text: /*
   * include/asm-microblaze/delay.h
   *
   * This file is subject to the terms and conditions of the GNU General Public
   * License. See the file "COPYING" in the main directory of this archive
   * for more details.
   *
   * Copyright (C) 2008 Michal Simek
   * Copyright (C) 2007 John Williams
   * Copyright (C) 2006 Atmark Techno, Inc.
   */
  
  #ifndef _ASM_MICROBLAZE_DELAY_H
  #define _ASM_MICROBLAZE_DELAY_H
  
  #include <linux/param.h>
  
  extern inline void __delay(unsigned long loops)
  {
  	asm volatile ("# __delay		\n\t"		\
  			"1: addi	%0, %0, -1\t\n"		\
  			"bneid	%0, 1b		\t\n"		\
  			"nop			\t\n"
  			: "=r" (loops)
  			: "0" (loops));
  }
  
  /*
   * Note that 19 * 226 == 4294 ==~ 2^32 / 10^6, so
   * loops = (4294 * usecs * loops_per_jiffy * HZ) / 2^32.
   *
   * The mul instruction gives us loops = (a * b) / 2^32.
   * We choose a = usecs * 19 * HZ and b = loops_per_jiffy * 226
   * because this lets us support a wide range of HZ and
   * loops_per_jiffy values without either a or b overflowing 2^32.
   * Thus we need usecs * HZ <= (2^32 - 1) / 19 = 226050910 and
   * loops_per_jiffy <= (2^32 - 1) / 226 = 19004280
   * (which corresponds to ~3800 bogomips at HZ = 100).
   * -- paulus
   */
  #define __MAX_UDELAY	(226050910UL/HZ)	/* maximum udelay argument */
  #define __MAX_NDELAY	(4294967295UL/HZ)	/* maximum ndelay argument */
  
  extern unsigned long loops_per_jiffy;
  
  extern inline void __udelay(unsigned int x)
  {
  
  	unsigned long long tmp =
  		(unsigned long long)x * (unsigned long long)loops_per_jiffy \
  			* 226LL;
  	unsigned loops = tmp >> 32;
  
  /*
  	__asm__("mulxuu %0,%1,%2" : "=r" (loops) :
  		"r" (x), "r" (loops_per_jiffy * 226));
  */
  	__delay(loops);
  }
  
  extern void __bad_udelay(void);		/* deliberately undefined */
  extern void __bad_ndelay(void);		/* deliberately undefined */
  
  #define udelay(n) (__builtin_constant_p(n) ? \
  	((n) > __MAX_UDELAY ? __bad_udelay() : __udelay((n) * (19 * HZ))) : \
  	__udelay((n) * (19 * HZ)))
  
  #define ndelay(n) (__builtin_constant_p(n) ? \
  	((n) > __MAX_NDELAY ? __bad_ndelay() : __udelay((n) * HZ)) : \
  	__udelay((n) * HZ))
  
  #define muldiv(a, b, c)		(((a)*(b))/(c))
  
  #endif /* _ASM_MICROBLAZE_DELAY_H */
  