359 lines
11 KiB
C
359 lines
11 KiB
C
/****************************************************************************
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* arch/arm/src/lpc17xx_40xx/lpc17_40_wdt.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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/arch.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include <assert.h>
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#include <errno.h>
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#include <nuttx/timers/watchdog.h>
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#include <arch/board/board.h>
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#include <nuttx/clock.h>
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#include "chip.h"
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#include "arm_internal.h"
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#include "hardware/lpc17_40_wdt.h"
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#include "hardware/lpc17_40_syscon.h"
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#include "lpc17_40_wdt.h"
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#if defined(CONFIG_WATCHDOG) && defined(CONFIG_LPC17_40_WDT)
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Default WDT timeout value, in ms. */
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#define LPC17_40_WDT_DEFTIMEOUT 1000
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/****************************************************************************
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* Private Types
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****************************************************************************/
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/* This structure provides the private representation of the "lower-half"
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* driver state structure. This structure must be cast-compatible with the
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* well-known watchdog_lowerhalf_s structure.
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*/
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struct lpc17_40_lowerhalf_s
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{
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FAR const struct watchdog_ops_s *ops; /* Lower half operations */
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uint32_t timeout; /* The (actual) selected timeout */
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uint32_t lastreset; /* The last reset time */
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bool started; /* true: The watchdog timer has been started */
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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/* "Lower half" driver methods **********************************************/
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static int lpc17_40_start(FAR struct watchdog_lowerhalf_s *lower);
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static int lpc17_40_stop(FAR struct watchdog_lowerhalf_s *lower);
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static int lpc17_40_keepalive(FAR struct watchdog_lowerhalf_s *lower);
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static int lpc17_40_getstatus(FAR struct watchdog_lowerhalf_s *lower,
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FAR struct watchdog_status_s *status);
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static int lpc17_40_settimeout(FAR struct watchdog_lowerhalf_s *lower,
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uint32_t timeout);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/* "Lower half" driver methods */
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static const struct watchdog_ops_s g_wdgops =
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{
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.start = lpc17_40_start,
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.stop = lpc17_40_stop,
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.keepalive = lpc17_40_keepalive,
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.getstatus = lpc17_40_getstatus,
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.settimeout = lpc17_40_settimeout,
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.capture = NULL,
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.ioctl = NULL,
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};
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/* "Lower half" driver state */
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static struct lpc17_40_lowerhalf_s g_wdgdev;
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: lpc17_40_start
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*
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* Description:
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* Start the watchdog timer, resetting the time to the current timeout.
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*
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* Input Parameters:
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* lower - A pointer to the publicly visible representation of the
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* "lower-half" driver state structure.
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*
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* Returned Value:
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* Zero on success; a negated errno value on failure.
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*
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****************************************************************************/
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static int lpc17_40_start(FAR struct watchdog_lowerhalf_s *lower)
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{
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FAR struct lpc17_40_lowerhalf_s *priv =
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(FAR struct lpc17_40_lowerhalf_s *)lower;
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irqstate_t flags;
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uint32_t wdmod;
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DEBUGASSERT(priv);
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/* Have we already been started? */
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if (!priv->started)
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{
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flags = enter_critical_section();
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priv->started = true;
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priv->lastreset = clock_systime_ticks();
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wdmod = getreg32(LPC17_40_WDT_MOD);
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wdmod |= (WDT_MOD_WDEN | WDT_MOD_WDRESET);
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putreg32(wdmod, LPC17_40_WDT_MOD);
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putreg32(WDT_FEED_KEY_1, LPC17_40_WDT_FEED);
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putreg32(WDT_FEED_KEY_2, LPC17_40_WDT_FEED);
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leave_critical_section(flags);
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}
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return OK;
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}
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/****************************************************************************
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* Name: lpc17_40_stop
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*
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* Description:
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* Stop the watchdog timer.
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*
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* Input Parameters:
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* lower - A pointer to the publicly visible representation of the
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* "lower-half" driver state structure.
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*
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* Returned Value:
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* Zero on success; a negated errno value on failure.
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*
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****************************************************************************/
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static int lpc17_40_stop(FAR struct watchdog_lowerhalf_s *lower)
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{
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/* There is no way to disable WDT once it has been started. */
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return -ENOSYS;
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}
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/****************************************************************************
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* Name: lpc17_40_keepalive
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*
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* Description:
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* Reset the watchdog timer to the current timeout value, prevent any
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* imminent watchdog timeouts. This is sometimes referred as "pinging"
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* the watchdog timer or "petting the dog".
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*
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* Input Parameters:
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* lower - A pointer the publicly visible representation of the
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* "lower-half" driver state structure.
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*
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* Returned Value:
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* Zero on success; a negated errno value on failure.
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*
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****************************************************************************/
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static int lpc17_40_keepalive(FAR struct watchdog_lowerhalf_s *lower)
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{
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FAR struct lpc17_40_lowerhalf_s *priv =
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(FAR struct lpc17_40_lowerhalf_s *)lower;
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irqstate_t flags;
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/* Reload the WDT. */
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flags = enter_critical_section();
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putreg32(WDT_FEED_KEY_1, LPC17_40_WDT_FEED);
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putreg32(WDT_FEED_KEY_2, LPC17_40_WDT_FEED);
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priv->lastreset = clock_systime_ticks();
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leave_critical_section(flags);
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return OK;
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}
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/****************************************************************************
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* Name: lpc17_40_getstatus
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*
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* Description:
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* Get the current watchdog timer status.
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*
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* Input Parameters:
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* lower - A pointer to the publicly visible representation of the
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* "lower-half" driver state structure.
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* status - The location to return the watchdog status information.
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*
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* Returned Value:
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* Zero on success; a negated errno value on failure.
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*
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****************************************************************************/
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static int lpc17_40_getstatus(FAR struct watchdog_lowerhalf_s *lower,
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FAR struct watchdog_status_s *status)
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{
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FAR struct lpc17_40_lowerhalf_s *priv =
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(FAR struct lpc17_40_lowerhalf_s *)lower;
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uint32_t ticks;
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uint32_t elapsed;
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DEBUGASSERT(priv);
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/* Return the status bit. */
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status->flags = WDFLAGS_RESET;
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if (priv->started)
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{
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status->flags |= WDFLAGS_ACTIVE;
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}
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/* Return the actual timeout in milliseconds. */
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status->timeout = priv->timeout;
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/* Get the elapsed time since the last ping. */
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ticks = clock_systime_ticks() - priv->lastreset;
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elapsed = (int32_t)TICK2MSEC(ticks);
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if (elapsed > priv->timeout)
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{
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elapsed = priv->timeout;
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}
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/* Return the approximate time until the watchdog timer expiration. */
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status->timeleft = priv->timeout - elapsed;
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return OK;
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}
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/****************************************************************************
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* Name: lpc17_40_settimeout
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*
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* Description:
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* Set a new timeout value.
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*
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* Input Parameters:
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* lower - A pointer to the publicly visible representation of the
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* "lower-half" driver state structure.
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* timeout - The new timeout value in milliseconds.
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*
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* Returned Value:
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* Zero on success; a negated errno value on failure.
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*
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****************************************************************************/
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static int lpc17_40_settimeout(FAR struct watchdog_lowerhalf_s *lower,
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uint32_t timeout)
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{
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FAR struct lpc17_40_lowerhalf_s *priv =
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(FAR struct lpc17_40_lowerhalf_s *)lower;
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uint64_t wdt_clk;
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uint64_t wdtc;
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priv->timeout = timeout;
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#ifdef LPC176x
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/* The internal RC oscillator will be used for the WDT. It is clocked at
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* 4MHz. This is further divided by 4, by the WDT fixed prescaller.
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*/
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wdt_clk = 4000000 / 4;
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putreg32(WDT_CLKSEL_WDSEL_INTRC, LPC17_40_WDT_CLKSEL);
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#else
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/* WDT has a dedicated clock, set at 500kHz. This is further divided by 4,
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* by the WDT fixed prescaller.
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*/
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wdt_clk = 500000 / 4;
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#endif
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wdtc = ((uint64_t)timeout * wdt_clk) / 1000;
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putreg32((uint32_t)wdtc, LPC17_40_WDT_TC);
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return OK;
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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: lpc17_40_wdtinitialize
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*
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* Description:
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* Initialize the watchdog timer. The watchdog timer is initialized and
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* registers as 'devpath. The initial state of the watchdog timer is
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* disabled.
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*
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* Input Parameters:
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* devpath - The full path to the watchdog. This should be of the form
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* /dev/watchdog0
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void lpc17_40_wdtinitialize(FAR const char *devpath)
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{
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FAR struct lpc17_40_lowerhalf_s *priv = &g_wdgdev;
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/* Initialize the driver state structure. */
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priv->ops = &g_wdgops;
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priv->timeout = 0;
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priv->lastreset = 0;
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priv->started = false;
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/* Select an arbitrary initial timeout value. But don't start the watchdog
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* yet.
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*/
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lpc17_40_settimeout((FAR struct watchdog_lowerhalf_s *)priv,
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LPC17_40_WDT_DEFTIMEOUT);
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/* Register the watchdog driver as devpath. */
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watchdog_register(devpath, (FAR struct watchdog_lowerhalf_s *)priv);
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}
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#endif /* CONFIG_WATCHDOG && CONFIG_LPC17_40_WDT */
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