u-boot/arch/arm/cpu/s3c44b0/timer.c

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/*
* (C) Copyright 2004
* DAVE Srl
* http://www.dave-tech.it
* http://www.wawnet.biz
* mailto:info@wawnet.biz
*
* See file CREDITS for list of people who contributed to this
* project.
*
* 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <asm/hardware.h>
/* we always count down the max. */
#define TIMER_LOAD_VAL 0xffff
/* macro to read the 16 bit timer */
#define READ_TIMER (TCNTO1 & 0xffff)
#ifdef CONFIG_USE_IRQ
#error CONFIG_USE_IRQ NOT supported
#endif
static ulong timestamp;
static ulong lastdec;
int timer_init (void)
{
TCFG0 = 0x000000E9;
TCFG1 = 0x00000004;
TCON = 0x00000900;
TCNTB1 = TIMER_LOAD_VAL;
TCMPB1 = 0;
TCON = 0x00000B00;
TCON = 0x00000900;
lastdec = TCNTB1 = TIMER_LOAD_VAL;
timestamp = 0;
return 0;
}
/*
* timer without interrupts
*/
ulong get_timer (ulong base)
{
return get_timer_masked () - base;
}
void __udelay (unsigned long usec)
{
ulong tmo;
tmo = usec / 1000;
tmo *= CONFIG_SYS_HZ;
tmo /= 8;
tmo += get_timer (0);
while (get_timer_masked () < tmo)
/*NOP*/;
}
ulong get_timer_masked (void)
{
ulong now = READ_TIMER;
if (lastdec >= now) {
/* normal mode */
timestamp += lastdec - now;
} else {
/* we have an overflow ... */
timestamp += lastdec + TIMER_LOAD_VAL - now;
}
lastdec = now;
return timestamp;
}
void udelay_masked (unsigned long usec)
{
ulong tmo;
ulong endtime;
signed long diff;
if (usec >= 1000) {
tmo = usec / 1000;
tmo *= CONFIG_SYS_HZ;
tmo /= 8;
} else {
tmo = usec * CONFIG_SYS_HZ;
tmo /= (1000*8);
}
endtime = get_timer(0) + tmo;
do {
ulong now = get_timer_masked ();
diff = endtime - now;
} while (diff >= 0);
}