1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * OpenRISC Linux
4 *
5 * Linux architectural port borrowing liberally from similar works of
6 * others. All original copyrights apply as per the original source
7 * declaration.
8 *
9 * Modifications for the OpenRISC architecture:
10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
11 *
12 * Precise Delay Loops
13 */
14
15 #include <linux/kernel.h>
16 #include <linux/export.h>
17 #include <linux/init.h>
18 #include <linux/timex.h>
19 #include <asm/param.h>
20 #include <asm/delay.h>
21 #include <asm/timex.h>
22 #include <asm/processor.h>
23
24 int read_current_timer(unsigned long *timer_value)
25 {
26 *timer_value = get_cycles();
27 return 0;
28 }
29
30 void __delay(unsigned long cycles)
31 {
32 cycles_t start = get_cycles();
33
34 while ((get_cycles() - start) < cycles)
35 cpu_relax();
36 }
37 EXPORT_SYMBOL(__delay);
38
39 inline void __const_udelay(unsigned long xloops)
40 {
41 unsigned long long loops;
42
43 loops = (unsigned long long)xloops * loops_per_jiffy * HZ;
44
45 __delay(loops >> 32);
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);
60
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