核心模式驱动程式框架

核心模式驱动程式框架Kernel-Mode Driver Framework,缩写KMDF)是微软公司推出的Windows驱动程式基础(Windows Driver Foundation)之一,建构Windows XPWindows Server 2003的核心模式(Kernel-Mode)驱动程式所需的基本功能,包括对即插即用(PNP)、电源管理(Power Manager)、I/O队列、直接存储器存取(DMA)、Windows Management Instrumentation(WMI)和同步处理等的完整支持。KMDF的设计并不能用来取代WDM,它提供“Skeletal WDM”建置来替代WDM;目前,KMDF并不支持总线筛选驱动程式(Bus Filter Driver)。

Kernel-Mode Driver Framework目前支持下列类型的核心模式(kernel mode)驱动程式之创建了:

  • 即插即用(PNP)设备所使用的Function Driver。
  • 即插即用(PNP)设备所使用的Filter Driver。
  • 即插即用(PNP)设备堆栈(Stack)所使用的Bus Driver。
  • Windows NT 4.0类型设备所使用的Control设备驱动程式。

KMDF是可重新进入程序库(Reentrant Library)。

与WDM的关系

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自Windows 2000开始,开发驱动程式必以WDM为基础的,但开发难度太大,无法像用户模式应用程式开发那样容易。KMDF支持驱动程式在Windows Driver Model环境中撰写驱动程式,简化其中的过程,但是KMDF的设计并不能用来取代WDM,它提供“Skeletal WDM”建置来替代WDM。早期的WDM可支持Windows 98Windows MeWindows 2000Windows XP;至于WDF计划支持Windows XP,以及更新的版本。

KMDF系以物件为基底创建于WDM框架之上。不同的功能有不同的物件,KMDF在实现上包含了:

驱动程式进入点

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在Windows操作系统中驱动程式的起始点都是在DriverEntry函数,DriveryEntry是驱动程式的进入点(entry point)。在DriverEntry函数的实现里,你需要具现化(instantiate)你的WDFDRIVER物件,并且告知WDF framework要去哪里调用你的系统。

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

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EvtDeviceAdd函数,在系统发现新硬件插入时被调用。这个函数将挑起WDF驱动程式框架的大部分工作,EvtDeviceAdd事件被唤起之余一定会带出一个WDFDRIVER物件,并且指向一个WDFDEVICE_INIT结构。在设备产生(device crated)之前,必先进行初始化的动作。如果EvtDeviceAdd执行成功,那么EvtDevicePrepareHardware是框架下一个被执行的函数,用以保证驱动程式能够访问硬件。

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

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如果EvtDeviceAdd顺利执行成功,那么EvtDevicePrepareHardware是框架下一个被执行的函数,用以保证驱动程式能够访问硬件。

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

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VOID EvtDeviceIoDefault(
   IN WDFQUEUE  Queue,
   IN WDFREQUEST  Request
   )
{
 WdfRequestComplete(Request, STATUS_NOT_IMPLEMENTED);
}

外部链接

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