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/* timer.c - A timer module for Mach.
Copyright (C) 1995,96,2000,02 Free Software Foundation, Inc.
Written by Michael I. Bushnell, p/BSG and Marcus Brinkmann.
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 2, 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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */
#include <errno.h>
#include <string.h>
#include <maptime.h>
#include <mach.h>
#include <pthread.h>
#include <stdio.h>
#include "timer.h"
/* The value of fetch_jiffies() at startup. */
long long timer_root_jiffies;
/* The mapped time. */
volatile struct mapped_time_value *timer_mapped_time;
/* The timer thread. */
static thread_t timer_thread;
/* The lock protects the timer list TIMERS. */
static pthread_mutex_t timer_lock;
/* A list of all active timers. */
static struct timer_list *timers;
static inline void
timer_add_internal (struct timer_list *timer)
{
struct timer_list **tp;
for (tp = &timers; *tp; tp = &(*tp)->next)
if ((*tp)->expires > timer->expires)
{
timer->next = *tp;
timer->next->prev = &timer->next;
timer->prev = tp;
*tp = timer;
break;
}
if (!*tp)
{
timer->next = 0;
timer->prev = tp;
*tp = timer;
}
}
/* Make the timer thread aware of new timers at the beginning of the
list. */
static inline void
kick_timer_thread (void)
{
/* XXX This is a whacky notion. */
while (!timer_thread)
swtch_pri (0);
if (timer_thread != mach_thread_self ())
{
thread_suspend (timer_thread);
thread_abort (timer_thread);
thread_resume (timer_thread);
}
}
/* The timer thread. */
static void *
timer_function (void *this_is_a_pointless_variable_with_a_rather_long_name)
{
mach_port_t recv = mach_reply_port ();
int wait = 0;
timer_thread = mach_thread_self ();
pthread_mutex_lock (&timer_lock);
while (1)
{
int jiff = fetch_jiffies ();
if (!timers)
wait = -1;
else if (timers->expires < jiff)
wait = 0;
else
wait = ((timers->expires - jiff) * 1000) / HZ;
pthread_mutex_unlock (&timer_lock);
mach_msg (NULL, (MACH_RCV_MSG | MACH_RCV_INTERRUPT
| (wait == -1 ? 0 : MACH_RCV_TIMEOUT)),
0, 0, recv, wait, MACH_PORT_NULL);
pthread_mutex_lock (&timer_lock);
while (timers && timers->expires < fetch_jiffies ())
{
struct timer_list *tp;
tp = timers;
timers = timers->next;
if (timers)
timers->prev = &timers;
tp->next = 0;
tp->prev = 0;
if ((*tp->fnc) (tp->fnc_data))
timer_add_internal (tp);
}
}
return NULL;
}
/* Initialize the timer component. Must be called once at startup. */
error_t
timer_init (void)
{
error_t err;
struct timeval tp;
pthread_t thread;
pthread_mutex_init (&timer_lock, NULL);
err = maptime_map (0, 0, &timer_mapped_time);
if (err)
return err;
maptime_read (timer_mapped_time, &tp);
timer_root_jiffies = (long long) tp.tv_sec * HZ
+ ((long long) tp.tv_usec * HZ) / 1000000;
err = pthread_create (&thread, NULL, timer_function, NULL);
if (!err)
pthread_detach (thread);
else
{
errno = err;
perror ("pthread_create");
}
return 0;
}
/* Initialize the timer TIMER. */
void
timer_clear (struct timer_list *timer)
{
memset (timer, 0, sizeof (struct timer_list));
}
/* Add the timer TIMER to the list. */
void
timer_add (struct timer_list *timer)
{
pthread_mutex_lock (&timer_lock);
timer_add_internal (timer);
if (timers == timer)
kick_timer_thread ();
pthread_mutex_unlock (&timer_lock);
}
/* Remove the timer TIMER from the list. */
int
timer_remove (struct timer_list *timer)
{
pthread_mutex_lock (&timer_lock);
if (timer->prev)
{
*timer->prev = timer->next;
if (timer->next)
timer->next->prev = timer->prev;
timer->next = 0;
timer->prev = 0;
pthread_mutex_unlock (&timer_lock);
return 1;
}
else
{
pthread_mutex_unlock (&timer_lock);
return 0;
}
}
/* Change the expiration time of the timer TIMER to EXPIRES. */
void
timer_change (struct timer_list *timer, long long expires)
{
/* XXX Should optimize this. */
timer_remove (timer);
timer->expires = expires;
timer_add (timer);
}
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