1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */
2*4882a593Smuzhiyun #ifndef _LINUX_DELAY_H
3*4882a593Smuzhiyun #define _LINUX_DELAY_H
4*4882a593Smuzhiyun
5*4882a593Smuzhiyun /*
6*4882a593Smuzhiyun * Copyright (C) 1993 Linus Torvalds
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun * Delay routines, using a pre-computed "loops_per_jiffy" value.
9*4882a593Smuzhiyun *
10*4882a593Smuzhiyun * Please note that ndelay(), udelay() and mdelay() may return early for
11*4882a593Smuzhiyun * several reasons:
12*4882a593Smuzhiyun * 1. computed loops_per_jiffy too low (due to the time taken to
13*4882a593Smuzhiyun * execute the timer interrupt.)
14*4882a593Smuzhiyun * 2. cache behaviour affecting the time it takes to execute the
15*4882a593Smuzhiyun * loop function.
16*4882a593Smuzhiyun * 3. CPU clock rate changes.
17*4882a593Smuzhiyun *
18*4882a593Smuzhiyun * Please see this thread:
19*4882a593Smuzhiyun * https://lists.openwall.net/linux-kernel/2011/01/09/56
20*4882a593Smuzhiyun */
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun #include <linux/kernel.h>
23*4882a593Smuzhiyun #include <linux/sched.h>
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun extern unsigned long loops_per_jiffy;
26*4882a593Smuzhiyun
27*4882a593Smuzhiyun #include <asm/delay.h>
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun /*
30*4882a593Smuzhiyun * Using udelay() for intervals greater than a few milliseconds can
31*4882a593Smuzhiyun * risk overflow for high loops_per_jiffy (high bogomips) machines. The
32*4882a593Smuzhiyun * mdelay() provides a wrapper to prevent this. For delays greater
33*4882a593Smuzhiyun * than MAX_UDELAY_MS milliseconds, the wrapper is used. Architecture
34*4882a593Smuzhiyun * specific values can be defined in asm-???/delay.h as an override.
35*4882a593Smuzhiyun * The 2nd mdelay() definition ensures GCC will optimize away the
36*4882a593Smuzhiyun * while loop for the common cases where n <= MAX_UDELAY_MS -- Paul G.
37*4882a593Smuzhiyun */
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun #ifndef MAX_UDELAY_MS
40*4882a593Smuzhiyun #define MAX_UDELAY_MS 5
41*4882a593Smuzhiyun #endif
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun #ifndef mdelay
44*4882a593Smuzhiyun #define mdelay(n) (\
45*4882a593Smuzhiyun (__builtin_constant_p(n) && (n)<=MAX_UDELAY_MS) ? udelay((n)*1000) : \
46*4882a593Smuzhiyun ({unsigned long __ms=(n); while (__ms--) udelay(1000);}))
47*4882a593Smuzhiyun #endif
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun #ifndef ndelay
ndelay(unsigned long x)50*4882a593Smuzhiyun static inline void ndelay(unsigned long x)
51*4882a593Smuzhiyun {
52*4882a593Smuzhiyun udelay(DIV_ROUND_UP(x, 1000));
53*4882a593Smuzhiyun }
54*4882a593Smuzhiyun #define ndelay(x) ndelay(x)
55*4882a593Smuzhiyun #endif
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun extern unsigned long lpj_fine;
58*4882a593Smuzhiyun void calibrate_delay(void);
59*4882a593Smuzhiyun void __attribute__((weak)) calibration_delay_done(void);
60*4882a593Smuzhiyun void msleep(unsigned int msecs);
61*4882a593Smuzhiyun unsigned long msleep_interruptible(unsigned int msecs);
62*4882a593Smuzhiyun void usleep_range_state(unsigned long min, unsigned long max,
63*4882a593Smuzhiyun unsigned int state);
64*4882a593Smuzhiyun void usleep_range(unsigned long min, unsigned long max);
65*4882a593Smuzhiyun
usleep_idle_range(unsigned long min,unsigned long max)66*4882a593Smuzhiyun static inline void usleep_idle_range(unsigned long min, unsigned long max)
67*4882a593Smuzhiyun {
68*4882a593Smuzhiyun usleep_range_state(min, max, TASK_IDLE);
69*4882a593Smuzhiyun }
70*4882a593Smuzhiyun
ssleep(unsigned int seconds)71*4882a593Smuzhiyun static inline void ssleep(unsigned int seconds)
72*4882a593Smuzhiyun {
73*4882a593Smuzhiyun msleep(seconds * 1000);
74*4882a593Smuzhiyun }
75*4882a593Smuzhiyun
76*4882a593Smuzhiyun /* see Documentation/timers/timers-howto.rst for the thresholds */
fsleep(unsigned long usecs)77*4882a593Smuzhiyun static inline void fsleep(unsigned long usecs)
78*4882a593Smuzhiyun {
79*4882a593Smuzhiyun if (usecs <= 10)
80*4882a593Smuzhiyun udelay(usecs);
81*4882a593Smuzhiyun else if (usecs <= 20000)
82*4882a593Smuzhiyun usleep_range(usecs, 2 * usecs);
83*4882a593Smuzhiyun else
84*4882a593Smuzhiyun msleep(DIV_ROUND_UP(usecs, 1000));
85*4882a593Smuzhiyun }
86*4882a593Smuzhiyun
87*4882a593Smuzhiyun #endif /* defined(_LINUX_DELAY_H) */
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