delay.c
1.48 KB
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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1994 by Waldorf Electronics
* Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
* Copyright (C) 2007 Maciej W. Rozycki
*/
#include <linux/module.h>
#include <linux/param.h>
#include <linux/smp.h>
#include <asm/compiler.h>
#include <asm/war.h>
void __delay(unsigned long loops)
{
__asm__ __volatile__ (
" .set noreorder \n"
" .align 3 \n"
"1: bnez %0, 1b \n"
#if BITS_PER_LONG == 32
" subu %0, 1 \n"
#else
" dsubu %0, 1 \n"
#endif
" .set reorder \n"
: "=r" (loops)
: "0" (loops));
}
EXPORT_SYMBOL(__delay);
/*
* Division by multiplication: you don't have to worry about
* loss of precision.
*
* Use only for very small delays ( < 1 msec). Should probably use a
* lookup table, really, as the multiplications take much too long with
* short delays. This is a "reasonable" implementation, though (and the
* first constant multiplications gets optimized away if the delay is
* a constant)
*/
void __udelay(unsigned long us)
{
unsigned int lpj = raw_current_cpu_data.udelay_val;
__delay((us * 0x000010c7ull * HZ * lpj) >> 32);
}
EXPORT_SYMBOL(__udelay);
void __ndelay(unsigned long ns)
{
unsigned int lpj = raw_current_cpu_data.udelay_val;
__delay((ns * 0x00000005ull * HZ * lpj) >> 32);
}
EXPORT_SYMBOL(__ndelay);