DRESULT disk_register(BYTE drive, DSTATUS(*d_init)(BYTE drive), DSTATUS(*d_status)(BYTE drive), DRESULT(*d_read)(BYTE drive, BYTE *buf, DWORD sector, UINT num), DRESULT(*d_write)(BYTE drive, const BYTE *buf, DWORD sector, UINT num), DRESULT(*d_ioctl)(BYTE drive, BYTE cmd, void *buf))