DMAC_NO_CHANNEL
dxs->dxs_channel = DMAC_NO_CHANNEL;
dxs->dxs_channel = DMAC_NO_CHANNEL;
KASSERT(dxs->dxs_channel != (uint8_t)DMAC_NO_CHANNEL);
dxs->dxs_channel = DMAC_NO_CHANNEL;
dxs->dxs_channel = DMAC_NO_CHANNEL;
if (dxs->dxs_channel == DMAC_NO_CHANNEL) {