diff options
Diffstat (limited to 'contrib/loaders/watchdog/armv7m_kinetis_wdog32.s')
| -rw-r--r-- | contrib/loaders/watchdog/armv7m_kinetis_wdog32.s | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/contrib/loaders/watchdog/armv7m_kinetis_wdog32.s b/contrib/loaders/watchdog/armv7m_kinetis_wdog32.s new file mode 100644 index 00000000..bf58327e --- /dev/null +++ b/contrib/loaders/watchdog/armv7m_kinetis_wdog32.s @@ -0,0 +1,81 @@ +/*************************************************************************** + * Copyright (C) 2017 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, 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 + |