PCIIDE_DMACTL_READ
status = PCIIDE_DMACTL_READ(sc, chan);
PCIIDE_DMACTL_WRITE(sc, channel, PCIIDE_DMACTL_READ(sc, channel));
status = PCIIDE_DMACTL_READ(sc, channel);
PCIIDE_DMACTL_WRITE(sc, chan, PCIIDE_DMACTL_READ(sc, chan));