LXR linux/arch/blackfin/include/asm/delay.h

   1/*
   2 * delay.h - delay functions
   3 *
   4 * Copyright (c) 2004-2007 Analog Devices Inc.
   5 *
   6 * Licensed under the GPL-2 or later.
   7 */
   8
   9#ifndef __ASM_DELAY_H__
  10#define __ASM_DELAY_H__
  11
  12#include <mach/anomaly.h>
  13
  14static inline void __delay(unsigned long loops)
  15{
  16__asm__ __volatile__ (
  17                        "LSETUP(1f, 1f) LC0 = %0;"
  18                        "1: NOP;"
  19                        :
  20                        : "a" (loops)
  21                        : "LT0", "LB0", "LC0"
  22                );
  23}
  24
  25#include <linux/param.h>        /* needed for HZ */
  26
  27/*
  28 * close approximation borrowed from m68knommu to avoid 64-bit math
  29 */
  30
  31#define HZSCALE         (268435456 / (1000000/HZ))
  32
  33static inline unsigned long __to_delay(unsigned long scale)
  34{
  35        extern unsigned long loops_per_jiffy;
  36        return (((scale * HZSCALE) >> 11) * (loops_per_jiffy >> 11)) >> 6;
  37}
  38
  39static inline void udelay(unsigned long usecs)
  40{
  41        __delay(__to_delay(usecs));
  42}
  43
  44static inline void ndelay(unsigned long nsecs)
  45{
  46        __delay(__to_delay(1) * nsecs / 1000);
  47}
  48
  49#define ndelay ndelay
  50
  51#endif
  52