reactos操作系统实现(148)

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 IN
PVIDEO_HW_INITIALIZATION_DATA HwInitializationData,
#006 IN PVOID HwContext)
#007 {

驱动程序对象参数。
#008 PDRIVER_OBJECT
DriverObject = Context1;

注册表路径。
#009 PUNICODE_STRING
RegistryPath = 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 do
parameter 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 return
STATUS_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 are
special case, because we must use legacy method
#036 * of detection
instead of the Plug & Play one.
#037 */
#038
#039 case
SIZE_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 case
sizeof(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 return
STATUS_UNSUCCESSFUL;
#054 }
#055

设置驱动程序处理功能函数。
#056 /* Set dispatching
routines */
#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 the
miniport 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 legacy
detection 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 the
code for legacy detection
#085 to another
function and call it here */
#086 LegacyDetection =
TRUE;
#087 }
#088
#089 /*
#090 * NOTE:
#091 * The driver extension
can be already allocated in case that we were
#092 * called by legacy
driver and failed detecting device. Some miniport
#093 * drivers in that case
adjust 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 registry
path. This should be done only once even if
#113 * VideoPortInitialize
is 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 return
STATUS_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 correct
miniport 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 & Play
drivers registers the device in AddDevice routine. For
#161 * legacy drivers we must
do 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_OBJECT
DeviceObject;
#167
#168 if
(HwInitializationData->HwInitDataSize !=
SIZE_OF_NT4_VIDEO_HW_INITIALIZATION_DATA)
#169 {
#170 /* power
management */
#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 }