BCM_DMA_CH_FREE
ch->flags = BCM_DMA_CH_FREE;
if (sc->sc_dma_ch[i].flags & BCM_DMA_CH_FREE) {
sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
} else if (sc->sc_dma_ch[req_ch].flags & BCM_DMA_CH_FREE) {
sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_FREE;