RL_RXCFG
CSR_WRITE_4(sc, RL_RXCFG, RL_RXCFG_CONFIG);
rxfilt = CSR_READ_4(sc, RL_RXCFG);
CSR_WRITE_4(sc, RL_RXCFG, rxfilt);
CSR_WRITE_4(sc, RL_RXCFG, CSR_READ_4(sc, RL_RXCFG) &
CSR_WRITE_4(sc, RL_RXCFG, rxfilt);