[U-Boot-Users] about "flash extend data"

[孙 彬]

/*******************************************************************************
* flashDataExt - Extend Data. 
* DESCRIPTION:
*    Should be used only for FLASH CFI command sequence.
*
*     Prepare the Data according to the Flash Width and Bus Width.            
*     If flash width = 2 and bus width = 1 data = 0x55 -> data = 0x55        
*     If flash width = 2 and bus width = 4 data = 0x55 -> data = 0x550055        
*     If flash width = 1 and bus width = 4 data = 0x55 -> data = 0x55555555    
*
* INPUT:
*       data    - Data to be expended.
*    pFlash    - flash information.
*
* OUTPUT:
*    None
*
* RETURN:
*    MV_U32     - Data after extension.
*    OxFFFFFFFF if pFlash is Null
*
*******************************************************************************/
MV_U32 flashDataExt( MV_FLASH_INFO *pFlash, MV_U32 data)
{
    MV_U32    i;
    if(NULL == pFlash)
        return 0xFFFFFFFF;

    for(i = 0; i < pFlash->busWidth ; i+= pFlash->devWidth)
    {
        data |= data << 8*i; 
    }
    return data;
}


This is the code of flash initialization in u-boot,i am not sure what's use of the extend data.

regards 
sun

       
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