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/*
* Copyright (c) 1996-1999 University of Utah and the Flux Group.
* All rights reserved.
*
* This file is part of the Flux OSKit. The OSKit is free software, also known
* as "open source;" you can redistribute it and/or modify it under the terms
* of the GNU General Public License (GPL), version 2, as published by the Free
* Software Foundation (FSF). To explore alternate licensing terms, contact
* the University of Utah at csl-dist@cs.utah.edu or +1-801-585-3271.
*
* The OSKit 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 GPL for more details. You should have
* received a copy of the GPL along with the OSKit; see the file COPYING. If
* not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA.
*/
/*
* Timer interrupt support.
*/
#include <oskit/dev/dev.h>
#include <oskit/debug.h>
#include <oskit/arm32/pio.h>
#include <oskit/arm32/proc_reg.h>
#include "pit_param.h"
#define NTIMERS 10
#define TIMER_FREQ 100
#define TIMER_VALUE (PIT_HZ / TIMER_FREQ)
/* Prototypes for helper functions in another file */
int osenv_timer_pit_init(int freq, void (*timer_intr)());
void osenv_timer_pit_shutdown();
int osenv_timer_pit_read();
struct timer_handler {
void (*func)(void);
struct timer_handler *next;
};
static struct timer_handler *timer_head, *timer_free;
static struct timer_handler timer_data[NTIMERS];
/*
* Generic timer interrupt handler.
*/
static void
timer_intr()
{
struct timer_handler *th;
for (th = timer_head; th; th = th->next)
(*th->func)();
}
/*
* Initialize timers.
*/
void
osenv_timer_init()
{
static int initialized = 0; /* guard against multiple invocations */
int i;
if (initialized)
return;
initialized = 1;
for (i = 0; i < NTIMERS; i++)
timer_data[i].next = &timer_data[i + 1];
timer_data[NTIMERS - 1].next = 0;
timer_free = &timer_data[0];
/*
* Install interrupt handler at TIMER_FREQ Hz.
*/
oskit_timer_rtc_init(TIMER_FREQ, timer_intr);
}
/*
* Turn all timers off.
*/
void
osenv_timer_shutdown()
{
osenv_log(OSENV_LOG_DEBUG, "Shutting down timer\n");
oskit_timer_rtc_shutdown();
}
/*
* Register a timer handler to be called at the specified frequency.
*/
void
osenv_timer_register(void (*func)(void), int freq)
{
struct timer_handler *th;
unsigned int flags;
/* XXX */
osenv_timer_init();
if (timer_free == 0)
osenv_panic("%s:%d: ran out of entries", __FILE__, __LINE__);
/*
* XXX
*/
if (freq != TIMER_FREQ)
osenv_panic("%s:%d: bad freq", __FILE__, __LINE__);
if (func == 0)
osenv_panic("%s:%d: null function", __FILE__, __LINE__);
flags = osenv_intr_enabled();
osenv_intr_disable();
th = timer_free;
timer_free = th->next;
th->next = timer_head;
timer_head = th;
th->func = func;
if (flags)
osenv_intr_enable();
}
/*
* Frequency and function address uniquely identify which to remove since
* equal values are equivelent.
*/
void
osenv_timer_unregister(void (*func)(void), int freq)
{
int flags;
struct timer_handler *th, **prev;
if (freq != TIMER_FREQ)
osenv_panic("%s:%d: bad freq", __FILE__, __LINE__);
/* dissable interrupts while mucking with the queue */
flags = osenv_intr_enabled();
osenv_intr_disable();
/* move the timer from the run-queue to the unused-queue */
prev = &timer_head;
th = timer_head;
while (th && (th->func != func)) {
prev = &th->next;
th = th->next;
}
if (!th) {
osenv_log(OSENV_LOG_WARNING, "Timer handler not found\n");
} else {
/* have the active list skip over it */
*prev = th->next;
/* place in inactive queue */
th->next = timer_free;
timer_free = th;
}
if (flags)
osenv_intr_enable();
}
/*
* Spin for a small amount of time, specified in nanoseconds,
* without blocking or enabling interrupts.
*/
void
osenv_timer_spin(long nanosec)
{
int prev_val = osenv_timer_pit_read();
while (nanosec > 0) {
int val = osenv_timer_pit_read();
if (val > prev_val)
prev_val += TIMER_VALUE;
nanosec -= (prev_val - val) * PIT_NS;
prev_val = val;
}
}
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