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/delay.h> 12 #include <linux/export.h> 13 #include <linux/param.h> 14 #include <linux/smp.h> 15 #include <linux/stringify.h> 16 17 #include <asm/asm.h> 18 #include <asm/compiler.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 #ifndef CONFIG_HAVE_PLAT_DELAY 27 28 void __delay(unsigned long loops) 29 { 30 __asm__ __volatile__ ( 31 " .set noreorder \n" 32 " .align 3 \n" 33 "1: bnez %0, 1b \n" 34 " " __stringify(LONG_SUBU) " %0, %1 \n" 35 " .set reorder \n" 36 : "=r" (loops) 37 : GCC_DADDI_IMM_ASM() (1), "0" (loops)); 38 } 39 EXPORT_SYMBOL(__delay); 40 41 /* 42 * Division by multiplication: you don't have to worry about 43 * loss of precision. 44 * 45 * Use only for very small delays ( < 1 msec). Should probably use a 46 * lookup table, really, as the multiplications take much too long with 47 * short delays. This is a "reasonable" implementation, though (and the 48 * first constant multiplications gets optimized away if the delay is 49 * a constant) 50 */ 51 52 void __udelay(unsigned long us) 53 { 54 unsigned int lpj = raw_current_cpu_data.udelay_val; 55 56 __delay((us * 0x000010c7ull * HZ * lpj) >> 32); 57 } 58 EXPORT_SYMBOL(__udelay); 59 60 void __ndelay(unsigned long ns) 61 { 62 unsigned int lpj = raw_current_cpu_data.udelay_val; 63 64 __delay((ns * 0x00000005ull * HZ * lpj) >> 32); 65 } 66 EXPORT_SYMBOL(__ndelay); 67 68 #endif 69