Mbed OS Reference | watchdog

 /** \addtogroup hal */
 /** @{*/
 
 /*
  * Copyright (c) 2018-2019 Arm Limited and affiliates.
  * SPDX-License-Identifier: Apache-2.0
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 #ifndef MBED_WATCHDOG_API_H
 #define MBED_WATCHDOG_API_H
 
 #if DEVICE_WATCHDOG
 
 #include <stdbool.h>
 #include <stdint.h>
 
 /**
  * \defgroup hal_watchdog Watchdog HAL API
  * Low-level interface to the Independent Watchdog Timer of a target.
  *
  * This module provides platform independent access to the system watchdog timer
  * which is an embedded peripheral that will reset the system in the case of
  * system failures or malfunctions.
  *
  * The watchdog timer initializes a system timer with a time period specified in
  * the configuration. This timer counts down and triggers a system reset when it
  * wraps. To prevent the system reset the timer must be continually
  * kicked/refreshed by calling ::hal_watchdog_kick which will reset the countdown
  * to the user specified reset value.
  *
  * # Defined behavior
  * * Sleep and debug modes don't stop the watchdog timer from counting down.
  * * The function ::hal_watchdog_init is safe to call repeatedly. The
  * function's implementation must not do anything if ::hal_watchdog_init has
  * already initialized the hardware watchdog timer.
  * * Maximum supported timeout is `UINT32_MAX` milliseconds; minimum timeout
  * is 1 millisecond.
  * * The watchdog should trigger at or after the timeout value.
  * * The watchdog should trigger before twice the timeout value.
  *
  * # Undefined behavior
  * * Calling any function other than ::hal_watchdog_init or
  * ::hal_watchdog_get_platform_features before you have initialized the watchdog.
  *
  * # Notes
  * * A software reset may not stop the watchdog timer; the behavior is platform specific.
  *
  * @{
  */
 
 /**
  * \defgroup hal_watchdog_tests Watchdog HAL tests
  * Greentea tests for the Watchdog HAL.
  *
  * To run the Watchdog HAL tests use the command:
  *
  *     mbed test -t <toolchain> -m <target> -n tests-mbed_hal-watchdog*
  *
  */
 
 /** Watchdog configuration.
  */
 typedef struct {
     /**
     * Refresh value for the watchdog in milliseconds. The maximum value of this
     * setting is platform dependent, to find the maximum value for the current
     * platform call hal_watchdog_get_features() and check the timeout value
     * member. The minimum valid value for this setting is 1. Attempting to
     * initialize the watchdog with a timeout of 0 ms returns
     * WATCHDOG_STATUS_INVALID_ARGUMENT.
     */
     uint32_t timeout_ms;
 } watchdog_config_t;
 
 /** Watchdog features.
  */
 typedef struct {
     /**
      * Maximum timeout value for the watchdog in milliseconds.
      */
     uint32_t max_timeout;
     /**
      * You can update the watchdog configuration after the watchdog has started.
      */
     bool update_config;
     /**
      * You can stop the watchdog after it starts without a reset.
      */
     bool disable_watchdog;
 } watchdog_features_t;
 
 
 /** Status of a watchdog operation.
 */
 typedef enum {
     WATCHDOG_STATUS_OK,                 /**< Operation successful. **/
     WATCHDOG_STATUS_NOT_SUPPORTED,      /**< Operation not supported. **/
     WATCHDOG_STATUS_INVALID_ARGUMENT    /**< Invalid argument. **/
 } watchdog_status_t;
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /** Initialize and start a watchdog timer with the given configuration.
  *
  * If the watchdog timer is configured and starts successfully, this
  * function returns ::WATCHDOG_STATUS_OK.
  *
  * If the timeout specified is outside the range supported by the platform,
  * it returns ::WATCHDOG_STATUS_INVALID_ARGUMENT.
  *
  * @param[in]  config   Configuration settings for the watchdog timer
  *
  * @return ::WATCHDOG_STATUS_OK if the watchdog is configured correctly and
  *         has started. Otherwise a status indicating the fault.
  */
 watchdog_status_t hal_watchdog_init(const watchdog_config_t *config);
 
 /** Refreshes the watchdog timer.
  *
  * Call this function periodically before the watchdog times out.
  * Otherwise, the system resets.
  *
  * If a watchdog is not running, this function does nothing.
  */
 void hal_watchdog_kick(void);
 
 /** Stops the watchdog timer.
  *
  * Calling this function disables any running watchdog
  * timers if the current platform supports them.
  *
  * @return Returns ::WATCHDOG_STATUS_OK if the watchdog timer was succesfully
  *         stopped, or if the timer was never started. Returns
  *         ::WATCHDOG_STATUS_NOT_SUPPORTED if the watchdog cannot be disabled on
  *         the current platform.
  */
 watchdog_status_t hal_watchdog_stop(void);
 
 /** Get the watchdog timer refresh value.
  *
  * This function returns the configured refresh timeout of the watchdog timer.
  *
  * @return Reload value for the watchdog timer in milliseconds.
  */
 uint32_t hal_watchdog_get_reload_value(void);
 
 /** Get information on the current platforms supported watchdog functionality.
  *
  * @return watchdog_feature_t indicating supported watchdog features on the
  *         current platform
  */
 watchdog_features_t hal_watchdog_get_platform_features(void);
 
 /**@}*/
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif // DEVICE_WATCHDOG
 
 #endif // MBED_WATCHDOG_API_H
 
 /** @}*/
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