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 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 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 37 int 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 } 49 EXPORT_SYMBOL_GPL(rtc_read_time); 50 51 int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm) 52 { 53 int err; 54 55 err = rtc_valid_tm(tm); 56 if (err != 0) 57 return err; 58 59 err = mutex_lock_interruptible(&rtc->ops_lock); 60 if (err) 61 return err; 62 63 if (!rtc->ops) 64 err = -ENODEV; 65 else if (rtc->ops->set_time) 66 err = rtc->ops->set_time(rtc->dev.parent, tm); 67 else if (rtc->ops->set_mmss) { 68 unsigned long secs; 69 err = rtc_tm_to_time(tm, &secs); 70 if (err == 0) 71 err = rtc->ops->set_mmss(rtc->dev.parent, secs); 72 } else 73 err = -EINVAL; 74 75 mutex_unlock(&rtc->ops_lock); 76 return err; 77 } 78 EXPORT_SYMBOL_GPL(rtc_set_time); 79 80 int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs) 81 { 82 int err; 83 84 err = mutex_lock_interruptible(&rtc->ops_lock); 85 if (err) 86 return err; 87 88 if (!rtc->ops) 89 err = -ENODEV; 90 else if (rtc->ops->set_mmss) 91 err = rtc->ops->set_mmss(rtc->dev.parent, secs); 92 else if (rtc->ops->read_time && rtc->ops->set_time) { 93 struct rtc_time new, old; 94 95 err = rtc->ops->read_time(rtc->dev.parent, &old); 96 if (err == 0) { 97 rtc_time_to_tm(secs, &new); 98 99 /* 100 * avoid writing when we're going to change the day of 101 * the month. We will retry in the next minute. This 102 * basically means that if the RTC must not drift 103 * by more than 1 minute in 11 minutes. 104 */ 105 if (!((old.tm_hour == 23 && old.tm_min == 59) || 106 (new.tm_hour == 23 && new.tm_min == 59))) 107 err = rtc->ops->set_time(rtc->dev.parent, 108 &new); 109 } 110 } 111 else 112 err = -EINVAL; 113 114 mutex_unlock(&rtc->ops_lock); 115 116 return err; 117 } 118 EXPORT_SYMBOL_GPL(rtc_set_mmss); 119 120 static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 121 { 122 int err; 123 124 err = mutex_lock_interruptible(&rtc->ops_lock); 125 if (err) 126 return err; 127 128 if (rtc->ops == NULL) 129 err = -ENODEV; 130 else if (!rtc->ops->read_alarm) 131 err = -EINVAL; 132 else { 133 memset(alarm, 0, sizeof(struct rtc_wkalrm)); 134 err = rtc->ops->read_alarm(rtc->dev.parent, alarm); 135 } 136 137 mutex_unlock(&rtc->ops_lock); 138 return err; 139 } 140 141 int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 142 { 143 int err; 144 struct rtc_time before, now; 145 int first_time = 1; 146 unsigned long t_now, t_alm; 147 enum { none, day, month, year } missing = none; 148 unsigned days; 149 150 /* The lower level RTC driver may return -1 in some fields, 151 * creating invalid alarm->time values, for reasons like: 152 * 153 * - The hardware may not be capable of filling them in; 154 * many alarms match only on time-of-day fields, not 155 * day/month/year calendar data. 156 * 157 * - Some hardware uses illegal values as "wildcard" match 158 * values, which non-Linux firmware (like a BIOS) may try 159 * to set up as e.g. "alarm 15 minutes after each hour". 160 * Linux uses only oneshot alarms. 161 * 162 * When we see that here, we deal with it by using values from 163 * a current RTC timestamp for any missing (-1) values. The 164 * RTC driver prevents "periodic alarm" modes. 165 * 166 * But this can be racey, because some fields of the RTC timestamp 167 * may have wrapped in the interval since we read the RTC alarm, 168 * which would lead to us inserting inconsistent values in place 169 * of the -1 fields. 170 * 171 * Reading the alarm and timestamp in the reverse sequence 172 * would have the same race condition, and not solve the issue. 173 * 174 * So, we must first read the RTC timestamp, 175 * then read the RTC alarm value, 176 * and then read a second RTC timestamp. 177 * 178 * If any fields of the second timestamp have changed 179 * when compared with the first timestamp, then we know 180 * our timestamp may be inconsistent with that used by 181 * the low-level rtc_read_alarm_internal() function. 182 * 183 * So, when the two timestamps disagree, we just loop and do 184 * the process again to get a fully consistent set of values. 185 * 186 * This could all instead be done in the lower level driver, 187 * but since more than one lower level RTC implementation needs it, 188 * then it's probably best best to do it here instead of there.. 189 */ 190 191 /* Get the "before" timestamp */ 192 err = rtc_read_time(rtc, &before); 193 if (err < 0) 194 return err; 195 do { 196 if (!first_time) 197 memcpy(&before, &now, sizeof(struct rtc_time)); 198 first_time = 0; 199 200 /* get the RTC alarm values, which may be incomplete */ 201 err = rtc_read_alarm_internal(rtc, alarm); 202 if (err) 203 return err; 204 205 /* full-function RTCs won't have such missing fields */ 206 if (rtc_valid_tm(&alarm->time) == 0) 207 return 0; 208 209 /* get the "after" timestamp, to detect wrapped fields */ 210 err = rtc_read_time(rtc, &now); 211 if (err < 0) 212 return err; 213 214 /* note that tm_sec is a "don't care" value here: */ 215 } while ( before.tm_min != now.tm_min 216 || before.tm_hour != now.tm_hour 217 || before.tm_mon != now.tm_mon 218 || before.tm_year != now.tm_year); 219 220 /* Fill in the missing alarm fields using the timestamp; we 221 * know there's at least one since alarm->time is invalid. 222 */ 223 if (alarm->time.tm_sec == -1) 224 alarm->time.tm_sec = now.tm_sec; 225 if (alarm->time.tm_min == -1) 226 alarm->time.tm_min = now.tm_min; 227 if (alarm->time.tm_hour == -1) 228 alarm->time.tm_hour = now.tm_hour; 229 230 /* For simplicity, only support date rollover for now */ 231 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) { 232 alarm->time.tm_mday = now.tm_mday; 233 missing = day; 234 } 235 if ((unsigned)alarm->time.tm_mon >= 12) { 236 alarm->time.tm_mon = now.tm_mon; 237 if (missing == none) 238 missing = month; 239 } 240 if (alarm->time.tm_year == -1) { 241 alarm->time.tm_year = now.tm_year; 242 if (missing == none) 243 missing = year; 244 } 245 246 /* with luck, no rollover is needed */ 247 rtc_tm_to_time(&now, &t_now); 248 rtc_tm_to_time(&alarm->time, &t_alm); 249 if (t_now < t_alm) 250 goto done; 251 252 switch (missing) { 253 254 /* 24 hour rollover ... if it's now 10am Monday, an alarm that 255 * that will trigger at 5am will do so at 5am Tuesday, which 256 * could also be in the next month or year. This is a common 257 * case, especially for PCs. 258 */ 259 case day: 260 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day"); 261 t_alm += 24 * 60 * 60; 262 rtc_time_to_tm(t_alm, &alarm->time); 263 break; 264 265 /* Month rollover ... if it's the 31th, an alarm on the 3rd will 266 * be next month. An alarm matching on the 30th, 29th, or 28th 267 * may end up in the month after that! Many newer PCs support 268 * this type of alarm. 269 */ 270 case month: 271 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month"); 272 do { 273 if (alarm->time.tm_mon < 11) 274 alarm->time.tm_mon++; 275 else { 276 alarm->time.tm_mon = 0; 277 alarm->time.tm_year++; 278 } 279 days = rtc_month_days(alarm->time.tm_mon, 280 alarm->time.tm_year); 281 } while (days < alarm->time.tm_mday); 282 break; 283 284 /* Year rollover ... easy except for leap years! */ 285 case year: 286 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year"); 287 do { 288 alarm->time.tm_year++; 289 } while (rtc_valid_tm(&alarm->time) != 0); 290 break; 291 292 default: 293 dev_warn(&rtc->dev, "alarm rollover not handled\n"); 294 } 295 296 done: 297 return 0; 298 } 299 300 int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 301 { 302 int err; 303 304 err = mutex_lock_interruptible(&rtc->ops_lock); 305 if (err) 306 return err; 307 if (rtc->ops == NULL) 308 err = -ENODEV; 309 else if (!rtc->ops->read_alarm) 310 err = -EINVAL; 311 else { 312 memset(alarm, 0, sizeof(struct rtc_wkalrm)); 313 alarm->enabled = rtc->aie_timer.enabled; 314 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires); 315 } 316 mutex_unlock(&rtc->ops_lock); 317 318 return err; 319 } 320 EXPORT_SYMBOL_GPL(rtc_read_alarm); 321 322 static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 323 { 324 struct rtc_time tm; 325 long now, scheduled; 326 int err; 327 328 err = rtc_valid_tm(&alarm->time); 329 if (err) 330 return err; 331 rtc_tm_to_time(&alarm->time, &scheduled); 332 333 /* Make sure we're not setting alarms in the past */ 334 err = __rtc_read_time(rtc, &tm); 335 rtc_tm_to_time(&tm, &now); 336 if (scheduled <= now) 337 return -ETIME; 338 /* 339 * XXX - We just checked to make sure the alarm time is not 340 * in the past, but there is still a race window where if 341 * the is alarm set for the next second and the second ticks 342 * over right here, before we set the alarm. 343 */ 344 345 if (!rtc->ops) 346 err = -ENODEV; 347 else if (!rtc->ops->set_alarm) 348 err = -EINVAL; 349 else 350 err = rtc->ops->set_alarm(rtc->dev.parent, alarm); 351 352 return err; 353 } 354 355 int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 356 { 357 int err; 358 359 err = rtc_valid_tm(&alarm->time); 360 if (err != 0) 361 return err; 362 363 err = mutex_lock_interruptible(&rtc->ops_lock); 364 if (err) 365 return err; 366 if (rtc->aie_timer.enabled) { 367 rtc_timer_remove(rtc, &rtc->aie_timer); 368 } 369 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time); 370 rtc->aie_timer.period = ktime_set(0, 0); 371 if (alarm->enabled) { 372 err = rtc_timer_enqueue(rtc, &rtc->aie_timer); 373 } 374 mutex_unlock(&rtc->ops_lock); 375 return err; 376 } 377 EXPORT_SYMBOL_GPL(rtc_set_alarm); 378 379 /* Called once per device from rtc_device_register */ 380 int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 381 { 382 int err; 383 384 err = rtc_valid_tm(&alarm->time); 385 if (err != 0) 386 return err; 387 388 err = mutex_lock_interruptible(&rtc->ops_lock); 389 if (err) 390 return err; 391 392 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time); 393 rtc->aie_timer.period = ktime_set(0, 0); 394 if (alarm->enabled) { 395 rtc->aie_timer.enabled = 1; 396 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node); 397 } 398 mutex_unlock(&rtc->ops_lock); 399 return err; 400 } 401 EXPORT_SYMBOL_GPL(rtc_initialize_alarm); 402 403 404 405 int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled) 406 { 407 int err = mutex_lock_interruptible(&rtc->ops_lock); 408 if (err) 409 return err; 410 411 if (rtc->aie_timer.enabled != enabled) { 412 if (enabled) 413 err = rtc_timer_enqueue(rtc, &rtc->aie_timer); 414 else 415 rtc_timer_remove(rtc, &rtc->aie_timer); 416 } 417 418 if (err) 419 /* nothing */; 420 else if (!rtc->ops) 421 err = -ENODEV; 422 else if (!rtc->ops->alarm_irq_enable) 423 err = -EINVAL; 424 else 425 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled); 426 427 mutex_unlock(&rtc->ops_lock); 428 return err; 429 } 430 EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable); 431 432 int rtc_update_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 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL 439 if (enabled == 0 && rtc->uie_irq_active) { 440 mutex_unlock(&rtc->ops_lock); 441 return rtc_dev_update_irq_enable_emul(rtc, 0); 442 } 443 #endif 444 /* make sure we're changing state */ 445 if (rtc->uie_rtctimer.enabled == enabled) 446 goto out; 447 448 if (enabled) { 449 struct rtc_time tm; 450 ktime_t now, onesec; 451 452 __rtc_read_time(rtc, &tm); 453 onesec = ktime_set(1, 0); 454 now = rtc_tm_to_ktime(tm); 455 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec); 456 rtc->uie_rtctimer.period = ktime_set(1, 0); 457 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer); 458 } else 459 rtc_timer_remove(rtc, &rtc->uie_rtctimer); 460 461 out: 462 mutex_unlock(&rtc->ops_lock); 463 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL 464 /* 465 * Enable emulation if the driver did not provide 466 * the update_irq_enable function pointer or if returned 467 * -EINVAL to signal that it has been configured without 468 * interrupts or that are not available at the moment. 469 */ 470 if (err == -EINVAL) 471 err = rtc_dev_update_irq_enable_emul(rtc, enabled); 472 #endif 473 return err; 474 475 } 476 EXPORT_SYMBOL_GPL(rtc_update_irq_enable); 477 478 479 /** 480 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook 481 * @rtc: pointer to the rtc device 482 * 483 * This function is called when an AIE, UIE or PIE mode interrupt 484 * has occurred (or been emulated). 485 * 486 * Triggers the registered irq_task function callback. 487 */ 488 void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode) 489 { 490 unsigned long flags; 491 492 /* mark one irq of the appropriate mode */ 493 spin_lock_irqsave(&rtc->irq_lock, flags); 494 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF|mode); 495 spin_unlock_irqrestore(&rtc->irq_lock, flags); 496 497 /* call the task func */ 498 spin_lock_irqsave(&rtc->irq_task_lock, flags); 499 if (rtc->irq_task) 500 rtc->irq_task->func(rtc->irq_task->private_data); 501 spin_unlock_irqrestore(&rtc->irq_task_lock, flags); 502 503 wake_up_interruptible(&rtc->irq_queue); 504 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN); 505 } 506 507 508 /** 509 * rtc_aie_update_irq - AIE mode rtctimer hook 510 * @private: pointer to the rtc_device 511 * 512 * This functions is called when the aie_timer expires. 513 */ 514 void rtc_aie_update_irq(void *private) 515 { 516 struct rtc_device *rtc = (struct rtc_device *)private; 517 rtc_handle_legacy_irq(rtc, 1, RTC_AF); 518 } 519 520 521 /** 522 * rtc_uie_update_irq - UIE mode rtctimer hook 523 * @private: pointer to the rtc_device 524 * 525 * This functions is called when the uie_timer expires. 526 */ 527 void rtc_uie_update_irq(void *private) 528 { 529 struct rtc_device *rtc = (struct rtc_device *)private; 530 rtc_handle_legacy_irq(rtc, 1, RTC_UF); 531 } 532 533 534 /** 535 * rtc_pie_update_irq - PIE mode hrtimer hook 536 * @timer: pointer to the pie mode hrtimer 537 * 538 * This function is used to emulate PIE mode interrupts 539 * using an hrtimer. This function is called when the periodic 540 * hrtimer expires. 541 */ 542 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer) 543 { 544 struct rtc_device *rtc; 545 ktime_t period; 546 int count; 547 rtc = container_of(timer, struct rtc_device, pie_timer); 548 549 period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq); 550 count = hrtimer_forward_now(timer, period); 551 552 rtc_handle_legacy_irq(rtc, count, RTC_PF); 553 554 return HRTIMER_RESTART; 555 } 556 557 /** 558 * rtc_update_irq - Triggered when a RTC interrupt occurs. 559 * @rtc: the rtc device 560 * @num: how many irqs are being reported (usually one) 561 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF 562 * Context: any 563 */ 564 void rtc_update_irq(struct rtc_device *rtc, 565 unsigned long num, unsigned long events) 566 { 567 schedule_work(&rtc->irqwork); 568 } 569 EXPORT_SYMBOL_GPL(rtc_update_irq); 570 571 static int __rtc_match(struct device *dev, void *data) 572 { 573 char *name = (char *)data; 574 575 if (strcmp(dev_name(dev), name) == 0) 576 return 1; 577 return 0; 578 } 579 580 struct rtc_device *rtc_class_open(char *name) 581 { 582 struct device *dev; 583 struct rtc_device *rtc = NULL; 584 585 dev = class_find_device(rtc_class, NULL, name, __rtc_match); 586 if (dev) 587 rtc = to_rtc_device(dev); 588 589 if (rtc) { 590 if (!try_module_get(rtc->owner)) { 591 put_device(dev); 592 rtc = NULL; 593 } 594 } 595 596 return rtc; 597 } 598 EXPORT_SYMBOL_GPL(rtc_class_open); 599 600 void rtc_class_close(struct rtc_device *rtc) 601 { 602 module_put(rtc->owner); 603 put_device(&rtc->dev); 604 } 605 EXPORT_SYMBOL_GPL(rtc_class_close); 606 607 int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task) 608 { 609 int retval = -EBUSY; 610 611 if (task == NULL || task->func == NULL) 612 return -EINVAL; 613 614 /* Cannot register while the char dev is in use */ 615 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags)) 616 return -EBUSY; 617 618 spin_lock_irq(&rtc->irq_task_lock); 619 if (rtc->irq_task == NULL) { 620 rtc->irq_task = task; 621 retval = 0; 622 } 623 spin_unlock_irq(&rtc->irq_task_lock); 624 625 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags); 626 627 return retval; 628 } 629 EXPORT_SYMBOL_GPL(rtc_irq_register); 630 631 void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task) 632 { 633 spin_lock_irq(&rtc->irq_task_lock); 634 if (rtc->irq_task == task) 635 rtc->irq_task = NULL; 636 spin_unlock_irq(&rtc->irq_task_lock); 637 } 638 EXPORT_SYMBOL_GPL(rtc_irq_unregister); 639 640 static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled) 641 { 642 /* 643 * We always cancel the timer here first, because otherwise 644 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK); 645 * when we manage to start the timer before the callback 646 * returns HRTIMER_RESTART. 647 * 648 * We cannot use hrtimer_cancel() here as a running callback 649 * could be blocked on rtc->irq_task_lock and hrtimer_cancel() 650 * would spin forever. 651 */ 652 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0) 653 return -1; 654 655 if (enabled) { 656 ktime_t period = ktime_set(0, NSEC_PER_SEC / rtc->irq_freq); 657 658 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL); 659 } 660 return 0; 661 } 662 663 /** 664 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs 665 * @rtc: the rtc device 666 * @task: currently registered with rtc_irq_register() 667 * @enabled: true to enable periodic IRQs 668 * Context: any 669 * 670 * Note that rtc_irq_set_freq() should previously have been used to 671 * specify the desired frequency of periodic IRQ task->func() callbacks. 672 */ 673 int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled) 674 { 675 int err = 0; 676 unsigned long flags; 677 678 retry: 679 spin_lock_irqsave(&rtc->irq_task_lock, flags); 680 if (rtc->irq_task != NULL && task == NULL) 681 err = -EBUSY; 682 if (rtc->irq_task != task) 683 err = -EACCES; 684 if (!err) { 685 if (rtc_update_hrtimer(rtc, enabled) < 0) { 686 spin_unlock_irqrestore(&rtc->irq_task_lock, flags); 687 cpu_relax(); 688 goto retry; 689 } 690 rtc->pie_enabled = enabled; 691 } 692 spin_unlock_irqrestore(&rtc->irq_task_lock, flags); 693 return err; 694 } 695 EXPORT_SYMBOL_GPL(rtc_irq_set_state); 696 697 /** 698 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ 699 * @rtc: the rtc device 700 * @task: currently registered with rtc_irq_register() 701 * @freq: positive frequency with which task->func() will be called 702 * Context: any 703 * 704 * Note that rtc_irq_set_state() is used to enable or disable the 705 * periodic IRQs. 706 */ 707 int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq) 708 { 709 int err = 0; 710 unsigned long flags; 711 712 if (freq <= 0 || freq > RTC_MAX_FREQ) 713 return -EINVAL; 714 retry: 715 spin_lock_irqsave(&rtc->irq_task_lock, flags); 716 if (rtc->irq_task != NULL && task == NULL) 717 err = -EBUSY; 718 if (rtc->irq_task != task) 719 err = -EACCES; 720 if (!err) { 721 rtc->irq_freq = freq; 722 if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) { 723 spin_unlock_irqrestore(&rtc->irq_task_lock, flags); 724 cpu_relax(); 725 goto retry; 726 } 727 } 728 spin_unlock_irqrestore(&rtc->irq_task_lock, flags); 729 return err; 730 } 731 EXPORT_SYMBOL_GPL(rtc_irq_set_freq); 732 733 /** 734 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue 735 * @rtc rtc device 736 * @timer timer being added. 737 * 738 * Enqueues a timer onto the rtc devices timerqueue and sets 739 * the next alarm event appropriately. 740 * 741 * Sets the enabled bit on the added timer. 742 * 743 * Must hold ops_lock for proper serialization of timerqueue 744 */ 745 static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer) 746 { 747 timer->enabled = 1; 748 timerqueue_add(&rtc->timerqueue, &timer->node); 749 if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) { 750 struct rtc_wkalrm alarm; 751 int err; 752 alarm.time = rtc_ktime_to_tm(timer->node.expires); 753 alarm.enabled = 1; 754 err = __rtc_set_alarm(rtc, &alarm); 755 if (err == -ETIME) 756 schedule_work(&rtc->irqwork); 757 else if (err) { 758 timerqueue_del(&rtc->timerqueue, &timer->node); 759 timer->enabled = 0; 760 return err; 761 } 762 } 763 return 0; 764 } 765 766 /** 767 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue 768 * @rtc rtc device 769 * @timer timer being removed. 770 * 771 * Removes a timer onto the rtc devices timerqueue and sets 772 * the next alarm event appropriately. 773 * 774 * Clears the enabled bit on the removed timer. 775 * 776 * Must hold ops_lock for proper serialization of timerqueue 777 */ 778 static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer) 779 { 780 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue); 781 timerqueue_del(&rtc->timerqueue, &timer->node); 782 timer->enabled = 0; 783 if (next == &timer->node) { 784 struct rtc_wkalrm alarm; 785 int err; 786 next = timerqueue_getnext(&rtc->timerqueue); 787 if (!next) 788 return; 789 alarm.time = rtc_ktime_to_tm(next->expires); 790 alarm.enabled = 1; 791 err = __rtc_set_alarm(rtc, &alarm); 792 if (err == -ETIME) 793 schedule_work(&rtc->irqwork); 794 } 795 } 796 797 /** 798 * rtc_timer_do_work - Expires rtc timers 799 * @rtc rtc device 800 * @timer timer being removed. 801 * 802 * Expires rtc timers. Reprograms next alarm event if needed. 803 * Called via worktask. 804 * 805 * Serializes access to timerqueue via ops_lock mutex 806 */ 807 void rtc_timer_do_work(struct work_struct *work) 808 { 809 struct rtc_timer *timer; 810 struct timerqueue_node *next; 811 ktime_t now; 812 struct rtc_time tm; 813 814 struct rtc_device *rtc = 815 container_of(work, struct rtc_device, irqwork); 816 817 mutex_lock(&rtc->ops_lock); 818 again: 819 __rtc_read_time(rtc, &tm); 820 now = rtc_tm_to_ktime(tm); 821 while ((next = timerqueue_getnext(&rtc->timerqueue))) { 822 if (next->expires.tv64 > now.tv64) 823 break; 824 825 /* expire timer */ 826 timer = container_of(next, struct rtc_timer, node); 827 timerqueue_del(&rtc->timerqueue, &timer->node); 828 timer->enabled = 0; 829 if (timer->task.func) 830 timer->task.func(timer->task.private_data); 831 832 /* Re-add/fwd periodic timers */ 833 if (ktime_to_ns(timer->period)) { 834 timer->node.expires = ktime_add(timer->node.expires, 835 timer->period); 836 timer->enabled = 1; 837 timerqueue_add(&rtc->timerqueue, &timer->node); 838 } 839 } 840 841 /* Set next alarm */ 842 if (next) { 843 struct rtc_wkalrm alarm; 844 int err; 845 alarm.time = rtc_ktime_to_tm(next->expires); 846 alarm.enabled = 1; 847 err = __rtc_set_alarm(rtc, &alarm); 848 if (err == -ETIME) 849 goto again; 850 } 851 852 mutex_unlock(&rtc->ops_lock); 853 } 854 855 856 /* rtc_timer_init - Initializes an rtc_timer 857 * @timer: timer to be intiialized 858 * @f: function pointer to be called when timer fires 859 * @data: private data passed to function pointer 860 * 861 * Kernel interface to initializing an rtc_timer. 862 */ 863 void rtc_timer_init(struct rtc_timer *timer, void (*f)(void* p), void* data) 864 { 865 timerqueue_init(&timer->node); 866 timer->enabled = 0; 867 timer->task.func = f; 868 timer->task.private_data = data; 869 } 870 871 /* rtc_timer_start - Sets an rtc_timer to fire in the future 872 * @ rtc: rtc device to be used 873 * @ timer: timer being set 874 * @ expires: time at which to expire the timer 875 * @ period: period that the timer will recur 876 * 877 * Kernel interface to set an rtc_timer 878 */ 879 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer* timer, 880 ktime_t expires, ktime_t period) 881 { 882 int ret = 0; 883 mutex_lock(&rtc->ops_lock); 884 if (timer->enabled) 885 rtc_timer_remove(rtc, timer); 886 887 timer->node.expires = expires; 888 timer->period = period; 889 890 ret = rtc_timer_enqueue(rtc, timer); 891 892 mutex_unlock(&rtc->ops_lock); 893 return ret; 894 } 895 896 /* rtc_timer_cancel - Stops an rtc_timer 897 * @ rtc: rtc device to be used 898 * @ timer: timer being set 899 * 900 * Kernel interface to cancel an rtc_timer 901 */ 902 int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer* timer) 903 { 904 int ret = 0; 905 mutex_lock(&rtc->ops_lock); 906 if (timer->enabled) 907 rtc_timer_remove(rtc, timer); 908 mutex_unlock(&rtc->ops_lock); 909 return ret; 910 } 911 912 913