RXDP
writel(virt_to_le32desc(&rx_ring[ns->cur_rx]), ns->base + RXDP); \
writel(virt_to_le32desc(&rx_ring[0]), ns->base + RXDP);
writel(0, ns->base + RXDP);
OUTL(dp, RXDP, dp->rx_ring_dma +
OUTL(dp, RXDP, dp->rx_ring_dma);