delay.c
1.27 KB
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/*
* Precise Delay Loops for avr32
*
* Copyright (C) 1993 Linus Torvalds
* Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
* Copyright (C) 2005-2006 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/timex.h>
#include <linux/param.h>
#include <linux/types.h>
#include <linux/init.h>
#include <asm/processor.h>
#include <asm/sysreg.h>
int read_current_timer(unsigned long *timer_value)
{
*timer_value = sysreg_read(COUNT);
return 0;
}
void __delay(unsigned long loops)
{
unsigned bclock, now;
bclock = sysreg_read(COUNT);
do {
now = sysreg_read(COUNT);
} while ((now - bclock) < loops);
}
inline void __const_udelay(unsigned long xloops)
{
unsigned long long loops;
asm("mulu.d %0, %1, %2"
: "=r"(loops)
: "r"(current_cpu_data.loops_per_jiffy * HZ), "r"(xloops));
__delay(loops >> 32);
}
void __udelay(unsigned long usecs)
{
__const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
}
void __ndelay(unsigned long nsecs)
{
__const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
}