winCE中实现虚拟串口的方法

转载请标明是引用于 http://blog.csdn.net/chenyujing1234 

欢迎大家拍砖!

 

环境：wince6.0+ARM+Freescell

 

一、目的

设计一个读GPS串口数据的驱动，并注册为COM口。

二、实现过程

1、COM_Init

注册表中读出GPS COM口号及是否Debug，创建共享数据区，创建读取数据的线程，打开GPS真实的COM口；

开一线程MonitorCommEventProc读取GPS口数据，并用DecodeGpsBuf解析读取到的数据。

这里注意在WinCE驱动中的XXX_Init中的入口参数DWORD dwContext通过

LPCTSTR regKeyPath = (LPCTSTR)dwContext;HKEY hKey = OpenDeviceKey(regKeyPath);可以转化为其所在驱动的.reg注册的HKEY。

 

DWORD COM_Init(DWORD dwContext)   
{   
	DWORD dwPare,dwReturn;
	LPCTSTR regKeyPath = (LPCTSTR)dwContext;
	HKEY hKey = OpenDeviceKey(regKeyPath);

	DWORD size = 4;
	DWORD index;

	MyPDebugStringW(L"Enter Com_Init");
	if ( hKey == NULL )
	{
		MyPDebugStringW(L"Fun:%s; hKey == NULL", __FUNCTIONW__);
		//return NULL;
	}
	if (ERROR_SUCCESS != RegQueryValueEx(hKey,_T("GpsCom"), 0, NULL, (LPBYTE)&g_GsmPort, &size))
	{
	//	RETAILMSG(TRUE,(TEXT("We get original com index :%d ......\r\n"),g_GsmPort));
	}
	if (ERROR_SUCCESS != RegQueryValueEx(hKey,_T("Dbg"), 0, NULL, (LPBYTE)&g_bDbg, &size))
	{
	//	RETAILMSG(TRUE,(TEXT("We get original com index :%d ......\r\n"),g_GsmPort));
	}
#if 0
	if (ERROR_SUCCESS != RegQueryValueEx(hKey,_T("Index"), 0, NULL, (LPBYTE)&index, &size))
	{
		RegCloseKey(hKey);
		return NULL;
	}

	GetFromVirtalRegistry((BYTE *)&g_GsmPort,&size, NULL, HKEY_LOCAL_MACHINE, _T("virtalSerial"), _T("Index"));
#endif
	RegCloseKey(hKey);

	MyPDebugStringW(L"The apply port is com%d", g_GsmPort);
	InitializeCriticalSection(&g_csOpen);   
	InitializeCriticalSection(&g_csRead);   
	InitializeCriticalSection(&g_csWrite);   

	g_dwWM_PEKSUNNY  = RegisterWindowMessage(L"WM_PEKSUNNY");
	if(!g_hEventComm)
		g_hEventComm = CreateEvent(NULL,TRUE,FALSE,NULL);   

#if 0
	//给GSM模块上电
	dwPare=(0<<16)|(21<<8)|(1);
	KernelIoControl(IOCTL_HAL_SET_GPIO_HIGH_LOW,&dwPare,sizeof(DWORD),NULL,0,&dwReturn);
	dwPare=(0<<16)|(26<<8)|(1);
	KernelIoControl(IOCTL_HAL_SET_GPIO_HIGH_LOW,&dwPare,sizeof(DWORD),NULL,0,&dwReturn);
#endif
	g_pGpsDataMem = (PGPSDATA)ReadShareArea();

	g_pGpsDataMem->iSatNum = 67;

	return OpenTransmitThr();

}   

BOOL OpenTransmitThr(){	TCHAR szPort[12];	swprintf(szPort, L"COM%u:", g_GsmPort);	g_hCom = CreateFile(szPort, GENERIC_READ | GENERIC_WRITE , 0, NULL, OPEN_EXISTING, 0, NULL);	if(g_hCom == INVALID_HANDLE_VALUE )   	{   		MyPDebugStringW(L"Fun:%s; CreateFile %s failed", __FUNCTIONW__, szPort);  		return FALSE;   	}   	else  	{   		MyPDebugStringW(L"Fun:%s; CreateFile %s success", __FUNCTIONW__, szPort);   	} #if 1	if(!InitComDcb(g_hCom,CBR_9600))	{		MyPDebugStringW(L"Fun:%s; Line:%d; InitComDcb failed", __FUNCTIONW__, __LINE__);	}		//goto SET_SUCCEED_FLAG;	if(!InitComTimeOuts(g_hCom))	{		MyPDebugStringW(L"Fun:%s; Line:%d; InitComTimeOuts failed", __FUNCTIONW__, __LINE__);	}		//goto SET_SUCCEED_FLAG;	SetupComm(g_hCom, 1024,1024);	PurgeComm(g_hCom, PURGE_TXCLEAR|PURGE_RXCLEAR|PURGE_RXABORT|PURGE_TXABORT);	//设置端口上指定信号的状态	// SETDTR: 发送DTR (data terminal ready)信号	// SETRTS: 发送RTS (request to send)信号	EscapeCommFunction(g_hCom,SETDTR);	EscapeCommFunction(g_hCom,SETRTS);#endif	InterlockedExchange((LPLONG)(&g_bExitMonitorProc),FALSE);   	g_hReadThread =CreateThread(NULL,NULL,MonitorCommEventProc,NULL,NULL,NULL); 	return TRUE;}

 

DWORD MonitorCommEventProc(LPVOID pParam)   
{   
	TCHAR wcDebug[1024] = {0};

	MyPDebugStringW(L"Enter MonitorCommEventProc");
	SetCommMask(g_hCom, EV_RXCHAR);
	while(!g_bExitMonitorProc)   
	{    
		DWORD   dwErrorFlags;
		COMSTAT ComStat;
		DWORD dwLength;
		DWORD dwEvtMask = 0;   
		DWORD dwRead = 0;

		BOOL bWaitRes = WaitCommEvent(g_hCom, &dwEvtMask, NULL); 
		//		RETAILMSG(TRUE,(TEXT("VSP comm event come %d ,last set is %d\r\n"),dwEvtMask,g_dwWaitMask));
		//MyPDebugStringW(L"Gps com has event come up");
		if(dwEvtMask==0)
		{
			//wait error
			Sleep(30);

			if(g_dwWaitMask)
			{
				continue; //Last set is not null,give up,because exit read thread need null event
			}
		}

		if(bWaitRes == FALSE)   
		{   
			continue;   
		}     

		if(dwEvtMask & EV_RXCHAR)   
		{   
			Sleep(20);

			EnterCriticalSection(&g_csRead);    

			ClearCommError(g_hCom,&dwErrorFlags,&ComStat);
			dwLength=ComStat.cbInQue;

			if(/*dwLength>0*/1)
			{
				ZeroMemory(g_vtBufRead, sizeof(g_vtBufRead));
				ReadFile(g_hCom, &g_vtBufRead, sizeof(g_vtBufRead), &dwRead, NULL);

			 	mbstowcs(wcDebug,  (char*)g_vtBufRead, strlen((char*)g_vtBufRead));
			//	OutputErrorInfo(L"Read data:%s\r\n", wcDebug);
			//	DecodeGpsNema((char*)g_vtBufRead);
				DecodeGpsBuf((char*)g_vtBufRead);

				g_dwLenReadBuf=dwRead;

				if(g_pChanle1)
				{
					g_pChanle1->iIndex = 0;
					g_pChanle1->iTolLen = dwRead;
					memcpy(g_pChanle1->cReadBuf,g_vtBufRead,dwRead);
				}
				if(g_pChanle2)
				{
					g_pChanle2->iIndex = 0;
					g_pChanle2->iTolLen = dwRead;
					memcpy(g_pChanle2->cReadBuf,g_vtBufRead,dwRead);
				}
				if(g_pChanle3)
				{
					g_pChanle3->iIndex = 0;
					g_pChanle3->iTolLen = dwRead;
					memcpy(g_pChanle3->cReadBuf,g_vtBufRead,dwRead);
				}

			}
			else
			{
				RETAILMSG(g_bDbg,(L"[VSP]:ClearCommError(%d): dwLength is 0,continue ......\r\n",dwErrorFlags));
				//	LeaveCriticalSection(&g_csRead);
				//	continue;
			}

			LeaveCriticalSection(&g_csRead);   
		}   
#if 0
		//if(dwEvtMask == EV_RXCHAR && ((g_dwWaitMask & EV_RXCHAR) == 0 || dwRead == 0))   
		if(dwEvtMask == EV_RXCHAR && ((g_dwWaitMask & EV_RXCHAR) == 0 ))   
		{   
			//The return event mask is only EV_RXCHAR and there is not EV_RXCHAR in the wait mask.   
			RETAILMSG(g_bDbg,(L"Skip send event C......\r\n"));
			continue;   
		}   
#endif
		InterlockedExchange((LPLONG)(&g_dwEvtMask),dwEvtMask);   
		PulseEvent(g_hEventComm);
		//	RETAILMSG(TRUE,(TEXT("PulseEvent %d\r\n"),g_dwEvtMask));

		//Sleep for other thread to respond to the event   
		//	Sleep(100);   
		Sleep(20); 

		DEBUGMSG(g_bDbg,(TEXT("[VSP]:PulseEvent! The event-mask is 0x%x\r\n"),dwEvtMask));    

	}   

	MyPDebugStringW(L"Fun:%s; over MonitorCommEventProc", __FUNCTIONW__);

	return 0;   
}   

2、COM_Open

为了让上层的应用程序能实现三次打开此设备而初始化三块COM_DEV内存。

typedef struct
{
	int iIndex;
	int iTolLen;
	BYTE cReadBuf[READ_BUFFER_LENGTH];
}COM_DEV,*PCOM_DEV;

 

DWORD COM_Open(DWORD dwData, DWORD dwAccess, DWORD dwShareMode)   
{   
	PCOM_DEV pComDev = NULL;

	MyPDebugStringW(L"Enter %s", __FUNCTIONW__);
	EnterCriticalSection(&g_csOpen);   
	if(!g_pChanle1)
	{
		g_pChanle1 = new COM_DEV;
		g_pChanle1->iTolLen = g_pChanle1->iIndex = 0;
		pComDev = g_pChanle1;
	}
	else if(!g_pChanle2)
	{
		g_pChanle2 = new COM_DEV;
		g_pChanle2->iTolLen=g_pChanle2->iIndex =0;
		pComDev = g_pChanle2;
	}
	else if(!g_pChanle3)
	{
		g_pChanle3 = new COM_DEV;
		g_pChanle3->iTolLen=g_pChanle3->iIndex =0;
		pComDev = g_pChanle3;
	}
	else
	{
		return 0;
	}

#if 1
	//The variable   
	if(g_uiOpenCount >= MAX_OPEN_CNT)
		return 0;

	g_uiOpenCount ++;  
	pComDev->iIndex = 0;
	//	dwResult = dwData;   

LEAVE_CRITICAL_SECTION:    
#endif
	LeaveCriticalSection(&g_csOpen); 
	return (DWORD)pComDev;   
}   

3、COM_Deinit

主要是关闭读线程，反初始化资源；

关闭线程的方法有几种：

（1）是直接CloseHandle真实的COM口，然后在线程中会WaitCommEvent失败，然后退出，这这种方法太间接；

（2）设备全局变量，采用原子操作函数来变化它的标识。

A、定义变量：BOOL g_bExitMonitorProc = FALSE;   ；

B、在线程中：

DWORD MonitorCommEventProc(LPVOID pParam)   
{   
 TCHAR wcDebug[1024] = {0};

 MyPDebugStringW(L"Enter MonitorCommEventProc");
 SetCommMask(g_hCom, EV_RXCHAR);
 while(!g_bExitMonitorProc)   
 {  

C、在创建线程前使它为FLASE：

InterlockedExchange((LPLONG)(&g_bExitMonitorProc),FALSE);   

D、在要关闭线程时：

BOOL CloseTransmitThr()
{
	DWORD dwMask = 0; 
	//Notify the monitor thread to exit.    
	InterlockedExchange((LPLONG)(&g_bExitMonitorProc),TRUE);   

4、COM_IOControl

为了使应用程序能像使用真实COM口一样的使用虚拟COM口，我们需要给出COM_IOControl，并去case需要的IOCODE，

（1）IOCTL_SERIAL_SET_TIMEOUTS
应用程序设备虚拟COM口的此接口，我们就给真实的COM口通过系统API SetCommTimeouts来设置：

SetCommTimeouts(g_hCom,(LPCOMMTIMEOUTS)(pBufIn));   

（2）IOCTL_SERIAL_GET_TIMEOUTS

类似于（1）

（3）IOCTL_SERIAL_SET_DCB

类似于（1）

（4）IOCTL_SERIAL_GET_DCB

类似于（1）

（5）IOCTL_SERIAL_WAIT_ON_MASK

（5、1）因为我们的读线程中有调用了WaitCommEvent，所以这里我们得做好同步，同步的方法是：

A、初始化事件

g_hEventComm = CreateEvent(NULL,TRUE,FALSE,NULL);   

B、在读取完数据后让事件激活

PulseEvent(g_hEventComm);

C、在case IOCTL_SEARIAL_WAIT_ON_MASK时去等待

case IOCTL_SERIAL_WAIT_ON_MASK:   
		{      
			MyPDebugStringW(L"receive IOCTL_SERIAL_WAIT_ON_MASK");
			if(dwBufOutSize < sizeof(DWORD) ||  WaitForSingleObject(g_hEventComm,INFINITE) == WAIT_TIMEOUT)   
			{   

（5、2）把读线程WaitCommEvent返回的结果返回给应用程序

A、

BOOL bWaitRes = WaitCommEvent(g_hCom, &dwEvtMask, NULL); 

B、

InterlockedExchange((LPLONG)(&g_dwEvtMask),dwEvtMask);   

C、在case IOCTL_SEARIAL_WAIT_ON_MASK等待成功时

InterlockedExchange((LPLONG)(pBufOut),g_dwEvtMask);   

 

（6）IOCTL_SERIAL_SET_WAIT_MASK

g_dwWaitMask = *(DWORD*)(pBufIn);   
			RETAILMSG(g_bDbg,(TEXT("VSP : Set wait mask : %d ......\r\n"),g_dwWaitMask));
			return SetCommMask(g_hCom,g_dwWaitMask | EV_RXCHAR); //The driver need the EV_RXCHAR notify event.   

也是调用了系统的SetCommMask，不过对入口设置的标志或上了EV_RXHCAR，因为我们的驱动需要EX_RXCHAR 通知事件。

 

（7）IOCTL_SERIAL_GET_WAIT_MASK

（8）IOCTL_SERIAL_GET_COMMSTATUS

（9）

 

 

三、实现机制要点

（1）采用文件映射实现共享数据。

（1、1）共享的数据为GPS数据，在COM_Init中去创建文件映射：

	g_pGpsDataMem = (PGPSDATA)ReadShareArea();

	g_pGpsDataMem->iSatNum = 67;

映射文件的大小由SHARE_MEM_SIZE指定，为256。

PVOID ReadShareArea()   
{   
	PBYTE pShareMem=NULL;
	HANDLE hMySharedFile=
		CreateFileMapping((HANDLE)0xFFFFFFFF,NULL,PAGE_READWRITE,0,SHARE_MEM_SIZE,SHARE_MEM_NAME);
	if(hMySharedFile!=NULL)
		pShareMem =(PBYTE)MapViewOfFile(hMySharedFile,FILE_MAP_ALL_ACCESS,0,0,0);
	CloseHandle(hMySharedFile);

	return pShareMem;  
}

（1、2）在COM _Open中为应用程序分析三个内存用于存储在读线程中得到的数据。

其中存储线程中得到的数据为：

DecodeGpsBuf((char*)g_vtBufRead);

				g_dwLenReadBuf=dwRead;

				if(g_pChanle1)
				{
					g_pChanle1->iIndex = 0;
					g_pChanle1->iTolLen = dwRead;
					memcpy(g_pChanle1->cReadBuf,g_vtBufRead,dwRead);
				}
				if(g_pChanle2)
				{
					g_pChanle2->iIndex = 0;
					g_pChanle2->iTolLen = dwRead;
					memcpy(g_pChanle2->cReadBuf,g_vtBufRead,dwRead);
				}
				if(g_pChanle3)
				{
					g_pChanle3->iIndex = 0;
					g_pChanle3->iTolLen = dwRead;
					memcpy(g_pChanle3->cReadBuf,g_vtBufRead,dwRead);
				}

（1、3）在导出给应用程序的接口ReadGpsFromCom中把映射的数据拷到形参中

BOOL ReadGpsFromCom(PVOID pReadBuf)
{
	MyPDebugStringW(L"Enter %s", __FUNCTIONW__);
	PGPSDATA pGpsDataMem= (PGPSDATA)ReadShareArea();;
	memcpy(pReadBuf,pGpsDataMem,sizeof(GPSDATA));
	if(pGpsDataMem)
		UnmapViewOfFile(pGpsDataMem);
	return TRUE;
}