DMA_MODE_SET
__raw_writel(DMA_BE0, chan->io + DMA_MODE_SET);
__raw_writel(DMA_BE1, chan->io + DMA_MODE_SET);
__raw_writel(DMA_BE0 | DMA_BE1, chan->io + DMA_MODE_SET);
__raw_writel(DMA_GO, chan->io + DMA_MODE_SET);
__raw_writel(mode, chan->io + DMA_MODE_SET);
#define DMA_MODE_READ DMA_MODE_SET