162306a36Sopenharmony_ci/* SPDX-License-Identifier: GPL-2.0-only */ 262306a36Sopenharmony_ci/* 362306a36Sopenharmony_ci * linux/arch/arm/lib/delay.S 462306a36Sopenharmony_ci * 562306a36Sopenharmony_ci * Copyright (C) 1995, 1996 Russell King 662306a36Sopenharmony_ci */ 762306a36Sopenharmony_ci#include <linux/linkage.h> 862306a36Sopenharmony_ci#include <asm/assembler.h> 962306a36Sopenharmony_ci#include <asm/delay.h> 1062306a36Sopenharmony_ci 1162306a36Sopenharmony_ci#ifdef CONFIG_ARCH_RPC 1262306a36Sopenharmony_ci .arch armv4 1362306a36Sopenharmony_ci#endif 1462306a36Sopenharmony_ci 1562306a36Sopenharmony_ci .text 1662306a36Sopenharmony_ci 1762306a36Sopenharmony_ci.LC0: .word loops_per_jiffy 1862306a36Sopenharmony_ci.LC1: .word UDELAY_MULT 1962306a36Sopenharmony_ci 2062306a36Sopenharmony_ci/* 2162306a36Sopenharmony_ci * loops = r0 * HZ * loops_per_jiffy / 1000000 2262306a36Sopenharmony_ci * 2362306a36Sopenharmony_ci * r0 <= 2000 2462306a36Sopenharmony_ci * HZ <= 1000 2562306a36Sopenharmony_ci */ 2662306a36Sopenharmony_ci 2762306a36Sopenharmony_ciENTRY(__loop_udelay) 2862306a36Sopenharmony_ci ldr r2, .LC1 2962306a36Sopenharmony_ci mul r0, r2, r0 @ r0 = delay_us * UDELAY_MULT 3062306a36Sopenharmony_ciENTRY(__loop_const_udelay) @ 0 <= r0 <= 0xfffffaf0 3162306a36Sopenharmony_ci ldr r2, .LC0 3262306a36Sopenharmony_ci ldr r2, [r2] 3362306a36Sopenharmony_ci umull r1, r0, r2, r0 @ r0-r1 = r0 * loops_per_jiffy 3462306a36Sopenharmony_ci adds r1, r1, #0xffffffff @ rounding up ... 3562306a36Sopenharmony_ci adcs r0, r0, r0 @ and right shift by 31 3662306a36Sopenharmony_ci reteq lr 3762306a36Sopenharmony_ci 3862306a36Sopenharmony_ci .align 3 3962306a36Sopenharmony_ci 4062306a36Sopenharmony_ci@ Delay routine 4162306a36Sopenharmony_ciENTRY(__loop_delay) 4262306a36Sopenharmony_ci subs r0, r0, #1 4362306a36Sopenharmony_ci#if 0 4462306a36Sopenharmony_ci retls lr 4562306a36Sopenharmony_ci subs r0, r0, #1 4662306a36Sopenharmony_ci retls lr 4762306a36Sopenharmony_ci subs r0, r0, #1 4862306a36Sopenharmony_ci retls lr 4962306a36Sopenharmony_ci subs r0, r0, #1 5062306a36Sopenharmony_ci retls lr 5162306a36Sopenharmony_ci subs r0, r0, #1 5262306a36Sopenharmony_ci retls lr 5362306a36Sopenharmony_ci subs r0, r0, #1 5462306a36Sopenharmony_ci retls lr 5562306a36Sopenharmony_ci subs r0, r0, #1 5662306a36Sopenharmony_ci retls lr 5762306a36Sopenharmony_ci subs r0, r0, #1 5862306a36Sopenharmony_ci#endif 5962306a36Sopenharmony_ci bhi __loop_delay 6062306a36Sopenharmony_ci ret lr 6162306a36Sopenharmony_ciENDPROC(__loop_udelay) 6262306a36Sopenharmony_ciENDPROC(__loop_const_udelay) 6362306a36Sopenharmony_ciENDPROC(__loop_delay) 64