qpcpp/qk/source/qk_mutex.cpp

//****************************************************************************
// Product: QK/C++
// Last Updated for Version: 5.1.0
// Date of the Last Update:  Sep 28, 2013
//
//                    Q u a n t u m     L e a P s
//                    ---------------------------
//                    innovating embedded systems
//
// Copyright (C) 2002-2013 Quantum Leaps, LLC. All rights reserved.
//
// This program is open source software: you can redistribute it and/or
// modify it under the terms of the GNU General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Alternatively, this program may be distributed and modified under the
// terms of Quantum Leaps commercial licenses, which expressly supersede
// the GNU General Public License and are specifically designed for
// licensees interested in retaining the proprietary status of their code.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
// Contact information:
// Quantum Leaps Web sites: http://www.quantum-leaps.com
//                          http://www.state-machine.com
// e-mail:                  info@quantum-leaps.com
//****************************************************************************
#include "qk_pkg.h"
//#include "qassert.h"

/// \file
/// \ingroup qk
/// \brief QK::mutexLock()/QK::mutexUnlock() implementation.

#ifdef QK_NO_MUTEX
    #error "qk_mutex.cpp included in the build when QK_NO_MUTEX defined"
#endif

// package-scope objects -----------------------------------------------------
extern "C" {
    uint8_t volatile QK_ceilingPrio_;           // ceiling priority of a mutex
}

namespace QP {

//Q_DEFINE_THIS_MODULE("qk_mutex")

//............................................................................
QMutex QK::mutexLock(uint8_t const prioCeiling) {
    QF_CRIT_STAT_
    QF_CRIT_ENTRY_();
    uint8_t mutex = QK_ceilingPrio_; // original QK priority ceiling to return
    if (QK_ceilingPrio_ < prioCeiling) {
        QK_ceilingPrio_ = prioCeiling;        // raise the QK priority ceiling
    }

    QS_BEGIN_NOCRIT_(QS_QK_MUTEX_LOCK,
                     static_cast<void *>(0), static_cast<void *>(0))
        QS_TIME_();                                               // timestamp
        QS_U8_(mutex);                                // the original priority
        QS_U8_(QK_ceilingPrio_);               // the current priority ceiling
    QS_END_NOCRIT_()

    QF_CRIT_EXIT_();
    return mutex;
}
//............................................................................
void QK::mutexUnlock(QMutex mutex) {
    QF_CRIT_STAT_
    QF_CRIT_ENTRY_();

    QS_BEGIN_NOCRIT_(QS_QK_MUTEX_UNLOCK,
                     static_cast<void *>(0), static_cast<void *>(0))
        QS_TIME_();                                               // timestamp
        QS_U8_(mutex);                                // the original priority
        QS_U8_(QK_ceilingPrio_);               // the current priority ceiling
    QS_END_NOCRIT_()

    if (QK_ceilingPrio_ > mutex) {
        QK_ceilingPrio_ = mutex;         // restore the saved priority ceiling
        mutex = QK_schedPrio_();             // reuse 'mutex' to hold priority
        if (mutex != static_cast<uint8_t>(0)) {
            QK_sched_(mutex);
        }
    }
    QF_CRIT_EXIT_();
}

}                                                              // namespace QP