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(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(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 time64_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(&rtc->ops_lock); 120 121 trace_rtc_read_time(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; 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 err = mutex_lock_interruptible(&rtc->ops_lock); 141 if (err) 142 return err; 143 144 if (!rtc->ops) 145 err = -ENODEV; 146 else if (rtc->ops->set_time) 147 err = rtc->ops->set_time(rtc->dev.parent, tm); 148 else if (rtc->ops->set_mmss64) 149 err = rtc->ops->set_mmss64(rtc->dev.parent, 150 rtc_tm_to_time64(tm)); 151 else if (rtc->ops->set_mmss) 152 err = rtc->ops->set_mmss(rtc->dev.parent, 153 rtc_tm_to_time64(tm)); 154 else 155 err = -EINVAL; 156 157 pm_stay_awake(rtc->dev.parent); 158 mutex_unlock(&rtc->ops_lock); 159 /* A timer might have just expired */ 160 schedule_work(&rtc->irqwork); 161 162 trace_rtc_set_time(rtc_tm_to_time64(tm), err); 163 return err; 164 } 165 EXPORT_SYMBOL_GPL(rtc_set_time); 166 167 static int rtc_read_alarm_internal(struct rtc_device *rtc, 168 struct rtc_wkalrm *alarm) 169 { 170 int err; 171 172 err = mutex_lock_interruptible(&rtc->ops_lock); 173 if (err) 174 return err; 175 176 if (!rtc->ops) { 177 err = -ENODEV; 178 } else if (!rtc->ops->read_alarm) { 179 err = -EINVAL; 180 } else { 181 alarm->enabled = 0; 182 alarm->pending = 0; 183 alarm->time.tm_sec = -1; 184 alarm->time.tm_min = -1; 185 alarm->time.tm_hour = -1; 186 alarm->time.tm_mday = -1; 187 alarm->time.tm_mon = -1; 188 alarm->time.tm_year = -1; 189 alarm->time.tm_wday = -1; 190 alarm->time.tm_yday = -1; 191 alarm->time.tm_isdst = -1; 192 err = rtc->ops->read_alarm(rtc->dev.parent, alarm); 193 } 194 195 mutex_unlock(&rtc->ops_lock); 196 197 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err); 198 return err; 199 } 200 201 int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 202 { 203 int err; 204 struct rtc_time before, now; 205 int first_time = 1; 206 time64_t t_now, t_alm; 207 enum { none, day, month, year } missing = none; 208 unsigned int days; 209 210 /* The lower level RTC driver may return -1 in some fields, 211 * creating invalid alarm->time values, for reasons like: 212 * 213 * - The hardware may not be capable of filling them in; 214 * many alarms match only on time-of-day fields, not 215 * day/month/year calendar data. 216 * 217 * - Some hardware uses illegal values as "wildcard" match 218 * values, which non-Linux firmware (like a BIOS) may try 219 * to set up as e.g. "alarm 15 minutes after each hour". 220 * Linux uses only oneshot alarms. 221 * 222 * When we see that here, we deal with it by using values from 223 * a current RTC timestamp for any missing (-1) values. The 224 * RTC driver prevents "periodic alarm" modes. 225 * 226 * But this can be racey, because some fields of the RTC timestamp 227 * may have wrapped in the interval since we read the RTC alarm, 228 * which would lead to us inserting inconsistent values in place 229 * of the -1 fields. 230 * 231 * Reading the alarm and timestamp in the reverse sequence 232 * would have the same race condition, and not solve the issue. 233 * 234 * So, we must first read the RTC timestamp, 235 * then read the RTC alarm value, 236 * and then read a second RTC timestamp. 237 * 238 * If any fields of the second timestamp have changed 239 * when compared with the first timestamp, then we know 240 * our timestamp may be inconsistent with that used by 241 * the low-level rtc_read_alarm_internal() function. 242 * 243 * So, when the two timestamps disagree, we just loop and do 244 * the process again to get a fully consistent set of values. 245 * 246 * This could all instead be done in the lower level driver, 247 * but since more than one lower level RTC implementation needs it, 248 * then it's probably best best to do it here instead of there.. 249 */ 250 251 /* Get the "before" timestamp */ 252 err = rtc_read_time(rtc, &before); 253 if (err < 0) 254 return err; 255 do { 256 if (!first_time) 257 memcpy(&before, &now, sizeof(struct rtc_time)); 258 first_time = 0; 259 260 /* get the RTC alarm values, which may be incomplete */ 261 err = rtc_read_alarm_internal(rtc, alarm); 262 if (err) 263 return err; 264 265 /* full-function RTCs won't have such missing fields */ 266 if (rtc_valid_tm(&alarm->time) == 0) { 267 rtc_add_offset(rtc, &alarm->time); 268 return 0; 269 } 270 271 /* get the "after" timestamp, to detect wrapped fields */ 272 err = rtc_read_time(rtc, &now); 273 if (err < 0) 274 return err; 275 276 /* note that tm_sec is a "don't care" value here: */ 277 } while (before.tm_min != now.tm_min || 278 before.tm_hour != now.tm_hour || 279 before.tm_mon != now.tm_mon || 280 before.tm_year != now.tm_year); 281 282 /* Fill in the missing alarm fields using the timestamp; we 283 * know there's at least one since alarm->time is invalid. 284 */ 285 if (alarm->time.tm_sec == -1) 286 alarm->time.tm_sec = now.tm_sec; 287 if (alarm->time.tm_min == -1) 288 alarm->time.tm_min = now.tm_min; 289 if (alarm->time.tm_hour == -1) 290 alarm->time.tm_hour = now.tm_hour; 291 292 /* For simplicity, only support date rollover for now */ 293 if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) { 294 alarm->time.tm_mday = now.tm_mday; 295 missing = day; 296 } 297 if ((unsigned int)alarm->time.tm_mon >= 12) { 298 alarm->time.tm_mon = now.tm_mon; 299 if (missing == none) 300 missing = month; 301 } 302 if (alarm->time.tm_year == -1) { 303 alarm->time.tm_year = now.tm_year; 304 if (missing == none) 305 missing = year; 306 } 307 308 /* Can't proceed if alarm is still invalid after replacing 309 * missing fields. 310 */ 311 err = rtc_valid_tm(&alarm->time); 312 if (err) 313 goto done; 314 315 /* with luck, no rollover is needed */ 316 t_now = rtc_tm_to_time64(&now); 317 t_alm = rtc_tm_to_time64(&alarm->time); 318 if (t_now < t_alm) 319 goto done; 320 321 switch (missing) { 322 /* 24 hour rollover ... if it's now 10am Monday, an alarm that 323 * that will trigger at 5am will do so at 5am Tuesday, which 324 * could also be in the next month or year. This is a common 325 * case, especially for PCs. 326 */ 327 case day: 328 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day"); 329 t_alm += 24 * 60 * 60; 330 rtc_time64_to_tm(t_alm, &alarm->time); 331 break; 332 333 /* Month rollover ... if it's the 31th, an alarm on the 3rd will 334 * be next month. An alarm matching on the 30th, 29th, or 28th 335 * may end up in the month after that! Many newer PCs support 336 * this type of alarm. 337 */ 338 case month: 339 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month"); 340 do { 341 if (alarm->time.tm_mon < 11) { 342 alarm->time.tm_mon++; 343 } else { 344 alarm->time.tm_mon = 0; 345 alarm->time.tm_year++; 346 } 347 days = rtc_month_days(alarm->time.tm_mon, 348 alarm->time.tm_year); 349 } while (days < alarm->time.tm_mday); 350 break; 351 352 /* Year rollover ... easy except for leap years! */ 353 case year: 354 dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year"); 355 do { 356 alarm->time.tm_year++; 357 } while (!is_leap_year(alarm->time.tm_year + 1900) && 358 rtc_valid_tm(&alarm->time) != 0); 359 break; 360 361 default: 362 dev_warn(&rtc->dev, "alarm rollover not handled\n"); 363 } 364 365 err = rtc_valid_tm(&alarm->time); 366 367 done: 368 if (err) 369 dev_warn(&rtc->dev, "invalid alarm value: %ptR\n", 370 &alarm->time); 371 372 return err; 373 } 374 375 int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 376 { 377 int err; 378 379 err = mutex_lock_interruptible(&rtc->ops_lock); 380 if (err) 381 return err; 382 if (!rtc->ops) { 383 err = -ENODEV; 384 } else if (!rtc->ops->read_alarm) { 385 err = -EINVAL; 386 } else { 387 memset(alarm, 0, sizeof(struct rtc_wkalrm)); 388 alarm->enabled = rtc->aie_timer.enabled; 389 alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires); 390 } 391 mutex_unlock(&rtc->ops_lock); 392 393 trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err); 394 return err; 395 } 396 EXPORT_SYMBOL_GPL(rtc_read_alarm); 397 398 static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 399 { 400 struct rtc_time tm; 401 time64_t now, scheduled; 402 int err; 403 404 err = rtc_valid_tm(&alarm->time); 405 if (err) 406 return err; 407 408 scheduled = rtc_tm_to_time64(&alarm->time); 409 410 /* Make sure we're not setting alarms in the past */ 411 err = __rtc_read_time(rtc, &tm); 412 if (err) 413 return err; 414 now = rtc_tm_to_time64(&tm); 415 if (scheduled <= now) 416 return -ETIME; 417 /* 418 * XXX - We just checked to make sure the alarm time is not 419 * in the past, but there is still a race window where if 420 * the is alarm set for the next second and the second ticks 421 * over right here, before we set the alarm. 422 */ 423 424 rtc_subtract_offset(rtc, &alarm->time); 425 426 if (!rtc->ops) 427 err = -ENODEV; 428 else if (!rtc->ops->set_alarm) 429 err = -EINVAL; 430 else 431 err = rtc->ops->set_alarm(rtc->dev.parent, alarm); 432 433 trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err); 434 return err; 435 } 436 437 int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 438 { 439 int err; 440 441 if (!rtc->ops) 442 return -ENODEV; 443 else if (!rtc->ops->set_alarm) 444 return -EINVAL; 445 446 err = rtc_valid_tm(&alarm->time); 447 if (err != 0) 448 return err; 449 450 err = rtc_valid_range(rtc, &alarm->time); 451 if (err) 452 return err; 453 454 err = mutex_lock_interruptible(&rtc->ops_lock); 455 if (err) 456 return err; 457 if (rtc->aie_timer.enabled) 458 rtc_timer_remove(rtc, &rtc->aie_timer); 459 460 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time); 461 rtc->aie_timer.period = 0; 462 if (alarm->enabled) 463 err = rtc_timer_enqueue(rtc, &rtc->aie_timer); 464 465 mutex_unlock(&rtc->ops_lock); 466 467 return err; 468 } 469 EXPORT_SYMBOL_GPL(rtc_set_alarm); 470 471 /* Called once per device from rtc_device_register */ 472 int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) 473 { 474 int err; 475 struct rtc_time now; 476 477 err = rtc_valid_tm(&alarm->time); 478 if (err != 0) 479 return err; 480 481 err = rtc_read_time(rtc, &now); 482 if (err) 483 return err; 484 485 err = mutex_lock_interruptible(&rtc->ops_lock); 486 if (err) 487 return err; 488 489 rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time); 490 rtc->aie_timer.period = 0; 491 492 /* Alarm has to be enabled & in the future for us to enqueue it */ 493 if (alarm->enabled && (rtc_tm_to_ktime(now) < 494 rtc->aie_timer.node.expires)) { 495 rtc->aie_timer.enabled = 1; 496 timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node); 497 trace_rtc_timer_enqueue(&rtc->aie_timer); 498 } 499 mutex_unlock(&rtc->ops_lock); 500 return err; 501 } 502 EXPORT_SYMBOL_GPL(rtc_initialize_alarm); 503 504 int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled) 505 { 506 int err; 507 508 err = mutex_lock_interruptible(&rtc->ops_lock); 509 if (err) 510 return err; 511 512 if (rtc->aie_timer.enabled != enabled) { 513 if (enabled) 514 err = rtc_timer_enqueue(rtc, &rtc->aie_timer); 515 else 516 rtc_timer_remove(rtc, &rtc->aie_timer); 517 } 518 519 if (err) 520 /* nothing */; 521 else if (!rtc->ops) 522 err = -ENODEV; 523 else if (!rtc->ops->alarm_irq_enable) 524 err = -EINVAL; 525 else 526 err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled); 527 528 mutex_unlock(&rtc->ops_lock); 529 530 trace_rtc_alarm_irq_enable(enabled, err); 531 return err; 532 } 533 EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable); 534 535 int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) 536 { 537 int err; 538 539 err = mutex_lock_interruptible(&rtc->ops_lock); 540 if (err) 541 return err; 542 543 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL 544 if (enabled == 0 && rtc->uie_irq_active) { 545 mutex_unlock(&rtc->ops_lock); 546 return rtc_dev_update_irq_enable_emul(rtc, 0); 547 } 548 #endif 549 /* make sure we're changing state */ 550 if (rtc->uie_rtctimer.enabled == enabled) 551 goto out; 552 553 if (rtc->uie_unsupported) { 554 err = -EINVAL; 555 goto out; 556 } 557 558 if (enabled) { 559 struct rtc_time tm; 560 ktime_t now, onesec; 561 562 __rtc_read_time(rtc, &tm); 563 onesec = ktime_set(1, 0); 564 now = rtc_tm_to_ktime(tm); 565 rtc->uie_rtctimer.node.expires = ktime_add(now, onesec); 566 rtc->uie_rtctimer.period = ktime_set(1, 0); 567 err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer); 568 } else { 569 rtc_timer_remove(rtc, &rtc->uie_rtctimer); 570 } 571 572 out: 573 mutex_unlock(&rtc->ops_lock); 574 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL 575 /* 576 * Enable emulation if the driver returned -EINVAL to signal that it has 577 * been configured without interrupts or they are not available at the 578 * moment. 579 */ 580 if (err == -EINVAL) 581 err = rtc_dev_update_irq_enable_emul(rtc, enabled); 582 #endif 583 return err; 584 } 585 EXPORT_SYMBOL_GPL(rtc_update_irq_enable); 586 587 /** 588 * rtc_handle_legacy_irq - AIE, UIE and PIE event hook 589 * @rtc: pointer to the rtc device 590 * 591 * This function is called when an AIE, UIE or PIE mode interrupt 592 * has occurred (or been emulated). 593 * 594 */ 595 void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode) 596 { 597 unsigned long flags; 598 599 /* mark one irq of the appropriate mode */ 600 spin_lock_irqsave(&rtc->irq_lock, flags); 601 rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF | mode); 602 spin_unlock_irqrestore(&rtc->irq_lock, flags); 603 604 wake_up_interruptible(&rtc->irq_queue); 605 kill_fasync(&rtc->async_queue, SIGIO, POLL_IN); 606 } 607 608 /** 609 * rtc_aie_update_irq - AIE mode rtctimer hook 610 * @rtc: pointer to the rtc_device 611 * 612 * This functions is called when the aie_timer expires. 613 */ 614 void rtc_aie_update_irq(struct rtc_device *rtc) 615 { 616 rtc_handle_legacy_irq(rtc, 1, RTC_AF); 617 } 618 619 /** 620 * rtc_uie_update_irq - UIE mode rtctimer hook 621 * @rtc: pointer to the rtc_device 622 * 623 * This functions is called when the uie_timer expires. 624 */ 625 void rtc_uie_update_irq(struct rtc_device *rtc) 626 { 627 rtc_handle_legacy_irq(rtc, 1, RTC_UF); 628 } 629 630 /** 631 * rtc_pie_update_irq - PIE mode hrtimer hook 632 * @timer: pointer to the pie mode hrtimer 633 * 634 * This function is used to emulate PIE mode interrupts 635 * using an hrtimer. This function is called when the periodic 636 * hrtimer expires. 637 */ 638 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer) 639 { 640 struct rtc_device *rtc; 641 ktime_t period; 642 int count; 643 644 rtc = container_of(timer, struct rtc_device, pie_timer); 645 646 period = NSEC_PER_SEC / rtc->irq_freq; 647 count = hrtimer_forward_now(timer, period); 648 649 rtc_handle_legacy_irq(rtc, count, RTC_PF); 650 651 return HRTIMER_RESTART; 652 } 653 654 /** 655 * rtc_update_irq - Triggered when a RTC interrupt occurs. 656 * @rtc: the rtc device 657 * @num: how many irqs are being reported (usually one) 658 * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF 659 * Context: any 660 */ 661 void rtc_update_irq(struct rtc_device *rtc, 662 unsigned long num, unsigned long events) 663 { 664 if (IS_ERR_OR_NULL(rtc)) 665 return; 666 667 pm_stay_awake(rtc->dev.parent); 668 schedule_work(&rtc->irqwork); 669 } 670 EXPORT_SYMBOL_GPL(rtc_update_irq); 671 672 static int __rtc_match(struct device *dev, const void *data) 673 { 674 const char *name = data; 675 676 if (strcmp(dev_name(dev), name) == 0) 677 return 1; 678 return 0; 679 } 680 681 struct rtc_device *rtc_class_open(const char *name) 682 { 683 struct device *dev; 684 struct rtc_device *rtc = NULL; 685 686 dev = class_find_device(rtc_class, NULL, name, __rtc_match); 687 if (dev) 688 rtc = to_rtc_device(dev); 689 690 if (rtc) { 691 if (!try_module_get(rtc->owner)) { 692 put_device(dev); 693 rtc = NULL; 694 } 695 } 696 697 return rtc; 698 } 699 EXPORT_SYMBOL_GPL(rtc_class_open); 700 701 void rtc_class_close(struct rtc_device *rtc) 702 { 703 module_put(rtc->owner); 704 put_device(&rtc->dev); 705 } 706 EXPORT_SYMBOL_GPL(rtc_class_close); 707 708 static int rtc_update_hrtimer(struct rtc_device *rtc, int enabled) 709 { 710 /* 711 * We always cancel the timer here first, because otherwise 712 * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK); 713 * when we manage to start the timer before the callback 714 * returns HRTIMER_RESTART. 715 * 716 * We cannot use hrtimer_cancel() here as a running callback 717 * could be blocked on rtc->irq_task_lock and hrtimer_cancel() 718 * would spin forever. 719 */ 720 if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0) 721 return -1; 722 723 if (enabled) { 724 ktime_t period = NSEC_PER_SEC / rtc->irq_freq; 725 726 hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL); 727 } 728 return 0; 729 } 730 731 /** 732 * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs 733 * @rtc: the rtc device 734 * @enabled: true to enable periodic IRQs 735 * Context: any 736 * 737 * Note that rtc_irq_set_freq() should previously have been used to 738 * specify the desired frequency of periodic IRQ. 739 */ 740 int rtc_irq_set_state(struct rtc_device *rtc, int enabled) 741 { 742 int err = 0; 743 744 while (rtc_update_hrtimer(rtc, enabled) < 0) 745 cpu_relax(); 746 747 rtc->pie_enabled = enabled; 748 749 trace_rtc_irq_set_state(enabled, err); 750 return err; 751 } 752 753 /** 754 * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ 755 * @rtc: the rtc device 756 * @freq: positive frequency 757 * Context: any 758 * 759 * Note that rtc_irq_set_state() is used to enable or disable the 760 * periodic IRQs. 761 */ 762 int rtc_irq_set_freq(struct rtc_device *rtc, int freq) 763 { 764 int err = 0; 765 766 if (freq <= 0 || freq > RTC_MAX_FREQ) 767 return -EINVAL; 768 769 rtc->irq_freq = freq; 770 while (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) 771 cpu_relax(); 772 773 trace_rtc_irq_set_freq(freq, err); 774 return err; 775 } 776 777 /** 778 * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue 779 * @rtc rtc device 780 * @timer timer being added. 781 * 782 * Enqueues a timer onto the rtc devices timerqueue and sets 783 * the next alarm event appropriately. 784 * 785 * Sets the enabled bit on the added timer. 786 * 787 * Must hold ops_lock for proper serialization of timerqueue 788 */ 789 static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer) 790 { 791 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue); 792 struct rtc_time tm; 793 ktime_t now; 794 795 timer->enabled = 1; 796 __rtc_read_time(rtc, &tm); 797 now = rtc_tm_to_ktime(tm); 798 799 /* Skip over expired timers */ 800 while (next) { 801 if (next->expires >= now) 802 break; 803 next = timerqueue_iterate_next(next); 804 } 805 806 timerqueue_add(&rtc->timerqueue, &timer->node); 807 trace_rtc_timer_enqueue(timer); 808 if (!next || ktime_before(timer->node.expires, next->expires)) { 809 struct rtc_wkalrm alarm; 810 int err; 811 812 alarm.time = rtc_ktime_to_tm(timer->node.expires); 813 alarm.enabled = 1; 814 err = __rtc_set_alarm(rtc, &alarm); 815 if (err == -ETIME) { 816 pm_stay_awake(rtc->dev.parent); 817 schedule_work(&rtc->irqwork); 818 } else if (err) { 819 timerqueue_del(&rtc->timerqueue, &timer->node); 820 trace_rtc_timer_dequeue(timer); 821 timer->enabled = 0; 822 return err; 823 } 824 } 825 return 0; 826 } 827 828 static void rtc_alarm_disable(struct rtc_device *rtc) 829 { 830 if (!rtc->ops || !rtc->ops->alarm_irq_enable) 831 return; 832 833 rtc->ops->alarm_irq_enable(rtc->dev.parent, false); 834 trace_rtc_alarm_irq_enable(0, 0); 835 } 836 837 /** 838 * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue 839 * @rtc rtc device 840 * @timer timer being removed. 841 * 842 * Removes a timer onto the rtc devices timerqueue and sets 843 * the next alarm event appropriately. 844 * 845 * Clears the enabled bit on the removed timer. 846 * 847 * Must hold ops_lock for proper serialization of timerqueue 848 */ 849 static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer) 850 { 851 struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue); 852 853 timerqueue_del(&rtc->timerqueue, &timer->node); 854 trace_rtc_timer_dequeue(timer); 855 timer->enabled = 0; 856 if (next == &timer->node) { 857 struct rtc_wkalrm alarm; 858 int err; 859 860 next = timerqueue_getnext(&rtc->timerqueue); 861 if (!next) { 862 rtc_alarm_disable(rtc); 863 return; 864 } 865 alarm.time = rtc_ktime_to_tm(next->expires); 866 alarm.enabled = 1; 867 err = __rtc_set_alarm(rtc, &alarm); 868 if (err == -ETIME) { 869 pm_stay_awake(rtc->dev.parent); 870 schedule_work(&rtc->irqwork); 871 } 872 } 873 } 874 875 /** 876 * rtc_timer_do_work - Expires rtc timers 877 * @rtc rtc device 878 * @timer timer being removed. 879 * 880 * Expires rtc timers. Reprograms next alarm event if needed. 881 * Called via worktask. 882 * 883 * Serializes access to timerqueue via ops_lock mutex 884 */ 885 void rtc_timer_do_work(struct work_struct *work) 886 { 887 struct rtc_timer *timer; 888 struct timerqueue_node *next; 889 ktime_t now; 890 struct rtc_time tm; 891 892 struct rtc_device *rtc = 893 container_of(work, struct rtc_device, irqwork); 894 895 mutex_lock(&rtc->ops_lock); 896 again: 897 __rtc_read_time(rtc, &tm); 898 now = rtc_tm_to_ktime(tm); 899 while ((next = timerqueue_getnext(&rtc->timerqueue))) { 900 if (next->expires > now) 901 break; 902 903 /* expire timer */ 904 timer = container_of(next, struct rtc_timer, node); 905 timerqueue_del(&rtc->timerqueue, &timer->node); 906 trace_rtc_timer_dequeue(timer); 907 timer->enabled = 0; 908 if (timer->func) 909 timer->func(timer->rtc); 910 911 trace_rtc_timer_fired(timer); 912 /* Re-add/fwd periodic timers */ 913 if (ktime_to_ns(timer->period)) { 914 timer->node.expires = ktime_add(timer->node.expires, 915 timer->period); 916 timer->enabled = 1; 917 timerqueue_add(&rtc->timerqueue, &timer->node); 918 trace_rtc_timer_enqueue(timer); 919 } 920 } 921 922 /* Set next alarm */ 923 if (next) { 924 struct rtc_wkalrm alarm; 925 int err; 926 int retry = 3; 927 928 alarm.time = rtc_ktime_to_tm(next->expires); 929 alarm.enabled = 1; 930 reprogram: 931 err = __rtc_set_alarm(rtc, &alarm); 932 if (err == -ETIME) { 933 goto again; 934 } else if (err) { 935 if (retry-- > 0) 936 goto reprogram; 937 938 timer = container_of(next, struct rtc_timer, node); 939 timerqueue_del(&rtc->timerqueue, &timer->node); 940 trace_rtc_timer_dequeue(timer); 941 timer->enabled = 0; 942 dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err); 943 goto again; 944 } 945 } else { 946 rtc_alarm_disable(rtc); 947 } 948 949 pm_relax(rtc->dev.parent); 950 mutex_unlock(&rtc->ops_lock); 951 } 952 953 /* rtc_timer_init - Initializes an rtc_timer 954 * @timer: timer to be intiialized 955 * @f: function pointer to be called when timer fires 956 * @rtc: pointer to the rtc_device 957 * 958 * Kernel interface to initializing an rtc_timer. 959 */ 960 void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r), 961 struct rtc_device *rtc) 962 { 963 timerqueue_init(&timer->node); 964 timer->enabled = 0; 965 timer->func = f; 966 timer->rtc = rtc; 967 } 968 969 /* rtc_timer_start - Sets an rtc_timer to fire in the future 970 * @ rtc: rtc device to be used 971 * @ timer: timer being set 972 * @ expires: time at which to expire the timer 973 * @ period: period that the timer will recur 974 * 975 * Kernel interface to set an rtc_timer 976 */ 977 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer, 978 ktime_t expires, ktime_t period) 979 { 980 int ret = 0; 981 982 mutex_lock(&rtc->ops_lock); 983 if (timer->enabled) 984 rtc_timer_remove(rtc, timer); 985 986 timer->node.expires = expires; 987 timer->period = period; 988 989 ret = rtc_timer_enqueue(rtc, timer); 990 991 mutex_unlock(&rtc->ops_lock); 992 return ret; 993 } 994 995 /* rtc_timer_cancel - Stops an rtc_timer 996 * @ rtc: rtc device to be used 997 * @ timer: timer being set 998 * 999 * Kernel interface to cancel an rtc_timer 1000 */ 1001 void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer) 1002 { 1003 mutex_lock(&rtc->ops_lock); 1004 if (timer->enabled) 1005 rtc_timer_remove(rtc, timer); 1006 mutex_unlock(&rtc->ops_lock); 1007 } 1008 1009 /** 1010 * rtc_read_offset - Read the amount of rtc offset in parts per billion 1011 * @ rtc: rtc device to be used 1012 * @ offset: the offset in parts per billion 1013 * 1014 * see below for details. 1015 * 1016 * Kernel interface to read rtc clock offset 1017 * Returns 0 on success, or a negative number on error. 1018 * If read_offset() is not implemented for the rtc, return -EINVAL 1019 */ 1020 int rtc_read_offset(struct rtc_device *rtc, long *offset) 1021 { 1022 int ret; 1023 1024 if (!rtc->ops) 1025 return -ENODEV; 1026 1027 if (!rtc->ops->read_offset) 1028 return -EINVAL; 1029 1030 mutex_lock(&rtc->ops_lock); 1031 ret = rtc->ops->read_offset(rtc->dev.parent, offset); 1032 mutex_unlock(&rtc->ops_lock); 1033 1034 trace_rtc_read_offset(*offset, ret); 1035 return ret; 1036 } 1037 1038 /** 1039 * rtc_set_offset - Adjusts the duration of the average second 1040 * @ rtc: rtc device to be used 1041 * @ offset: the offset in parts per billion 1042 * 1043 * Some rtc's allow an adjustment to the average duration of a second 1044 * to compensate for differences in the actual clock rate due to temperature, 1045 * the crystal, capacitor, etc. 1046 * 1047 * The adjustment applied is as follows: 1048 * t = t0 * (1 + offset * 1e-9) 1049 * where t0 is the measured length of 1 RTC second with offset = 0 1050 * 1051 * Kernel interface to adjust an rtc clock offset. 1052 * Return 0 on success, or a negative number on error. 1053 * If the rtc offset is not setable (or not implemented), return -EINVAL 1054 */ 1055 int rtc_set_offset(struct rtc_device *rtc, long offset) 1056 { 1057 int ret; 1058 1059 if (!rtc->ops) 1060 return -ENODEV; 1061 1062 if (!rtc->ops->set_offset) 1063 return -EINVAL; 1064 1065 mutex_lock(&rtc->ops_lock); 1066 ret = rtc->ops->set_offset(rtc->dev.parent, offset); 1067 mutex_unlock(&rtc->ops_lock); 1068 1069 trace_rtc_set_offset(offset, ret); 1070 return ret; 1071 } 1072