linux/arch/blackfin/include/asm/delay.h
Barry Song 6388d14eb2 Blackfin: implement ndelay()
Signed-off-by: Barry Song <barry.song@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2010-03-09 00:30:50 -05:00

51 lines
917 B
C

/*
* delay.h - delay functions
*
* Copyright (c) 2004-2007 Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*/
#ifndef __ASM_DELAY_H__
#define __ASM_DELAY_H__
#include <mach/anomaly.h>
static inline void __delay(unsigned long loops)
{
__asm__ __volatile__ (
"LSETUP(1f, 1f) LC0 = %0;"
"1: NOP;"
:
: "a" (loops)
: "LT0", "LB0", "LC0"
);
}
#include <linux/param.h> /* needed for HZ */
/*
* close approximation borrowed from m68knommu to avoid 64-bit math
*/
#define HZSCALE (268435456 / (1000000/HZ))
static inline unsigned long __to_delay(unsigned long scale)
{
extern unsigned long loops_per_jiffy;
return (((scale * HZSCALE) >> 11) * (loops_per_jiffy >> 11)) >> 6;
}
static inline void udelay(unsigned long usecs)
{
__delay(__to_delay(usecs));
}
static inline void ndelay(unsigned long nsecs)
{
__delay(__to_delay(1) * nsecs / 1000);
}
#define ndelay ndelay
#endif