RTK_MII
CSR_WRITE_1(sc, RTK_MII, \
CSR_READ_1(sc, RTK_MII) | (x))
CSR_WRITE_1(sc, RTK_MII, \
CSR_READ_1(sc, RTK_MII) & ~(x))
CSR_WRITE_2(sc, RTK_MII, 0);
ack = CSR_READ_2(sc, RTK_MII) & RTK_MII_DATAIN;
if (CSR_READ_2(sc, RTK_MII) & RTK_MII_DATAIN)