Question

我需要在运行Windows Embedded Compact 2013的平台上以用户模式访问物理内存。我发现了一篇文章。内存映射在内核模式驱动程序中完成，地址返回给用户模式程序。

在内核驱动程序中

BOOL BTN_IOControl(DWORD context, DWORD code, UCHAR *pInBuffer, DWORD inSize, UCHAR *pOutBuffer,DWORD outSize, DWORD *pOutSize)
{

      PDWORD tValue = (PDWORD)pOutBuffer;
          switch(code)
          {

           case IOCTL_MAP_MEMORY:
               *tValue = GetVirtualAddress();
               *pOutSize = 4;
                break;
           .....
}

GetVirtualMemory函数如下

LPOID GetVirtualAddress()
{
    volatile DWORD sDevPhysAddr = 0xe000a000;
    volatile DWORD dwSize = PAGE_SIZE;

    LPVOID lpUserAddr;
    volatile ULONG SourceSize;
    volatile ULONG SourcePhys;
    void* pvProcess = (void*)GetCallerVMProcessId();
    SourcePhys = sDevPhysAddr & ~(PAGE_SIZE - 1);
    SourceSize = PAGE_SIZE;
    RETAILMSG(1, (L"Address: %08x Size: %08x.\r\n", SourcePhys, SourceSize));

    lpUserAddr = (LPDWORD)VirtualAllocEx(pvProcess, 0, SourceSize, MEM_RESERVE, PAGE_NOACCESS);
    if (lpUserAddr == NULL) {
        RETAILMSG(1, (L"VirtualAllocEx failed. GetLastError %d.\r\n", GetLastError()));
        return NULL;
    }

    if (!VirtualCopyEx(pvProcess, lpUserAddr, GetCurrentProcess(), (PVOID)
    /*(*/SourcePhys/* >> 8)*/, SourceSize,
    /*PAGE_PHYSICAL | */PAGE_READWRITE | PAGE_NOCACHE)) {
     RETAILMSG(1, (L"VirtualCopyEx failed. Error %d.\r\n", GetLastError()));
    return NULL;
     }
     RETAILMSG(1, (L"Before round up lpUserAddr=0x%x\r\n", lpUserAddr));
     lpUserAddr = (LPVOID)((ULONG)lpUserAddr + (sDevPhysAddr & (PAGE_SIZE - 1)));
     shared_mem = lpUserAddr;
     RETAILMSG(1, (L"After round up gUserAddr=0x%x\r\n", shared_mem));
     return lpUserAddr;
 }

代码映射物理内存0xe000a000（zynq芯片中的GPIO基地址）。 VirtualCopyEx中的代码失败，错误为87（参数无效）。但代码使用基本物理地址0x81F00000（此地址由原始程序员使用）。我的问题是如何启用GPIO地址的映射。我也愿意尝试任何其他方法。

Answer 1

经过长时间的斗争，我找到了答案。

 DWORD GetVirtualAddress()
 {
      HANDLE hCurrentProcess;
      HANDLE hCallerProcess;
      DWORD pAddr;
      PHYSICAL_ADDRESS pa;
      hCurrentProcess = (HANDLE)GetCurrentProcess();
      hCallerProcess = (HANDLE)GetDirectCallerProcessId();
      pa.QuadPart = 0xe000a000;
      pGpioRegs = MmMapIoSpace(pa, sizeof(XILINX_GPIO_REGS), FALSE);
      if (!pGpioRegs)
           RETAILMSG(1, (L"Cannot map the gpio register.\r\n"));
      pAddr = (DWORD)VirtualAllocCopyEx(hCurrentProcess, hCallerProcess, pGpioRegs,
               PAGE_SIZE, PAGE_READWRITE | PAGE_NOCACHE);
      if (!pAddr)
         RETAILMSG(1, (L"VirtualAllocCopy: Error: %d.\r\n", GetLastError()));
       return pAddr;
}

这将返回给DeviceIoControl上的调用者调用映射到设备基址的物理地址的虚拟地址。

Windows CE：以用户模式映射物理内存

1 个答案: