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 #ifndef _ASM_DELAY_H 12 #define _ASM_DELAY_H 13 14 #include <linux/param.h> 15 #include <linux/smp.h> 16 17 #include <asm/compiler.h> 18 #include <asm/war.h> 19 20 static inline void __delay(unsigned long loops) 21 { 22 if (sizeof(long) == 4) 23 __asm__ __volatile__ ( 24 " .set noreorder \n" 25 " .align 3 \n" 26 "1: bnez %0, 1b \n" 27 " subu %0, 1 \n" 28 " .set reorder \n" 29 : "=r" (loops) 30 : "0" (loops)); 31 else if (sizeof(long) == 8 && !DADDI_WAR) 32 __asm__ __volatile__ ( 33 " .set noreorder \n" 34 " .align 3 \n" 35 "1: bnez %0, 1b \n" 36 " dsubu %0, 1 \n" 37 " .set reorder \n" 38 : "=r" (loops) 39 : "0" (loops)); 40 else if (sizeof(long) == 8 && DADDI_WAR) 41 __asm__ __volatile__ ( 42 " .set noreorder \n" 43 " .align 3 \n" 44 "1: bnez %0, 1b \n" 45 " dsubu %0, %2 \n" 46 " .set reorder \n" 47 : "=r" (loops) 48 : "0" (loops), "r" (1)); 49 } 50 51 52 /* 53 * Division by multiplication: you don't have to worry about 54 * loss of precision. 55 * 56 * Use only for very small delays ( < 1 msec). Should probably use a 57 * lookup table, really, as the multiplications take much too long with 58 * short delays. This is a "reasonable" implementation, though (and the 59 * first constant multiplications gets optimized away if the delay is 60 * a constant) 61 */ 62 63 static inline void __udelay(unsigned long usecs, unsigned long lpj) 64 { 65 unsigned long hi, lo; 66 67 /* 68 * The rates of 128 is rounded wrongly by the catchall case 69 * for 64-bit. Excessive precission? Probably ... 70 */ 71 #if defined(CONFIG_64BIT) && (HZ == 128) 72 usecs *= 0x0008637bd05af6c7UL; /* 2**64 / (1000000 / HZ) */ 73 #elif defined(CONFIG_64BIT) 74 usecs *= (0x8000000000000000UL / (500000 / HZ)); 75 #else /* 32-bit junk follows here */ 76 usecs *= (unsigned long) (((0x8000000000000000ULL / (500000 / HZ)) + 77 0x80000000ULL) >> 32); 78 #endif 79 80 if (sizeof(long) == 4) 81 __asm__("multu\t%2, %3" 82 : "=h" (usecs), "=l" (lo) 83 : "r" (usecs), "r" (lpj) 84 : GCC_REG_ACCUM); 85 else if (sizeof(long) == 8 && !R4000_WAR) 86 __asm__("dmultu\t%2, %3" 87 : "=h" (usecs), "=l" (lo) 88 : "r" (usecs), "r" (lpj) 89 : GCC_REG_ACCUM); 90 else if (sizeof(long) == 8 && R4000_WAR) 91 __asm__("dmultu\t%3, %4\n\tmfhi\t%0" 92 : "=r" (usecs), "=h" (hi), "=l" (lo) 93 : "r" (usecs), "r" (lpj) 94 : GCC_REG_ACCUM); 95 96 __delay(usecs); 97 } 98 99 #define __udelay_val cpu_data[raw_smp_processor_id()].udelay_val 100 101 #define udelay(usecs) __udelay((usecs), __udelay_val) 102 103 /* make sure "usecs *= ..." in udelay do not overflow. */ 104 #if HZ >= 1000 105 #define MAX_UDELAY_MS 1 106 #elif HZ <= 200 107 #define MAX_UDELAY_MS 5 108 #else 109 #define MAX_UDELAY_MS (1000 / HZ) 110 #endif 111 112 #endif /* _ASM_DELAY_H */ 113
