forked from mirrors/linux
f36eb17141
A lot of commonly used functions for inserting a sleep or delay lack a proper function description. Add function descriptions to all of them to have important information in a central place close to the code. No functional change. Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/all/20241014-devel-anna-maria-b4-timers-flseep-v3-5-dc8b907cb62f@linutronix.de
116 lines
3.3 KiB
C
116 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#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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* Sleep routines using timer list timers or hrtimers.
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*/
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#include <linux/math.h>
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#include <linux/sched.h>
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extern unsigned long loops_per_jiffy;
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#include <asm/delay.h>
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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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#ifndef mdelay
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/**
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* mdelay - Inserting a delay based on milliseconds with busy waiting
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* @n: requested delay in milliseconds
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*
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* See udelay() for basic information about mdelay() and it's variants.
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*
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* Please double check, whether mdelay() is the right way to go or whether a
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* refactoring of the code is the better variant to be able to use msleep()
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* instead.
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*/
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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 __ms=(n); while (__ms--) udelay(1000);}))
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#endif
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#ifndef ndelay
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static inline void ndelay(unsigned long x)
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{
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udelay(DIV_ROUND_UP(x, 1000));
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}
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#define ndelay(x) ndelay(x)
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#endif
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extern unsigned long lpj_fine;
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void calibrate_delay(void);
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unsigned long calibrate_delay_is_known(void);
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void __attribute__((weak)) calibration_delay_done(void);
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void msleep(unsigned int msecs);
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unsigned long msleep_interruptible(unsigned int msecs);
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void usleep_range_state(unsigned long min, unsigned long max,
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unsigned int state);
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/**
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* usleep_range - Sleep for an approximate time
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* @min: Minimum time in microseconds to sleep
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* @max: Maximum time in microseconds to sleep
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*
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* For basic information please refere to usleep_range_state().
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*
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* The task will be in the state TASK_UNINTERRUPTIBLE during the sleep.
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*/
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static inline void usleep_range(unsigned long min, unsigned long max)
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{
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usleep_range_state(min, max, TASK_UNINTERRUPTIBLE);
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}
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/**
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* usleep_range_idle - Sleep for an approximate time with idle time accounting
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* @min: Minimum time in microseconds to sleep
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* @max: Maximum time in microseconds to sleep
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*
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* For basic information please refere to usleep_range_state().
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*
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* The sleeping task has the state TASK_IDLE during the sleep to prevent
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* contribution to the load avarage.
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*/
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static inline void usleep_range_idle(unsigned long min, unsigned long max)
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{
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usleep_range_state(min, max, TASK_IDLE);
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}
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/**
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* ssleep - wrapper for seconds around msleep
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* @seconds: Requested sleep duration in seconds
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*
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* Please refere to msleep() for detailed information.
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*/
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static inline void ssleep(unsigned int seconds)
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{
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msleep(seconds * 1000);
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}
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/* see Documentation/timers/timers-howto.rst for the thresholds */
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static inline void fsleep(unsigned long usecs)
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{
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if (usecs <= 10)
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udelay(usecs);
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else if (usecs <= 20000)
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usleep_range(usecs, 2 * usecs);
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else
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msleep(DIV_ROUND_UP(usecs, 1000));
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}
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#endif /* defined(_LINUX_DELAY_H) */
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