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

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
   4 * Mostly copied from arch/x86/lib/delay.c
   5 */
   6
   7#include <linux/export.h>
   8#include <linux/kernel.h>
   9#include <linux/delay.h>
  10#include <asm/param.h>
  11
  12void __delay(unsigned long loops)
  13{
  14        asm volatile(
  15                "test %0,%0\n"
  16                "jz 3f\n"
  17                "jmp 1f\n"
  18
  19                ".align 16\n"
  20                "1: jmp 2f\n"
  21
  22                ".align 16\n"
  23                "2: dec %0\n"
  24                " jnz 2b\n"
  25                "3: dec %0\n"
  26
  27                : /* we don't need output */
  28                : "a" (loops)
  29        );
  30}
  31EXPORT_SYMBOL(__delay);
  32
  33inline void __const_udelay(unsigned long xloops)
  34{
  35        int d0;
  36
  37        xloops *= 4;
  38        asm("mull %%edx"
  39                : "=d" (xloops), "=&a" (d0)
  40                : "1" (xloops), "0"
  41                (loops_per_jiffy * (HZ/4)));
  42
  43        __delay(++xloops);
  44}
  45EXPORT_SYMBOL(__const_udelay);
  46
  47void __udelay(unsigned long usecs)
  48{
  49        __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
  50}
  51EXPORT_SYMBOL(__udelay);
  52
  53void __ndelay(unsigned long nsecs)
  54{
  55        __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
  56}
  57EXPORT_SYMBOL(__ndelay);
  58