// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 1993, 2000 Linus Torvalds * * Delay routines, using a pre-computed "loops_per_jiffy" value. */ #include <linux/module.h> #include <linux/sched.h> /* for udelay's use of smp_processor_id */ #include <asm/param.h> #include <asm/smp.h> #include <linux/delay.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) { int tmp; __asm__ __volatile__( " rpcc %0\n" " addl %1,%0,%1\n" "1: rpcc %0\n" " subl %1,%0,%0\n" " bgt %0,1b" : "=&r" (tmp), "=r" (loops) : "1"(loops)); } EXPORT_SYMBOL(__delay); #ifdef CONFIG_SMP #define LPJ cpu_data[smp_processor_id()].loops_per_jiffy #else #define LPJ loops_per_jiffy #endif void udelay(unsigned long usecs) { usecs *= (((unsigned long)HZ << 32) / 1000000) * LPJ; __delay((long)usecs >> 32); } EXPORT_SYMBOL(udelay); void ndelay(unsigned long nsecs) { nsecs *= (((unsigned long)HZ << 32) / 1000000000) * LPJ; __delay((long)nsecs >> 32); } EXPORT_SYMBOL(ndelay);