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/*
* include/asm-xtensa/delay.h
*
* 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) 2001 - 2005 Tensilica Inc.
*
*/
#ifndef _XTENSA_DELAY_H
#define _XTENSA_DELAY_H
#include <asm/timex.h>
#include <asm/param.h>
extern unsigned long loops_per_jiffy;
static inline void __delay(unsigned long loops)
{
if (__builtin_constant_p(loops) && loops < 2)
__asm__ __volatile__ ("nop");
else if (loops >= 2)
/* 2 cycles per loop. */
__asm__ __volatile__ ("1: addi %0, %0, -2; bgeui %0, 2, 1b"
: "+r" (loops));
}
/* Undefined function to get compile-time error */
void __bad_udelay(void);
void __bad_ndelay(void);
#define __MAX_UDELAY 30000
#define __MAX_NDELAY 30000
static inline void __udelay(unsigned long usecs)
{
unsigned long start = get_ccount();
unsigned long cycles = (usecs * (ccount_freq >> 15)) >> 5;
/* Note: all variables are unsigned (can wrap around)! */
while (((unsigned long)get_ccount()) - start < cycles)
cpu_relax();
}
static inline void udelay(unsigned long usec)
{
if (__builtin_constant_p(usec) && usec >= __MAX_UDELAY)
__bad_udelay();
else
__udelay(usec);
}
static inline void __ndelay(unsigned long nsec)
{
/*
* Inner shift makes sure multiplication doesn't overflow
* for legitimate nsec values
*/
unsigned long cycles = (nsec * (ccount_freq >> 15)) >> 15;
__delay(cycles);
}
#define ndelay(n) ndelay(n)
static inline void ndelay(unsigned long nsec)
{
if (__builtin_constant_p(nsec) && nsec >= __MAX_NDELAY)
__bad_ndelay();
else
__ndelay(nsec);
}
#endif
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