original_kernel/arch/sh/lib64/udelay.c

/*
 * arch/sh/lib64/udelay.c
 *
 * Delay routines, using a pre-computed "loops_per_jiffy" value.
 *
 * Copyright (C) 2000, 2001  Paolo Alberelli
 * Copyright (C) 2003, 2004  Paul Mundt
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/sched.h>
#include <asm/param.h>

/*
 * Use only for very small delays (< 1 msec).
 *
 * The active part of our cycle counter is only 32-bits wide, and
 * we're treating the difference between two marks as signed.  On
 * a 1GHz box, that's about 2 seconds.
 */

void __delay(int loops)
{
	long long dummy;
	__asm__ __volatile__("gettr	tr0, %1\n\t"
			     "pta	$+4, tr0\n\t"
			     "addi	%0, -1, %0\n\t"
			     "bne	%0, r63, tr0\n\t"
			     "ptabs	%1, tr0\n\t":"=r"(loops),
			     "=r"(dummy)
			     :"0"(loops));
}

void __udelay(unsigned long long usecs, unsigned long lpj)
{
	usecs *= (((unsigned long long) HZ << 32) / 1000000) * lpj;
	__delay((long long) usecs >> 32);
}

void __ndelay(unsigned long long nsecs, unsigned long lpj)
{
	nsecs *= (((unsigned long long) HZ << 32) / 1000000000) * lpj;
	__delay((long long) nsecs >> 32);
}

void udelay(unsigned long usecs)
{
	__udelay(usecs, cpu_data[raw_smp_processor_id()].loops_per_jiffy);
}

void ndelay(unsigned long nsecs)
{
	__ndelay(nsecs, cpu_data[raw_smp_processor_id()].loops_per_jiffy);
}