1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2011 Richard Weinberger <richrd@nod.at>
4 * Mostly copied from arch/x86/lib/delay.c
5 */
6
7 #include <linux/export.h>
8 #include <linux/kernel.h>
9 #include <linux/delay.h>
10 #include <asm/param.h>
11
12 void __delay(unsigned long loops)
13 {
14 asm volatile(
15 "test %0,%0\n"
16 "jz 3f\n"
17 "jmp 1f\n"
18
19 ".align 16\n"
20 "1: jmp 2f\n"
21
22 ".align 16\n"
23 "2: dec %0\n"
24 " jnz 2b\n"
25 "3: dec %0\n"
26
27 : /* we don't need output */
28 : "a" (loops)
29 );
30 }
31 EXPORT_SYMBOL(__delay);
32
33 inline void __const_udelay(unsigned long xloops)
34 {
35 int d0;
36
37 xloops *= 4;
38 asm("mull %%edx"
39 : "=d" (xloops), "=&a" (d0)
40 : "1" (xloops), ""
41 (loops_per_jiffy * (HZ/4)));
42
43 __delay(++xloops);
44 }
45 EXPORT_SYMBOL(__const_udelay);
46
47 void __udelay(unsigned long usecs)
48 {
49 __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
50 }
51 EXPORT_SYMBOL(__udelay);
52
53 void __ndelay(unsigned long nsecs)
54 {
55 __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
56 }
57 EXPORT_SYMBOL(__ndelay);
58
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