/* * Alarmtimer interface * * This interface provides a timer which is similarto 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 Corperation * * Author: John Stultz * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include static struct alarm_base { spinlock_t lock; struct timerqueue_head timerqueue; struct hrtimer timer; ktime_t (*gettime)(void); clockid_t base_clockid; struct work_struct irqwork; } alarm_bases[ALARM_NUMTYPE]; static struct rtc_timer rtctimer; static struct rtc_device *rtcdev; static ktime_t freezer_delta; static DEFINE_SPINLOCK(freezer_delta_lock); /************************************************************************** * alarmtimer management code */ /* * 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 and if necessary sets * an hrtimer to run. * * Must hold base->lock when calling. */ static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm) { timerqueue_add(&base->timerqueue, &alarm->node); if (&alarm->node == timerqueue_getnext(&base->timerqueue)) { hrtimer_try_to_cancel(&base->timer); hrtimer_start(&base->timer, alarm->node.expires, HRTIMER_MODE_ABS); } } /* * alarmtimer_remove - 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 and if necessary sets * a new timer to run. * * Must hold base->lock when calling. */ static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm) { struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue); timerqueue_del(&base->timerqueue, &alarm->node); if (next == &alarm->node) { hrtimer_try_to_cancel(&base->timer); next = timerqueue_getnext(&base->timerqueue); if (!next) return; hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS); } } /* * alarmtimer_do_work - Handles alarm being fired. * @work: pointer to workqueue being run * * When a timer fires, this runs through the timerqueue to see * which alarm timers, and run those that expired. If there are * more alarm timers queued, we set the hrtimer to fire in the * future. */ void alarmtimer_do_work(struct work_struct *work) { struct alarm_base *base = container_of(work, struct alarm_base, irqwork); struct timerqueue_node *next; unsigned long flags; ktime_t now; spin_lock_irqsave(&base->lock, flags); now = base->gettime(); while ((next = timerqueue_getnext(&base->timerqueue))) { struct alarm *alarm; ktime_t expired = next->expires; if (expired.tv64 >= now.tv64) break; alarm = container_of(next, struct alarm, node); timerqueue_del(&base->timerqueue, &alarm->node); alarm->enabled = 0; /* Re-add periodic timers */ if (alarm->period.tv64) { alarm->node.expires = ktime_add(expired, alarm->period); timerqueue_add(&base->timerqueue, &alarm->node); alarm->enabled = 1; } spin_unlock_irqrestore(&base->lock, flags); if (alarm->function) alarm->function(alarm); spin_lock_irqsave(&base->lock, flags); } if (next) { hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS); } spin_unlock_irqrestore(&base->lock, flags); } /* * alarmtimer_fired - Handles alarm hrtimer being fired. * @timer: pointer to hrtimer being run * * When a timer fires, this schedules the do_work function to * be run. */ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer) { struct alarm_base *base = container_of(timer, struct alarm_base, timer); schedule_work(&base->irqwork); return HRTIMER_NORESTART; } /* * alarmtimer_suspend - Suspend time callback * @dev: unused * @state: 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) { struct rtc_time tm; ktime_t min, now; unsigned long flags; int i; spin_lock_irqsave(&freezer_delta_lock, flags); min = freezer_delta; freezer_delta = ktime_set(0, 0); spin_unlock_irqrestore(&freezer_delta_lock, flags); /* If we have no rtcdev, just return */ if (!rtcdev) 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->gettime()); if (!min.tv64 || (delta.tv64 < min.tv64)) min = delta; } if (min.tv64 == 0) return 0; /* XXX - Should we enforce a minimum sleep time? */ WARN_ON(min.tv64 < NSEC_PER_SEC); /* Setup an rtc timer to fire that far in the future */ rtc_timer_cancel(rtcdev, &rtctimer); rtc_read_time(rtcdev, &tm); now = rtc_tm_to_ktime(tm); now = ktime_add(now, min); rtc_timer_start(rtcdev, &rtctimer, now, ktime_set(0, 0)); return 0; } /************************************************************************** * alarm kernel interface code */ /* * 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 * * In-kernel interface to initializes the alarm structure. */ void alarm_init(struct alarm *alarm, enum alarmtimer_type type, void (*function)(struct alarm *)) { timerqueue_init(&alarm->node); alarm->period = ktime_set(0, 0); alarm->function = function; alarm->type = type; alarm->enabled = 0; } /* * alarm_start - Sets an alarm to fire * @alarm: ptr to alarm to set * @start: time to run the alarm * @period: period at which the alarm will recur * * In-kernel interface set an alarm timer. */ void alarm_start(struct alarm *alarm, ktime_t start, ktime_t period) { struct alarm_base *base = &alarm_bases[alarm->type]; unsigned long flags; spin_lock_irqsave(&base->lock, flags); if (alarm->enabled) alarmtimer_remove(base, alarm); alarm->node.expires = start; alarm->period = period; alarmtimer_enqueue(base, alarm); alarm->enabled = 1; spin_unlock_irqrestore(&base->lock, flags); } /* * alarm_cancel - Tries to cancel an alarm timer * @alarm: ptr to alarm to be canceled * * In-kernel interface to cancel an alarm timer. */ void alarm_cancel(struct alarm *alarm) { struct alarm_base *base = &alarm_bases[alarm->type]; unsigned long flags; spin_lock_irqsave(&base->lock, flags); if (alarm->enabled) alarmtimer_remove(base, alarm); alarm->enabled = 0; spin_unlock_irqrestore(&base->lock, flags); } /************************************************************************** * alarmtimer initialization code */ /* Suspend hook structures */ static const struct dev_pm_ops alarmtimer_pm_ops = { .suspend = alarmtimer_suspend, }; static struct platform_driver alarmtimer_driver = { .driver = { .name = "alarmtimer", .pm = &alarmtimer_pm_ops, } }; /** * 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 = 0; int i; /* Initialize alarm bases */ alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME; alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real; alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME; alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime; for (i = 0; i < ALARM_NUMTYPE; i++) { timerqueue_init_head(&alarm_bases[i].timerqueue); spin_lock_init(&alarm_bases[i].lock); hrtimer_init(&alarm_bases[i].timer, alarm_bases[i].base_clockid, HRTIMER_MODE_ABS); alarm_bases[i].timer.function = alarmtimer_fired; INIT_WORK(&alarm_bases[i].irqwork, alarmtimer_do_work); } error = platform_driver_register(&alarmtimer_driver); platform_device_register_simple("alarmtimer", -1, NULL, 0); return error; } device_initcall(alarmtimer_init); /** * has_wakealarm - check rtc device has wakealarm ability * @dev: current device * @name_ptr: name to be returned * * This helper function checks to see if the rtc device can wake * from suspend. */ static int __init has_wakealarm(struct device *dev, void *name_ptr) { struct rtc_device *candidate = to_rtc_device(dev); if (!candidate->ops->set_alarm) return 0; if (!device_may_wakeup(candidate->dev.parent)) return 0; *(const char **)name_ptr = dev_name(dev); return 1; } /** * alarmtimer_init_late - Late initializing of alarmtimer code * * This function locates a rtc device to use for wakealarms. * Run as late_initcall to make sure rtc devices have been * registered. */ static int __init alarmtimer_init_late(void) { char *str; /* Find an rtc device and init the rtc_timer */ class_find_device(rtc_class, NULL, &str, has_wakealarm); if (str) rtcdev = rtc_class_open(str); if (!rtcdev) { printk(KERN_WARNING "No RTC device found, ALARM timers will" " not wake from suspend"); } rtc_timer_init(&rtctimer, NULL, NULL); return 0; } late_initcall(alarmtimer_init_late);