HW_APBHX_CHn_SEMA
writel(2, mxs_dma->base + HW_APBHX_CHn_SEMA(mxs_dma, chan_id));
writel(1, mxs_dma->base + HW_APBHX_CHn_SEMA(mxs_dma, chan_id));
HW_APBHX_CHn_SEMA(mxs_dma, chan));