www.pudn.com > uCOS-II_MSP430_V11.rar > OS_MBOX.C, change:2002-01-25,size:23801b


/* 
********************************************************************************************************* 
*                                                uC/OS-II 
*                                          The Real-Time Kernel 
*                                       MESSAGE MAILBOX MANAGEMENT 
* 
*                          (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL 
*                                           All Rights Reserved 
* 
* File : OS_MBOX.C 
* By   : Jean J. Labrosse 
********************************************************************************************************* 
*/ 
 
#ifndef  OS_MASTER_FILE 
#include "includes.h" 
#endif 
 
#if OS_MBOX_EN > 0 
/* 
********************************************************************************************************* 
*                                     ACCEPT MESSAGE FROM MAILBOX 
* 
* Description: This function checks the mailbox to see if a message is available.  Unlike OSMboxPend(), 
*              OSMboxAccept() does not suspend the calling task if a message is not available. 
* 
* Arguments  : pevent        is a pointer to the event control block 
* 
* Returns    : != (void *)0  is the message in the mailbox if one is available.  The mailbox is cleared 
*                            so the next time OSMboxAccept() is called, the mailbox will be empty. 
*              == (void *)0  if the mailbox is empty or, 
*                            if 'pevent' is a NULL pointer or, 
*                            if you didn't pass the proper event pointer. 
********************************************************************************************************* 
*/ 
 
#if OS_MBOX_ACCEPT_EN > 0 
void  *OSMboxAccept (OS_EVENT *pevent) 
{ 
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */ 
    OS_CPU_SR  cpu_sr; 
#endif     
    void      *msg; 
 
 
#if OS_ARG_CHK_EN > 0 
    if (pevent == (OS_EVENT *)0) {                        /* Validate 'pevent'                         */ 
        return ((void *)0); 
    } 
    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {      /* Validate event block type                 */ 
        return ((void *)0); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    msg                = pevent->OSEventPtr; 
    pevent->OSEventPtr = (void *)0;                       /* Clear the mailbox                         */ 
    OS_EXIT_CRITICAL(); 
    return (msg);                                         /* Return the message received (or NULL)     */ 
} 
#endif 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                        CREATE A MESSAGE MAILBOX 
* 
* Description: This function creates a message mailbox if free event control blocks are available. 
* 
* Arguments  : msg           is a pointer to a message that you wish to deposit in the mailbox.  If 
*                            you set this value to the NULL pointer (i.e. (void *)0) then the mailbox 
*                            will be considered empty. 
* 
* Returns    : != (OS_EVENT *)0  is a pointer to the event control clock (OS_EVENT) associated with the 
*                                created mailbox 
*              == (OS_EVENT *)0  if no event control blocks were available 
********************************************************************************************************* 
*/ 
 
OS_EVENT  *OSMboxCreate (void *msg) 
{ 
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */ 
    OS_CPU_SR  cpu_sr; 
#endif     
    OS_EVENT  *pevent; 
 
 
    if (OSIntNesting > 0) {                      /* See if called from ISR ...                         */ 
        return ((OS_EVENT *)0);                  /* ... can't CREATE from an ISR                       */ 
    } 
    OS_ENTER_CRITICAL(); 
    pevent = OSEventFreeList;                    /* Get next free event control block                  */ 
    if (OSEventFreeList != (OS_EVENT *)0) {      /* See if pool of free ECB pool was empty             */ 
        OSEventFreeList = (OS_EVENT *)OSEventFreeList->OSEventPtr; 
    } 
    OS_EXIT_CRITICAL(); 
    if (pevent != (OS_EVENT *)0) { 
        pevent->OSEventType = OS_EVENT_TYPE_MBOX; 
        pevent->OSEventCnt  = 0; 
        pevent->OSEventPtr  = msg;               /* Deposit message in event control block             */ 
        OS_EventWaitListInit(pevent); 
    } 
    return (pevent);                             /* Return pointer to event control block              */ 
} 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                         DELETE A MAIBOX 
* 
* Description: This function deletes a mailbox and readies all tasks pending on the mailbox. 
* 
* Arguments  : pevent        is a pointer to the event control block associated with the desired 
*                            mailbox. 
* 
*              opt           determines delete options as follows: 
*                            opt == OS_DEL_NO_PEND   Delete the mailbox ONLY if no task pending 
*                            opt == OS_DEL_ALWAYS    Deletes the mailbox even if tasks are waiting. 
*                                                    In this case, all the tasks pending will be readied. 
* 
*              err           is a pointer to an error code that can contain one of the following values: 
*                            OS_NO_ERR               The call was successful and the mailbox was deleted 
*                            OS_ERR_DEL_ISR          If you attempted to delete the mailbox from an ISR 
*                            OS_ERR_INVALID_OPT      An invalid option was specified 
*                            OS_ERR_TASK_WAITING     One or more tasks were waiting on the mailbox 
*                            OS_ERR_EVENT_TYPE       If you didn't pass a pointer to a mailbox 
*                            OS_ERR_PEVENT_NULL      If 'pevent' is a NULL pointer. 
* 
* Returns    : pevent        upon error 
*              (OS_EVENT *)0 if the mailbox was successfully deleted. 
* 
* Note(s)    : 1) This function must be used with care.  Tasks that would normally expect the presence of 
*                 the mailbox MUST check the return code of OSMboxPend(). 
*              2) OSMboxAccept() callers will not know that the intended mailbox has been deleted! 
*              3) This call can potentially disable interrupts for a long time.  The interrupt disable 
*                 time is directly proportional to the number of tasks waiting on the mailbox. 
*              4) Because ALL tasks pending on the mailbox will be readied, you MUST be careful in 
*                 applications where the mailbox is used for mutual exclusion because the resource(s) 
*                 will no longer be guarded by the mailbox. 
********************************************************************************************************* 
*/ 
 
#if OS_MBOX_DEL_EN > 0 
OS_EVENT  *OSMboxDel (OS_EVENT *pevent, INT8U opt, INT8U *err) 
{ 
#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */ 
    OS_CPU_SR  cpu_sr; 
#endif     
    BOOLEAN    tasks_waiting; 
 
 
    if (OSIntNesting > 0) {                                /* See if called from ISR ...               */ 
        *err = OS_ERR_DEL_ISR;                             /* ... can't DELETE from an ISR             */ 
        return (pevent); 
    } 
#if OS_ARG_CHK_EN > 0 
    if (pevent == (OS_EVENT *)0) {                         /* Validate 'pevent'                        */ 
        *err = OS_ERR_PEVENT_NULL; 
        return (pevent); 
    } 
    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {       /* Validate event block type                */ 
        *err = OS_ERR_EVENT_TYPE; 
        return (pevent); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    if (pevent->OSEventGrp != 0x00) {                      /* See if any tasks waiting on mailbox      */ 
        tasks_waiting = TRUE;                              /* Yes                                      */ 
    } else { 
        tasks_waiting = FALSE;                             /* No                                       */ 
    } 
    switch (opt) { 
        case OS_DEL_NO_PEND:                               /* Delete mailbox only if no task waiting   */ 
             if (tasks_waiting == FALSE) { 
                 pevent->OSEventType = OS_EVENT_TYPE_UNUSED; 
                 pevent->OSEventPtr  = OSEventFreeList;    /* Return Event Control Block to free list  */ 
                 OSEventFreeList     = pevent;             /* Get next free event control block        */ 
                 OS_EXIT_CRITICAL(); 
                 *err = OS_NO_ERR; 
                 return ((OS_EVENT *)0);                   /* Mailbox has been deleted                 */ 
             } else { 
                 OS_EXIT_CRITICAL(); 
                 *err = OS_ERR_TASK_WAITING; 
                 return (pevent); 
             } 
 
        case OS_DEL_ALWAYS:                                /* Always delete the mailbox                */ 
             while (pevent->OSEventGrp != 0x00) {          /* Ready ALL tasks waiting for mailbox      */ 
                 OS_EventTaskRdy(pevent, (void *)0, OS_STAT_MBOX); 
             } 
             pevent->OSEventType = OS_EVENT_TYPE_UNUSED; 
             pevent->OSEventPtr  = OSEventFreeList;        /* Return Event Control Block to free list  */ 
             OSEventFreeList     = pevent;                 /* Get next free event control block        */ 
             OS_EXIT_CRITICAL(); 
             if (tasks_waiting == TRUE) {                  /* Reschedule only if task(s) were waiting  */ 
                 OS_Sched();                               /* Find highest priority task ready to run  */ 
             } 
             *err = OS_NO_ERR; 
             return ((OS_EVENT *)0);                       /* Mailbox has been deleted                 */ 
 
        default: 
             OS_EXIT_CRITICAL(); 
             *err = OS_ERR_INVALID_OPT; 
             return (pevent); 
    } 
} 
#endif 
 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                      PEND ON MAILBOX FOR A MESSAGE 
* 
* Description: This function waits for a message to be sent to a mailbox 
* 
* Arguments  : pevent        is a pointer to the event control block associated with the desired mailbox 
* 
*              timeout       is an optional timeout period (in clock ticks).  If non-zero, your task will 
*                            wait for a message to arrive at the mailbox up to the amount of time 
*                            specified by this argument.  If you specify 0, however, your task will wait 
*                            forever at the specified mailbox or, until a message arrives. 
* 
*              err           is a pointer to where an error message will be deposited.  Possible error 
*                            messages are: 
* 
*                            OS_NO_ERR           The call was successful and your task received a 
*                                                message. 
*                            OS_TIMEOUT          A message was not received within the specified timeout 
*                            OS_ERR_EVENT_TYPE   Invalid event type 
*                            OS_ERR_PEND_ISR     If you called this function from an ISR and the result 
*                                                would lead to a suspension. 
*                            OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer 
* 
* Returns    : != (void *)0  is a pointer to the message received 
*              == (void *)0  if no message was received or, 
*                            if 'pevent' is a NULL pointer or, 
*                            if you didn't pass the proper pointer to the event control block. 
********************************************************************************************************* 
*/ 
 
void  *OSMboxPend (OS_EVENT *pevent, INT16U timeout, INT8U *err) 
{ 
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */ 
    OS_CPU_SR  cpu_sr; 
#endif     
    void      *msg; 
 
 
    if (OSIntNesting > 0) {                           /* See if called from ISR ...                    */ 
        *err = OS_ERR_PEND_ISR;                       /* ... can't PEND from an ISR                    */ 
        return ((void *)0); 
    } 
#if OS_ARG_CHK_EN > 0 
    if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */ 
        *err = OS_ERR_PEVENT_NULL; 
        return ((void *)0); 
    } 
    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {  /* Validate event block type                     */ 
        *err = OS_ERR_EVENT_TYPE; 
        return ((void *)0); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    msg = pevent->OSEventPtr; 
    if (msg != (void *)0) {                           /* See if there is already a message             */ 
        pevent->OSEventPtr = (void *)0;               /* Clear the mailbox                             */ 
        OS_EXIT_CRITICAL(); 
        *err = OS_NO_ERR; 
        return (msg);                                 /* Return the message received (or NULL)         */ 
    } 
    OSTCBCur->OSTCBStat |= OS_STAT_MBOX;              /* Message not available, task will pend         */ 
    OSTCBCur->OSTCBDly   = timeout;                   /* Load timeout in TCB                           */ 
    OS_EventTaskWait(pevent);                         /* Suspend task until event or timeout occurs    */ 
    OS_EXIT_CRITICAL(); 
    OS_Sched();                                       /* Find next highest priority task ready to run  */ 
    OS_ENTER_CRITICAL(); 
    msg = OSTCBCur->OSTCBMsg; 
    if (msg != (void *)0) {                           /* See if we were given the message              */ 
        OSTCBCur->OSTCBMsg      = (void *)0;          /* Yes, clear message received                   */ 
        OSTCBCur->OSTCBStat     = OS_STAT_RDY; 
        OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0;      /* No longer waiting for event                   */ 
        OS_EXIT_CRITICAL(); 
        *err                    = OS_NO_ERR; 
        return (msg);                                 /* Return the message received                   */ 
    } 
    OS_EventTO(pevent);                               /* Timed out, Make task ready                    */ 
    OS_EXIT_CRITICAL(); 
    *err = OS_TIMEOUT;                                /* Indicate that a timeout occured               */ 
    return ((void *)0);                               /* Return a NULL message                         */ 
} 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                       POST MESSAGE TO A MAILBOX 
* 
* Description: This function sends a message to a mailbox 
* 
* Arguments  : pevent        is a pointer to the event control block associated with the desired mailbox 
* 
*              msg           is a pointer to the message to send.  You MUST NOT send a NULL pointer. 
* 
* Returns    : OS_NO_ERR            The call was successful and the message was sent 
*              OS_MBOX_FULL         If the mailbox already contains a message.  You can can only send one 
*                                   message at a time and thus, the message MUST be consumed before you 
*                                   are allowed to send another one. 
*              OS_ERR_EVENT_TYPE    If you are attempting to post to a non mailbox. 
*              OS_ERR_PEVENT_NULL   If 'pevent' is a NULL pointer 
*              OS_ERR_POST_NULL_PTR If you are attempting to post a NULL pointer 
********************************************************************************************************* 
*/ 
 
#if OS_MBOX_POST_EN > 0 
INT8U  OSMboxPost (OS_EVENT *pevent, void *msg) 
{ 
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */ 
    OS_CPU_SR  cpu_sr; 
#endif     
     
     
#if OS_ARG_CHK_EN > 0 
    if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */ 
        return (OS_ERR_PEVENT_NULL); 
    } 
    if (msg == (void *)0) {                           /* Make sure we are not posting a NULL pointer   */ 
        return (OS_ERR_POST_NULL_PTR); 
    } 
    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {  /* Validate event block type                     */ 
        return (OS_ERR_EVENT_TYPE); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    if (pevent->OSEventGrp != 0x00) {                 /* See if any task pending on mailbox            */ 
        OS_EventTaskRdy(pevent, msg, OS_STAT_MBOX);   /* Ready highest priority task waiting on event  */ 
        OS_EXIT_CRITICAL(); 
        OS_Sched();                                   /* Find highest priority task ready to run       */ 
        return (OS_NO_ERR); 
    } 
    if (pevent->OSEventPtr != (void *)0) {            /* Make sure mailbox doesn't already have a msg  */ 
        OS_EXIT_CRITICAL(); 
        return (OS_MBOX_FULL); 
    } 
    pevent->OSEventPtr = msg;                         /* Place message in mailbox                      */ 
    OS_EXIT_CRITICAL(); 
    return (OS_NO_ERR); 
} 
#endif 
 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                       POST MESSAGE TO A MAILBOX 
* 
* Description: This function sends a message to a mailbox 
* 
* Arguments  : pevent        is a pointer to the event control block associated with the desired mailbox 
* 
*              msg           is a pointer to the message to send.  You MUST NOT send a NULL pointer. 
* 
*              opt           determines the type of POST performed: 
*                            OS_POST_OPT_NONE         POST to a single waiting task  
*                                                     (Identical to OSMboxPost()) 
*                            OS_POST_OPT_BROADCAST    POST to ALL tasks that are waiting on the mailbox 
* 
* Returns    : OS_NO_ERR            The call was successful and the message was sent 
*              OS_MBOX_FULL         If the mailbox already contains a message.  You can can only send one 
*                                   message at a time and thus, the message MUST be consumed before you 
*                                   are allowed to send another one. 
*              OS_ERR_EVENT_TYPE    If you are attempting to post to a non mailbox. 
*              OS_ERR_PEVENT_NULL   If 'pevent' is a NULL pointer 
*              OS_ERR_POST_NULL_PTR If you are attempting to post a NULL pointer 
* 
* Warning    : Interrupts can be disabled for a long time if you do a 'broadcast'.  In fact, the  
*              interrupt disable time is proportional to the number of tasks waiting on the mailbox. 
********************************************************************************************************* 
*/ 
 
#if OS_MBOX_POST_OPT_EN > 0 
INT8U  OSMboxPostOpt (OS_EVENT *pevent, void *msg, INT8U opt) 
{ 
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */ 
    OS_CPU_SR  cpu_sr; 
#endif     
     
     
#if OS_ARG_CHK_EN > 0 
    if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */ 
        return (OS_ERR_PEVENT_NULL); 
    } 
    if (msg == (void *)0) {                           /* Make sure we are not posting a NULL pointer   */ 
        return (OS_ERR_POST_NULL_PTR); 
    } 
    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {  /* Validate event block type                     */ 
        return (OS_ERR_EVENT_TYPE); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    if (pevent->OSEventGrp != 0x00) {                 /* See if any task pending on mailbox            */ 
        if ((opt & OS_POST_OPT_BROADCAST) != 0x00) {  /* Do we need to post msg to ALL waiting tasks ? */ 
            while (pevent->OSEventGrp != 0x00) {      /* Yes, Post to ALL tasks waiting on mailbox     */            
                OS_EventTaskRdy(pevent, msg, OS_STAT_MBOX);     
            } 
        } else { 
            OS_EventTaskRdy(pevent, msg, OS_STAT_MBOX);    /* No,  Post to HPT waiting on mbox         */ 
        } 
        OS_EXIT_CRITICAL(); 
        OS_Sched();                                        /* Find highest priority task ready to run  */ 
        return (OS_NO_ERR); 
    } 
    if (pevent->OSEventPtr != (void *)0) {            /* Make sure mailbox doesn't already have a msg  */ 
        OS_EXIT_CRITICAL(); 
        return (OS_MBOX_FULL); 
    } 
    pevent->OSEventPtr = msg;                         /* Place message in mailbox                      */ 
    OS_EXIT_CRITICAL(); 
    return (OS_NO_ERR); 
} 
#endif 
 
/*$PAGE*/ 
/* 
********************************************************************************************************* 
*                                        QUERY A MESSAGE MAILBOX 
* 
* Description: This function obtains information about a message mailbox. 
* 
* Arguments  : pevent        is a pointer to the event control block associated with the desired mailbox 
* 
*              pdata         is a pointer to a structure that will contain information about the message 
*                            mailbox. 
* 
* Returns    : OS_NO_ERR           The call was successful and the message was sent 
*              OS_ERR_EVENT_TYPE   If you are attempting to obtain data from a non mailbox. 
*              OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer 
********************************************************************************************************* 
*/ 
 
#if OS_MBOX_QUERY_EN > 0 
INT8U  OSMboxQuery (OS_EVENT *pevent, OS_MBOX_DATA *pdata) 
{ 
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */ 
    OS_CPU_SR  cpu_sr; 
#endif     
    INT8U     *psrc; 
    INT8U     *pdest; 
 
 
#if OS_ARG_CHK_EN > 0 
    if (pevent == (OS_EVENT *)0) {                         /* Validate 'pevent'                        */ 
        return (OS_ERR_PEVENT_NULL); 
    } 
    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {       /* Validate event block type                */ 
        return (OS_ERR_EVENT_TYPE); 
    } 
#endif 
    OS_ENTER_CRITICAL(); 
    pdata->OSEventGrp = pevent->OSEventGrp;                /* Copy message mailbox wait list           */ 
    psrc              = &pevent->OSEventTbl[0]; 
    pdest             = &pdata->OSEventTbl[0]; 
 
#if OS_EVENT_TBL_SIZE > 0 
    *pdest++          = *psrc++; 
#endif 
 
#if OS_EVENT_TBL_SIZE > 1 
    *pdest++          = *psrc++; 
#endif 
 
#if OS_EVENT_TBL_SIZE > 2 
    *pdest++          = *psrc++; 
#endif 
 
#if OS_EVENT_TBL_SIZE > 3 
    *pdest++          = *psrc++; 
#endif 
 
#if OS_EVENT_TBL_SIZE > 4 
    *pdest++          = *psrc++; 
#endif 
 
#if OS_EVENT_TBL_SIZE > 5 
    *pdest++          = *psrc++; 
#endif 
 
#if OS_EVENT_TBL_SIZE > 6 
    *pdest++          = *psrc++; 
#endif 
 
#if OS_EVENT_TBL_SIZE > 7 
    *pdest            = *psrc; 
#endif 
    pdata->OSMsg = pevent->OSEventPtr;                     /* Get message from mailbox                 */ 
    OS_EXIT_CRITICAL(); 
    return (OS_NO_ERR); 
} 
#endif                                                     /* OS_MBOX_QUERY_EN                         */ 
#endif                                                     /* OS_MBOX_EN                               */