Denislam Valeev / Mbed OS Nucleo_rtos_basic

1

mbed-os/hal/critical_section_api.h@0:e056ac8fecf8, 2018-03-13 (annotated)

Committer:
valeyev
Date:
Tue Mar 13 07:17:50 2018 +0000
Revision:
0:e056ac8fecf8
looking for...

Who changed what in which revision?

UserRevisionLine numberNew contents of line
valeyev 0:e056ac8fecf8 1 /** \addtogroup hal */
valeyev 0:e056ac8fecf8 2 /** @{*/
valeyev 0:e056ac8fecf8 3 /* mbed Microcontroller Library
valeyev 0:e056ac8fecf8 4 * Copyright (c) 2006-2017 ARM Limited
valeyev 0:e056ac8fecf8 5 *
valeyev 0:e056ac8fecf8 6 * Licensed under the Apache License, Version 2.0 (the "License");
valeyev 0:e056ac8fecf8 7 * you may not use this file except in compliance with the License.
valeyev 0:e056ac8fecf8 8 * You may obtain a copy of the License at
valeyev 0:e056ac8fecf8 9 *
valeyev 0:e056ac8fecf8 10 * http://www.apache.org/licenses/LICENSE-2.0
valeyev 0:e056ac8fecf8 11 *
valeyev 0:e056ac8fecf8 12 * Unless required by applicable law or agreed to in writing, software
valeyev 0:e056ac8fecf8 13 * distributed under the License is distributed on an "AS IS" BASIS,
valeyev 0:e056ac8fecf8 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
valeyev 0:e056ac8fecf8 15 * See the License for the specific language governing permissions and
valeyev 0:e056ac8fecf8 16 * limitations under the License.
valeyev 0:e056ac8fecf8 17 */
valeyev 0:e056ac8fecf8 18 #ifndef MBED_CRITICAL_SECTION_API_H
valeyev 0:e056ac8fecf8 19 #define MBED_CRITICAL_SECTION_API_H
valeyev 0:e056ac8fecf8 20
valeyev 0:e056ac8fecf8 21 #include <stdbool.h>
valeyev 0:e056ac8fecf8 22
valeyev 0:e056ac8fecf8 23 #ifdef __cplusplus
valeyev 0:e056ac8fecf8 24 extern "C" {
valeyev 0:e056ac8fecf8 25 #endif
valeyev 0:e056ac8fecf8 26
valeyev 0:e056ac8fecf8 27 /**
valeyev 0:e056ac8fecf8 28 * \defgroup hal_critical Critical Section HAL functions
valeyev 0:e056ac8fecf8 29 * @{
valeyev 0:e056ac8fecf8 30 */
valeyev 0:e056ac8fecf8 31
valeyev 0:e056ac8fecf8 32 /**
valeyev 0:e056ac8fecf8 33 * Mark the start of a critical section
valeyev 0:e056ac8fecf8 34 *
valeyev 0:e056ac8fecf8 35 * This function will be called by core_util_critical_section_enter() each time
valeyev 0:e056ac8fecf8 36 * the application requests to enter a critical section. The purpose of the
valeyev 0:e056ac8fecf8 37 * critical section is to ensure mutual-exclusion synchronisation of the
valeyev 0:e056ac8fecf8 38 * processor by preventing any change in processor control, the default
valeyev 0:e056ac8fecf8 39 * behaviour requires storing the state of interrupts in the system before
valeyev 0:e056ac8fecf8 40 * disabling them.
valeyev 0:e056ac8fecf8 41 *
valeyev 0:e056ac8fecf8 42 * The critical section code supports nesting. When a thread has entered a
valeyev 0:e056ac8fecf8 43 * critical section it can make additional calls to
valeyev 0:e056ac8fecf8 44 * core_util_critical_section_enter() without deadlocking itself. The critical
valeyev 0:e056ac8fecf8 45 * section driver API tracks the number of nested calls to the critical section.
valeyev 0:e056ac8fecf8 46 * The critical section will only be exited when
valeyev 0:e056ac8fecf8 47 * core_util_critical_section_exit() has been called once for each time it
valeyev 0:e056ac8fecf8 48 * entered the critical section.
valeyev 0:e056ac8fecf8 49 *
valeyev 0:e056ac8fecf8 50 * On the first call to enter a critical section this function MUST store the
valeyev 0:e056ac8fecf8 51 * state of any interrupts or other application settings it will modify to
valeyev 0:e056ac8fecf8 52 * facilitate the critical section.
valeyev 0:e056ac8fecf8 53 *
valeyev 0:e056ac8fecf8 54 * Each successive call to enter the critical section MUST ignore storing or
valeyev 0:e056ac8fecf8 55 * modifying any application state.
valeyev 0:e056ac8fecf8 56 *
valeyev 0:e056ac8fecf8 57 * The default implementation of this function which will save the current state
valeyev 0:e056ac8fecf8 58 * of interrupts before disabling them. This implementation can be found in
valeyev 0:e056ac8fecf8 59 * mbed_critical_section_api.c. This behaviour is can be overridden on a per
valeyev 0:e056ac8fecf8 60 * platform basis by providing a different implementation within the correct
valeyev 0:e056ac8fecf8 61 * targets directory.
valeyev 0:e056ac8fecf8 62 */
valeyev 0:e056ac8fecf8 63 void hal_critical_section_enter(void);
valeyev 0:e056ac8fecf8 64
valeyev 0:e056ac8fecf8 65
valeyev 0:e056ac8fecf8 66 /** Mark the end of a critical section.
valeyev 0:e056ac8fecf8 67 *
valeyev 0:e056ac8fecf8 68 * The purpose of this function is to restore any state that was modified upon
valeyev 0:e056ac8fecf8 69 * entering the critical section, allowing other threads or interrupts to change
valeyev 0:e056ac8fecf8 70 * the processor control.
valeyev 0:e056ac8fecf8 71 *
valeyev 0:e056ac8fecf8 72 * This function will be called once by core_util_critical_section_exit() per
valeyev 0:e056ac8fecf8 73 * critical section on last call to exit. When called, the application MUST
valeyev 0:e056ac8fecf8 74 * restore the saved interrupt/application state that was saved when entering
valeyev 0:e056ac8fecf8 75 * the critical section.
valeyev 0:e056ac8fecf8 76 *
valeyev 0:e056ac8fecf8 77 * There is a default implementation of this function, it will restore the state
valeyev 0:e056ac8fecf8 78 * of interrupts that were previously saved when hal_critical_section_enter was
valeyev 0:e056ac8fecf8 79 * first called, this implementation can be found in
valeyev 0:e056ac8fecf8 80 * mbed_critical_section_api.c. This behaviour is overridable by providing a
valeyev 0:e056ac8fecf8 81 * different function implementation within the correct targets directory.
valeyev 0:e056ac8fecf8 82 */
valeyev 0:e056ac8fecf8 83 void hal_critical_section_exit(void);
valeyev 0:e056ac8fecf8 84
valeyev 0:e056ac8fecf8 85
valeyev 0:e056ac8fecf8 86 /** Determine if the application is currently running in a critical section
valeyev 0:e056ac8fecf8 87 *
valeyev 0:e056ac8fecf8 88 * The purpose of this function is to inform the caller whether or not the
valeyev 0:e056ac8fecf8 89 * application is running in a critical section. This is done by checking if
valeyev 0:e056ac8fecf8 90 * the current interrupt state has been saved in the underlying implementation,
valeyev 0:e056ac8fecf8 91 * this could also be done by checking the state of the interrupts at the time
valeyev 0:e056ac8fecf8 92 * of calling.
valeyev 0:e056ac8fecf8 93 *
valeyev 0:e056ac8fecf8 94 * @return True if running in a critical section, false if not.
valeyev 0:e056ac8fecf8 95 */
valeyev 0:e056ac8fecf8 96 bool hal_in_critical_section(void);
valeyev 0:e056ac8fecf8 97
valeyev 0:e056ac8fecf8 98
valeyev 0:e056ac8fecf8 99 /**@}*/
valeyev 0:e056ac8fecf8 100
valeyev 0:e056ac8fecf8 101 #ifdef __cplusplus
valeyev 0:e056ac8fecf8 102 }
valeyev 0:e056ac8fecf8 103 #endif
valeyev 0:e056ac8fecf8 104
valeyev 0:e056ac8fecf8 105 #endif // MBED_CRITICAL_SECTION_API_H
valeyev 0:e056ac8fecf8 106
valeyev 0:e056ac8fecf8 107 /** @}*/