LXR linux/arch/sh/lib64/udelay.c

   1/*
   2 * arch/sh/lib64/udelay.c
   3 *
   4 * Delay routines, using a pre-computed "loops_per_jiffy" value.
   5 *
   6 * Copyright (C) 2000, 2001  Paolo Alberelli
   7 * Copyright (C) 2003, 2004  Paul Mundt
   8 *
   9 * This file is subject to the terms and conditions of the GNU General Public
  10 * License.  See the file "COPYING" in the main directory of this archive
  11 * for more details.
  12 */
  13#include <linux/sched.h>
  14#include <asm/param.h>
  15
  16/*
  17 * Use only for very small delays (< 1 msec).
  18 *
  19 * The active part of our cycle counter is only 32-bits wide, and
  20 * we're treating the difference between two marks as signed.  On
  21 * a 1GHz box, that's about 2 seconds.
  22 */
  23
  24void __delay(unsigned long loops)
  25{
  26        long long dummy;
  27        __asm__ __volatile__("gettr     tr0, %1\n\t"
  28                             "pta       $+4, tr0\n\t"
  29                             "addi      %0, -1, %0\n\t"
  30                             "bne       %0, r63, tr0\n\t"
  31                             "ptabs     %1, tr0\n\t":"=r"(loops),
  32                             "=r"(dummy)
  33                             :"0"(loops));
  34}
  35
  36void __const_udelay(unsigned long xloops)
  37{
  38        __delay(xloops * (HZ * cpu_data[raw_smp_processor_id()].loops_per_jiffy));
  39}
  40
  41void __udelay(unsigned long usecs)
  42{
  43        __const_udelay(usecs * 0x000010c6);  /* 2**32 / 1000000 */
  44}
  45
  46void __ndelay(unsigned long nsecs)
  47{
  48        __const_udelay(nsecs * 0x00000005);
  49}
  50