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1 | /* |
2 | * RTC subsystem, interface functions |
3 | * |
4 | * Copyright (C) 2005 Tower Technologies |
5 | * Author: Alessandro Zummo <a.zummo@towertech.it> |
6 | * |
7 | * based on arch/arm/common/rtctime.c |
8 | * |
9 | * This program is free software; you can redistribute it and/or modify |
10 | * it under the terms of the GNU General Public License version 2 as |
11 | * published by the Free Software Foundation. |
12 | */ |
13 | |
14 | #include <linux/rtc.h> |
15 | #include <linux/sched.h> |
16 | #include <linux/log2.h> |
17 | |
18 | int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm) |
19 | { |
20 | int err; |
21 | |
22 | err = mutex_lock_interruptible(&rtc->ops_lock); |
23 | if (err) |
24 | return err; |
25 | |
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 | |
35 | mutex_unlock(&rtc->ops_lock); |
36 | return err; |
37 | } |
38 | EXPORT_SYMBOL_GPL(rtc_read_time); |
39 | |
40 | int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm) |
41 | { |
42 | int err; |
43 | |
44 | err = rtc_valid_tm(tm); |
45 | if (err != 0) |
46 | return err; |
47 | |
48 | err = mutex_lock_interruptible(&rtc->ops_lock); |
49 | if (err) |
50 | return err; |
51 | |
52 | if (!rtc->ops) |
53 | err = -ENODEV; |
54 | else if (rtc->ops->set_time) |
55 | err = rtc->ops->set_time(rtc->dev.parent, tm); |
56 | else if (rtc->ops->set_mmss) { |
57 | unsigned long secs; |
58 | err = rtc_tm_to_time(tm, &secs); |
59 | if (err == 0) |
60 | err = rtc->ops->set_mmss(rtc->dev.parent, secs); |
61 | } else |
62 | err = -EINVAL; |
63 | |
64 | mutex_unlock(&rtc->ops_lock); |
65 | return err; |
66 | } |
67 | EXPORT_SYMBOL_GPL(rtc_set_time); |
68 | |
69 | int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs) |
70 | { |
71 | int err; |
72 | |
73 | err = mutex_lock_interruptible(&rtc->ops_lock); |
74 | if (err) |
75 | return err; |
76 | |
77 | if (!rtc->ops) |
78 | err = -ENODEV; |
79 | else if (rtc->ops->set_mmss) |
80 | err = rtc->ops->set_mmss(rtc->dev.parent, secs); |
81 | else if (rtc->ops->read_time && rtc->ops->set_time) { |
82 | struct rtc_time new, old; |
83 | |
84 | err = rtc->ops->read_time(rtc->dev.parent, &old); |
85 | if (err == 0) { |
86 | rtc_time_to_tm(secs, &new); |
87 | |
88 | /* |
89 | * avoid writing when we're going to change the day of |
90 | * the month. We will retry in the next minute. This |
91 | * basically means that if the RTC must not drift |
92 | * by more than 1 minute in 11 minutes. |
93 | */ |
94 | if (!((old.tm_hour == 23 && old.tm_min == 59) || |
95 | (new.tm_hour == 23 && new.tm_min == 59))) |
96 | err = rtc->ops->set_time(rtc->dev.parent, |
97 | &new); |
98 | } |
99 | } |
100 | else |
101 | err = -EINVAL; |
102 | |
103 | mutex_unlock(&rtc->ops_lock); |
104 | |
105 | return err; |
106 | } |
107 | EXPORT_SYMBOL_GPL(rtc_set_mmss); |
108 | |
109 | static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
110 | { |
111 | int err; |
112 | |
113 | err = mutex_lock_interruptible(&rtc->ops_lock); |
114 | if (err) |
115 | return err; |
116 | |
117 | if (rtc->ops == NULL) |
118 | err = -ENODEV; |
119 | else if (!rtc->ops->read_alarm) |
120 | err = -EINVAL; |
121 | else { |
122 | memset(alarm, 0, sizeof(struct rtc_wkalrm)); |
123 | err = rtc->ops->read_alarm(rtc->dev.parent, alarm); |
124 | } |
125 | |
126 | mutex_unlock(&rtc->ops_lock); |
127 | return err; |
128 | } |
129 | |
130 | int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
131 | { |
132 | int err; |
133 | struct rtc_time before, now; |
134 | int first_time = 1; |
135 | unsigned long t_now, t_alm; |
136 | enum { none, day, month, year } missing = none; |
137 | unsigned days; |
138 | |
139 | /* The lower level RTC driver may return -1 in some fields, |
140 | * creating invalid alarm->time values, for reasons like: |
141 | * |
142 | * - The hardware may not be capable of filling them in; |
143 | * many alarms match only on time-of-day fields, not |
144 | * day/month/year calendar data. |
145 | * |
146 | * - Some hardware uses illegal values as "wildcard" match |
147 | * values, which non-Linux firmware (like a BIOS) may try |
148 | * to set up as e.g. "alarm 15 minutes after each hour". |
149 | * Linux uses only oneshot alarms. |
150 | * |
151 | * When we see that here, we deal with it by using values from |
152 | * a current RTC timestamp for any missing (-1) values. The |
153 | * RTC driver prevents "periodic alarm" modes. |
154 | * |
155 | * But this can be racey, because some fields of the RTC timestamp |
156 | * may have wrapped in the interval since we read the RTC alarm, |
157 | * which would lead to us inserting inconsistent values in place |
158 | * of the -1 fields. |
159 | * |
160 | * Reading the alarm and timestamp in the reverse sequence |
161 | * would have the same race condition, and not solve the issue. |
162 | * |
163 | * So, we must first read the RTC timestamp, |
164 | * then read the RTC alarm value, |
165 | * and then read a second RTC timestamp. |
166 | * |
167 | * If any fields of the second timestamp have changed |
168 | * when compared with the first timestamp, then we know |
169 | * our timestamp may be inconsistent with that used by |
170 | * the low-level rtc_read_alarm_internal() function. |
171 | * |
172 | * So, when the two timestamps disagree, we just loop and do |
173 | * the process again to get a fully consistent set of values. |
174 | * |
175 | * This could all instead be done in the lower level driver, |
176 | * but since more than one lower level RTC implementation needs it, |
177 | * then it's probably best best to do it here instead of there.. |
178 | */ |
179 | |
180 | /* Get the "before" timestamp */ |
181 | err = rtc_read_time(rtc, &before); |
182 | if (err < 0) |
183 | return err; |
184 | do { |
185 | if (!first_time) |
186 | memcpy(&before, &now, sizeof(struct rtc_time)); |
187 | first_time = 0; |
188 | |
189 | /* get the RTC alarm values, which may be incomplete */ |
190 | err = rtc_read_alarm_internal(rtc, alarm); |
191 | if (err) |
192 | return err; |
193 | if (!alarm->enabled) |
194 | return 0; |
195 | |
196 | /* full-function RTCs won't have such missing fields */ |
197 | if (rtc_valid_tm(&alarm->time) == 0) |
198 | return 0; |
199 | |
200 | /* get the "after" timestamp, to detect wrapped fields */ |
201 | err = rtc_read_time(rtc, &now); |
202 | if (err < 0) |
203 | return err; |
204 | |
205 | /* note that tm_sec is a "don't care" value here: */ |
206 | } while ( before.tm_min != now.tm_min |
207 | || before.tm_hour != now.tm_hour |
208 | || before.tm_mon != now.tm_mon |
209 | || before.tm_year != now.tm_year); |
210 | |
211 | /* Fill in the missing alarm fields using the timestamp; we |
212 | * know there's at least one since alarm->time is invalid. |
213 | */ |
214 | if (alarm->time.tm_sec == -1) |
215 | alarm->time.tm_sec = now.tm_sec; |
216 | if (alarm->time.tm_min == -1) |
217 | alarm->time.tm_min = now.tm_min; |
218 | if (alarm->time.tm_hour == -1) |
219 | alarm->time.tm_hour = now.tm_hour; |
220 | |
221 | /* For simplicity, only support date rollover for now */ |
222 | if (alarm->time.tm_mday == -1) { |
223 | alarm->time.tm_mday = now.tm_mday; |
224 | missing = day; |
225 | } |
226 | if (alarm->time.tm_mon == -1) { |
227 | alarm->time.tm_mon = now.tm_mon; |
228 | if (missing == none) |
229 | missing = month; |
230 | } |
231 | if (alarm->time.tm_year == -1) { |
232 | alarm->time.tm_year = now.tm_year; |
233 | if (missing == none) |
234 | missing = year; |
235 | } |
236 | |
237 | /* with luck, no rollover is needed */ |
238 | rtc_tm_to_time(&now, &t_now); |
239 | rtc_tm_to_time(&alarm->time, &t_alm); |
240 | if (t_now < t_alm) |
241 | goto done; |
242 | |
243 | switch (missing) { |
244 | |
245 | /* 24 hour rollover ... if it's now 10am Monday, an alarm that |
246 | * that will trigger at 5am will do so at 5am Tuesday, which |
247 | * could also be in the next month or year. This is a common |
248 | * case, especially for PCs. |
249 | */ |
250 | case day: |
251 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day"); |
252 | t_alm += 24 * 60 * 60; |
253 | rtc_time_to_tm(t_alm, &alarm->time); |
254 | break; |
255 | |
256 | /* Month rollover ... if it's the 31th, an alarm on the 3rd will |
257 | * be next month. An alarm matching on the 30th, 29th, or 28th |
258 | * may end up in the month after that! Many newer PCs support |
259 | * this type of alarm. |
260 | */ |
261 | case month: |
262 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month"); |
263 | do { |
264 | if (alarm->time.tm_mon < 11) |
265 | alarm->time.tm_mon++; |
266 | else { |
267 | alarm->time.tm_mon = 0; |
268 | alarm->time.tm_year++; |
269 | } |
270 | days = rtc_month_days(alarm->time.tm_mon, |
271 | alarm->time.tm_year); |
272 | } while (days < alarm->time.tm_mday); |
273 | break; |
274 | |
275 | /* Year rollover ... easy except for leap years! */ |
276 | case year: |
277 | dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year"); |
278 | do { |
279 | alarm->time.tm_year++; |
280 | } while (rtc_valid_tm(&alarm->time) != 0); |
281 | break; |
282 | |
283 | default: |
284 | dev_warn(&rtc->dev, "alarm rollover not handled\n"); |
285 | } |
286 | |
287 | done: |
288 | return 0; |
289 | } |
290 | EXPORT_SYMBOL_GPL(rtc_read_alarm); |
291 | |
292 | int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) |
293 | { |
294 | int err; |
295 | |
296 | err = rtc_valid_tm(&alarm->time); |
297 | if (err != 0) |
298 | return err; |
299 | |
300 | err = mutex_lock_interruptible(&rtc->ops_lock); |
301 | if (err) |
302 | return err; |
303 | |
304 | if (!rtc->ops) |
305 | err = -ENODEV; |
306 | else if (!rtc->ops->set_alarm) |
307 | err = -EINVAL; |
308 | else |
309 | err = rtc->ops->set_alarm(rtc->dev.parent, alarm); |
310 | |
311 | mutex_unlock(&rtc->ops_lock); |
312 | return err; |
313 | } |
314 | EXPORT_SYMBOL_GPL(rtc_set_alarm); |
315 | |
316 | int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled) |
317 | { |
318 | int err = mutex_lock_interruptible(&rtc->ops_lock); |
319 | if (err) |
320 | return err; |
321 | |
322 | if (!rtc->ops) |
323 | err = -ENODEV; |
324 | else if (!rtc->ops->alarm_irq_enable) |
325 | err = -EINVAL; |
326 | else |
327 | err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled); |
328 | |
329 | mutex_unlock(&rtc->ops_lock); |
330 | return err; |
331 | } |
332 | EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable); |
333 | |
334 | int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) |
335 | { |
336 | int err = mutex_lock_interruptible(&rtc->ops_lock); |
337 | if (err) |
338 | return err; |
339 | |
340 | #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL |
341 | if (enabled == 0 && rtc->uie_irq_active) { |
342 | mutex_unlock(&rtc->ops_lock); |
343 | return rtc_dev_update_irq_enable_emul(rtc, enabled); |
344 | } |
345 | #endif |
346 | |
347 | if (!rtc->ops) |
348 | err = -ENODEV; |
349 | else if (!rtc->ops->update_irq_enable) |
350 | err = -EINVAL; |
351 | else |
352 | err = rtc->ops->update_irq_enable(rtc->dev.parent, enabled); |
353 | |
354 | mutex_unlock(&rtc->ops_lock); |
355 | |
356 | #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL |
357 | /* |
358 | * Enable emulation if the driver did not provide |
359 | * the update_irq_enable function pointer or if returned |
360 | * -EINVAL to signal that it has been configured without |
361 | * interrupts or that are not available at the moment. |
362 | */ |
363 | if (err == -EINVAL) |
364 | err = rtc_dev_update_irq_enable_emul(rtc, enabled); |
365 | #endif |
366 | return err; |
367 | } |
368 | EXPORT_SYMBOL_GPL(rtc_update_irq_enable); |
369 | |
370 | /** |
371 | * rtc_update_irq - report RTC periodic, alarm, and/or update irqs |
372 | * @rtc: the rtc device |
373 | * @num: how many irqs are being reported (usually one) |
374 | * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF |
375 | * Context: any |
376 | */ |
377 | void rtc_update_irq(struct rtc_device *rtc, |
378 | unsigned long num, unsigned long events) |
379 | { |
380 | unsigned long flags; |
381 | |
382 | spin_lock_irqsave(&rtc->irq_lock, flags); |
383 | rtc->irq_data = (rtc->irq_data + (num << 8)) | events; |
384 | spin_unlock_irqrestore(&rtc->irq_lock, flags); |
385 | |
386 | spin_lock_irqsave(&rtc->irq_task_lock, flags); |
387 | if (rtc->irq_task) |
388 | rtc->irq_task->func(rtc->irq_task->private_data); |
389 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
390 | |
391 | wake_up_interruptible(&rtc->irq_queue); |
392 | kill_fasync(&rtc->async_queue, SIGIO, POLL_IN); |
393 | } |
394 | EXPORT_SYMBOL_GPL(rtc_update_irq); |
395 | |
396 | static int __rtc_match(struct device *dev, void *data) |
397 | { |
398 | char *name = (char *)data; |
399 | |
400 | if (strcmp(dev_name(dev), name) == 0) |
401 | return 1; |
402 | return 0; |
403 | } |
404 | |
405 | struct rtc_device *rtc_class_open(char *name) |
406 | { |
407 | struct device *dev; |
408 | struct rtc_device *rtc = NULL; |
409 | |
410 | dev = class_find_device(rtc_class, NULL, name, __rtc_match); |
411 | if (dev) |
412 | rtc = to_rtc_device(dev); |
413 | |
414 | if (rtc) { |
415 | if (!try_module_get(rtc->owner)) { |
416 | put_device(dev); |
417 | rtc = NULL; |
418 | } |
419 | } |
420 | |
421 | return rtc; |
422 | } |
423 | EXPORT_SYMBOL_GPL(rtc_class_open); |
424 | |
425 | void rtc_class_close(struct rtc_device *rtc) |
426 | { |
427 | module_put(rtc->owner); |
428 | put_device(&rtc->dev); |
429 | } |
430 | EXPORT_SYMBOL_GPL(rtc_class_close); |
431 | |
432 | int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task) |
433 | { |
434 | int retval = -EBUSY; |
435 | |
436 | if (task == NULL || task->func == NULL) |
437 | return -EINVAL; |
438 | |
439 | /* Cannot register while the char dev is in use */ |
440 | if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags)) |
441 | return -EBUSY; |
442 | |
443 | spin_lock_irq(&rtc->irq_task_lock); |
444 | if (rtc->irq_task == NULL) { |
445 | rtc->irq_task = task; |
446 | retval = 0; |
447 | } |
448 | spin_unlock_irq(&rtc->irq_task_lock); |
449 | |
450 | clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags); |
451 | |
452 | return retval; |
453 | } |
454 | EXPORT_SYMBOL_GPL(rtc_irq_register); |
455 | |
456 | void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task) |
457 | { |
458 | spin_lock_irq(&rtc->irq_task_lock); |
459 | if (rtc->irq_task == task) |
460 | rtc->irq_task = NULL; |
461 | spin_unlock_irq(&rtc->irq_task_lock); |
462 | } |
463 | EXPORT_SYMBOL_GPL(rtc_irq_unregister); |
464 | |
465 | /** |
466 | * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs |
467 | * @rtc: the rtc device |
468 | * @task: currently registered with rtc_irq_register() |
469 | * @enabled: true to enable periodic IRQs |
470 | * Context: any |
471 | * |
472 | * Note that rtc_irq_set_freq() should previously have been used to |
473 | * specify the desired frequency of periodic IRQ task->func() callbacks. |
474 | */ |
475 | int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled) |
476 | { |
477 | int err = 0; |
478 | unsigned long flags; |
479 | |
480 | if (rtc->ops->irq_set_state == NULL) |
481 | return -ENXIO; |
482 | |
483 | spin_lock_irqsave(&rtc->irq_task_lock, flags); |
484 | if (rtc->irq_task != NULL && task == NULL) |
485 | err = -EBUSY; |
486 | if (rtc->irq_task != task) |
487 | err = -EACCES; |
488 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
489 | |
490 | if (err == 0) |
491 | err = rtc->ops->irq_set_state(rtc->dev.parent, enabled); |
492 | |
493 | return err; |
494 | } |
495 | EXPORT_SYMBOL_GPL(rtc_irq_set_state); |
496 | |
497 | /** |
498 | * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ |
499 | * @rtc: the rtc device |
500 | * @task: currently registered with rtc_irq_register() |
501 | * @freq: positive frequency with which task->func() will be called |
502 | * Context: any |
503 | * |
504 | * Note that rtc_irq_set_state() is used to enable or disable the |
505 | * periodic IRQs. |
506 | */ |
507 | int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq) |
508 | { |
509 | int err = 0; |
510 | unsigned long flags; |
511 | |
512 | if (rtc->ops->irq_set_freq == NULL) |
513 | return -ENXIO; |
514 | |
515 | spin_lock_irqsave(&rtc->irq_task_lock, flags); |
516 | if (rtc->irq_task != NULL && task == NULL) |
517 | err = -EBUSY; |
518 | if (rtc->irq_task != task) |
519 | err = -EACCES; |
520 | spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
521 | |
522 | if (err == 0) { |
523 | err = rtc->ops->irq_set_freq(rtc->dev.parent, freq); |
524 | if (err == 0) |
525 | rtc->irq_freq = freq; |
526 | } |
527 | return err; |
528 | } |
529 | EXPORT_SYMBOL_GPL(rtc_irq_set_freq); |
530 |
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