1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2020 Loongson Technology Corporation Limited
4 */
5#include <linux/delay.h>
6#include <linux/export.h>
7#include <linux/smp.h>
8#include <linux/timex.h>
9
10#include <asm/processor.h>
11
12void __delay(unsigned long cycles)
13{
14	u64 t0 = get_cycles();
15
16	while ((unsigned long)(get_cycles() - t0) < cycles)
17		cpu_relax();
18}
19EXPORT_SYMBOL(__delay);
20
21/*
22 * Division by multiplication: you don't have to worry about
23 * loss of precision.
24 *
25 * Use only for very small delays ( < 1 msec).	Should probably use a
26 * lookup table, really, as the multiplications take much too long with
27 * short delays.  This is a "reasonable" implementation, though (and the
28 * first constant multiplications gets optimized away if the delay is
29 * a constant)
30 */
31
32void __udelay(unsigned long us)
33{
34	__delay((us * 0x000010c7ull * HZ * lpj_fine) >> 32);
35}
36EXPORT_SYMBOL(__udelay);
37
38void __ndelay(unsigned long ns)
39{
40	__delay((ns * 0x00000005ull * HZ * lpj_fine) >> 32);
41}
42EXPORT_SYMBOL(__ndelay);
43