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c55377ee PM |
1 | #ifndef _ASM_POWERPC_DELAY_H |
2 | #define _ASM_POWERPC_DELAY_H | |
1da177e4 LT |
3 | |
4 | /* | |
5 | * Copyright 1996, Paul Mackerras. | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License | |
9 | * as published by the Free Software Foundation; either version | |
10 | * 2 of the License, or (at your option) any later version. | |
11 | * | |
12 | * PPC64 Support added by Dave Engebretsen, Todd Inglett, Mike Corrigan, | |
13 | * Anton Blanchard. | |
14 | */ | |
15 | ||
16 | extern unsigned long tb_ticks_per_usec; | |
17 | ||
c55377ee PM |
18 | #ifdef CONFIG_PPC64 |
19 | /* define these here to prevent circular dependencies */ | |
20 | /* these instructions control the thread priority on multi-threaded cpus */ | |
1da177e4 LT |
21 | #define __HMT_low() asm volatile("or 1,1,1") |
22 | #define __HMT_medium() asm volatile("or 2,2,2") | |
c55377ee PM |
23 | #else |
24 | #define __HMT_low() | |
25 | #define __HMT_medium() | |
26 | #endif | |
27 | ||
28 | #define __barrier() asm volatile("" ::: "memory") | |
1da177e4 LT |
29 | |
30 | static inline unsigned long __get_tb(void) | |
31 | { | |
32 | unsigned long rval; | |
33 | ||
34 | asm volatile("mftb %0" : "=r" (rval)); | |
35 | return rval; | |
36 | } | |
37 | ||
38 | static inline void __delay(unsigned long loops) | |
39 | { | |
40 | unsigned long start = __get_tb(); | |
41 | ||
c55377ee | 42 | while((__get_tb() - start) < loops) |
1da177e4 LT |
43 | __HMT_low(); |
44 | __HMT_medium(); | |
45 | __barrier(); | |
46 | } | |
47 | ||
48 | static inline void udelay(unsigned long usecs) | |
49 | { | |
50 | unsigned long loops = tb_ticks_per_usec * usecs; | |
51 | ||
52 | __delay(loops); | |
53 | } | |
54 | ||
c55377ee | 55 | #endif /* _ASM_POWERPC_DELAY_H */ |