mailbox.c

Bycore是一个嵌入式操作系统内核。Bycore包括内存管理、任务管理、中断管理、任务互斥、同步与通信管理等功能。Bycore全部由C语言完成

/**
 *  mailbox.c - Related routines of mailbox.
 *
 *  Copyright (C) 2008  ZhangHu
 *  All rights reserved.
 *  E-MAIL: [e-mail]
 *
 *  This program 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  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/>.
 */


#include "include/types.h"
#include "include/mem.h"
#include "include/core.h"
#include "include/mailbox.h"
#include "include/irq.h"


/**
 * mboxInit - It creates a new mailbox.
 * @Size: The size of mailbox.
 * @return: The start address of new mailbox.
 *
 * @notes:
 */
mail_t *mboxInit(uword_t Size) {
    mail_t *pmail;
    msg_t *pmsg;

    if((pmail = (mail_t*)kmalloc(sizeof(mail_t))) == NULL) {
        return NULL;
    }
    if((pmsg = (msg_t*)kmalloc(Size *sizeof(msg_t))) == NULL) {
        kfree(pmail);
        return NULL;
    }
    kmemset(pmail, 0, sizeof(mail_t));
    kmemset(pmsg, 0, Size *sizeof(msg_t));

    pmsg->key_id = 0;
    pmsg->rev_id = 0;
    pmsg->send_id = 0;
    pmsg->pmsg = NULL;

    pmail->size = Size;
    pmail->used = 0;
    pmail->start = pmsg;
    pmail->end = &pmsg[Size - 1];
    pmail->pos = pmsg;
    return pmail;
}

/**
 * mboxSend - Sending a message to a mailbox.
 * @pMial: Pointer to the mailbox.
 * @Key: Serial number of message.
 * @RevID: ID of Receiving task.
 * @pMsg: Pointer to the message.
 * @err: It will return rusults or reasons about this operation.
 * @return: TURE if successful, otherwise FALSE;
 *
 * @notes:
 */
uword_t mboxSend(mail_t *pMail, uword_t Key, uword_t RevID,
                 void *pMsg, uword_t *err) {
    msg_t *pmark;

    if(pMail == NULL) {
        *err = MAILBOX_NOT_EXIST;
        return FALSE;
    }

    mac_disable_irq();
    if(pMail->size == pMail->used) {
        *err = MAILBOX_FULL;
        mac_enable_irq();
        return FALSE;
    }

    pmark = pMail->pos;
    do {
        if(pMail->pos->pmsg == NULL) {
            break;
        } else if(pMail->pos++ == pMail->end) {
            pMail->pos = pMail->start;
        }
    } while(pMail->pos != pmark);

    pMail->pos->key_id = Key;
    pMail->pos->send_id = current()->id;
    pMail->pos->rev_id = RevID;
    pMail->pos->pmsg = pMsg;
    pMail->used++;
    *err = MAILBOX_OK;
    mac_enable_irq();
    return TRUE;
}

/**
 * mboxRev - Retrieve message from mailbox.
 * @pMail: Pointer to the mailbox.
 * @Key: Serial number of message.
 * @SendID: ID of sending task.
 * @err: It will return rusults or reasons about this operation.
 * @return: The message if successful, NULL for failed.
 *
 * @notes:
 */
void *mboxRev(mail_t *pMail, uword_t Key, uword_t SendID, uword_t *err) {
    msg_t *pmark;
    void *remsg;

    if(pMail == NULL) {
        *err = MAILBOX_NOT_EXIST;
        return NULL;
    }

    mac_disable_irq();
    if(pMail->used == 0) {
        *err = MAILBOX_EMPTY;
        mac_enable_irq();
        return NULL;
    }

    /* check message */
    pmark = pMail->pos;
    do {
        if(pMail->pos->pmsg != NULL &&  \
            pMail->pos->key_id == Key &&  \
            pMail->pos->send_id == SendID &&  \
            pMail->pos->rev_id == current()->id) {

            remsg = pMail->pos->pmsg;

            pMail->pos->key_id = 0;
            pMail->pos->send_id = 0;
            pMail->pos->rev_id = 0;
            pMail->pos->pmsg = NULL;

            pMail->used--;
            *err = MAILBOX_OK;
            mac_enable_irq();
            return remsg;
        } else if(pMail->pos++ == pMail->end) {
            pMail->pos = pMail->start;
        }
    } while(pMail->pos != pmark);

    *err = MAILBOX_NOT_FOUND_MSG;
    mac_enable_irq();
    return NULL;
}

/**
 * mboxClear - Clear a mailbox.
 * @pMail: Pointer to the mailbox.
 * @return:
 *
 * @notes:
 */
void mboxClear(mail_t *pMail) {
    pMail->used = 0;
    pMail->pos = pMail->start;
}

/**
 * mboxDel - Delete a mailbox.
 * @pMail: Pointer to the mailbox.
 * @return:
 *
 * @notes:
 */
void mboxDel(mail_t *pMail) {
    kfree(pMail->start);
    kfree(pMail);
}