XFER_START
writel(xfer_ctr | xfer_cnt | XFER_START,
writel(readl(acdev->vbase + XFER_CTR) & ~XFER_START,
writel(readl(acdev->vbase + XFER_CTR) & ~XFER_START,
writel(readl(acdev->vbase + XFER_CTR) & ~XFER_START,