mirror of https://github.com/ARMmbed/mbed-os.git
153 lines
3.2 KiB
C++
153 lines
3.2 KiB
C++
/*
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* Copyright (c) 2018-2019, Arm Limited and affiliates.
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "drivers/internal/TaskBase.h"
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#include "drivers/internal/TaskQueue.h"
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#include "events/mbed_events.h"
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#include "rtos/Semaphore.h"
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#include "platform/mbed_critical.h"
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TaskBase::TaskBase(TaskQueue *q)
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: _queue(q), _posted(false), _start_count(0), _flush_sem(NULL)
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{
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}
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TaskBase::~TaskBase()
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{
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cancel();
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wait();
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}
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void TaskBase::set(TaskQueue *q)
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{
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core_util_critical_section_enter();
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// Cannot set the queue when it has been posted but has not been finished
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MBED_ASSERT(!_posted);
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_queue = q;
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core_util_critical_section_exit();
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}
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void TaskBase::cancel()
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{
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core_util_critical_section_enter();
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if (_posted) {
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_queue->cancel(this);
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_posted = false;
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_wake_check();
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}
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core_util_critical_section_exit();
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}
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void TaskBase::wait()
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{
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// Fast path check for finished
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core_util_critical_section_enter();
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if (finished()) {
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core_util_critical_section_exit();
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return;
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}
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core_util_critical_section_exit();
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rtos::Semaphore sem;
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// If the event is in-flight then wait for it to complete
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core_util_critical_section_enter();
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if (finished()) {
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// This element has been flushed from the queue
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core_util_critical_section_exit();
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return;
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}
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_flush_sem = &sem;
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core_util_critical_section_exit();
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sem.acquire();
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}
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bool TaskBase::ready()
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{
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core_util_critical_section_enter();
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bool is_ready = !_posted;
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core_util_critical_section_exit();
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return is_ready;
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}
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bool TaskBase::finished()
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{
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core_util_critical_section_enter();
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bool is_finished = !_posted && (_start_count == 0);
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core_util_critical_section_exit();
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return is_finished;
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}
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void TaskBase::finish()
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{
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// Nothing to do
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}
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void TaskBase::post()
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{
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core_util_critical_section_enter();
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MBED_ASSERT(_queue);
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if (_queue) {
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MBED_ASSERT(!_posted);
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_queue->post(this);
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_posted = true;
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}
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core_util_critical_section_exit();
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}
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TaskBase::run_callback_t TaskBase::_start(void *buffer, uint32_t size)
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{
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// Each call to _start must result in a call to _finish
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MBED_ASSERT(_start_count < 0xFFFF);
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_start_count++;
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_posted = false;
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return start(buffer, size);
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}
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void TaskBase::_finish()
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{
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// Each call to _finish must be preceded by a call to _start
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MBED_ASSERT(_start_count > 0);
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_start_count--;
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_wake_check();
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finish();
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}
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void TaskBase::_wake_check()
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{
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if (!finished()) {
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return;
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}
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if (_flush_sem) {
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_flush_sem->release();
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_flush_sem = NULL;
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}
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}
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