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kernel/linux-imx6_3.14.28/arch/x86/um/delay.c 1.14 KB
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  /*
   * Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
   * Mostly copied from arch/x86/lib/delay.c
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/delay.h>
  #include <asm/param.h>
  
  void __delay(unsigned long loops)
  {
  	asm volatile(
  		"test %0,%0
  "
  		"jz 3f
  "
  		"jmp 1f
  "
  
  		".align 16
  "
  		"1: jmp 2f
  "
  
  		".align 16
  "
  		"2: dec %0
  "
  		" jnz 2b
  "
  		"3: dec %0
  "
  
  		: /* we don't need output */
  		: "a" (loops)
  	);
  }
  EXPORT_SYMBOL(__delay);
  
  inline void __const_udelay(unsigned long xloops)
  {
  	int d0;
  
  	xloops *= 4;
  	asm("mull %%edx"
  		: "=d" (xloops), "=&a" (d0)
  		: "1" (xloops), "0"
  		(loops_per_jiffy * (HZ/4)));
  
  	__delay(++xloops);
  }
  EXPORT_SYMBOL(__const_udelay);
  
  void __udelay(unsigned long usecs)
  {
  	__const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
  }
  EXPORT_SYMBOL(__udelay);
  
  void __ndelay(unsigned long nsecs)
  {
  	__const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
  }
  EXPORT_SYMBOL(__ndelay);