/*      $NetBSD: clock.c,v 1.12 2009/03/18 10:22:26 cegger Exp $        */

/*
* Copyright (C) 1995, 1996 Wolfgang Solfrank.
* Copyright (C) 1995, 1996 TooLs GmbH.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*      This product includes software developed by TooLs GmbH.
* 4. The name of TooLs GmbH may not be used to endorse or promote products
*    derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <lib/libsa/stand.h>
#include <sys/param.h>
#include <dev/isa/isareg.h>
#include <dev/ic/i8253reg.h>
#include "boot.h"

static inline u_quad_t mftb(void);

static inline u_quad_t
mftb(void)
{
       u_long scratch;
       u_quad_t tb;

       __asm ("1: mftbu %0; mftb %0+1; mftbu %1; cmpw %0,%1; bne 1b"
           : "=r"(tb), "=r"(scratch));
       return (tb);
}

/*
* Wait for about n microseconds (at least!).
*/
void
delay(u_int n)
{
       u_quad_t tb;
       u_long tbh, tbl, scratch;

       tb = mftb();
       tb += (n * 1000 + NS_PER_TICK - 1) / NS_PER_TICK;
       tbh = tb >> 32;
       tbl = tb;
       __asm ("1: mftbu %0; cmpw %0,%1; blt 1b; bgt 2f;"
            "mftb %0; cmpw 0, %0,%2; blt 1b; 2:"
            : "=&r"(scratch) : "r"(tbh), "r"(tbl));
}