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delay.h
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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.
8  */
9 
10 #include <linux/kernel.h>
11 
12 extern unsigned long loops_per_jiffy;
13 
14 #include <asm/delay.h>
15 
16 /*
17  * Using udelay() for intervals greater than a few milliseconds can
18  * risk overflow for high loops_per_jiffy (high bogomips) machines. The
19  * mdelay() provides a wrapper to prevent this. For delays greater
20  * than MAX_UDELAY_MS milliseconds, the wrapper is used. Architecture
21  * specific values can be defined in asm-???/delay.h as an override.
22  * The 2nd mdelay() definition ensures GCC will optimize away the
23  * while loop for the common cases where n <= MAX_UDELAY_MS -- Paul G.
24  */
25 
26 #ifndef MAX_UDELAY_MS
27 #define MAX_UDELAY_MS 5
28 #endif
29 
30 #ifndef mdelay
31 #define mdelay(n) (\
32  (__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
33  ({unsigned long __ms=(n); while (__ms--) udelay(1000);}))
34 #endif
35 
36 #ifndef ndelay
37 static inline void ndelay(unsigned long x)
38 {
39  udelay(DIV_ROUND_UP(x, 1000));
40 }
41 #define ndelay(x) ndelay(x)
42 #endif
43 
44 extern unsigned long lpj_fine;
45 void calibrate_delay(void);
46 void msleep(unsigned int msecs);
47 unsigned long msleep_interruptible(unsigned int msecs);
48 void usleep_range(unsigned long min, unsigned long max);
49 
50 static inline void ssleep(unsigned int seconds)
51 {
52  msleep(seconds * 1000);
53 }
54 
55 #endif /* defined(_LINUX_DELAY_H) */