mac_scheduler.c

ucos在NEC平台下的移植

/*******************************************************************************************************
 *                                                                                                     *
 *        **********                                                                                   *
 *       ************                                                                                  *
 *      ***        ***                                                                                 *
 *      ***   +++   ***                                                                                *
 *      ***   + +   ***                                                                                *
 *      ***   +                         CHIPCON CC2420 INTEGRATED 802.15.4 MAC AND PHY                 *
 *      ***   + +   ***                                 Task Scheduler                                 *
 *      ***   +++   ***                                                                                *
 *      ***        ***                                                                                 *
 *       ************                                                                                  *
 *        **********                                                                                   *
 *                                                                                                     *
 *******************************************************************************************************
 * CONFIDENTIAL                                                                                        *
 * The use of this file is restricted by the signed MAC software license agreement.                    *
 *                                                                                                     *
 * Copyright Chipcon AS, 2004                                                                          *
 *******************************************************************************************************
 * This module contains the task scheduler used by the MAC layer. A task can begin at every backoff    *
 * slot boundary, assuming that no tasks of same or higher priorities running:                         *
 *                                                                                                     *
 *                        Task queues:     Task pool:                                                  *
 *                     |  H+<T             |   TT   |                                                  *
 * Execution priority: |  H <TTT    <----- |TT TTT T|                                                  *
 *                     |  M <TT            |T TT TTT|                                                  *
 *                     V  L <TTTTT         |--------|                                                  *
 *                           ^                                                                         *
 *                           |                                                                         *
 *                           One-way linked list, FIFO                                                 *
 *******************************************************************************************************
 * Compiler: AVR-GCC                                                                                   *
 * Target platform: CC2420DB, CC2420 + any ATMEGA MCU                                                  *
 *******************************************************************************************************
 * The revision history is located at the bottom of this file                                          *
 *******************************************************************************************************/
#pragma SFR
#pragma NOP
#pragma STOP
#pragma HALT
#pragma DI
#pragma EI
#pragma  section @@DATA sch at 0xE900///
#include "mac_headers.h"


//-------------------------------------------------------------------------------------------------------
// Scheduler data
MAC_TASK_INFO pMacTasks[MAC_TASK_COUNT];
MAC_TASK_QUEUE pMacTaskQueues[MAC_TASK_PRIORITY_COUNT];
//-------------------------------------------------------------------------------------------------------




//-------------------------------------------------------------------------------------------------------
//  void mschInit(void)
//
//  DESCRIPTION:
//      Initializes the task pool and the task queues.
//-------------------------------------------------------------------------------------------------------
void mschInit(void) {
    UINT8 n = 0; ///
    // Initialize the task pool
    for (n = 0; n < MAC_TASK_COUNT; n++) {///
        pMacTasks[n].occupied = FALSE;
        pMacTasks[n].taskNumber = n;
    }

    // Initialize the task queues
    for (n = 0; n < MAC_TASK_PRIORITY_COUNT; n++) {///
        pMacTaskQueues[n].firstTask = NO_TASK;
        pMacTaskQueues[n].lastTask = NO_TASK;
        pMacTaskQueues[n].taskInProgress = FALSE;
    }

} // mschInit




//-------------------------------------------------------------------------------------------------------
//  UINT8 mschReserveTask(void)
//
//  DESCRIPTION:
//      Reserves a task from the task pool (a task must be reserved before it can be used.
//
//  RETURN VALUE:
//      UINT8
//          The index of the reserved task (to be used with mschAddTask(...))
//-------------------------------------------------------------------------------------------------------
UINT8 mschReserveTask(void) {
UINT8 n = 0; ///
    // Find an unused task table entry and reserve it
    for (n = 0; n < MAC_TASK_COUNT; n++) {///
        DISABLE_GLOBAL_INT();
        if (!pMacTasks[n].occupied) {
            pMacTasks[n].occupied = TRUE;
            ENABLE_GLOBAL_INT();
            return n;
        }
        ENABLE_GLOBAL_INT();
    }
    return NO_TASK;

} // mschReserveTask




//-------------------------------------------------------------------------------------------------------
//  void mschReleaseTask(UINT8 taskNumber)
//
//  DESCRIPTION:
//      Clears the reservation for an unused task.
//
//  ARGUMENTS:
//      UINT8 taskNumber
//          The number of the task (returned by mschReserveTask())
//-------------------------------------------------------------------------------------------------------
void mschReleaseTask(UINT8 taskNumber) {
    if (taskNumber != NO_TASK) pMacTasks[taskNumber].occupied = FALSE;
} // mschReleaseTask




//-------------------------------------------------------------------------------------------------------
//  BOOL mschAddTask(UINT8 taskNumber, UINT8 priority, TFPTR pTaskFunc, WORD taskData)
//
//  DESCRIPTION:
//      Configures and adds a reserved to task to the desired task queue.
//
//  ARGUMENTS:
//      UINT8 taskNumber
//          The number of the task (returned by mschReserveTask(...))
//      UINT8 priority
//          MAC_TASK_PRI_HIGHEST, MAC_TASK_PRI_HIGH, MAC_TASK_PRI_MEDIUM or MAC_TASK_PRI_LOW
//      TFPTR pTaskFunc
//          A pointer to the task function (void TaskFunction(MAC_TASK_INFO *pTask))
//      WORD taskData
//          Two bytes of task data (usually a pointer to more data)
//
//  RETURN VALUE:
//      BOOL
//          The task was added (the task number was OK)
//-------------------------------------------------------------------------------------------------------
BOOL mschAddTask(UINT8 taskNumber, UINT8 priority, TFPTR pTaskFunc, WORD taskData) {
    MAC_TASK_INFO *pTask;
    MAC_TASK_QUEUE *pQueue;

    // The task index must be valid
    if (taskNumber == NO_TASK) return FALSE;
    
    DISABLE_GLOBAL_INT();

    // Initialize the task
    pTask = &pMacTasks[taskNumber];
    pTask->pTaskFunc = pTaskFunc;
    pTask->taskData = taskData;
    pTask->state = 0;
    pTask->priority = priority;
    pTask->nextTask = NO_TASK;

    // Update the queue pointers at the insertion point (last task in the queue)
    pQueue = &pMacTaskQueues[priority];
    if (pQueue->firstTask == NO_TASK) {
        pQueue->firstTask = taskNumber;
        pQueue->lastTask = taskNumber;
    } else {
        pMacTasks[pQueue->lastTask].nextTask = taskNumber;
        pQueue->lastTask = taskNumber;
    }
    ENABLE_GLOBAL_INT();
    return TRUE;

} // mschAddTask




//-------------------------------------------------------------------------------------------------------
//  void mschRemoveTask(UINT8 priority, BYTE flags)
//
//  DESCRIPTION:
//      Removes the active task from the specified task queue. This function is usually run from the task
//      function when it's about to finished, or before it makes a call to the higher layer.
//
//  ARGUMENTS:
//      UINT8 priority
//          The priority of the task to be removed
//      BYTE flags
//          MSCH_KEEP_TASK_RESERVED_BM: The task is not released back to the task pool
//          MSCH_KEEP_TASK_IN_PROGRESS_BM: Does not allow other tasks of the same priority to run before
//              the current task has finished (even if it is removed from the queue).
//-------------------------------------------------------------------------------------------------------
void mschRemoveTask(UINT8 priority, BYTE flags) {
    UINT8 taskNumber;
    MAC_TASK_INFO *pTask;
    MAC_TASK_QUEUE *pQueue = &pMacTaskQueues[priority];
    
    DISABLE_GLOBAL_INT();
    
    // Get the task table index number, and make sure that it is valid
    taskNumber = pQueue->firstTask;
      
    // Flag-dependent operations
    pTask = &pMacTasks[taskNumber];
    if (!(flags & MSCH_KEEP_TASK_RESERVED_BM)) pTask->occupied = FALSE;
    if (!(flags & MSCH_KEEP_TASK_IN_PROGRESS_BM)) pQueue->taskInProgress = FALSE;

    // Move the "first task" pointer one step forward
    pQueue->firstTask = pTask->nextTask;
    if (pQueue->firstTask == NO_TASK) {
        pQueue->lastTask = NO_TASK;
    } else if (pQueue->lastTask == taskNumber) {
        pQueue->lastTask = NO_TASK;
    }
    
    ENABLE_GLOBAL_INT();
} // mschRemoveTask




//-------------------------------------------------------------------------------------------------------
//  void mschRescheduleTask(MAC_TASK_INFO *pTask, UINT8 state) 
//
//  DESCRIPTION:
//      Removes the currently running task from a queue, and adds it to the back of the same queue, 
//      possibly behind a number of waiting tasks which now will be run first.
//
//  ARGUMENTS:
//      MAC_TASK_INFO *pTask
//          The task to be rescheduled
//      UINT8 state
//          The task state when run after the rescheduling.
//-------------------------------------------------------------------------------------------------------
void mschRescheduleTask(MAC_TASK_INFO *pTask, UINT8 state) {
    mschRemoveTask(pTask->priority, MSCH_KEEP_TASK_RESERVED_BM | MSCH_KEEP_TASK_IN_PROGRESS_BM);
    mschAddTask(pTask->taskNumber, pTask->priority, pTask->pTaskFunc, pTask->taskData);
    pTask->state = state;
} // mschRescheduleTask




//-------------------------------------------------------------------------------------------------------
//  void mschDoTask(void)
//
//  DESCRIPTION:
//      Used by the timer module to start or resume a task at every backoff slot boundary
//
//  ARGUMENTS:
//      None      
//
//  RETURN VALUE:
//      None
//-------------------------------------------------------------------------------------------------------
void mschDoTask(void) {
    UINT8 taskNumber;
    MAC_TASK_QUEUE *pQueue;
    MAC_TASK_INFO *pTask;
    
    // Execute tasks by priority
    UINT8 n = MAC_TASK_PRIORITY_COUNT - 1;
    do {
        
        // Stop if there's a task in progress
        pQueue = &pMacTaskQueues[n];

		
    if (pQueue->taskInProgress) return;
		///if (pQueue->taskInProgress) continue;
		
        
        // If there's a valid task in the queue, then start it
        DISABLE_GLOBAL_INT();
        taskNumber = pQueue->firstTask;
        if (taskNumber != NO_TASK) {
            pQueue->taskInProgress = TRUE;
            pTask = &pMacTasks[taskNumber];
ENABLE_GLOBAL_INT();
            ((TFPTR) pTask->pTaskFunc)(pTask);
            pQueue->taskInProgress = FALSE;
///ENABLE_GLOBAL_INT();///
            return;
        }
        ENABLE_GLOBAL_INT();
    } while (n--);

} // mschDoTask




/*******************************************************************************************************
 * Revision history:
 *
 * $Log: mac_scheduler.c,v $
 * Revision 1.8  2004/12/07 09:47:50  thl
 * Fixed potential coruption of memmory when max payload is recived.
 *
 * Revision 1.7  2004/11/10 09:33:15  thl
 * Fixed a number of bugs according to: MAC software check lists.xls
 *
 * Revision 1.6  2004/08/13 13:04:47  jol
 * CC2420 MAC Release v0.7
 *
 *
 *******************************************************************************************************/