net/mlx5e: ethtool, Fix restriction of autoneg with 56G

Prior to this patch, configuring speed to 50G with autoneg off over
devices supporting 50G per lane failed.
Support for 50G per lane introduced a new set of link-modes, on which
driver always performed a speed validation as if only legacy link-modes
were configured. Fix driver speed validation to force setting autoneg
over 56G only if in legacy link-mode.

Fixes: 3d7cadae ("net/mlx5e: ethtool, Fix analysis of speed setting")
Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Eran Ben Elisha <eranbe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c

@@ -1010,6 +1010,22 @@ static int mlx5e_get_link_ksettings(struct net_device *netdev,
 	return mlx5e_ethtool_get_link_ksettings(priv, link_ksettings);
 }
 
+static int mlx5e_speed_validate(struct net_device *netdev, bool ext,
+				const unsigned long link_modes, u8 autoneg)
+{
+	/* Extended link-mode has no speed limitations. */
+	if (ext)
+		return 0;
+
+	if ((link_modes & MLX5E_PROT_MASK(MLX5E_56GBASE_R4)) &&
+	    autoneg != AUTONEG_ENABLE) {
+		netdev_err(netdev, "%s: 56G link speed requires autoneg enabled\n",
+			   __func__);
+		return -EINVAL;
+	}
+	return 0;
+}
+
 static u32 mlx5e_ethtool2ptys_adver_link(const unsigned long *link_modes)
 {
 	u32 i, ptys_modes = 0;
@@ -1103,13 +1119,9 @@ int mlx5e_ethtool_set_link_ksettings(struct mlx5e_priv *priv,
 	link_modes = autoneg == AUTONEG_ENABLE ? ethtool2ptys_adver_func(adver) :
 		mlx5e_port_speed2linkmodes(mdev, speed, !ext);
 
-	if ((link_modes & MLX5E_PROT_MASK(MLX5E_56GBASE_R4)) &&
-	    autoneg != AUTONEG_ENABLE) {
-		netdev_err(priv->netdev, "%s: 56G link speed requires autoneg enabled\n",
-			   __func__);
-		err = -EINVAL;
+	err = mlx5e_speed_validate(priv->netdev, ext, link_modes, autoneg);
+	if (err)
 		goto out;
-	}
 
 	link_modes = link_modes & eproto.cap;
 	if (!link_modes) {