LXR linux/arch/parisc/include/asm/delay.h

   1#ifndef _PARISC_DELAY_H
   2#define _PARISC_DELAY_H
   3
   4#include <asm/special_insns.h>    /* for mfctl() */
   5#include <asm/processor.h> /* for boot_cpu_data */
   6
   7
   8/*
   9 * Copyright (C) 1993 Linus Torvalds
  10 *
  11 * Delay routines
  12 */
  13
  14static __inline__ void __delay(unsigned long loops) {
  15        asm volatile(
  16        "       .balignl        64,0x34000034\n"
  17        "       addib,UV -1,%0,.\n"
  18        "       nop\n"
  19                : "=r" (loops) : "0" (loops));
  20}
  21
  22static __inline__ void __cr16_delay(unsigned long clocks) {
  23        unsigned long start;
  24
  25        /*
  26         * Note: Due to unsigned math, cr16 rollovers shouldn't be
  27         * a problem here. However, on 32 bit, we need to make sure
  28         * we don't pass in too big a value. The current default
  29         * value of MAX_UDELAY_MS should help prevent this.
  30         */
  31
  32        start = mfctl(16);
  33        while ((mfctl(16) - start) < clocks)
  34            ;
  35}
  36
  37static __inline__ void __udelay(unsigned long usecs) {
  38        __cr16_delay(usecs * ((unsigned long)boot_cpu_data.cpu_hz / 1000000UL));
  39}
  40
  41#define udelay(n) __udelay(n)
  42
  43#endif /* defined(_PARISC_DELAY_H) */
  44