wince FAL+FMD的简单分析

wince FAL+FMD的简单分析

creator

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1.首先弄清楚FAL中的设备驱动，物理设备数据类型如下：

typedef struct _DEVICE

{

    DWORD   dwID;

    PVOID   hFMD;

    PVOID   hFMDHook;

} DEVICE , *PDEVICE;

有一个公共变量g_pDevice来保存这个。pDevice指向g_pDevice

2.在DSK_Init初始化化中，会通过GetFMDInterface(pDevice)获得FMD。

VOID GetFMDInterface(PDEVICE pDevice)

{

    FMD.cbSize = sizeof(FMDInterface);

    // query FMD intrface from the FMD    

    FMD.pOEMIoControl = FMD_OEMIoControl;

    if (!FMD_OEMIoControl (IOCTL_FMD_GET_INTERFACE, NULL, 0, (PBYTE)&FMD, sizeof(FMDInterface), NULL))

    {

        // FMD does not support IOCTL_FMD_GET_INTERFACE, so build the FMDInterface 

        // structure using the legacy FMD functions

        FMD.pInit = FMD_Init;

        FMD.pDeInit = FMD_Deinit;

        FMD.pGetInfo = FMD_GetInfo;        

        FMD.pGetBlockStatus = FMD_GetBlockStatus;     

        FMD.pSetBlockStatus = FMD_SetBlockStatus;

        FMD.pReadSector = FMD_ReadSector;

        FMD.pWriteSector = FMD_WriteSector;

        FMD.pEraseBlock = FMD_EraseBlock;

        FMD.pPowerUp = FMD_PowerUp;

        FMD.pPowerDown = FMD_PowerDown;

    }

    // query hook library in case any FMD functions need to be shimmed

    pDevice->hFMDHook = FMDHOOK_HookInterface(&FMD);

}

其中FMD_OEMIoControl是在Fmd.cpp中定义的。通过这个函数把msflash.dll和nandflash.dll联系起来。

通过它获得FMD，是一个函数指针接口，以后就通过FMD来执行FMD中的实际函数了。

BOOL FMD_OEMIoControl(DWORD dwIoControlCode, PBYTE pInBuf, DWORD nInBufSize, PBYTE pOutBuf, DWORD nOutBufSize, PDWORD pBytesReturned)

{

switch(dwIoControlCode)

{

case IOCTL_FMD_GET_INTERFACE:

{

RETAILMSG(1, (TEXT("[FMD] FMD_OEMIoControl() : IOCTL_FMD_GET_INTERFACE\r\n")));

if (!pOutBuf || nOutBufSize < sizeof(FMDInterface))

{

DEBUGMSG(1, (TEXT("FMD_OEMIoControl: IOCTL_FMD_GET_INTERFACE bad parameter(s).\r\n")));

return(FALSE);

}

PFMDInterface pInterface = (PFMDInterface)pOutBuf;

pInterface->cbSize = sizeof(FMDInterface);

pInterface->pInit = FMD_Init;

pInterface->pDeInit = FMD_Deinit;

pInterface->pGetInfo = FMD_GetInfo;

pInterface->pGetInfoEx = NULL; //FMD_GetInfoEx;

pInterface->pGetBlockStatus = FMD_GetBlockStatus;

pInterface->pSetBlockStatus = FMD_SetBlockStatus;

pInterface->pReadSector = FMD_ReadSector;

pInterface->pWriteSector = FMD_WriteSector;

pInterface->pEraseBlock = FMD_EraseBlock;

pInterface->pPowerUp = FMD_PowerUp;

pInterface->pPowerDown = FMD_PowerDown;

pInterface->pGetPhysSectorAddr = NULL;

break;

}

.....

}

3.获得FMD之后，首先调用FMD.pInit， 对FMD设备进行初始化。主要是控制器的配置，读ID得到nandflash的容量，

等信息。

4.调用FMD.pGetInfo(&oldFlashInfo)获得nandflash的信息。最终也是调用BOOL FMD_GetInfo(PFlashInfo pFlashInfo)

pFlashInfo->dwNumBlocks         = NUM_OF_BLOCKS;

pFlashInfo->wSectorsPerBlock    = PAGES_PER_BLOCK;

pFlashInfo->wDataBytesPerSector = NAND_SECTOR_SIZE;

pFlashInfo->dwBytesPerBlock     = (PAGES_PER_BLOCK * NAND_SECTOR_SIZE);

把相关信息读到oldFlashInfo中。然后把相关数据写入公共变量g_pFlashMediaInfo

5.然后通过调用CalculateLogicalRange来统计nandflash的区域大小和可以用的block

BOOL CalculateLogicalRange(PFlashRegion pRegion)

{

    DWORD dwBlockID;

    DWORD dwNumLogicalBlocks = 0;

    

    for (dwBlockID = pRegion->dwStartPhysBlock; dwBlockID < pRegion->dwStartPhysBlock + pRegion->dwNumPhysBlocks; dwBlockID++)

    {

        DWORD dwStatus = FMD.pGetBlockStatus (dwBlockID);

        if (!(dwStatus & (BLOCK_STATUS_RESERVED | BLOCK_STATUS_BAD)))

        {

            dwNumLogicalBlocks++;

        }

    }

    //pRegion->dwCompactBlocks=MINIMUM_FLASH_BLOCKS_TO_RESERVE最少的block为2，如果wince发现少于2个block的可用块，就会返回error。

    if (dwNumLogicalBlocks <= pRegion->dwCompactBlocks)

    {

        ReportError((TEXT("FLASHDRV.DLL:CalculateLogicalRange() - Invalid number of logical blocks %d\r\n"), dwNumLogicalBlocks));

        return FALSE;

    }

    // Account for compaction blocks

    dwNumLogicalBlocks -= pRegion->dwCompactBlocks;

    pRegion->dwNumLogicalBlocks = dwNumLogicalBlocks;

    return TRUE;

}

最终也是调用FMD_GetBlockStatus函数。