qf_port.h

state machine working with rtos

/*****************************************************************************
* Product:  QF/C, port to 80x86, Linux/P-threads, gcc
* Last Updated for Version: 3.2.01
* Date of the Last Update:  Oct 19, 2006
*
* Copyright (C) 2002-2006 Quantum Leaps, LLC. All rights reserved.
*
* This QF/C port is part of the Quantum Leaps QF/C software, and may be
* distributed and modified under the terms of the GNU General Public License
* version 2 (GPL) as published by the Free Software Foundation and appearing
* in the file GPL.TXT included in the packaging of this file. Please note
* that GPL Section 2[b] requires that all works based on this software must
* also be made publicly available under the terms of the GPL ("Copyleft").
*
* Alternatively, this software may be distributed and modified in conjunction
* with a valid QF/C Quantum Leaps commercial license. Quantum Leaps
* commercial licenses are designed for users who want to retain proprietary
* status of their code. The users who license this software under one of
* Quantum Leaps commercial licenses do not use this software under the GPL
* and therefore are not subject to any of its terms.
*
* Contact information:
* Quantum Leaps Web site:  http://www.quantum-leaps.com
* Quantum Leaps licensing: http://www.quantum-leaps.com/licensing
* Quantum Leaps products:  http://www.quantum-leaps.com/products
* e-mail:                  [e-mail]
*****************************************************************************/
#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              pthread_t

                     /* various QF object sizes configuration for this port */
#define QF_MAX_ACTIVE               63
#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_INT_KEY_TYPE not defined */
#define QF_INT_LOCK(key_)           pthread_mutex_lock(&QF_pThreadMutex_)
#define QF_INT_UNLOCK(key_)         pthread_mutex_unlock(&QF_pThreadMutex_)

                    /* QF scheduler locking/unlocking for Linux, see NOTE02 */
#define QF_SCHED_LOCK()             pthread_mutex_lock(&QF_pThreadMutex_)
#define QF_SCHED_UNLOCK()           pthread_mutex_unlock(&QF_pThreadMutex_)

   /* _GNU_SOURCE gives us access to PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP */
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <pthread.h>
#include <errno.h>
#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 */


/*****************************************************************************
* interface used only inside QF, but not in applications
*/
                                      /* OS-object implementation for Linux */
#define QACTIVE_OSOBJECT_WAIT_(me_) \
    if ((me_)->eQueue__.frontEvt__ == (QEvent const *)0) { \
        do { \
            pthread_cond_wait(&(me_)->osObject__, &QF_pThreadMutex_); \
        } while ((me_)->eQueue__.frontEvt__ == (QEvent const *)0); \
    } else ((void)0)

#define QACTIVE_OSOBJECT_SIGNAL_(me_) \
    QF_INT_UNLOCK_(); \
    Q_ASSERT((me_)->eQueue__.nTot__ != (QEQueueCtr)0); \
    pthread_cond_signal(&(me_)->osObject__)

#define QACTIVE_OSOBJECT_ONIDLE_(me_) ((void)0)

                                        /* native QF event queue operations */
#define QACTIVE_POST_FIFO_(me_, e_) (QActive_postFIFO__((me_), (e_)))
#define QACTIVE_POST_LIFO_(me_, e_) (QActive_postLIFO__((me_), (e_)))
#define QACTIVE_GET_(me_, e_)       ((e_) = QActive_get__(me_))

                                         /* 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_)       ((e_) = (QEvent *)QMPool_get(&(p_)))
#define QF_EPOOL_PUT_(p_, e_)       (QMPool_put(&(p_), e_))

                                  /* mutex used for the QF critical section */
extern pthread_mutex_t QF_pThreadMutex_;
                                      /* flag indicating when QF is running */
extern uint8_t QF_running_;


/*****************************************************************************
*
* 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 shouldnot 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.
*
*
* NOTE02:
* QF uses scheduler locking when it publishes events to multiple subscribers
* and in this port also when QF_tick() is invoked.
*
* The Linux API does not support scheduler locking.
*
* Therefore, this port implements scheduler locking as a critical section,
* which in turn is implemented with the common mutex QF_pThreadMutex_.
*
* Please note that the consequence of using critical section for scheduler
* locking is nesting of critical sections. This means that the common mutex
* QF_pThreadMutex_ must be initialized as a RECURSIVE mutex.
*/

#endif                                                         /* qf_port_h */