/*

 *  include/linux/hrtimer.h

 *

 *  hrtimers - High-resolution kernel timers

 *

 *   Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>

 *   Copyright(C) 2005, Red Hat, Inc., Ingo Molnar

 *

 *  data type definitions, declarations, prototypes

 *

 *  Started by: Thomas Gleixner and Ingo Molnar

 *

 *  For licencing details see kernel-base/COPYING

 */

#ifndef _LINUX_HRTIMER_H

#define _LINUX_HRTIMER_H

#include <linux/rbtree.h>

#include <linux/ktime.h>

#include <linux/init.h>

#include <linux/list.h>

#include <linux/wait.h>

#include <linux/percpu.h>

struct hrtimer_clock_base;

struct hrtimer_cpu_base;

/*

 * Mode arguments of xxx_hrtimer functions:

 */

enum hrtimer_mode {

	HRTIMER_MODE_ABS,	/* Time value is absolute */

	HRTIMER_MODE_REL,	/* Time value is relative to now */

};

/*

 * Return values for the callback function

 */

enum hrtimer_restart {

	HRTIMER_NORESTART,	/* Timer is not restarted */

	HRTIMER_RESTART,	/* Timer must be restarted */

};

/*

 * Values to track state of the timer

 *

 * Possible states:

 *

 * 0x00		inactive

 * 0x01		enqueued into rbtree

 * 0x02		callback function running

 *

 * Special cases:

 * 0x03		callback function running and enqueued

 *		(was requeued on another CPU)

 * 0x09		timer was migrated on CPU hotunplug

 * The "callback function running and enqueued" status is only possible on

 * SMP. It happens for example when a posix timer expired and the callback

 * queued a signal. Between dropping the lock which protects the posix timer

 * and reacquiring the base lock of the hrtimer, another CPU can deliver the

 * signal and rearm the timer. We have to preserve the callback running state,

 * as otherwise the timer could be removed before the softirq code finishes the

 * the handling of the timer.

 *

 * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state to

 * preserve the HRTIMER_STATE_CALLBACK bit in the above scenario.

 *

 * All state transitions are protected by cpu_base->lock.

 */

#define HRTIMER_STATE_INACTIVE	0x00

#define HRTIMER_STATE_ENQUEUED	0x01

#define HRTIMER_STATE_CALLBACK	0x02

/**

 * struct hrtimer - the basic hrtimer structure

 * @node:	red black tree node for time ordered insertion

 * @_expires:	the absolute expiry time in the hrtimers internal

 *		representation. The time is related to the clock on

 *		which the timer is based. Is setup by adding

 *		slack to the _softexpires value. For non range timers

 *		identical to _softexpires.

 * @_softexpires: the absolute earliest expiry time of the hrtimer.

 *		The time which was given as expiry time when the timer

 *		was armed.

 * @function:	timer expiry callback function

 * @base:	pointer to the timer base (per cpu and per clock)

 * @state:	state information (See bit values above)

 * @cb_entry:	list head to enqueue an expired timer into the callback list

 * @start_site:	timer statistics field to store the site where the timer

 *		was started

 * @start_comm: timer statistics field to store the name of the process which

 *		started the timer

 * @start_pid: timer statistics field to store the pid of the task which

 *		started the timer

 *

 * The hrtimer structure must be initialized by hrtimer_init()

 */

struct hrtimer {

	struct rb_node			node;

	ktime_t				_expires;

	ktime_t				_softexpires;

	enum hrtimer_restart		(*function)(struct hrtimer *);

	struct hrtimer_clock_base	*base;

	unsigned long			state;

	struct list_head		cb_entry;

#ifdef CONFIG_TIMER_STATS

	int				start_pid;

	void				*start_site;

	char				start_comm[16];

#endif

};

/**

 * struct hrtimer_sleeper - simple sleeper structure

 * @timer:	embedded timer structure

 * @task:	task to wake up

 *

 * task is set to NULL, when the timer expires.

 */

struct hrtimer_sleeper {

	struct hrtimer timer;

	struct task_struct *task;

};

/**

 * struct hrtimer_clock_base - the timer base for a specific clock

 * @cpu_base:		per cpu clock base

 * @index:		clock type index for per_cpu support when moving a

 *			timer to a base on another cpu.

 * @active:		red black tree root node for the active timers

 * @first:		pointer to the timer node which expires first

 * @resolution:		the resolution of the clock, in nanoseconds

 * @get_time:		function to retrieve the current time of the clock

 * @softirq_time:	the time when running the hrtimer queue in the softirq

 * @offset:		offset of this clock to the monotonic base

 */

struct hrtimer_clock_base {

	struct hrtimer_cpu_base	*cpu_base;

	clockid_t		index;

	struct rb_root		active;

	struct rb_node		*first;

	ktime_t			resolution;

	ktime_t			(*get_time)(void);

	ktime_t			softirq_time;

#ifdef CONFIG_HIGH_RES_TIMERS

	ktime_t			offset;

#endif

};

#define HRTIMER_MAX_CLOCK_BASES 2

/*

 * struct hrtimer_cpu_base - the per cpu clock bases

 * @lock:		lock protecting the base and associated clock bases

 *			and timers

 * @clock_base:		array of clock bases for this cpu

 * @curr_timer:		the timer which is executing a callback right now

 * @expires_next:	absolute time of the next event which was scheduled

 *			via clock_set_next_event()

 * @hres_active:	State of high resolution mode

 * @check_clocks:	Indictator, when set evaluate time source and clock

 *			event devices whether high resolution mode can be

 *			activated.

 * @nr_events:		Total number of timer interrupt events

 */

struct hrtimer_cpu_base {

	spinlock_t			lock;

	struct hrtimer_clock_base	clock_base[HRTIMER_MAX_CLOCK_BASES];

#ifdef CONFIG_HIGH_RES_TIMERS

	ktime_t				expires_next;

	int				hres_active;

	unsigned long			nr_events;

#endif

};

static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)

{

	timer->_expires = time;

	timer->_softexpires = time;

}

static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)

{

	timer->_softexpires = time;

	timer->_expires = ktime_add_safe(time, delta);

}

static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta)

{

	timer->_softexpires = time;

	timer->_expires = ktime_add_safe(time, ns_to_ktime(delta));

}

static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)

{

	timer->_expires.tv64 = tv64;

	timer->_softexpires.tv64 = tv64;

}

static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)

{

	timer->_expires = ktime_add_safe(timer->_expires, time);

	timer->_softexpires = ktime_add_safe(timer->_softexpires, time);

}

static inline void hrtimer_add_expires_ns(struct hrtimer *timer, u64 ns)

{

	timer->_expires = ktime_add_ns(timer->_expires, ns);

	timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);

}

static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)

{

	return timer->_expires;

}

static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)

{

	return timer->_softexpires;

}

static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)

{

	return timer->_expires.tv64;

}

static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)

{

	return timer->_softexpires.tv64;

}

static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)

{

	return ktime_to_ns(timer->_expires);

}

static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)

{

    return ktime_sub(timer->_expires, timer->base->get_time());

}

#ifdef CONFIG_HIGH_RES_TIMERS

struct clock_event_device;

extern void clock_was_set(void);

extern void hres_timers_resume(void);

extern void hrtimer_interrupt(struct clock_event_device *dev);

/*

 * In high resolution mode the time reference must be read accurate

 */

static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)

{

	return timer->base->get_time();

}

static inline int hrtimer_is_hres_active(struct hrtimer *timer)

{

	return timer->base->cpu_base->hres_active;

}

extern void hrtimer_peek_ahead_timers(void);

/*

 * The resolution of the clocks. The resolution value is returned in

 * the clock_getres() system call to give application programmers an

 * idea of the (in)accuracy of timers. Timer values are rounded up to

 * this resolution values.

 */

# define HIGH_RES_NSEC		1

# define KTIME_HIGH_RES		(ktime_t) { .tv64 = HIGH_RES_NSEC }

# define MONOTONIC_RES_NSEC	HIGH_RES_NSEC

# define KTIME_MONOTONIC_RES	KTIME_HIGH_RES

#else

# define MONOTONIC_RES_NSEC	LOW_RES_NSEC

# define KTIME_MONOTONIC_RES	KTIME_LOW_RES

/*

 * clock_was_set() is a NOP for non- high-resolution systems. The

 * time-sorted order guarantees that a timer does not expire early and

 * is expired in the next softirq when the clock was advanced.

 */

static inline void clock_was_set(void) { }

static inline void hrtimer_peek_ahead_timers(void) { }

static inline void hres_timers_resume(void) { }

/*

 * In non high resolution mode the time reference is taken from

 * the base softirq time variable.

 */

static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)

{

	return timer->base->softirq_time;

}

static inline int hrtimer_is_hres_active(struct hrtimer *timer)

{

	return 0;

}

#endif

extern ktime_t ktime_get(void);

extern ktime_t ktime_get_real(void);

DECLARE_PER_CPU(struct tick_device, tick_cpu_device);

/* Exported timer functions: */

/* Initialize timers: */

extern void hrtimer_init(struct hrtimer *timer, clockid_t which_clock,

			 enum hrtimer_mode mode);

#ifdef CONFIG_DEBUG_OBJECTS_TIMERS

extern void hrtimer_init_on_stack(struct hrtimer *timer, clockid_t which_clock,

				  enum hrtimer_mode mode);

extern void destroy_hrtimer_on_stack(struct hrtimer *timer);

#else

static inline void hrtimer_init_on_stack(struct hrtimer *timer,

					 clockid_t which_clock,

					 enum hrtimer_mode mode)

{

	hrtimer_init(timer, which_clock, mode);

}

static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }

#endif

/* Basic timer operations: */

extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,

			 const enum hrtimer_mode mode);

extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,

			unsigned long range_ns, const enum hrtimer_mode mode);

extern int hrtimer_cancel(struct hrtimer *timer);

extern int hrtimer_try_to_cancel(struct hrtimer *timer);

static inline int hrtimer_start_expires(struct hrtimer *timer,

						enum hrtimer_mode mode)

{

	unsigned long delta;

	ktime_t soft, hard;

	soft = hrtimer_get_softexpires(timer);

	hard = hrtimer_get_expires(timer);

	delta = ktime_to_ns(ktime_sub(hard, soft));

	return hrtimer_start_range_ns(timer, soft, delta, mode);

}

static inline int hrtimer_restart(struct hrtimer *timer)

{

	return hrtimer_start_expires(timer, HRTIMER_MODE_ABS);

}

/* Query timers: */

extern ktime_t hrtimer_get_remaining(const struct hrtimer *timer);

extern int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp);

extern ktime_t hrtimer_get_next_event(void);

/*

 * A timer is active, when it is enqueued into the rbtree or the callback

 * function is running.

 */

static inline int hrtimer_active(const struct hrtimer *timer)

{

	return timer->state != HRTIMER_STATE_INACTIVE;

}

/*

 * Helper function to check, whether the timer is on one of the queues

 */

static inline int hrtimer_is_queued(struct hrtimer *timer)

{

}

/*

 * Helper function to check, whether the timer is running the callback

 * function

 */

static inline int hrtimer_callback_running(struct hrtimer *timer)

{

	return timer->state & HRTIMER_STATE_CALLBACK;

}

/* Forward a hrtimer so it expires after now: */

extern u64

hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);

/* Forward a hrtimer so it expires after the hrtimer's current now */

static inline u64 hrtimer_forward_now(struct hrtimer *timer,

				      ktime_t interval)

{

	return hrtimer_forward(timer, timer->base->get_time(), interval);

}

/* Precise sleep: */

extern long hrtimer_nanosleep(struct timespec *rqtp,

			      struct timespec __user *rmtp,

			      const enum hrtimer_mode mode,

			      const clockid_t clockid);

extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);

extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,

				 struct task_struct *tsk);

extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,

						const enum hrtimer_mode mode);

extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);

/* Soft interrupt function to run the hrtimer queues: */

extern void hrtimer_run_queues(void);

extern void hrtimer_run_pending(void);

/* Bootup initialization: */

extern void __init hrtimers_init(void);

#if BITS_PER_LONG < 64

extern u64 ktime_divns(const ktime_t kt, s64 div);

#else /* BITS_PER_LONG < 64 */

# define ktime_divns(kt, div)		(u64)((kt).tv64 / (div))

#endif

/* Show pending timers: */

extern void sysrq_timer_list_show(void);

/*

 * Timer-statistics info:

 */

#ifdef CONFIG_TIMER_STATS

extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,

				     void *timerf, char *comm,

				     unsigned int timer_flag);

static inline void timer_stats_account_hrtimer(struct hrtimer *timer)

{

	timer_stats_update_stats(timer, timer->start_pid, timer->start_site,

				 timer->function, timer->start_comm, 0);

}

extern void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer,

						 void *addr);

static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)

{

	__timer_stats_hrtimer_set_start_info(timer, __builtin_return_address(0));

}

static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)

{

	timer->start_site = NULL;

}

#else

static inline void timer_stats_account_hrtimer(struct hrtimer *timer)

{

}

static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)

{

}

static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)

{

}

#endif

#endif