| /* 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> |
| |
| 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(unsigned long min, unsigned long max); |
| |
| 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) */ |