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 pm_stay_awake(rtc->dev.parent); 76 mutex_unlock(&rtc->ops_lock); 77 /* A timer might have just expired */ 78 schedule_work(&rtc->irqwork); 79 return err; 80} 81EXPORT_SYMBOL_GPL(rtc_set_time); 82 83int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs) 84{ 85 int err; 86 87 err = mutex_lock_interruptible(&rtc->ops_lock); 88 if (err) 89 return err; 90 91 if (!rtc->ops) 92 err = -ENODEV; 93 else if (rtc->ops->set_mmss) 94 err = rtc->ops->set_mmss(rtc->dev.parent, secs); 95 else if (rtc->ops->read_time && rtc->ops->set_time) { 96 struct rtc_time new, old; 97 98 err = rtc->ops->read_time(rtc->dev.parent, &old); 99 if (err == 0) { 100 rtc_time_to_tm(secs, &new); 101 102 /* 103 * avoid writing when we're going to change the day of 104 * the month. We will retry in the next minute. This 105 * basically means that if the RTC must not drift 106 * by more than 1 minute in 11 minutes. 107 */ 108 if (!((old.tm_hour == 23 && old.tm_min == 59) || 109 (new.tm_hour == 23 && new.tm_min == 59))) 110 err = rtc->ops->set_time(rtc->dev.parent, 111 &new); 112 } 113 } else { 114 err = -EINVAL; 115 } 116 117 pm_stay_awake(rtc->dev.parent); 118 mutex_unlock(&rtc->ops_lock); 119 /* A timer might have just expired */ 120 schedule_work(&rtc->irqwork); 121 122 return err; 123} 124EXPORT_SYMBOL_GPL(rtc_set_mmss); 125 126static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 127{ 128 int err; 129 130 err = mutex_lock_interruptible(&rtc->ops_lock); 131 if (err) 132 return err; 133 134 if (rtc->ops == NULL) 135 err = -ENODEV; 136 else if (!rtc->ops->read_alarm) 137 err = -EINVAL; 138 else { 139 memset(alarm, 0, sizeof(struct rtc_wkalrm)); 140 err = rtc->ops->read_alarm(rtc->dev.parent, alarm); 141 } 142 143 mutex_unlock(&rtc->ops_lock); 144 return err; 145} 146 147int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 148{ 149 int err; 150 struct rtc_time before, now; 151 int first_time = 1; 152 unsigned long t_now, t_alm; 153 enum { none, day, month, year } missing = none; 154 unsigned days; 155 156 /* The lower level RTC driver may return -1 in some fields, 157 * creating invalid alarm->time values, for reasons like: 158 * 159 * - The hardware may not be capable of filling them in; 160 * many alarms match only on time-of-day fields, not 161 * day/month/year calendar data. 162 * 163 * - Some hardware uses illegal values as "wildcard" match 164 * values, which non-Linux firmware (like a BIOS) may try 165 * to set up as e.g. "alarm 15 minutes after each hour". 166 * Linux uses only oneshot alarms. 167 * 168 * When we see that here, we deal with it by using values from 169 * a current RTC timestamp for any missing (-1) values. The 170 * RTC driver prevents "periodic alarm" modes. 171 * 172 * But this can be racey, because some fields of the RTC timestamp 173 * may have wrapped in the interval since we read the RTC alarm, 174 * which would lead to us inserting inconsistent values in place 175 * of the -1 fields. 176 * 177 * Reading the alarm and timestamp in the reverse sequence 178 * would have the same race condition, and not solve the issue. 179 * 180 * So, we must first read the RTC timestamp, 181 * then read the RTC alarm value, 182 * and then read a second RTC timestamp. 183 * 184 * If any fields of the second timestamp have changed 185 * when compared with the first timestamp, then we know 186 * our timestamp may be inconsistent with that used by 187 * the low-level rtc_read_alarm_internal() function. 188 * 189 * So, when the two timestamps disagree, we just loop and do 190 * the process again to get a fully consistent set of values. 191 * 192 * This could all instead be done in the lower level driver, 193 * but since more than one lower level RTC implementation needs it, 194 * then it's probably best best to do it here instead of there.. 195 */ 196 197 /* Get the "before" timestamp */ 198 err = rtc_read_time(rtc, &before); 199 if (err < 0) 200 return err; 201 do { 202 if (!first_time) 203 memcpy(&before, &now, sizeof(struct rtc_time)); 204 first_time = 0; 205 206 /* get the RTC alarm values, which may be incomplete */ 207 err = rtc_read_alarm_internal(rtc, alarm); 208 if (err) 209 return err; 210 211 /* full-function RTCs won't have such missing fields */ 212 if (rtc_valid_tm(&alarm->time) == 0) 213 return 0; 214 215 /* get the "after" timestamp, to detect wrapped fields */ 216 err = rtc_read_time(rtc, &now); 217 if (err < 0) 218 return err; 219 220 /* note that tm_sec is a "don't care" value here: */ 221 } while ( before.tm_min != now.tm_min 222 || before.tm_hour != now.tm_hour 223 || before.tm_mon != now.tm_mon 224 || before.tm_year != now.tm_year); 225 226 /* Fill in the missing alarm fields using the timestamp; we 227 * know there's at least one since alarm->time is invalid. 228 */ 229 if (alarm->time.tm_sec == -1) 230 alarm->time.tm_sec = now.tm_sec; 231 if (alarm->time.tm_min == -1) 232 alarm->time.tm_min = now.tm_min; 233 if (alarm->time.tm_hour == -1) 234 alarm->time.tm_hour = now.tm_hour; 235 236 /* For simplicity, only support date rollover for now */ 237 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) { 238 alarm->time.tm_mday = now.tm_mday; 239 missing = day; 240 } 241 if ((unsigned)alarm->time.tm_mon >= 12) { 242 alarm->time.tm_mon = now.tm_mon; 243 if (missing == none) 244 missing = month; 245 } 246 if (alarm->time.tm_year == -1) { 247 alarm->time.tm_year = now.tm_year; 248 if (missing == none) 249 missing = year; 250 } 251 252 /* with luck, no rollover is needed */ 253 rtc_tm_to_time(&now, &t_now); 254 rtc_tm_to_time(&alarm->time, &t_alm); 255 if (t_now < t_alm) 256 goto done; 257 258 switch (missing) { 259 260 /* 24 hour rollover ... if it's now 10am Monday, an alarm that 261 * that will trigger at 5am will do so at 5am Tuesday, which 262 * could also be in the next month or year. This is a common 263 * case, especially for PCs. 264 */ 265 case day: 266 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day"); 267 t_alm += 24 * 60 * 60; 268 rtc_time_to_tm(t_alm, &alarm->time); 269 break; 270 271 /* Month rollover ... if it's the 31th, an alarm on the 3rd will 272 * be next month. An alarm matching on the 30th, 29th, or 28th 273 * may end up in the month after that! Many newer PCs support 274 * this type of alarm. 275 */ 276 case month: 277 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month"); 278 do { 279 if (alarm->time.tm_mon < 11) 280 alarm->time.tm_mon++; 281 else { 282 alarm->time.tm_mon = 0; 283 alarm->time.tm_year++; 284 } 285 days = rtc_month_days(alarm->time.tm_mon, 286 alarm->time.tm_year); 287 } while (days < alarm->time.tm_mday); 288 break; 289 290 /* Year rollover ... easy except for leap years! */ 291 case year: 292 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year"); 293 do { 294 alarm->time.tm_year++; 295 } while (!is_leap_year(alarm->time.tm_year + 1900) 296 && rtc_valid_tm(&alarm->time) != 0); 297 break; 298 299 default: 300 dev_warn(&rtc->dev, "alarm rollover not handled\n"); 301 } 302 303done: 304 err = rtc_valid_tm(&alarm->time); 305 306 if (err) { 307 dev_warn(&rtc->dev, "invalid alarm value: %d-%d-%d %d:%d:%d\n", 308 alarm->time.tm_year + 1900, alarm->time.tm_mon + 1, 309 alarm->time.tm_mday, alarm->time.tm_hour, alarm->time.tm_min, 310 alarm->time.tm_sec); 311 } 312 313 return err; 314} 315 316int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 317{ 318 int err; 319 320 err = mutex_lock_interruptible(&rtc->ops_lock); 321 if (err) 322 return err; 323 if (rtc->ops == NULL) 324 err = -ENODEV; 325 else if (!rtc->ops->read_alarm) 326 err = -EINVAL; 327 else { 328 memset(alarm, 0, sizeof(struct rtc_wkalrm)); 329 alarm->enabled = rtc->aie_timer.enabled; 330 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires); 331 } 332 mutex_unlock(&rtc->ops_lock); 333 334 return err; 335} 336EXPORT_SYMBOL_GPL(rtc_read_alarm); 337 338static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 339{ 340 struct rtc_time tm; 341 long now, scheduled; 342 int err; 343 344 err = rtc_valid_tm(&alarm->time); 345 if (err) 346 return err; 347 rtc_tm_to_time(&alarm->time, &scheduled); 348 349 /* Make sure we're not setting alarms in the past */ 350 err = __rtc_read_time(rtc, &tm); 351 if (err) 352 return err; 353 rtc_tm_to_time(&tm, &now); 354 if (scheduled <= now) 355 return -ETIME; 356 /* 357 * XXX - We just checked to make sure the alarm time is not 358 * in the past, but there is still a race window where if 359 * the is alarm set for the next second and the second ticks 360 * over right here, before we set the alarm. 361 */ 362 363 if (!rtc->ops) 364 err = -ENODEV; 365 else if (!rtc->ops->set_alarm) 366 err = -EINVAL; 367 else 368 err = rtc->ops->set_alarm(rtc->dev.parent, alarm); 369 370 return err; 371} 372 373int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 374{ 375 int err; 376 377 err = rtc_valid_tm(&alarm->time); 378 if (err != 0) 379 return err; 380 381 err = mutex_lock_interruptible(&rtc->ops_lock); 382 if (err) 383 return err; 384 if (rtc->aie_timer.enabled) 385 rtc_timer_remove(rtc, &rtc->aie_timer); 386 387 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time); 388 rtc->aie_timer.period = ktime_set(0, 0); 389 if (alarm->enabled) 390 err = rtc_timer_enqueue(rtc, &rtc->aie_timer); 391 392 mutex_unlock(&rtc->ops_lock); 393 return err; 394} 395EXPORT_SYMBOL_GPL(rtc_set_alarm); 396 397/* Called once per device from rtc_device_register */ 398int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 399{ 400 int err; 401 struct rtc_time now; 402 403 err = rtc_valid_tm(&alarm->time); 404 if (err != 0) 405 return err; 406 407 err = rtc_read_time(rtc, &now); 408 if (err) 409 return err; 410 411 err = mutex_lock_interruptible(&rtc->ops_lock); 412 if (err) 413 return err; 414 415 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time); 416 rtc->aie_timer.period = ktime_set(0, 0); 417 418 /* Alarm has to be enabled & in the futrure for us to enqueue it */ 419 if (alarm->enabled && (rtc_tm_to_ktime(now).tv64 < 420 rtc->aie_timer.node.expires.tv64)) { 421 422 rtc->aie_timer.enabled = 1; 423 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node); 424 } 425 mutex_unlock(&rtc->ops_lock); 426 return err; 427} 428EXPORT_SYMBOL_GPL(rtc_initialize_alarm); 429 430 431 432int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled) 433{ 434 int err = mutex_lock_interruptible(&rtc->ops_lock); 435 if (err) 436 return err; 437 438 if (rtc->aie_timer.enabled != enabled) { 439 if (enabled) 440 err = rtc_timer_enqueue(rtc, &rtc->aie_timer); 441 else 442 rtc_timer_remove(rtc, &rtc->aie_timer); 443 } 444 445 if (err) 446 /* nothing */; 447 else if (!rtc->ops) 448 err = -ENODEV; 449 else if (!rtc->ops->alarm_irq_enable) 450 err = -EINVAL; 451 else 452 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled); 453 454 mutex_unlock(&rtc->ops_lock); 455 return err; 456} 457EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable); 458 459int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) 460{ 461 int err = mutex_lock_interruptible(&rtc->ops_lock); 462 if (err) 463 return err; 464 465#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL 466 if (enabled == 0 && rtc->uie_irq_active) { 467 mutex_unlock(&rtc->ops_lock); 468 return rtc_dev_update_irq_enable_emul(rtc, 0); 469 } 470#endif 471 /* make sure we're changing state */ 472 if (rtc->uie_rtctimer.enabled == enabled) 473 goto out; 474 475 if (rtc->uie_unsupported) { 476 err = -EINVAL; 477 goto out; 478 } 479 480 if (enabled) { 481 struct rtc_time tm; 482 ktime_t now, onesec; 483 484 __rtc_read_time(rtc, &tm); 485 onesec = ktime_set(1, 0); 486 now = rtc_tm_to_ktime(tm); 487 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec); 488 rtc->uie_rtctimer.period = ktime_set(1, 0); 489 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer); 490 } else 491 rtc_timer_remove(rtc, &rtc->uie_rtctimer); 492 493out: 494 mutex_unlock(&rtc->ops_lock); 495#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL 496 /* 497 * Enable emulation if the driver did not provide 498 * the update_irq_enable function pointer or if returned 499 * -EINVAL to signal that it has been configured without 500 * interrupts or that are not available at the moment. 501 */ 502 if (err == -EINVAL) 503 err = rtc_dev_update_irq_enable_emul(rtc, enabled); 504#endif 505 return err; 506 507} 508EXPORT_SYMBOL_GPL(rtc_update_irq_enable); 509 510 511/** 512 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook 513 * @rtc: pointer to the rtc device 514 * 515 * This function is called when an AIE, UIE or PIE mode interrupt 516 * has occurred (or been emulated). 517 * 518 * Triggers the registered irq_task function callback. 519 */ 520void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode) 521{ 522 unsigned long flags; 523 524 /* mark one irq of the appropriate mode */ 525 spin_lock_irqsave(&rtc->irq_lock, flags); 526 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode); 527 spin_unlock_irqrestore(&rtc->irq_lock, flags); 528 529 /* call the task func */ 530 spin_lock_irqsave(&rtc->irq_task_lock, flags); 531 if (rtc->irq_task) 532 rtc->irq_task->func(rtc->irq_task->private_data); 533 spin_unlock_irqrestore(&rtc->irq_task_lock, flags); 534 535 wake_up_interruptible(&rtc->irq_queue); 536 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN); 537} 538 539 540/** 541 * rtc_aie_update_irq - AIE mode rtctimer hook 542 * @private: pointer to the rtc_device 543 * 544 * This functions is called when the aie_timer expires. 545 */ 546void rtc_aie_update_irq(void *private) 547{ 548 struct rtc_device *rtc = (struct rtc_device *)private; 549 rtc_handle_legacy_irq(rtc, 1, RTC_AF); 550} 551 552 553/** 554 * rtc_uie_update_irq - UIE mode rtctimer hook 555 * @private: pointer to the rtc_device 556 * 557 * This functions is called when the uie_timer expires. 558 */ 559void rtc_uie_update_irq(void *private) 560{ 561 struct rtc_device *rtc = (struct rtc_device *)private; 562 rtc_handle_legacy_irq(rtc, 1, RTC_UF); 563} 564 565 566/** 567 * rtc_pie_update_irq - PIE mode hrtimer hook 568 * @timer: pointer to the pie mode hrtimer 569 * 570 * This function is used to emulate PIE mode interrupts 571 * using an hrtimer. This function is called when the periodic 572 * hrtimer expires. 573 */ 574enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer) 575{ 576 struct rtc_device *rtc; 577 ktime_t period; 578 int count; 579 rtc = container_of(timer, struct rtc_device, pie_timer); 580 581 period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq); 582 count = hrtimer_forward_now(timer, period); 583 584 rtc_handle_legacy_irq(rtc, count, RTC_PF); 585 586 return HRTIMER_RESTART; 587} 588 589/** 590 * rtc_update_irq - Triggered when a RTC interrupt occurs. 591 * @rtc: the rtc device 592 * @num: how many irqs are being reported (usually one) 593 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF 594 * Context: any 595 */ 596void rtc_update_irq(struct rtc_device *rtc, 597 unsigned long num, unsigned long events) 598{ 599 if (unlikely(IS_ERR_OR_NULL(rtc))) 600 return; 601 602 pm_stay_awake(rtc->dev.parent); 603 schedule_work(&rtc->irqwork); 604} 605EXPORT_SYMBOL_GPL(rtc_update_irq); 606 607static int __rtc_match(struct device *dev, const void *data) 608{ 609 const char *name = data; 610 611 if (strcmp(dev_name(dev), name) == 0) 612 return 1; 613 return 0; 614} 615 616struct rtc_device *rtc_class_open(const char *name) 617{ 618 struct device *dev; 619 struct rtc_device *rtc = NULL; 620 621 dev = class_find_device(rtc_class, NULL, name, __rtc_match); 622 if (dev) 623 rtc = to_rtc_device(dev); 624 625 if (rtc) { 626 if (!try_module_get(rtc->owner)) { 627 put_device(dev); 628 rtc = NULL; 629 } 630 } 631 632 return rtc; 633} 634EXPORT_SYMBOL_GPL(rtc_class_open); 635 636void rtc_class_close(struct rtc_device *rtc) 637{ 638 module_put(rtc->owner); 639 put_device(&rtc->dev); 640} 641EXPORT_SYMBOL_GPL(rtc_class_close); 642 643int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task) 644{ 645 int retval = -EBUSY; 646 647 if (task == NULL || task->func == NULL) 648 return -EINVAL; 649 650 /* Cannot register while the char dev is in use */ 651 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags)) 652 return -EBUSY; 653 654 spin_lock_irq(&rtc->irq_task_lock); 655 if (rtc->irq_task == NULL) { 656 rtc->irq_task = task; 657 retval = 0; 658 } 659 spin_unlock_irq(&rtc->irq_task_lock); 660 661 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags); 662 663 return retval; 664} 665EXPORT_SYMBOL_GPL(rtc_irq_register); 666 667void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task) 668{ 669 spin_lock_irq(&rtc->irq_task_lock); 670 if (rtc->irq_task == task) 671 rtc->irq_task = NULL; 672 spin_unlock_irq(&rtc->irq_task_lock); 673} 674EXPORT_SYMBOL_GPL(rtc_irq_unregister); 675 676static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled) 677{ 678 /* 679 * We always cancel the timer here first, because otherwise 680 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK); 681 * when we manage to start the timer before the callback 682 * returns HRTIMER_RESTART. 683 * 684 * We cannot use hrtimer_cancel() here as a running callback 685 * could be blocked on rtc->irq_task_lock and hrtimer_cancel() 686 * would spin forever. 687 */ 688 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0) 689 return -1; 690 691 if (enabled) { 692 ktime_t period = ktime_set(0, NSEC_PER_SEC / rtc->irq_freq); 693 694 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL); 695 } 696 return 0; 697} 698 699/** 700 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs 701 * @rtc: the rtc device 702 * @task: currently registered with rtc_irq_register() 703 * @enabled: true to enable periodic IRQs 704 * Context: any 705 * 706 * Note that rtc_irq_set_freq() should previously have been used to 707 * specify the desired frequency of periodic IRQ task->func() callbacks. 708 */ 709int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled) 710{ 711 int err = 0; 712 unsigned long flags; 713 714retry: 715 spin_lock_irqsave(&rtc->irq_task_lock, flags); 716 if (rtc->irq_task != NULL && task == NULL) 717 err = -EBUSY; 718 else if (rtc->irq_task != task) 719 err = -EACCES; 720 else { 721 if (rtc_update_hrtimer(rtc, enabled) < 0) { 722 spin_unlock_irqrestore(&rtc->irq_task_lock, flags); 723 cpu_relax(); 724 goto retry; 725 } 726 rtc->pie_enabled = enabled; 727 } 728 spin_unlock_irqrestore(&rtc->irq_task_lock, flags); 729 return err; 730} 731EXPORT_SYMBOL_GPL(rtc_irq_set_state); 732 733/** 734 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ 735 * @rtc: the rtc device 736 * @task: currently registered with rtc_irq_register() 737 * @freq: positive frequency with which task->func() will be called 738 * Context: any 739 * 740 * Note that rtc_irq_set_state() is used to enable or disable the 741 * periodic IRQs. 742 */ 743int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq) 744{ 745 int err = 0; 746 unsigned long flags; 747 748 if (freq <= 0 || freq > RTC_MAX_FREQ) 749 return -EINVAL; 750retry: 751 spin_lock_irqsave(&rtc->irq_task_lock, flags); 752 if (rtc->irq_task != NULL && task == NULL) 753 err = -EBUSY; 754 else if (rtc->irq_task != task) 755 err = -EACCES; 756 else { 757 rtc->irq_freq = freq; 758 if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) { 759 spin_unlock_irqrestore(&rtc->irq_task_lock, flags); 760 cpu_relax(); 761 goto retry; 762 } 763 } 764 spin_unlock_irqrestore(&rtc->irq_task_lock, flags); 765 return err; 766} 767EXPORT_SYMBOL_GPL(rtc_irq_set_freq); 768 769/** 770 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue 771 * @rtc rtc device 772 * @timer timer being added. 773 * 774 * Enqueues a timer onto the rtc devices timerqueue and sets 775 * the next alarm event appropriately. 776 * 777 * Sets the enabled bit on the added timer. 778 * 779 * Must hold ops_lock for proper serialization of timerqueue 780 */ 781static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer) 782{ 783 timer->enabled = 1; 784 timerqueue_add(&rtc->timerqueue, &timer->node); 785 if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) { 786 struct rtc_wkalrm alarm; 787 int err; 788 alarm.time = rtc_ktime_to_tm(timer->node.expires); 789 alarm.enabled = 1; 790 err = __rtc_set_alarm(rtc, &alarm); 791 if (err == -ETIME) { 792 pm_stay_awake(rtc->dev.parent); 793 schedule_work(&rtc->irqwork); 794 } else if (err) { 795 timerqueue_del(&rtc->timerqueue, &timer->node); 796 timer->enabled = 0; 797 return err; 798 } 799 } 800 return 0; 801} 802 803static void rtc_alarm_disable(struct rtc_device *rtc) 804{ 805 if (!rtc->ops || !rtc->ops->alarm_irq_enable) 806 return; 807 808 rtc->ops->alarm_irq_enable(rtc->dev.parent, false); 809} 810 811/** 812 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue 813 * @rtc rtc device 814 * @timer timer being removed. 815 * 816 * Removes a timer onto the rtc devices timerqueue and sets 817 * the next alarm event appropriately. 818 * 819 * Clears the enabled bit on the removed timer. 820 * 821 * Must hold ops_lock for proper serialization of timerqueue 822 */ 823static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer) 824{ 825 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue); 826 timerqueue_del(&rtc->timerqueue, &timer->node); 827 timer->enabled = 0; 828 if (next == &timer->node) { 829 struct rtc_wkalrm alarm; 830 int err; 831 next = timerqueue_getnext(&rtc->timerqueue); 832 if (!next) { 833 rtc_alarm_disable(rtc); 834 return; 835 } 836 alarm.time = rtc_ktime_to_tm(next->expires); 837 alarm.enabled = 1; 838 err = __rtc_set_alarm(rtc, &alarm); 839 if (err == -ETIME) { 840 pm_stay_awake(rtc->dev.parent); 841 schedule_work(&rtc->irqwork); 842 } 843 } 844} 845 846/** 847 * rtc_timer_do_work - Expires rtc timers 848 * @rtc rtc device 849 * @timer timer being removed. 850 * 851 * Expires rtc timers. Reprograms next alarm event if needed. 852 * Called via worktask. 853 * 854 * Serializes access to timerqueue via ops_lock mutex 855 */ 856void rtc_timer_do_work(struct work_struct *work) 857{ 858 struct rtc_timer *timer; 859 struct timerqueue_node *next; 860 ktime_t now; 861 struct rtc_time tm; 862 863 struct rtc_device *rtc = 864 container_of(work, struct rtc_device, irqwork); 865 866 mutex_lock(&rtc->ops_lock); 867again: 868 __rtc_read_time(rtc, &tm); 869 now = rtc_tm_to_ktime(tm); 870 while ((next = timerqueue_getnext(&rtc->timerqueue))) { 871 if (next->expires.tv64 > now.tv64) 872 break; 873 874 /* expire timer */ 875 timer = container_of(next, struct rtc_timer, node); 876 timerqueue_del(&rtc->timerqueue, &timer->node); 877 timer->enabled = 0; 878 if (timer->task.func) 879 timer->task.func(timer->task.private_data); 880 881 /* Re-add/fwd periodic timers */ 882 if (ktime_to_ns(timer->period)) { 883 timer->node.expires = ktime_add(timer->node.expires, 884 timer->period); 885 timer->enabled = 1; 886 timerqueue_add(&rtc->timerqueue, &timer->node); 887 } 888 } 889 890 /* Set next alarm */ 891 if (next) { 892 struct rtc_wkalrm alarm; 893 int err; 894 alarm.time = rtc_ktime_to_tm(next->expires); 895 alarm.enabled = 1; 896 err = __rtc_set_alarm(rtc, &alarm); 897 if (err == -ETIME) 898 goto again; 899 } else 900 rtc_alarm_disable(rtc); 901 902 pm_relax(rtc->dev.parent); 903 mutex_unlock(&rtc->ops_lock); 904} 905 906 907/* rtc_timer_init - Initializes an rtc_timer 908 * @timer: timer to be intiialized 909 * @f: function pointer to be called when timer fires 910 * @data: private data passed to function pointer 911 * 912 * Kernel interface to initializing an rtc_timer. 913 */ 914void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data) 915{ 916 timerqueue_init(&timer->node); 917 timer->enabled = 0; 918 timer->task.func = f; 919 timer->task.private_data = data; 920} 921 922/* rtc_timer_start - Sets an rtc_timer to fire in the future 923 * @ rtc: rtc device to be used 924 * @ timer: timer being set 925 * @ expires: time at which to expire the timer 926 * @ period: period that the timer will recur 927 * 928 * Kernel interface to set an rtc_timer 929 */ 930int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer, 931 ktime_t expires, ktime_t period) 932{ 933 int ret = 0; 934 mutex_lock(&rtc->ops_lock); 935 if (timer->enabled) 936 rtc_timer_remove(rtc, timer); 937 938 timer->node.expires = expires; 939 timer->period = period; 940 941 ret = rtc_timer_enqueue(rtc, timer); 942 943 mutex_unlock(&rtc->ops_lock); 944 return ret; 945} 946 947/* rtc_timer_cancel - Stops an rtc_timer 948 * @ rtc: rtc device to be used 949 * @ timer: timer being set 950 * 951 * Kernel interface to cancel an rtc_timer 952 */ 953int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer) 954{ 955 int ret = 0; 956 mutex_lock(&rtc->ops_lock); 957 if (timer->enabled) 958 rtc_timer_remove(rtc, timer); 959 mutex_unlock(&rtc->ops_lock); 960 return ret; 961} 962 963 964