act_trcnt
cs->act_trcnt = scb->sc_ctrnscnt;
cs->act_trcnt = scb->sc_ctrnscnt;
scb->sc_ctrnscnt = cs->act_trcnt;
if (cs->act_trcnt <= 0) {
i = (cs->act_trcnt + DEV_BSIZE -1) / DEV_BSIZE;
i = cs->act_trcnt;
sc->pad_cnt[cs->chan_num] = i - cs->act_trcnt;
dmac_ctrcl = (uint8_t)(cs->act_trcnt & 0xff);
dmac_ctrcm = (uint8_t)((cs->act_trcnt >> 8) & 0xff);
dmac_ctrch = (uint8_t)((cs->act_trcnt >> 16) & 0x0f);
pages = (cs->act_trcnt >> PGSHIFT) + 2;
if (cs->act_trcnt >= 0)
cs->act_trcnt = remain_cnt;