net: mvneta: disable IP checksum with jumbo frames for Armada 370

The Ethernet controller found in the Armada 370, 380 and 385 SoCs don't
support TCP/IP checksumming with frame sizes larger than 1600 bytes.

This patch fixes the issue by disabling the features NETIF_F_IP_CSUM and
NETIF_F_TSO for the Armada 370 and compatibles SoCs when the MTU is set
to a value greater than 1600 bytes.

Signed-off-by: Simon Guinot <simon.guinot@sequanux.org>
Fixes: c5aff18204da ("net: mvneta: driver for Marvell Armada 370/XP network unit")
Cc: <stable@vger.kernel.org> # v3.8+
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 218749c..370e20e 100644 (file)
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -310,6 +310,7 @@ struct mvneta_port {
        unsigned int link;
        unsigned int duplex;
        unsigned int speed;
+       unsigned int tx_csum_limit;
        int use_inband_status:1;
 };
 
@@ -2508,8 +2509,10 @@ static int mvneta_change_mtu(struct net_device *dev, int mtu)
 
        dev->mtu = mtu;
 
-       if (!netif_running(dev))
+       if (!netif_running(dev)) {
+               netdev_update_features(dev);
                return 0;
+       }
 
        /* The interface is running, so we have to force a
         * reallocation of the queues
@@ -2538,9 +2541,26 @@ static int mvneta_change_mtu(struct net_device *dev, int mtu)
        mvneta_start_dev(pp);
        mvneta_port_up(pp);
 
+       netdev_update_features(dev);
+
        return 0;
 }
 
+static netdev_features_t mvneta_fix_features(struct net_device *dev,
+                                            netdev_features_t features)
+{
+       struct mvneta_port *pp = netdev_priv(dev);
+
+       if (pp->tx_csum_limit && dev->mtu > pp->tx_csum_limit) {
+               features &= ~(NETIF_F_IP_CSUM | NETIF_F_TSO);
+               netdev_info(dev,
+                           "Disable IP checksum for MTU greater than %dB\n",
+                           pp->tx_csum_limit);
+       }
+
+       return features;
+}
+
 /* Get mac address */
 static void mvneta_get_mac_addr(struct mvneta_port *pp, unsigned char *addr)
 {
@@ -2862,6 +2882,7 @@ static const struct net_device_ops mvneta_netdev_ops = {
        .ndo_set_rx_mode     = mvneta_set_rx_mode,
        .ndo_set_mac_address = mvneta_set_mac_addr,
        .ndo_change_mtu      = mvneta_change_mtu,
+       .ndo_fix_features    = mvneta_fix_features,
        .ndo_get_stats64     = mvneta_get_stats64,
        .ndo_do_ioctl        = mvneta_ioctl,
 };
@@ -3107,6 +3128,9 @@ static int mvneta_probe(struct platform_device *pdev)
                }
        }
 
+       if (of_device_is_compatible(dn, "marvell,armada-370-neta"))
+               pp->tx_csum_limit = 1600;
+
        pp->tx_ring_size = MVNETA_MAX_TXD;
        pp->rx_ring_size = MVNETA_MAX_RXD;