wince -- 2410-gpio的驱动

在WINCE下能够直接访问的都是虚拟地址，不能直接访问GPIO端口，因此我们首先需要将GPIO口的物理地址映射到虚拟地址上来。
    分别使用VirtualAlloc和VirtualCopy这两个函数来完成映射！
这两个函数的原型：
LPVOID VirtualAlloc(      LPVOID lpAddress,        DWORD dwSize,
DWORD flAllocationType,    DWORD flProtect );
BOOL VirtualCopy( LPVOID lpvDest, LPVOID lpvSrc, DWORD cbSize, DWORD fdwProtect );
如果这两个函数执行成功，哪么VirtualAlloc将返回一个指针，使用这个指针我们就可以直接访问GPIO，通过读写相关地址寄存器，来控制GPIO端口！
   v_pIOPregs = (volatile IOPreg *)VirtualAlloc(0, sizeof(IOPreg), MEM_RESERVE, PAGE_NOACCESS);
          if (v_pIOPregs == NULL){
                    RetValue = FALSE;
          }
          else {
                    if (!VirtualCopy((PVOID)v_pIOPregs, (PVOID)(IOP_BASE), sizeof(IOPreg), PAGE_READWRITE | PAGE_NOCACHE)) {
                             RetValue = FALSE;
                    }
          }
          if (!RetValue){
                    //PIO_InitializeAddresses - Failed !!
          if (v_pIOPregs){
                             VirtualFree((PVOID) v_pIOPregs, 0, MEM_RELEASE);
                    }
                    v_pIOPregs = NULL;
          }
          //else RETAILMSG (1, (TEXT("::: PBT_InitializeAddresses - Success\r\n") ));
          return(RetValue);
v_pIOPregs是一个IOPreg结构，在s2410.h中定义，
//
// Registers : I/O port
#define IOP_BASE       0xB1600000 // 0x56000000
typedef struct   {
     unsigned int   rGPACON;                   // 00
     unsigned int   rGPADAT;
     unsigned int   rPAD1[2];
    
     unsigned int   rGPBCON;                   // 10
     unsigned int   rGPBDAT;
     unsigned int   rGPBUP;
     unsigned int   rPAD2;
    
     unsigned int   rGPCCON;                   // 20
     unsigned int   rGPCDAT;
     unsigned int   rGPCUP;
     unsigned int   rPAD3;
    
     unsigned int   rGPDCON;                   // 30
     unsigned int   rGPDDAT;
     unsigned int   rGPDUP;
     unsigned int   rPAD4;
    
     unsigned int   rGPECON;                   // 40
     unsigned int   rGPEDAT;
     unsigned int   rGPEUP;
     unsigned int   rPAD5;
    
     unsigned int   rGPFCON;                    // 50
     unsigned int   rGPFDAT;
     unsigned int   rGPFUP;
     unsigned int   rPAD6;
    
     unsigned int   rGPGCON;                   // 60
     unsigned int   rGPGDAT;
     unsigned int   rGPGUP;
     unsigned int   rPAD7;
    
     unsigned int   rGPHCON;                   // 70
     unsigned int   rGPHDAT;
     unsigned int   rGPHUP;
     unsigned int   rPAD8;
    
     unsigned int   rMISCCR;           // 80
     unsigned int   rDCKCON;                  
     unsigned int   rEXTINT0;
     unsigned int   rEXTINT1;                   
     unsigned int   rEXTINT2;                    // 90
          unsigned int   rEINTFLT0;
          unsigned int   rEINTFLT1;
          unsigned int   rEINTFLT2;
          unsigned int   rEINTFLT3;                  // A0
          unsigned int   rEINTMASK;
          unsigned int   rEINTPEND;
          unsigned int   rGSTATUS0;
          unsigned int   rGSTATUS1;                 // B0
}IOPreg;