| /* SPDX-License-Identifier: GPL-2.0-only */ |
| /* |
| * linux/arch/arm/lib/delay.S |
| * |
| * Copyright (C) 1995, 1996 Russell King |
| */ |
| #include <linux/linkage.h> |
| #include <asm/assembler.h> |
| #include <asm/delay.h> |
| |
| .text |
| |
| .LC0: .word loops_per_jiffy |
| .LC1: .word UDELAY_MULT |
| |
| /* |
| * loops = r0 * HZ * loops_per_jiffy / 1000000 |
| * |
| * r0 <= 2000 |
| * HZ <= 1000 |
| */ |
| |
| ENTRY(__loop_udelay) |
| ldr r2, .LC1 |
| mul r0, r2, r0 @ r0 = delay_us * UDELAY_MULT |
| ENTRY(__loop_const_udelay) @ 0 <= r0 <= 0xfffffaf0 |
| ldr r2, .LC0 |
| ldr r2, [r2] |
| umull r1, r0, r2, r0 @ r0-r1 = r0 * loops_per_jiffy |
| adds r1, r1, #0xffffffff @ rounding up ... |
| adcs r0, r0, r0 @ and right shift by 31 |
| reteq lr |
| |
| .align 3 |
| |
| @ Delay routine |
| ENTRY(__loop_delay) |
| subs r0, r0, #1 |
| #if 0 |
| retls lr |
| subs r0, r0, #1 |
| retls lr |
| subs r0, r0, #1 |
| retls lr |
| subs r0, r0, #1 |
| retls lr |
| subs r0, r0, #1 |
| retls lr |
| subs r0, r0, #1 |
| retls lr |
| subs r0, r0, #1 |
| retls lr |
| subs r0, r0, #1 |
| #endif |
| bhi __loop_delay |
| ret lr |
| ENDPROC(__loop_udelay) |
| ENDPROC(__loop_const_udelay) |
| ENDPROC(__loop_delay) |
