SIS_RXFILTCTL_ENABLE
SIS_SETBIT(sc, SIS_RXFILT_CTL, SIS_RXFILTCTL_ENABLE);
CSR_WRITE_4(sc, SIS_RXFILT_CTL, filtsave & ~SIS_RXFILTCTL_ENABLE);
ctl = CSR_READ_4(sc, SIS_RXFILT_CTL) & SIS_RXFILTCTL_ENABLE;