root / Whitix / branches / hybrid / include / wait.h

/*  This file is part of Whitix.
 *
 *  Whitix is free 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  Whitix 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 Whitix; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#ifndef WAIT_H
#define WAIT_H

#include <llist.h>
#include <sched.h>
#include <typedefs.h>

/* Uncomment this if you'd like to investigate strange wait-queue behaviour. */
/* #define WAIT_DEBUG */

struct WaitQueueTag
{
        struct ListHead list;
        Spinlock spinLock;
};

typedef struct WaitQueueTag WaitQueue;

#define DECLARE_WAITQUEUE_HEAD(waitQueue) \
        WaitQueue waitQueue={LIST_HEAD_INIT((waitQueue).list),{0}}

#define INIT_WAITQUEUE_HEAD(waitQueue) \
        do { INIT_LIST_HEAD(&((waitQueue)->list)); (waitQueue)->spinLock.flags=0; } while (0)

struct WaitQueueEntry
{
        struct Thread* thread;
        struct ListHead next;

#ifdef WAIT_DEBUG
        unsigned int magic;
#endif

};

static inline void WaitAddToQueue(WaitQueue* waitQueue,struct WaitQueueEntry* waitEntry)
{
        SpinLockIrq(&waitQueue->spinLock);

#ifdef WAIT_DEBUG
        waitEntry->magic = 0xDEADBEEF;
#endif

        ListAdd(&waitEntry->next,&waitQueue->list);
        SpinUnlockIrq(&waitQueue->spinLock);
}

static inline void WaitRemoveFromQueue(WaitQueue* waitQueue,struct WaitQueueEntry* waitEntry)
{
        SpinLockIrq(&waitQueue->spinLock);

        ListRemove(&waitEntry->next);

#ifdef WAIT_DEBUG
        if (waitEntry->magic != 0xDEADBEEF) printf("Remove error!, %#X\n",waitEntry->magic);
#endif


        SpinUnlockIrq(&waitQueue->spinLock);
}

#define WAIT_ON(waitQueue,condition) \
do{ \
        if ((condition)) \
                break; \
        struct WaitQueueEntry waitEntry={currThread,{NULL,NULL}}; \
        ThrGetThread(currThread); \
        while (1) { \
                if ((condition)) break; \
                WaitAddToQueue(&(waitQueue),&waitEntry); \
                ThrSuspendThread(currThread); \
                ThrSchedule(); /* Will return here when the thread is scheduled again */ \
                WaitRemoveFromQueue(&(waitQueue),&waitEntry); \
        } \
        ThrReleaseThread(currThread); \
}while(0)

void WakeUp(WaitQueue* waitQueue);

#endif