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1da177e4 LT |
1 | #ifndef _LINUX_DELAY_H |
2 | #define _LINUX_DELAY_H | |
3 | ||
4 | /* | |
5 | * Copyright (C) 1993 Linus Torvalds | |
6 | * | |
7 | * Delay routines, using a pre-computed "loops_per_jiffy" value. | |
9f819798 RK |
8 | * |
9 | * Please note that ndelay(), udelay() and mdelay() may return early for | |
10 | * several reasons: | |
11 | * 1. computed loops_per_jiffy too low (due to the time taken to | |
12 | * execute the timer interrupt.) | |
13 | * 2. cache behaviour affecting the time it takes to execute the | |
14 | * loop function. | |
15 | * 3. CPU clock rate changes. | |
16 | * | |
17 | * Please see this thread: | |
18 | * http://lists.openwall.net/linux-kernel/2011/01/09/56 | |
1da177e4 LT |
19 | */ |
20 | ||
5cba6d22 AM |
21 | #include <linux/kernel.h> |
22 | ||
1da177e4 LT |
23 | extern unsigned long loops_per_jiffy; |
24 | ||
25 | #include <asm/delay.h> | |
26 | ||
27 | /* | |
28 | * Using udelay() for intervals greater than a few milliseconds can | |
29 | * risk overflow for high loops_per_jiffy (high bogomips) machines. The | |
30 | * mdelay() provides a wrapper to prevent this. For delays greater | |
31 | * than MAX_UDELAY_MS milliseconds, the wrapper is used. Architecture | |
32 | * specific values can be defined in asm-???/delay.h as an override. | |
33 | * The 2nd mdelay() definition ensures GCC will optimize away the | |
34 | * while loop for the common cases where n <= MAX_UDELAY_MS -- Paul G. | |
35 | */ | |
36 | ||
37 | #ifndef MAX_UDELAY_MS | |
38 | #define MAX_UDELAY_MS 5 | |
39 | #endif | |
40 | ||
1e92a550 | 41 | #ifndef mdelay |
1da177e4 LT |
42 | #define mdelay(n) (\ |
43 | (__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \ | |
44 | ({unsigned long __ms=(n); while (__ms--) udelay(1000);})) | |
45 | #endif | |
46 | ||
47 | #ifndef ndelay | |
5cba6d22 AM |
48 | static inline void ndelay(unsigned long x) |
49 | { | |
50 | udelay(DIV_ROUND_UP(x, 1000)); | |
51 | } | |
52 | #define ndelay(x) ndelay(x) | |
1da177e4 LT |
53 | #endif |
54 | ||
f3f3149f | 55 | extern unsigned long lpj_fine; |
1da177e4 LT |
56 | void calibrate_delay(void); |
57 | void msleep(unsigned int msecs); | |
58 | unsigned long msleep_interruptible(unsigned int msecs); | |
5e7f5a17 | 59 | void usleep_range(unsigned long min, unsigned long max); |
1da177e4 LT |
60 | |
61 | static inline void ssleep(unsigned int seconds) | |
62 | { | |
63 | msleep(seconds * 1000); | |
64 | } | |
65 | ||
66 | #endif /* defined(_LINUX_DELAY_H) */ |