platform/armemu/timer.c

/*
 * Copyright (c) 2008 Travis Geiselbrecht
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files
 * (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
#include <sys/types.h>
#include <err.h>
#include <kernel/thread.h>
#include <platform.h>
#include <platform/interrupts.h>
#include <platform/timer.h>
#include <platform/armemu.h>
#include "platform_p.h"

static platform_timer_callback t_callback;

status_t platform_set_periodic_timer(platform_timer_callback callback, void *arg, time_t interval)
{
	enter_critical_section();

	t_callback = callback;

	*REG(PIT_CLEAR) = 1;
	*REG(PIT_INTERVAL) = interval;
	*REG(PIT_START_PERIODIC) = 1;

	unmask_interrupt(INT_PIT, NULL);

	exit_critical_section();

	return NO_ERROR;
}

time_t current_time(void)
{
	time_t time;
	*REG(SYSINFO_TIME_LATCH) = 1;
	time = *REG(SYSINFO_TIME_SECS) * 1000;
	time += *REG(SYSINFO_TIME_USECS) / 1000;
			
	return time;
}

static enum handler_return platform_tick(void *arg)
{
	*REG(PIT_CLEAR_INT) = 1;
	if (t_callback) {
		return t_callback(arg, current_time());
	} else {
		return INT_NO_RESCHEDULE;
	}
}

void platform_init_timer(void)
{
	register_int_handler(INT_PIT, &platform_tick, NULL);
}