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 <linux/timex.h> 19 #include <asm/param.h> 20 #include <asm/delay.h> 21 #include <asm/timex.h> 22 #include <asm/processor.h> 23 24 int read_current_timer(unsigned long *timer_value) 25 { 26 *timer_value = get_cycles(); 27 return 0; 28 } 29 30 void __delay(unsigned long cycles) 31 { 32 cycles_t start = get_cycles(); 33 34 while ((get_cycles() - start) < cycles) 35 cpu_relax(); 36 } 37 EXPORT_SYMBOL(__delay); 38 39 inline void __const_udelay(unsigned long xloops) 40 { 41 unsigned long long loops; 42 43 loops = (unsigned long long)xloops * loops_per_jiffy * HZ; 44 45 __delay(loops >> 32); 46 } 47 EXPORT_SYMBOL(__const_udelay); 48 49 void __udelay(unsigned long usecs) 50 { 51 __const_udelay(usecs * 0x10C7UL); /* 2**32 / 1000000 (rounded up) */ 52 } 53 EXPORT_SYMBOL(__udelay); 54 55 void __ndelay(unsigned long nsecs) 56 { 57 __const_udelay(nsecs * 0x5UL); /* 2**32 / 1000000000 (rounded up) */ 58 } 59 EXPORT_SYMBOL(__ndelay); 60