Daniel Vizcaya / Mbed OS 04_RTOS_Embebidos

Entrega 3er corte - sistemas embebidos

mbed-os/rtos/ConditionVariable.cpp@1:fcdb45ee95b9, 2018-05-30 (annotated)

Committer:
Bethory
Date:
Wed May 30 04:46:28 2018 +0000
Revision:
1:fcdb45ee95b9
Parent:
0:6ad07c9019fd 
Entrega Final

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Bethory 0:6ad07c9019fd 1 /* mbed Microcontroller Library
Bethory 0:6ad07c9019fd 2 * Copyright (c) 2017-2017 ARM Limited
Bethory 0:6ad07c9019fd 3 *
Bethory 0:6ad07c9019fd 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
Bethory 0:6ad07c9019fd 5 * of this software and associated documentation files (the "Software"), to deal
Bethory 0:6ad07c9019fd 6 * in the Software without restriction, including without limitation the rights
Bethory 0:6ad07c9019fd 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
Bethory 0:6ad07c9019fd 8 * copies of the Software, and to permit persons to whom the Software is
Bethory 0:6ad07c9019fd 9 * furnished to do so, subject to the following conditions:
Bethory 0:6ad07c9019fd 10 *
Bethory 0:6ad07c9019fd 11 * The above copyright notice and this permission notice shall be included in
Bethory 0:6ad07c9019fd 12 * all copies or substantial portions of the Software.
Bethory 0:6ad07c9019fd 13 *
Bethory 0:6ad07c9019fd 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
Bethory 0:6ad07c9019fd 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
Bethory 0:6ad07c9019fd 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
Bethory 0:6ad07c9019fd 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
Bethory 0:6ad07c9019fd 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
Bethory 0:6ad07c9019fd 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
Bethory 0:6ad07c9019fd 20 * SOFTWARE.
Bethory 0:6ad07c9019fd 21 */
Bethory 0:6ad07c9019fd 22 #include "rtos/ConditionVariable.h"
Bethory 0:6ad07c9019fd 23 #include "rtos/Kernel.h"
Bethory 0:6ad07c9019fd 24 #include "rtos/Thread.h"
Bethory 0:6ad07c9019fd 25
Bethory 0:6ad07c9019fd 26 #include "mbed_error.h"
Bethory 0:6ad07c9019fd 27 #include "mbed_assert.h"
Bethory 0:6ad07c9019fd 28
Bethory 0:6ad07c9019fd 29 namespace rtos {
Bethory 0:6ad07c9019fd 30
Bethory 0:6ad07c9019fd 31 ConditionVariable::Waiter::Waiter(): sem(0), prev(NULL), next(NULL), in_list(false)
Bethory 0:6ad07c9019fd 32 {
Bethory 0:6ad07c9019fd 33 // No initialization to do
Bethory 0:6ad07c9019fd 34 }
Bethory 0:6ad07c9019fd 35
Bethory 0:6ad07c9019fd 36 ConditionVariable::ConditionVariable(Mutex &mutex): _mutex(mutex), _wait_list(NULL)
Bethory 0:6ad07c9019fd 37 {
Bethory 0:6ad07c9019fd 38 // No initialization to do
Bethory 0:6ad07c9019fd 39 }
Bethory 0:6ad07c9019fd 40
Bethory 0:6ad07c9019fd 41 void ConditionVariable::wait()
Bethory 0:6ad07c9019fd 42 {
Bethory 0:6ad07c9019fd 43 wait_for(osWaitForever);
Bethory 0:6ad07c9019fd 44 }
Bethory 0:6ad07c9019fd 45
Bethory 0:6ad07c9019fd 46 bool ConditionVariable::wait_for(uint32_t millisec)
Bethory 0:6ad07c9019fd 47 {
Bethory 0:6ad07c9019fd 48 Waiter current_thread;
Bethory 0:6ad07c9019fd 49 MBED_ASSERT(_mutex.get_owner() == Thread::gettid());
Bethory 0:6ad07c9019fd 50 MBED_ASSERT(_mutex._count == 1);
Bethory 0:6ad07c9019fd 51 _add_wait_list(&_wait_list, &current_thread);
Bethory 0:6ad07c9019fd 52
Bethory 0:6ad07c9019fd 53 _mutex.unlock();
Bethory 0:6ad07c9019fd 54
Bethory 0:6ad07c9019fd 55 int32_t sem_count = current_thread.sem.wait(millisec);
Bethory 0:6ad07c9019fd 56 bool timeout = (sem_count > 0) ? false : true;
Bethory 0:6ad07c9019fd 57
Bethory 0:6ad07c9019fd 58 _mutex.lock();
Bethory 0:6ad07c9019fd 59
Bethory 0:6ad07c9019fd 60 if (current_thread.in_list) {
Bethory 0:6ad07c9019fd 61 _remove_wait_list(&_wait_list, &current_thread);
Bethory 0:6ad07c9019fd 62 }
Bethory 0:6ad07c9019fd 63
Bethory 0:6ad07c9019fd 64 return timeout;
Bethory 0:6ad07c9019fd 65 }
Bethory 0:6ad07c9019fd 66
Bethory 0:6ad07c9019fd 67 bool ConditionVariable::wait_until(uint64_t millisec)
Bethory 0:6ad07c9019fd 68 {
Bethory 0:6ad07c9019fd 69 uint64_t now = Kernel::get_ms_count();
Bethory 0:6ad07c9019fd 70
Bethory 0:6ad07c9019fd 71 if (now >= millisec) {
Bethory 0:6ad07c9019fd 72 // Time has already passed - standard behaviour is to
Bethory 0:6ad07c9019fd 73 // treat as a "try".
Bethory 0:6ad07c9019fd 74 return wait_for(0);
Bethory 0:6ad07c9019fd 75 } else if (millisec - now >= osWaitForever) {
Bethory 0:6ad07c9019fd 76 // Exceeds maximum delay of underlying wait_for -
Bethory 0:6ad07c9019fd 77 // spuriously wake after 49 days, indicating no timeout.
Bethory 0:6ad07c9019fd 78 wait_for(osWaitForever - 1);
Bethory 0:6ad07c9019fd 79 return false;
Bethory 0:6ad07c9019fd 80 } else {
Bethory 0:6ad07c9019fd 81 return wait_for(millisec - now);
Bethory 0:6ad07c9019fd 82 }
Bethory 0:6ad07c9019fd 83 }
Bethory 0:6ad07c9019fd 84
Bethory 0:6ad07c9019fd 85 void ConditionVariable::notify_one()
Bethory 0:6ad07c9019fd 86 {
Bethory 0:6ad07c9019fd 87 MBED_ASSERT(_mutex.get_owner() == Thread::gettid());
Bethory 0:6ad07c9019fd 88 if (_wait_list != NULL) {
Bethory 0:6ad07c9019fd 89 _wait_list->sem.release();
Bethory 0:6ad07c9019fd 90 _remove_wait_list(&_wait_list, _wait_list);
Bethory 0:6ad07c9019fd 91 }
Bethory 0:6ad07c9019fd 92 }
Bethory 0:6ad07c9019fd 93
Bethory 0:6ad07c9019fd 94 void ConditionVariable::notify_all()
Bethory 0:6ad07c9019fd 95 {
Bethory 0:6ad07c9019fd 96 MBED_ASSERT(_mutex.get_owner() == Thread::gettid());
Bethory 0:6ad07c9019fd 97 while (_wait_list != NULL) {
Bethory 0:6ad07c9019fd 98 _wait_list->sem.release();
Bethory 0:6ad07c9019fd 99 _remove_wait_list(&_wait_list, _wait_list);
Bethory 0:6ad07c9019fd 100 }
Bethory 0:6ad07c9019fd 101 }
Bethory 0:6ad07c9019fd 102
Bethory 0:6ad07c9019fd 103 void ConditionVariable::_add_wait_list(Waiter **wait_list, Waiter *waiter)
Bethory 0:6ad07c9019fd 104 {
Bethory 0:6ad07c9019fd 105 if (NULL == *wait_list) {
Bethory 0:6ad07c9019fd 106 // Nothing in the list so add it directly.
Bethory 0:6ad07c9019fd 107 // Update prev and next pointer to reference self
Bethory 0:6ad07c9019fd 108 *wait_list = waiter;
Bethory 0:6ad07c9019fd 109 waiter->next = waiter;
Bethory 0:6ad07c9019fd 110 waiter->prev = waiter;
Bethory 0:6ad07c9019fd 111 } else {
Bethory 0:6ad07c9019fd 112 // Add after the last element
Bethory 0:6ad07c9019fd 113 Waiter *first = *wait_list;
Bethory 0:6ad07c9019fd 114 Waiter *last = (*wait_list)->prev;
Bethory 0:6ad07c9019fd 115
Bethory 0:6ad07c9019fd 116 // Update new entry
Bethory 0:6ad07c9019fd 117 waiter->next = first;
Bethory 0:6ad07c9019fd 118 waiter->prev = last;
Bethory 0:6ad07c9019fd 119
Bethory 0:6ad07c9019fd 120 // Insert into the list
Bethory 0:6ad07c9019fd 121 first->prev = waiter;
Bethory 0:6ad07c9019fd 122 last->next = waiter;
Bethory 0:6ad07c9019fd 123 }
Bethory 0:6ad07c9019fd 124 waiter->in_list = true;
Bethory 0:6ad07c9019fd 125 }
Bethory 0:6ad07c9019fd 126
Bethory 0:6ad07c9019fd 127 void ConditionVariable::_remove_wait_list(Waiter **wait_list, Waiter *waiter)
Bethory 0:6ad07c9019fd 128 {
Bethory 0:6ad07c9019fd 129 Waiter *prev = waiter->prev;
Bethory 0:6ad07c9019fd 130 Waiter *next = waiter->next;
Bethory 0:6ad07c9019fd 131
Bethory 0:6ad07c9019fd 132 // Remove from list
Bethory 0:6ad07c9019fd 133 prev->next = waiter->next;
Bethory 0:6ad07c9019fd 134 next->prev = waiter->prev;
Bethory 0:6ad07c9019fd 135 *wait_list = waiter->next;
Bethory 0:6ad07c9019fd 136
Bethory 0:6ad07c9019fd 137 if (*wait_list == waiter) {
Bethory 0:6ad07c9019fd 138 // This was the last element in the list
Bethory 0:6ad07c9019fd 139 *wait_list = NULL;
Bethory 0:6ad07c9019fd 140 }
Bethory 0:6ad07c9019fd 141
Bethory 0:6ad07c9019fd 142 // Invalidate pointers
Bethory 0:6ad07c9019fd 143 waiter->next = NULL;
Bethory 0:6ad07c9019fd 144 waiter->prev = NULL;
Bethory 0:6ad07c9019fd 145 waiter->in_list = false;
Bethory 0:6ad07c9019fd 146 }
Bethory 0:6ad07c9019fd 147
Bethory 0:6ad07c9019fd 148 ConditionVariable::~ConditionVariable()
Bethory 0:6ad07c9019fd 149 {
Bethory 0:6ad07c9019fd 150 MBED_ASSERT(NULL == _wait_list);
Bethory 0:6ad07c9019fd 151 }
Bethory 0:6ad07c9019fd 152
Bethory 0:6ad07c9019fd 153 }