linux/arch/mn10300/lib/delay.c

52 lines
1.1 KiB
C

/* MN10300 Short delay interpolation routines
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* 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);