| 1 |
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| 2 | #ifndef _LINUX_DELAY_H
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| 3 | #define _LINUX_DELAY_H
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| 4 |
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| 5 | |
| 6 | * Copyright (C) 1993 Linus Torvalds
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| 7 | *
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| 8 | * Delay routines, using a pre-computed "loops_per_jiffy" value.
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| 9 | *
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| 10 | * Please note that ndelay(), udelay() and mdelay() may return early for
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| 11 | * several reasons:
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| 12 | * 1. computed loops_per_jiffy too low (due to the time taken to
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| 13 | * execute the timer interrupt.)
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| 14 | * 2. cache behaviour affecting the time it takes to execute the
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| 15 | * loop function.
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| 16 | * 3. CPU clock rate changes.
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| 17 | *
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| 18 | * Please see this thread:
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| 19 | * http://lists.openwall.net/linux-kernel/2011/01/09/56
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| 20 |
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| 21 |
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| 22 | #include <linux/kernel.h>
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| 23 |
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| 24 | extern unsigned long loops_per_jiffy;
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| 25 |
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| 26 | #include <asm/delay.h>
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| 27 |
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| 28 | |
| 29 | * Using udelay() for intervals greater than a few milliseconds can
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| 30 | * risk overflow for high loops_per_jiffy (high bogomips) machines. The
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| 31 | * mdelay() provides a wrapper to prevent this. For delays greater
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| 32 | * than MAX_UDELAY_MS milliseconds, the wrapper is used. Architecture
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| 33 | * specific values can be defined in asm-???/delay.h as an override.
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| 34 | * The 2nd mdelay() definition ensures GCC will optimize away the
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| 35 | * while loop for the common cases where n <= MAX_UDELAY_MS -- Paul G.
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| 36 |
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| 37 |
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| 38 | #ifndef MAX_UDELAY_MS
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| 39 | #define MAX_UDELAY_MS 5
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| 40 | #endif
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| 41 |
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| 42 | #ifndef mdelay
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| 43 | #define mdelay(n) (\
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| 44 | (__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
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| 45 | ({unsigned long __ms=(n); while (__ms--) udelay(1000);}))
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| 46 | #endif
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| 47 |
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| 48 | #ifndef ndelay
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| 49 | static inline void ndelay(unsigned long x)
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| 50 | {
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| 51 | udelay(DIV_ROUND_UP(x, 1000));
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| 52 | }
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| 53 | #define ndelay(x) ndelay(x)
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| 54 | #endif
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| 55 |
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| 56 | extern unsigned long lpj_fine;
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| 57 | void calibrate_delay(void);
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| 58 | void __attribute__((weak)) calibration_delay_done(void);
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| 59 | void msleep(unsigned int msecs);
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| 60 | unsigned long msleep_interruptible(unsigned int msecs);
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| 61 | void usleep_range(unsigned long min, unsigned long max);
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| 62 |
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| 63 | static inline void ssleep(unsigned int seconds)
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| 64 | {
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| 65 | msleep(seconds * 1000);
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| 66 | }
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| 67 |
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| 68 |
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| 69 | static inline void fsleep(unsigned long usecs)
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| 70 | {
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| 71 | if (usecs <= 10)
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| 72 | udelay(usecs);
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| 73 | else if (usecs <= 20000)
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| 74 | usleep_range(usecs, 2 * usecs);
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| 75 | else
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| 76 | msleep(DIV_ROUND_UP(usecs, 1000));
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| 77 | }
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| 78 |
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| 79 | #endif
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