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
24int read_current_timer(unsigned long *timer_value)
25{
26	*timer_value = get_cycles();
27	return 0;
28}
29
30void __delay(unsigned long cycles)
31{
32	cycles_t start = get_cycles();
33
34	while ((get_cycles() - start) < cycles)
35		cpu_relax();
36}
37EXPORT_SYMBOL(__delay);
38
39inline 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}
47EXPORT_SYMBOL(__const_udelay);
48
49void __udelay(unsigned long usecs)
50{
51	__const_udelay(usecs * 0x10C7UL); /* 2**32 / 1000000 (rounded up) */
52}
53EXPORT_SYMBOL(__udelay);
54
55void __ndelay(unsigned long nsecs)
56{
57	__const_udelay(nsecs * 0x5UL); /* 2**32 / 1000000000 (rounded up) */
58}
59EXPORT_SYMBOL(__ndelay);
60