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/*
* (C) Copyright 2000, 2001
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* 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>
#ifndef CONFIG_WD_PERIOD
# define CONFIG_WD_PERIOD (10 * 1000 * 1000) /* 10 seconds default*/
#endif
/* ------------------------------------------------------------------------- */
/*
* This function is intended for SHORT delays only.
* It will overflow at around 10 seconds @ 400MHz,
* or 20 seconds @ 200MHz.
*/
unsigned long usec2ticks(unsigned long usec)
{
ulong ticks;
if (usec < 1000) {
ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000;
} else {
ticks = ((usec / 10) * (get_tbclk() / 100000));
}
return (ticks);
}
/* ------------------------------------------------------------------------- */
/*
* We implement the delay by converting the delay (the number of
* microseconds to wait) into a number of time base ticks; then we
* watch the time base until it has incremented by that amount.
*/
void udelay(unsigned long usec)
{
ulong ticks, kv;
do {
kv = usec > CONFIG_WD_PERIOD ? CONFIG_WD_PERIOD : usec;
ticks = usec2ticks (kv);
wait_ticks (ticks);
usec -= kv;
} while(usec);
}
/* ------------------------------------------------------------------------- */
unsigned long ticks2usec(unsigned long ticks)
{
ulong tbclk = get_tbclk();
/* usec = ticks * 1000000 / tbclk
* Multiplication would overflow at ~4.2e3 ticks,
* so we break it up into
* usec = ( ( ticks * 1000) / tbclk ) * 1000;
*/
ticks *= 1000L;
ticks /= tbclk;
ticks *= 1000L;
return ((ulong)ticks);
}
/* ------------------------------------------------------------------------- */
int init_timebase (void)
{
#if defined(CONFIG_5xx) || defined(CONFIG_8xx)
volatile immap_t *immap = (immap_t *) CFG_IMMR;
/* unlock */
immap->im_sitk.sitk_tbk = KAPWR_KEY;
#endif
/* reset */
asm ("li 3,0 ; mttbu 3 ; mttbl 3 ;");
#if defined(CONFIG_5xx) || defined(CONFIG_8xx)
/* enable */
immap->im_sit.sit_tbscr |= TBSCR_TBE;
#endif
return (0);
}
/* ------------------------------------------------------------------------- */
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