PAS_DMA_TXCHAN_INCR
write_dma_reg(PAS_DMA_TXCHAN_INCR(csring->chan.chno), (cs_size) >> 1);
write_dma_reg(PAS_DMA_TXCHAN_INCR(txring->chan.chno), 2);
write_dma_reg(PAS_DMA_TXCHAN_INCR(txring->chan.chno), (nfrags+2) >> 1);