核心模式驅動程式架構
核心模式驅動程式架構(Kernel-Mode Driver Framework,縮寫KMDF)是微軟公司推出的Windows驅動程式基礎(Windows Driver Foundation)之一,建構Windows XP與Windows Server 2003的核心模式(Kernel-Mode)驅動程式所需的基本功能,包括對隨插即用(PNP)、電源管理(Power Manager)、I/O佇列、直接記憶體存取(DMA)、Windows Management Instrumentation(WMI)和同步處理等的完整支援。KMDF的設計並不能用來取代WDM,它提供「Skeletal WDM」建置來替代WDM;目前,KMDF並不支援匯流排篩選驅動程式(Bus Filter Driver)。
Kernel-Mode Driver Framework目前支援下列類型的核心模式(kernel mode)驅動程式之建立了:
- 隨插即用(PNP)裝置所使用的Function Driver。
- 隨插即用(PNP)裝置所使用的Filter Driver。
- 隨插即用(PNP)裝置堆疊(Stack)所使用的Bus Driver。
- Windows NT 4.0型態裝置所使用的Control裝置驅動程式。
KMDF是可重新進入程式庫(Reentrant Library)。
與WDM的關係
自Windows 2000開始,開發驅動程式必以WDM為基礎的,但開發難度太大,無法像使用者模式應用程式開發那樣容易。KMDF支援驅動程式在Windows Driver Model環境中撰寫驅動程式,簡化其中的過程,但是KMDF的設計並不能用來取代WDM,它提供「Skeletal WDM」建置來替代WDM。早期的WDM可支援Windows 98、Windows Me、Windows 2000和Windows XP;至於WDF計劃支援Windows XP,以及更新的版本。
KMDF係以物件為基底建立於WDM架構之上。不同的功能有不同的物件,KMDF在實作上包含了:
- 即插即用和電源管理
- I/O隊列
- 直接內存訪問(DMA)
- Windows Management Instrumentation(WMI)
- 同步
驅動程式進入點
在Windows作業系統中驅動程式的起始點都是在DriverEntry函式,DriveryEntry是驅動程式的進入點(entry point)。在DriverEntry函式的實作裡,你需要具現化(instantiate)你的WDFDRIVER物件,並且告知WDF framework要去哪裡呼叫你的系統。
NTSTATUS DriverEntry( IN PDRIVER_OBJECT DriverObject, IN PUNICODE_STRING RegistryPath ) { WDF_DRIVER_CONFIG config; NTSTATUS status = S_OK;
KdPrint((__DRIVER_NAME "DriverEntry Begin\n"));
WDF_DRIVER_CONFIG_INIT(&config, EvtDeviceAdd); status = WdfDriverCreate( DriverObject, RegistryPath, WDF_NO_OBJECT_ATTRIBUTES, &config, // Pointer to config structure WDF_NO_HANDLE); // or NULL, Pointer to get WDFDRIVER handle if(T_SUCCESS(status)) { KdPrint((__DRIVER_NAME "WdfDriverCreate failed with status 0x%08x\n", status)); }
KdPrint((__DRIVER_NAME "DriverEntry End\n"));
return status; }
Add Device
EvtDeviceAdd函數,在系統發現新硬體插入時被呼叫。這個函數將挑起WDF驅動程式架構的大部分工作,EvtDeviceAdd事件被喚起之餘一定會帶出一個WDFDRIVER物件,並且指向一個WDFDEVICE_INIT結構。在裝置產生(device crated)之前,必先進行初始化的動作。如果EvtDeviceAdd執行成功,那麼EvtDevicePrepareHardware是架構下一個被執行的函式,用以保證驅動程式能夠訪問硬體。
WDFSTATUS DioEvtDeviceAdd(WDFDRIVER Driver, PWDFDEVICE_INIT DeviceInit) { WDFSTATUS status = STATUS_SUCCESS; WDF_PNPPOWER_EVENT_CALLBACKS pnpPowerCallbacks; WDF_OBJECT_ATTRIBUTES objAttributes; WDFDEVICE device; PDIO_DEVICE_CONTEXT devContext; WDF_IO_QUEUE_CONFIG ioCallbacks; WDF_INTERRUPT_CONFIG interruptConfig; WDF_DEVICE_POWER_POLICY_IDLE_SETTINGS idleSettings;
WDF_PNPPOWER_EVENT_CALLBACKS_INIT(&pnpPowerCallbacks); pnpPowerCallbacks.EvtDevicePrepareHardware = DioEvtPrepareHardware; pnpPowerCallbacks.EvtDeviceReleaseHardware = DioEvtReleaseHardware; pnpPowerCallbacks.EvtDeviceD0Entry= DioEvtDeviceD0Entry; pnpPowerCallbacks.EvtDeviceD0Exit = DioEvtDeviceD0Exit;
WdfDeviceInitSetPnpPowerEventCallbacks(DeviceInit, pnpPowerCallbacks);
WDF_OBJECT_ATTRIBUTES_INIT(&objAttributes);
WDF_OBJECT_ATTRIBUTES_SET_CONTEXT_TYPE(&objAttributes, DIO_DEVICE_CONTEXT);
status = WdfDeviceInitUpdateName(DeviceInit, L"\\device\\WDFDIO");
status = WdfDeviceCreate(&DeviceInit, // Device Init structure &objAttributes, // Attributes for WDF Device &device); // return new WDF Device pointer,
devContext = DioGetContextFromDevice(device); // Get device extension
devContext->WdfDevice = device;
// Create a symbolic link for the control object status = WdfDeviceCreateSymbolicLink(device, L"\\DosDevices\\WDFDIO");
WDF_IO_QUEUE_CONFIG_INIT(&ioCallbacks, WdfIoQueueDispatchSerial, WDF_NO_EVENT_CALLBACK, // StartIo WDF_NO_EVENT_CALLBACK); // CancelRoutine
ioCallbacks.EvtIoDeviceControl = DioEvtDeviceControlIoctl; status = WdfDeviceCreateDefaultQueue(device, &ioCallbacks, WDF_NO_OBJECT_ATTRIBUTES, NULL); // pointer to default queue
WDF_INTERRUPT_CONFIG_INIT(&interruptConfig, // Configure the Interrupt object FALSE, // auto-queue DPC? DioIsr, // ISR DioDpc); // Defered Procedule Call
interruptConfig.EvtInterruptEnable = DioEvtInterruptEnable; interruptConfig.EvtInterruptDisable = DioEvtInterruptDisable;
status = WdfInterruptCreate(device, &interruptConfig, &objAttributes, &devContext->WdfInterrupt);
WDF_DEVICE_POWER_POLICY_IDLE_SETTINGS_INIT(&idleSettings, // Initialize idle policy IdleCannotWakeFromS0);
status = WdfDeviceUpdateS0IdleSettings(device, &idleSettings);
return status; }
Prepare Hardware
如果EvtDeviceAdd順利執行成功,那麼EvtDevicePrepareHardware是架構下一個被執行的函式,用以保證驅動程式能夠訪問硬體。
NTSTATUS EvtDevicePrepareHardware( IN WDFDEVICE Device, IN WDFCMRESLIST ResourceList, IN WDFCMRESLIST ResourceListTranslated ) { NTSTATUS status = STATUS_SUCCESS;
UNREFERENCED_PARAMETER(Device); UNREFERENCED_PARAMETER(ResourceList); UNREFERENCED_PARAMETER(ResourceListTranslated);
return status; }
NTSTATUS EvtDeviceD0Entry( IN WDFDEVICE Device, IN WDF_POWER_DEVICE_STATE PreviousState ) { NTSTATUS status = STATUS_SUCCESS;
return status; }
NTSTATUS EvtDeviceD0Exit( IN WDFDEVICE Device, IN WDF_POWER_DEVICE_STATE TargetState ) { NTSTATUS status = STATUS_SUCCESS;
return status; }
IO requests
VOID EvtDeviceIoDefault( IN WDFQUEUE Queue, IN WDFREQUEST Request ) { WdfRequestComplete(Request, STATUS_NOT_IMPLEMENTED); }