BA / Mbed OS BaBoRo_test2

Backup 1

mbed-os/hal/critical_section_api.h@0:02dd72d1d465, 2018-04-24 (annotated)

Committer:
borlanic
Date:
Tue Apr 24 11:45:18 2018 +0000
Revision:
0:02dd72d1d465
BaBoRo_test2 - backup 1

Who changed what in which revision?

UserRevisionLine numberNew contents of line
borlanic 0:02dd72d1d465 1 /** \addtogroup hal */
borlanic 0:02dd72d1d465 2 /** @{*/
borlanic 0:02dd72d1d465 3 /* mbed Microcontroller Library
borlanic 0:02dd72d1d465 4 * Copyright (c) 2006-2017 ARM Limited
borlanic 0:02dd72d1d465 5 *
borlanic 0:02dd72d1d465 6 * Licensed under the Apache License, Version 2.0 (the "License");
borlanic 0:02dd72d1d465 7 * you may not use this file except in compliance with the License.
borlanic 0:02dd72d1d465 8 * You may obtain a copy of the License at
borlanic 0:02dd72d1d465 9 *
borlanic 0:02dd72d1d465 10 * http://www.apache.org/licenses/LICENSE-2.0
borlanic 0:02dd72d1d465 11 *
borlanic 0:02dd72d1d465 12 * Unless required by applicable law or agreed to in writing, software
borlanic 0:02dd72d1d465 13 * distributed under the License is distributed on an "AS IS" BASIS,
borlanic 0:02dd72d1d465 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
borlanic 0:02dd72d1d465 15 * See the License for the specific language governing permissions and
borlanic 0:02dd72d1d465 16 * limitations under the License.
borlanic 0:02dd72d1d465 17 */
borlanic 0:02dd72d1d465 18 #ifndef MBED_CRITICAL_SECTION_API_H
borlanic 0:02dd72d1d465 19 #define MBED_CRITICAL_SECTION_API_H
borlanic 0:02dd72d1d465 20
borlanic 0:02dd72d1d465 21 #include <stdbool.h>
borlanic 0:02dd72d1d465 22
borlanic 0:02dd72d1d465 23 #ifdef __cplusplus
borlanic 0:02dd72d1d465 24 extern "C" {
borlanic 0:02dd72d1d465 25 #endif
borlanic 0:02dd72d1d465 26
borlanic 0:02dd72d1d465 27 /**
borlanic 0:02dd72d1d465 28 * \defgroup hal_critical Critical Section HAL functions
borlanic 0:02dd72d1d465 29 * @{
borlanic 0:02dd72d1d465 30 */
borlanic 0:02dd72d1d465 31
borlanic 0:02dd72d1d465 32 /**
borlanic 0:02dd72d1d465 33 * Mark the start of a critical section
borlanic 0:02dd72d1d465 34 *
borlanic 0:02dd72d1d465 35 * This function will be called by core_util_critical_section_enter() each time
borlanic 0:02dd72d1d465 36 * the application requests to enter a critical section. The purpose of the
borlanic 0:02dd72d1d465 37 * critical section is to ensure mutual-exclusion synchronisation of the
borlanic 0:02dd72d1d465 38 * processor by preventing any change in processor control, the default
borlanic 0:02dd72d1d465 39 * behaviour requires storing the state of interrupts in the system before
borlanic 0:02dd72d1d465 40 * disabling them.
borlanic 0:02dd72d1d465 41 *
borlanic 0:02dd72d1d465 42 * The critical section code supports nesting. When a thread has entered a
borlanic 0:02dd72d1d465 43 * critical section it can make additional calls to
borlanic 0:02dd72d1d465 44 * core_util_critical_section_enter() without deadlocking itself. The critical
borlanic 0:02dd72d1d465 45 * section driver API tracks the number of nested calls to the critical section.
borlanic 0:02dd72d1d465 46 * The critical section will only be exited when
borlanic 0:02dd72d1d465 47 * core_util_critical_section_exit() has been called once for each time it
borlanic 0:02dd72d1d465 48 * entered the critical section.
borlanic 0:02dd72d1d465 49 *
borlanic 0:02dd72d1d465 50 * On the first call to enter a critical section this function MUST store the
borlanic 0:02dd72d1d465 51 * state of any interrupts or other application settings it will modify to
borlanic 0:02dd72d1d465 52 * facilitate the critical section.
borlanic 0:02dd72d1d465 53 *
borlanic 0:02dd72d1d465 54 * Each successive call to enter the critical section MUST ignore storing or
borlanic 0:02dd72d1d465 55 * modifying any application state.
borlanic 0:02dd72d1d465 56 *
borlanic 0:02dd72d1d465 57 * The default implementation of this function which will save the current state
borlanic 0:02dd72d1d465 58 * of interrupts before disabling them. This implementation can be found in
borlanic 0:02dd72d1d465 59 * mbed_critical_section_api.c. This behaviour is can be overridden on a per
borlanic 0:02dd72d1d465 60 * platform basis by providing a different implementation within the correct
borlanic 0:02dd72d1d465 61 * targets directory.
borlanic 0:02dd72d1d465 62 */
borlanic 0:02dd72d1d465 63 void hal_critical_section_enter(void);
borlanic 0:02dd72d1d465 64
borlanic 0:02dd72d1d465 65
borlanic 0:02dd72d1d465 66 /** Mark the end of a critical section.
borlanic 0:02dd72d1d465 67 *
borlanic 0:02dd72d1d465 68 * The purpose of this function is to restore any state that was modified upon
borlanic 0:02dd72d1d465 69 * entering the critical section, allowing other threads or interrupts to change
borlanic 0:02dd72d1d465 70 * the processor control.
borlanic 0:02dd72d1d465 71 *
borlanic 0:02dd72d1d465 72 * This function will be called once by core_util_critical_section_exit() per
borlanic 0:02dd72d1d465 73 * critical section on last call to exit. When called, the application MUST
borlanic 0:02dd72d1d465 74 * restore the saved interrupt/application state that was saved when entering
borlanic 0:02dd72d1d465 75 * the critical section.
borlanic 0:02dd72d1d465 76 *
borlanic 0:02dd72d1d465 77 * There is a default implementation of this function, it will restore the state
borlanic 0:02dd72d1d465 78 * of interrupts that were previously saved when hal_critical_section_enter was
borlanic 0:02dd72d1d465 79 * first called, this implementation can be found in
borlanic 0:02dd72d1d465 80 * mbed_critical_section_api.c. This behaviour is overridable by providing a
borlanic 0:02dd72d1d465 81 * different function implementation within the correct targets directory.
borlanic 0:02dd72d1d465 82 */
borlanic 0:02dd72d1d465 83 void hal_critical_section_exit(void);
borlanic 0:02dd72d1d465 84
borlanic 0:02dd72d1d465 85
borlanic 0:02dd72d1d465 86 /** Determine if the application is currently running in a critical section
borlanic 0:02dd72d1d465 87 *
borlanic 0:02dd72d1d465 88 * The purpose of this function is to inform the caller whether or not the
borlanic 0:02dd72d1d465 89 * application is running in a critical section. This is done by checking if
borlanic 0:02dd72d1d465 90 * the current interrupt state has been saved in the underlying implementation,
borlanic 0:02dd72d1d465 91 * this could also be done by checking the state of the interrupts at the time
borlanic 0:02dd72d1d465 92 * of calling.
borlanic 0:02dd72d1d465 93 *
borlanic 0:02dd72d1d465 94 * @return True if running in a critical section, false if not.
borlanic 0:02dd72d1d465 95 */
borlanic 0:02dd72d1d465 96 bool hal_in_critical_section(void);
borlanic 0:02dd72d1d465 97
borlanic 0:02dd72d1d465 98
borlanic 0:02dd72d1d465 99 /**@}*/
borlanic 0:02dd72d1d465 100
borlanic 0:02dd72d1d465 101 #ifdef __cplusplus
borlanic 0:02dd72d1d465 102 }
borlanic 0:02dd72d1d465 103 #endif
borlanic 0:02dd72d1d465 104
borlanic 0:02dd72d1d465 105 #endif // MBED_CRITICAL_SECTION_API_H
borlanic 0:02dd72d1d465 106
borlanic 0:02dd72d1d465 107 /** @}*/