reactos操作系统实现(148)

来源：互联网发布：洪泽新闻网农村淘宝编辑：程序博客网时间：2024/05/01 06:00

在小端口驱动程序里，主要调用视频驱动程序API来实现相关的功能，下面就来分析小端口驱动程序里调用的初始化函数VideoPortInitialize，它的实现代码在文件reactos/drivers/video/videoprt/videoprt.c里，如下：

#001 ULONG NTAPI

#002 VideoPortInitialize(

#003 IN PVOID Context1,

#004 IN PVOID Context2,

#005 INPVIDEO_HW_INITIALIZATION_DATA HwInitializationData,

#006 IN PVOID HwContext)

#007 {

驱动程序对象参数。

#008 PDRIVER_OBJECTDriverObject = Context1;

注册表路径。

#009 PUNICODE_STRINGRegistryPath = Context2;

#010 NTSTATUS Status;

#011 PVIDEO_PORT_DRIVER_EXTENSION DriverExtension;

#012 BOOLEAN PnpDriver =FALSE, LegacyDetection = FALSE;

#013

#014 TRACE_(VIDEOPRT,"VideoPortInitialize/n");

#015

#016 /*

#017 * As a first thing doparameter checks.

#018 */

#019

首先做参数检查，如果失败就返回出错。

#020 if(HwInitializationData->HwInitDataSize >sizeof(VIDEO_HW_INITIALIZATION_DATA))

#021 {

#022 return STATUS_REVISION_MISMATCH;

#023 }

#024

#025 if(HwInitializationData->HwFindAdapter == NULL ||

#026 HwInitializationData->HwInitialize == NULL ||

#027 HwInitializationData->HwStartIO == NULL)

#028 {

#029 returnSTATUS_INVALID_PARAMETER;

#030 }

#031

根据初始化的数据结构大小来区分不同的系统版本。

#032 switch(HwInitializationData->HwInitDataSize)

#033 {

#034 /*

#035 * NT4 drivers arespecial case, because we must use legacy method

#036 * of detectioninstead of the Plug & Play one.

#037 */

#038

#039 caseSIZE_OF_NT4_VIDEO_HW_INITIALIZATION_DATA:

#040 INFO_(VIDEOPRT,"We were loaded by a Windows NT miniport driver./n");

#041 break;

#042

#043 case SIZE_OF_W2K_VIDEO_HW_INITIALIZATION_DATA:

#044 INFO_(VIDEOPRT,"We were loaded by a Windows 2000 miniport driver./n");

#045 break;

#046

#047 casesizeof(VIDEO_HW_INITIALIZATION_DATA):

#048 INFO_(VIDEOPRT,"We were loaded by a Windows XP or later miniport driver./n");

#049 break;

#050

#051 default:

#052 WARN_(VIDEOPRT,"Invalid HwInitializationData size./n");

#053 returnSTATUS_UNSUCCESSFUL;

#054 }

#055

设置驱动程序处理功能函数。

#056 /* Set dispatchingroutines */

#057 DriverObject->MajorFunction[IRP_MJ_CREATE] =IntVideoPortDispatchOpen;

#058 DriverObject->MajorFunction[IRP_MJ_CLOSE] =IntVideoPortDispatchClose;

#059 DriverObject->MajorFunction[IRP_MJ_DEVICE_CONTROL] =

#060 IntVideoPortDispatchDeviceControl;

#061 DriverObject->MajorFunction[IRP_MJ_INTERNAL_DEVICE_CONTROL] =

#062 IntVideoPortDispatchDeviceControl;

#063 DriverObject->MajorFunction[IRP_MJ_WRITE] =

#064 IntVideoPortDispatchWrite; // ReactOS-specific hack

#065 DriverObject->DriverUnload = IntVideoPortUnload;

#066

检查小端口驱动程序是什么类型。

#067 /* Determine type of theminiport driver */

#068 if((HwInitializationData->HwInitDataSize >=

#069 FIELD_OFFSET(VIDEO_HW_INITIALIZATION_DATA, HwQueryInterface))

#070 &&HwInitializationData->HwSetPowerState

#071 &&HwInitializationData->HwGetPowerState

#072 &&HwInitializationData->HwGetVideoChildDescriptor)

#073 {

这里检测到小端口驱动程序是即插即用驱动程序。

#074 INFO_(VIDEOPRT,"The miniport is a PnP miniport driver/n");

#075 PnpDriver = TRUE;

#076 }

#077

检查是否旧的驱动程序模式。

#078 /* Check if legacydetection should be applied */

#079 if (!PnpDriver ||HwContext)

#080 {

#081 INFO_(VIDEOPRT,"Legacy detection for adapter interface %d/n",

#082 HwInitializationData->AdapterInterfaceType);

#083

#084 /* FIXME: Move thecode for legacy detection

#085 to anotherfunction and call it here */

#086 LegacyDetection =TRUE;

#087 }

#088

#089 /*

#090 * NOTE:

#091 * The driver extensioncan be already allocated in case that we were

#092 * called by legacydriver and failed detecting device. Some miniport

#093 * drivers in that caseadjust parameters and call VideoPortInitialize

#094 * again.

#095 */

#096

尝试获取驱动程序扩展数据。

#097 DriverExtension =IoGetDriverObjectExtension(DriverObject, DriverObject);

#098 if (DriverExtension ==NULL)

#099 {

如果没有分配驱动程序扩展，就在这里分配。

#100 Status = IoAllocateDriverObjectExtension(

#101 DriverObject,

#102 DriverObject,

#103 sizeof(VIDEO_PORT_DRIVER_EXTENSION),

#104 (PVOID*)&DriverExtension);

#105

#106 if(!NT_SUCCESS(Status))

#107 {

#108 return Status;

#109 }

#110

#111 /*

#112 * Save the registrypath. This should be done only once even if

#113 * VideoPortInitializeis called multiple times.

#114 */

#115

保存当前驱动程序在注册表里的路径。

#116 if (RegistryPath->Length != 0)

#117 {

#118 DriverExtension->RegistryPath.Length = 0;

#119 DriverExtension->RegistryPath.MaximumLength =

#120 RegistryPath->Length + sizeof(UNICODE_NULL);

#121 DriverExtension->RegistryPath.Buffer=

#122 ExAllocatePoolWithTag(

#123 PagedPool,

#124 DriverExtension->RegistryPath.MaximumLength,

#125 TAG('U', 'S','T', 'R'));

#126 if(DriverExtension->RegistryPath.Buffer == NULL)

#127 {

#128 RtlInitUnicodeString(&DriverExtension->RegistryPath, NULL);

#129 returnSTATUS_INSUFFICIENT_RESOURCES;

#130 }

#131

#132 RtlCopyUnicodeString(&DriverExtension->RegistryPath,RegistryPath);

#133 INFO_(VIDEOPRT,"RegistryPath: %wZ/n", &DriverExtension->RegistryPath);

#134 }

#135 else

#136 {

#137 RtlInitUnicodeString(&DriverExtension->RegistryPath, NULL);

#138 }

#139 }

#140

#141 /*

#142 * Copy the correctminiport initialization data to the device extension.

#143 */

#144

拷贝初始化数据。

#145 RtlCopyMemory(

#146 &DriverExtension->InitializationData,

#147 HwInitializationData,

#148 HwInitializationData->HwInitDataSize);

#149 if(HwInitializationData->HwInitDataSize <

#150 sizeof(VIDEO_HW_INITIALIZATION_DATA))

#151 {

#152 RtlZeroMemory((PVOID)((ULONG_PTR)&DriverExtension->InitializationData+

#153 HwInitializationData->HwInitDataSize),

#154 sizeof(VIDEO_HW_INITIALIZATION_DATA) -

#155 HwInitializationData->HwInitDataSize);

#156 }

#157 DriverExtension->HwContext = HwContext;

#158

#159 /*

#160 * Plug & Playdrivers registers the device in AddDevice routine. For

#161 * legacy drivers we mustdo it now.

#162 */

#163

旧的驱动程序进行功能回调函数设置。

#164 if (LegacyDetection)

#165 {

#166 PDEVICE_OBJECTDeviceObject;

#167

#168 if(HwInitializationData->HwInitDataSize !=SIZE_OF_NT4_VIDEO_HW_INITIALIZATION_DATA)

#169 {

#170 /* powermanagement */

#171 DriverObject->MajorFunction[IRP_MJ_POWER] =IntVideoPortDispatchPower;

#172 }

#173 Status =IntVideoPortCreateAdapterDeviceObject(DriverObject, DriverExtension,

#174 NULL, &DeviceObject);

#175 INFO_(VIDEOPRT,"IntVideoPortCreateAdapterDeviceObject returned 0x%x/n", Status);

#176 if(!NT_SUCCESS(Status))

#177 return Status;

这里调用函数IntVideoPortFindAdapter来注册本显示驱动程序到对象管理器，以便创建设备DC时使用。

#178 Status =IntVideoPortFindAdapter(DriverObject, DriverExtension, DeviceObject);

#179 INFO_(VIDEOPRT,"IntVideoPortFindAdapter returned 0x%x/n", Status);

#180 if(NT_SUCCESS(Status))

#181 VideoPortDeviceNumber++;

#182 return Status;

#183 }

#184 else

#185 {

即插即用的驱动程序的回调函数设置。

#186 DriverObject->DriverExtension->AddDevice = IntVideoPortAddDevice;

#187 DriverObject->MajorFunction[IRP_MJ_PNP] = IntVideoPortDispatchPnp;

#188 DriverObject->MajorFunction[IRP_MJ_POWER] =IntVideoPortDispatchPower;

#189 DriverObject->MajorFunction[IRP_MJ_SYSTEM_CONTROL] =IntVideoPortDispatchSystemControl;

#190

#191 return STATUS_SUCCESS;

#192 }

#193 }