kernel/time/alarmtimer.c

   1 /*
   2  * Alarmtimer interface
   3  *
   4  * This interface provides a timer which is similarto hrtimers,
   5  * but triggers a RTC alarm if the box is suspend.
   6  *
   7  * This interface is influenced by the Android RTC Alarm timer
   8  * interface.
   9  *
  10  * Copyright (C) 2010 IBM Corperation
  11  *
  12  * Author: John Stultz <john.stultz@linaro.org>
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License version 2 as
  16  * published by the Free Software Foundation.
  17  */
  18 #include <linux/time.h>
  19 #include <linux/hrtimer.h>
  20 #include <linux/timerqueue.h>
  21 #include <linux/rtc.h>
  22 #include <linux/sched/signal.h>
  23 #include <linux/sched/debug.h>
  24 #include <linux/alarmtimer.h>
  25 #include <linux/mutex.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/posix-timers.h>
  28 #include <linux/workqueue.h>
  29 #include <linux/freezer.h>
  30 #include <linux/compat.h>
  31
  32 #include "posix-timers.h"
  33
  34 #define CREATE_TRACE_POINTS
  35 #include <trace/events/alarmtimer.h>
  36
  37 /**
  38  * struct alarm_base - Alarm timer bases
  39  * @lock:               Lock for syncrhonized access to the base
  40  * @timerqueue:         Timerqueue head managing the list of events
  41  * @gettime:            Function to read the time correlating to the base
  42  * @base_clockid:       clockid for the base
  43  */
  44 static struct alarm_base {
  45         spinlock_t              lock;
  46         struct timerqueue_head  timerqueue;
  47         ktime_t                 (*gettime)(void);
  48         clockid_t               base_clockid;
  49 } alarm_bases[ALARM_NUMTYPE];
  50
  51 #if defined(CONFIG_POSIX_TIMERS) || defined(CONFIG_RTC_CLASS)
  52 /* freezer information to handle clock_nanosleep triggered wakeups */
  53 static enum alarmtimer_type freezer_alarmtype;
  54 static ktime_t freezer_expires;
  55 static ktime_t freezer_delta;
  56 static DEFINE_SPINLOCK(freezer_delta_lock);
  57 #endif
  58
  59 static struct wakeup_source *ws;
  60
  61 #ifdef CONFIG_RTC_CLASS
  62 /* rtc timer and device for setting alarm wakeups at suspend */
  63 static struct rtc_timer         rtctimer;
  64 static struct rtc_device        *rtcdev;
  65 static DEFINE_SPINLOCK(rtcdev_lock);
  66
  67 /**
  68  * alarmtimer_get_rtcdev - Return selected rtcdevice
  69  *
  70  * This function returns the rtc device to use for wakealarms.
  71  * If one has not already been chosen, it checks to see if a
  72  * functional rtc device is available.
  73  */
  74 struct rtc_device *alarmtimer_get_rtcdev(void)
  75 {
  76         unsigned long flags;
  77         struct rtc_device *ret;
  78
  79         spin_lock_irqsave(&rtcdev_lock, flags);
  80         ret = rtcdev;
  81         spin_unlock_irqrestore(&rtcdev_lock, flags);
  82
  83         return ret;
  84 }
  85 EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev);
  86
  87 static int alarmtimer_rtc_add_device(struct device *dev,
  88                                 struct class_interface *class_intf)
  89 {
  90         unsigned long flags;
  91         struct rtc_device *rtc = to_rtc_device(dev);
  92
  93         if (rtcdev)
  94                 return -EBUSY;
  95
  96         if (!rtc->ops->set_alarm)
  97                 return -1;
  98         if (!device_may_wakeup(rtc->dev.parent))
  99                 return -1;
 100
 101         spin_lock_irqsave(&rtcdev_lock, flags);
 102         if (!rtcdev) {
 103                 rtcdev = rtc;
 104                 /* hold a reference so it doesn't go away */
 105                 get_device(dev);
 106         }
 107         spin_unlock_irqrestore(&rtcdev_lock, flags);
 108         return 0;
 109 }
 110
 111 static inline void alarmtimer_rtc_timer_init(void)
 112 {
 113         rtc_timer_init(&rtctimer, NULL, NULL);
 114 }
 115
 116 static struct class_interface alarmtimer_rtc_interface = {
 117         .add_dev = &alarmtimer_rtc_add_device,
 118 };
 119
 120 static int alarmtimer_rtc_interface_setup(void)
 121 {
 122         alarmtimer_rtc_interface.class = rtc_class;
 123         return class_interface_register(&alarmtimer_rtc_interface);
 124 }
 125 static void alarmtimer_rtc_interface_remove(void)
 126 {
 127         class_interface_unregister(&alarmtimer_rtc_interface);
 128 }
 129 #else
 130 struct rtc_device *alarmtimer_get_rtcdev(void)
 131 {
 132         return NULL;
 133 }
 134 #define rtcdev (NULL)
 135 static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
 136 static inline void alarmtimer_rtc_interface_remove(void) { }
 137 static inline void alarmtimer_rtc_timer_init(void) { }
 138 #endif
 139
 140 /**
 141  * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
 142  * @base: pointer to the base where the timer is being run
 143  * @alarm: pointer to alarm being enqueued.
 144  *
 145  * Adds alarm to a alarm_base timerqueue
 146  *
 147  * Must hold base->lock when calling.
 148  */
 149 static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
 150 {
 151         if (alarm->state & ALARMTIMER_STATE_ENQUEUED)
 152                 timerqueue_del(&base->timerqueue, &alarm->node);
 153
 154         timerqueue_add(&base->timerqueue, &alarm->node);
 155         alarm->state |= ALARMTIMER_STATE_ENQUEUED;
 156 }
 157
 158 /**
 159  * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue
 160  * @base: pointer to the base where the timer is running
 161  * @alarm: pointer to alarm being removed
 162  *
 163  * Removes alarm to a alarm_base timerqueue
 164  *
 165  * Must hold base->lock when calling.
 166  */
 167 static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm)
 168 {
 169         if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
 170                 return;
 171
 172         timerqueue_del(&base->timerqueue, &alarm->node);
 173         alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
 174 }
 175
 176
 177 /**
 178  * alarmtimer_fired - Handles alarm hrtimer being fired.
 179  * @timer: pointer to hrtimer being run
 180  *
 181  * When a alarm timer fires, this runs through the timerqueue to
 182  * see which alarms expired, and runs those. If there are more alarm
 183  * timers queued for the future, we set the hrtimer to fire when
 184  * when the next future alarm timer expires.
 185  */
 186 static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
 187 {
 188         struct alarm *alarm = container_of(timer, struct alarm, timer);
 189         struct alarm_base *base = &alarm_bases[alarm->type];
 190         unsigned long flags;
 191         int ret = HRTIMER_NORESTART;
 192         int restart = ALARMTIMER_NORESTART;
 193
 194         spin_lock_irqsave(&base->lock, flags);
 195         alarmtimer_dequeue(base, alarm);
 196         spin_unlock_irqrestore(&base->lock, flags);
 197
 198         if (alarm->function)
 199                 restart = alarm->function(alarm, base->gettime());
 200
 201         spin_lock_irqsave(&base->lock, flags);
 202         if (restart != ALARMTIMER_NORESTART) {
 203                 hrtimer_set_expires(&alarm->timer, alarm->node.expires);
 204                 alarmtimer_enqueue(base, alarm);
 205                 ret = HRTIMER_RESTART;
 206         }
 207         spin_unlock_irqrestore(&base->lock, flags);
 208
 209         trace_alarmtimer_fired(alarm, base->gettime());
 210         return ret;
 211
 212 }
 213
 214 ktime_t alarm_expires_remaining(const struct alarm *alarm)
 215 {
 216         struct alarm_base *base = &alarm_bases[alarm->type];
 217         return ktime_sub(alarm->node.expires, base->gettime());
 218 }
 219 EXPORT_SYMBOL_GPL(alarm_expires_remaining);
 220
 221 #ifdef CONFIG_RTC_CLASS
 222 /**
 223  * alarmtimer_suspend - Suspend time callback
 224  * @dev: unused
 225  * @state: unused
 226  *
 227  * When we are going into suspend, we look through the bases
 228  * to see which is the soonest timer to expire. We then
 229  * set an rtc timer to fire that far into the future, which
 230  * will wake us from suspend.
 231  */
 232 static int alarmtimer_suspend(struct device *dev)
 233 {
 234         ktime_t min, now, expires;
 235         int i, ret, type;
 236         struct rtc_device *rtc;
 237         unsigned long flags;
 238         struct rtc_time tm;
 239
 240         spin_lock_irqsave(&freezer_delta_lock, flags);
 241         min = freezer_delta;
 242         expires = freezer_expires;
 243         type = freezer_alarmtype;
 244         freezer_delta = 0;
 245         spin_unlock_irqrestore(&freezer_delta_lock, flags);
 246
 247         rtc = alarmtimer_get_rtcdev();
 248         /* If we have no rtcdev, just return */
 249         if (!rtc)
 250                 return 0;
 251
 252         /* Find the soonest timer to expire*/
 253         for (i = 0; i < ALARM_NUMTYPE; i++) {
 254                 struct alarm_base *base = &alarm_bases[i];
 255                 struct timerqueue_node *next;
 256                 ktime_t delta;
 257
 258                 spin_lock_irqsave(&base->lock, flags);
 259                 next = timerqueue_getnext(&base->timerqueue);
 260                 spin_unlock_irqrestore(&base->lock, flags);
 261                 if (!next)
 262                         continue;
 263                 delta = ktime_sub(next->expires, base->gettime());
 264                 if (!min || (delta < min)) {
 265                         expires = next->expires;
 266                         min = delta;
 267                         type = i;
 268                 }
 269         }
 270         if (min == 0)
 271                 return 0;
 272
 273         if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) {
 274                 __pm_wakeup_event(ws, 2 * MSEC_PER_SEC);
 275                 return -EBUSY;
 276         }
 277
 278         trace_alarmtimer_suspend(expires, type);
 279
 280         /* Setup an rtc timer to fire that far in the future */
 281         rtc_timer_cancel(rtc, &rtctimer);
 282         rtc_read_time(rtc, &tm);
 283         now = rtc_tm_to_ktime(tm);
 284         now = ktime_add(now, min);
 285
 286         /* Set alarm, if in the past reject suspend briefly to handle */
 287         ret = rtc_timer_start(rtc, &rtctimer, now, 0);
 288         if (ret < 0)
 289                 __pm_wakeup_event(ws, MSEC_PER_SEC);
 290         return ret;
 291 }
 292
 293 static int alarmtimer_resume(struct device *dev)
 294 {
 295         struct rtc_device *rtc;
 296
 297         rtc = alarmtimer_get_rtcdev();
 298         if (rtc)
 299                 rtc_timer_cancel(rtc, &rtctimer);
 300         return 0;
 301 }
 302
 303 #else
 304 static int alarmtimer_suspend(struct device *dev)
 305 {
 306         return 0;
 307 }
 308
 309 static int alarmtimer_resume(struct device *dev)
 310 {
 311         return 0;
 312 }
 313 #endif
 314
 315 /**
 316  * alarm_init - Initialize an alarm structure
 317  * @alarm: ptr to alarm to be initialized
 318  * @type: the type of the alarm
 319  * @function: callback that is run when the alarm fires
 320  */
 321 void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
 322                 enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
 323 {
 324         timerqueue_init(&alarm->node);
 325         hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid,
 326                         HRTIMER_MODE_ABS);
 327         alarm->timer.function = alarmtimer_fired;
 328         alarm->function = function;
 329         alarm->type = type;
 330         alarm->state = ALARMTIMER_STATE_INACTIVE;
 331 }
 332 EXPORT_SYMBOL_GPL(alarm_init);
 333
 334 /**
 335  * alarm_start - Sets an absolute alarm to fire
 336  * @alarm: ptr to alarm to set
 337  * @start: time to run the alarm
 338  */
 339 void alarm_start(struct alarm *alarm, ktime_t start)
 340 {
 341         struct alarm_base *base = &alarm_bases[alarm->type];
 342         unsigned long flags;
 343
 344         spin_lock_irqsave(&base->lock, flags);
 345         alarm->node.expires = start;
 346         alarmtimer_enqueue(base, alarm);
 347         hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS);
 348         spin_unlock_irqrestore(&base->lock, flags);
 349
 350         trace_alarmtimer_start(alarm, base->gettime());
 351 }
 352 EXPORT_SYMBOL_GPL(alarm_start);
 353
 354 /**
 355  * alarm_start_relative - Sets a relative alarm to fire
 356  * @alarm: ptr to alarm to set
 357  * @start: time relative to now to run the alarm
 358  */
 359 void alarm_start_relative(struct alarm *alarm, ktime_t start)
 360 {
 361         struct alarm_base *base = &alarm_bases[alarm->type];
 362
 363         start = ktime_add_safe(start, base->gettime());
 364         alarm_start(alarm, start);
 365 }
 366 EXPORT_SYMBOL_GPL(alarm_start_relative);
 367
 368 void alarm_restart(struct alarm *alarm)
 369 {
 370         struct alarm_base *base = &alarm_bases[alarm->type];
 371         unsigned long flags;
 372
 373         spin_lock_irqsave(&base->lock, flags);
 374         hrtimer_set_expires(&alarm->timer, alarm->node.expires);
 375         hrtimer_restart(&alarm->timer);
 376         alarmtimer_enqueue(base, alarm);
 377         spin_unlock_irqrestore(&base->lock, flags);
 378 }
 379 EXPORT_SYMBOL_GPL(alarm_restart);
 380
 381 /**
 382  * alarm_try_to_cancel - Tries to cancel an alarm timer
 383  * @alarm: ptr to alarm to be canceled
 384  *
 385  * Returns 1 if the timer was canceled, 0 if it was not running,
 386  * and -1 if the callback was running
 387  */
 388 int alarm_try_to_cancel(struct alarm *alarm)
 389 {
 390         struct alarm_base *base = &alarm_bases[alarm->type];
 391         unsigned long flags;
 392         int ret;
 393
 394         spin_lock_irqsave(&base->lock, flags);
 395         ret = hrtimer_try_to_cancel(&alarm->timer);
 396         if (ret >= 0)
 397                 alarmtimer_dequeue(base, alarm);
 398         spin_unlock_irqrestore(&base->lock, flags);
 399
 400         trace_alarmtimer_cancel(alarm, base->gettime());
 401         return ret;
 402 }
 403 EXPORT_SYMBOL_GPL(alarm_try_to_cancel);
 404
 405
 406 /**
 407  * alarm_cancel - Spins trying to cancel an alarm timer until it is done
 408  * @alarm: ptr to alarm to be canceled
 409  *
 410  * Returns 1 if the timer was canceled, 0 if it was not active.
 411  */
 412 int alarm_cancel(struct alarm *alarm)
 413 {
 414         for (;;) {
 415                 int ret = alarm_try_to_cancel(alarm);
 416                 if (ret >= 0)
 417                         return ret;
 418                 cpu_relax();
 419         }
 420 }
 421 EXPORT_SYMBOL_GPL(alarm_cancel);
 422
 423
 424 u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
 425 {
 426         u64 overrun = 1;
 427         ktime_t delta;
 428
 429         delta = ktime_sub(now, alarm->node.expires);
 430
 431         if (delta < 0)
 432                 return 0;
 433
 434         if (unlikely(delta >= interval)) {
 435                 s64 incr = ktime_to_ns(interval);
 436
 437                 overrun = ktime_divns(delta, incr);
 438
 439                 alarm->node.expires = ktime_add_ns(alarm->node.expires,
 440                                                         incr*overrun);
 441
 442                 if (alarm->node.expires > now)
 443                         return overrun;
 444                 /*
 445                  * This (and the ktime_add() below) is the
 446                  * correction for exact:
 447                  */
 448                 overrun++;
 449         }
 450
 451         alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
 452         return overrun;
 453 }
 454 EXPORT_SYMBOL_GPL(alarm_forward);
 455
 456 u64 alarm_forward_now(struct alarm *alarm, ktime_t interval)
 457 {
 458         struct alarm_base *base = &alarm_bases[alarm->type];
 459
 460         return alarm_forward(alarm, base->gettime(), interval);
 461 }
 462 EXPORT_SYMBOL_GPL(alarm_forward_now);
 463
 464 #ifdef CONFIG_POSIX_TIMERS
 465
 466 static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
 467 {
 468         struct alarm_base *base;
 469         unsigned long flags;
 470         ktime_t delta;
 471
 472         switch(type) {
 473         case ALARM_REALTIME:
 474                 base = &alarm_bases[ALARM_REALTIME];
 475                 type = ALARM_REALTIME_FREEZER;
 476                 break;
 477         case ALARM_BOOTTIME:
 478                 base = &alarm_bases[ALARM_BOOTTIME];
 479                 type = ALARM_BOOTTIME_FREEZER;
 480                 break;
 481         default:
 482                 WARN_ONCE(1, "Invalid alarm type: %d\n", type);
 483                 return;
 484         }
 485
 486         delta = ktime_sub(absexp, base->gettime());
 487
 488         spin_lock_irqsave(&freezer_delta_lock, flags);
 489         if (!freezer_delta || (delta < freezer_delta)) {
 490                 freezer_delta = delta;
 491                 freezer_expires = absexp;
 492                 freezer_alarmtype = type;
 493         }
 494         spin_unlock_irqrestore(&freezer_delta_lock, flags);
 495 }
 496
 497 /**
 498  * clock2alarm - helper that converts from clockid to alarmtypes
 499  * @clockid: clockid.
 500  */
 501 static enum alarmtimer_type clock2alarm(clockid_t clockid)
 502 {
 503         if (clockid == CLOCK_REALTIME_ALARM)
 504                 return ALARM_REALTIME;
 505         if (clockid == CLOCK_BOOTTIME_ALARM)
 506                 return ALARM_BOOTTIME;
 507         return -1;
 508 }
 509
 510 /**
 511  * alarm_handle_timer - Callback for posix timers
 512  * @alarm: alarm that fired
 513  *
 514  * Posix timer callback for expired alarm timers.
 515  */
 516 static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
 517                                                         ktime_t now)
 518 {
 519         struct k_itimer *ptr = container_of(alarm, struct k_itimer,
 520                                             it.alarm.alarmtimer);
 521         enum alarmtimer_restart result = ALARMTIMER_NORESTART;
 522         unsigned long flags;
 523         int si_private = 0;
 524
 525         spin_lock_irqsave(&ptr->it_lock, flags);
 526
 527         ptr->it_active = 0;
 528         if (ptr->it_interval)
 529                 si_private = ++ptr->it_requeue_pending;
 530
 531         if (posix_timer_event(ptr, si_private) && ptr->it_interval) {
 532                 /*
 533                  * Handle ignored signals and rearm the timer. This will go
 534                  * away once we handle ignored signals proper.
 535                  */
 536                 ptr->it_overrun += alarm_forward_now(alarm, ptr->it_interval);
 537                 ++ptr->it_requeue_pending;
 538                 ptr->it_active = 1;
 539                 result = ALARMTIMER_RESTART;
 540         }
 541         spin_unlock_irqrestore(&ptr->it_lock, flags);
 542
 543         return result;
 544 }
 545
 546 /**
 547  * alarm_timer_rearm - Posix timer callback for rearming timer
 548  * @timr:       Pointer to the posixtimer data struct
 549  */
 550 static void alarm_timer_rearm(struct k_itimer *timr)
 551 {
 552         struct alarm *alarm = &timr->it.alarm.alarmtimer;
 553
 554         timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
 555         alarm_start(alarm, alarm->node.expires);
 556 }
 557
 558 /**
 559  * alarm_timer_forward - Posix timer callback for forwarding timer
 560  * @timr:       Pointer to the posixtimer data struct
 561  * @now:        Current time to forward the timer against
 562  */
 563 static int alarm_timer_forward(struct k_itimer *timr, ktime_t now)
 564 {
 565         struct alarm *alarm = &timr->it.alarm.alarmtimer;
 566
 567         return (int) alarm_forward(alarm, timr->it_interval, now);
 568 }
 569
 570 /**
 571  * alarm_timer_remaining - Posix timer callback to retrieve remaining time
 572  * @timr:       Pointer to the posixtimer data struct
 573  * @now:        Current time to calculate against
 574  */
 575 static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now)
 576 {
 577         struct alarm *alarm = &timr->it.alarm.alarmtimer;
 578
 579         return ktime_sub(now, alarm->node.expires);
 580 }
 581
 582 /**
 583  * alarm_timer_try_to_cancel - Posix timer callback to cancel a timer
 584  * @timr:       Pointer to the posixtimer data struct
 585  */
 586 static int alarm_timer_try_to_cancel(struct k_itimer *timr)
 587 {
 588         return alarm_try_to_cancel(&timr->it.alarm.alarmtimer);
 589 }
 590
 591 /**
 592  * alarm_timer_arm - Posix timer callback to arm a timer
 593  * @timr:       Pointer to the posixtimer data struct
 594  * @expires:    The new expiry time
 595  * @absolute:   Expiry value is absolute time
 596  * @sigev_none: Posix timer does not deliver signals
 597  */
 598 static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
 599                             bool absolute, bool sigev_none)
 600 {
 601         struct alarm *alarm = &timr->it.alarm.alarmtimer;
 602         struct alarm_base *base = &alarm_bases[alarm->type];
 603
 604         if (!absolute)
 605                 expires = ktime_add_safe(expires, base->gettime());
 606         if (sigev_none)
 607                 alarm->node.expires = expires;
 608         else
 609                 alarm_start(&timr->it.alarm.alarmtimer, expires);
 610 }
 611
 612 /**
 613  * alarm_clock_getres - posix getres interface
 614  * @which_clock: clockid
 615  * @tp: timespec to fill
 616  *
 617  * Returns the granularity of underlying alarm base clock
 618  */
 619 static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
 620 {
 621         if (!alarmtimer_get_rtcdev())
 622                 return -EINVAL;
 623
 624         tp->tv_sec = 0;
 625         tp->tv_nsec = hrtimer_resolution;
 626         return 0;
 627 }
 628
 629 /**
 630  * alarm_clock_get - posix clock_get interface
 631  * @which_clock: clockid
 632  * @tp: timespec to fill.
 633  *
 634  * Provides the underlying alarm base time.
 635  */
 636 static int alarm_clock_get(clockid_t which_clock, struct timespec64 *tp)
 637 {
 638         struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
 639
 640         if (!alarmtimer_get_rtcdev())
 641                 return -EINVAL;
 642
 643         *tp = ktime_to_timespec64(base->gettime());
 644         return 0;
 645 }
 646
 647 /**
 648  * alarm_timer_create - posix timer_create interface
 649  * @new_timer: k_itimer pointer to manage
 650  *
 651  * Initializes the k_itimer structure.
 652  */
 653 static int alarm_timer_create(struct k_itimer *new_timer)
 654 {
 655         enum  alarmtimer_type type;
 656
 657         if (!alarmtimer_get_rtcdev())
 658                 return -ENOTSUPP;
 659
 660         if (!capable(CAP_WAKE_ALARM))
 661                 return -EPERM;
 662
 663         type = clock2alarm(new_timer->it_clock);
 664         alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
 665         return 0;
 666 }
 667
 668 /**
 669  * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
 670  * @alarm: ptr to alarm that fired
 671  *
 672  * Wakes up the task that set the alarmtimer
 673  */
 674 static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
 675                                                                 ktime_t now)
 676 {
 677         struct task_struct *task = (struct task_struct *)alarm->data;
 678
 679         alarm->data = NULL;
 680         if (task)
 681                 wake_up_process(task);
 682         return ALARMTIMER_NORESTART;
 683 }
 684
 685 /**
 686  * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
 687  * @alarm: ptr to alarmtimer
 688  * @absexp: absolute expiration time
 689  *
 690  * Sets the alarm timer and sleeps until it is fired or interrupted.
 691  */
 692 static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
 693                                 enum alarmtimer_type type)
 694 {
 695         struct restart_block *restart;
 696         alarm->data = (void *)current;
 697         do {
 698                 set_current_state(TASK_INTERRUPTIBLE);
 699                 alarm_start(alarm, absexp);
 700                 if (likely(alarm->data))
 701                         schedule();
 702
 703                 alarm_cancel(alarm);
 704         } while (alarm->data && !signal_pending(current));
 705
 706         __set_current_state(TASK_RUNNING);
 707
 708         if (!alarm->data)
 709                 return 0;
 710
 711         if (freezing(current))
 712                 alarmtimer_freezerset(absexp, type);
 713         restart = &current->restart_block;
 714         if (restart->nanosleep.type != TT_NONE) {
 715                 struct timespec64 rmt;
 716                 ktime_t rem;
 717
 718                 rem = ktime_sub(absexp, alarm_bases[type].gettime());
 719
 720                 if (rem <= 0)
 721                         return 0;
 722                 rmt = ktime_to_timespec64(rem);
 723
 724                 return nanosleep_copyout(restart, &rmt);
 725         }
 726         return -ERESTART_RESTARTBLOCK;
 727 }
 728
 729 /**
 730  * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
 731  * @restart: ptr to restart block
 732  *
 733  * Handles restarted clock_nanosleep calls
 734  */
 735 static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
 736 {
 737         enum  alarmtimer_type type = restart->nanosleep.clockid;
 738         ktime_t exp = restart->nanosleep.expires;
 739         struct alarm alarm;
 740
 741         alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
 742
 743         return alarmtimer_do_nsleep(&alarm, exp, type);
 744 }
 745
 746 /**
 747  * alarm_timer_nsleep - alarmtimer nanosleep
 748  * @which_clock: clockid
 749  * @flags: determins abstime or relative
 750  * @tsreq: requested sleep time (abs or rel)
 751  * @rmtp: remaining sleep time saved
 752  *
 753  * Handles clock_nanosleep calls against _ALARM clockids
 754  */
 755 static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
 756                               const struct timespec64 *tsreq)
 757 {
 758         enum  alarmtimer_type type = clock2alarm(which_clock);
 759         struct restart_block *restart = &current->restart_block;
 760         struct alarm alarm;
 761         ktime_t exp;
 762         int ret = 0;
 763
 764         if (!alarmtimer_get_rtcdev())
 765                 return -ENOTSUPP;
 766
 767         if (flags & ~TIMER_ABSTIME)
 768                 return -EINVAL;
 769
 770         if (!capable(CAP_WAKE_ALARM))
 771                 return -EPERM;
 772
 773         alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
 774
 775         exp = timespec64_to_ktime(*tsreq);
 776         /* Convert (if necessary) to absolute time */
 777         if (flags != TIMER_ABSTIME) {
 778                 ktime_t now = alarm_bases[type].gettime();
 779                 exp = ktime_add(now, exp);
 780         }
 781
 782         ret = alarmtimer_do_nsleep(&alarm, exp, type);
 783         if (ret != -ERESTART_RESTARTBLOCK)
 784                 return ret;
 785
 786         /* abs timers don't set remaining time or restart */
 787         if (flags == TIMER_ABSTIME)
 788                 return -ERESTARTNOHAND;
 789
 790         restart->fn = alarm_timer_nsleep_restart;
 791         restart->nanosleep.clockid = type;
 792         restart->nanosleep.expires = exp;
 793         return ret;
 794 }
 795
 796 const struct k_clock alarm_clock = {
 797         .clock_getres           = alarm_clock_getres,
 798         .clock_get              = alarm_clock_get,
 799         .timer_create           = alarm_timer_create,
 800         .timer_set              = common_timer_set,
 801         .timer_del              = common_timer_del,
 802         .timer_get              = common_timer_get,
 803         .timer_arm              = alarm_timer_arm,
 804         .timer_rearm            = alarm_timer_rearm,
 805         .timer_forward          = alarm_timer_forward,
 806         .timer_remaining        = alarm_timer_remaining,
 807         .timer_try_to_cancel    = alarm_timer_try_to_cancel,
 808         .nsleep                 = alarm_timer_nsleep,
 809 };
 810 #endif /* CONFIG_POSIX_TIMERS */
 811
 812
 813 /* Suspend hook structures */
 814 static const struct dev_pm_ops alarmtimer_pm_ops = {
 815         .suspend = alarmtimer_suspend,
 816         .resume = alarmtimer_resume,
 817 };
 818
 819 static struct platform_driver alarmtimer_driver = {
 820         .driver = {
 821                 .name = "alarmtimer",
 822                 .pm = &alarmtimer_pm_ops,
 823         }
 824 };
 825
 826 /**
 827  * alarmtimer_init - Initialize alarm timer code
 828  *
 829  * This function initializes the alarm bases and registers
 830  * the posix clock ids.
 831  */
 832 static int __init alarmtimer_init(void)
 833 {
 834         struct platform_device *pdev;
 835         int error = 0;
 836         int i;
 837
 838         alarmtimer_rtc_timer_init();
 839
 840         /* Initialize alarm bases */
 841         alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
 842         alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
 843         alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
 844         alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
 845         for (i = 0; i < ALARM_NUMTYPE; i++) {
 846                 timerqueue_init_head(&alarm_bases[i].timerqueue);
 847                 spin_lock_init(&alarm_bases[i].lock);
 848         }
 849
 850         error = alarmtimer_rtc_interface_setup();
 851         if (error)
 852                 return error;
 853
 854         error = platform_driver_register(&alarmtimer_driver);
 855         if (error)
 856                 goto out_if;
 857
 858         pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
 859         if (IS_ERR(pdev)) {
 860                 error = PTR_ERR(pdev);
 861                 goto out_drv;
 862         }
 863         ws = wakeup_source_register("alarmtimer");
 864         return 0;
 865
 866 out_drv:
 867         platform_driver_unregister(&alarmtimer_driver);
 868 out_if:
 869         alarmtimer_rtc_interface_remove();
 870         return error;
 871 }
 872 device_initcall(alarmtimer_init);