projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * Copyright (C) 1995-2004 Russell King | |
| 3 | * | |
| 4 | * Delay routines, using a pre-computed "loops_per_second" value. | |
| 5 | */ | |
| 6 | #ifndef __ASM_ARM_DELAY_H | |
| 7 | #define __ASM_ARM_DELAY_H | |
| 8 | ||
| d0a533b1 | 9 | #include <asm/memory.h> |
| 6d4518d7 PT |
10 | #include <asm/param.h> /* HZ */ |
| 11 | ||
| d0a533b1 | 12 | #define MAX_UDELAY_MS 2 |
| 215e362d NP |
13 | #define UDELAY_MULT UL(2047 * HZ + 483648 * HZ / 1000000) |
| 14 | #define UDELAY_SHIFT 31 | |
| d0a533b1 WD |
15 | |
| 16 | #ifndef __ASSEMBLY__ | |
| 17 | ||
| 56942fec JA |
18 | struct delay_timer { |
| 19 | unsigned long (*read_current_timer)(void); | |
| 20 | unsigned long freq; | |
| 21 | }; | |
| 22 | ||
| d0a533b1 WD |
23 | extern struct arm_delay_ops { |
| 24 | void (*delay)(unsigned long); | |
| 25 | void (*const_udelay)(unsigned long); | |
| 26 | void (*udelay)(unsigned long); | |
| 6f3d90e5 | 27 | unsigned long ticks_per_jiffy; |
| d0a533b1 WD |
28 | } arm_delay_ops; |
| 29 | ||
| 30 | #define __delay(n) arm_delay_ops.delay(n) | |
| 1da177e4 LT |
31 | |
| 32 | /* | |
| 33 | * This function intentionally does not exist; if you see references to | |
| 34 | * it, it means that you're calling udelay() with an out of range value. | |
| 35 | * | |
| 36 | * With currently imposed limits, this means that we support a max delay | |
| 215e362d | 37 | * of 2000us. Further limits: HZ<=1000 |
| 1da177e4 LT |
38 | */ |
| 39 | extern void __bad_udelay(void); | |
| 40 | ||
| 41 | /* | |
| 42 | * division by multiplication: you don't have to worry about | |
| 43 | * loss of precision. | |
| 44 | * | |
| d0a533b1 | 45 | * Use only for very small delays ( < 2 msec). Should probably use a |
| 1da177e4 LT |
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 | */ | |
| d0a533b1 WD |
51 | #define __udelay(n) arm_delay_ops.udelay(n) |
| 52 | #define __const_udelay(n) arm_delay_ops.const_udelay(n) | |
| 1da177e4 | 53 | |
| 6d4518d7 PT |
54 | #define udelay(n) \ |
| 55 | (__builtin_constant_p(n) ? \ | |
| 56 | ((n) > (MAX_UDELAY_MS * 1000) ? __bad_udelay() : \ | |
| d0a533b1 | 57 | __const_udelay((n) * UDELAY_MULT)) : \ |
| 1da177e4 LT |
58 | __udelay(n)) |
| 59 | ||
| d0a533b1 WD |
60 | /* Loop-based definitions for assembly code. */ |
| 61 | extern void __loop_delay(unsigned long loops); | |
| 62 | extern void __loop_udelay(unsigned long usecs); | |
| 63 | extern void __loop_const_udelay(unsigned long); | |
| 64 | ||
| 56942fec JA |
65 | /* Delay-loop timer registration. */ |
| 66 | #define ARCH_HAS_READ_CURRENT_TIMER | |
| 67 | extern void register_current_timer_delay(const struct delay_timer *timer); | |
| 68 | ||
| d0a533b1 WD |
69 | #endif /* __ASSEMBLY__ */ |
| 70 | ||
| 1da177e4 LT |
71 | #endif /* defined(_ARM_DELAY_H) */ |
| 72 |