93 lines
2.3 KiB
C
93 lines
2.3 KiB
C
#ifndef _LINUX_DELAY_H
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#define _LINUX_DELAY_H
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/*
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* Copyright (C) 1993 Linus Torvalds
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*
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* Delay routines, using a pre-computed "loops_per_jiffy" value.
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*/
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extern unsigned long loops_per_jiffy;
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#include <linux/time.h>
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#include <linux/sched.h>
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#include <asm/delay.h>
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/*
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* Convert jiffies to milliseconds and back.
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*
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* Avoid unnecessary multiplications/divisions in the
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* two most common HZ cases:
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*/
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static inline unsigned int jiffies_to_msecs(const unsigned long j)
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{
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#if HZ <= 1000 && !(1000 % HZ)
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return (1000 / HZ) * j;
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#elif HZ > 1000 && !(HZ % 1000)
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return (j + (HZ / 1000) - 1)/(HZ / 1000);
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#else
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return (j * 1000) / HZ;
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#endif
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}
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static inline unsigned int jiffies_to_usecs(const unsigned long j)
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{
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#if HZ <= 1000 && !(1000 % HZ)
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return (1000000 / HZ) * j;
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#elif HZ > 1000 && !(HZ % 1000)
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return (j*1000 + (HZ - 1000))/(HZ / 1000);
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#else
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return (j * 1000000) / HZ;
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#endif
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}
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static inline unsigned long msecs_to_jiffies(const unsigned int m)
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{
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if (m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
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return MAX_JIFFY_OFFSET;
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#if HZ <= 1000 && !(1000 % HZ)
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return (m + (1000 / HZ) - 1) / (1000 / HZ);
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#elif HZ > 1000 && !(HZ % 1000)
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return m * (HZ / 1000);
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#else
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return (m * HZ + 999) / 1000;
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#endif
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}
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static inline void msleep(unsigned long msecs)
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{
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set_current_state(TASK_UNINTERRUPTIBLE);
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schedule_timeout(msecs_to_jiffies(msecs) + 1);
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}
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static inline void ssleep(unsigned long secs)
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{
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set_current_state(TASK_UNINTERRUPTIBLE);
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schedule_timeout((HZ * secs) + 1);
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}
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/*
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* Using udelay() for intervals greater than a few milliseconds can
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* risk overflow for high loops_per_jiffy (high bogomips) machines. The
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* mdelay() provides a wrapper to prevent this. For delays greater
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* than MAX_UDELAY_MS milliseconds, the wrapper is used. Architecture
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* specific values can be defined in asm-???/delay.h as an override.
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* The 2nd mdelay() definition ensures GCC will optimize away the
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* while loop for the common cases where n <= MAX_UDELAY_MS -- Paul G.
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*/
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#ifndef MAX_UDELAY_MS
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#define MAX_UDELAY_MS 5
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#endif
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#ifdef notdef
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#define mdelay(n) (\
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{unsigned long msec=(n); while (msec--) udelay(1000);})
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#else
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#define mdelay(n) (\
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(__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
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({unsigned long msec=(n); while (msec--) udelay(1000);}))
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#endif
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#endif /* defined(_LINUX_DELAY_H) */
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