PCI(Peripheral Component Interconnect)总线标准是一种将系统外部设备连接起来的总线标准，速度可以达到133MB/s，它是PC中最重要的总线，其他总路线如ISA总线，USB总线等，都挂载在PCI总线上（通过桥接电路）。由Intel推出的一种局部总线，为32位数据地址总线，可以扩展为64位，支持突发读写，及多组外围设备。
在PCI系统中，Host/PCI称为北桥，连接主处理器总线到基础PCI局部总线；PCI-ISA桥称为南桥，连接基础PCI总线到ISA总线。其中南桥通常还含有中断控制器，IDE控制器，USB控制器和DMA控制器等设备。
图示 P412
PCI有三个相互独立的物理地址空间：设备存储器地址空间，I/O地址空间和配置空间。由于PCI支持设备即插即用，所以PCI设备不占用固定的内存地址空间或I/O地址空间，而是可以由操作系统决定其映射的基址。
PCI总线规范定义的配置Hha总长度为256个字节，配置信息按一定的顺序和大小依次存放。根据读取PCI配置空间，可以得到PCI设备的所有资源。[1]中讲述了多种读取PCI配置空间的方法，包括通过最基本的I/O端口操作进行读取，通过DDK提供的函数HalGetBusData,HalSetBusData在NT式驱动中进行读取，在WDM驱动中的读取方法，等。
一般程序所看到的内存指针都是虚拟内存，如果想操作物理内存，必须使用DDK提供的内核函数WRITE_REGISTER_XX,READ_REGISTER_XX系列函数。
MmAllocateContiguousMemory分配连续的物理地址，MmGetPhysicalAddress得到连续的物理内存地址。
代码
#pragma PAGEDCODE
NTSTATUS InitMyPCI(IN PDEVICE_EXTENSION pdx,IN PCM_PARTIAL_RESOURCE_LIST list)
{
PDEVICE_OBJECT fdo = pdx->fdo;
ULONG vector;
KIRQL irql;
KINTERRUPT_MODE mode;
KAFFINITY affinity;
BOOLEAN irqshare;
BOOLEAN gotinterrupt = FALSE;
PHYSICAL_ADDRESS portbase;
BOOLEAN gotport = FALSE;
PCM_PARTIAL_RESOURCE_DESCRIPTOR resource = &list->PartialDescriptors[0];
ULONG nres = list->Count;
BOOLEAN IsMem0 = TRUE;
for (ULONG i = 0; i < nres; ++i, ++resource)
{ // for each resource
switch (resource->Type)
{ // switch on resource type
case CmResourceTypePort:
portbase = resource->u.Port.Start;
pdx->nports = resource->u.Port.Length;
pdx->mappedport = (resource->Flags & CM_RESOURCE_PORT_IO) == 0;
gotport = TRUE;
break;
case CmResourceTypeMemory:
if (IsMem0)
{
pdx->MemBar0 = (PUCHAR)MmMapIoSpace(resource->u.Memory.Start,
resource->u.Memory.Length,
MmNonCached);
pdx->nMem0 = resource->u.Memory.Length;
IsMem0 = FALSE;
}else
{
pdx->MemBar1 = (PUCHAR)MmMapIoSpace(resource->u.Memory.Start,
resource->u.Memory.Length,
MmNonCached);
pdx->nMem1 = resource->u.Memory.Length;
}
break;
case CmResourceTypeInterrupt:
irql = (KIRQL) resource->u.Interrupt.Level;
vector = resource->u.Interrupt.Vector;
affinity = resource->u.Interrupt.Affinity;
mode = (resource->Flags == CM_RESOURCE_INTERRUPT_LATCHED)
? Latched : LevelSensitive;
irqshare = resource->ShareDisposition == CmResourceShareShared;
gotinterrupt = TRUE;
break;
default:
KdPrint(("Unexpected I/O resource type %d\n", resource->Type));
break;
} // switch on resource type
} // for each resource
if (!(TRUE&& gotport&& gotinterrupt ))
{
KdPrint((" Didn't get expected I/O resources\n"));
return STATUS_DEVICE_CONFIGURATION_ERROR;
}
if (pdx->mappedport)
{ // map port address for RISC platform
pdx->portbase = (PUCHAR) MmMapIoSpace(portbase, pdx->nports, MmNonCached);
if (!pdx->mappedport)
{
KdPrint(("Unable to map port range %I64X, length %X\n", portbase, pdx->nports));
return STATUS_INSUFFICIENT_RESOURCES;
}
} // map port address for RISC platform
else
pdx->portbase = (PUCHAR) portbase.QuadPart;
NTSTATUS status = IoConnectInterrupt(&pdx->InterruptObject, (PKSERVICE_ROUTINE) OnInterrupt,
(PVOID) pdx, NULL, vector, irql, irql, LevelSensitive, TRUE, affinity, FALSE);
if (!NT_SUCCESS(status))
{
KdPrint(("IoConnectInterrupt failed - %X\n", status));
if (pdx->portbase && pdx->mappedport)
MmUnmapIoSpace(pdx->portbase, pdx->nports);
pdx->portbase = NULL;
return status;
}
#define IMAGE_LENGTH (640*480)
//申请一段连续物理地址来读取图像
PHYSICAL_ADDRESS maxAddress;
maxAddress.u.LowPart = 0xFFFFFFFF;
maxAddress.u.HighPart = 0;
pdx->MemForImage = MmAllocateContiguousMemory(IMAGE_LENGTH,maxAddress);
PHYSICAL_ADDRESS pycialAddressForImage = MmGetPhysicalAddress(pdx->MemForImage);
WRITE_REGISTER_BUFFER_UCHAR((PUCHAR)pdx->MemBar0+0x10000,
(PUCHAR)&pycialAddressForImage.u.LowPart,4);
return STATUS_SUCCESS;
}
参考
[1] Windows 驱动开发技术详解，张帆