delay.c

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/* MN10300 Short delay interpolation routines
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <asm/div64.h>

/*
 * basic delay loop
 */
void __delay(unsigned long loops)
{
    int d0;

    asm volatile(
        "   bra 1f  \n"
        "   .align  4   \n"
        "1: bra 2f  \n"
        "   .align  4   \n"
        "2: add -1,%0   \n"
        "   bne 2b  \n"
        : "=&d" (d0)
        : "0" (loops)
        : "cc");
}
EXPORT_SYMBOL(__delay);

/*
 * handle a delay specified in terms of microseconds
 */
void __udelay(unsigned long usecs)
{
    unsigned long start, stop, cnt;

    /* usecs * CLK / 1E6 */
    stop = __muldiv64u(usecs, MN10300_TSCCLK, 1000000);
    start = TMTSCBC;

    do {
        cnt = start - TMTSCBC;
    } while (cnt < stop);
}
EXPORT_SYMBOL(__udelay);