time.c 1.38 KB
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/*
 * (C) Copyright 2003
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
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 * SPDX-License-Identifier:	GPL-2.0+
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 */

#include <common.h>
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#include <asm/mipsregs.h>
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static unsigned long timestamp;

/* how many counter cycles in a jiffy */
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#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. */
	write_c0_compare(read_c0_count() + CYCLES_PER_JIFFY);
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	return 0;
}

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);

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	return timestamp - base;
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}

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void __udelay(unsigned long usec)
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{
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	unsigned int tmo;
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	tmo = read_c0_count() + (usec * (CONFIG_SYS_MIPS_TIMER_FREQ / 1000000));
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	while ((tmo - read_c0_count()) < 0x7fffffff)
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		/*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);
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}

/*
 * 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)
{
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	return CONFIG_SYS_HZ;
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}