sys/arch/bebox/stand/boot/clock.c

   1 /*      $NetBSD: clock.c,v 1.11 2008/05/26 16:28:39 kiyohara Exp $      */
   2
   3 /*
   4  * Copyright (C) 1995, 1996 Wolfgang Solfrank.
   5  * Copyright (C) 1995, 1996 TooLs GmbH.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by TooLs GmbH.
  19  * 4. The name of TooLs GmbH may not be used to endorse or promote products
  20  *    derived from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
  23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  25  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  26  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  27  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  28  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  29  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  30  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  31  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <lib/libsa/stand.h>
  35 #include <sys/param.h>
  36 #include <dev/isa/isareg.h>
  37 #include <dev/ic/i8253reg.h>
  38 #include "boot.h"
  39
  40 static inline u_quad_t mftb(void);
  41
  42 static inline u_quad_t
  43 mftb(void)
  44 {
  45         u_long scratch;
  46         u_quad_t tb;
  47
  48         __asm ("1: mftbu %0; mftb %0+1; mftbu %1; cmpw %0,%1; bne 1b"
  49             : "=r"(tb), "=r"(scratch));
  50         return (tb);
  51 }
  52
  53 /*
  54  * Wait for about n microseconds (at least!).
  55  */
  56 void
  57 delay(u_int n)
  58 {
  59         u_quad_t tb;
  60         u_long tbh, tbl, scratch;
  61
  62         tb = mftb();
  63         tb += (n * 1000 + NS_PER_TICK - 1) / NS_PER_TICK;
  64         tbh = tb >> 32;
  65         tbl = tb;
  66         __asm ("1: mftbu %0; cmpw %0,%1; blt 1b; bgt 2f;"
  67              "mftb %0; cmpw 0, %0,%2; blt 1b; 2:"
  68              : "=&r"(scratch) : "r"(tbh), "r"(tbl));
  69 }