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, 2014 Maciej W. Rozycki 10 */ 11 #include <linux/export.h> 12 #include <linux/param.h> 13 #include <linux/smp.h> 14 #include <linux/stringify.h> 15 16 #include <asm/asm.h> 17 #include <asm/compiler.h> 18 #include <asm/war.h> 19 20 #ifndef CONFIG_CPU_DADDI_WORKAROUNDS 21 #define GCC_DADDI_IMM_ASM() "I" 22 #else 23 #define GCC_DADDI_IMM_ASM() "r" 24 #endif 25 26 void __delay(unsigned long loops) 27 { 28 __asm__ __volatile__ ( 29 " .set noreorder \n" 30 " .align 3 \n" 31 "1: bnez %0, 1b \n" 32 " " __stringify(LONG_SUBU) " %0, %1 \n" 33 " .set reorder \n" 34 : "=r" (loops) 35 : GCC_DADDI_IMM_ASM() (1), "0" (loops)); 36 } 37 EXPORT_SYMBOL(__delay); 38 39 /* 40 * Division by multiplication: you don't have to worry about 41 * loss of precision. 42 * 43 * Use only for very small delays ( < 1 msec). Should probably use a 44 * lookup table, really, as the multiplications take much too long with 45 * short delays. This is a "reasonable" implementation, though (and the 46 * first constant multiplications gets optimized away if the delay is 47 * a constant) 48 */ 49 50 void __udelay(unsigned long us) 51 { 52 unsigned int lpj = raw_current_cpu_data.udelay_val; 53 54 __delay((us * 0x000010c7ull * HZ * lpj) >> 32); 55 } 56 EXPORT_SYMBOL(__udelay); 57 58 void __ndelay(unsigned long ns) 59 { 60 unsigned int lpj = raw_current_cpu_data.udelay_val; 61 62 __delay((ns * 0x00000005ull * HZ * lpj) >> 32); 63 } 64 EXPORT_SYMBOL(__ndelay); 65