net: lan966x: Introduce helper functions

Introduce lan966x_fdma_tx_setup_dcb and lan966x_fdma_tx_start functions
and use of them inside lan966x_fdma_xmit. There is no functional change
in here.
They are introduced to be used when XDP_TX/REDIRECT actions are
introduced.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c

@@ -612,14 +612,53 @@ static int lan966x_fdma_get_next_dcb(struct lan966x_tx *tx)
 	return -1;
 }
 
+static void lan966x_fdma_tx_setup_dcb(struct lan966x_tx *tx,
+				      int next_to_use, int len,
+				      dma_addr_t dma_addr)
+{
+	struct lan966x_tx_dcb *next_dcb;
+	struct lan966x_db *next_db;
+
+	next_dcb = &tx->dcbs[next_to_use];
+	next_dcb->nextptr = FDMA_DCB_INVALID_DATA;
+
+	next_db = &next_dcb->db[0];
+	next_db->dataptr = dma_addr;
+	next_db->status = FDMA_DCB_STATUS_SOF |
+			  FDMA_DCB_STATUS_EOF |
+			  FDMA_DCB_STATUS_INTR |
+			  FDMA_DCB_STATUS_BLOCKO(0) |
+			  FDMA_DCB_STATUS_BLOCKL(len);
+}
+
+static void lan966x_fdma_tx_start(struct lan966x_tx *tx, int next_to_use)
+{
+	struct lan966x *lan966x = tx->lan966x;
+	struct lan966x_tx_dcb *dcb;
+
+	if (likely(lan966x->tx.activated)) {
+		/* Connect current dcb to the next db */
+		dcb = &tx->dcbs[tx->last_in_use];
+		dcb->nextptr = tx->dma + (next_to_use *
+					  sizeof(struct lan966x_tx_dcb));
+
+		lan966x_fdma_tx_reload(tx);
+	} else {
+		/* Because it is first time, then just activate */
+		lan966x->tx.activated = true;
+		lan966x_fdma_tx_activate(tx);
+	}
+
+	/* Move to next dcb because this last in use */
+	tx->last_in_use = next_to_use;
+}
+
 int lan966x_fdma_xmit(struct sk_buff *skb, __be32 *ifh, struct net_device *dev)
 {
 	struct lan966x_port *port = netdev_priv(dev);
 	struct lan966x *lan966x = port->lan966x;
 	struct lan966x_tx_dcb_buf *next_dcb_buf;
-	struct lan966x_tx_dcb *next_dcb, *dcb;
 	struct lan966x_tx *tx = &lan966x->tx;
-	struct lan966x_db *next_db;
 	int needed_headroom;
 	int needed_tailroom;
 	dma_addr_t dma_addr;
@@ -665,16 +704,7 @@ int lan966x_fdma_xmit(struct sk_buff *skb, __be32 *ifh, struct net_device *dev)
 	}
 
 	/* Setup next dcb */
-	next_dcb = &tx->dcbs[next_to_use];
-	next_dcb->nextptr = FDMA_DCB_INVALID_DATA;
-
-	next_db = &next_dcb->db[0];
-	next_db->dataptr = dma_addr;
-	next_db->status = FDMA_DCB_STATUS_SOF |
-			  FDMA_DCB_STATUS_EOF |
-			  FDMA_DCB_STATUS_INTR |
-			  FDMA_DCB_STATUS_BLOCKO(0) |
-			  FDMA_DCB_STATUS_BLOCKL(skb->len);
+	lan966x_fdma_tx_setup_dcb(tx, next_to_use, skb->len, dma_addr);
 
 	/* Fill up the buffer */
 	next_dcb_buf = &tx->dcbs_buf[next_to_use];
@@ -688,21 +718,8 @@ int lan966x_fdma_xmit(struct sk_buff *skb, __be32 *ifh, struct net_device *dev)
 	    LAN966X_SKB_CB(skb)->rew_op == IFH_REW_OP_TWO_STEP_PTP)
 		next_dcb_buf->ptp = true;
 
-	if (likely(lan966x->tx.activated)) {
-		/* Connect current dcb to the next db */
-		dcb = &tx->dcbs[tx->last_in_use];
-		dcb->nextptr = tx->dma + (next_to_use *
-					  sizeof(struct lan966x_tx_dcb));
-
-		lan966x_fdma_tx_reload(tx);
-	} else {
-		/* Because it is first time, then just activate */
-		lan966x->tx.activated = true;
-		lan966x_fdma_tx_activate(tx);
-	}
-
-	/* Move to next dcb because this last in use */
-	tx->last_in_use = next_to_use;
+	/* Start the transmission */
+	lan966x_fdma_tx_start(tx, next_to_use);
 
 	return NETDEV_TX_OK;