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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2009 Samsung Electronics
*
* This program 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; version 2 of the License.
*
* This program 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <console/console.h>
#include <arch/io.h>
#include <timer.h>
#include <delay.h>
#include "timer.h"
#include "pwm.h"
#include "clk.h"
#include "cpu.h"
static unsigned long long timer_reset_value;
static unsigned long lastinc;
/* macro to read the 16 bit timer */
static inline struct s5p_timer *s5p_get_base_timer(void)
{
return samsung_get_base_timer();
}
/**
* Read the countdown timer.
*
* This operates at 1MHz and counts downwards. It will wrap about every
* hour (2^32 microseconds).
*
* @return current value of timer
*/
static unsigned long timer_get_us_down(void)
{
struct s5p_timer *const timer = s5p_get_base_timer();
return readl(&timer->tcnto4);
}
void init_timer(void)
{
/* Timer may have been enabled in SPL */
if (!pwm_check_enabled(4)) {
/* PWM Timer 4 */
pwm_init(4, MUX_DIV_4, 0);
pwm_config(4, 100000, 100000);
pwm_enable(4);
/* Use this as the current monotonic time in us */
timer_reset_value = 0;
/* Use this as the last timer value we saw */
lastinc = timer_get_us_down();
}
}
/*
* timer without interrupts
*/
unsigned long get_timer(unsigned long base)
{
unsigned long now = timer_get_us_down();
/*
* Increment the time by the amount elapsed since the last read.
* The timer may have wrapped around, but it makes no difference to
* our arithmetic here.
*/
timer_reset_value += lastinc - now;
lastinc = now;
/* Divide by 1000 to convert from us to ms */
return timer_reset_value / 1000 - base;
}
/* delay x useconds */
void udelay(unsigned usec)
{
struct mono_time current, end;
timer_monotonic_get(¤t);
end = current;
mono_time_add_usecs(&end, usec);
if (mono_time_after(¤t, &end)) {
printk(BIOS_EMERG, "udelay: 0x%08x is impossibly large\n",
usec);
/* There's not much we can do if usec is too big. Use a long,
* paranoid delay value and hope for the best... */
end = current;
mono_time_add_usecs(&end, USECS_PER_SEC);
}
while (mono_time_before(¤t, &end))
timer_monotonic_get(¤t);
}
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