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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_DELAY_H
#define _LINUX_DELAY_H
* Copyright (C) 1993 Linus Torvalds
* Delay routines, using a pre-computed "loops_per_jiffy" value.
* Please note that ndelay(), udelay() and mdelay() may return early for
* several reasons:
* 1. computed loops_per_jiffy too low (due to the time taken to
* execute the timer interrupt.)
* 2. cache behaviour affecting the time it takes to execute the
* loop function.
* 3. CPU clock rate changes.
* Please see this thread:
#include <linux/kernel.h>
extern unsigned long loops_per_jiffy;
#include <asm/delay.h>
* Using udelay() for intervals greater than a few milliseconds can
* risk overflow for high loops_per_jiffy (high bogomips) machines. The
* mdelay() provides a wrapper to prevent this. For delays greater
* than MAX_UDELAY_MS milliseconds, the wrapper is used. Architecture
* specific values can be defined in asm-???/delay.h as an override.
* The 2nd mdelay() definition ensures GCC will optimize away the
* while loop for the common cases where n <= MAX_UDELAY_MS -- Paul G.
#define MAX_UDELAY_MS 5
#ifndef mdelay
#define mdelay(n) (\
(__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
({unsigned long __ms=(n); while (__ms--) udelay(1000);}))
#ifndef ndelay
static inline void ndelay(unsigned long x)
udelay(DIV_ROUND_UP(x, 1000));
#define ndelay(x) ndelay(x)
extern unsigned long lpj_fine;
void calibrate_delay(void);
void msleep(unsigned int msecs);
unsigned long msleep_interruptible(unsigned int msecs);
void usleep_range(unsigned long min, unsigned long max);
static inline void ssleep(unsigned int seconds)
msleep(seconds * 1000);
#endif /* defined(_LINUX_DELAY_H) */