include/asm-cris/delay.h

   1 #ifndef _CRIS_DELAY_H
   2 #define _CRIS_DELAY_H
   3
   4 /*
   5  * Copyright (C) 1998, 1999, 2000, 2001 Axis Communications AB
   6  *
   7  * Delay routines, using a pre-computed "loops_per_second" value.
   8  */
   9
  10 #include <linux/config.h>
  11 #include <linux/linkage.h>
  12
  13 #ifdef CONFIG_SMP
  14 #include <asm/smp.h>
  15 #endif
  16
  17 extern void __do_delay(void);   /* Special register call calling convention */
  18
  19 extern __inline__ void __delay(int loops)
  20 {
  21         __asm__ __volatile__ (
  22                               "move.d %0,$r9\n\t"
  23                               "beq 2f\n\t"
  24                               "subq 1,$r9\n\t"
  25                               "1:\n\t"
  26                               "bne 1b\n\t"
  27                               "subq 1,$r9\n"
  28                               "2:"
  29                               : : "g" (loops) : "r9");
  30 }
  31
  32
  33 /* Use only for very small delays ( < 1 msec).  */
  34
  35 extern unsigned long loops_per_usec; /* arch/cris/mm/init.c */
  36
  37 extern __inline__ void udelay(unsigned long usecs)
  38 {
  39         __delay(usecs * loops_per_usec);
  40 }
  41
  42 /* ETRAX 100 is really too slow to sleep for nanosecs. */
  43 /* Divide with 1024 to avoid a real division that would take >1 us... */
  44 extern __inline__ void ndelay(unsigned long nsecs)
  45 {
  46         __delay(1 + nsecs * loops_per_usec / 1024);
  47 }
  48
  49 #endif /* defined(_CRIS_DELAY_H) */
  50
  51
  52