/* timer.h - Timer interface.
   Copyright (C) 2009 Free Software Foundation, Inc.
   Written by Neal H. Walfield <neal@gnu.org>.

   This file is part of the GNU Hurd.

   The GNU Hurd is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 3 of the
   License, or (at your option) any later version.

   The GNU Hurd is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see
   <http://www.gnu.org/licenses/>.  */

#ifndef _VIENGOOS_TIMER_H
#define _VIENGOOS_TIMER_H 1

#include <stdint.h>
#include <stdbool.h>
#include <hurd/stddef.h>
#include <viengoos/bits/sys.h>

extern volatile struct vg_time time_data;

struct timer
{
  struct timer *next;
  struct timer *prev;
  void (*callback) (struct timer *timer);
  uint64_t expire;
};

/* Register a timer.  TIMER->EXPIRE and TIMER->CALLBACK must be
   correctly initialized prior to calling this function.  */
extern void timer_register (struct timer *timer);

/* Cancel a previously registered and as of yet unfired timer.  */
extern void timer_cancel (struct timer *timer);

static inline void
timer_check (void)
{
  extern bool timer_bottom_half_pending;
  extern struct timer *timers;

  if (timers && unlikely (timers->expire <= time_data.ns_since_boot)
      && ! timer_bottom_half_pending)
    {
      extern void timer_check_hard (void);

      timer_check_hard ();
    }
}

extern void timer_bootstrap (void);

#endif