qpc/ports/posix/qf_port.h

/*****************************************************************************
* Product:  QF/C, port to 80x86, POSIX/P-threads
* Last Updated for Version: 5.0.0
* Date of the Last Update:  Sep 13, 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
*****************************************************************************/
#ifndef qf_port_h
#define qf_port_h

                                      /* Linux event queue and thread types */
#define QF_EQUEUE_TYPE              QEQueue
#define QF_OS_OBJECT_TYPE           pthread_cond_t
#define QF_THREAD_TYPE              uint8_t

                 /* The maximum number of active objects in the application */
#define QF_MAX_ACTIVE               63
                                   /* The number of system clock tick rates */
#define QF_MAX_TICK_RATE            2

                     /* various QF object sizes configuration for this port */
#define QF_EVENT_SIZ_SIZE           4
#define QF_EQUEUE_CTR_SIZE          4
#define QF_MPOOL_SIZ_SIZE           4
#define QF_MPOOL_CTR_SIZE           4
#define QF_TIMEEVT_CTR_SIZE         4

                    /* QF critical section entry/exit for Linux, see NOTE01 */
/* QF_CRIT_STAT_TYPE not defined */
#define QF_CRIT_ENTRY(dummy)        pthread_mutex_lock(&QF_pThreadMutex_)
#define QF_CRIT_EXIT(dummy)         pthread_mutex_unlock(&QF_pThreadMutex_)

#include <pthread.h>                                    /* POSIX-thread API */
#include "qep_port.h"                                           /* QEP port */
#include "qequeue.h"                             /* Linux needs event-queue */
#include "qmpool.h"                              /* Linux needs memory-pool */
#include "qf.h"                 /* QF platform-independent public interface */

void QF_setTickRate(uint32_t ticksPerSec);           /* set clock tick rate */
void QF_onClockTick(void);     /* clock tick callback (provided in the app) */

extern pthread_mutex_t QF_pThreadMutex_;   /* mutex for QF critical section */

/*****************************************************************************
* interface used only inside QF, but not in applications
*/
#ifdef qf_pkg_h
                                      /* OS-object implementation for Linux */
    #define QACTIVE_EQUEUE_WAIT_(me_) \
        while ((me_)->eQueue.frontEvt == (QEvt *)0) \
            pthread_cond_wait(&(me_)->osObject, &QF_pThreadMutex_)

    #define QACTIVE_EQUEUE_SIGNAL_(me_) \
        pthread_cond_signal(&(me_)->osObject)

    #define QACTIVE_EQUEUE_ONEMPTY_(me_) ((void)0)

                                         /* native QF event pool operations */
    #define QF_EPOOL_TYPE_            QMPool
    #define QF_EPOOL_INIT_(p_, poolSto_, poolSize_, evtSize_) \
        QMPool_init(&(p_), poolSto_, poolSize_, evtSize_)
    #define QF_EPOOL_EVENT_SIZE_(p_)  ((p_).blockSize)
    #define QF_EPOOL_GET_(p_, e_, m_) ((e_) = (QEvt *)QMPool_get(&(p_), (m_)))
    #define QF_EPOOL_PUT_(p_, e_)     (QMPool_put(&(p_), e_))

#endif

/*****************************************************************************
*
* NOTE01:
* QF, like all real-time frameworks, needs to execute certain sections of
* code indivisibly to avoid data corruption. The most straightforward way of
* protecting such critical sections of code is disabling and enabling
* interrupts, which Linux does not allow.
*
* This QF port uses therefore a single package-scope p-thread mutex
* QF_pThreadMutex_ to protect all critical sections. The mutex is locked upon
* the entry to each critical sectioni and unlocked upon exit.
*
* Using the single mutex for all crtical section guarantees that only one
* thread at a time can execute inside a critical section. This prevents race
* conditions and data corruption.
*
* Please note, however, that the mutex implementation of a critical section
* behaves differently than the standard interrupt locking. A common mutex
* ensures that only one thread at a time can execute a critical section, but
* it does not guarantee that a context switch cannot occur within the
* critical section. In fact, such context switches probably will happen, but
* they should not cause concurrency hazards because the mutex eliminates all
* race conditionis.
*
* Unlinke simply disabling and enabling interrupts, the mutex approach is
* also subject to priority inversions. However, the p-thread mutex
* implementation, such as Linux p-threads, should support the priority-
* inheritance protocol.
*/

#endif                                                         /* qf_port_h */