T1_TBS_MASK
txd->xd1 = htole32(T1_FS | T1_LS | T1_TCH | (len & T1_TBS_MASK));
txd->xd1 = htole32(T1_FS | T1_LS | (len & T1_TBS_MASK));
txd->xd1 |= htole32(T1_FS | T1_LS | (len & T1_TBS_MASK));
| (dmamap->dm_segs[seg].ds_len & T1_TBS_MASK);