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caab277b | 1 | // SPDX-License-Identifier: GPL-2.0-only |
f27bb139 MZ |
2 | /* |
3 | * Delay loops based on the OpenRISC implementation. | |
4 | * | |
5 | * Copyright (C) 2012 ARM Limited | |
6 | * | |
f27bb139 MZ |
7 | * Author: Will Deacon <will.deacon@arm.com> |
8 | */ | |
9 | ||
10 | #include <linux/delay.h> | |
11 | #include <linux/init.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/timex.h> | |
15 | ||
7b77452e JT |
16 | #include <clocksource/arm_arch_timer.h> |
17 | ||
18 | #define USECS_TO_CYCLES(time_usecs) \ | |
19 | xloops_to_cycles((time_usecs) * 0x10C7UL) | |
20 | ||
21 | static inline unsigned long xloops_to_cycles(unsigned long xloops) | |
22 | { | |
23 | return (xloops * loops_per_jiffy * HZ) >> 32; | |
24 | } | |
25 | ||
f27bb139 MZ |
26 | void __delay(unsigned long cycles) |
27 | { | |
28 | cycles_t start = get_cycles(); | |
29 | ||
7b77452e JT |
30 | if (arch_timer_evtstrm_available()) { |
31 | const cycles_t timer_evt_period = | |
32 | USECS_TO_CYCLES(ARCH_TIMER_EVT_STREAM_PERIOD_US); | |
33 | ||
34 | while ((get_cycles() - start + timer_evt_period) < cycles) | |
35 | wfe(); | |
36 | } | |
37 | ||
f27bb139 MZ |
38 | while ((get_cycles() - start) < cycles) |
39 | cpu_relax(); | |
40 | } | |
41 | EXPORT_SYMBOL(__delay); | |
42 | ||
43 | inline void __const_udelay(unsigned long xloops) | |
44 | { | |
7b77452e | 45 | __delay(xloops_to_cycles(xloops)); |
f27bb139 MZ |
46 | } |
47 | EXPORT_SYMBOL(__const_udelay); | |
48 | ||
49 | void __udelay(unsigned long usecs) | |
50 | { | |
51 | __const_udelay(usecs * 0x10C7UL); /* 2**32 / 1000000 (rounded up) */ | |
52 | } | |
53 | EXPORT_SYMBOL(__udelay); | |
54 | ||
55 | void __ndelay(unsigned long nsecs) | |
56 | { | |
57 | __const_udelay(nsecs * 0x5UL); /* 2**32 / 1000000000 (rounded up) */ | |
58 | } | |
59 | EXPORT_SYMBOL(__ndelay); |