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1da177e4 LT |
1 | /* delay.h: FRV delay code |
2 | * | |
3 | * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #ifndef _ASM_DELAY_H | |
13 | #define _ASM_DELAY_H | |
14 | ||
15 | #include <asm/param.h> | |
16 | #include <asm/timer-regs.h> | |
17 | ||
18 | /* | |
19 | * delay loop - runs at __core_clock_speed_HZ / 2 [there are 2 insns in the loop] | |
20 | */ | |
21 | extern unsigned long __delay_loops_MHz; | |
22 | ||
23 | static inline void __delay(unsigned long loops) | |
24 | { | |
25 | asm volatile("1: subicc %0,#1,%0,icc0 \n" | |
26 | " bnc icc0,#2,1b \n" | |
27 | : "=r" (loops) | |
28 | : "0" (loops) | |
29 | : "icc0" | |
30 | ); | |
31 | } | |
32 | ||
33 | /* | |
34 | * Use only for very small delays ( < 1 msec). Should probably use a | |
35 | * lookup table, really, as the multiplications take much too long with | |
36 | * short delays. This is a "reasonable" implementation, though (and the | |
37 | * first constant multiplications gets optimized away if the delay is | |
38 | * a constant) | |
39 | */ | |
40 | ||
41 | extern unsigned long loops_per_jiffy; | |
42 | ||
43 | static inline void udelay(unsigned long usecs) | |
44 | { | |
45 | __delay(usecs * __delay_loops_MHz); | |
46 | } | |
47 | ||
48 | #define ndelay(n) udelay((n) * 5) | |
49 | ||
50 | #endif /* _ASM_DELAY_H */ |