[PATCH net-next v2] ibmveth: Allow users to update reported speed and duplex

[Thomas Falcon <tlfalcon@linux.ibm.com>]

Reported ethtool link settings for the ibmveth driver are currently
hardcoded and no longer reflect the actual capabilities of supported
hardware. There is no interface designed for retrieving this information
from device firmware nor is there any way to update current settings
to reflect observed or expected link speeds.

To avoid breaking existing configurations, retain current values as
default settings but let users update them to match the expected
capabilities of underlying hardware if needed. This update would
allow the use of configurations that rely on certain link speed
settings, such as LACP. This patch is based on the implementation
in virtio_net.

Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
---
v2: Updated default driver speed/duplex settings to avoid
    breaking existing setups
---
 drivers/net/ethernet/ibm/ibmveth.c | 83 ++++++++++++++++++++++++++++----------
 drivers/net/ethernet/ibm/ibmveth.h |  3 ++
 2 files changed, 64 insertions(+), 22 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index d654c23..5dc634f 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -712,31 +712,68 @@ static int ibmveth_close(struct net_device *netdev)
 	return 0;
 }
 
-static int netdev_get_link_ksettings(struct net_device *dev,
-				     struct ethtool_link_ksettings *cmd)
+static bool
+ibmveth_validate_ethtool_cmd(const struct ethtool_link_ksettings *cmd)
 {
-	u32 supported, advertising;
-
-	supported = (SUPPORTED_1000baseT_Full | SUPPORTED_Autoneg |
-				SUPPORTED_FIBRE);
-	advertising = (ADVERTISED_1000baseT_Full | ADVERTISED_Autoneg |
-				ADVERTISED_FIBRE);
-	cmd->base.speed = SPEED_1000;
-	cmd->base.duplex = DUPLEX_FULL;
-	cmd->base.port = PORT_FIBRE;
-	cmd->base.phy_address = 0;
-	cmd->base.autoneg = AUTONEG_ENABLE;
-
-	ethtool_convert_legacy_u32_to_link_mode(cmd->link_modes.supported,
-						supported);
-	ethtool_convert_legacy_u32_to_link_mode(cmd->link_modes.advertising,
-						advertising);
+	struct ethtool_link_ksettings diff1 = *cmd;
+	struct ethtool_link_ksettings diff2 = {};
+
+	diff2.base.port = PORT_OTHER;
+	diff1.base.speed = 0;
+	diff1.base.duplex = 0;
+	diff1.base.cmd = 0;
+	diff1.base.link_mode_masks_nwords = 0;
+	ethtool_link_ksettings_zero_link_mode(&diff1, advertising);
+
+	return !memcmp(&diff1.base, &diff2.base, sizeof(diff1.base)) &&
+		bitmap_empty(diff1.link_modes.supported,
+			     __ETHTOOL_LINK_MODE_MASK_NBITS) &&
+		bitmap_empty(diff1.link_modes.advertising,
+			     __ETHTOOL_LINK_MODE_MASK_NBITS) &&
+		bitmap_empty(diff1.link_modes.lp_advertising,
+			     __ETHTOOL_LINK_MODE_MASK_NBITS);
+}
+
+static int ibmveth_set_link_ksettings(struct net_device *dev,
+				      const struct ethtool_link_ksettings *cmd)
+{
+	struct ibmveth_adapter *adapter = netdev_priv(dev);
+	u32 speed;
+	u8 duplex;
+
+	speed = cmd->base.speed;
+	duplex = cmd->base.duplex;
+	/* don't allow custom speed and duplex */
+	if (!ethtool_validate_speed(speed) ||
+	    !ethtool_validate_duplex(duplex) ||
+	    !ibmveth_validate_ethtool_cmd(cmd))
+		return -EINVAL;
+	adapter->speed = speed;
+	adapter->duplex = duplex;
 
 	return 0;
 }
 
-static void netdev_get_drvinfo(struct net_device *dev,
-			       struct ethtool_drvinfo *info)
+static int ibmveth_get_link_ksettings(struct net_device *dev,
+				      struct ethtool_link_ksettings *cmd)
+{
+	struct ibmveth_adapter *adapter = netdev_priv(dev);
+
+	cmd->base.speed = adapter->speed;
+	cmd->base.duplex = adapter->duplex;
+	cmd->base.port = PORT_OTHER;
+
+	return 0;
+}
+
+static void ibmveth_init_link_settings(struct ibmveth_adapter *adapter)
+{
+	adapter->duplex = DUPLEX_FULL;
+	adapter->speed = SPEED_1000;
+}
+
+static void ibmveth_get_drvinfo(struct net_device *dev,
+				struct ethtool_drvinfo *info)
 {
 	strlcpy(info->driver, ibmveth_driver_name, sizeof(info->driver));
 	strlcpy(info->version, ibmveth_driver_version, sizeof(info->version));
@@ -965,12 +1002,13 @@ static void ibmveth_get_ethtool_stats(struct net_device *dev,
 }
 
 static const struct ethtool_ops netdev_ethtool_ops = {
-	.get_drvinfo		= netdev_get_drvinfo,
+	.get_drvinfo		= ibmveth_get_drvinfo,
 	.get_link		= ethtool_op_get_link,
 	.get_strings		= ibmveth_get_strings,
 	.get_sset_count		= ibmveth_get_sset_count,
 	.get_ethtool_stats	= ibmveth_get_ethtool_stats,
-	.get_link_ksettings	= netdev_get_link_ksettings,
+	.get_link_ksettings	= ibmveth_get_link_ksettings,
+	.set_link_ksettings	= ibmveth_set_link_ksettings
 };
 
 static int ibmveth_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
@@ -1647,6 +1685,7 @@ static int ibmveth_probe(struct vio_dev *dev, const struct vio_device_id *id)
 	adapter->netdev = netdev;
 	adapter->mcastFilterSize = *mcastFilterSize_p;
 	adapter->pool_config = 0;
+	ibmveth_init_link_settings(adapter);
 
 	netif_napi_add(netdev, &adapter->napi, ibmveth_poll, 16);
 
diff --git a/drivers/net/ethernet/ibm/ibmveth.h b/drivers/net/ethernet/ibm/ibmveth.h
index 4e9bf34..db96c88 100644
--- a/drivers/net/ethernet/ibm/ibmveth.h
+++ b/drivers/net/ethernet/ibm/ibmveth.h
@@ -162,6 +162,9 @@ struct ibmveth_adapter {
     u64 tx_send_failed;
     u64 tx_large_packets;
     u64 rx_large_packets;
+    /* Ethtool settings */
+    u8 duplex;
+    u32 speed;
 };
 
 /*
-- 
1.8.3.1