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f27bb139 MZ |
1 | /* |
2 | * Delay loops based on the OpenRISC implementation. | |
3 | * | |
4 | * Copyright (C) 2012 ARM Limited | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
17 | * | |
18 | * Author: Will Deacon <will.deacon@arm.com> | |
19 | */ | |
20 | ||
21 | #include <linux/delay.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/kernel.h> | |
24 | #include <linux/module.h> | |
25 | #include <linux/timex.h> | |
26 | ||
7b77452e JT |
27 | #include <clocksource/arm_arch_timer.h> |
28 | ||
29 | #define USECS_TO_CYCLES(time_usecs) \ | |
30 | xloops_to_cycles((time_usecs) * 0x10C7UL) | |
31 | ||
32 | static inline unsigned long xloops_to_cycles(unsigned long xloops) | |
33 | { | |
34 | return (xloops * loops_per_jiffy * HZ) >> 32; | |
35 | } | |
36 | ||
f27bb139 MZ |
37 | void __delay(unsigned long cycles) |
38 | { | |
39 | cycles_t start = get_cycles(); | |
40 | ||
7b77452e JT |
41 | if (arch_timer_evtstrm_available()) { |
42 | const cycles_t timer_evt_period = | |
43 | USECS_TO_CYCLES(ARCH_TIMER_EVT_STREAM_PERIOD_US); | |
44 | ||
45 | while ((get_cycles() - start + timer_evt_period) < cycles) | |
46 | wfe(); | |
47 | } | |
48 | ||
f27bb139 MZ |
49 | while ((get_cycles() - start) < cycles) |
50 | cpu_relax(); | |
51 | } | |
52 | EXPORT_SYMBOL(__delay); | |
53 | ||
54 | inline void __const_udelay(unsigned long xloops) | |
55 | { | |
7b77452e | 56 | __delay(xloops_to_cycles(xloops)); |
f27bb139 MZ |
57 | } |
58 | EXPORT_SYMBOL(__const_udelay); | |
59 | ||
60 | void __udelay(unsigned long usecs) | |
61 | { | |
62 | __const_udelay(usecs * 0x10C7UL); /* 2**32 / 1000000 (rounded up) */ | |
63 | } | |
64 | EXPORT_SYMBOL(__udelay); | |
65 | ||
66 | void __ndelay(unsigned long nsecs) | |
67 | { | |
68 | __const_udelay(nsecs * 0x5UL); /* 2**32 / 1000000000 (rounded up) */ | |
69 | } | |
70 | EXPORT_SYMBOL(__ndelay); |