[PATCH 4/8] net: dsa: allow rcv() and xmit() to be optional

[Tim Harvey <tharvey@gateworks.com>]

Allow rcv() and xmit() dsa driver ops to be optional in case a driver
does not care to mangle a packet as in U-Boot only one network port is
enabled at a time and thus no packet mangling is necessary.

Suggested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
---
v2: new patch
---
 net/dsa-uclass.c | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/net/dsa-uclass.c b/net/dsa-uclass.c
index b3033c97aa63..f82217e0d7a7 100644
--- a/net/dsa-uclass.c
+++ b/net/dsa-uclass.c
@@ -131,16 +131,14 @@ static void dsa_port_stop(struct udevice *pdev)
  * We copy the frame to a stack buffer where we have reserved headroom and
  * tailroom space.  Headroom and tailroom are set to 0.
  */
-static int dsa_port_send(struct udevice *pdev, void *packet, int length)
+static int dsa_port_mangle_packet(struct udevice *pdev, void *packet, int length)
 {
+	struct dsa_port_pdata *port_pdata = dev_get_parent_plat(pdev);
 	struct udevice *dev = dev_get_parent(pdev);
 	struct dsa_priv *priv = dev_get_uclass_priv(dev);
 	int head = priv->headroom, tail = priv->tailroom;
-	struct udevice *master = dsa_get_master(dev);
 	struct dsa_ops *ops = dsa_get_ops(dev);
 	uchar dsa_packet_tmp[PKTSIZE_ALIGN];
-	struct dsa_port_pdata *port_pdata;
-	int err;
 
 	if (length + head + tail > PKTSIZE_ALIGN)
 		return -EINVAL;
@@ -152,10 +150,21 @@ static int dsa_port_send(struct udevice *pdev, void *packet, int length)
 	/* copy back to preserve original buffer alignment */
 	memcpy(packet, dsa_packet_tmp, length);
 
-	port_pdata = dev_get_parent_plat(pdev);
-	err = ops->xmit(dev, port_pdata->index, packet, length);
-	if (err)
-		return err;
+	return ops->xmit(dev, port_pdata->index, packet, length);
+}
+
+static int dsa_port_send(struct udevice *pdev, void *packet, int length)
+{
+	struct udevice *dev = dev_get_parent(pdev);
+	struct udevice *master = dsa_get_master(dev);
+	struct dsa_ops *ops = dsa_get_ops(dev);
+	int err;
+
+	if (ops->xmit) {
+		err = dsa_port_mangle_packet(pdev, packet, length);
+		if (err)
+			return err;
+	}
 
 	return eth_get_ops(master)->send(master, packet, length);
 }
@@ -172,7 +181,7 @@ static int dsa_port_recv(struct udevice *pdev, int flags, uchar **packetp)
 	int length, port_index, err;
 
 	length = eth_get_ops(master)->recv(master, flags, packetp);
-	if (length <= 0)
+	if (length <= 0 || !ops->rcv)
 		return length;
 
 	/*
-- 
2.17.1