net/macb: change RX path for GEM

GEM is able to adapt its DMA buffer size, so change
the RX path to take advantage of this possibility and
remove all kind of memcpy in this path.
This modification introduces function pointers for managing
differences between MACB and GEM adapter type.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cadence/macb.h

@@ -545,11 +545,22 @@ struct gem_stats {
 	u32	rx_udp_checksum_errors;
 };
 
+struct macb;
+
+struct macb_or_gem_ops {
+	int	(*mog_alloc_rx_buffers)(struct macb *bp);
+	void	(*mog_free_rx_buffers)(struct macb *bp);
+	void	(*mog_init_rings)(struct macb *bp);
+	int	(*mog_rx)(struct macb *bp, int budget);
+};
+
 struct macb {
 	void __iomem		*regs;
 
 	unsigned int		rx_tail;
+	unsigned int		rx_prepared_head;
 	struct macb_dma_desc	*rx_ring;
+	struct sk_buff		**rx_skbuff;
 	void			*rx_buffers;
 	size_t			rx_buffer_size;
 
@@ -574,6 +585,8 @@ struct macb {
 	dma_addr_t		tx_ring_dma;
 	dma_addr_t		rx_buffers_dma;
 
+	struct macb_or_gem_ops	macbgem_ops;
+
 	struct mii_bus		*mii_bus;
 	struct phy_device	*phy_dev;
 	unsigned int 		link;