1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * RTC subsystem, interface functions |
4 | * |
5 | * Copyright (C) 2005 Tower Technologies |
6 | * Author: Alessandro Zummo <a.zummo@towertech.it> |
7 | * |
8 | * based on arch/arm/common/rtctime.c |
9 | */ |
10 | |
11 | #include <linux/rtc.h> |
12 | #include <linux/sched.h> |
13 | #include <linux/module.h> |
14 | #include <linux/log2.h> |
15 | #include <linux/workqueue.h> |
16 | |
17 | #define CREATE_TRACE_POINTS |
18 | #include <trace/events/rtc.h> |
19 | |
20 | static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer); |
21 | static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer); |
22 | |
23 | static void rtc_add_offset(struct rtc_device *rtc, struct rtc_time *tm) |
24 | { |
25 | time64_t secs; |
26 | |
27 | if (!rtc->offset_secs) |
28 | return; |
29 | |
30 | secs = rtc_tm_to_time64(tm); |
31 | |
32 | /* |
33 | * Since the reading time values from RTC device are always in the RTC |
34 | * original valid range, but we need to skip the overlapped region |
35 | * between expanded range and original range, which is no need to add |
36 | * the offset. |
37 | */ |
38 | if ((rtc->start_secs > rtc->range_min && secs >= rtc->start_secs) || |
39 | (rtc->start_secs < rtc->range_min && |
40 | secs <= (rtc->start_secs + rtc->range_max - rtc->range_min))) |
41 | return; |
42 | |
43 | rtc_time64_to_tm(time: secs + rtc->offset_secs, tm); |
44 | } |
45 | |
46 | static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm) |
47 | { |
48 | time64_t secs; |
49 | |
50 | if (!rtc->offset_secs) |
51 | return; |
52 | |
53 | secs = rtc_tm_to_time64(tm); |
54 | |
55 | /* |
56 | * If the setting time values are in the valid range of RTC hardware |
57 | * device, then no need to subtract the offset when setting time to RTC |
58 | * device. Otherwise we need to subtract the offset to make the time |
59 | * values are valid for RTC hardware device. |
60 | */ |
61 | if (secs >= rtc->range_min && secs <= rtc->range_max) |
62 | return; |
63 | |
64 | rtc_time64_to_tm(time: secs - rtc->offset_secs, tm); |
65 | } |
66 | |
67 | static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm) |
68 | { |
69 | if (rtc->range_min != rtc->range_max) { |
70 | time64_t time = rtc_tm_to_time64(tm); |
71 | time64_t range_min = rtc->set_start_time ? rtc->start_secs : |
72 | rtc->range_min; |
73 | timeu64_t range_max = rtc->set_start_time ? |
74 | (rtc->start_secs + rtc->range_max - rtc->range_min) : |
75 | rtc->range_max; |
76 | |
77 | if (time < range_min || time > range_max) |
78 | return -ERANGE; |
79 | } |
80 | |
81 | return 0; |
82 | } |
83 | |
84 | static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm) |
85 | { |
86 | int err; |
87 | |
88 | if (!rtc->ops) { |
89 | err = -ENODEV; |
90 | } else if (!rtc->ops->read_time) { |
91 | err = -EINVAL; |
92 | } else { |
93 | memset(tm, 0, sizeof(struct rtc_time)); |
94 | err = rtc->ops->read_time(rtc->dev.parent, tm); |
95 | if (err < 0) { |
96 | dev_dbg(&rtc->dev, "read_time: fail to read: %d\n" , |
97 | err); |
98 | return err; |
99 | } |
100 | |
101 | rtc_add_offset(rtc, tm); |
102 | |
103 | err = rtc_valid_tm(tm); |
104 | if (err < 0) |
105 | dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n" ); |
106 | } |
107 | return err; |
108 | } |
109 | |
110 | int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm) |
111 | { |
112 | int err; |
113 | |
114 | err = mutex_lock_interruptible(&rtc->ops_lock); |
115 | if (err) |
116 | return err; |
117 | |
118 | err = __rtc_read_time(rtc, tm); |
119 | mutex_unlock(lock: &rtc->ops_lock); |
120 | |
121 | trace_rtc_read_time(secs: rtc_tm_to_time64(tm), err); |
122 | return err; |
123 | } |
124 | EXPORT_SYMBOL_GPL(rtc_read_time); |
125 | |
126 | int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm) |
127 | { |
128 | int err, uie; |
129 | |
130 | err = rtc_valid_tm(tm); |
131 | if (err != 0) |
132 | return err; |
133 | |
134 | err = rtc_valid_range(rtc, tm); |
135 | if (err) |
136 | return err; |
137 | |
138 | rtc_subtract_offset(rtc, tm); |
139 | |
140 | #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL |
141 | uie = rtc->uie_rtctimer.enabled || rtc->uie_irq_active; |
142 | #else |
143 | uie = rtc->uie_rtctimer.enabled; |
144 | #endif |
145 | if (uie) { |
146 | err = rtc_update_irq_enable(rtc, enabled: 0); |
147 | if (err) |
148 | return err; |
149 | } |
150 | |
151 | err = mutex_lock_interruptible(&rtc->ops_lock); |
152 | if (err) |
153 | return err; |
154 | |
155 | if (!rtc->ops) |
156 | err = -ENODEV; |
157 | else if (rtc->ops->set_time) |
158 | err = rtc->ops->set_time(rtc->dev.parent, tm); |
159 | else |
160 | err = -EINVAL; |
161 | |
162 | pm_stay_awake(dev: rtc->dev.parent); |
163 | mutex_unlock(lock: &rtc->ops_lock); |
164 | /* A timer might have just expired */ |
165 | schedule_work(work: &rtc->irqwork); |
166 | |
167 | if (uie) { |
168 | err = rtc_update_irq_enable(rtc, enabled: 1); |
169 | if (err) |
170 | return err; |
171 | } |
172 | |
173 | trace_rtc_set_time(secs: rtc_tm_to_time64(tm), err); |
174 | return err; |
175 | } |
176 | EXPORT_SYMBOL_GPL(rtc_set_time); |
177 | |
178 | static int rtc_read_alarm_internal(struct rtc_device *rtc, |
179 | struct rtc_wkalrm *alarm) |
180 | { |
181 | int err; |
182 | |
183 | err = mutex_lock_interruptible(&rtc->ops_lock); |
184 | if (err) |
185 | return err; |
186 | |
187 | if (!rtc->ops) { |
188 | err = -ENODEV; |
189 | } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->read_alarm) { |
190 | err = -EINVAL; |
191 | } else { |
192 | alarm->enabled = 0; |
193 | alarm->pending = 0; |
194 | alarm->time.tm_sec = -1; |
195 | alarm->time.tm_min = -1; |
196 | alarm->time.tm_hour = -1; |
197 | alarm->time.tm_mday = -1; |
198 | alarm->time.tm_mon = -1; |
199 | alarm->time.tm_year = -1; |
200 | alarm->time.tm_wday = -1; |
201 | alarm->time.tm_yday = -1; |
202 | alarm->time.tm_isdst = -1; |
203 | err = rtc->ops->read_alarm(rtc->dev.parent, alarm); |
204 | } |
205 | |
206 | mutex_unlock(lock: &rtc->ops_lock); |
207 | |
208 | trace_rtc_read_alarm(secs: rtc_tm_to_time64(tm: &alarm->time), err); |
209 | return err; |
210 | } |
211 | |
212 | int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
213 | { |
214 | int err; |
215 | struct rtc_time before, now; |
216 | int first_time = 1; |
217 | time64_t t_now, t_alm; |
218 | enum { none, day, month, year } missing = none; |
219 | unsigned int days; |
220 | |
221 | /* The lower level RTC driver may return -1 in some fields, |
222 | * creating invalid alarm->time values, for reasons like: |
223 | * |
224 | * - The hardware may not be capable of filling them in; |
225 | * many alarms match only on time-of-day fields, not |
226 | * day/month/year calendar data. |
227 | * |
228 | * - Some hardware uses illegal values as "wildcard" match |
229 | * values, which non-Linux firmware (like a BIOS) may try |
230 | * to set up as e.g. "alarm 15 minutes after each hour". |
231 | * Linux uses only oneshot alarms. |
232 | * |
233 | * When we see that here, we deal with it by using values from |
234 | * a current RTC timestamp for any missing (-1) values. The |
235 | * RTC driver prevents "periodic alarm" modes. |
236 | * |
237 | * But this can be racey, because some fields of the RTC timestamp |
238 | * may have wrapped in the interval since we read the RTC alarm, |
239 | * which would lead to us inserting inconsistent values in place |
240 | * of the -1 fields. |
241 | * |
242 | * Reading the alarm and timestamp in the reverse sequence |
243 | * would have the same race condition, and not solve the issue. |
244 | * |
245 | * So, we must first read the RTC timestamp, |
246 | * then read the RTC alarm value, |
247 | * and then read a second RTC timestamp. |
248 | * |
249 | * If any fields of the second timestamp have changed |
250 | * when compared with the first timestamp, then we know |
251 | * our timestamp may be inconsistent with that used by |
252 | * the low-level rtc_read_alarm_internal() function. |
253 | * |
254 | * So, when the two timestamps disagree, we just loop and do |
255 | * the process again to get a fully consistent set of values. |
256 | * |
257 | * This could all instead be done in the lower level driver, |
258 | * but since more than one lower level RTC implementation needs it, |
259 | * then it's probably best to do it here instead of there.. |
260 | */ |
261 | |
262 | /* Get the "before" timestamp */ |
263 | err = rtc_read_time(rtc, &before); |
264 | if (err < 0) |
265 | return err; |
266 | do { |
267 | if (!first_time) |
268 | memcpy(&before, &now, sizeof(struct rtc_time)); |
269 | first_time = 0; |
270 | |
271 | /* get the RTC alarm values, which may be incomplete */ |
272 | err = rtc_read_alarm_internal(rtc, alarm); |
273 | if (err) |
274 | return err; |
275 | |
276 | /* full-function RTCs won't have such missing fields */ |
277 | if (rtc_valid_tm(tm: &alarm->time) == 0) { |
278 | rtc_add_offset(rtc, tm: &alarm->time); |
279 | return 0; |
280 | } |
281 | |
282 | /* get the "after" timestamp, to detect wrapped fields */ |
283 | err = rtc_read_time(rtc, &now); |
284 | if (err < 0) |
285 | return err; |
286 | |
287 | /* note that tm_sec is a "don't care" value here: */ |
288 | } while (before.tm_min != now.tm_min || |
289 | before.tm_hour != now.tm_hour || |
290 | before.tm_mon != now.tm_mon || |
291 | before.tm_year != now.tm_year); |
292 | |
293 | /* Fill in the missing alarm fields using the timestamp; we |
294 | * know there's at least one since alarm->time is invalid. |
295 | */ |
296 | if (alarm->time.tm_sec == -1) |
297 | alarm->time.tm_sec = now.tm_sec; |
298 | if (alarm->time.tm_min == -1) |
299 | alarm->time.tm_min = now.tm_min; |
300 | if (alarm->time.tm_hour == -1) |
301 | alarm->time.tm_hour = now.tm_hour; |
302 | |
303 | /* For simplicity, only support date rollover for now */ |
304 | if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) { |
305 | alarm->time.tm_mday = now.tm_mday; |
306 | missing = day; |
307 | } |
308 | if ((unsigned int)alarm->time.tm_mon >= 12) { |
309 | alarm->time.tm_mon = now.tm_mon; |
310 | if (missing == none) |
311 | missing = month; |
312 | } |
313 | if (alarm->time.tm_year == -1) { |
314 | alarm->time.tm_year = now.tm_year; |
315 | if (missing == none) |
316 | missing = year; |
317 | } |
318 | |
319 | /* Can't proceed if alarm is still invalid after replacing |
320 | * missing fields. |
321 | */ |
322 | err = rtc_valid_tm(tm: &alarm->time); |
323 | if (err) |
324 | goto done; |
325 | |
326 | /* with luck, no rollover is needed */ |
327 | t_now = rtc_tm_to_time64(tm: &now); |
328 | t_alm = rtc_tm_to_time64(tm: &alarm->time); |
329 | if (t_now < t_alm) |
330 | goto done; |
331 | |
332 | switch (missing) { |
333 | /* 24 hour rollover ... if it's now 10am Monday, an alarm that |
334 | * that will trigger at 5am will do so at 5am Tuesday, which |
335 | * could also be in the next month or year. This is a common |
336 | * case, especially for PCs. |
337 | */ |
338 | case day: |
339 | dev_dbg(&rtc->dev, "alarm rollover: %s\n" , "day" ); |
340 | t_alm += 24 * 60 * 60; |
341 | rtc_time64_to_tm(time: t_alm, tm: &alarm->time); |
342 | break; |
343 | |
344 | /* Month rollover ... if it's the 31th, an alarm on the 3rd will |
345 | * be next month. An alarm matching on the 30th, 29th, or 28th |
346 | * may end up in the month after that! Many newer PCs support |
347 | * this type of alarm. |
348 | */ |
349 | case month: |
350 | dev_dbg(&rtc->dev, "alarm rollover: %s\n" , "month" ); |
351 | do { |
352 | if (alarm->time.tm_mon < 11) { |
353 | alarm->time.tm_mon++; |
354 | } else { |
355 | alarm->time.tm_mon = 0; |
356 | alarm->time.tm_year++; |
357 | } |
358 | days = rtc_month_days(month: alarm->time.tm_mon, |
359 | year: alarm->time.tm_year); |
360 | } while (days < alarm->time.tm_mday); |
361 | break; |
362 | |
363 | /* Year rollover ... easy except for leap years! */ |
364 | case year: |
365 | dev_dbg(&rtc->dev, "alarm rollover: %s\n" , "year" ); |
366 | do { |
367 | alarm->time.tm_year++; |
368 | } while (!is_leap_year(year: alarm->time.tm_year + 1900) && |
369 | rtc_valid_tm(tm: &alarm->time) != 0); |
370 | break; |
371 | |
372 | default: |
373 | dev_warn(&rtc->dev, "alarm rollover not handled\n" ); |
374 | } |
375 | |
376 | err = rtc_valid_tm(tm: &alarm->time); |
377 | |
378 | done: |
379 | if (err && alarm->enabled) |
380 | dev_warn(&rtc->dev, "invalid alarm value: %ptR\n" , |
381 | &alarm->time); |
382 | |
383 | return err; |
384 | } |
385 | |
386 | int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
387 | { |
388 | int err; |
389 | |
390 | err = mutex_lock_interruptible(&rtc->ops_lock); |
391 | if (err) |
392 | return err; |
393 | if (!rtc->ops) { |
394 | err = -ENODEV; |
395 | } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features)) { |
396 | err = -EINVAL; |
397 | } else { |
398 | memset(alarm, 0, sizeof(struct rtc_wkalrm)); |
399 | alarm->enabled = rtc->aie_timer.enabled; |
400 | alarm->time = rtc_ktime_to_tm(kt: rtc->aie_timer.node.expires); |
401 | } |
402 | mutex_unlock(lock: &rtc->ops_lock); |
403 | |
404 | trace_rtc_read_alarm(secs: rtc_tm_to_time64(tm: &alarm->time), err); |
405 | return err; |
406 | } |
407 | EXPORT_SYMBOL_GPL(rtc_read_alarm); |
408 | |
409 | static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
410 | { |
411 | struct rtc_time tm; |
412 | time64_t now, scheduled; |
413 | int err; |
414 | |
415 | err = rtc_valid_tm(tm: &alarm->time); |
416 | if (err) |
417 | return err; |
418 | |
419 | scheduled = rtc_tm_to_time64(tm: &alarm->time); |
420 | |
421 | /* Make sure we're not setting alarms in the past */ |
422 | err = __rtc_read_time(rtc, tm: &tm); |
423 | if (err) |
424 | return err; |
425 | now = rtc_tm_to_time64(tm: &tm); |
426 | |
427 | if (scheduled <= now) |
428 | return -ETIME; |
429 | /* |
430 | * XXX - We just checked to make sure the alarm time is not |
431 | * in the past, but there is still a race window where if |
432 | * the is alarm set for the next second and the second ticks |
433 | * over right here, before we set the alarm. |
434 | */ |
435 | |
436 | rtc_subtract_offset(rtc, tm: &alarm->time); |
437 | |
438 | if (!rtc->ops) |
439 | err = -ENODEV; |
440 | else if (!test_bit(RTC_FEATURE_ALARM, rtc->features)) |
441 | err = -EINVAL; |
442 | else |
443 | err = rtc->ops->set_alarm(rtc->dev.parent, alarm); |
444 | |
445 | trace_rtc_set_alarm(secs: rtc_tm_to_time64(tm: &alarm->time), err); |
446 | return err; |
447 | } |
448 | |
449 | int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
450 | { |
451 | ktime_t alarm_time; |
452 | int err; |
453 | |
454 | if (!rtc->ops) |
455 | return -ENODEV; |
456 | else if (!test_bit(RTC_FEATURE_ALARM, rtc->features)) |
457 | return -EINVAL; |
458 | |
459 | err = rtc_valid_tm(tm: &alarm->time); |
460 | if (err != 0) |
461 | return err; |
462 | |
463 | err = rtc_valid_range(rtc, tm: &alarm->time); |
464 | if (err) |
465 | return err; |
466 | |
467 | err = mutex_lock_interruptible(&rtc->ops_lock); |
468 | if (err) |
469 | return err; |
470 | if (rtc->aie_timer.enabled) |
471 | rtc_timer_remove(rtc, timer: &rtc->aie_timer); |
472 | |
473 | alarm_time = rtc_tm_to_ktime(tm: alarm->time); |
474 | /* |
475 | * Round down so we never miss a deadline, checking for past deadline is |
476 | * done in __rtc_set_alarm |
477 | */ |
478 | if (test_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features)) |
479 | alarm_time = ktime_sub_ns(alarm_time, (u64)alarm->time.tm_sec * NSEC_PER_SEC); |
480 | |
481 | rtc->aie_timer.node.expires = alarm_time; |
482 | rtc->aie_timer.period = 0; |
483 | if (alarm->enabled) |
484 | err = rtc_timer_enqueue(rtc, timer: &rtc->aie_timer); |
485 | |
486 | mutex_unlock(lock: &rtc->ops_lock); |
487 | |
488 | return err; |
489 | } |
490 | EXPORT_SYMBOL_GPL(rtc_set_alarm); |
491 | |
492 | /* Called once per device from rtc_device_register */ |
493 | int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
494 | { |
495 | int err; |
496 | struct rtc_time now; |
497 | |
498 | err = rtc_valid_tm(tm: &alarm->time); |
499 | if (err != 0) |
500 | return err; |
501 | |
502 | err = rtc_read_time(rtc, &now); |
503 | if (err) |
504 | return err; |
505 | |
506 | err = mutex_lock_interruptible(&rtc->ops_lock); |
507 | if (err) |
508 | return err; |
509 | |
510 | rtc->aie_timer.node.expires = rtc_tm_to_ktime(tm: alarm->time); |
511 | rtc->aie_timer.period = 0; |
512 | |
513 | /* Alarm has to be enabled & in the future for us to enqueue it */ |
514 | if (alarm->enabled && (rtc_tm_to_ktime(tm: now) < |
515 | rtc->aie_timer.node.expires)) { |
516 | rtc->aie_timer.enabled = 1; |
517 | timerqueue_add(head: &rtc->timerqueue, node: &rtc->aie_timer.node); |
518 | trace_rtc_timer_enqueue(timer: &rtc->aie_timer); |
519 | } |
520 | mutex_unlock(lock: &rtc->ops_lock); |
521 | return err; |
522 | } |
523 | EXPORT_SYMBOL_GPL(rtc_initialize_alarm); |
524 | |
525 | int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled) |
526 | { |
527 | int err; |
528 | |
529 | err = mutex_lock_interruptible(&rtc->ops_lock); |
530 | if (err) |
531 | return err; |
532 | |
533 | if (rtc->aie_timer.enabled != enabled) { |
534 | if (enabled) |
535 | err = rtc_timer_enqueue(rtc, timer: &rtc->aie_timer); |
536 | else |
537 | rtc_timer_remove(rtc, timer: &rtc->aie_timer); |
538 | } |
539 | |
540 | if (err) |
541 | /* nothing */; |
542 | else if (!rtc->ops) |
543 | err = -ENODEV; |
544 | else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable) |
545 | err = -EINVAL; |
546 | else |
547 | err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled); |
548 | |
549 | mutex_unlock(lock: &rtc->ops_lock); |
550 | |
551 | trace_rtc_alarm_irq_enable(enabled, err); |
552 | return err; |
553 | } |
554 | EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable); |
555 | |
556 | int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) |
557 | { |
558 | int err; |
559 | |
560 | err = mutex_lock_interruptible(&rtc->ops_lock); |
561 | if (err) |
562 | return err; |
563 | |
564 | #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL |
565 | if (enabled == 0 && rtc->uie_irq_active) { |
566 | mutex_unlock(lock: &rtc->ops_lock); |
567 | return rtc_dev_update_irq_enable_emul(rtc, enabled: 0); |
568 | } |
569 | #endif |
570 | /* make sure we're changing state */ |
571 | if (rtc->uie_rtctimer.enabled == enabled) |
572 | goto out; |
573 | |
574 | if (!test_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features) || |
575 | !test_bit(RTC_FEATURE_ALARM, rtc->features)) { |
576 | mutex_unlock(lock: &rtc->ops_lock); |
577 | #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL |
578 | return rtc_dev_update_irq_enable_emul(rtc, enabled); |
579 | #else |
580 | return -EINVAL; |
581 | #endif |
582 | } |
583 | |
584 | if (enabled) { |
585 | struct rtc_time tm; |
586 | ktime_t now, onesec; |
587 | |
588 | err = __rtc_read_time(rtc, tm: &tm); |
589 | if (err) |
590 | goto out; |
591 | onesec = ktime_set(secs: 1, nsecs: 0); |
592 | now = rtc_tm_to_ktime(tm); |
593 | rtc->uie_rtctimer.node.expires = ktime_add(now, onesec); |
594 | rtc->uie_rtctimer.period = ktime_set(secs: 1, nsecs: 0); |
595 | err = rtc_timer_enqueue(rtc, timer: &rtc->uie_rtctimer); |
596 | } else { |
597 | rtc_timer_remove(rtc, timer: &rtc->uie_rtctimer); |
598 | } |
599 | |
600 | out: |
601 | mutex_unlock(lock: &rtc->ops_lock); |
602 | |
603 | return err; |
604 | } |
605 | EXPORT_SYMBOL_GPL(rtc_update_irq_enable); |
606 | |
607 | /** |
608 | * rtc_handle_legacy_irq - AIE, UIE and PIE event hook |
609 | * @rtc: pointer to the rtc device |
610 | * @num: number of occurence of the event |
611 | * @mode: type of the event, RTC_AF, RTC_UF of RTC_PF |
612 | * |
613 | * This function is called when an AIE, UIE or PIE mode interrupt |
614 | * has occurred (or been emulated). |
615 | * |
616 | */ |
617 | void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode) |
618 | { |
619 | unsigned long flags; |
620 | |
621 | /* mark one irq of the appropriate mode */ |
622 | spin_lock_irqsave(&rtc->irq_lock, flags); |
623 | rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF | mode); |
624 | spin_unlock_irqrestore(lock: &rtc->irq_lock, flags); |
625 | |
626 | wake_up_interruptible(&rtc->irq_queue); |
627 | kill_fasync(&rtc->async_queue, SIGIO, POLL_IN); |
628 | } |
629 | |
630 | /** |
631 | * rtc_aie_update_irq - AIE mode rtctimer hook |
632 | * @rtc: pointer to the rtc_device |
633 | * |
634 | * This functions is called when the aie_timer expires. |
635 | */ |
636 | void rtc_aie_update_irq(struct rtc_device *rtc) |
637 | { |
638 | rtc_handle_legacy_irq(rtc, num: 1, RTC_AF); |
639 | } |
640 | |
641 | /** |
642 | * rtc_uie_update_irq - UIE mode rtctimer hook |
643 | * @rtc: pointer to the rtc_device |
644 | * |
645 | * This functions is called when the uie_timer expires. |
646 | */ |
647 | void rtc_uie_update_irq(struct rtc_device *rtc) |
648 | { |
649 | rtc_handle_legacy_irq(rtc, num: 1, RTC_UF); |
650 | } |
651 | |
652 | /** |
653 | * rtc_pie_update_irq - PIE mode hrtimer hook |
654 | * @timer: pointer to the pie mode hrtimer |
655 | * |
656 | * This function is used to emulate PIE mode interrupts |
657 | * using an hrtimer. This function is called when the periodic |
658 | * hrtimer expires. |
659 | */ |
660 | enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer) |
661 | { |
662 | struct rtc_device *rtc; |
663 | ktime_t period; |
664 | u64 count; |
665 | |
666 | rtc = container_of(timer, struct rtc_device, pie_timer); |
667 | |
668 | period = NSEC_PER_SEC / rtc->irq_freq; |
669 | count = hrtimer_forward_now(timer, interval: period); |
670 | |
671 | rtc_handle_legacy_irq(rtc, num: count, RTC_PF); |
672 | |
673 | return HRTIMER_RESTART; |
674 | } |
675 | |
676 | /** |
677 | * rtc_update_irq - Triggered when a RTC interrupt occurs. |
678 | * @rtc: the rtc device |
679 | * @num: how many irqs are being reported (usually one) |
680 | * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF |
681 | * Context: any |
682 | */ |
683 | void rtc_update_irq(struct rtc_device *rtc, |
684 | unsigned long num, unsigned long events) |
685 | { |
686 | if (IS_ERR_OR_NULL(ptr: rtc)) |
687 | return; |
688 | |
689 | pm_stay_awake(dev: rtc->dev.parent); |
690 | schedule_work(work: &rtc->irqwork); |
691 | } |
692 | EXPORT_SYMBOL_GPL(rtc_update_irq); |
693 | |
694 | struct rtc_device *rtc_class_open(const char *name) |
695 | { |
696 | struct device *dev; |
697 | struct rtc_device *rtc = NULL; |
698 | |
699 | dev = class_find_device_by_name(class: rtc_class, name); |
700 | if (dev) |
701 | rtc = to_rtc_device(dev); |
702 | |
703 | if (rtc) { |
704 | if (!try_module_get(module: rtc->owner)) { |
705 | put_device(dev); |
706 | rtc = NULL; |
707 | } |
708 | } |
709 | |
710 | return rtc; |
711 | } |
712 | EXPORT_SYMBOL_GPL(rtc_class_open); |
713 | |
714 | void rtc_class_close(struct rtc_device *rtc) |
715 | { |
716 | module_put(module: rtc->owner); |
717 | put_device(dev: &rtc->dev); |
718 | } |
719 | EXPORT_SYMBOL_GPL(rtc_class_close); |
720 | |
721 | static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled) |
722 | { |
723 | /* |
724 | * We always cancel the timer here first, because otherwise |
725 | * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK); |
726 | * when we manage to start the timer before the callback |
727 | * returns HRTIMER_RESTART. |
728 | * |
729 | * We cannot use hrtimer_cancel() here as a running callback |
730 | * could be blocked on rtc->irq_task_lock and hrtimer_cancel() |
731 | * would spin forever. |
732 | */ |
733 | if (hrtimer_try_to_cancel(timer: &rtc->pie_timer) < 0) |
734 | return -1; |
735 | |
736 | if (enabled) { |
737 | ktime_t period = NSEC_PER_SEC / rtc->irq_freq; |
738 | |
739 | hrtimer_start(timer: &rtc->pie_timer, tim: period, mode: HRTIMER_MODE_REL); |
740 | } |
741 | return 0; |
742 | } |
743 | |
744 | /** |
745 | * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs |
746 | * @rtc: the rtc device |
747 | * @enabled: true to enable periodic IRQs |
748 | * Context: any |
749 | * |
750 | * Note that rtc_irq_set_freq() should previously have been used to |
751 | * specify the desired frequency of periodic IRQ. |
752 | */ |
753 | int rtc_irq_set_state(struct rtc_device *rtc, int enabled) |
754 | { |
755 | int err = 0; |
756 | |
757 | while (rtc_update_hrtimer(rtc, enabled) < 0) |
758 | cpu_relax(); |
759 | |
760 | rtc->pie_enabled = enabled; |
761 | |
762 | trace_rtc_irq_set_state(enabled, err); |
763 | return err; |
764 | } |
765 | |
766 | /** |
767 | * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ |
768 | * @rtc: the rtc device |
769 | * @freq: positive frequency |
770 | * Context: any |
771 | * |
772 | * Note that rtc_irq_set_state() is used to enable or disable the |
773 | * periodic IRQs. |
774 | */ |
775 | int rtc_irq_set_freq(struct rtc_device *rtc, int freq) |
776 | { |
777 | int err = 0; |
778 | |
779 | if (freq <= 0 || freq > RTC_MAX_FREQ) |
780 | return -EINVAL; |
781 | |
782 | rtc->irq_freq = freq; |
783 | while (rtc->pie_enabled && rtc_update_hrtimer(rtc, enabled: 1) < 0) |
784 | cpu_relax(); |
785 | |
786 | trace_rtc_irq_set_freq(freq, err); |
787 | return err; |
788 | } |
789 | |
790 | /** |
791 | * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue |
792 | * @rtc: rtc device |
793 | * @timer: timer being added. |
794 | * |
795 | * Enqueues a timer onto the rtc devices timerqueue and sets |
796 | * the next alarm event appropriately. |
797 | * |
798 | * Sets the enabled bit on the added timer. |
799 | * |
800 | * Must hold ops_lock for proper serialization of timerqueue |
801 | */ |
802 | static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer) |
803 | { |
804 | struct timerqueue_node *next = timerqueue_getnext(head: &rtc->timerqueue); |
805 | struct rtc_time tm; |
806 | ktime_t now; |
807 | int err; |
808 | |
809 | err = __rtc_read_time(rtc, tm: &tm); |
810 | if (err) |
811 | return err; |
812 | |
813 | timer->enabled = 1; |
814 | now = rtc_tm_to_ktime(tm); |
815 | |
816 | /* Skip over expired timers */ |
817 | while (next) { |
818 | if (next->expires >= now) |
819 | break; |
820 | next = timerqueue_iterate_next(node: next); |
821 | } |
822 | |
823 | timerqueue_add(head: &rtc->timerqueue, node: &timer->node); |
824 | trace_rtc_timer_enqueue(timer); |
825 | if (!next || ktime_before(cmp1: timer->node.expires, cmp2: next->expires)) { |
826 | struct rtc_wkalrm alarm; |
827 | |
828 | alarm.time = rtc_ktime_to_tm(kt: timer->node.expires); |
829 | alarm.enabled = 1; |
830 | err = __rtc_set_alarm(rtc, alarm: &alarm); |
831 | if (err == -ETIME) { |
832 | pm_stay_awake(dev: rtc->dev.parent); |
833 | schedule_work(work: &rtc->irqwork); |
834 | } else if (err) { |
835 | timerqueue_del(head: &rtc->timerqueue, node: &timer->node); |
836 | trace_rtc_timer_dequeue(timer); |
837 | timer->enabled = 0; |
838 | return err; |
839 | } |
840 | } |
841 | return 0; |
842 | } |
843 | |
844 | static void rtc_alarm_disable(struct rtc_device *rtc) |
845 | { |
846 | if (!rtc->ops || !test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable) |
847 | return; |
848 | |
849 | rtc->ops->alarm_irq_enable(rtc->dev.parent, false); |
850 | trace_rtc_alarm_irq_enable(enabled: 0, err: 0); |
851 | } |
852 | |
853 | /** |
854 | * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue |
855 | * @rtc: rtc device |
856 | * @timer: timer being removed. |
857 | * |
858 | * Removes a timer onto the rtc devices timerqueue and sets |
859 | * the next alarm event appropriately. |
860 | * |
861 | * Clears the enabled bit on the removed timer. |
862 | * |
863 | * Must hold ops_lock for proper serialization of timerqueue |
864 | */ |
865 | static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer) |
866 | { |
867 | struct timerqueue_node *next = timerqueue_getnext(head: &rtc->timerqueue); |
868 | |
869 | timerqueue_del(head: &rtc->timerqueue, node: &timer->node); |
870 | trace_rtc_timer_dequeue(timer); |
871 | timer->enabled = 0; |
872 | if (next == &timer->node) { |
873 | struct rtc_wkalrm alarm; |
874 | int err; |
875 | |
876 | next = timerqueue_getnext(head: &rtc->timerqueue); |
877 | if (!next) { |
878 | rtc_alarm_disable(rtc); |
879 | return; |
880 | } |
881 | alarm.time = rtc_ktime_to_tm(kt: next->expires); |
882 | alarm.enabled = 1; |
883 | err = __rtc_set_alarm(rtc, alarm: &alarm); |
884 | if (err == -ETIME) { |
885 | pm_stay_awake(dev: rtc->dev.parent); |
886 | schedule_work(work: &rtc->irqwork); |
887 | } |
888 | } |
889 | } |
890 | |
891 | /** |
892 | * rtc_timer_do_work - Expires rtc timers |
893 | * @work: work item |
894 | * |
895 | * Expires rtc timers. Reprograms next alarm event if needed. |
896 | * Called via worktask. |
897 | * |
898 | * Serializes access to timerqueue via ops_lock mutex |
899 | */ |
900 | void rtc_timer_do_work(struct work_struct *work) |
901 | { |
902 | struct rtc_timer *timer; |
903 | struct timerqueue_node *next; |
904 | ktime_t now; |
905 | struct rtc_time tm; |
906 | |
907 | struct rtc_device *rtc = |
908 | container_of(work, struct rtc_device, irqwork); |
909 | |
910 | mutex_lock(&rtc->ops_lock); |
911 | again: |
912 | __rtc_read_time(rtc, tm: &tm); |
913 | now = rtc_tm_to_ktime(tm); |
914 | while ((next = timerqueue_getnext(head: &rtc->timerqueue))) { |
915 | if (next->expires > now) |
916 | break; |
917 | |
918 | /* expire timer */ |
919 | timer = container_of(next, struct rtc_timer, node); |
920 | timerqueue_del(head: &rtc->timerqueue, node: &timer->node); |
921 | trace_rtc_timer_dequeue(timer); |
922 | timer->enabled = 0; |
923 | if (timer->func) |
924 | timer->func(timer->rtc); |
925 | |
926 | trace_rtc_timer_fired(timer); |
927 | /* Re-add/fwd periodic timers */ |
928 | if (ktime_to_ns(kt: timer->period)) { |
929 | timer->node.expires = ktime_add(timer->node.expires, |
930 | timer->period); |
931 | timer->enabled = 1; |
932 | timerqueue_add(head: &rtc->timerqueue, node: &timer->node); |
933 | trace_rtc_timer_enqueue(timer); |
934 | } |
935 | } |
936 | |
937 | /* Set next alarm */ |
938 | if (next) { |
939 | struct rtc_wkalrm alarm; |
940 | int err; |
941 | int retry = 3; |
942 | |
943 | alarm.time = rtc_ktime_to_tm(kt: next->expires); |
944 | alarm.enabled = 1; |
945 | reprogram: |
946 | err = __rtc_set_alarm(rtc, alarm: &alarm); |
947 | if (err == -ETIME) { |
948 | goto again; |
949 | } else if (err) { |
950 | if (retry-- > 0) |
951 | goto reprogram; |
952 | |
953 | timer = container_of(next, struct rtc_timer, node); |
954 | timerqueue_del(head: &rtc->timerqueue, node: &timer->node); |
955 | trace_rtc_timer_dequeue(timer); |
956 | timer->enabled = 0; |
957 | dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n" , err); |
958 | goto again; |
959 | } |
960 | } else { |
961 | rtc_alarm_disable(rtc); |
962 | } |
963 | |
964 | pm_relax(dev: rtc->dev.parent); |
965 | mutex_unlock(lock: &rtc->ops_lock); |
966 | } |
967 | |
968 | /* rtc_timer_init - Initializes an rtc_timer |
969 | * @timer: timer to be intiialized |
970 | * @f: function pointer to be called when timer fires |
971 | * @rtc: pointer to the rtc_device |
972 | * |
973 | * Kernel interface to initializing an rtc_timer. |
974 | */ |
975 | void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r), |
976 | struct rtc_device *rtc) |
977 | { |
978 | timerqueue_init(node: &timer->node); |
979 | timer->enabled = 0; |
980 | timer->func = f; |
981 | timer->rtc = rtc; |
982 | } |
983 | |
984 | /* rtc_timer_start - Sets an rtc_timer to fire in the future |
985 | * @ rtc: rtc device to be used |
986 | * @ timer: timer being set |
987 | * @ expires: time at which to expire the timer |
988 | * @ period: period that the timer will recur |
989 | * |
990 | * Kernel interface to set an rtc_timer |
991 | */ |
992 | int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer, |
993 | ktime_t expires, ktime_t period) |
994 | { |
995 | int ret = 0; |
996 | |
997 | mutex_lock(&rtc->ops_lock); |
998 | if (timer->enabled) |
999 | rtc_timer_remove(rtc, timer); |
1000 | |
1001 | timer->node.expires = expires; |
1002 | timer->period = period; |
1003 | |
1004 | ret = rtc_timer_enqueue(rtc, timer); |
1005 | |
1006 | mutex_unlock(lock: &rtc->ops_lock); |
1007 | return ret; |
1008 | } |
1009 | |
1010 | /* rtc_timer_cancel - Stops an rtc_timer |
1011 | * @ rtc: rtc device to be used |
1012 | * @ timer: timer being set |
1013 | * |
1014 | * Kernel interface to cancel an rtc_timer |
1015 | */ |
1016 | void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer) |
1017 | { |
1018 | mutex_lock(&rtc->ops_lock); |
1019 | if (timer->enabled) |
1020 | rtc_timer_remove(rtc, timer); |
1021 | mutex_unlock(lock: &rtc->ops_lock); |
1022 | } |
1023 | |
1024 | /** |
1025 | * rtc_read_offset - Read the amount of rtc offset in parts per billion |
1026 | * @rtc: rtc device to be used |
1027 | * @offset: the offset in parts per billion |
1028 | * |
1029 | * see below for details. |
1030 | * |
1031 | * Kernel interface to read rtc clock offset |
1032 | * Returns 0 on success, or a negative number on error. |
1033 | * If read_offset() is not implemented for the rtc, return -EINVAL |
1034 | */ |
1035 | int rtc_read_offset(struct rtc_device *rtc, long *offset) |
1036 | { |
1037 | int ret; |
1038 | |
1039 | if (!rtc->ops) |
1040 | return -ENODEV; |
1041 | |
1042 | if (!rtc->ops->read_offset) |
1043 | return -EINVAL; |
1044 | |
1045 | mutex_lock(&rtc->ops_lock); |
1046 | ret = rtc->ops->read_offset(rtc->dev.parent, offset); |
1047 | mutex_unlock(lock: &rtc->ops_lock); |
1048 | |
1049 | trace_rtc_read_offset(offset: *offset, err: ret); |
1050 | return ret; |
1051 | } |
1052 | |
1053 | /** |
1054 | * rtc_set_offset - Adjusts the duration of the average second |
1055 | * @rtc: rtc device to be used |
1056 | * @offset: the offset in parts per billion |
1057 | * |
1058 | * Some rtc's allow an adjustment to the average duration of a second |
1059 | * to compensate for differences in the actual clock rate due to temperature, |
1060 | * the crystal, capacitor, etc. |
1061 | * |
1062 | * The adjustment applied is as follows: |
1063 | * t = t0 * (1 + offset * 1e-9) |
1064 | * where t0 is the measured length of 1 RTC second with offset = 0 |
1065 | * |
1066 | * Kernel interface to adjust an rtc clock offset. |
1067 | * Return 0 on success, or a negative number on error. |
1068 | * If the rtc offset is not setable (or not implemented), return -EINVAL |
1069 | */ |
1070 | int rtc_set_offset(struct rtc_device *rtc, long offset) |
1071 | { |
1072 | int ret; |
1073 | |
1074 | if (!rtc->ops) |
1075 | return -ENODEV; |
1076 | |
1077 | if (!rtc->ops->set_offset) |
1078 | return -EINVAL; |
1079 | |
1080 | mutex_lock(&rtc->ops_lock); |
1081 | ret = rtc->ops->set_offset(rtc->dev.parent, offset); |
1082 | mutex_unlock(lock: &rtc->ops_lock); |
1083 | |
1084 | trace_rtc_set_offset(offset, err: ret); |
1085 | return ret; |
1086 | } |
1087 | |