u-boot/arch/mips/lib/time.c

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/*
* (C) Copyright 2003
* 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>
#include <asm/mipsregs.h>
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static unsigned long timestamp;
/* how many counter cycles in a jiffy */
#define CYCLES_PER_JIFFY (CONFIG_SYS_MIPS_TIMER_FREQ + CONFIG_SYS_HZ / 2) / CONFIG_SYS_HZ
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/*
* timer without interrupts
*/
int timer_init(void)
{
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/* Set up the timer for the first expiration. */
timestamp = 0;
write_c0_compare(read_c0_count() + CYCLES_PER_JIFFY);
return 0;
}
void reset_timer(void)
{
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timestamp = 0;
write_c0_compare(read_c0_count() + CYCLES_PER_JIFFY);
}
ulong get_timer(ulong base)
{
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unsigned int count;
unsigned int expirelo = read_c0_compare();
/* Check to see if we have missed any timestamps. */
count = read_c0_count();
while ((count - expirelo) < 0x7fffffff) {
expirelo += CYCLES_PER_JIFFY;
timestamp++;
}
write_c0_compare(expirelo);
return (timestamp - base);
}
void set_timer(ulong t)
{
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timestamp = t;
write_c0_compare(read_c0_count() + CYCLES_PER_JIFFY);
}
void __udelay(unsigned long usec)
{
unsigned int tmo;
tmo = read_c0_count() + (usec * (CONFIG_SYS_MIPS_TIMER_FREQ / 1000000));
while ((tmo - read_c0_count()) < 0x7fffffff)
/*NOP*/;
}
/*
* This function is derived from PowerPC code (read timebase as long long).
* On MIPS it just returns the timer value.
*/
unsigned long long get_ticks(void)
{
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return get_timer(0);
}
/*
* This function is derived from PowerPC code (timebase clock frequency).
* On MIPS it returns the number of timer ticks per second.
*/
ulong get_tbclk(void)
{
return CONFIG_SYS_HZ;
}