ravb: Factorise ravb_ring_init function

The ravb_ring_init function uses an extended descriptor in RX for
R-Car and normal descriptor for RZ/G2L. Add a helper function
for RX ring buffer allocation to support later SoC.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/renesas/ravb.h

@@ -982,6 +982,7 @@ struct ravb_ptp {
 struct ravb_hw_info {
 	void (*rx_ring_free)(struct net_device *ndev, int q);
 	void (*rx_ring_format)(struct net_device *ndev, int q);
+	void *(*alloc_rx_desc)(struct net_device *ndev, int q);
 	const char (*gstrings_stats)[ETH_GSTRING_LEN];
 	size_t gstrings_size;
 	netdev_features_t net_hw_features;

drivers/net/ethernet/renesas/ravb_main.c

@@ -355,6 +355,19 @@ static void ravb_ring_format(struct net_device *ndev, int q)
 	desc->dptr = cpu_to_le32((u32)priv->tx_desc_dma[q]);
 }
 
+static void *ravb_alloc_rx_desc(struct net_device *ndev, int q)
+{
+	struct ravb_private *priv = netdev_priv(ndev);
+	unsigned int ring_size;
+
+	ring_size = sizeof(struct ravb_ex_rx_desc) * (priv->num_rx_ring[q] + 1);
+
+	priv->rx_ring[q] = dma_alloc_coherent(ndev->dev.parent, ring_size,
+					      &priv->rx_desc_dma[q],
+					      GFP_KERNEL);
+	return priv->rx_ring[q];
+}
+
 /* Init skb and descriptor buffer for Ethernet AVB */
 static int ravb_ring_init(struct net_device *ndev, int q)
 {
@@ -390,11 +403,7 @@ static int ravb_ring_init(struct net_device *ndev, int q)
 	}
 
 	/* Allocate all RX descriptors. */
-	ring_size = sizeof(struct ravb_ex_rx_desc) * (priv->num_rx_ring[q] + 1);
-	priv->rx_ring[q] = dma_alloc_coherent(ndev->dev.parent, ring_size,
-					      &priv->rx_desc_dma[q],
-					      GFP_KERNEL);
-	if (!priv->rx_ring[q])
+	if (!info->alloc_rx_desc(ndev, q))
 		goto error;
 
 	priv->dirty_rx[q] = 0;
@@ -1959,6 +1968,7 @@ static int ravb_mdio_release(struct ravb_private *priv)
 static const struct ravb_hw_info ravb_gen3_hw_info = {
 	.rx_ring_free = ravb_rx_ring_free,
 	.rx_ring_format = ravb_rx_ring_format,
+	.alloc_rx_desc = ravb_alloc_rx_desc,
 	.gstrings_stats = ravb_gstrings_stats,
 	.gstrings_size = sizeof(ravb_gstrings_stats),
 	.net_hw_features = NETIF_F_RXCSUM,
@@ -1974,6 +1984,7 @@ static const struct ravb_hw_info ravb_gen3_hw_info = {
 static const struct ravb_hw_info ravb_gen2_hw_info = {
 	.rx_ring_free = ravb_rx_ring_free,
 	.rx_ring_format = ravb_rx_ring_format,
+	.alloc_rx_desc = ravb_alloc_rx_desc,
 	.gstrings_stats = ravb_gstrings_stats,
 	.gstrings_size = sizeof(ravb_gstrings_stats),
 	.net_hw_features = NETIF_F_RXCSUM,