
88{
89 int err;
90 if (!rtc->ops)
91 err = -ENODEV;
92 else if (!rtc->ops->read_time)
93 err = -EINVAL;
94 else {
95 memset(tm, 0, sizeof(struct rtc_time));
96 err = rtc->ops->read_time(rtc->dev.parent, tm);
97 if (err < 0) {
98 dev_dbg(&rtc->dev, "read_time: fail to read: %d\n",
99 err);
100 return err;
101 }
102
103 rtc_add_offset(rtc, tm);
104
105 err = rtc_valid_tm(tm);
106 if (err < 0)
107 dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n");
108 }
109 return err;
110}
111
112int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
113{
114 int err;
115
116 err = mutex_lock_interruptible(&rtc->ops_lock);
117 if (err)
118 return err;
119
120 err = __rtc_read_time(rtc, tm);
121 mutex_unlock(&rtc->ops_lock);
122
123 trace_rtc_read_time(rtc_tm_to_time64(tm), err);
124 return err;
125}
126EXPORT_SYMBOL_GPL(rtc_read_time);
127
128int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
129{
130 int err;
131
132 err = rtc_valid_tm(tm);
133 if (err != 0)
134 return err;
135
136 err = rtc_valid_range(rtc, tm);
137 if (err)
138 return err;
139
140 rtc_subtract_offset(rtc, tm);
141
142 err = mutex_lock_interruptible(&rtc->ops_lock);
143 if (err)
144 return err;
145
146 if (!rtc->ops)
147 err = -ENODEV;
148 else if (rtc->ops->set_time)
149 err = rtc->ops->set_time(rtc->dev.parent, tm);
150 else if (rtc->ops->set_mmss64) {
151 time64_t secs64 = rtc_tm_to_time64(tm);
152
153 err = rtc->ops->set_mmss64(rtc->dev.parent, secs64);
154 } else if (rtc->ops->set_mmss) {
155 time64_t secs64 = rtc_tm_to_time64(tm);
156 err = rtc->ops->set_mmss(rtc->dev.parent, secs64);
157 } else
158 err = -EINVAL;
159
160 pm_stay_awake(rtc->dev.parent);
161 mutex_unlock(&rtc->ops_lock);
162 /* A timer might have just expired */
163 schedule_work(&rtc->irqwork);
164
165 trace_rtc_set_time(rtc_tm_to_time64(tm), err);
166 return err;
167}
168EXPORT_SYMBOL_GPL(rtc_set_time);
169
170static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
171{
172 int err;
173
174 err = mutex_lock_interruptible(&rtc->ops_lock);
175 if (err)
176 return err;
177
178 if (rtc->ops == NULL)
179 err = -ENODEV;
180 else if (!rtc->ops->read_alarm)
181 err = -EINVAL;
182 else {
183 alarm->enabled = 0;
184 alarm->pending = 0;
185 alarm->time.tm_sec = -1;
186 alarm->time.tm_min = -1;
187 alarm->time.tm_hour = -1;
188 alarm->time.tm_mday = -1;
189 alarm->time.tm_mon = -1;
190 alarm->time.tm_year = -1;
191 alarm->time.tm_wday = -1;
192 alarm->time.tm_yday = -1;
193 alarm->time.tm_isdst = -1;
194 err = rtc->ops->read_alarm(rtc->dev.parent, alarm);
195 }
196
197 mutex_unlock(&rtc->ops_lock);
198
199 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
200 return err;
201}
202
203int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
204{
205 int err;
206 struct rtc_time before, now;
207 int first_time = 1;
208 time64_t t_now, t_alm;
209 enum { none, day, month, year } missing = none;
210 unsigned days;
211
212 /* The lower level RTC driver may return -1 in some fields,
213 * creating invalid alarm->time values, for reasons like:
214 *
215 * - The hardware may not be capable of filling them in;
216 * many alarms match only on time-of-day fields, not
217 * day/month/year calendar data.
218 *
219 * - Some hardware uses illegal values as "wildcard" match
220 * values, which non-Linux firmware (like a BIOS) may try
221 * to set up as e.g. "alarm 15 minutes after each hour".
222 * Linux uses only oneshot alarms.
223 *
224 * When we see that here, we deal with it by using values from
225 * a current RTC timestamp for any missing (-1) values. The
226 * RTC driver prevents "periodic alarm" modes.
227 *
228 * But this can be racey, because some fields of the RTC timestamp
229 * may have wrapped in the interval since we read the RTC alarm,
230 * which would lead to us inserting inconsistent values in place
231 * of the -1 fields.
232 *
233 * Reading the alarm and timestamp in the reverse sequence
234 * would have the same race condition, and not solve the issue.
235 *
236 * So, we must first read the RTC timestamp,
237 * then read the RTC alarm value,
238 * and then read a second RTC timestamp.
239 *
240 * If any fields of the second timestamp have changed
241 * when compared with the first timestamp, then we know
242 * our timestamp may be inconsistent with that used by
243 * the low-level rtc_read_alarm_internal() function.
244 *
245 * So, when the two timestamps disagree, we just loop and do
246 * the process again to get a fully consistent set of values.
247 *
248 * This could all instead be done in the lower level driver,
249 * but since more than one lower level RTC implementation needs it,
250 * then it's probably best best to do it here instead of there..
251 */
252
253 /* Get the "before" timestamp */
254 err = rtc_read_time(rtc, &before);
255 if (err < 0)
256 return err;
257 do {
258 if (!first_time)
259 memcpy(&before, &now, sizeof(struct rtc_time));
260 first_time = 0;
261
262 /* get the RTC alarm values, which may be incomplete */
263 err = rtc_read_alarm_internal(rtc, alarm);
264 if (err)
265 return err;
266
267 /* full-function RTCs won't have such missing fields */
268 if (rtc_valid_tm(&alarm->time) == 0) {
269 rtc_add_offset(rtc, &alarm->time);
270 return 0;
271 }
272
273 /* get the "after" timestamp, to detect wrapped fields */
274 err = rtc_read_time(rtc, &now);
275 if (err < 0)
276 return err;
277
278 /* note that tm_sec is a "don't care" value here: */
279 } while ( before.tm_min != now.tm_min
280 || before.tm_hour != now.tm_hour
281 || before.tm_mon != now.tm_mon
282 || before.tm_year != now.tm_year);
283
284 /* Fill in the missing alarm fields using the timestamp; we
285 * know there's at least one since alarm->time is invalid.
286 */
287 if (alarm->time.tm_sec == -1)
288 alarm->time.tm_sec = now.tm_sec;
289 if (alarm->time.tm_min == -1)
290 alarm->time.tm_min = now.tm_min;
291 if (alarm->time.tm_hour == -1)
292 alarm->time.tm_hour = now.tm_hour;
293
294 /* For simplicity, only support date rollover for now */
295 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {
296 alarm->time.tm_mday = now.tm_mday;
297 missing = day;
298 }
299 if ((unsigned)alarm->time.tm_mon >= 12) {
300 alarm->time.tm_mon = now.tm_mon;
301 if (missing == none)
302 missing = month;
303 }
304 if (alarm->time.tm_year == -1) {
305 alarm->time.tm_year = now.tm_year;
306 if (missing == none)
307 missing = year;
308 }
309
310 /* Can't proceed if alarm is still invalid after replacing
311 * missing fields.
312 */
313 err = rtc_valid_tm(&alarm->time);
314 if (err)
315 goto done;
316
317 /* with luck, no rollover is needed */
318 t_now = rtc_tm_to_time64(&now);
319 t_alm = rtc_tm_to_time64(&alarm->time);
320 if (t_now < t_alm)
321 goto done;
322
323 switch (missing) {
324
325 /* 24 hour rollover ... if it's now 10am Monday, an alarm that
326 * that will trigger at 5am will do so at 5am Tuesday, which
327 * could also be in the next month or year. This is a common
328 * case, especially for PCs.
329 */
330 case day:
331 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");
332 t_alm += 24 * 60 * 60;
333 rtc_time64_to_tm(t_alm, &alarm->time);
334 break;
335
336 /* Month rollover ... if it's the 31th, an alarm on the 3rd will
337 * be next month. An alarm matching on the 30th, 29th, or 28th
338 * may end up in the month after that! Many newer PCs support
339 * this type of alarm.
340 */
341 case month:
342 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");
343 do {
344 if (alarm->time.tm_mon < 11)
345 alarm->time.tm_mon++;
346 else {
347 alarm->time.tm_mon = 0;
348 alarm->time.tm_year++;
349 }
350 days = rtc_month_days(alarm->time.tm_mon,
351 alarm->time.tm_year);
352 } while (days < alarm->time.tm_mday);
353 break;
354
355 /* Year rollover ... easy except for leap years! */
356 case year:
357 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");
358 do {
359 alarm->time.tm_year++;
360 } while (!is_leap_year(alarm->time.tm_year + 1900)
361 && rtc_valid_tm(&alarm->time) != 0);
362 break;
363
364 default:
365 dev_warn(&rtc->dev, "alarm rollover not handled\n");
366 }
367
368 err = rtc_valid_tm(&alarm->time);
369
370done:
371 if (err) {
372 dev_warn(&rtc->dev, "invalid alarm value: %d-%d-%d %d:%d:%d\n",
373 alarm->time.tm_year + 1900, alarm->time.tm_mon + 1,
374 alarm->time.tm_mday, alarm->time.tm_hour, alarm->time.tm_min,
375 alarm->time.tm_sec);
376 }
377
378 return err;
379}
380
381int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
382{
383 int err;
384
385 err = mutex_lock_interruptible(&rtc->ops_lock);
386 if (err)
387 return err;
388 if (rtc->ops == NULL)
389 err = -ENODEV;
390 else if (!rtc->ops->read_alarm)
391 err = -EINVAL;
392 else {
393 memset(alarm, 0, sizeof(struct rtc_wkalrm));
394 alarm->enabled = rtc->aie_timer.enabled;
395 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);
396 }
397 mutex_unlock(&rtc->ops_lock);
398
399 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err);
400 return err;
401}
402EXPORT_SYMBOL_GPL(rtc_read_alarm);
403
404static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
405{
406 struct rtc_time tm;
407 time64_t now, scheduled;
408 int err;
409
410 err = rtc_valid_tm(&alarm->time);
411 if (err)
412 return err;
413
414 scheduled = rtc_tm_to_time64(&alarm->time);
415
416 /* Make sure we're not setting alarms in the past */
417 err = __rtc_read_time(rtc, &tm);
418 if (err)
419 return err;
420 now = rtc_tm_to_time64(&tm);
421 if (scheduled <= now)
422 return -ETIME;
423 /*
424 * XXX - We just checked to make sure the alarm time is not
425 * in the past, but there is still a race window where if
426 * the is alarm set for the next second and the second ticks
427 * over right here, before we set the alarm.
428 */
429
430 rtc_subtract_offset(rtc, &alarm->time);
431
432 if (!rtc->ops)
433 err = -ENODEV;
434 else if (!rtc->ops->set_alarm)
435 err = -EINVAL;
436 else
437 err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
438
439 trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
440 return err;
441}
442
443int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
444{
445 int err;
446
447 if (!rtc->ops)
448 return -ENODEV;
449 else if (!rtc->ops->set_alarm)
450 return -EINVAL;
451
452 err = rtc_valid_tm(&alarm->time);
453 if (err != 0)
454 return err;
455
456 err = rtc_valid_range(rtc, &alarm->time);
457 if (err)
458 return err;
459
460 err = mutex_lock_interruptible(&rtc->ops_lock);
461 if (err)
462 return err;
463 if (rtc->aie_timer.enabled)
464 rtc_timer_remove(rtc, &rtc->aie_timer);
465
466 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
467 rtc->aie_timer.period = 0;
468 if (alarm->enabled)
469 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
470
471 mutex_unlock(&rtc->ops_lock);
472
473 return err;
474}
475EXPORT_SYMBOL_GPL(rtc_set_alarm);
476
477/* Called once per device from rtc_device_register */
478int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
479{
480 int err;
481 struct rtc_time now;
482
483 err = rtc_valid_tm(&alarm->time);
484 if (err != 0)
485 return err;
486
487 err = rtc_read_time(rtc, &now);
488 if (err)
489 return err;
490
491 err = mutex_lock_interruptible(&rtc->ops_lock);
492 if (err)
493 return err;
494
495 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);
496 rtc->aie_timer.period = 0;
497
498 /* Alarm has to be enabled & in the future for us to enqueue it */
499 if (alarm->enabled && (rtc_tm_to_ktime(now) <
500 rtc->aie_timer.node.expires)) {
501
502 rtc->aie_timer.enabled = 1;
503 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
504 trace_rtc_timer_enqueue(&rtc->aie_timer);
505 }
506 mutex_unlock(&rtc->ops_lock);
507 return err;
508}
509EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
510
511int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
512{
513 int err = mutex_lock_interruptible(&rtc->ops_lock);
514 if (err)
515 return err;
516
517 if (rtc->aie_timer.enabled != enabled) {
518 if (enabled)
519 err = rtc_timer_enqueue(rtc, &rtc->aie_timer);
520 else
521 rtc_timer_remove(rtc, &rtc->aie_timer);
522 }
523
524 if (err)
525 /* nothing */;
526 else if (!rtc->ops)
527 err = -ENODEV;
528 else if (!rtc->ops->alarm_irq_enable)
529 err = -EINVAL;
530 else
531 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
532
533 mutex_unlock(&rtc->ops_lock);
534
535 trace_rtc_alarm_irq_enable(enabled, err);
536 return err;
537}
538EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
539
540int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
541{
542 int err = mutex_lock_interruptible(&rtc->ops_lock);
543 if (err)
544 return err;
545
546#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
547 if (enabled == 0 && rtc->uie_irq_active) {
548 mutex_unlock(&rtc->ops_lock);
549 return rtc_dev_update_irq_enable_emul(rtc, 0);
550 }
551#endif
552 /* make sure we're changing state */
553 if (rtc->uie_rtctimer.enabled == enabled)
554 goto out;
555
556 if (rtc->uie_unsupported) {
557 err = -EINVAL;
558 goto out;
559 }
560
561 if (enabled) {
562 struct rtc_time tm;
563 ktime_t now, onesec;
564
565 __rtc_read_time(rtc, &tm);
566 onesec = ktime_set(1, 0);
567 now = rtc_tm_to_ktime(tm);
568 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
569 rtc->uie_rtctimer.period = ktime_set(1, 0);
570 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
571 } else
572 rtc_timer_remove(rtc, &rtc->uie_rtctimer);
573
574out:
575 mutex_unlock(&rtc->ops_lock);
576#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
577 /*
578 * Enable emulation if the driver did not provide
579 * the update_irq_enable function pointer or if returned
580 * -EINVAL to signal that it has been configured without
581 * interrupts or that are not available at the moment.
582 */
583 if (err == -EINVAL)
584 err = rtc_dev_update_irq_enable_emul(rtc, enabled);
585#endif
586 return err;
587
588}
589EXPORT_SYMBOL_GPL(rtc_update_irq_enable);
590
591
592/**
593 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook
594 * @rtc: pointer to the rtc device
595 *
596 * This function is called when an AIE, UIE or PIE mode interrupt
597 * has occurred (or been emulated).
598 *
599 * Triggers the registered irq_task function callback.
600 */
601void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
602{
603 unsigned long flags;
604
605 /* mark one irq of the appropriate mode */
606 spin_lock_irqsave(&rtc->irq_lock, flags);
607 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode);
608 spin_unlock_irqrestore(&rtc->irq_lock, flags);
609
610 /* call the task func */
611 spin_lock_irqsave(&rtc->irq_task_lock, flags);
612 if (rtc->irq_task)
613 rtc->irq_task->func(rtc->irq_task->private_data);
614 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
615
616 wake_up_interruptible(&rtc->irq_queue);
617 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
618}
619
620
621/**
622 * rtc_aie_update_irq - AIE mode rtctimer hook
623 * @private: pointer to the rtc_device
624 *
625 * This functions is called when the aie_timer expires.
626 */
627void rtc_aie_update_irq(void *private)
628{
629 struct rtc_device *rtc = (struct rtc_device *)private;
630 rtc_handle_legacy_irq(rtc, 1, RTC_AF);
631}
632
633
634/**
635 * rtc_uie_update_irq - UIE mode rtctimer hook
636 * @private: pointer to the rtc_device
637 *
638 * This functions is called when the uie_timer expires.
639 */
640void rtc_uie_update_irq(void *private)
641{
642 struct rtc_device *rtc = (struct rtc_device *)private;
643 rtc_handle_legacy_irq(rtc, 1, RTC_UF);
644}
645
646
647/**
648 * rtc_pie_update_irq - PIE mode hrtimer hook
649 * @timer: pointer to the pie mode hrtimer
650 *
651 * This function is used to emulate PIE mode interrupts
652 * using an hrtimer. This function is called when the periodic
653 * hrtimer expires.
654 */
655enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
656{
657 struct rtc_device *rtc;
658 ktime_t period;
659 int count;
660 rtc = container_of(timer, struct rtc_device, pie_timer);
661
662 period = NSEC_PER_SEC / rtc->irq_freq;
663 count = hrtimer_forward_now(timer, period);
664
665 rtc_handle_legacy_irq(rtc, count, RTC_PF);
666
667 return HRTIMER_RESTART;
668}
669
670/**
671 * rtc_update_irq - Triggered when a RTC interrupt occurs.
672 * @rtc: the rtc device
673 * @num: how many irqs are being reported (usually one)
674 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
675 * Context: any
676 */
677void rtc_update_irq(struct rtc_device *rtc,
678 unsigned long num, unsigned long events)
679{
680 if (IS_ERR_OR_NULL(rtc))
681 return;
682
683 pm_stay_awake(rtc->dev.parent);
684 schedule_work(&rtc->irqwork);
685}
686EXPORT_SYMBOL_GPL(rtc_update_irq);
687
688static int __rtc_match(struct device *dev, const void *data)
689{
690 const char *name = data;
691
692 if (strcmp(dev_name(dev), name) == 0)
693 return 1;
694 return 0;
695}
696
697struct rtc_device *rtc_class_open(const char *name)
698{
699 struct device *dev;
700 struct rtc_device *rtc = NULL;
701
702 dev = class_find_device(rtc_class, NULL, name, __rtc_match);
703 if (dev)
704 rtc = to_rtc_device(dev);
705
706 if (rtc) {
707 if (!try_module_get(rtc->owner)) {
708 put_device(dev);
709 rtc = NULL;
710 }
711 }
712
713 return rtc;
714}
715EXPORT_SYMBOL_GPL(rtc_class_open);
716
717void rtc_class_close(struct rtc_device *rtc)
718{
719 module_put(rtc->owner);
720 put_device(&rtc->dev);
721}
722EXPORT_SYMBOL_GPL(rtc_class_close);
723
724int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
725{
726 int retval = -EBUSY;
727
728 if (task == NULL || task->func == NULL)
729 return -EINVAL;
730
731 /* Cannot register while the char dev is in use */
732 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
733 return -EBUSY;
734
735 spin_lock_irq(&rtc->irq_task_lock);
736 if (rtc->irq_task == NULL) {
737 rtc->irq_task = task;
738 retval = 0;
739 }
740 spin_unlock_irq(&rtc->irq_task_lock);
741
742 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
743
744 return retval;
745}
746EXPORT_SYMBOL_GPL(rtc_irq_register);
747
748void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
749{
750 spin_lock_irq(&rtc->irq_task_lock);
751 if (rtc->irq_task == task)
752 rtc->irq_task = NULL;
753 spin_unlock_irq(&rtc->irq_task_lock);
754}
755EXPORT_SYMBOL_GPL(rtc_irq_unregister);
756
757static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
758{
759 /*
760 * We always cancel the timer here first, because otherwise
761 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK);
762 * when we manage to start the timer before the callback
763 * returns HRTIMER_RESTART.
764 *
765 * We cannot use hrtimer_cancel() here as a running callback
766 * could be blocked on rtc->irq_task_lock and hrtimer_cancel()
767 * would spin forever.
768 */
769 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0)
770 return -1;
771
772 if (enabled) {
773 ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
774
775 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL);
776 }
777 return 0;
778}
779
780/**
781 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
782 * @rtc: the rtc device
783 * @task: currently registered with rtc_irq_register()
784 * @enabled: true to enable periodic IRQs
785 * Context: any
786 *
787 * Note that rtc_irq_set_freq() should previously have been used to
788 * specify the desired frequency of periodic IRQ task->func() callbacks.
789 */
790int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled)
791{
792 int err = 0;
793 unsigned long flags;
794
795retry:
796 spin_lock_irqsave(&rtc->irq_task_lock, flags);
797 if (rtc->irq_task != NULL && task == NULL)
798 err = -EBUSY;
799 else if (rtc->irq_task != task)
800 err = -EACCES;
801 else {
802 if (rtc_update_hrtimer(rtc, enabled) < 0) {
803 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
804 cpu_relax();
805 goto retry;
806 }
807 rtc->pie_enabled = enabled;
808 }
809 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
810
811 trace_rtc_irq_set_state(enabled, err);
812 return err;
813}
814EXPORT_SYMBOL_GPL(rtc_irq_set_state);
815
816/**
817 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
818 * @rtc: the rtc device
819 * @task: currently registered with rtc_irq_register()
820 * @freq: positive frequency with which task->func() will be called
821 * Context: any
822 *
823 * Note that rtc_irq_set_state() is used to enable or disable the
824 * periodic IRQs.
825 */
826int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq)
827{
828 int err = 0;
829 unsigned long flags;
830
831 if (freq <= 0 || freq > RTC_MAX_FREQ)
832 return -EINVAL;
833retry:
834 spin_lock_irqsave(&rtc->irq_task_lock, flags);
835 if (rtc->irq_task != NULL && task == NULL)
836 err = -EBUSY;
837 else if (rtc->irq_task != task)
838 err = -EACCES;
839 else {
840 rtc->irq_freq = freq;
841 if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) {
842 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
843 cpu_relax();
844 goto retry;
845 }
846 }
847 spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
848
849 trace_rtc_irq_set_freq(freq, err);
850 return err;
851}
852EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
853
854/**
855 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue
856 * @rtc rtc device
857 * @timer timer being added.
858 *
859 * Enqueues a timer onto the rtc devices timerqueue and sets
860 * the next alarm event appropriately.
861 *
862 * Sets the enabled bit on the added timer.
863 *
864 * Must hold ops_lock for proper serialization of timerqueue
865 */
866static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
867{
868 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
869 struct rtc_time tm;
870 ktime_t now;
871
872 timer->enabled = 1;
873 __rtc_read_time(rtc, &tm);
874 now = rtc_tm_to_ktime(tm);
875
876 /* Skip over expired timers */
877 while (next) {
878 if (next->expires >= now)
879 break;
880 next = timerqueue_iterate_next(next);
881 }
882
883 timerqueue_add(&rtc->timerqueue, &timer->node);
884 trace_rtc_timer_enqueue(timer);
885 if (!next || ktime_before(timer->node.expires, next->expires)) {
886 struct rtc_wkalrm alarm;
887 int err;
888 alarm.time = rtc_ktime_to_tm(timer->node.expires);
889 alarm.enabled = 1;
890 err = __rtc_set_alarm(rtc, &alarm);
891 if (err == -ETIME) {
892 pm_stay_awake(rtc->dev.parent);
893 schedule_work(&rtc->irqwork);
894 } else if (err) {
895 timerqueue_del(&rtc->timerqueue, &timer->node);
896 trace_rtc_timer_dequeue(timer);
897 timer->enabled = 0;
898 return err;
899 }
900 }
901 return 0;
902}
903
904static void rtc_alarm_disable(struct rtc_device *rtc)
905{
906 if (!rtc->ops || !rtc->ops->alarm_irq_enable)
907 return;
908
909 rtc->ops->alarm_irq_enable(rtc->dev.parent, false);
910 trace_rtc_alarm_irq_enable(0, 0);
911}
912
913/**
914 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue
915 * @rtc rtc device
916 * @timer timer being removed.
917 *
918 * Removes a timer onto the rtc devices timerqueue and sets
919 * the next alarm event appropriately.
920 *
921 * Clears the enabled bit on the removed timer.
922 *
923 * Must hold ops_lock for proper serialization of timerqueue
924 */
925static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
926{
927 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
928 timerqueue_del(&rtc->timerqueue, &timer->node);
929 trace_rtc_timer_dequeue(timer);
930 timer->enabled = 0;
931 if (next == &timer->node) {
932 struct rtc_wkalrm alarm;
933 int err;
934 next = timerqueue_getnext(&rtc->timerqueue);
935 if (!next) {
936 rtc_alarm_disable(rtc);
937 return;
938 }
939 alarm.time = rtc_ktime_to_tm(next->expires);
940 alarm.enabled = 1;
941 err = __rtc_set_alarm(rtc, &alarm);
942 if (err == -ETIME) {
943 pm_stay_awake(rtc->dev.parent);
944 schedule_work(&rtc->irqwork);
945 }
946 }
947}
948
949/**
950 * rtc_timer_do_work - Expires rtc timers
951 * @rtc rtc device
952 * @timer timer being removed.
953 *
954 * Expires rtc timers. Reprograms next alarm event if needed.
955 * Called via worktask.
956 *
957 * Serializes access to timerqueue via ops_lock mutex
958 */
959void rtc_timer_do_work(struct work_struct *work)
960{
961 struct rtc_timer *timer;
962 struct timerqueue_node *next;
963 ktime_t now;
964 struct rtc_time tm;
965
966 struct rtc_device *rtc =
967 container_of(work, struct rtc_device, irqwork);
968
969 mutex_lock(&rtc->ops_lock);
970again:
971 __rtc_read_time(rtc, &tm);
972 now = rtc_tm_to_ktime(tm);
973 while ((next = timerqueue_getnext(&rtc->timerqueue))) {
974 if (next->expires > now)
975 break;
976
977 /* expire timer */
978 timer = container_of(next, struct rtc_timer, node);
979 timerqueue_del(&rtc->timerqueue, &timer->node);
980 trace_rtc_timer_dequeue(timer);
981 timer->enabled = 0;
982 if (timer->task.func)
983 timer->task.func(timer->task.private_data);
984
985 trace_rtc_timer_fired(timer);
986 /* Re-add/fwd periodic timers */
987 if (ktime_to_ns(timer->period)) {
988 timer->node.expires = ktime_add(timer->node.expires,
989 timer->period);
990 timer->enabled = 1;
991 timerqueue_add(&rtc->timerqueue, &timer->node);
992 trace_rtc_timer_enqueue(timer);
993 }
994 }
995
996 /* Set next alarm */
997 if (next) {
998 struct rtc_wkalrm alarm;
999 int err;
1000 int retry = 3;
1001
1002 alarm.time = rtc_ktime_to_tm(next->expires);
1003 alarm.enabled = 1;
1004reprogram:
1005 err = __rtc_set_alarm(rtc, &alarm);
1006 if (err == -ETIME)
1007 goto again;
1008 else if (err) {
1009 if (retry-- > 0)
1010 goto reprogram;
1011
1012 timer = container_of(next, struct rtc_timer, node);
1013 timerqueue_del(&rtc->timerqueue, &timer->node);
1014 trace_rtc_timer_dequeue(timer);
1015 timer->enabled = 0;
1016 dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err);
1017 goto again;
1018 }
1019 } else
1020 rtc_alarm_disable(rtc);
1021
1022 pm_relax(rtc->dev.parent);
1023 mutex_unlock(&rtc->ops_lock);
1024}
1025
1026
1027/* rtc_timer_init - Initializes an rtc_timer
1028 * @timer: timer to be intiialized
1029 * @f: function pointer to be called when timer fires
1030 * @data: private data passed to function pointer
1031 *
1032 * Kernel interface to initializing an rtc_timer.
1033 */
1034void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data)
1035{
1036 timerqueue_init(&timer->node);
1037 timer->enabled = 0;
1038 timer->task.func = f;
1039 timer->task.private_data = data;
1040}
1041
1042/* rtc_timer_start - Sets an rtc_timer to fire in the future
1043 * @ rtc: rtc device to be used
1044 * @ timer: timer being set
1045 * @ expires: time at which to expire the timer
1046 * @ period: period that the timer will recur
1047 *
1048 * Kernel interface to set an rtc_timer
1049 */
1050int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
1051 ktime_t expires, ktime_t period)
1052{
1053 int ret = 0;
1054 mutex_lock(&rtc->ops_lock);
1055 if (timer->enabled)
1056 rtc_timer_remove(rtc, timer);
1057
1058 timer->node.expires = expires;
1059 timer->period = period;
1060
1061 ret = rtc_timer_enqueue(rtc, timer);
1062
1063 mutex_unlock(&rtc->ops_lock);
1064 return ret;
1065}
1066
1067/* rtc_timer_cancel - Stops an rtc_timer
1068 * @ rtc: rtc device to be used
1069 * @ timer: timer being set
1070 *
1071 * Kernel interface to cancel an rtc_timer
1072 */
1073void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
1074{
1075 mutex_lock(&rtc->ops_lock);
1076 if (timer->enabled)
1077 rtc_timer_remove(rtc, timer);
1078 mutex_unlock(&rtc->ops_lock);
1079}
1080
1081/**
1082 * rtc_read_offset - Read the amount of rtc offset in parts per billion
1083 * @ rtc: rtc device to be used
1084 * @ offset: the offset in parts per billion
1085 *
1086 * see below for details.
1087 *
1088 * Kernel interface to read rtc clock offset
1089 * Returns 0 on success, or a negative number on error.
1090 * If read_offset() is not implemented for the rtc, return -EINVAL
1091 */
1092int rtc_read_offset(struct rtc_device *rtc, long *offset)
1093{
1094 int ret;
1095
1096 if (!rtc->ops)
1097 return -ENODEV;
1098
1099 if (!rtc->ops->read_offset)
1100 return -EINVAL;
1101
1102 mutex_lock(&rtc->ops_lock);
1103 ret = rtc->ops->read_offset(rtc->dev.parent, offset);
1104 mutex_unlock(&rtc->ops_lock);
1105
1106 trace_rtc_read_offset(*offset, ret);
1107 return ret;
1108}
1109
1110/**
1111 * rtc_set_offset - Adjusts the duration of the average second
1112 * @ rtc: rtc device to be used
1113 * @ offset: the offset in parts per billion
1114 *
1115 * Some rtc's allow an adjustment to the average duration of a second
1116 * to compensate for differences in the actual clock rate due to temperature,
1117 * the crystal, capacitor, etc.
1118 *
1119 * The adjustment applied is as follows:
1120 * t = t0 * (1 + offset * 1e-9)
1121 * where t0 is the measured length of 1 RTC second with offset = 0
1122 *
1123 * Kernel interface to adjust an rtc clock offset.
1124 * Return 0 on success, or a negative number on error.
1125 * If the rtc offset is not setable (or not implemented), return -EINVAL
1126 */
1127int rtc_set_offset(struct rtc_device *rtc, long offset)
1128{
1129 int ret;
1130
1131 if (!rtc->ops)
1132 return -ENODEV;
1133
1134 if (!rtc->ops->set_offset)
1135 return -EINVAL;
1136
1137 mutex_lock(&rtc->ops_lock);
1138 ret = rtc->ops->set_offset(rtc->dev.parent, offset);
1139 mutex_unlock(&rtc->ops_lock);
1140
1141 trace_rtc_set_offset(offset, ret);
1142 return ret;
1143}