LXR linux/arch/x86/um/delay.c

   1/*
   2 * Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
   3 * Mostly copied from arch/x86/lib/delay.c
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License version 2 as
   7 * published by the Free Software Foundation.
   8 */
   9
  10#include <linux/export.h>
  11#include <linux/kernel.h>
  12#include <linux/delay.h>
  13#include <asm/param.h>
  14
  15void __delay(unsigned long loops)
  16{
  17        asm volatile(
  18                "test %0,%0\n"
  19                "jz 3f\n"
  20                "jmp 1f\n"
  21
  22                ".align 16\n"
  23                "1: jmp 2f\n"
  24
  25                ".align 16\n"
  26                "2: dec %0\n"
  27                " jnz 2b\n"
  28                "3: dec %0\n"
  29
  30                : /* we don't need output */
  31                : "a" (loops)
  32        );
  33}
  34EXPORT_SYMBOL(__delay);
  35
  36inline void __const_udelay(unsigned long xloops)
  37{
  38        int d0;
  39
  40        xloops *= 4;
  41        asm("mull %%edx"
  42                : "=d" (xloops), "=&a" (d0)
  43                : "1" (xloops), "0"
  44                (loops_per_jiffy * (HZ/4)));
  45
  46        __delay(++xloops);
  47}
  48EXPORT_SYMBOL(__const_udelay);
  49
  50void __udelay(unsigned long usecs)
  51{
  52        __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
  53}
  54EXPORT_SYMBOL(__udelay);
  55
  56void __ndelay(unsigned long nsecs)
  57{
  58        __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
  59}
  60EXPORT_SYMBOL(__ndelay);
  61