RE_TIMERINT
CSR_WRITE_4(sc, RE_TIMERINT, 0);
CSR_READ_4(sc, RE_TIMERINT); /* flush */
CSR_WRITE_4(sc, RE_TIMERINT, ticks);
CSR_WRITE_4(sc, RE_TIMERINT, 0);
CSR_WRITE_4(sc, RE_TIMERINT, 0x4000);