92 lines
2.4 KiB
C
92 lines
2.4 KiB
C
/* 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:
|
|
* https://lists.openwall.net/linux-kernel/2011/01/09/56
|
|
*/
|
|
|
|
#include <linux/math.h>
|
|
#include <linux/sched.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.
|
|
*/
|
|
|
|
#ifndef MAX_UDELAY_MS
|
|
#define MAX_UDELAY_MS 5
|
|
#endif
|
|
|
|
#ifndef mdelay
|
|
#define mdelay(n) (\
|
|
(__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
|
|
({unsigned long __ms=(n); while (__ms--) udelay(1000);}))
|
|
#endif
|
|
|
|
#ifndef ndelay
|
|
static inline void ndelay(unsigned long x)
|
|
{
|
|
udelay(DIV_ROUND_UP(x, 1000));
|
|
}
|
|
#define ndelay(x) ndelay(x)
|
|
#endif
|
|
|
|
extern unsigned long lpj_fine;
|
|
void calibrate_delay(void);
|
|
void __attribute__((weak)) calibration_delay_done(void);
|
|
void msleep(unsigned int msecs);
|
|
unsigned long msleep_interruptible(unsigned int msecs);
|
|
void usleep_range_state(unsigned long min, unsigned long max,
|
|
unsigned int state);
|
|
|
|
static inline void usleep_range(unsigned long min, unsigned long max)
|
|
{
|
|
usleep_range_state(min, max, TASK_UNINTERRUPTIBLE);
|
|
}
|
|
|
|
static inline void usleep_idle_range(unsigned long min, unsigned long max)
|
|
{
|
|
usleep_range_state(min, max, TASK_IDLE);
|
|
}
|
|
|
|
static inline void ssleep(unsigned int seconds)
|
|
{
|
|
msleep(seconds * 1000);
|
|
}
|
|
|
|
/* see Documentation/timers/timers-howto.rst for the thresholds */
|
|
static inline void fsleep(unsigned long usecs)
|
|
{
|
|
if (usecs <= 10)
|
|
udelay(usecs);
|
|
else if (usecs <= 20000)
|
|
usleep_range(usecs, 2 * usecs);
|
|
else
|
|
msleep(DIV_ROUND_UP(usecs, 1000));
|
|
}
|
|
|
|
#endif /* defined(_LINUX_DELAY_H) */
|