From: Magnus Damm <damm+rene...@opensource.se>
Allow adjusting the MTU for via-rhine devices in case of no TX alignment
buffer is used.
Lightly tested on ALIX2D13 hardware by making use of VXLAN with MTU set
to 1500 on top of via-rhine devices with 1550 MTU. Without this patch
the VXLAN MTU is limited to less than 1500.
Signed-off-by: Magnus Damm <damm+rene...@opensource.se>
---
Developed on top of next-20170613
drivers/net/ethernet/via/via-rhine.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
--- 0001/drivers/net/ethernet/via/via-rhine.c
+++ work/drivers/net/ethernet/via/via-rhine.c 2017-06-14 02:05:25.410607110
+0900
@@ -518,6 +518,7 @@ static void rhine_get_stats64(struct net
static int netdev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
static const struct ethtool_ops netdev_ethtool_ops;
static int rhine_close(struct net_device *dev);
+static int rhine_change_mtu(struct net_device *dev, int new_mtu);
static int rhine_vlan_rx_add_vid(struct net_device *dev,
__be16 proto, u16 vid);
static int rhine_vlan_rx_kill_vid(struct net_device *dev,
@@ -894,6 +895,7 @@ static const struct net_device_ops rhine
.ndo_set_mac_address = eth_mac_addr,
.ndo_do_ioctl = netdev_ioctl,
.ndo_tx_timeout = rhine_tx_timeout,
+ .ndo_change_mtu = rhine_change_mtu,
.ndo_vlan_rx_add_vid = rhine_vlan_rx_add_vid,
.ndo_vlan_rx_kill_vid = rhine_vlan_rx_kill_vid,
#ifdef CONFIG_NET_POLL_CONTROLLER
@@ -981,6 +983,14 @@ static int rhine_init_one_common(struct
NETIF_F_HW_VLAN_CTAG_RX |
NETIF_F_HW_VLAN_CTAG_FILTER;
+ /* Allow MTU configuration as long as TX alignment buffer is unused */
+ if (!(rp->quirks & rqRhineI)) {
+ /* Packets less than 64 octets will raise RDES0.RUNT. */
+ dev->min_mtu = ETH_ZLEN - ETH_HLEN;
+ /* Hardware has 11 bits of RDES0.Rx_Length including FCS. */
+ dev->max_mtu = 0x1fff - ETH_HLEN - ETH_FCS_LEN;
+ }
+
/* dev->name not defined before register_netdev()! */
rc = register_netdev(dev);
if (rc)
@@ -1399,6 +1409,15 @@ static void rhine_set_carrier(struct mii
mii->force_media, netif_carrier_ok(dev));
}
+static int rhine_change_mtu(struct net_device *dev, int new_mtu)
+{
+ if (dev->flags & IFF_UP)
+ return -EBUSY;
+
+ dev->mtu = new_mtu;
+ return 0;
+}
+
/**
* rhine_set_cam - set CAM multicast filters
* @ioaddr: register block of this Rhine
