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 
__delay(unsigned long loops)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 
__const_udelay(unsigned long xloops)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), "0"
41 		(loops_per_jiffy * (HZ/4)));
42 
43 	__delay(++xloops);
44 }
45 EXPORT_SYMBOL(__const_udelay);
46 
__udelay(unsigned long usecs)47 void __udelay(unsigned long usecs)
48 {
49 	__const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
50 }
51 EXPORT_SYMBOL(__udelay);
52 
__ndelay(unsigned long nsecs)53 void __ndelay(unsigned long nsecs)
54 {
55 	__const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
56 }
57 EXPORT_SYMBOL(__ndelay);
58