105 lines
3.7 KiB
C
105 lines
3.7 KiB
C
/****************************************************************************
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* arch/arm/src/kinetis/kinetis_wdog.c
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*
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* Copyright (C) 2011 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <nuttx/irq.h>
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#include "up_arch.h"
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#include "kinetis.h"
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#include "chip/kinetis_wdog.h"
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: kinetis_wdunlock
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*
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* Description:
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* Watchdog timer unlock routine. Writing 0xc520 followed by 0xd928 will
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* unlock the write once registers in the WDOG so they are writable
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* within the WCT period.
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*
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****************************************************************************/
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static void kinetis_wdunlock(void)
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{
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irqstate_t flags;
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/* This sequence must execute within 20 clock cycles. Disable interrupts
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* to assure that the following steps are atomic.
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*/
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flags = enter_critical_section();
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/* Write 0xC520 followed by 0xD928 to the unlock register */
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putreg16(0xc520, KINETIS_WDOG_UNLOCK);
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putreg16(0xd928, KINETIS_WDOG_UNLOCK);
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leave_critical_section(flags);
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: kinetis_wddisable
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*
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* Description:
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* Disable the watchdog timer
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*
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****************************************************************************/
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void kinetis_wddisable(void)
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{
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uint16_t regval;
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/* Unlock the watchdog so that we can write to registers */
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kinetis_wdunlock();
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/* Clear the WDOGEN bit to disable the watchdog */
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regval = getreg16(KINETIS_WDOG_STCTRLH);
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regval &= ~WDOG_STCTRLH_WDOGEN;
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putreg16(regval, KINETIS_WDOG_STCTRLH);
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}
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