GM_RX_CTRL
GMAC_WRITE_2(sc, sc_if->msk_port, GM_RX_CTRL, GM_RXCR_CRC_DIS);
mode = GMAC_READ_2(sc, sc_if->msk_port, GM_RX_CTRL);
GMAC_WRITE_2(sc, sc_if->msk_port, GM_RX_CTRL, mode);