windows 访问pcie配置空间代码

以下是在 Windows 上访问 PCIe 配置空间的示例代码：

#include <windows.h>
#include <winioctl.h>
#include <cstdio>

#define IOCTL_READ_PCI_CONFIG    CTL_CODE(FILE_DEVICE_UNKNOWN, 0x800, METHOD_BUFFERED, FILE_ANY_ACCESS)
#define IOCTL_WRITE_PCI_CONFIG   CTL_CODE(FILE_DEVICE_UNKNOWN, 0x801, METHOD_BUFFERED, FILE_ANY_ACCESS)

typedef struct _PCI_CONFIG_IN {
    ULONG BusNumber;
    ULONG DeviceNumber;
    ULONG FunctionNumber;
    ULONG Offset;
    ULONG Length;
} PCI_CONFIG_IN, *PPCI_CONFIG_IN;

typedef struct _PCI_CONFIG_OUT {
    ULONG Data;
} PCI_CONFIG_OUT, *PPCI_CONFIG_OUT;

int main() {
    HANDLE hDevice;
    DWORD bytesReturned;
    PCI_CONFIG_IN inBuf;
    PCI_CONFIG_OUT outBuf;

    // 打开设备
    hDevice = CreateFile(TEXT("\\\\.\\PCI"), GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    if (hDevice == INVALID_HANDLE_VALUE) {
        printf("Failed to open device.\n");
        return -1;
    }

    // 读取配置空间
    inBuf.BusNumber = 0;
    inBuf.DeviceNumber = 0;
    inBuf.FunctionNumber = 0;
    inBuf.Offset = 0;
    inBuf.Length = 4;  // 读取 4 字节
    if (DeviceIoControl(hDevice, IOCTL_READ_PCI_CONFIG, &inBuf, sizeof(inBuf), &outBuf, sizeof(outBuf), &bytesReturned, NULL)) {
        printf("Read data = 0x%x\n", outBuf.Data);
    } else {
        printf("Failed to read PCI config space.\n");
    }

    // 写入配置空间
    inBuf.BusNumber = 0;
    inBuf.DeviceNumber = 0;
    inBuf.FunctionNumber = 0;
    inBuf.Offset = 0x10;  // 写入偏移地址为 0x10 的位置
    inBuf.Length = 4;  // 写入 4 字节
    outBuf.Data = 0x12345678;  // 写入数据
    if (DeviceIoControl(hDevice, IOCTL_WRITE_PCI_CONFIG, &inBuf, sizeof(inBuf), &outBuf, sizeof(outBuf), &bytesReturned, NULL)) {
        printf("Write data successfully.\n");
    } else {
        printf("Failed to write PCI config space.\n");
    }

    // 关闭设备
    CloseHandle(hDevice);

    return 0;
}

上述代码打开了一个名称为“\\.\PCI”的设备，并通过 `DeviceIoControl` 函数执行了读取和写入 PCIe 配置空间的操作。其中 `IOCTL_READ_PCI_CONFIG` 和 `IOCTL_WRITE_PCI_CONFIG` 是自定义的控制码，可用于识别要执行的操作类型。具体的偏移地址、总线号、设备号、功能号等参数需要根据实际情况进行设置。