octeontx2-pf: Configure VF mtu via representor

Adds support to manage the mtu configuration for VF through representor.
On update of representor mtu a mbox notification is send
to VF to update its mtu.

This feature is implemented based on the "Network Function Representors"
kernel documentation.
"
Setting an MTU on the representor should cause that same MTU
to be reported to the representee.
"

Signed-off-by: Sai Krishna <saikrishnag@marvell.com>
Signed-off-by: Geetha sowjanya <gakula@marvell.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c

@@ -854,6 +854,11 @@ static int otx2_mbox_up_handler_rep_event_up_notify(struct otx2_nic *pf,
 {
 	struct net_device *netdev = pf->netdev;
 
+	if (info->event == RVU_EVENT_MTU_CHANGE) {
+		netdev->mtu = info->evt_data.mtu;
+		return 0;
+	}
+
 	if (info->event == RVU_EVENT_PORT_STATE) {
 		if (info->evt_data.port_state) {
 			pf->flags |= OTX2_FLAG_PORT_UP;

drivers/net/ethernet/marvell/octeontx2/nic/rep.c

@@ -79,6 +79,22 @@ int rvu_event_up_notify(struct otx2_nic *pf, struct rep_event *info)
 	return 0;
 }
 
+static int rvu_rep_change_mtu(struct net_device *dev, int new_mtu)
+{
+	struct rep_dev *rep = netdev_priv(dev);
+	struct otx2_nic *priv = rep->mdev;
+	struct rep_event evt = {0};
+
+	netdev_info(dev, "Changing MTU from %d to %d\n",
+		    dev->mtu, new_mtu);
+	dev->mtu = new_mtu;
+
+	evt.evt_data.mtu = new_mtu;
+	evt.pcifunc = rep->pcifunc;
+	rvu_rep_notify_pfvf(priv, RVU_EVENT_MTU_CHANGE, &evt);
+	return 0;
+}
+
 static void rvu_rep_get_stats(struct work_struct *work)
 {
 	struct delayed_work *del_work = to_delayed_work(work);
@@ -226,6 +242,7 @@ static const struct net_device_ops rvu_rep_netdev_ops = {
 	.ndo_stop		= rvu_rep_stop,
 	.ndo_start_xmit		= rvu_rep_xmit,
 	.ndo_get_stats64	= rvu_rep_get_stats64,
+	.ndo_change_mtu		= rvu_rep_change_mtu,
 };
 
 static int rvu_rep_napi_init(struct otx2_nic *priv,