u-boot/arch/arm/cpu/armv7/socfpga/timer.c

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/*
* Copyright (C) 2012 Altera Corporation <www.altera.com>
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include <common.h>
#include <asm/io.h>
#include <asm/arch/timer.h>
DECLARE_GLOBAL_DATA_PTR;
static const struct socfpga_timer *timer_base = (void *)CONFIG_SYS_TIMERBASE;
/*
* Timer initialization
*/
int timer_init(void)
{
writel(TIMER_LOAD_VAL, &timer_base->load_val);
writel(TIMER_LOAD_VAL, &timer_base->curr_val);
writel(readl(&timer_base->ctrl) | 0x3, &timer_base->ctrl);
return 0;
}
static u32 read_timer(void)
{
return readl(&timer_base->curr_val);
}
/*
* Delay x useconds
*/
void __udelay(unsigned long usec)
{
unsigned long now, last;
/*
* get the tmo value based on timer clock speed
* tmo = delay required / period of timer clock
*/
long tmo = usec * CONFIG_TIMER_CLOCK_KHZ / 1000;
last = read_timer();
while (tmo > 0) {
now = read_timer();
if (last >= now)
/* normal mode (non roll) */
tmo -= last - now;
else
/* we have overflow of the count down timer */
tmo -= TIMER_LOAD_VAL - last + now;
last = now;
}
}
/*
* Get the timer value
*/
ulong get_timer(ulong base)
{
return get_timer_masked() - base;
}
/*
* Timer : get the time difference
* Unit of tick is based on the CONFIG_SYS_HZ
*/
ulong get_timer_masked(void)
{
/* current tick value */
ulong now = read_timer() / (CONFIG_TIMER_CLOCK_KHZ/CONFIG_SYS_HZ);
if (gd->lastinc >= now) {
/* normal mode (non roll) */
/* move stamp forward with absolute diff ticks */
gd->tbl += gd->lastinc - now;
} else {
/* we have overflow of the count down timer */
gd->tbl += TIMER_LOAD_VAL - gd->lastinc + now;
}
gd->lastinc = now;
return gd->tbl;
}
/*
* Reset the timer
*/
void reset_timer(void)
{
/* capture current decrementer value time */
gd->lastinc = read_timer() / (CONFIG_TIMER_CLOCK_KHZ/CONFIG_SYS_HZ);
/* start "advancing" time stamp from 0 */
gd->tbl = 0;
}