Marco Zecchini / Mbed OS Example_RTOS

Rtos API example

mbed-os/rtos/ConditionVariable.cpp@0:9fca2b23d0ba, 2019-02-23 (annotated)

Committer:
marcozecchini
Date:
Sat Feb 23 12:13:36 2019 +0000
Revision:
0:9fca2b23d0ba
final commit

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marcozecchini 0:9fca2b23d0ba 1 /* mbed Microcontroller Library
marcozecchini 0:9fca2b23d0ba 2 * Copyright (c) 2017-2017 ARM Limited
marcozecchini 0:9fca2b23d0ba 3 *
marcozecchini 0:9fca2b23d0ba 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
marcozecchini 0:9fca2b23d0ba 5 * of this software and associated documentation files (the "Software"), to deal
marcozecchini 0:9fca2b23d0ba 6 * in the Software without restriction, including without limitation the rights
marcozecchini 0:9fca2b23d0ba 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
marcozecchini 0:9fca2b23d0ba 8 * copies of the Software, and to permit persons to whom the Software is
marcozecchini 0:9fca2b23d0ba 9 * furnished to do so, subject to the following conditions:
marcozecchini 0:9fca2b23d0ba 10 *
marcozecchini 0:9fca2b23d0ba 11 * The above copyright notice and this permission notice shall be included in
marcozecchini 0:9fca2b23d0ba 12 * all copies or substantial portions of the Software.
marcozecchini 0:9fca2b23d0ba 13 *
marcozecchini 0:9fca2b23d0ba 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
marcozecchini 0:9fca2b23d0ba 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
marcozecchini 0:9fca2b23d0ba 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
marcozecchini 0:9fca2b23d0ba 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
marcozecchini 0:9fca2b23d0ba 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
marcozecchini 0:9fca2b23d0ba 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
marcozecchini 0:9fca2b23d0ba 20 * SOFTWARE.
marcozecchini 0:9fca2b23d0ba 21 */
marcozecchini 0:9fca2b23d0ba 22 #include "rtos/ConditionVariable.h"
marcozecchini 0:9fca2b23d0ba 23 #include "rtos/Thread.h"
marcozecchini 0:9fca2b23d0ba 24
marcozecchini 0:9fca2b23d0ba 25 #include "mbed_error.h"
marcozecchini 0:9fca2b23d0ba 26 #include "mbed_assert.h"
marcozecchini 0:9fca2b23d0ba 27
marcozecchini 0:9fca2b23d0ba 28 namespace rtos {
marcozecchini 0:9fca2b23d0ba 29
marcozecchini 0:9fca2b23d0ba 30
marcozecchini 0:9fca2b23d0ba 31 ConditionVariable::Waiter::Waiter(): sem(0), prev(NULL), next(NULL), in_list(false)
marcozecchini 0:9fca2b23d0ba 32 {
marcozecchini 0:9fca2b23d0ba 33 // No initialization to do
marcozecchini 0:9fca2b23d0ba 34 }
marcozecchini 0:9fca2b23d0ba 35
marcozecchini 0:9fca2b23d0ba 36 ConditionVariable::ConditionVariable(Mutex &mutex): _mutex(mutex), _wait_list(NULL)
marcozecchini 0:9fca2b23d0ba 37 {
marcozecchini 0:9fca2b23d0ba 38 // No initialization to do
marcozecchini 0:9fca2b23d0ba 39 }
marcozecchini 0:9fca2b23d0ba 40
marcozecchini 0:9fca2b23d0ba 41 void ConditionVariable::wait()
marcozecchini 0:9fca2b23d0ba 42 {
marcozecchini 0:9fca2b23d0ba 43 wait_for(osWaitForever);
marcozecchini 0:9fca2b23d0ba 44 }
marcozecchini 0:9fca2b23d0ba 45
marcozecchini 0:9fca2b23d0ba 46 bool ConditionVariable::wait_for(uint32_t millisec)
marcozecchini 0:9fca2b23d0ba 47 {
marcozecchini 0:9fca2b23d0ba 48 Waiter current_thread;
marcozecchini 0:9fca2b23d0ba 49 MBED_ASSERT(_mutex.get_owner() == Thread::gettid());
marcozecchini 0:9fca2b23d0ba 50 MBED_ASSERT(_mutex._count == 1);
marcozecchini 0:9fca2b23d0ba 51 _add_wait_list(&_wait_list, &current_thread);
marcozecchini 0:9fca2b23d0ba 52
marcozecchini 0:9fca2b23d0ba 53 _mutex.unlock();
marcozecchini 0:9fca2b23d0ba 54
marcozecchini 0:9fca2b23d0ba 55 int32_t sem_count = current_thread.sem.wait(millisec);
marcozecchini 0:9fca2b23d0ba 56 bool timeout = (sem_count > 0) ? false : true;
marcozecchini 0:9fca2b23d0ba 57
marcozecchini 0:9fca2b23d0ba 58 _mutex.lock();
marcozecchini 0:9fca2b23d0ba 59
marcozecchini 0:9fca2b23d0ba 60 if (current_thread.in_list) {
marcozecchini 0:9fca2b23d0ba 61 _remove_wait_list(&_wait_list, &current_thread);
marcozecchini 0:9fca2b23d0ba 62 }
marcozecchini 0:9fca2b23d0ba 63
marcozecchini 0:9fca2b23d0ba 64 return timeout;
marcozecchini 0:9fca2b23d0ba 65 }
marcozecchini 0:9fca2b23d0ba 66
marcozecchini 0:9fca2b23d0ba 67 void ConditionVariable::notify_one()
marcozecchini 0:9fca2b23d0ba 68 {
marcozecchini 0:9fca2b23d0ba 69 MBED_ASSERT(_mutex.get_owner() == Thread::gettid());
marcozecchini 0:9fca2b23d0ba 70 if (_wait_list != NULL) {
marcozecchini 0:9fca2b23d0ba 71 _wait_list->sem.release();
marcozecchini 0:9fca2b23d0ba 72 _remove_wait_list(&_wait_list, _wait_list);
marcozecchini 0:9fca2b23d0ba 73 }
marcozecchini 0:9fca2b23d0ba 74 }
marcozecchini 0:9fca2b23d0ba 75
marcozecchini 0:9fca2b23d0ba 76 void ConditionVariable::notify_all()
marcozecchini 0:9fca2b23d0ba 77 {
marcozecchini 0:9fca2b23d0ba 78 MBED_ASSERT(_mutex.get_owner() == Thread::gettid());
marcozecchini 0:9fca2b23d0ba 79 while (_wait_list != NULL) {
marcozecchini 0:9fca2b23d0ba 80 _wait_list->sem.release();
marcozecchini 0:9fca2b23d0ba 81 _remove_wait_list(&_wait_list, _wait_list);
marcozecchini 0:9fca2b23d0ba 82 }
marcozecchini 0:9fca2b23d0ba 83 }
marcozecchini 0:9fca2b23d0ba 84
marcozecchini 0:9fca2b23d0ba 85 void ConditionVariable::_add_wait_list(Waiter **wait_list, Waiter *waiter)
marcozecchini 0:9fca2b23d0ba 86 {
marcozecchini 0:9fca2b23d0ba 87 if (NULL == *wait_list) {
marcozecchini 0:9fca2b23d0ba 88 // Nothing in the list so add it directly.
marcozecchini 0:9fca2b23d0ba 89 // Update prev and next pointer to reference self
marcozecchini 0:9fca2b23d0ba 90 *wait_list = waiter;
marcozecchini 0:9fca2b23d0ba 91 waiter->next = waiter;
marcozecchini 0:9fca2b23d0ba 92 waiter->prev = waiter;
marcozecchini 0:9fca2b23d0ba 93 } else {
marcozecchini 0:9fca2b23d0ba 94 // Add after the last element
marcozecchini 0:9fca2b23d0ba 95 Waiter *first = *wait_list;
marcozecchini 0:9fca2b23d0ba 96 Waiter *last = (*wait_list)->prev;
marcozecchini 0:9fca2b23d0ba 97
marcozecchini 0:9fca2b23d0ba 98 // Update new entry
marcozecchini 0:9fca2b23d0ba 99 waiter->next = first;
marcozecchini 0:9fca2b23d0ba 100 waiter->prev = last;
marcozecchini 0:9fca2b23d0ba 101
marcozecchini 0:9fca2b23d0ba 102 // Insert into the list
marcozecchini 0:9fca2b23d0ba 103 first->prev = waiter;
marcozecchini 0:9fca2b23d0ba 104 last->next = waiter;
marcozecchini 0:9fca2b23d0ba 105 }
marcozecchini 0:9fca2b23d0ba 106 waiter->in_list = true;
marcozecchini 0:9fca2b23d0ba 107 }
marcozecchini 0:9fca2b23d0ba 108
marcozecchini 0:9fca2b23d0ba 109 void ConditionVariable::_remove_wait_list(Waiter **wait_list, Waiter *waiter)
marcozecchini 0:9fca2b23d0ba 110 {
marcozecchini 0:9fca2b23d0ba 111 Waiter *prev = waiter->prev;
marcozecchini 0:9fca2b23d0ba 112 Waiter *next = waiter->next;
marcozecchini 0:9fca2b23d0ba 113
marcozecchini 0:9fca2b23d0ba 114 // Remove from list
marcozecchini 0:9fca2b23d0ba 115 prev->next = waiter->next;
marcozecchini 0:9fca2b23d0ba 116 next->prev = waiter->prev;
marcozecchini 0:9fca2b23d0ba 117 *wait_list = waiter->next;
marcozecchini 0:9fca2b23d0ba 118
marcozecchini 0:9fca2b23d0ba 119 if (*wait_list == waiter) {
marcozecchini 0:9fca2b23d0ba 120 // This was the last element in the list
marcozecchini 0:9fca2b23d0ba 121 *wait_list = NULL;
marcozecchini 0:9fca2b23d0ba 122 }
marcozecchini 0:9fca2b23d0ba 123
marcozecchini 0:9fca2b23d0ba 124 // Invalidate pointers
marcozecchini 0:9fca2b23d0ba 125 waiter->next = NULL;
marcozecchini 0:9fca2b23d0ba 126 waiter->prev = NULL;
marcozecchini 0:9fca2b23d0ba 127 waiter->in_list = false;
marcozecchini 0:9fca2b23d0ba 128 }
marcozecchini 0:9fca2b23d0ba 129
marcozecchini 0:9fca2b23d0ba 130 ConditionVariable::~ConditionVariable()
marcozecchini 0:9fca2b23d0ba 131 {
marcozecchini 0:9fca2b23d0ba 132 MBED_ASSERT(NULL == _wait_list);
marcozecchini 0:9fca2b23d0ba 133 }
marcozecchini 0:9fca2b23d0ba 134
marcozecchini 0:9fca2b23d0ba 135 }