TL_CMD_RT
r |= (TL_CMD_GO|TL_CMD_RT);
cmd &= ~TL_CMD_RT;
cmd &= ~TL_CMD_RT;
CMD_SET(sc, TL_CMD_RT);
CMD_SET(sc, TL_CMD_GO|TL_CMD_NES|TL_CMD_RT);
CMD_CLR(sc, TL_CMD_RT);
CMD_SET(sc, TL_CMD_RT);
cmd &= ~(TL_CMD_RT|TL_CMD_EOC|TL_CMD_ACK_MASK|TL_CMD_CHSEL_MASK);