1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef _LINUX_DELAY_H
 3#define _LINUX_DELAY_H
 4
 5/*
 6 * Copyright (C) 1993 Linus Torvalds
 7 *
 8 * Delay routines, using a pre-computed "loops_per_jiffy" value.
 9 *
10 * Please note that ndelay(), udelay() and mdelay() may return early for
11 * several reasons:
12 *  1. computed loops_per_jiffy too low (due to the time taken to
13 *     execute the timer interrupt.)
14 *  2. cache behaviour affecting the time it takes to execute the
15 *     loop function.
16 *  3. CPU clock rate changes.
17 *
18 * Please see this thread:
19 *   https://lists.openwall.net/linux-kernel/2011/01/09/56
20 */
21
22#include <linux/kernel.h>
23
24extern unsigned long loops_per_jiffy;
25
26#include <asm/delay.h>
27
28/*
29 * Using udelay() for intervals greater than a few milliseconds can
30 * risk overflow for high loops_per_jiffy (high bogomips) machines. The
31 * mdelay() provides a wrapper to prevent this.  For delays greater
32 * than MAX_UDELAY_MS milliseconds, the wrapper is used.  Architecture
33 * specific values can be defined in asm-???/delay.h as an override.
34 * The 2nd mdelay() definition ensures GCC will optimize away the 
35 * while loop for the common cases where n <= MAX_UDELAY_MS  --  Paul G.
36 */
37
38#ifndef MAX_UDELAY_MS
39#define MAX_UDELAY_MS	5
40#endif
41
42#ifndef mdelay
43#define mdelay(n) (\
44	(__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
45	({unsigned long __ms=(n); while (__ms--) udelay(1000);}))
46#endif
47
48#ifndef ndelay
49static inline void ndelay(unsigned long x)
50{
51	udelay(DIV_ROUND_UP(x, 1000));
52}
53#define ndelay(x) ndelay(x)
54#endif
55
56extern unsigned long lpj_fine;
57void calibrate_delay(void);
58void __attribute__((weak)) calibration_delay_done(void);
59void msleep(unsigned int msecs);
60unsigned long msleep_interruptible(unsigned int msecs);
61void usleep_range(unsigned long min, unsigned long max);
62
63static inline void ssleep(unsigned int seconds)
64{
65	msleep(seconds * 1000);
66}
67
68/* see Documentation/timers/timers-howto.rst for the thresholds */
69static inline void fsleep(unsigned long usecs)
70{
71	if (usecs <= 10)
72		udelay(usecs);
73	else if (usecs <= 20000)
74		usleep_range(usecs, 2 * usecs);
75	else
76		msleep(DIV_ROUND_UP(usecs, 1000));
77}
78
79#endif /* defined(_LINUX_DELAY_H) */

 
 1#ifndef _LINUX_DELAY_H
 2#define _LINUX_DELAY_H
 3
 4/*
 5 * Copyright (C) 1993 Linus Torvalds
 6 *
 7 * Delay routines, using a pre-computed "loops_per_jiffy" value.
 
 
 
 
 
 
 
 
 
 
 
 8 */
 9
10#include <linux/kernel.h>
11
12extern unsigned long loops_per_jiffy;
13
14#include <asm/delay.h>
15
16/*
17 * Using udelay() for intervals greater than a few milliseconds can
18 * risk overflow for high loops_per_jiffy (high bogomips) machines. The
19 * mdelay() provides a wrapper to prevent this.  For delays greater
20 * than MAX_UDELAY_MS milliseconds, the wrapper is used.  Architecture
21 * specific values can be defined in asm-???/delay.h as an override.
22 * The 2nd mdelay() definition ensures GCC will optimize away the 
23 * while loop for the common cases where n <= MAX_UDELAY_MS  --  Paul G.
24 */
25
26#ifndef MAX_UDELAY_MS
27#define MAX_UDELAY_MS	5
28#endif
29
30#ifndef mdelay
31#define mdelay(n) (\
32	(__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
33	({unsigned long __ms=(n); while (__ms--) udelay(1000);}))
34#endif
35
36#ifndef ndelay
37static inline void ndelay(unsigned long x)
38{
39	udelay(DIV_ROUND_UP(x, 1000));
40}
41#define ndelay(x) ndelay(x)
42#endif
43
44extern unsigned long lpj_fine;
45void calibrate_delay(void);
 
46void msleep(unsigned int msecs);
47unsigned long msleep_interruptible(unsigned int msecs);
48void usleep_range(unsigned long min, unsigned long max);
49
50static inline void ssleep(unsigned int seconds)
51{
52	msleep(seconds * 1000);
 
 
 
 
 
 
 
 
 
 
 
53}
54
55#endif /* defined(_LINUX_DELAY_H) */