// 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 <[email protected]> */ #include <linux/time.h> #include <linux/hrtimer.h> #include <linux/timerqueue.h> #include <linux/rtc.h> #include <linux/sched/signal.h> #include <linux/sched/debug.h> #include <linux/alarmtimer.h> #include <linux/mutex.h> #include <linux/platform_device.h> #include <linux/posix-timers.h> #include <linux/workqueue.h> #include <linux/freezer.h> #include <linux/compat.h> #include <linux/module.h> #include <linux/time_namespace.h> #include "posix-timers.h" #define CREATE_TRACE_POINTS #include <trace/events/alarmtimer.h> /** * 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 { … } 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) { … } EXPORT_SYMBOL_GPL(…); static int alarmtimer_rtc_add_device(struct device *dev) { … } static inline void alarmtimer_rtc_timer_init(void) { … } static struct class_interface alarmtimer_rtc_interface = …; static int alarmtimer_rtc_interface_setup(void) { … } static void alarmtimer_rtc_interface_remove(void) { … } #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) { … } /** * 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) { … } /** * 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) { … } ktime_t alarm_expires_remaining(const struct alarm *alarm) { … } EXPORT_SYMBOL_GPL(…); #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) { … } static int alarmtimer_resume(struct device *dev) { … } #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, enum alarmtimer_restart (*function)(struct alarm *, ktime_t)) { … } /** * 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, enum alarmtimer_restart (*function)(struct alarm *, ktime_t)) { … } EXPORT_SYMBOL_GPL(…); /** * 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) { … } EXPORT_SYMBOL_GPL(…); /** * 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) { … } EXPORT_SYMBOL_GPL(…); void alarm_restart(struct alarm *alarm) { … } EXPORT_SYMBOL_GPL(…); /** * 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) { … } EXPORT_SYMBOL_GPL(…); /** * 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) { … } EXPORT_SYMBOL_GPL(…); u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval) { … } EXPORT_SYMBOL_GPL(…); static u64 __alarm_forward_now(struct alarm *alarm, ktime_t interval, bool throttle) { … } u64 alarm_forward_now(struct alarm *alarm, ktime_t interval) { … } EXPORT_SYMBOL_GPL(…); #ifdef CONFIG_POSIX_TIMERS static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type) { … } /** * clock2alarm - helper that converts from clockid to alarmtypes * @clockid: clockid. */ static enum alarmtimer_type clock2alarm(clockid_t clockid) { … } /** * 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 enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm, ktime_t now) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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) { … } /** * 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 * * Return: ALARMTIMER_NORESTART */ static enum alarmtimer_restart alarmtimer_nsleep_wakeup(struct alarm *alarm, ktime_t now) { … } /** * 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) { … } static void alarm_init_on_stack(struct alarm *alarm, enum alarmtimer_type type, enum alarmtimer_restart (*function)(struct alarm *, ktime_t)) { … } /** * 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) { … } /** * 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) { … } const struct k_clock alarm_clock = …; #endif /* CONFIG_POSIX_TIMERS */ /* Suspend hook structures */ static const struct dev_pm_ops alarmtimer_pm_ops = …; static struct platform_driver alarmtimer_driver = …; static void get_boottime_timespec(struct timespec64 *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) { … } device_initcall(alarmtimer_init);
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