STMMAC_RING_MODE
priv->mode = STMMAC_RING_MODE;
STMMAC_RING_MODE, 0, false, skb->len);
STMMAC_RING_MODE, 1, !skb_is_nonlinear(skb),
STMMAC_RING_MODE, 0, !skb_is_nonlinear(skb),
if (priv->extend_desc && (priv->mode == STMMAC_RING_MODE))