/* 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: * http://lists.openwall.net/linux-kernel/2011/01/09/56 */ #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. */ #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 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) */