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kernel/linux-imx6_3.14.28/arch/mn10300/lib/delay.c 1.06 KB
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  /* MN10300 Short delay interpolation routines
   *
   * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   * Written by David Howells (dhowells@redhat.com)
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public Licence
   * as published by the Free Software Foundation; either version
   * 2 of the Licence, or (at your option) any later version.
   */
  #include <linux/module.h>
  #include <linux/sched.h>
  #include <linux/delay.h>
  #include <asm/div64.h>
  
  /*
   * basic delay loop
   */
  void __delay(unsigned long loops)
  {
  	int d0;
  
  	asm volatile(
  		"	bra	1f	
  "
  		"	.align	4	
  "
  		"1:	bra	2f	
  "
  		"	.align	4	
  "
  		"2:	add	-1,%0	
  "
  		"	bne	2b	
  "
  		: "=&d" (d0)
  		: "0" (loops)
  		: "cc");
  }
  EXPORT_SYMBOL(__delay);
  
  /*
   * handle a delay specified in terms of microseconds
   */
  void __udelay(unsigned long usecs)
  {
  	unsigned long start, stop, cnt;
  
  	/* usecs * CLK / 1E6 */
  	stop = __muldiv64u(usecs, MN10300_TSCCLK, 1000000);
  	start = TMTSCBC;
  
  	do {
  		cnt = start - TMTSCBC;
  	} while (cnt < stop);
  }
  EXPORT_SYMBOL(__udelay);