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#ifdef CONFIG_ARCH_RPC
12		.arch	armv4
13#endif
14
15		.text
16
17.LC0:		.word	loops_per_jiffy
18.LC1:		.word	UDELAY_MULT
19
20/*
21 * loops = r0 * HZ * loops_per_jiffy / 1000000
22 *
23 * r0  <= 2000
24 * HZ  <= 1000
25 */
26
27ENTRY(__loop_udelay)
28		ldr	r2, .LC1
29		mul	r0, r2, r0		@ r0 = delay_us * UDELAY_MULT
30ENTRY(__loop_const_udelay)			@ 0 <= r0 <= 0xfffffaf0
31		ldr	r2, .LC0
32		ldr	r2, [r2]
33		umull	r1, r0, r2, r0		@ r0-r1 = r0 * loops_per_jiffy
34		adds	r1, r1, #0xffffffff	@ rounding up ...
35		adcs	r0, r0, r0		@ and right shift by 31
36		reteq	lr
37
38		.align 3
39
40@ Delay routine
41ENTRY(__loop_delay)
42		subs	r0, r0, #1
43#if 0
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		retls	lr
55		subs	r0, r0, #1
56		retls	lr
57		subs	r0, r0, #1
58#endif
59		bhi	__loop_delay
60		ret	lr
61ENDPROC(__loop_udelay)
62ENDPROC(__loop_const_udelay)
63ENDPROC(__loop_delay)
64