// SPDX-License-Identifier: GPL-2.0 /* * Alarmtimer interface * * This interface provides a timer which is similar to hrtimers, * but triggers a RTC alarm if the box is suspend. * * This interface is influenced by the Android RTC Alarm timer * interface. * * Copyright (C) 2010 IBM Corporation * * Author: John Stultz */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "posix-timers.h" #define CREATE_TRACE_POINTS #include /** * struct alarm_base - Alarm timer bases * @lock: Lock for syncrhonized access to the base * @timerqueue: Timerqueue head managing the list of events * @get_ktime: Function to read the time correlating to the base * @get_timespec: Function to read the namespace time correlating to the base * @base_clockid: clockid for the base */ static struct alarm_base { spinlock_t lock; struct timerqueue_head timerqueue; ktime_t (*get_ktime)(void); void (*get_timespec)(struct timespec64 *tp); clockid_t base_clockid; } alarm_bases[ALARM_NUMTYPE]; #if defined(CONFIG_POSIX_TIMERS) || defined(CONFIG_RTC_CLASS) /* freezer information to handle clock_nanosleep triggered wakeups */ static enum alarmtimer_type freezer_alarmtype; static ktime_t freezer_expires; static ktime_t freezer_delta; static DEFINE_SPINLOCK(freezer_delta_lock); #endif #ifdef CONFIG_RTC_CLASS /* rtc timer and device for setting alarm wakeups at suspend */ static struct rtc_timer rtctimer; static struct rtc_device *rtcdev; static DEFINE_SPINLOCK(rtcdev_lock); /** * alarmtimer_get_rtcdev - Return selected rtcdevice * * This function returns the rtc device to use for wakealarms. */ struct rtc_device *alarmtimer_get_rtcdev(void) { unsigned long flags; struct rtc_device *ret; spin_lock_irqsave(&rtcdev_lock, flags); ret = rtcdev; spin_unlock_irqrestore(&rtcdev_lock, flags); return ret; } EXPORT_SYMBOL_GPL(alarmtimer_get_rtcdev); static int alarmtimer_rtc_add_device(struct device *dev) { unsigned long flags; struct rtc_device *rtc = to_rtc_device(dev); struct platform_device *pdev; int ret = 0; if (rtcdev) return -EBUSY; if (!test_bit(RTC_FEATURE_ALARM, rtc->features)) return -1; if (!device_may_wakeup(rtc->dev.parent)) return -1; pdev = platform_device_register_data(dev, "alarmtimer", PLATFORM_DEVID_AUTO, NULL, 0); if (!IS_ERR(pdev)) device_init_wakeup(&pdev->dev, true); spin_lock_irqsave(&rtcdev_lock, flags); if (!IS_ERR(pdev) && !rtcdev) { if (!try_module_get(rtc->owner)) { ret = -1; goto unlock; } rtcdev = rtc; /* hold a reference so it doesn't go away */ get_device(dev); pdev = NULL; } else { ret = -1; } unlock: spin_unlock_irqrestore(&rtcdev_lock, flags); platform_device_unregister(pdev); return ret; } static inline void alarmtimer_rtc_timer_init(void) { rtc_timer_init(&rtctimer, NULL, NULL); } static struct class_interface alarmtimer_rtc_interface = { .add_dev = &alarmtimer_rtc_add_device, }; static int alarmtimer_rtc_interface_setup(void) { alarmtimer_rtc_interface.class = &rtc_class; return class_interface_register(&alarmtimer_rtc_interface); } static void alarmtimer_rtc_interface_remove(void) { class_interface_unregister(&alarmtimer_rtc_interface); } #else static inline int alarmtimer_rtc_interface_setup(void) { return 0; } static inline void alarmtimer_rtc_interface_remove(void) { } static inline void alarmtimer_rtc_timer_init(void) { } #endif /** * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue * @base: pointer to the base where the timer is being run * @alarm: pointer to alarm being enqueued. * * Adds alarm to a alarm_base timerqueue * * Must hold base->lock when calling. */ static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm) { if (alarm->state & ALARMTIMER_STATE_ENQUEUED) timerqueue_del(&base->timerqueue, &alarm->node); timerqueue_add(&base->timerqueue, &alarm->node); alarm->state |= ALARMTIMER_STATE_ENQUEUED; } /** * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue * @base: pointer to the base where the timer is running * @alarm: pointer to alarm being removed * * Removes alarm to a alarm_base timerqueue * * Must hold base->lock when calling. */ static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm) { if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED)) return; timerqueue_del(&base->timerqueue, &alarm->node); alarm->state &= ~ALARMTIMER_STATE_ENQUEUED; } /** * alarmtimer_fired - Handles alarm hrtimer being fired. * @timer: pointer to hrtimer being run * * When a alarm timer fires, this runs through the timerqueue to * see which alarms expired, and runs those. If there are more alarm * timers queued for the future, we set the hrtimer to fire when * the next future alarm timer expires. */ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer) { struct alarm *alarm = container_of(timer, struct alarm, timer); struct alarm_base *base = &alarm_bases[alarm->type]; scoped_guard (spinlock_irqsave, &base->lock) alarmtimer_dequeue(base, alarm); if (alarm->function) alarm->function(alarm, base->get_ktime()); trace_alarmtimer_fired(alarm, base->get_ktime()); return HRTIMER_NORESTART; } ktime_t alarm_expires_remaining(const struct alarm *alarm) { struct alarm_base *base = &alarm_bases[alarm->type]; return ktime_sub(alarm->node.expires, base->get_ktime()); } EXPORT_SYMBOL_GPL(alarm_expires_remaining); #ifdef CONFIG_RTC_CLASS /** * alarmtimer_suspend - Suspend time callback * @dev: unused * * When we are going into suspend, we look through the bases * to see which is the soonest timer to expire. We then * set an rtc timer to fire that far into the future, which * will wake us from suspend. */ static int alarmtimer_suspend(struct device *dev) { ktime_t min, now, expires; int i, ret, type; struct rtc_device *rtc; unsigned long flags; struct rtc_time tm; spin_lock_irqsave(&freezer_delta_lock, flags); min = freezer_delta; expires = freezer_expires; type = freezer_alarmtype; freezer_delta = 0; spin_unlock_irqrestore(&freezer_delta_lock, flags); rtc = alarmtimer_get_rtcdev(); /* If we have no rtcdev, just return */ if (!rtc) return 0; /* Find the soonest timer to expire*/ for (i = 0; i < ALARM_NUMTYPE; i++) { struct alarm_base *base = &alarm_bases[i]; struct timerqueue_node *next; ktime_t delta; spin_lock_irqsave(&base->lock, flags); next = timerqueue_getnext(&base->timerqueue); spin_unlock_irqrestore(&base->lock, flags); if (!next) continue; delta = ktime_sub(next->expires, base->get_ktime()); if (!min || (delta < min)) { expires = next->expires; min = delta; type = i; } } if (min == 0) return 0; if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) { pm_wakeup_event(dev, 2 * MSEC_PER_SEC); return -EBUSY; } trace_alarmtimer_suspend(expires, type); /* Setup an rtc timer to fire that far in the future */ rtc_timer_cancel(rtc, &rtctimer); rtc_read_time(rtc, &tm); now = rtc_tm_to_ktime(tm); /* * If the RTC alarm timer only supports a limited time offset, set the * alarm time to the maximum supported value. * The system may wake up earlier (possibly much earlier) than expected * when the alarmtimer runs. This is the best the kernel can do if * the alarmtimer exceeds the time that the rtc device can be programmed * for. */ min = rtc_bound_alarmtime(rtc, min); now = ktime_add(now, min); /* Set alarm, if in the past reject suspend briefly to handle */ ret = rtc_timer_start(rtc, &rtctimer, now, 0); if (ret < 0) pm_wakeup_event(dev, MSEC_PER_SEC); return ret; } static int alarmtimer_resume(struct device *dev) { struct rtc_device *rtc; rtc = alarmtimer_get_rtcdev(); if (rtc) rtc_timer_cancel(rtc, &rtctimer); return 0; } #else static int alarmtimer_suspend(struct device *dev) { return 0; } static int alarmtimer_resume(struct device *dev) { return 0; } #endif static void __alarm_init(struct alarm *alarm, enum alarmtimer_type type, void (*function)(struct alarm *, ktime_t)) { timerqueue_init(&alarm->node); alarm->function = function; alarm->type = type; alarm->state = ALARMTIMER_STATE_INACTIVE; } /** * alarm_init - Initialize an alarm structure * @alarm: ptr to alarm to be initialized * @type: the type of the alarm * @function: callback that is run when the alarm fires */ void alarm_init(struct alarm *alarm, enum alarmtimer_type type, void (*function)(struct alarm *, ktime_t)) { hrtimer_setup(&alarm->timer, alarmtimer_fired, alarm_bases[type].base_clockid, HRTIMER_MODE_ABS); __alarm_init(alarm, type, function); } EXPORT_SYMBOL_GPL(alarm_init); /** * alarm_start - Sets an absolute alarm to fire * @alarm: ptr to alarm to set * @start: time to run the alarm */ void alarm_start(struct alarm *alarm, ktime_t start) { struct alarm_base *base = &alarm_bases[alarm->type]; unsigned long flags; spin_lock_irqsave(&base->lock, flags); alarm->node.expires = start; alarmtimer_enqueue(base, alarm); hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_ABS); spin_unlock_irqrestore(&base->lock, flags); trace_alarmtimer_start(alarm, base->get_ktime()); } EXPORT_SYMBOL_GPL(alarm_start); /** * alarm_start_relative - Sets a relative alarm to fire * @alarm: ptr to alarm to set * @start: time relative to now to run the alarm */ void alarm_start_relative(struct alarm *alarm, ktime_t start) { struct alarm_base *base = &alarm_bases[alarm->type]; start = ktime_add_safe(start, base->get_ktime()); alarm_start(alarm, start); } EXPORT_SYMBOL_GPL(alarm_start_relative); void alarm_restart(struct alarm *alarm) { struct alarm_base *base = &alarm_bases[alarm->type]; unsigned long flags; spin_lock_irqsave(&base->lock, flags); hrtimer_set_expires(&alarm->timer, alarm->node.expires); hrtimer_restart(&alarm->timer); alarmtimer_enqueue(base, alarm); spin_unlock_irqrestore(&base->lock, flags); } EXPORT_SYMBOL_GPL(alarm_restart); /** * alarm_try_to_cancel - Tries to cancel an alarm timer * @alarm: ptr to alarm to be canceled * * Returns 1 if the timer was canceled, 0 if it was not running, * and -1 if the callback was running */ int alarm_try_to_cancel(struct alarm *alarm) { struct alarm_base *base = &alarm_bases[alarm->type]; unsigned long flags; int ret; spin_lock_irqsave(&base->lock, flags); ret = hrtimer_try_to_cancel(&alarm->timer); if (ret >= 0) alarmtimer_dequeue(base, alarm); spin_unlock_irqrestore(&base->lock, flags); trace_alarmtimer_cancel(alarm, base->get_ktime()); return ret; } EXPORT_SYMBOL_GPL(alarm_try_to_cancel); /** * alarm_cancel - Spins trying to cancel an alarm timer until it is done * @alarm: ptr to alarm to be canceled * * Returns 1 if the timer was canceled, 0 if it was not active. */ int alarm_cancel(struct alarm *alarm) { for (;;) { int ret = alarm_try_to_cancel(alarm); if (ret >= 0) return ret; hrtimer_cancel_wait_running(&alarm->timer); } } EXPORT_SYMBOL_GPL(alarm_cancel); u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval) { u64 overrun = 1; ktime_t delta; delta = ktime_sub(now, alarm->node.expires); if (delta < 0) return 0; if (unlikely(delta >= interval)) { s64 incr = ktime_to_ns(interval); overrun = ktime_divns(delta, incr); alarm->node.expires = ktime_add_ns(alarm->node.expires, incr*overrun); if (alarm->node.expires > now) return overrun; /* * This (and the ktime_add() below) is the * correction for exact: */ overrun++; } alarm->node.expires = ktime_add_safe(alarm->node.expires, interval); return overrun; } EXPORT_SYMBOL_GPL(alarm_forward); u64 alarm_forward_now(struct alarm *alarm, ktime_t interval) { struct alarm_base *base = &alarm_bases[alarm->type]; return alarm_forward(alarm, base->get_ktime(), interval); } EXPORT_SYMBOL_GPL(alarm_forward_now); #ifdef CONFIG_POSIX_TIMERS static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type) { struct alarm_base *base; unsigned long flags; ktime_t delta; switch(type) { case ALARM_REALTIME: base = &alarm_bases[ALARM_REALTIME]; type = ALARM_REALTIME_FREEZER; break; case ALARM_BOOTTIME: base = &alarm_bases[ALARM_BOOTTIME]; type = ALARM_BOOTTIME_FREEZER; break; default: WARN_ONCE(1, "Invalid alarm type: %d\n", type); return; } delta = ktime_sub(absexp, base->get_ktime()); spin_lock_irqsave(&freezer_delta_lock, flags); if (!freezer_delta || (delta < freezer_delta)) { freezer_delta = delta; freezer_expires = absexp; freezer_alarmtype = type; } spin_unlock_irqrestore(&freezer_delta_lock, flags); } /** * clock2alarm - helper that converts from clockid to alarmtypes * @clockid: clockid. */ static enum alarmtimer_type clock2alarm(clockid_t clockid) { if (clockid == CLOCK_REALTIME_ALARM) return ALARM_REALTIME; if (clockid == CLOCK_BOOTTIME_ALARM) return ALARM_BOOTTIME; return -1; } /** * alarm_handle_timer - Callback for posix timers * @alarm: alarm that fired * @now: time at the timer expiration * * Posix timer callback for expired alarm timers. * * Return: whether the timer is to be restarted */ static void alarm_handle_timer(struct alarm *alarm, ktime_t now) { struct k_itimer *ptr = container_of(alarm, struct k_itimer, it.alarm.alarmtimer); guard(spinlock_irqsave)(&ptr->it_lock); posix_timer_queue_signal(ptr); } /** * alarm_timer_rearm - Posix timer callback for rearming timer * @timr: Pointer to the posixtimer data struct */ static void alarm_timer_rearm(struct k_itimer *timr) { struct alarm *alarm = &timr->it.alarm.alarmtimer; timr->it_overrun += alarm_forward_now(alarm, timr->it_interval); alarm_start(alarm, alarm->node.expires); } /** * alarm_timer_forward - Posix timer callback for forwarding timer * @timr: Pointer to the posixtimer data struct * @now: Current time to forward the timer against */ static s64 alarm_timer_forward(struct k_itimer *timr, ktime_t now) { struct alarm *alarm = &timr->it.alarm.alarmtimer; return alarm_forward(alarm, timr->it_interval, now); } /** * alarm_timer_remaining - Posix timer callback to retrieve remaining time * @timr: Pointer to the posixtimer data struct * @now: Current time to calculate against */ static ktime_t alarm_timer_remaining(struct k_itimer *timr, ktime_t now) { struct alarm *alarm = &timr->it.alarm.alarmtimer; return ktime_sub(alarm->node.expires, now); } /** * alarm_timer_try_to_cancel - Posix timer callback to cancel a timer * @timr: Pointer to the posixtimer data struct */ static int alarm_timer_try_to_cancel(struct k_itimer *timr) { return alarm_try_to_cancel(&timr->it.alarm.alarmtimer); } /** * alarm_timer_wait_running - Posix timer callback to wait for a timer * @timr: Pointer to the posixtimer data struct * * Called from the core code when timer cancel detected that the callback * is running. @timr is unlocked and rcu read lock is held to prevent it * from being freed. */ static void alarm_timer_wait_running(struct k_itimer *timr) { hrtimer_cancel_wait_running(&timr->it.alarm.alarmtimer.timer); } /** * alarm_timer_arm - Posix timer callback to arm a timer * @timr: Pointer to the posixtimer data struct * @expires: The new expiry time * @absolute: Expiry value is absolute time * @sigev_none: Posix timer does not deliver signals */ static void alarm_timer_arm(struct k_itimer *timr, ktime_t expires, bool absolute, bool sigev_none) { struct alarm *alarm = &timr->it.alarm.alarmtimer; struct alarm_base *base = &alarm_bases[alarm->type]; if (!absolute) expires = ktime_add_safe(expires, base->get_ktime()); if (sigev_none) alarm->node.expires = expires; else alarm_start(&timr->it.alarm.alarmtimer, expires); } /** * alarm_clock_getres - posix getres interface * @which_clock: clockid * @tp: timespec to fill * * Returns the granularity of underlying alarm base clock */ static int alarm_clock_getres(const clockid_t which_clock, struct timespec64 *tp) { if (!alarmtimer_get_rtcdev()) return -EINVAL; tp->tv_sec = 0; tp->tv_nsec = hrtimer_resolution; return 0; } /** * alarm_clock_get_timespec - posix clock_get_timespec interface * @which_clock: clockid * @tp: timespec to fill. * * Provides the underlying alarm base time in a tasks time namespace. */ static int alarm_clock_get_timespec(clockid_t which_clock, struct timespec64 *tp) { struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)]; if (!alarmtimer_get_rtcdev()) return -EINVAL; base->get_timespec(tp); return 0; } /** * alarm_clock_get_ktime - posix clock_get_ktime interface * @which_clock: clockid * * Provides the underlying alarm base time in the root namespace. */ static ktime_t alarm_clock_get_ktime(clockid_t which_clock) { struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)]; if (!alarmtimer_get_rtcdev()) return -EINVAL; return base->get_ktime(); } /** * alarm_timer_create - posix timer_create interface * @new_timer: k_itimer pointer to manage * * Initializes the k_itimer structure. */ static int alarm_timer_create(struct k_itimer *new_timer) { enum alarmtimer_type type; if (!alarmtimer_get_rtcdev()) return -EOPNOTSUPP; if (!capable(CAP_WAKE_ALARM)) return -EPERM; type = clock2alarm(new_timer->it_clock); alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer); return 0; } /** * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep * @alarm: ptr to alarm that fired * @now: time at the timer expiration * * Wakes up the task that set the alarmtimer */ static void alarmtimer_nsleep_wakeup(struct alarm *alarm, ktime_t now) { struct task_struct *task = alarm->data; alarm->data = NULL; if (task) wake_up_process(task); } /** * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation * @alarm: ptr to alarmtimer * @absexp: absolute expiration time * @type: alarm type (BOOTTIME/REALTIME). * * Sets the alarm timer and sleeps until it is fired or interrupted. */ static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp, enum alarmtimer_type type) { struct restart_block *restart; alarm->data = (void *)current; do { set_current_state(TASK_INTERRUPTIBLE); alarm_start(alarm, absexp); if (likely(alarm->data)) schedule(); alarm_cancel(alarm); } while (alarm->data && !signal_pending(current)); __set_current_state(TASK_RUNNING); destroy_hrtimer_on_stack(&alarm->timer); if (!alarm->data) return 0; if (freezing(current)) alarmtimer_freezerset(absexp, type); restart = ¤t->restart_block; if (restart->nanosleep.type != TT_NONE) { struct timespec64 rmt; ktime_t rem; rem = ktime_sub(absexp, alarm_bases[type].get_ktime()); if (rem <= 0) return 0; rmt = ktime_to_timespec64(rem); return nanosleep_copyout(restart, &rmt); } return -ERESTART_RESTARTBLOCK; } static void alarm_init_on_stack(struct alarm *alarm, enum alarmtimer_type type, void (*function)(struct alarm *, ktime_t)) { hrtimer_setup_on_stack(&alarm->timer, alarmtimer_fired, alarm_bases[type].base_clockid, HRTIMER_MODE_ABS); __alarm_init(alarm, type, function); } /** * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep * @restart: ptr to restart block * * Handles restarted clock_nanosleep calls */ static long __sched alarm_timer_nsleep_restart(struct restart_block *restart) { enum alarmtimer_type type = restart->nanosleep.clockid; ktime_t exp = restart->nanosleep.expires; struct alarm alarm; alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup); return alarmtimer_do_nsleep(&alarm, exp, type); } /** * alarm_timer_nsleep - alarmtimer nanosleep * @which_clock: clockid * @flags: determines abstime or relative * @tsreq: requested sleep time (abs or rel) * * Handles clock_nanosleep calls against _ALARM clockids */ static int alarm_timer_nsleep(const clockid_t which_clock, int flags, const struct timespec64 *tsreq) { enum alarmtimer_type type = clock2alarm(which_clock); struct restart_block *restart = ¤t->restart_block; struct alarm alarm; ktime_t exp; int ret; if (!alarmtimer_get_rtcdev()) return -EOPNOTSUPP; if (flags & ~TIMER_ABSTIME) return -EINVAL; if (!capable(CAP_WAKE_ALARM)) return -EPERM; alarm_init_on_stack(&alarm, type, alarmtimer_nsleep_wakeup); exp = timespec64_to_ktime(*tsreq); /* Convert (if necessary) to absolute time */ if (flags != TIMER_ABSTIME) { ktime_t now = alarm_bases[type].get_ktime(); exp = ktime_add_safe(now, exp); } else { exp = timens_ktime_to_host(which_clock, exp); } ret = alarmtimer_do_nsleep(&alarm, exp, type); if (ret != -ERESTART_RESTARTBLOCK) return ret; /* abs timers don't set remaining time or restart */ if (flags == TIMER_ABSTIME) return -ERESTARTNOHAND; restart->nanosleep.clockid = type; restart->nanosleep.expires = exp; set_restart_fn(restart, alarm_timer_nsleep_restart); return ret; } const struct k_clock alarm_clock = { .clock_getres = alarm_clock_getres, .clock_get_ktime = alarm_clock_get_ktime, .clock_get_timespec = alarm_clock_get_timespec, .timer_create = alarm_timer_create, .timer_set = common_timer_set, .timer_del = common_timer_del, .timer_get = common_timer_get, .timer_arm = alarm_timer_arm, .timer_rearm = alarm_timer_rearm, .timer_forward = alarm_timer_forward, .timer_remaining = alarm_timer_remaining, .timer_try_to_cancel = alarm_timer_try_to_cancel, .timer_wait_running = alarm_timer_wait_running, .nsleep = alarm_timer_nsleep, }; #endif /* CONFIG_POSIX_TIMERS */ /* Suspend hook structures */ static const struct dev_pm_ops alarmtimer_pm_ops = { .suspend = alarmtimer_suspend, .resume = alarmtimer_resume, }; static struct platform_driver alarmtimer_driver = { .driver = { .name = "alarmtimer", .pm = &alarmtimer_pm_ops, } }; static void get_boottime_timespec(struct timespec64 *tp) { ktime_get_boottime_ts64(tp); timens_add_boottime(tp); } /** * alarmtimer_init - Initialize alarm timer code * * This function initializes the alarm bases and registers * the posix clock ids. */ static int __init alarmtimer_init(void) { int error; int i; alarmtimer_rtc_timer_init(); /* Initialize alarm bases */ alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME; alarm_bases[ALARM_REALTIME].get_ktime = &ktime_get_real; alarm_bases[ALARM_REALTIME].get_timespec = ktime_get_real_ts64; alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME; alarm_bases[ALARM_BOOTTIME].get_ktime = &ktime_get_boottime; alarm_bases[ALARM_BOOTTIME].get_timespec = get_boottime_timespec; for (i = 0; i < ALARM_NUMTYPE; i++) { timerqueue_init_head(&alarm_bases[i].timerqueue); spin_lock_init(&alarm_bases[i].lock); } error = alarmtimer_rtc_interface_setup(); if (error) return error; error = platform_driver_register(&alarmtimer_driver); if (error) goto out_if; return 0; out_if: alarmtimer_rtc_interface_remove(); return error; } device_initcall(alarmtimer_init);