arch/blackfin/include/asm/delay.h

   1 /*
   2  * delay.h - delay functions
   3  *
   4  * Copyright (c) 2004-2007 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 #ifndef __ASM_DELAY_H__
  10 #define __ASM_DELAY_H__
  11
  12 #include <mach/anomaly.h>
  13
  14 static inline void __delay(unsigned long loops)
  15 {
  16 __asm__ __volatile__ (
  17                         "LSETUP(1f, 1f) LC0 = %0;"
  18                         "1: NOP;"
  19                         :
  20                         : "a" (loops)
  21                         : "LT0", "LB0", "LC0"
  22                 );
  23 }
  24
  25 #include <linux/param.h>        /* needed for HZ */
  26
  27 /*
  28  * close approximation borrowed from m68knommu to avoid 64-bit math
  29  */
  30
  31 #define HZSCALE         (268435456 / (1000000/HZ))
  32
  33 static inline unsigned long __to_delay(unsigned long scale)
  34 {
  35         extern unsigned long loops_per_jiffy;
  36         return (((scale * HZSCALE) >> 11) * (loops_per_jiffy >> 11)) >> 6;
  37 }
  38
  39 static inline void udelay(unsigned long usecs)
  40 {
  41         __delay(__to_delay(usecs));
  42 }
  43
  44 static inline void ndelay(unsigned long nsecs)
  45 {
  46         __delay(__to_delay(1) * nsecs / 1000);
  47 }
  48
  49 #define ndelay ndelay
  50
  51 #endif