os_task.c

UCOS-III

#if OS_CFG_ISR_POST_DEFERRED_EN > 0u
    if (prio == (OS_PRIO)0) {
        if (p_tcb != &OSIntQTaskTCB) {
            *p_err = OS_ERR_PRIO_INVALID;                   /* Not allowed to use priority 0                          */
            return;
        }
    }
#endif

    if (prio == (OS_CFG_PRIO_MAX - 1u)) {
        if (p_tcb != &OSIdleTaskTCB) {
            *p_err = OS_ERR_PRIO_INVALID;                   /* Not allowed to use same priority as idle task          */
            return;
        }
    }

    OS_TaskInitTCB(p_tcb);                                  /* Initialize the TCB to default values                   */

    *p_err = OS_ERR_NONE;
                                                            /* --------------- CLEAR THE TASK'S STACK --------------- */
    if ((opt & OS_OPT_TASK_STK_CHK) != (OS_OPT)0) {         /* See if stack checking has been enabled                 */
        if ((opt & OS_OPT_TASK_STK_CLR) != (OS_OPT)0) {     /* See if stack needs to be cleared                       */
            p_sp = p_stk_base;
            for (i = 0u; i < stk_size; i++) {               /* Stack grows from HIGH to LOW memory                    */
                *p_sp = (CPU_STK)0;                         /* Clear from bottom of stack and up!                     */
                p_sp++;
            }
        }
    }
                                                            /* ------- INITIALIZE THE STACK FRAME OF THE TASK ------- */
#if (CPU_CFG_STK_GROWTH == CPU_STK_GROWTH_HI_TO_LO)
    p_stk_limit = p_stk_base + stk_limit;
#else
    p_stk_limit = p_stk_base + (stk_size - 1u) - stk_limit;
#endif

    p_sp = OSTaskStkInit(p_task,
                         p_arg,
                         p_stk_base,
                         p_stk_limit,
                         stk_size,
                         opt);

                                                            /* -------------- INITIALIZE THE TCB FIELDS ------------- */
    p_tcb->TaskEntryAddr = p_task;                          /* Save task entry point address                          */
    p_tcb->TaskEntryArg  = p_arg;                           /* Save task entry argument                               */

    p_tcb->NamePtr       = p_name;                          /* Save task name                                         */

    p_tcb->Prio          = prio;                            /* Save the task's priority                               */

    p_tcb->StkPtr        = p_sp;                            /* Save the new top-of-stack pointer                      */
    p_tcb->StkLimitPtr   = p_stk_limit;                     /* Save the stack limit pointer                           */

    p_tcb->TimeQuanta    = time_quanta;                     /* Save the #ticks for time slice (0 means not sliced)    */
#if OS_CFG_SCHED_ROUND_ROBIN_EN > 0u
    if (time_quanta == (OS_TICK)0) {
        p_tcb->TimeQuantaCtr = OSSchedRoundRobinDfltTimeQuanta;
    } else {
        p_tcb->TimeQuantaCtr = time_quanta;
    }
#endif
    p_tcb->ExtPtr        = p_ext;                           /* Save pointer to TCB extension                          */
    p_tcb->StkBasePtr    = p_stk_base;                      /* Save pointer to the base address of the stack          */
    p_tcb->StkSize       = stk_size;                        /* Save the stack size (in number of CPU_STK elements)    */
    p_tcb->Opt           = opt;                             /* Save task options                                      */

#if OS_CFG_TASK_REG_TBL_SIZE > 0u
    for (reg_nbr = 0u; reg_nbr < OS_CFG_TASK_REG_TBL_SIZE; reg_nbr++) {
        p_tcb->RegTbl[reg_nbr] = (OS_REG)0;
    }
#endif

#if OS_CFG_TASK_Q_EN > 0u
    OS_MsgQInit(&p_tcb->MsgQ,                               /* Initialize the task's message queue                    */
                q_size);
#endif

    OSTaskCreateHook(p_tcb);                                /* Call user defined hook                                 */

                                                            /* --------------- ADD TASK TO READY LIST --------------- */
    OS_CRITICAL_ENTER();
    OS_PrioInsert(p_tcb->Prio);
    OS_RdyListInsertTail(p_tcb);

#if OS_CFG_DBG_EN > 0u
    OS_TaskDbgListAdd(p_tcb);
#endif

    OSTaskQty++;                                            /* Increment the #tasks counter                           */

    if (OSRunning != OS_STATE_OS_RUNNING) {                 /* Return if multitasking has not started                 */
        OS_CRITICAL_EXIT();
        return;
    }

    OS_CRITICAL_EXIT_NO_SCHED();

    OSSched();
}

/*$PAGE*/
/*
************************************************************************************************************************
*                                                     DELETE A TASK
*
* Description: This function allows you to delete a task.  The calling task can delete itself by specifying a NULL
*              pointer for 'p_tcb'.  The deleted task is returned to the dormant state and can be re-activated by
*              creating the deleted task again.
*
* Arguments  : p_tcb      is the TCB of the tack to delete
*
*              p_err      is a pointer to an error code returned by this function:
*
*                             OS_ERR_NONE                  if the call is successful
*                             OS_ERR_STATE_INVALID         if the state of the task is invalid
*                             OS_ERR_TASK_DEL_IDLE         if you attempted to delete uC/OS-III's idle task
*                             OS_ERR_TASK_DEL_INVALID      if you attempted to delete uC/OS-III's ISR handler task
*                             OS_ERR_TASK_DEL_ISR          if you tried to delete a task from an ISR
************************************************************************************************************************
*/

#if OS_CFG_TASK_DEL_EN > 0u
void  OSTaskDel (OS_TCB  *p_tcb,
                 OS_ERR  *p_err)
{
    CPU_SR_ALLOC();



#ifdef OS_SAFETY_CRITICAL
    if (p_err == (OS_ERR *)0) {
        OS_SAFETY_CRITICAL_EXCEPTION();
        return;
    }
#endif

#if OS_CFG_CALLED_FROM_ISR_CHK_EN > 0u
    if (OSIntNestingCtr > (OS_NESTING_CTR)0) {              /* See if trying to delete from ISR                       */
       *p_err = OS_ERR_TASK_DEL_ISR;
        return;
    }
#endif

    if (p_tcb == &OSIdleTaskTCB) {                          /* Not allowed to delete the idle task                    */
        *p_err = OS_ERR_TASK_DEL_IDLE;
        return;
    }

#if OS_CFG_ISR_POST_DEFERRED_EN > 0u
    if (p_tcb == &OSIntQTaskTCB) {                          /* Cannot delete the ISR handler task                     */
        *p_err = OS_ERR_TASK_DEL_INVALID;
        return;
    }
#endif

    if (p_tcb == (OS_TCB *)0) {                             /* Delete 'Self'?                                         */
        CPU_CRITICAL_ENTER();
        p_tcb  = OSTCBCurPtr;                               /* Yes.                                                   */
        CPU_CRITICAL_EXIT();
    }

    OS_CRITICAL_ENTER();
    switch (p_tcb->TaskState) {
        case OS_TASK_STATE_RDY:
             OS_RdyListRemove(p_tcb);
             break;

        case OS_TASK_STATE_SUSPENDED:
             break;

        case OS_TASK_STATE_DLY:                             /* Task is only delayed, not on any wait list             */
        case OS_TASK_STATE_DLY_SUSPENDED:
             OS_TickListRemove(p_tcb);
             break;

        case OS_TASK_STATE_PEND:
        case OS_TASK_STATE_PEND_SUSPENDED:
        case OS_TASK_STATE_PEND_TIMEOUT:
        case OS_TASK_STATE_PEND_TIMEOUT_SUSPENDED:
             OS_TickListRemove(p_tcb);
             switch (p_tcb->PendOn) {                       /* See what we are pending on                             */
                 case OS_TASK_PEND_ON_NOTHING:
                 case OS_TASK_PEND_ON_TASK_Q:               /* There is no wait list for these two                    */
                 case OS_TASK_PEND_ON_TASK_SEM:
                      break;

                 case OS_TASK_PEND_ON_FLAG:                 /* Remove from wait list                                  */
                 case OS_TASK_PEND_ON_MULTI:
                 case OS_TASK_PEND_ON_MUTEX:
                 case OS_TASK_PEND_ON_Q:
                 case OS_TASK_PEND_ON_SEM:
                      OS_PendListRemove(p_tcb);
                      break;

                 default:
                      break;
             }
             break;

        default:
            OS_CRITICAL_EXIT();
            *p_err = OS_ERR_STATE_INVALID;
            return;
    }

#if OS_CFG_TASK_Q_EN > 0u
    (void)OS_MsgQFreeAll(&p_tcb->MsgQ);                     /* Free task's message queue messages                     */
#endif

    OSTaskDelHook(p_tcb);                                   /* Call user defined hook                                 */

#if OS_CFG_DBG_EN > 0u
    OS_TaskDbgListRemove(p_tcb);
#endif
    OSTaskQty--;                                            /* One less task being managed                            */

    OS_TaskInitTCB(p_tcb);                                  /* Initialize the TCB to default values                   */
    p_tcb->TaskState = (OS_STATE)OS_TASK_STATE_DEL;         /* Indicate that the task was deleted                     */

    OS_CRITICAL_EXIT_NO_SCHED();
    OSSched();                                              /* Find new highest priority task                         */

    *p_err = OS_ERR_NONE;
}
#endif

/*$PAGE*/
/*
************************************************************************************************************************
*                                                    FLUSH TASK's QUEUE
*
* Description: This function is used to flush the task's internal message queue.
*
* Arguments  : p_tcb       is a pointer to the task's OS_TCB.  Specifying a NULL pointer indicates that you wish to
*                          flush the message queue of the calling task.
*
*              p_err       is a pointer to a variable that will contain an error code returned by this function.
*
*                              OS_ERR_NONE           upon success
*                              OS_ERR_FLUSH_ISR      if you called this function from an ISR
*
* Returns     : The number of entries freed from the queue
*
* Note(s)     : 1) You should use this function with great care because, when to flush the queue, you LOOSE the
*                  references to what the queue entries are pointing to and thus, you could cause 'memory leaks'.  In
*                  other words, the data you are pointing to that's being referenced by the queue entries should, most
*                  likely, need to be de-allocated (i.e. freed).
************************************************************************************************************************
*/

#if OS_CFG_TASK_Q_EN > 0u
OS_MSG_QTY  OSTaskQFlush (OS_TCB  *p_tcb,
                          OS_ERR  *p_err)
{
    OS_MSG_QTY  entries;
    CPU_SR_ALLOC();



#ifdef OS_SAFETY_CRITICAL
    if (p_err == (OS_ERR *)0) {
        OS_SAFETY_CRITICAL_EXCEPTION();
        return ((OS_MSG_QTY)0);
    }
#endif

#if OS_CFG_CALLED_FROM_ISR_CHK_EN > 0u
    if (OSIntNestingCtr > (OS_NESTING_CTR)0) {              /* Can't flush a message queue from an ISR                */
       *p_err = OS_ERR_FLUSH_ISR;
        return ((OS_MSG_QTY)0);
    }
#endif

    if (p_tcb == (OS_TCB *)0) {                             /* Flush message queue of calling task?                   */
        CPU_CRITICAL_ENTER();
        p_tcb = OSTCBCurPtr;
        CPU_CRITICAL_EXIT();
    }

    OS_CRITICAL_ENTER();
    entries = OS_MsgQFreeAll(&p_tcb->MsgQ);                 /* Return all OS_MSGs to the OS_MSG pool                  */
    OS_CRITICAL_EXIT();
    *p_err  = OS_ERR_NONE;
    return (entries);
}
#endif

/*$PAGE*/
/*
************************************************************************************************************************
*                                                  WAIT FOR A MESSAGE
*
* Description: This function causes the current task to wait for a message to be posted to it.
*
* Arguments  : timeout       is an optional timeout period (in clock ticks).  If non-zero, your task will wait for a
*                            message to arrive up to the amount of time specified by this argument.
*                            If you specify 0, however, your task will wait forever or, until a message arrives.
*
*              opt           determines whether the user wants to block if the task's queue is empty or not:
*
*                                OS_OPT_PEND_BLOCKING
*                                OS_OPT_PEND_NON_BLOCKING
*
*              p_msg_size    is a pointer to a variable that will receive the size of the message
*
*              p_ts          is a pointer to a variable that will receive the timestamp of when the message was
*                            received.  If you pass a NULL pointer (i.e. (CPU_TS *)0) then you will not get the
*                            timestamp.  In other words, passing a NULL pointer is valid and indicates that you don't