Merge pull request #3648 from c1728p9/condition_variable

Add ConditionVariable to mbed rtos

Author: 0xc0170

TESTS/mbedmicro-rtos-mbed/condition_variable/main.cpp

@@ -0,0 +1,111 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "mbed.h"
+#include "greentea-client/test_env.h"
+#include "unity.h"
+#include "utest.h"
+#include "rtos.h"
+
+#if defined(MBED_RTOS_SINGLE_THREAD)
+  #error [NOT_SUPPORTED] test not supported
+#endif
+
+using namespace utest::v1;
+
+#define TEST_STACK_SIZE 512
+#define TEST_DELAY 10
+
+static int change_counter = 0;
+static Mutex mutex;
+static ConditionVariable cond(mutex);
+
+void increment_on_signal()
+{
+    mutex.lock();
+
+    cond.wait();
+    change_counter++;
+
+    mutex.unlock();
+}
+
+void test_notify_one()
+{
+    Thread t1(osPriorityNormal, TEST_STACK_SIZE);
+    Thread t2(osPriorityNormal, TEST_STACK_SIZE);
+
+    change_counter = 0;
+    t1.start(increment_on_signal);
+    t2.start(increment_on_signal);
+
+    wait_ms(TEST_DELAY);
+    TEST_ASSERT_EQUAL(0, change_counter);
+
+    mutex.lock();
+    cond.notify_one();
+    mutex.unlock();
+
+    wait_ms(TEST_DELAY);
+    TEST_ASSERT_EQUAL(1, change_counter);
+
+    mutex.lock();
+    cond.notify_one();
+    mutex.unlock();
+
+    t1.join();
+    t2.join();
+}
+
+void test_notify_all()
+{
+    Thread t1(osPriorityNormal, TEST_STACK_SIZE);
+    Thread t2(osPriorityNormal, TEST_STACK_SIZE);
+
+    change_counter = 0;
+    t1.start(increment_on_signal);
+    t2.start(increment_on_signal);
+
+    wait_ms(TEST_DELAY);
+    TEST_ASSERT_EQUAL(0, change_counter);
+
+    mutex.lock();
+    cond.notify_all();
+    mutex.unlock();
+
+    wait_ms(TEST_DELAY);
+    TEST_ASSERT_EQUAL(2, change_counter);
+
+    t1.join();
+    t2.join();
+}
+
+utest::v1::status_t test_setup(const size_t number_of_cases)
+{
+    GREENTEA_SETUP(10, "default_auto");
+    return verbose_test_setup_handler(number_of_cases);
+}
+
+Case cases[] = {
+    Case("Test notify one", test_notify_one),
+    Case("Test notify all", test_notify_all),
+};
+
+Specification specification(test_setup, cases);
+
+int main()
+{
+    return !Harness::run(specification);
+}

rtos/ConditionVariable.cpp

@@ -0,0 +1,136 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017-2017 ARM Limited
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include "rtos/ConditionVariable.h"
+#include "rtos/Semaphore.h"
+#include "rtos/Thread.h"
+
+#include "mbed_error.h"
+#include "mbed_assert.h"
+
+namespace rtos {
+
+#define RESUME_SIGNAL      (1 << 15)
+
+struct Waiter {
+    Waiter();
+    Semaphore sem;
+    Waiter *prev;
+    Waiter *next;
+    bool in_list;
+};
+
+Waiter::Waiter(): sem(0), prev(NULL), next(NULL), in_list(false)
+{
+    // No initialization to do
+}
+
+ConditionVariable::ConditionVariable(Mutex &mutex): _mutex(mutex), _wait_list(NULL)
+{
+    // No initialization to do
+}
+
+void ConditionVariable::wait()
+{
+    wait_for(osWaitForever);
+}
+
+bool ConditionVariable::wait_for(uint32_t millisec)
+{
+    Waiter current_thread;
+    MBED_ASSERT(_mutex.get_owner() == Thread::gettid());
+    MBED_ASSERT(_mutex._count == 1);
+    _add_wait_list(&current_thread);
+
+    _mutex.unlock();
+
+    int32_t sem_count = current_thread.sem.wait(millisec);
+    bool timeout = (sem_count > 0) ? false : true;
+
+    _mutex.lock();
+
+    if (current_thread.in_list) {
+        _remove_wait_list(&current_thread);
+    }
+
+    return timeout;
+}
+
+void ConditionVariable::notify_one()
+{
+    MBED_ASSERT(_mutex.get_owner() == Thread::gettid());
+    if (_wait_list != NULL) {
+        _wait_list->sem.release();
+        _remove_wait_list(_wait_list);
+    }
+}
+
+void ConditionVariable::notify_all()
+{
+    MBED_ASSERT(_mutex.get_owner() == Thread::gettid());
+    while (_wait_list != NULL) {
+        _wait_list->sem.release();
+        _remove_wait_list(_wait_list);
+    }
+}
+
+void ConditionVariable::_add_wait_list(Waiter * waiter)
+{
+    if (NULL == _wait_list) {
+        // Nothing in the list so add it directly.
+        // Update prev pointer to reference self
+        _wait_list = waiter;
+        waiter->prev = waiter;
+    } else {
+        // Add after the last element
+        Waiter *last = _wait_list->prev;
+        last->next = waiter;
+        waiter->prev = last;
+        _wait_list->prev = waiter;
+    }
+    waiter->in_list = true;
+}
+
+void ConditionVariable::_remove_wait_list(Waiter * waiter)
+{
+    // Remove this element from the start of the list
+    Waiter * next = waiter->next;
+    if (waiter == _wait_list) {
+        _wait_list = next;
+    }
+    if (next != NULL) {
+        next = waiter->prev;
+    }
+    Waiter * prev = waiter->prev;
+    if (prev != NULL) {
+        prev = waiter->next;
+    }
+    waiter->next = NULL;
+    waiter->prev = NULL;
+    waiter->in_list = false;
+}
+
+ConditionVariable::~ConditionVariable()
+{
+    MBED_ASSERT(NULL == _wait_list);
+}
+
+}