1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 *  linux/arch/arm/lib/delay.S
4 *
5 *  Copyright (C) 1995, 1996 Russell King
6 */
7#include <linux/linkage.h>
8#include <asm/assembler.h>
9#include <asm/delay.h>
10
11		.text
12
13.LC0:		.word	loops_per_jiffy
14.LC1:		.word	UDELAY_MULT
15
16/*
17 * loops = r0 * HZ * loops_per_jiffy / 1000000
18 *
19 * r0  <= 2000
20 * HZ  <= 1000
21 */
22
23ENTRY(__loop_udelay)
24		ldr	r2, .LC1
25		mul	r0, r2, r0		@ r0 = delay_us * UDELAY_MULT
26ENTRY(__loop_const_udelay)			@ 0 <= r0 <= 0xfffffaf0
27		ldr	r2, .LC0
28		ldr	r2, [r2]
29		umull	r1, r0, r2, r0		@ r0-r1 = r0 * loops_per_jiffy
30		adds	r1, r1, #0xffffffff	@ rounding up ...
31		adcs	r0, r0, r0		@ and right shift by 31
32		reteq	lr
33
34		.align 3
35
36@ Delay routine
37ENTRY(__loop_delay)
38		subs	r0, r0, #1
39#if 0
40		retls	lr
41		subs	r0, r0, #1
42		retls	lr
43		subs	r0, r0, #1
44		retls	lr
45		subs	r0, r0, #1
46		retls	lr
47		subs	r0, r0, #1
48		retls	lr
49		subs	r0, r0, #1
50		retls	lr
51		subs	r0, r0, #1
52		retls	lr
53		subs	r0, r0, #1
54#endif
55		bhi	__loop_delay
56		ret	lr
57ENDPROC(__loop_udelay)
58ENDPROC(__loop_const_udelay)
59ENDPROC(__loop_delay)
60