1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * OpenRISC Linux 4 * 5 * Linux architectural port borrowing liberally from similar works of 6 * others. All original copyrights apply as per the original source 7 * declaration. 8 * 9 * Modifications for the OpenRISC architecture: 10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> 11 * 12 * Precise Delay Loops 13 */ 14 15#include <linux/kernel.h> 16#include <linux/export.h> 17#include <linux/init.h> 18#include <asm/param.h> 19#include <asm/delay.h> 20#include <asm/timex.h> 21#include <asm/processor.h> 22 23int read_current_timer(unsigned long *timer_value) 24{ 25 *timer_value = get_cycles(); 26 return 0; 27} 28 29void __delay(unsigned long cycles) 30{ 31 cycles_t start = get_cycles(); 32 33 while ((get_cycles() - start) < cycles) 34 cpu_relax(); 35} 36EXPORT_SYMBOL(__delay); 37 38inline void __const_udelay(unsigned long xloops) 39{ 40 unsigned long long loops; 41 42 loops = (unsigned long long)xloops * loops_per_jiffy * HZ; 43 44 __delay(loops >> 32); 45} 46EXPORT_SYMBOL(__const_udelay); 47 48void __udelay(unsigned long usecs) 49{ 50 __const_udelay(usecs * 0x10C7UL); /* 2**32 / 1000000 (rounded up) */ 51} 52EXPORT_SYMBOL(__udelay); 53 54void __ndelay(unsigned long nsecs) 55{ 56 __const_udelay(nsecs * 0x5UL); /* 2**32 / 1000000000 (rounded up) */ 57} 58EXPORT_SYMBOL(__ndelay); 59