mirror of https://github.com/ARMmbed/mbed-os.git
108 lines
3.9 KiB
C
108 lines
3.9 KiB
C
/** \addtogroup hal */
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/** @{*/
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/* mbed Microcontroller Library
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* Copyright (c) 2006-2017 ARM Limited
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* 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,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef MBED_CRITICAL_SECTION_API_H
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#define MBED_CRITICAL_SECTION_API_H
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#include <stdbool.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* \defgroup hal_critical Critical Section HAL functions
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* @{
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*/
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/**
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* Mark the start of a critical section
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*
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* This function will be called by core_util_critical_section_enter() each time
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* the application requests to enter a critical section. The purpose of the
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* critical section is to ensure mutual-exclusion synchronisation of the
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* processor by preventing any change in processor control, the default
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* behaviour requires storing the state of interrupts in the system before
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* disabling them.
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*
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* The critical section code supports nesting. When a thread has entered a
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* critical section it can make additional calls to
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* core_util_critical_section_enter() without deadlocking itself. The critical
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* section driver API tracks the number of nested calls to the critical section.
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* The critical section will only be exited when
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* core_util_critical_section_exit() has been called once for each time it
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* entered the critical section.
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*
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* On the first call to enter a critical section this function MUST store the
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* state of any interrupts or other application settings it will modify to
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* facilitate the critical section.
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*
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* Each successive call to enter the critical section MUST ignore storing or
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* modifying any application state.
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*
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* The default implementation of this function which will save the current state
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* of interrupts before disabling them. This implementation can be found in
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* mbed_critical_section_api.c. This behaviour is can be overridden on a per
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* platform basis by providing a different implementation within the correct
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* targets directory.
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*/
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void hal_critical_section_enter(void);
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/** Mark the end of a critical section.
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*
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* The purpose of this function is to restore any state that was modified upon
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* entering the critical section, allowing other threads or interrupts to change
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* the processor control.
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*
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* This function will be called once by core_util_critical_section_exit() per
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* critical section on last call to exit. When called, the application MUST
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* restore the saved interrupt/application state that was saved when entering
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* the critical section.
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*
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* There is a default implementation of this function, it will restore the state
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* of interrupts that were previously saved when hal_critical_section_enter was
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* first called, this implementation can be found in
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* mbed_critical_section_api.c. This behaviour is overridable by providing a
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* different function implementation within the correct targets directory.
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*/
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void hal_critical_section_exit(void);
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/** Determine if the application is currently running in a critical section
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*
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* The purpose of this function is to inform the caller whether or not the
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* application is running in a critical section. This is done by checking if
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* the current interrupt state has been saved in the underlying implementation,
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* this could also be done by checking the state of the interrupts at the time
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* of calling.
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*
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* @return True if running in a critical section, false if not.
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*/
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bool hal_in_critical_section(void);
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/**@}*/
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#ifdef __cplusplus
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}
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#endif
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#endif // MBED_CRITICAL_SECTION_API_H
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/** @}*/
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