如何编写Windows CE.net的usb驱动程序(2)
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上述讲了堆理论，可能读者脑袋都已经大了，为此，我们举个简单的例子来详细说明一下驱动程序的开发过程。
例如我们有个USBMouse设备，设备信息描述如下：
DeviceDescriptor:
bcdUSB:0x0100
bDeviceClass:0x00
bDeviceSubClass:0x00
bDeviceProtocol:0x00
bMaxPacketSize0:0x08(8)
idVendor:0x05E3(GenesysLogicInc.)
idProduct:0x0001
bcdDevice:0x0101
iManufacturer:0x00
iProduct:0x01
iSerialNumber:0x00
bNumConfigurations:0x01
ConnectionStatus:DeviceConnected
CurrentConfigValue:0x01
DeviceBusSpeed:Low
DeviceAddress:0x02
OpenPipes:1
EndpointDescriptor:
bEndpointAddress:0x81
TransferType:Interrupt
wMaxPacketSize:0x0003(3)
bInterval:0x0A
可以看出上述设备有一个中断PIPE，包的最大值为3。可能有人问上述的值怎么得到的，win2k的DDK中有个usbview的例程，编译一下，将你的USB设备插到PC机的USB口中，运行usbview.exe即可看得相应的设备信息。
有了这些基本信息，就可以编写USB设备了，首先声明一下，下面的代码取自微软的USB鼠标样本程序，版权归微软所有，此处仅仅借用来描述一下USB鼠标驱动的开发过程，读者如需要引用此代码，需要得到微软的同意。
首先，必须输出USBD要求调用的三个函数，首先到设备插入到USB端口时，USBD会调用USBDeviceAttach()函数，相应的代码如下：
extern"C"BOOL
USBDeviceAttach(
USB_HANDLEhDevice,//USB设备句柄
LPCUSB_FUNCSlpUsbFuncs,//USBDI的函数集合
LPCUSB_INTERFACElpInterface,//设备接口描述信息
LPCWSTRszUniqueDriverId,//设备ID描述字符串。
LPBOOLfAcceptControl,//返回TRUE，标识我们可以控制此设备，反之表示不能控制
DWORDdwUnused)
{
*fAcceptControl=FALSE;
//我们的鼠标设备有特定的描述信息，要检测是否是我们的设备。
if(lpInterface==NULL)
returnFALSE;
//打印相关的USB设备接口描述信息。
DEBUGMSG(ZONE_INIT,(TEXT("USBMouse:DeviceAttach,IF%u,#EP:%u,Class:%u,Sub:%u,Prot:%urn"),lpInterface->Descriptor.bInterfaceNumber,lpInterface->Descriptor.bNumEndpoints,lpInterface->Descriptor.bInterfaceClass,lpInterface->Descriptor.bInterfaceSubClass,lpInterface->Descriptor.bInterfaceProtocol));
//初试数据USB鼠标类，产生一个接受USB鼠标数据的线程
CMouse*pMouse=newCMouse(hDevice,lpUsbFuncs,lpInterface);
if(pMouse==NULL)
returnFALSE;
if(!pMouse->Initialize())
{
deletepMouse;
returnFALSE;
}
//注册一个监控USB设备事件的回调函数，用于监控USB设备是否已经拔掉。
(*lpUsbFuncs->lpRegisterNotificationRoutine)(hDevice,
USBDeviceNotifications,pMouse);
*fAcceptControl=TRUE;
returnTRUE;
}
第二个函数是USBInstallDriver（）函数，
一些基本定义如下：
constWCHARgcszRegisterClientDriverId[]=L"RegisterClientDriverID";
constWCHARgcszRegisterClientSettings[]=L"RegisterClientSettings";
constWCHARgcszUnRegisterClientDriverId[]=L"UnRegisterClientDriverID";
constWCHARgcszUnRegisterClientSettings[]=L"UnRegisterClientSettings";
constWCHARgcszMouseDriverId[]=L"Generic_Sample_Mouse_Driver";
函数接口如下：
extern"C"BOOL
USBInstallDriver(
LPCWSTRszDriverLibFile)//@parm[IN]-ContainsclientdriverDLLname
{
BOOLfRet=FALSE;
HINSTANCEhInst=LoadLibrary(L"USBD.DLL");
//注册USB设备信息
if(hInst)
{
LPREGISTER_CLIENT_DRIVER_IDpRegisterId=(LPREGISTER_CLIENT_DRIVER_ID)
GetProcAddress(hInst,gcszRegisterClientDriverId);
LPREGISTER_CLIENT_SETTINGSpRegisterSettings=
(LPREGISTER_CLIENT_SETTINGS)GetProcAddress(hInst,
gcszRegisterClientSettings);
if(pRegisterId&&pRegisterSettings)
{
USB_DRIVER_SETTINGSDriverSettings;
DriverSettings.dwCount=sizeof(DriverSettings);
//设置我们的特定的信息。
DriverSettings.dwVendorId=USB_NO_INFO;
DriverSettings.dwProductId=USB_NO_INFO;
DriverSettings.dwReleaseNumber=USB_NO_INFO;
DriverSettings.dwDeviceClass=USB_NO_INFO;
DriverSettings.dwDeviceSubClass=USB_NO_INFO;
DriverSettings.dwDeviceProtocol=USB_NO_INFO;
DriverSettings.dwInterfaceClass=0x03;//HID
DriverSettings.dwInterfaceSubClass=0x01;//bootdevice
DriverSettings.dwInterfaceProtocol=0x02;//mouse
fRet=(*pRegisterId)(gcszMouseDriverId);
if(fRet)
{
fRet=(*pRegisterSettings)(szDriverLibFile,
gcszMouseDriverId,NULL,&DriverSettings);
if(!fRet)
{
//BUGBUGunregistertheClientDriver’sID
}
}
}
else
{
RETAILMSG(1,(TEXT("!USBMouse:ErrorgettingUSBDfunctionpointersrn")));
}
FreeLibrary(hInst);
}
returnfRet;
}
上述代码主要用于产生USB设备驱动程序需要的注册表信息，需要注意的是：USB设备驱动程序不使用标准的注册表函数，而是使用RegisterClientDriverID（）和RegisterClientSettings来注册相应的设备信息。[!--empirenews.page--]
另外一个函数是USBUninstallDriver()函数，具体代码如下：
extern"C"BOOL
USBUnInstallDriver()
{
BOOLfRet=FALSE;
HINSTANCEhInst=LoadLibrary(L"USBD.DLL");
if(hInst)
{
LPUN_REGISTER_CLIENT_DRIVER_IDpUnRegisterId=
(LPUN_REGISTER_CLIENT_DRIVER_ID)
GetProcAddress(hInst,gcszUnRegisterClientDriverId);
LPUN_REGISTER_CLIENT_SETTINGSpUnRegisterSettings=
(LPUN_REGISTER_CLIENT_SETTINGS)GetProcAddress(hInst,
gcszUnRegisterClientSettings);
if(pUnRegisterSettings)
{
USB_DRIVER_SETTINGSDriverSettings;
DriverSettings.dwCount=sizeof(DriverSettings);
//必须填入与注册时相同的信息。
DriverSettings.dwVendorId=USB_NO_INFO;
DriverSettings.dwProductId=USB_NO_INFO;
DriverSettings.dwReleaseNumber=USB_NO_INFO;
DriverSettings.dwDeviceClass=USB_NO_INFO;
DriverSettings.dwDeviceSubClass=USB_NO_INFO;
DriverSettings.dwDeviceProtocol=USB_NO_INFO;
DriverSettings.dwInterfaceClass=0x03;//HID
DriverSettings.dwInterfaceSubClass=0x01;//bootdevice
DriverSettings.dwInterfaceProtocol=0x02;//mouse
fRet=(*pUnRegisterSettings)(gcszMouseDriverId,NULL,
&DriverSettings);
}
if(pUnRegisterId)
{
BOOLfRetTemp=(*pUnRegisterId)(gcszMouseDriverId);
fRet=fRet?fRetTemp:fRet;
}
FreeLibrary(hInst);
}
returnfRet;
}
此函数主要用于删除USBInstallDriver()时创建的注册表信息，同样的它使用自己的函数接口UnRegisterClientDriverID（）和UnRegisterClientSettings（）来做相应的处理。
另外一个需要处理的注册的监控通知函数USBDeviceNotifications（）：
extern"C"BOOLUSBDeviceNotifications(LPVOIDlpvNotifyParameter,DWORDdwCode,
LPDWORD*dwInfo1,LPDWORD*dwInfo2,LPDWORD*dwInfo3,
LPDWORD*dwInfo4)
{
CMouse*pMouse=(CMouse*)lpvNotifyParameter;
switch(dwCode)
{
caseUSB_CLOSE_DEVICE:
//删除相关的资源。
deletepMouse;
returnTRUE;
}
returnFALSE;
}
USB鼠标的类的定义如下：
classCMouse
{
public:
CMouse::CMouse(USB_HANDLEhDevice,LPCUSB_FUNCSlpUsbFuncs,
LPCUSB_INTERFACElpInterface);
~CMouse();
BOOLInitialize();
private:
//传输完毕调用的回调函数
staticDWORDCALLBACKMouseTransferCompleteStub(LPVOIDlpvNotifyParameter);
//中断处理函数
staticULONGCALLBACKCMouse::MouseThreadStub(PVOIDcontext);
DWORDMouseTransferComplete();
DWORDMouseThread();
BOOLSubmitInterrupt();
BOOLHandleInterrupt();
BOOLm_fClosing;
BOOLm_fReadyForMouseEvents;
HANDLEm_hEvent;
HANDLEm_hThread;
USB_HANDLEm_hDevice;
USB_PIPEm_hInterruptPipe;
USB_TRANSFERm_hInterruptTransfer;
LPCUSB_FUNCSm_lpUsbFuncs;
LPCUSB_INTERFACEm_pInterface;
BOOLm_fPrevButton1;
BOOLm_fPrevButton2;
BOOLm_fPrevButton3;
//数据接受缓冲区。
BYTEm_pbDataBuffer[8];
};
具体实现如下：
//构造函数，初始化时调用
CMouse::CMouse(USB_HANDLEhDevice,LPCUSB_FUNCSlpUsbFuncs,
LPCUSB_INTERFACElpInterface)
{
m_fClosing=FALSE;
m_fReadyForMouseEvents=FALSE;
m_hEvent=NULL;
m_hThread=NULL;
m_hDevice=hDevice;
m_hInterruptPipe=NULL;
m_hInterruptTransfer=NULL;
m_lpUsbFuncs=lpUsbFuncs;
m_pInterface=lpInterface;
m_fPrevButton1=FALSE;
m_fPrevButton2=FALSE;
m_fPrevButton3=FALSE;
memset(m_pbDataBuffer,0,sizeof(m_pbDataBuffer));
}
//析构函数，用于清除申请的资源。
CMouse::~CMouse()
{
//通知系统去关闭相关的函数接口。
m_fClosing=TRUE;
//Wakeuptheconnectionthreadagainandgiveittimetodie.
if(m_hEvent!=NULL)
{
//通知关闭数据接受线程。
SetEvent(m_hEvent);
if(m_hThread!=NULL)
{
DWORDdwWaitReturn;
dwWaitReturn=WaitForSingleObject(m_hThread,1000);
if(dwWaitReturn!=WAIT_OBJECT_0)
{
TerminateThread(m_hThread,DWORD(-1));
}
CloseHandle(m_hThread);
m_hThread=NULL;
}
CloseHandle(m_hEvent);
m_hEvent=NULL;
}
if(m_hInterruptTransfer)
(*m_lpUsbFuncs->lpCloseTransfer)(m_hInterruptTransfer);
if(m_hInterruptPipe)
(*m_lpUsbFuncs->lpClosePipe)(m_hInterruptPipe);
}
//初始化USB鼠标驱动程序
BOOLCMouse::Initialize()
{
LPCUSB_DEVICElpDeviceInfo=(*m_lpUsbFuncs->lpGetDeviceInfo)(m_hDevice);
//检测配置：USB鼠标应该只有一个中断管道
if((m_pInterface->lpEndpoints[0].Descriptor.bmAttributes&USB_ENDPOINT_TYPE_MASK)!=USB_ENDPOINT_TYPE_INTERRUPT)
{
RETAILMSG(1,(TEXT("!USBMouse:EP0wrongtype(%u)!rn"),[!--empirenews.page--]
m_pInterface->lpEndpoints[0].Descriptor.bmAttributes));
returnFALSE;
}
DEBUGMSG(ZONE_INIT,(TEXT("USBMouse:EP0:MaxPacket:%u,Interval:%urn"),
m_pInterface->lpEndpoints[0].Descriptor.wMaxPacketSize,
m_pInterface->lpEndpoints[0].Descriptor.bInterval));
m_hInterruptPipe=(*m_lpUsbFuncs->lpOpenPipe)(m_hDevice,
&m_pInterface->lpEndpoints[0].Descriptor);
if(m_hInterruptPipe==NULL){
RETAILMSG(1,(TEXT("Mouse:Erroropeninginterruptpipern")));
return(FALSE);
}
m_hEvent=CreateEvent(NULL,FALSE,FALSE,NULL);
if(m_hEvent==NULL)
{
RETAILMSG(1,(TEXT("USBMouse:ErroronCreateEventforconnecteventrn")));
return(FALSE);
}
//创建数据接受线程
m_hThread=CreateThread(0,0,MouseThreadStub,this,0,NULL);
if(m_hThread==NULL)
{
RETAILMSG(1,(TEXT("USBMouse:ErroronCreateThreadrn")));
return(FALSE);
}
return(TRUE);
}
//从USB鼠标设备中读出数据，产生相应的鼠标事件。
BOOLCMouse::SubmitInterrupt()
{
if(m_hInterruptTransfer)
(*m_lpUsbFuncs->lpCloseTransfer)(m_hInterruptTransfer);
//从USB鼠标PIPE中读数据
m_hInterruptTransfer=(*m_lpUsbFuncs->lpIssueInterruptTransfer)
(m_hInterruptPipe,MouseTransferCompleteStub,this,
USB_IN_TRANSFER|USB_SHORT_TRANSFER_OK,//表示读数据
min(m_pInterface->lpEndpoints[0].Descriptor.wMaxPacketSize,
sizeof(m_pbDataBuffer)),
m_pbDataBuffer,
NULL);
if(m_hInterruptTransfer==NULL)
{
DEBUGMSG(ZONE_ERROR，（L"!USBMouse:ErrorinIssueInterruptTransferrn"));
returnFALSE;
}
else
{
DEBUGMSG(ZONE_TRANSFER,(L"USBMouse::SubmitInterrupt,Transfer:0x%Xrn",
m_hInterruptTransfer));
}
returnTRUE;
}
//处理鼠标中断传输的数据
BOOLCMouse::HandleInterrupt()
{
DWORDdwError;
DWORDdwBytes;
DWORDdwFlags=0;
INTdx=(signedchar)m_pbDataBuffer[1];
INTdy=(signedchar)m_pbDataBuffer[2];
BOOLfButton1=m_pbDataBuffer[0]&0x01?TRUE:FALSE;
BOOLfButton2=m_pbDataBuffer[0]&0x02?TRUE:FALSE;
BOOLfButton3=m_pbDataBuffer[0]&0x04?TRUE:FALSE;
if(!(*m_lpUsbFuncs->lpGetTransferStatus)(m_hInterruptTransfer,&dwBytes,&dwError))
{
DEBUGMSG(ZONE_ERROR,(TEXT("!USBMouse:ErrorinGetTransferStatus(0x%X)rn"),
m_hInterruptTransfer));
returnFALSE;
}
else
{
DEBUGMSG(ZONE_TRANSFER,(TEXT("USBMouse::HandleInterrupt,hTransfer0x%Xcomplete(%ubytes,Error:%X)rn"),
m_hInterruptTransfer,dwBytes,dwError));
}
if(!SubmitInterrupt())
returnFALSE;
if(dwError!=USB_NO_ERROR)
{
DEBUGMSG(ZONE_ERROR,(TEXT("!USBMouse:Error0x%Xininterrupttransferrn"),dwError));
returnTRUE;
}
if(dwBytes<3)
{
DEBUGMSG(ZONE_ERROR,(TEXT("!USBMouse:Invalidbytecnt%ufrominterrupttransferrn"),dwBytes));
returnTRUE;
}
if(dx||dy)
dwFlags|=MOUSEEVENTF_MOVE;
if(fButton1!=m_fPrevButton1)
{
if(fButton1)
dwFlags|=MOUSEEVENTF_LEFTDOWN;
else
dwFlags|=MOUSEEVENTF_LEFTUP;
}
if(fButton2!=m_fPrevButton2)
{
if(fButton2)
dwFlags|=MOUSEEVENTF_RIGHTDOWN;
else
dwFlags|=MOUSEEVENTF_RIGHTUP;
}
if(fButton3!=m_fPrevButton3)
{
if(fButton3)
dwFlags|=MOUSEEVENTF_MIDDLEDOWN;
else
dwFlags|=MOUSEEVENTF_MIDDLEUP;
}
m_fPrevButton1=fButton1;
m_fPrevButton2=fButton2;
m_fPrevButton3=fButton3;
DEBUGMSG(ZONE_EVENTS,
(TEXT("USBMouseevent:dx:%d,dy:%d,dwFlags:0x%X(B1:%u,B2:%u,B3:%u)rn"),
dx,dy,dwFlags,fButton1,fButton2,fButton3));
//通知系统产生鼠标事件
if(m_fReadyForMouseEvents)
mouse_event(dwFlags,dx,dy,0,0);
else
m_fReadyForMouseEvents=IsAPIReady(SH_WMGR);
returnTRUE;
}
DWORDCALLBACKCMouse::MouseTransferCompleteStub(LPVOIDlpvNotifyParameter)
{
CMouse*pMouse=(CMouse*)lpvNotifyParameter;
return(pMouse->MouseTransferComplete());
}
//数据传输完毕回调函数
DWORDCMouse::MouseTransferComplete()
{
if(m_hEvent)
SetEvent(m_hEvent);
return0;
}
ULONGCALLBACKCMouse::MouseThreadStub(PVOIDcontext)
{
CMouse*pMouse=(CMouse*)context;
return(pMouse->MouseThread());
}
//USB鼠标线程
DWORDCMouse::MouseThread()
{
DEBUGMSG(ZONE_INIT,(TEXT("USBMouse:Workerthreadstartedrn")));
SetThreadPriority(GetCurrentThread(),THREAD_PRIORITY_HIGHEST);[!--empirenews.page--]
if(SubmitInterrupt())
{
while(!m_fClosing)
{
WaitForSingleObject(m_hEvent,INFINITE);
if(m_fClosing)
break;
if((*m_lpUsbFuncs->lpIsTransferComplete)(m_hInterruptTransfer))
{
if(!HandleInterrupt())
break;
}
else
{
RETAILMSG(1,(TEXT("!USBMouse:Eventsignalled,buttransfernotcompletern")));
//Theonlytimethisshouldhappenisifwegetanerroronthetransfer
ASSERT(m_fClosing||(m_hInterruptTransfer==NULL));
break;
}
}
}
RETAILMSG(1,(TEXT("USBMouse:Workerthreadexitingrn")));
return(0);
}
看到了没有，其实USB的驱动程序编写就这么简单，类似的其他设备，例如打印机设备，就有BulkOUTPIPE，需要Bulk传输，那就需要了解一下IssueBulkTransfer（）的应用。当然如果是开发USBMassStorageDisk的驱动，那就需要了解更多的协议，例如Bulk-OnlyTransport协议等。
微软的WindowsCE.NET的PlatformBuild中已经带有USBPrinter和USBMassStorageDisk的驱动的源代码了，好好研究一下，你一定回受益非浅的。
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