1/* 2 * Precise Delay Loops for avr32 3 * 4 * Copyright (C) 1993 Linus Torvalds 5 * Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> 6 * Copyright (C) 2005-2006 Atmel Corporation 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 13#include <linux/delay.h> 14#include <linux/module.h> 15#include <linux/timex.h> 16#include <linux/param.h> 17#include <linux/types.h> 18#include <linux/init.h> 19 20#include <asm/processor.h> 21#include <asm/sysreg.h> 22 23int __devinit read_current_timer(unsigned long *timer_value) 24{ 25 *timer_value = sysreg_read(COUNT); 26 return 0; 27} 28 29void __delay(unsigned long loops) 30{ 31 unsigned bclock, now; 32 33 bclock = sysreg_read(COUNT); 34 do { 35 now = sysreg_read(COUNT); 36 } while ((now - bclock) < loops); 37} 38 39inline void __const_udelay(unsigned long xloops) 40{ 41 unsigned long long loops; 42 43 asm("mulu.d %0, %1, %2" 44 : "=r"(loops) 45 : "r"(current_cpu_data.loops_per_jiffy * HZ), "r"(xloops)); 46 __delay(loops >> 32); 47} 48 49void __udelay(unsigned long usecs) 50{ 51 __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */ 52} 53 54void __ndelay(unsigned long nsecs) 55{ 56 __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */ 57} 58