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kernel/linux-imx6_3.14.28/arch/avr32/lib/delay.c 1.27 KB
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  /*
   *      Precise Delay Loops for avr32
   *
   *      Copyright (C) 1993 Linus Torvalds
   *      Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
   *	Copyright (C) 2005-2006 Atmel Corporation
   *
   * 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/delay.h>
  #include <linux/module.h>
  #include <linux/timex.h>
  #include <linux/param.h>
  #include <linux/types.h>
  #include <linux/init.h>
  
  #include <asm/processor.h>
  #include <asm/sysreg.h>
  
  int read_current_timer(unsigned long *timer_value)
  {
  	*timer_value = sysreg_read(COUNT);
  	return 0;
  }
  
  void __delay(unsigned long loops)
  {
  	unsigned bclock, now;
  
  	bclock = sysreg_read(COUNT);
  	do {
  		now = sysreg_read(COUNT);
  	} while ((now - bclock) < loops);
  }
  
  inline void __const_udelay(unsigned long xloops)
  {
  	unsigned long long loops;
  
  	asm("mulu.d %0, %1, %2"
  	    : "=r"(loops)
  	    : "r"(current_cpu_data.loops_per_jiffy * HZ), "r"(xloops));
  	__delay(loops >> 32);
  }
  
  void __udelay(unsigned long usecs)
  {
  	__const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
  }
  
  void __ndelay(unsigned long nsecs)
  {
  	__const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
  }