/******************************************************************************

 * timer.h

 * 

 * Copyright (c) 2002-2003 Rolf Neugebauer

 * Copyright (c) 2002-2005 K A Fraser

 */

#ifndef _TIMER_H_

#define _TIMER_H_

#include <xen/spinlock.h>

#include <xen/time.h>

#include <xen/string.h>

#include <xen/list.h>

#include <xen/percpu.h>

struct timer {

    /* System time expiry value (nanoseconds since boot). */

    s_time_t expires;

    /* Position in active-timer data structure. */

    union {

        /* Timer-heap offset (TIMER_STATUS_in_heap). */

        unsigned int heap_offset;

        /* Linked list (TIMER_STATUS_in_list). */

        struct timer *list_next;

        /* Linked list of inactive timers (TIMER_STATUS_inactive). */

        struct list_head inactive;

    };

    /* On expiry, '(*function)(data)' will be executed in softirq context. */

    void (*function)(void *);

    void *data;

    /* CPU on which this timer will be installed and executed. */

#define TIMER_CPU_status_killed 0xffffu /* Timer is TIMER_STATUS_killed */

    uint16_t cpu;

    /* Timer status. */

#define TIMER_STATUS_invalid  0 /* Should never see this.           */

#define TIMER_STATUS_inactive 1 /* Not in use; can be activated.    */

#define TIMER_STATUS_killed   2 /* Not in use; cannot be activated. */

#define TIMER_STATUS_in_heap  3 /* In use; on timer heap.           */

#define TIMER_STATUS_in_list  4 /* In use; on overflow linked list. */

    uint8_t status;

};

/*

 * All functions below can be called for any CPU from any CPU in any context.

 */

/*

 * Initialise a timer structure with an initial callback CPU, callback

 * function and callback data pointer. This function must only be called on

 * a brand new timer, or a killed timer. It must *never* execute concurrently

 * with any other operation on the same timer.

 */

void init_timer(

    struct timer *timer,

    void        (*function)(void *),

    void         *data,

    unsigned int  cpu);

/* Set the expiry time and activate a timer. */

void set_timer(struct timer *timer, s_time_t expires);

/*

 * Deactivate a timer This function has no effect if the timer is not currently

 * active.

 */

void stop_timer(struct timer *timer);

/* True if a timer is active, and its expiry time is earlier than t. */

bool timer_expires_before(struct timer *timer, s_time_t t);

#define timer_is_expired(t) timer_expires_before(t, NOW())

/* Migrate a timer to a different CPU. The timer may be currently active. */

void migrate_timer(struct timer *timer, unsigned int new_cpu);

/*

 * Deactivate a timer and prevent it from being re-set (future calls to

 * set_timer will silently fail). When this function returns it is guaranteed

 * that the timer callback handler is not running on any CPU.

 */

void kill_timer(struct timer *timer);

/* Bootstrap initialisation. Must be called before any other timer function. */

void timer_init(void);

/* Next timer deadline for each CPU. */

DECLARE_PER_CPU(s_time_t, timer_deadline);

/* Arch-defined function to reprogram timer hardware for new deadline. */

int reprogram_timer(s_time_t timeout);

/* Calculate the aligned first tick time for a given periodic timer. */

s_time_t align_timer(s_time_t firsttick, uint64_t period);

#endif /* _TIMER_H_ */

/*

 * Local variables:

 * mode: C

 * c-file-style: "BSD"

 * c-basic-offset: 4

 * tab-width: 4

 * indent-tabs-mode: nil

 * End:

 */