def get_iface_tx_type(block: IpBlock,
                      iface_name: Optional[str],
                      hw2reg: bool) -> str:
    x2x = 'hw2reg' if hw2reg else 'reg2hw'
    pfx = get_type_name_pfx(block, iface_name)
    return '_'.join([pfx, x2x, 't'])