include/asm-frv/delay.h

   1 /* delay.h: FRV delay code
   2  *
   3  * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #ifndef _ASM_DELAY_H
  13 #define _ASM_DELAY_H
  14
  15 #include <asm/param.h>
  16 #include <asm/timer-regs.h>
  17
  18 /*
  19  * delay loop - runs at __core_clock_speed_HZ / 2 [there are 2 insns in the loop]
  20  */
  21 extern unsigned long __delay_loops_MHz;
  22
  23 static inline void __delay(unsigned long loops)
  24 {
  25         asm volatile("1:        subicc  %0,#1,%0,icc0   \n"
  26                      "          bnc     icc0,#2,1b      \n"
  27                      : "=r" (loops)
  28                      : "0" (loops)
  29                      : "icc0"
  30                      );
  31 }
  32
  33 /*
  34  * Use only for very small delays ( < 1 msec).  Should probably use a
  35  * lookup table, really, as the multiplications take much too long with
  36  * short delays.  This is a "reasonable" implementation, though (and the
  37  * first constant multiplications gets optimized away if the delay is
  38  * a constant)
  39  */
  40
  41 extern unsigned long loops_per_jiffy;
  42
  43 static inline void udelay(unsigned long usecs)
  44 {
  45         __delay(usecs * __delay_loops_MHz);
  46 }
  47
  48 #define ndelay(n)       udelay((n) * 5)
  49
  50 #endif /* _ASM_DELAY_H */