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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:
- * 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) */
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