1 /* 2 * Copyright (C) 2011 Richard Weinberger <richrd@nod.at> 3 * Mostly copied from arch/x86/lib/delay.c 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 */ 9 10 #include <linux/export.h> 11 #include <linux/kernel.h> 12 #include <linux/delay.h> 13 #include <asm/param.h> 14 15 void __delay(unsigned long loops) 16 { 17 asm volatile( 18 "test %0,%0\n" 19 "jz 3f\n" 20 "jmp 1f\n" 21 22 ".align 16\n" 23 "1: jmp 2f\n" 24 25 ".align 16\n" 26 "2: dec %0\n" 27 " jnz 2b\n" 28 "3: dec %0\n" 29 30 : /* we don't need output */ 31 : "a" (loops) 32 ); 33 } 34 EXPORT_SYMBOL(__delay); 35 36 inline void __const_udelay(unsigned long xloops) 37 { 38 int d0; 39 40 xloops *= 4; 41 asm("mull %%edx" 42 : "=d" (xloops), "=&a" (d0) 43 : "1" (xloops), "0" 44 (loops_per_jiffy * (HZ/4))); 45 46 __delay(++xloops); 47 } 48 EXPORT_SYMBOL(__const_udelay); 49 50 void __udelay(unsigned long usecs) 51 { 52 __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */ 53 } 54 EXPORT_SYMBOL(__udelay); 55 56 void __ndelay(unsigned long nsecs) 57 { 58 __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */ 59 } 60 EXPORT_SYMBOL(__ndelay); 61