75 lines
1.6 KiB
ArmAsm
75 lines
1.6 KiB
ArmAsm
/*
|
|
* Copyright (c) 2014 Wind River Systems, Inc.
|
|
*
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* @brief Watchdog initialization for fsl_frdm_k64f platform
|
|
*
|
|
* This module initializes the watchdog for the fsl_frdm_k64f platform.
|
|
*/
|
|
|
|
#include <soc.h>
|
|
#include <toolchain.h>
|
|
#include <linker/sections.h>
|
|
|
|
_ASM_FILE_PROLOGUE
|
|
|
|
GTEXT(z_arm_watchdog_init)
|
|
|
|
/* watchdog register offsets */
|
|
#define WDOG_SCTRL_HI_OFFSET 0x0
|
|
#define WDOG_UNLOCK_OFFSET 0xE
|
|
|
|
/* watchdog command words */
|
|
#define WDOG_UNLOCK_1_CMD 0xC520
|
|
#define WDOG_UNLOCK_2_CMD 0xD928
|
|
|
|
/**
|
|
*
|
|
* @brief Watchdog timer disable routine
|
|
*
|
|
* This routine will disable the watchdog timer.
|
|
*
|
|
* @return N/A
|
|
*/
|
|
|
|
SECTION_FUNC(TEXT,z_arm_watchdog_init)
|
|
/*
|
|
* NOTE: DO NOT SINGLE STEP THROUGH THIS FUNCTION!!!
|
|
* There are timing requirements for the execution of the unlock process.
|
|
* Single stepping through the code will cause the CPU to reset.
|
|
*/
|
|
|
|
/*
|
|
* First unlock the watchdog so that we can write to registers.
|
|
*
|
|
* This sequence must execute within 20 clock cycles, so disable
|
|
* interrupts to keep the code atomic and ensure the timing.
|
|
*/
|
|
|
|
ldr r0, =PERIPH_ADDR_BASE_WDOG
|
|
|
|
movw r1, #WDOG_UNLOCK_1_CMD
|
|
strh r1, [r0, #WDOG_UNLOCK_OFFSET]
|
|
|
|
movw r1, #WDOG_UNLOCK_2_CMD
|
|
strh r1, [r0, #WDOG_UNLOCK_OFFSET]
|
|
|
|
/*
|
|
* Disable the watchdog.
|
|
*
|
|
* Writes to control/configuration registers must execute within
|
|
* 256 clock cycles after unlocking.
|
|
*/
|
|
|
|
ldrh r1, [r0, #WDOG_SCTRL_HI_OFFSET]
|
|
mov r2, #1
|
|
bics r1, r2
|
|
strh r1, [r0, #WDOG_SCTRL_HI_OFFSET]
|
|
|
|
bx lr
|
|
|