projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * Copyright (C) 1993, 2000 Linus Torvalds | |
| 3 | * | |
| 4 | * Delay routines, using a pre-computed "loops_per_jiffy" value. | |
| 5 | */ | |
| 6 | ||
| 1da177e4 LT |
7 | #include <linux/module.h> |
| 8 | #include <linux/sched.h> /* for udelay's use of smp_processor_id */ | |
| 9 | #include <asm/param.h> | |
| 10 | #include <asm/smp.h> | |
| 11 | #include <linux/delay.h> | |
| 12 | ||
| 13 | /* | |
| 14 | * Use only for very small delays (< 1 msec). | |
| 15 | * | |
| 16 | * The active part of our cycle counter is only 32-bits wide, and | |
| 17 | * we're treating the difference between two marks as signed. On | |
| 18 | * a 1GHz box, that's about 2 seconds. | |
| 19 | */ | |
| 20 | ||
| 21 | void | |
| 22 | __delay(int loops) | |
| 23 | { | |
| 24 | int tmp; | |
| 25 | __asm__ __volatile__( | |
| 26 | " rpcc %0\n" | |
| 27 | " addl %1,%0,%1\n" | |
| 28 | "1: rpcc %0\n" | |
| 29 | " subl %1,%0,%0\n" | |
| 30 | " bgt %0,1b" | |
| 31 | : "=&r" (tmp), "=r" (loops) : "1"(loops)); | |
| 32 | } | |
| 33 | ||
| 34 | #ifdef CONFIG_SMP | |
| 35 | #define LPJ cpu_data[smp_processor_id()].loops_per_jiffy | |
| 36 | #else | |
| 37 | #define LPJ loops_per_jiffy | |
| 38 | #endif | |
| 39 | ||
| 40 | void | |
| 41 | udelay(unsigned long usecs) | |
| 42 | { | |
| 43 | usecs *= (((unsigned long)HZ << 32) / 1000000) * LPJ; | |
| 44 | __delay((long)usecs >> 32); | |
| 45 | } | |
| 46 | EXPORT_SYMBOL(udelay); | |
| 47 | ||
| 48 | void | |
| 49 | ndelay(unsigned long nsecs) | |
| 50 | { | |
| 51 | nsecs *= (((unsigned long)HZ << 32) / 1000000000) * LPJ; | |
| 52 | __delay((long)nsecs >> 32); | |
| 53 | } | |
| 54 | EXPORT_SYMBOL(ndelay); |