[RFC/PATCH 14/18] ravb: Add rx_ring_format function for GbEthernet

[Biju Das <biju.das.jz@xxxxxxxxxxxxxx>]

This patch adds rx_ring_format function for GbEthernet found on
RZ/G2L SoC.

Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
---
 drivers/net/ethernet/renesas/ravb.h      |  1 +
 drivers/net/ethernet/renesas/ravb_main.c | 27 +++++++++++++++++++++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h
index 2505de5d4a28..b0e067a6a8ee 100644
--- a/drivers/net/ethernet/renesas/ravb.h
+++ b/drivers/net/ethernet/renesas/ravb.h
@@ -982,6 +982,7 @@ enum CSR0_BIT {
 #define RX_BUF_SZ	(2048 - ETH_FCS_LEN + sizeof(__sum16))
 
 #define RGETH_RX_BUFF_MAX 8192
+#define RGETH_RX_DESC_DATA_SIZE 4080
 
 struct ravb_tstamp_skb {
 	struct list_head list;
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 038af36141bb..ee1066fedc4a 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -327,7 +327,32 @@ static void ravb_ring_free(struct net_device *ndev, int q)
 
 static void ravb_rx_ring_format_rgeth(struct net_device *ndev, int q)
 {
-	/* Place holder */
+	struct ravb_private *priv = netdev_priv(ndev);
+	struct ravb_rx_desc *rx_desc;
+	unsigned int rx_ring_size = sizeof(*rx_desc) * priv->num_rx_ring[q];
+	dma_addr_t dma_addr;
+	unsigned int i;
+
+	memset(priv->rgeth_rx_ring[q], 0, rx_ring_size);
+	/* Build RX ring buffer */
+	for (i = 0; i < priv->num_rx_ring[q]; i++) {
+		/* RX descriptor */
+		rx_desc = &priv->rgeth_rx_ring[q][i];
+		rx_desc->ds_cc = cpu_to_le16(RGETH_RX_DESC_DATA_SIZE);
+		dma_addr = dma_map_single(ndev->dev.parent, priv->rx_skb[q][i]->data,
+					  RGETH_RX_BUFF_MAX,
+					  DMA_FROM_DEVICE);
+		/* We just set the data size to 0 for a failed mapping which
+		 * should prevent DMA from happening...
+		 */
+		if (dma_mapping_error(ndev->dev.parent, dma_addr))
+			rx_desc->ds_cc = cpu_to_le16(0);
+		rx_desc->dptr = cpu_to_le32(dma_addr);
+		rx_desc->die_dt = DT_FEMPTY;
+	}
+	rx_desc = &priv->rgeth_rx_ring[q][i];
+	rx_desc->dptr = cpu_to_le32((u32)priv->rx_desc_dma[q]);
+	rx_desc->die_dt = DT_LINKFIX; /* type */
 }
 
 static void ravb_rx_ring_format(struct net_device *ndev, int q)
-- 
2.17.1