/*

*********************************************************************************************************

*                                                uC/OS-II

*                                          The Real-Time Kernel

*                                       MESSAGE MAILBOX MANAGEMENT

*

*                          (c) Copyright 1992-2005, Jean J. Labrosse, Weston, FL

*                                           All Rights Reserved

*

* File    : OS_MBOX.C

* By      : Jean J. Labrosse

* Version : V2.80

*********************************************************************************************************

*/



#ifndef  OS_MASTER_FILE

#include <ucos_ii.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)

{

    void      *msg;

#if OS_CRITICAL_METHOD == 3                               /* Allocate storage for CPU status register  */

    OS_CPU_SR  cpu_sr = 0;

#endif







#if OS_ARG_CHK_EN > 0

    if (pevent == (OS_EVENT *)0) {                        /* Validate 'pevent'                         */

        return ((void *)0);

    }

#endif

    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {      /* Validate event block type                 */

        return ((void *)0);

    }

    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)

{

    OS_EVENT  *pevent;

#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */

    OS_CPU_SR  cpu_sr = 0;

#endif







    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             */

#if OS_EVENT_NAME_SIZE > 1

        pevent->OSEventName[0] = '?';

        pevent->OSEventName[1] = OS_ASCII_NUL;

#endif

        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)

{

    BOOLEAN    tasks_waiting;

    OS_EVENT  *pevent_return;

#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */

    OS_CPU_SR  cpu_sr = 0;

#endif







#if OS_ARG_CHK_EN > 0

    if (err == (INT8U *)0) {                               /* Validate 'err'                           */

        return (pevent);

    }

    if (pevent == (OS_EVENT *)0) {                         /* Validate 'pevent'                        */

        *err = OS_ERR_PEVENT_NULL;

        return (pevent);

    }

#endif

    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {       /* Validate event block type                */

        *err = OS_ERR_EVENT_TYPE;

        return (pevent);

    }

    if (OSIntNesting > 0) {                                /* See if called from ISR ...               */

        *err = OS_ERR_DEL_ISR;                             /* ... can't DELETE from an ISR             */

        return (pevent);

    }

    OS_ENTER_CRITICAL();

    if (pevent->OSEventGrp != 0) {                         /* 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) {

#if OS_EVENT_NAME_SIZE > 1

                 pevent->OSEventName[0] = '?';             /* Unknown name                             */

                 pevent->OSEventName[1] = OS_ASCII_NUL;

#endif

                 pevent->OSEventType = OS_EVENT_TYPE_UNUSED;

                 pevent->OSEventPtr  = OSEventFreeList;    /* Return Event Control Block to free list  */

                 pevent->OSEventCnt  = 0;

                 OSEventFreeList     = pevent;             /* Get next free event control block        */

                 OS_EXIT_CRITICAL();

                 *err                = OS_NO_ERR;

                 pevent_return       = (OS_EVENT *)0;      /* Mailbox has been deleted                 */

             } else {

                 OS_EXIT_CRITICAL();

                 *err                = OS_ERR_TASK_WAITING;

                 pevent_return       = pevent;

             }

             break;



        case OS_DEL_ALWAYS:                                /* Always delete the mailbox                */

             while (pevent->OSEventGrp != 0) {             /* Ready ALL tasks waiting for mailbox      */

                 (void)OS_EventTaskRdy(pevent, (void *)0, OS_STAT_MBOX);

             }

#if OS_EVENT_NAME_SIZE > 1

             pevent->OSEventName[0] = '?';                 /* Unknown name                             */

             pevent->OSEventName[1] = OS_ASCII_NUL;

#endif

             pevent->OSEventType    = OS_EVENT_TYPE_UNUSED;

             pevent->OSEventPtr     = OSEventFreeList;     /* Return Event Control Block to free list  */

             pevent->OSEventCnt     = 0;

             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;

             pevent_return = (OS_EVENT *)0;                /* Mailbox has been deleted                 */

             break;



        default:

             OS_EXIT_CRITICAL();

             *err          = OS_ERR_INVALID_OPT;

             pevent_return = pevent;

             break;

    }

    return (pevent_return);

}

#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)

{

    void      *msg;

#if OS_CRITICAL_METHOD == 3                           /* Allocate storage for CPU status register      */

    OS_CPU_SR  cpu_sr = 0;

#endif







#if OS_ARG_CHK_EN > 0

    if (err == (INT8U *)0) {                          /* Validate 'err'                                */

        return ((void *)0);

    }

    if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */

        *err = OS_ERR_PEVENT_NULL;

        return ((void *)0);

    }

#endif

    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {  /* Validate event block type                     */

        *err = OS_ERR_EVENT_TYPE;

        return ((void *)0);

    }

    if (OSIntNesting > 0) {                           /* See if called from ISR ...                    */

        *err = OS_ERR_PEND_ISR;                       /* ... can't PEND from an ISR                    */

        return ((void *)0);

    }

    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->OSTCBPendTO = FALSE;

    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();

    if (OSTCBCur->OSTCBPendTO == TRUE) {              /* See if we were given the message              */

        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                         */

    }

    msg                     = OSTCBCur->OSTCBMsg;

    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                   */

}

/*$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

*

* Note(s)    : 1) HPT means Highest Priority Task

*********************************************************************************************************

*/



#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 = 0;

#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);

    }

#endif

    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {  /* Validate event block type                     */

        return (OS_ERR_EVENT_TYPE);

    }

    OS_ENTER_CRITICAL();

    if (pevent->OSEventGrp != 0) {                        /* See if any task pending on mailbox        */

        (void)OS_EventTaskRdy(pevent, msg, OS_STAT_MBOX); /* Ready HPT 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

*

* Note(s)    : 1) HPT means Highest Priority Task

*

* 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 = 0;

#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);

    }

#endif

    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {  /* Validate event block type                     */

        return (OS_ERR_EVENT_TYPE);

    }

    OS_ENTER_CRITICAL();

    if (pevent->OSEventGrp != 0) {                    /* 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 != 0) {         /* Yes, Post to ALL tasks waiting on mailbox     */

                (void)OS_EventTaskRdy(pevent, msg, OS_STAT_MBOX);

            }

        } else {

            (void)OS_EventTaskRdy(pevent, msg, OS_STAT_MBOX);  /* No,  Post to HPT waiting on mbox     */

        }

        OS_EXIT_CRITICAL();

        OS_Sched();                                            /* Find HPT 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

*

*              p_mbox_data   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

*              OS_ERR_PDATA_NULL   If 'p_mbox_data' is a NULL pointer

*********************************************************************************************************

*/



#if OS_MBOX_QUERY_EN > 0

INT8U  OSMboxQuery (OS_EVENT *pevent, OS_MBOX_DATA *p_mbox_data)

{

    INT8U      i;

#if OS_LOWEST_PRIO <= 63

    INT8U     *psrc;

    INT8U     *pdest;

#else

    INT16U    *psrc;

    INT16U    *pdest;

#endif

#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */

    OS_CPU_SR  cpu_sr = 0;

#endif







#if OS_ARG_CHK_EN > 0

    if (pevent == (OS_EVENT *)0) {                         /* Validate 'pevent'                        */

        return (OS_ERR_PEVENT_NULL);

    }

    if (p_mbox_data == (OS_MBOX_DATA *)0) {                /* Validate 'p_mbox_data'                   */

        return (OS_ERR_PDATA_NULL);

    }

#endif

    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {       /* Validate event block type                */

        return (OS_ERR_EVENT_TYPE);

    }

    OS_ENTER_CRITICAL();

    p_mbox_data->OSEventGrp = pevent->OSEventGrp;          /* Copy message mailbox wait list           */

    psrc                    = &pevent->OSEventTbl[0];

    pdest                   = &p_mbox_data->OSEventTbl[0];

    for (i = 0; i < OS_EVENT_TBL_SIZE; i++) {

        *pdest++ = *psrc++;

    }

    p_mbox_data->OSMsg = pevent->OSEventPtr;               /* Get message from mailbox                 */

    OS_EXIT_CRITICAL();

    return (OS_NO_ERR);

}

#endif                                                     /* OS_MBOX_QUERY_EN                         */

#endif                                                     /* OS_MBOX_EN                               */