u-boot/arch/arm/cpu/arm920t/a320/timer.c
2011-07-26 14:53:30 +02:00

164 lines
3.9 KiB
C

/*
* (C) Copyright 2009 Faraday Technology
* Po-Yu Chuang <ratbert@faraday-tech.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, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <common.h>
#include <asm/io.h>
#include <faraday/ftpmu010.h>
#include <faraday/fttmr010.h>
static ulong timestamp;
static ulong lastdec;
static struct fttmr010 *tmr = (struct fttmr010 *)CONFIG_FTTMR010_BASE;
#define TIMER_CLOCK 32768
#define TIMER_LOAD_VAL 0xffffffff
int timer_init(void)
{
unsigned int cr;
debug("%s()\n", __func__);
/* disable timers */
writel(0, &tmr->cr);
/* use 32768Hz oscillator for RTC, WDT, TIMER */
ftpmu010_32768osc_enable();
/* setup timer */
writel(TIMER_LOAD_VAL, &tmr->timer3_load);
writel(TIMER_LOAD_VAL, &tmr->timer3_counter);
writel(0, &tmr->timer3_match1);
writel(0, &tmr->timer3_match2);
/* we don't want timer to issue interrupts */
writel(FTTMR010_TM3_MATCH1 |
FTTMR010_TM3_MATCH2 |
FTTMR010_TM3_OVERFLOW,
&tmr->interrupt_mask);
cr = readl(&tmr->cr);
cr |= FTTMR010_TM3_CLOCK; /* use external clock */
cr |= FTTMR010_TM3_ENABLE;
writel(cr, &tmr->cr);
/* init the timestamp and lastdec value */
reset_timer_masked();
return 0;
}
/*
* timer without interrupts
*/
/*
* reset time
*/
void reset_timer_masked(void)
{
/* capure current decrementer value time */
lastdec = readl(&tmr->timer3_counter) / (TIMER_CLOCK / CONFIG_SYS_HZ);
timestamp = 0; /* start "advancing" time stamp from 0 */
debug("%s(): lastdec = %lx\n", __func__, lastdec);
}
/*
* return timer ticks
*/
ulong get_timer_masked(void)
{
/* current tick value */
ulong now = readl(&tmr->timer3_counter) / (TIMER_CLOCK / CONFIG_SYS_HZ);
debug("%s(): now = %lx, lastdec = %lx\n", __func__, now, lastdec);
if (lastdec >= now) {
/*
* normal mode (non roll)
* move stamp fordward with absoulte diff ticks
*/
timestamp += lastdec - now;
} else {
/*
* we have overflow of the count down timer
*
* nts = ts + ld + (TLV - now)
* ts=old stamp, ld=time that passed before passing through -1
* (TLV-now) amount of time after passing though -1
* nts = new "advancing time stamp"...it could also roll and
* cause problems.
*/
timestamp += lastdec + TIMER_LOAD_VAL - now;
}
lastdec = now;
debug("%s() returns %lx\n", __func__, timestamp);
return timestamp;
}
/*
* return difference between timer ticks and base
*/
ulong get_timer(ulong base)
{
debug("%s(%lx)\n", __func__, base);
return get_timer_masked() - base;
}
/* delay x useconds AND preserve advance timestamp value */
void __udelay(unsigned long usec)
{
long tmo = usec * (TIMER_CLOCK / 1000) / 1000;
unsigned long now, last = readl(&tmr->timer3_counter);
debug("%s(%lu)\n", __func__, usec);
while (tmo > 0) {
now = readl(&tmr->timer3_counter);
if (now > last) /* count down timer overflow */
tmo -= TIMER_LOAD_VAL + last - now;
else
tmo -= last - now;
last = now;
}
}
/*
* This function is derived from PowerPC code (read timebase as long long).
* On ARM it just returns the timer value.
*/
unsigned long long get_ticks(void)
{
debug("%s()\n", __func__);
return get_timer(0);
}
/*
* This function is derived from PowerPC code (timebase clock frequency).
* On ARM it returns the number of timer ticks per second.
*/
ulong get_tbclk(void)
{
debug("%s()\n", __func__);
return CONFIG_SYS_HZ;
}