69 lines
1.5 KiB
ArmAsm
69 lines
1.5 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-or-later */
|
|
|
|
/***************************************************************************
|
|
* Copyright (C) 2017 Tomas Vanek *
|
|
* vanekt@fbl.cz *
|
|
***************************************************************************/
|
|
|
|
/*
|
|
Disable watchdog, 32-bit version for newer Kinetis
|
|
Parameters:
|
|
r0 ... WDOG32 base (in)
|
|
|
|
Used instruction set should work on both Cortex-M4 and M0+
|
|
*/
|
|
|
|
.text
|
|
.syntax unified
|
|
.cpu cortex-m0
|
|
.thumb
|
|
|
|
/* WDOG registers offsets */
|
|
WDOG_CS = 0
|
|
WDOG_CNT = 4
|
|
WDOG_TOVAL = 8
|
|
|
|
WDOG_KEY = 0xd928c520
|
|
|
|
.thumb_func
|
|
start:
|
|
/* test WDOG_CS bit CMD32EN */
|
|
ldr r2, [r0, WDOG_CS]
|
|
ldr r3, =0x2000
|
|
tst r2, r3
|
|
ldr r3, =WDOG_KEY
|
|
beq cmd16
|
|
|
|
/* WDOG_CNT = key */
|
|
str r3, [r0, WDOG_CNT]
|
|
b unlocked
|
|
|
|
cmd16:
|
|
/* WDOG_CNT = key, halfword by halfword */
|
|
strh r3, [r0, WDOG_CNT]
|
|
lsrs r3, r3, #16
|
|
strh r3, [r0, WDOG_CNT]
|
|
|
|
/* WDOG_CS: clear EN bit 7, set UPDATE bit 5 */
|
|
unlocked:
|
|
movs r4, #0x80
|
|
bics r2, r4
|
|
movs r4, #0x20
|
|
orrs r2, r4
|
|
str r2, [r0, WDOG_CS]
|
|
/* All active WDOG registers have to be updated, set dummy timeout */
|
|
/* WDOG_TOVAL = 0x400 */
|
|
ldr r3, =0x400
|
|
str r3, [r0, WDOG_TOVAL]
|
|
/* OpenOCD checks exit point address. Jump to the very end. */
|
|
b done
|
|
|
|
.pool
|
|
|
|
/* Avoid padding at .text segment end. Otherwise exit point check fails. */
|
|
.skip ( . - start + 2) & 2, 0
|
|
done:
|
|
bkpt #0
|
|
|
|
.end
|