riscv-openocd/contrib/loaders/watchdog/armv7m_kinetis_wdog.s

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/***************************************************************************
* Copyright (C) 2015 Tomas Vanek *
* vanekt@fbl.cz *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the *
* Free Software Foundation, Inc. *
***************************************************************************/
/*
Disable watchdog for Kinetis Kx and KVx
Parameters:
r0 ... WDOG base (in)
Used instruction set should work on both Cortex-M4 and M0+
*/
.text
.syntax unified
.cpu cortex-m0
.thumb
/* WDOG registers offsets */
WDOG_STCTRLH = 0
WDOG_UNLOCK = 0x0e
WDOG_KEY1 = 0xc520
WDOG_KEY2 = 0xd928
.thumb_func
start:
/* WDOG_UNLOCK = 0xC520 */
ldr r2, =WDOG_KEY1
strh r2, [r0, WDOG_UNLOCK]
/* WDOG_UNLOCK = 0xD928 */
ldr r2, =WDOG_KEY2
strh r2, [r0, WDOG_UNLOCK]
/* WDOG_STCTRLH clear bit 0 */
movs r4, #1
ldrh r2, [r0, WDOG_STCTRLH]
bics r2, r4
strh r2, [r0, WDOG_STCTRLH]
/* 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