projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
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 | */ | |
| 10 | #ifndef _ASM_DELAY_H | |
| 11 | #define _ASM_DELAY_H | |
| 12 | ||
| 1da177e4 | 13 | #include <linux/param.h> |
| 88de09f3 | 14 | #include <linux/smp.h> |
| 1da177e4 LT |
15 | #include <asm/compiler.h> |
| 16 | ||
| 1da177e4 LT |
17 | static inline void __delay(unsigned long loops) |
| 18 | { | |
| 19 | if (sizeof(long) == 4) | |
| 20 | __asm__ __volatile__ ( | |
| 5ee82350 RB |
21 | " .set noreorder \n" |
| 22 | " .align 3 \n" | |
| 23 | "1: bnez %0, 1b \n" | |
| 24 | " subu %0, 1 \n" | |
| 25 | " .set reorder \n" | |
| 1da177e4 LT |
26 | : "=r" (loops) |
| 27 | : "0" (loops)); | |
| 28 | else if (sizeof(long) == 8) | |
| 29 | __asm__ __volatile__ ( | |
| 5ee82350 RB |
30 | " .set noreorder \n" |
| 31 | " .align 3 \n" | |
| 32 | "1: bnez %0, 1b \n" | |
| 33 | " dsubu %0, 1 \n" | |
| 34 | " .set reorder \n" | |
| 35 | : "=r" (loops) | |
| 36 | : "0" (loops)); | |
| 1da177e4 LT |
37 | } |
| 38 | ||
| 39 | ||
| 40 | /* | |
| 41 | * Division by multiplication: you don't have to worry about | |
| 42 | * loss of precision. | |
| 43 | * | |
| 44 | * Use only for very small delays ( < 1 msec). Should probably use a | |
| 45 | * lookup table, really, as the multiplications take much too long with | |
| 46 | * short delays. This is a "reasonable" implementation, though (and the | |
| 47 | * first constant multiplications gets optimized away if the delay is | |
| 48 | * a constant) | |
| 49 | */ | |
| 50 | ||
| 51 | static inline void __udelay(unsigned long usecs, unsigned long lpj) | |
| 52 | { | |
| 53 | unsigned long lo; | |
| 54 | ||
| 55 | /* | |
| f12555d2 AN |
56 | * The rates of 128 is rounded wrongly by the catchall case |
| 57 | * for 64-bit. Excessive precission? Probably ... | |
| 1da177e4 | 58 | */ |
| 875d43e7 | 59 | #if defined(CONFIG_64BIT) && (HZ == 128) |
| 1da177e4 | 60 | usecs *= 0x0008637bd05af6c7UL; /* 2**64 / (1000000 / HZ) */ |
| 875d43e7 | 61 | #elif defined(CONFIG_64BIT) |
| 1da177e4 LT |
62 | usecs *= (0x8000000000000000UL / (500000 / HZ)); |
| 63 | #else /* 32-bit junk follows here */ | |
| 64 | usecs *= (unsigned long) (((0x8000000000000000ULL / (500000 / HZ)) + | |
| 65 | 0x80000000ULL) >> 32); | |
| 66 | #endif | |
| 67 | ||
| 68 | if (sizeof(long) == 4) | |
| 69 | __asm__("multu\t%2, %3" | |
| 70 | : "=h" (usecs), "=l" (lo) | |
| 71 | : "r" (usecs), "r" (lpj) | |
| 72 | : GCC_REG_ACCUM); | |
| 73 | else if (sizeof(long) == 8) | |
| 74 | __asm__("dmultu\t%2, %3" | |
| 75 | : "=h" (usecs), "=l" (lo) | |
| 76 | : "r" (usecs), "r" (lpj) | |
| 77 | : GCC_REG_ACCUM); | |
| 78 | ||
| 79 | __delay(usecs); | |
| 80 | } | |
| 81 | ||
| 83598f1c | 82 | #define __udelay_val cpu_data[raw_smp_processor_id()].udelay_val |
| 1da177e4 LT |
83 | |
| 84 | #define udelay(usecs) __udelay((usecs),__udelay_val) | |
| 85 | ||
| a0f08209 AN |
86 | /* make sure "usecs *= ..." in udelay do not overflow. */ |
| 87 | #if HZ >= 1000 | |
| 88 | #define MAX_UDELAY_MS 1 | |
| 89 | #elif HZ <= 200 | |
| 90 | #define MAX_UDELAY_MS 5 | |
| 91 | #else | |
| 92 | #define MAX_UDELAY_MS (1000 / HZ) | |
| 93 | #endif | |
| 94 | ||
| 1da177e4 | 95 | #endif /* _ASM_DELAY_H */ |