1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
|
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*/
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/smp.h>
#include <linux/timex.h>
#include <asm/processor.h>
void __delay(unsigned long cycles)
{
u64 t0 = get_cycles();
while ((unsigned long)(get_cycles() - t0) < cycles)
cpu_relax();
}
EXPORT_SYMBOL(__delay);
/*
* Division by multiplication: you don't have to worry about
* loss of precision.
*
* Use only for very small delays ( < 1 msec). Should probably use a
* lookup table, really, as the multiplications take much too long with
* short delays. This is a "reasonable" implementation, though (and the
* first constant multiplications gets optimized away if the delay is
* a constant)
*/
void __udelay(unsigned long us)
{
__delay((us * 0x000010c7ull * HZ * lpj_fine) >> 32);
}
EXPORT_SYMBOL(__udelay);
void __ndelay(unsigned long ns)
{
__delay((ns * 0x00000005ull * HZ * lpj_fine) >> 32);
}
EXPORT_SYMBOL(__ndelay);
|
