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
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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 0if (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"));#endifRegCloseKey(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);#endifg_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 1if(!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);#endifInterlockedExchange((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 errorSleep(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; } #endifInterlockedExchange((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: #endifLeaveCriticalSection(&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); 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）
（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;}