1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Copyright (C) 1994 by Waldorf Electronics 7 * Copyright (C) 1995 - 2000, 01, 03 by Ralf Baechle 8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc. 9 * Copyright (C) 2007 Maciej W. Rozycki 10 */ 11 #include <linux/module.h> 12 #include <linux/param.h> 13 #include <linux/smp.h> 14 15 #include <asm/compiler.h> 16 #include <asm/war.h> 17 18 void __delay(unsigned long loops) 19 { 20 __asm__ __volatile__ ( 21 " .set noreorder \n" 22 " .align 3 \n" 23 "1: bnez %0, 1b \n" 24 #if BITS_PER_LONG == 32 25 " subu %0, 1 \n" 26 #else 27 " dsubu %0, 1 \n" 28 #endif 29 " .set reorder \n" 30 : "=r" (loops) 31 : "0" (loops)); 32 } 33 EXPORT_SYMBOL(__delay); 34 35 /* 36 * Division by multiplication: you don't have to worry about 37 * loss of precision. 38 * 39 * Use only for very small delays ( < 1 msec). Should probably use a 40 * lookup table, really, as the multiplications take much too long with 41 * short delays. This is a "reasonable" implementation, though (and the 42 * first constant multiplications gets optimized away if the delay is 43 * a constant) 44 */ 45 46 void __udelay(unsigned long us) 47 { 48 unsigned int lpj = raw_current_cpu_data.udelay_val; 49 50 __delay((us * 0x000010c7ull * HZ * lpj) >> 32); 51 } 52 EXPORT_SYMBOL(__udelay); 53 54 void __ndelay(unsigned long ns) 55 { 56 unsigned int lpj = raw_current_cpu_data.udelay_val; 57 58 __delay((ns * 0x00000005ull * HZ * lpj) >> 32); 59 } 60 EXPORT_SYMBOL(__ndelay); 61