| 1 | |
| 2 | * Alarmtimer interface
|
| 3 | *
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| 4 | * This interface provides a timer which is similarto hrtimers,
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| 5 | * but triggers a RTC alarm if the box is suspend.
|
| 6 | *
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| 7 | * This interface is influenced by the Android RTC Alarm timer
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| 8 | * interface.
|
| 9 | *
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| 10 | * Copyright (C) 2010 IBM Corperation
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| 11 | *
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| 12 | * Author: John Stultz <[email protected]>
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| 13 | *
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| 14 | * This program is free software; you can redistribute it and/or modify
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| 15 | * it under the terms of the GNU General Public License version 2 as
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| 16 | * published by the Free Software Foundation.
|
| 17 |
|
| 18 | #include <linux/time.h>
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| 19 | #include <linux/hrtimer.h>
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| 20 | #include <linux/timerqueue.h>
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| 21 | #include <linux/rtc.h>
|
| 22 | #include <linux/alarmtimer.h>
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| 23 | #include <linux/mutex.h>
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| 24 | #include <linux/platform_device.h>
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| 25 | #include <linux/posix-timers.h>
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| 26 | #include <linux/workqueue.h>
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| 27 | #include <linux/freezer.h>
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| 28 |
|
| 29 | |
| 30 | * struct alarm_base - Alarm timer bases
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| 31 | * @lock: Lock for syncrhonized access to the base
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| 32 | * @timerqueue: Timerqueue head managing the list of events
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| 33 | * @timer: hrtimer used to schedule events while running
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| 34 | * @gettime: Function to read the time correlating to the base
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| 35 | * @base_clockid: clockid for the base
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| 36 |
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| 37 | static struct alarm_base {
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| 38 | spinlock_t lock;
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| 39 | struct timerqueue_head timerqueue;
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| 40 | struct hrtimer timer;
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| 41 | ktime_t (*gettime)(void);
|
| 42 | clockid_t base_clockid;
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| 43 | } alarm_bases[ALARM_NUMTYPE];
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| 44 |
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| 45 |
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| 46 | static ktime_t freezer_delta;
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| 47 | static DEFINE_SPINLOCK(freezer_delta_lock);
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| 48 |
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| 49 | #ifdef CONFIG_RTC_CLASS
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| 50 |
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| 51 | static struct rtc_timer rtctimer;
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| 52 | static struct rtc_device *rtcdev;
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| 53 | static DEFINE_SPINLOCK(rtcdev_lock);
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| 54 |
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| 55 | |
| 56 | * alarmtimer_get_rtcdev - Return selected rtcdevice
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| 57 | *
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| 58 | * This function returns the rtc device to use for wakealarms.
|
| 59 | * If one has not already been chosen, it checks to see if a
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| 60 | * functional rtc device is available.
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| 61 |
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| 62 | struct rtc_device *alarmtimer_get_rtcdev(void)
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| 63 | {
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| 64 | unsigned long flags;
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| 65 | struct rtc_device *ret;
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| 66 |
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| 67 | spin_lock_irqsave(&rtcdev_lock, flags);
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| 68 | ret = rtcdev;
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| 69 | spin_unlock_irqrestore(&rtcdev_lock, flags);
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| 70 |
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| 71 | return ret;
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| 72 | }
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| 73 |
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| 74 |
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| 75 | static int alarmtimer_rtc_add_device(struct device *dev,
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| 76 | struct class_interface *class_intf)
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| 77 | {
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| 78 | unsigned long flags;
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| 79 | struct rtc_device *rtc = to_rtc_device(dev);
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| 80 |
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| 81 | if (rtcdev)
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| 82 | return -EBUSY;
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| 83 |
|
| 84 | if (!rtc->ops->set_alarm)
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| 85 | return -1;
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| 86 | if (!device_may_wakeup(rtc->dev.parent))
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| 87 | return -1;
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| 88 |
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| 89 | spin_lock_irqsave(&rtcdev_lock, flags);
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| 90 | if (!rtcdev) {
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| 91 | rtcdev = rtc;
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| 92 |
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| 93 | get_device(dev);
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| 94 | }
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| 95 | spin_unlock_irqrestore(&rtcdev_lock, flags);
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| 96 | return 0;
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| 97 | }
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| 98 |
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| 99 | static inline void alarmtimer_rtc_timer_init(void)
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| 100 | {
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| 101 | rtc_timer_init(&rtctimer, NULL, NULL);
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| 102 | }
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| 103 |
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| 104 | static struct class_interface alarmtimer_rtc_interface = {
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| 105 | .add_dev = &alarmtimer_rtc_add_device,
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| 106 | };
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| 107 |
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| 108 | static int alarmtimer_rtc_interface_setup(void)
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| 109 | {
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| 110 | alarmtimer_rtc_interface.class = rtc_class;
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| 111 | return class_interface_register(&alarmtimer_rtc_interface);
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| 112 | }
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| 113 | static void alarmtimer_rtc_interface_remove(void)
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| 114 | {
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| 115 | class_interface_unregister(&alarmtimer_rtc_interface);
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| 116 | }
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| 117 | #else
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| 118 | struct rtc_device *alarmtimer_get_rtcdev(void)
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| 119 | {
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| 120 | return NULL;
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| 121 | }
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| 122 | #define rtcdev (NULL)
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| 123 | static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
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| 124 | static inline void alarmtimer_rtc_interface_remove(void) { }
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| 125 | static inline void alarmtimer_rtc_timer_init(void) { }
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| 126 | #endif
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| 127 |
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| 128 | |
| 129 | * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
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| 130 | * @base: pointer to the base where the timer is being run
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| 131 | * @alarm: pointer to alarm being enqueued.
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| 132 | *
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| 133 | * Adds alarm to a alarm_base timerqueue and if necessary sets
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| 134 | * an hrtimer to run.
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| 135 | *
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| 136 | * Must hold base->lock when calling.
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| 137 |
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| 138 | static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm)
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| 139 | {
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| 140 | timerqueue_add(&base->timerqueue, &alarm->node);
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| 141 | alarm->state |= ALARMTIMER_STATE_ENQUEUED;
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| 142 |
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| 143 | if (&alarm->node == timerqueue_getnext(&base->timerqueue)) {
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| 144 | hrtimer_try_to_cancel(&base->timer);
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| 145 | hrtimer_start(&base->timer, alarm->node.expires,
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| 146 | HRTIMER_MODE_ABS);
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| 147 | }
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| 148 | }
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| 149 |
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| 150 | |
| 151 | * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue
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| 152 | * @base: pointer to the base where the timer is running
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| 153 | * @alarm: pointer to alarm being removed
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| 154 | *
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| 155 | * Removes alarm to a alarm_base timerqueue and if necessary sets
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| 156 | * a new timer to run.
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| 157 | *
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| 158 | * Must hold base->lock when calling.
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| 159 |
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| 160 | static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm)
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| 161 | {
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| 162 | struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue);
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| 163 |
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| 164 | if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED))
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| 165 | return;
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| 166 |
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| 167 | timerqueue_del(&base->timerqueue, &alarm->node);
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| 168 | alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
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| 169 |
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| 170 | if (next == &alarm->node) {
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| 171 | hrtimer_try_to_cancel(&base->timer);
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| 172 | next = timerqueue_getnext(&base->timerqueue);
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| 173 | if (!next)
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| 174 | return;
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| 175 | hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS);
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| 176 | }
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| 177 | }
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| 178 |
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| 179 |
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| 180 | |
| 181 | * alarmtimer_fired - Handles alarm hrtimer being fired.
|
| 182 | * @timer: pointer to hrtimer being run
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| 183 | *
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| 184 | * When a alarm timer fires, this runs through the timerqueue to
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| 185 | * see which alarms expired, and runs those. If there are more alarm
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| 186 | * timers queued for the future, we set the hrtimer to fire when
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| 187 | * when the next future alarm timer expires.
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| 188 |
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| 189 | static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
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| 190 | {
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| 191 | struct alarm_base *base = container_of(timer, struct alarm_base, timer);
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| 192 | struct timerqueue_node *next;
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| 193 | unsigned long flags;
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| 194 | ktime_t now;
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| 195 | int ret = HRTIMER_NORESTART;
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| 196 | int restart = ALARMTIMER_NORESTART;
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| 197 |
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| 198 | spin_lock_irqsave(&base->lock, flags);
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| 199 | now = base->gettime();
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| 200 | while ((next = timerqueue_getnext(&base->timerqueue))) {
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| 201 | struct alarm *alarm;
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| 202 | ktime_t expired = next->expires;
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| 203 |
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| 204 | if (expired.tv64 > now.tv64)
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| 205 | break;
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| 206 |
|
| 207 | alarm = container_of(next, struct alarm, node);
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| 208 |
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| 209 | timerqueue_del(&base->timerqueue, &alarm->node);
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| 210 | alarm->state &= ~ALARMTIMER_STATE_ENQUEUED;
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| 211 |
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| 212 | alarm->state |= ALARMTIMER_STATE_CALLBACK;
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| 213 | spin_unlock_irqrestore(&base->lock, flags);
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| 214 | if (alarm->function)
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| 215 | restart = alarm->function(alarm, now);
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| 216 | spin_lock_irqsave(&base->lock, flags);
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| 217 | alarm->state &= ~ALARMTIMER_STATE_CALLBACK;
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| 218 |
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| 219 | if (restart != ALARMTIMER_NORESTART) {
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| 220 | timerqueue_add(&base->timerqueue, &alarm->node);
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| 221 | alarm->state |= ALARMTIMER_STATE_ENQUEUED;
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| 222 | }
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| 223 | }
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| 224 |
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| 225 | if (next) {
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| 226 | hrtimer_set_expires(&base->timer, next->expires);
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| 227 | ret = HRTIMER_RESTART;
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| 228 | }
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| 229 | spin_unlock_irqrestore(&base->lock, flags);
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| 230 |
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| 231 | return ret;
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| 232 |
|
| 233 | }
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| 234 |
|
| 235 | #ifdef CONFIG_RTC_CLASS
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| 236 | |
| 237 | * alarmtimer_suspend - Suspend time callback
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| 238 | * @dev: unused
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| 239 | * @state: unused
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| 240 | *
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| 241 | * When we are going into suspend, we look through the bases
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| 242 | * to see which is the soonest timer to expire. We then
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| 243 | * set an rtc timer to fire that far into the future, which
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| 244 | * will wake us from suspend.
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| 245 |
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| 246 | static int alarmtimer_suspend(struct device *dev)
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| 247 | {
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| 248 | struct rtc_time tm;
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| 249 | ktime_t min, now;
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| 250 | unsigned long flags;
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| 251 | struct rtc_device *rtc;
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| 252 | int i;
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| 253 |
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| 254 | spin_lock_irqsave(&freezer_delta_lock, flags);
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| 255 | min = freezer_delta;
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| 256 | freezer_delta = ktime_set(0, 0);
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| 257 | spin_unlock_irqrestore(&freezer_delta_lock, flags);
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| 258 |
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| 259 | rtc = alarmtimer_get_rtcdev();
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| 260 |
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| 261 | if (!rtc)
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| 262 | return 0;
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| 263 |
|
| 264 |
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| 265 | for (i = 0; i < ALARM_NUMTYPE; i++) {
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| 266 | struct alarm_base *base = &alarm_bases[i];
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| 267 | struct timerqueue_node *next;
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| 268 | ktime_t delta;
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| 269 |
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| 270 | spin_lock_irqsave(&base->lock, flags);
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| 271 | next = timerqueue_getnext(&base->timerqueue);
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| 272 | spin_unlock_irqrestore(&base->lock, flags);
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| 273 | if (!next)
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| 274 | continue;
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| 275 | delta = ktime_sub(next->expires, base->gettime());
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| 276 | if (!min.tv64 || (delta.tv64 < min.tv64))
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| 277 | min = delta;
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| 278 | }
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| 279 | if (min.tv64 == 0)
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| 280 | return 0;
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| 281 |
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| 282 |
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| 283 | WARN_ON(min.tv64 < NSEC_PER_SEC);
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| 284 |
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| 285 |
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| 286 | rtc_timer_cancel(rtc, &rtctimer);
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| 287 | rtc_read_time(rtc, &tm);
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| 288 | now = rtc_tm_to_ktime(tm);
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| 289 | now = ktime_add(now, min);
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| 290 |
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| 291 | rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
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| 292 |
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| 293 | return 0;
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| 294 | }
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| 295 | #else
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| 296 | static int alarmtimer_suspend(struct device *dev)
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| 297 | {
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| 298 | return 0;
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| 299 | }
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| 300 | #endif
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| 301 |
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| 302 | static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type)
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| 303 | {
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| 304 | ktime_t delta;
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| 305 | unsigned long flags;
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| 306 | struct alarm_base *base = &alarm_bases[type];
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| 307 |
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| 308 | delta = ktime_sub(absexp, base->gettime());
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| 309 |
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| 310 | spin_lock_irqsave(&freezer_delta_lock, flags);
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| 311 | if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64))
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| 312 | freezer_delta = delta;
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| 313 | spin_unlock_irqrestore(&freezer_delta_lock, flags);
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| 314 | }
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| 315 |
|
| 316 |
|
| 317 | |
| 318 | * alarm_init - Initialize an alarm structure
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| 319 | * @alarm: ptr to alarm to be initialized
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| 320 | * @type: the type of the alarm
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| 321 | * @function: callback that is run when the alarm fires
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| 322 |
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| 323 | void alarm_init(struct alarm *alarm, enum alarmtimer_type type,
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| 324 | enum alarmtimer_restart (*function)(struct alarm *, ktime_t))
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| 325 | {
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| 326 | timerqueue_init(&alarm->node);
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| 327 | alarm->function = function;
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| 328 | alarm->type = type;
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| 329 | alarm->state = ALARMTIMER_STATE_INACTIVE;
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| 330 | }
|
| 331 |
|
| 332 | |
| 333 | * alarm_start - Sets an alarm to fire
|
| 334 | * @alarm: ptr to alarm to set
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| 335 | * @start: time to run the alarm
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| 336 |
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| 337 | void alarm_start(struct alarm *alarm, ktime_t start)
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| 338 | {
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| 339 | struct alarm_base *base = &alarm_bases[alarm->type];
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| 340 | unsigned long flags;
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| 341 |
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| 342 | spin_lock_irqsave(&base->lock, flags);
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| 343 | if (alarmtimer_active(alarm))
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| 344 | alarmtimer_remove(base, alarm);
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| 345 | alarm->node.expires = start;
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| 346 | alarmtimer_enqueue(base, alarm);
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| 347 | spin_unlock_irqrestore(&base->lock, flags);
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| 348 | }
|
| 349 |
|
| 350 | |
| 351 | * alarm_try_to_cancel - Tries to cancel an alarm timer
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| 352 | * @alarm: ptr to alarm to be canceled
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| 353 | *
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| 354 | * Returns 1 if the timer was canceled, 0 if it was not running,
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| 355 | * and -1 if the callback was running
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| 356 |
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| 357 | int alarm_try_to_cancel(struct alarm *alarm)
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| 358 | {
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| 359 | struct alarm_base *base = &alarm_bases[alarm->type];
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| 360 | unsigned long flags;
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| 361 | int ret = -1;
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| 362 | spin_lock_irqsave(&base->lock, flags);
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| 363 |
|
| 364 | if (alarmtimer_callback_running(alarm))
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| 365 | goto out;
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| 366 |
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| 367 | if (alarmtimer_is_queued(alarm)) {
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| 368 | alarmtimer_remove(base, alarm);
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| 369 | ret = 1;
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| 370 | } else
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| 371 | ret = 0;
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| 372 | out:
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| 373 | spin_unlock_irqrestore(&base->lock, flags);
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| 374 | return ret;
|
| 375 | }
|
| 376 |
|
| 377 |
|
| 378 | |
| 379 | * alarm_cancel - Spins trying to cancel an alarm timer until it is done
|
| 380 | * @alarm: ptr to alarm to be canceled
|
| 381 | *
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| 382 | * Returns 1 if the timer was canceled, 0 if it was not active.
|
| 383 |
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| 384 | int alarm_cancel(struct alarm *alarm)
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| 385 | {
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| 386 | for (;;) {
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| 387 | int ret = alarm_try_to_cancel(alarm);
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| 388 | if (ret >= 0)
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| 389 | return ret;
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| 390 | cpu_relax();
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| 391 | }
|
| 392 | }
|
| 393 |
|
| 394 |
|
| 395 | u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
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| 396 | {
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| 397 | u64 overrun = 1;
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| 398 | ktime_t delta;
|
| 399 |
|
| 400 | delta = ktime_sub(now, alarm->node.expires);
|
| 401 |
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| 402 | if (delta.tv64 < 0)
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| 403 | return 0;
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| 404 |
|
| 405 | if (unlikely(delta.tv64 >= interval.tv64)) {
|
| 406 | s64 incr = ktime_to_ns(interval);
|
| 407 |
|
| 408 | overrun = ktime_divns(delta, incr);
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| 409 |
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| 410 | alarm->node.expires = ktime_add_ns(alarm->node.expires,
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| 411 | incr*overrun);
|
| 412 |
|
| 413 | if (alarm->node.expires.tv64 > now.tv64)
|
| 414 | return overrun;
|
| 415 | |
| 416 | * This (and the ktime_add() below) is the
|
| 417 | * correction for exact:
|
| 418 |
|
| 419 | overrun++;
|
| 420 | }
|
| 421 |
|
| 422 | alarm->node.expires = ktime_add(alarm->node.expires, interval);
|
| 423 | return overrun;
|
| 424 | }
|
| 425 |
|
| 426 |
|
| 427 |
|
| 428 |
|
| 429 | |
| 430 | * clock2alarm - helper that converts from clockid to alarmtypes
|
| 431 | * @clockid: clockid.
|
| 432 |
|
| 433 | static enum alarmtimer_type clock2alarm(clockid_t clockid)
|
| 434 | {
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| 435 | if (clockid == CLOCK_REALTIME_ALARM)
|
| 436 | return ALARM_REALTIME;
|
| 437 | if (clockid == CLOCK_BOOTTIME_ALARM)
|
| 438 | return ALARM_BOOTTIME;
|
| 439 | return -1;
|
| 440 | }
|
| 441 |
|
| 442 | |
| 443 | * alarm_handle_timer - Callback for posix timers
|
| 444 | * @alarm: alarm that fired
|
| 445 | *
|
| 446 | * Posix timer callback for expired alarm timers.
|
| 447 |
|
| 448 | static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
|
| 449 | ktime_t now)
|
| 450 | {
|
| 451 | struct k_itimer *ptr = container_of(alarm, struct k_itimer,
|
| 452 | it.alarm.alarmtimer);
|
| 453 | if (posix_timer_event(ptr, 0) != 0)
|
| 454 | ptr->it_overrun++;
|
| 455 |
|
| 456 |
|
| 457 | if (ptr->it.alarm.interval.tv64) {
|
| 458 | ptr->it_overrun += alarm_forward(alarm, now,
|
| 459 | ptr->it.alarm.interval);
|
| 460 | return ALARMTIMER_RESTART;
|
| 461 | }
|
| 462 | return ALARMTIMER_NORESTART;
|
| 463 | }
|
| 464 |
|
| 465 | |
| 466 | * alarm_clock_getres - posix getres interface
|
| 467 | * @which_clock: clockid
|
| 468 | * @tp: timespec to fill
|
| 469 | *
|
| 470 | * Returns the granularity of underlying alarm base clock
|
| 471 |
|
| 472 | static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
|
| 473 | {
|
| 474 | clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
|
| 475 |
|
| 476 | if (!alarmtimer_get_rtcdev())
|
| 477 | return -ENOTSUPP;
|
| 478 |
|
| 479 | return hrtimer_get_res(baseid, tp);
|
| 480 | }
|
| 481 |
|
| 482 | |
| 483 | * alarm_clock_get - posix clock_get interface
|
| 484 | * @which_clock: clockid
|
| 485 | * @tp: timespec to fill.
|
| 486 | *
|
| 487 | * Provides the underlying alarm base time.
|
| 488 |
|
| 489 | static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
|
| 490 | {
|
| 491 | struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
|
| 492 |
|
| 493 | if (!alarmtimer_get_rtcdev())
|
| 494 | return -ENOTSUPP;
|
| 495 |
|
| 496 | *tp = ktime_to_timespec(base->gettime());
|
| 497 | return 0;
|
| 498 | }
|
| 499 |
|
| 500 | |
| 501 | * alarm_timer_create - posix timer_create interface
|
| 502 | * @new_timer: k_itimer pointer to manage
|
| 503 | *
|
| 504 | * Initializes the k_itimer structure.
|
| 505 |
|
| 506 | static int alarm_timer_create(struct k_itimer *new_timer)
|
| 507 | {
|
| 508 | enum alarmtimer_type type;
|
| 509 | struct alarm_base *base;
|
| 510 |
|
| 511 | if (!alarmtimer_get_rtcdev())
|
| 512 | return -ENOTSUPP;
|
| 513 |
|
| 514 | if (!capable(CAP_WAKE_ALARM))
|
| 515 | return -EPERM;
|
| 516 |
|
| 517 | type = clock2alarm(new_timer->it_clock);
|
| 518 | base = &alarm_bases[type];
|
| 519 | alarm_init(&new_timer->it.alarm.alarmtimer, type, alarm_handle_timer);
|
| 520 | return 0;
|
| 521 | }
|
| 522 |
|
| 523 | |
| 524 | * alarm_timer_get - posix timer_get interface
|
| 525 | * @new_timer: k_itimer pointer
|
| 526 | * @cur_setting: itimerspec data to fill
|
| 527 | *
|
| 528 | * Copies the itimerspec data out from the k_itimer
|
| 529 |
|
| 530 | static void alarm_timer_get(struct k_itimer *timr,
|
| 531 | struct itimerspec *cur_setting)
|
| 532 | {
|
| 533 | memset(cur_setting, 0, sizeof(struct itimerspec));
|
| 534 |
|
| 535 | cur_setting->it_interval =
|
| 536 | ktime_to_timespec(timr->it.alarm.interval);
|
| 537 | cur_setting->it_value =
|
| 538 | ktime_to_timespec(timr->it.alarm.alarmtimer.node.expires);
|
| 539 | return;
|
| 540 | }
|
| 541 |
|
| 542 | |
| 543 | * alarm_timer_del - posix timer_del interface
|
| 544 | * @timr: k_itimer pointer to be deleted
|
| 545 | *
|
| 546 | * Cancels any programmed alarms for the given timer.
|
| 547 |
|
| 548 | static int alarm_timer_del(struct k_itimer *timr)
|
| 549 | {
|
| 550 | if (!rtcdev)
|
| 551 | return -ENOTSUPP;
|
| 552 |
|
| 553 | if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
|
| 554 | return TIMER_RETRY;
|
| 555 |
|
| 556 | return 0;
|
| 557 | }
|
| 558 |
|
| 559 | |
| 560 | * alarm_timer_set - posix timer_set interface
|
| 561 | * @timr: k_itimer pointer to be deleted
|
| 562 | * @flags: timer flags
|
| 563 | * @new_setting: itimerspec to be used
|
| 564 | * @old_setting: itimerspec being replaced
|
| 565 | *
|
| 566 | * Sets the timer to new_setting, and starts the timer.
|
| 567 |
|
| 568 | static int alarm_timer_set(struct k_itimer *timr, int flags,
|
| 569 | struct itimerspec *new_setting,
|
| 570 | struct itimerspec *old_setting)
|
| 571 | {
|
| 572 | if (!rtcdev)
|
| 573 | return -ENOTSUPP;
|
| 574 |
|
| 575 | if (old_setting)
|
| 576 | alarm_timer_get(timr, old_setting);
|
| 577 |
|
| 578 |
|
| 579 | if (alarm_try_to_cancel(&timr->it.alarm.alarmtimer) < 0)
|
| 580 | return TIMER_RETRY;
|
| 581 |
|
| 582 |
|
| 583 | timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
|
| 584 | alarm_start(&timr->it.alarm.alarmtimer,
|
| 585 | timespec_to_ktime(new_setting->it_value));
|
| 586 | return 0;
|
| 587 | }
|
| 588 |
|
| 589 | |
| 590 | * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep
|
| 591 | * @alarm: ptr to alarm that fired
|
| 592 | *
|
| 593 | * Wakes up the task that set the alarmtimer
|
| 594 |
|
| 595 | static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm,
|
| 596 | ktime_t now)
|
| 597 | {
|
| 598 | struct task_struct *task = (struct task_struct *)alarm->data;
|
| 599 |
|
| 600 | alarm->data = NULL;
|
| 601 | if (task)
|
| 602 | wake_up_process(task);
|
| 603 | return ALARMTIMER_NORESTART;
|
| 604 | }
|
| 605 |
|
| 606 | |
| 607 | * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation
|
| 608 | * @alarm: ptr to alarmtimer
|
| 609 | * @absexp: absolute expiration time
|
| 610 | *
|
| 611 | * Sets the alarm timer and sleeps until it is fired or interrupted.
|
| 612 |
|
| 613 | static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp)
|
| 614 | {
|
| 615 | alarm->data = (void *)current;
|
| 616 | do {
|
| 617 | set_current_state(TASK_INTERRUPTIBLE);
|
| 618 | alarm_start(alarm, absexp);
|
| 619 | if (likely(alarm->data))
|
| 620 | schedule();
|
| 621 |
|
| 622 | alarm_cancel(alarm);
|
| 623 | } while (alarm->data && !signal_pending(current));
|
| 624 |
|
| 625 | __set_current_state(TASK_RUNNING);
|
| 626 |
|
| 627 | return (alarm->data == NULL);
|
| 628 | }
|
| 629 |
|
| 630 |
|
| 631 | |
| 632 | * update_rmtp - Update remaining timespec value
|
| 633 | * @exp: expiration time
|
| 634 | * @type: timer type
|
| 635 | * @rmtp: user pointer to remaining timepsec value
|
| 636 | *
|
| 637 | * Helper function that fills in rmtp value with time between
|
| 638 | * now and the exp value
|
| 639 |
|
| 640 | static int update_rmtp(ktime_t exp, enum alarmtimer_type type,
|
| 641 | struct timespec __user *rmtp)
|
| 642 | {
|
| 643 | struct timespec rmt;
|
| 644 | ktime_t rem;
|
| 645 |
|
| 646 | rem = ktime_sub(exp, alarm_bases[type].gettime());
|
| 647 |
|
| 648 | if (rem.tv64 <= 0)
|
| 649 | return 0;
|
| 650 | rmt = ktime_to_timespec(rem);
|
| 651 |
|
| 652 | if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
|
| 653 | return -EFAULT;
|
| 654 |
|
| 655 | return 1;
|
| 656 |
|
| 657 | }
|
| 658 |
|
| 659 | |
| 660 | * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep
|
| 661 | * @restart: ptr to restart block
|
| 662 | *
|
| 663 | * Handles restarted clock_nanosleep calls
|
| 664 |
|
| 665 | static long __sched alarm_timer_nsleep_restart(struct restart_block *restart)
|
| 666 | {
|
| 667 | enum alarmtimer_type type = restart->nanosleep.clockid;
|
| 668 | ktime_t exp;
|
| 669 | struct timespec __user *rmtp;
|
| 670 | struct alarm alarm;
|
| 671 | int ret = 0;
|
| 672 |
|
| 673 | exp.tv64 = restart->nanosleep.expires;
|
| 674 | alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
|
| 675 |
|
| 676 | if (alarmtimer_do_nsleep(&alarm, exp))
|
| 677 | goto out;
|
| 678 |
|
| 679 | if (freezing(current))
|
| 680 | alarmtimer_freezerset(exp, type);
|
| 681 |
|
| 682 | rmtp = restart->nanosleep.rmtp;
|
| 683 | if (rmtp) {
|
| 684 | ret = update_rmtp(exp, type, rmtp);
|
| 685 | if (ret <= 0)
|
| 686 | goto out;
|
| 687 | }
|
| 688 |
|
| 689 |
|
| 690 |
|
| 691 | ret = -ERESTART_RESTARTBLOCK;
|
| 692 | out:
|
| 693 | return ret;
|
| 694 | }
|
| 695 |
|
| 696 | |
| 697 | * alarm_timer_nsleep - alarmtimer nanosleep
|
| 698 | * @which_clock: clockid
|
| 699 | * @flags: determins abstime or relative
|
| 700 | * @tsreq: requested sleep time (abs or rel)
|
| 701 | * @rmtp: remaining sleep time saved
|
| 702 | *
|
| 703 | * Handles clock_nanosleep calls against _ALARM clockids
|
| 704 |
|
| 705 | static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
|
| 706 | struct timespec *tsreq, struct timespec __user *rmtp)
|
| 707 | {
|
| 708 | enum alarmtimer_type type = clock2alarm(which_clock);
|
| 709 | struct alarm alarm;
|
| 710 | ktime_t exp;
|
| 711 | int ret = 0;
|
| 712 | struct restart_block *restart;
|
| 713 |
|
| 714 | if (!alarmtimer_get_rtcdev())
|
| 715 | return -ENOTSUPP;
|
| 716 |
|
| 717 | if (!capable(CAP_WAKE_ALARM))
|
| 718 | return -EPERM;
|
| 719 |
|
| 720 | alarm_init(&alarm, type, alarmtimer_nsleep_wakeup);
|
| 721 |
|
| 722 | exp = timespec_to_ktime(*tsreq);
|
| 723 |
|
| 724 | if (flags != TIMER_ABSTIME) {
|
| 725 | ktime_t now = alarm_bases[type].gettime();
|
| 726 | exp = ktime_add(now, exp);
|
| 727 | }
|
| 728 |
|
| 729 | if (alarmtimer_do_nsleep(&alarm, exp))
|
| 730 | goto out;
|
| 731 |
|
| 732 | if (freezing(current))
|
| 733 | alarmtimer_freezerset(exp, type);
|
| 734 |
|
| 735 |
|
| 736 | if (flags == TIMER_ABSTIME) {
|
| 737 | ret = -ERESTARTNOHAND;
|
| 738 | goto out;
|
| 739 | }
|
| 740 |
|
| 741 | if (rmtp) {
|
| 742 | ret = update_rmtp(exp, type, rmtp);
|
| 743 | if (ret <= 0)
|
| 744 | goto out;
|
| 745 | }
|
| 746 |
|
| 747 | restart = ¤t_thread_info()->restart_block;
|
| 748 | restart->fn = alarm_timer_nsleep_restart;
|
| 749 | restart->nanosleep.clockid = type;
|
| 750 | restart->nanosleep.expires = exp.tv64;
|
| 751 | restart->nanosleep.rmtp = rmtp;
|
| 752 | ret = -ERESTART_RESTARTBLOCK;
|
| 753 |
|
| 754 | out:
|
| 755 | return ret;
|
| 756 | }
|
| 757 |
|
| 758 |
|
| 759 |
|
| 760 | static const struct dev_pm_ops alarmtimer_pm_ops = {
|
| 761 | .suspend = alarmtimer_suspend,
|
| 762 | };
|
| 763 |
|
| 764 | static struct platform_driver alarmtimer_driver = {
|
| 765 | .driver = {
|
| 766 | .name = "alarmtimer",
|
| 767 | .pm = &alarmtimer_pm_ops,
|
| 768 | }
|
| 769 | };
|
| 770 |
|
| 771 | |
| 772 | * alarmtimer_init - Initialize alarm timer code
|
| 773 | *
|
| 774 | * This function initializes the alarm bases and registers
|
| 775 | * the posix clock ids.
|
| 776 |
|
| 777 | static int __init alarmtimer_init(void)
|
| 778 | {
|
| 779 | struct platform_device *pdev;
|
| 780 | int error = 0;
|
| 781 | int i;
|
| 782 | struct k_clock alarm_clock = {
|
| 783 | .clock_getres = alarm_clock_getres,
|
| 784 | .clock_get = alarm_clock_get,
|
| 785 | .timer_create = alarm_timer_create,
|
| 786 | .timer_set = alarm_timer_set,
|
| 787 | .timer_del = alarm_timer_del,
|
| 788 | .timer_get = alarm_timer_get,
|
| 789 | .nsleep = alarm_timer_nsleep,
|
| 790 | };
|
| 791 |
|
| 792 | alarmtimer_rtc_timer_init();
|
| 793 |
|
| 794 | posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
|
| 795 | posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
|
| 796 |
|
| 797 |
|
| 798 | alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
|
| 799 | alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
|
| 800 | alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
|
| 801 | alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
|
| 802 | for (i = 0; i < ALARM_NUMTYPE; i++) {
|
| 803 | timerqueue_init_head(&alarm_bases[i].timerqueue);
|
| 804 | spin_lock_init(&alarm_bases[i].lock);
|
| 805 | hrtimer_init(&alarm_bases[i].timer,
|
| 806 | alarm_bases[i].base_clockid,
|
| 807 | HRTIMER_MODE_ABS);
|
| 808 | alarm_bases[i].timer.function = alarmtimer_fired;
|
| 809 | }
|
| 810 |
|
| 811 | error = alarmtimer_rtc_interface_setup();
|
| 812 | if (error)
|
| 813 | return error;
|
| 814 |
|
| 815 | error = platform_driver_register(&alarmtimer_driver);
|
| 816 | if (error)
|
| 817 | goto out_if;
|
| 818 |
|
| 819 | pdev = platform_device_register_simple("alarmtimer", -1, NULL, 0);
|
| 820 | if (IS_ERR(pdev)) {
|
| 821 | error = PTR_ERR(pdev);
|
| 822 | goto out_drv;
|
| 823 | }
|
| 824 | return 0;
|
| 825 |
|
| 826 | out_drv:
|
| 827 | platform_driver_unregister(&alarmtimer_driver);
|
| 828 | out_if:
|
| 829 | alarmtimer_rtc_interface_remove();
|
| 830 | return error;
|
| 831 | }
|
| 832 | device_initcall(alarmtimer_init);
|