Ztack学习笔记(2)-系统初始化分析

 main函数先执行初始化工作，包括硬件、网络层、任务等的初始化。

一 系统初始化

系统初始化函数主要完成内存分配、消息队列头、定时器、电源管理、任务系统及内存栈等的初始化，具体如下代码所示：

 //osal.c
 1 uint8 osal_init_system( void )
{
  // Initialize the Memory Allocation System
  osal_mem_init();/*初始化内存分配系统*/

  // Initialize the message queue
  osal_qHead = NULL;  /*初始化系统消息队列*/

  // Initialize the timers
  osalTimerInit(); /*初始化定时器*/

  // Initialize the Power Management System
  osal_pwrmgr_init(); /*初始化电源管理系统*/

  // Initialize the system tasks.
  osalInitTasks();/*初始化系统任务*/

  // Setup efficient search for the first free block of heap.
  osal_mem_kick();

  return ( SUCCESS );
}

 二 任务初始化

任务初始化，就是为系统的各个任务分配存储空间,初始化后，内存空间为全0(NULL),然后为各任务分配任务标识号taskID。即，这里重点是各任务的初始化，MAC层和NWK层的未开源看不到。

 //OSAL_SampleApp.c
 1 void osalInitTasks( void )
{
  uint8 taskID = 0;

  tasksEvents = (uint16 *)osal_mem_alloc( sizeof( uint16 ) * tasksCnt);//为当前OSAL中的各任务分配存储空间(实际上是一个任务数组),函数返回指向任务缓冲区的指针，因此tasksEvents指向该任务数组的首地址。
  osal_memset( tasksEvents, 0, (sizeof( uint16 ) * tasksCnt));
//把开辟的内存全部设置为0；sizeof( uint16 )是4个字节，即一个任务的长度（同样是uint16定义），乘以任务数量tasksCnt，即全部内存空间
  macTaskInit( taskID++ );//初始化各层任务 mac_taskID=0;
  nwk_init( taskID++ );
  Hal_Init( taskID++ );
#if defined( MT_TASK )
  MT_TaskInit( taskID++ );
#endif
  APS_Init( taskID++ );
#if defined ( ZIGBEE_FRAGMENTATION )
  APSF_Init( taskID++ );
#endif
  ZDApp_Init( taskID++ );
#if defined ( ZIGBEE_FREQ_AGILITY ) || defined ( ZIGBEE_PANID_CONFLICT )
  ZDNwkMgr_Init( taskID++ );
#endif
  SampleApp_Init( taskID );//SampleApp_taskID=6;用户创建的任务
}

       系统主循环函数里tasksEvents[ idx]和tasksArr[ idx]的idx与这里taskID是一一对应关系。数组tasksEvents[]里面元素是各任务事件，不是指向任务事件的指针，数组tasksArr[ ]是这个指针数组，里面元素是指向各任务事件处理函数的指针，这两个指针数组里面各元素的顺序要一一对应,因为后面需要相应任务调用相应事件处理函数。如下代码所示，其中的xx_loop与上面的yy_init是一一对应的关系。

//OSAL_Tasks.h
typedef unsigned short (*pTaskEventHandlerFn)( unsigned char task_id, unsigned short event );
//OSAL_SampleApp.c
const pTaskEventHandlerFn tasksArr[] = {
  macEventLoop,
  nwk_event_loop,
  Hal_ProcessEvent,
#if defined( MT_TASK )
  MT_ProcessEvent,
#endif
  APS_event_loop,
#if defined ( ZIGBEE_FRAGMENTATION )
  APSF_ProcessEvent,
#endif
  ZDApp_event_loop,
#if defined ( ZIGBEE_FREQ_AGILITY ) || defined ( ZIGBEE_PANID_CONFLICT )
  ZDNwkMgr_event_loop,
#endif
  SampleApp_ProcessEvent
};

const uint8 tasksCnt = sizeof( tasksArr ) / sizeof( tasksArr[0] );

三 应用初始化

void SampleApp_Init( uint8 task_id )
{
  SampleApp_TaskID = task_id;//osal分配的任务ID，这里为6，随着用户添加任务的增多而改变
  SampleApp_NwkState = DEV_INIT;//设备状态设定为ZDO层中定义的初始化状态（无连接）
  SampleApp_TransID = 0;//消息发送ID（多消息时有顺序之分）

  // Device hardware initialization can be added here or in main() (Zmain.c).
  // If the hardware is application specific - add it here.
  // If the hardware is other parts of the device add it in main().
//以下是通过跳线判断是路由器还是协调器
 #if defined ( BUILD_ALL_DEVICES )
  // The "Demo" target is setup to have BUILD_ALL_DEVICES and HOLD_AUTO_START
  // We are looking at a jumper (defined in SampleAppHw.c) to be jumpered
  // together - if they are - we will start up a coordinator. Otherwise,
  // the device will start as a router.
  if ( readCoordinatorJumper() )
    zgDeviceLogicalType = ZG_DEVICETYPE_COORDINATOR;
  else
    zgDeviceLogicalType = ZG_DEVICETYPE_ROUTER;
#endif // BUILD_ALL_DEVICES
//以下是决断是通过外部按键触发还是系统启动过程中触发启动芯片
#if defined ( HOLD_AUTO_START )
  // HOLD_AUTO_START is a compile option that will surpress ZDApp
  //  from starting the device and wait for the application to
  //  start the device.
  ZDOInitDevice(0);
#endif
//以下代码设置网络的通讯方式
  // Setup for the periodic message's destination address
  // Broadcast to everyone
  SampleApp_Periodic_DstAddr.addrMode = (afAddrMode_t)AddrBroadcast;
  SampleApp_Periodic_DstAddr.endPoint = SAMPLEAPP_ENDPOINT;
  SampleApp_Periodic_DstAddr.addr.shortAddr = 0xFFFF;

  // Setup for the flash command's destination address - Group 1
  SampleApp_Flash_DstAddr.addrMode = (afAddrMode_t)afAddrGroup;
  SampleApp_Flash_DstAddr.endPoint = SAMPLEAPP_ENDPOINT;
  SampleApp_Flash_DstAddr.addr.shortAddr = SAMPLEAPP_FLASH_GROUP;

  // Fill out the endpoint description.
  SampleApp_epDesc.endPoint = SAMPLEAPP_ENDPOINT;
  SampleApp_epDesc.task_id = &SampleApp_TaskID;
  SampleApp_epDesc.simpleDesc
            = (SimpleDescriptionFormat_t *)&SampleApp_SimpleDesc;
  SampleApp_epDesc.latencyReq = noLatencyReqs;

  // Register the endpoint description with the AF
  afRegister( &SampleApp_epDesc );

  // Register for all key events - This app will handle all key events
  RegisterForKeys( SampleApp_TaskID );

  // By default, all devices start out in Group 1
  SampleApp_Group.ID = 0x0001;
  osal_memcpy( SampleApp_Group.name, "Group 1", 7  );
  aps_AddGroup( SAMPLEAPP_ENDPOINT, &SampleApp_Group );

#if defined ( LCD_SUPPORTED )
  HalLcdWriteString( "SampleApp", HAL_LCD_LINE_1 );
#endif
}

以上为OSAL初始化大体流程，OSAL以及各软硬部件初始化完成后,就进入了系统主循环函数osal_start_system()，下节将介绍此。

 四 参考链接

【1】zstack sampleApp程序分析2