/* * Copyright (c) 2018 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_H #define MBED_WATCHDOG_H #ifdef DEVICE_WATCHDOG #include "platform/mbed_error.h" #include "platform/mbed_assert.h" #include "platform/mbed_critical.h" #include "hal/watchdog_api.h" #include "platform/NonCopyable.h" #include <cstdio> namespace mbed { /** \addtogroup drivers */ /** Hardware system timer that will reset the system in the case of system failures or * malfunctions. There is only one instance in the system. * * Example: * @code * * Watchdog &watchdog = Watchdog::get_instance(); * watchdog.start(); * * while (true) { // kick watchdog regularly within provided timeout watchdog.kick(); // Application code * } * @endcode * * @note Synchronization level: Interrupt safe * @ingroup drivers */ class Watchdog : private NonCopyable<Watchdog> { public: /** As Watchdog might not stop ever, there is just one instance - we use single instance. * This ensures we keep Watchdog alive. To operate watchdog, use start/stop methods. */ static Watchdog &get_instance() { // Use this implementation of singleton (Meyer's) rather than the one that allocates // the instance on the heap because it ensures destruction at program end (preventing warnings // from memory checking tools, such as valgrind). static Watchdog instance; return instance; } /** Start the watchdog timer with the maximum timeout available on a target * * Timeout is defined as get_max_timeout() * * @return status true if the watchdog timer was started * successfully. assert if one of the input parameters is out of range for the current platform. * false if watchdog timer was not started */ bool start(); /** Start the watchdog timer * * @param timeout Watchdog timeout * * @return status true if the watchdog timer was started * successfully. assert if one of the input parameters is out of range for the current platform. * false if watchdog timer was not started */ bool start(uint32_t timeout); /** Stops the watchdog timer * * Calling this function will attempt to disable any currently running * watchdog timers if supported by the current platform. * * @return Returns true if the watchdog timer was successfully * stopped, Returns false if the watchdog cannot be disabled * on the current platform or if the timer was never started. */ bool stop(); /** Get the watchdog timer refresh value * * This function returns the refresh timeout of the watchdog timer. * * @return Reload value for the watchdog timer in milliseconds. */ uint32_t get_timeout() const; /** Get the maximum refresh value for the current platform in milliseconds * * @return Maximum refresh value supported by the watchdog for the current * platform in milliseconds */ uint32_t get_max_timeout() const; /** Check if watchdog is already running * * @return true if watchdog is running, false otherwise */ bool is_running() const; /** Kick watchdog * * This method is useful to control kicking by application in ticker callback periodically */ void kick(); private: Watchdog(); ~Watchdog(); bool _running; }; } // namespace mbed #endif // DEVICE_WATCHDOG #endif // MBED_WATCHDOG_H