net/mlx5e: Add DCBX control interface

Use setdcbx interface to set the DCBX mode to firmware or os.
If setdcbx is called with mode value of zero, the DCBX mode
is set to firmware.
Signed-off-by: Huy Nguyen <huyn@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -287,13 +287,34 @@ static int mlx5e_dcbnl_ieee_setpfc(struct net_device *dev,
 
 static u8 mlx5e_dcbnl_getdcbx(struct net_device *dev)
 {
-	return DCB_CAP_DCBX_HOST |
-	       DCB_CAP_DCBX_VER_IEEE |
-	       DCB_CAP_DCBX_VER_CEE;
+	struct mlx5e_priv *priv = netdev_priv(dev);
+	struct mlx5e_dcbx *dcbx = &priv->dcbx;
+	u8 mode = DCB_CAP_DCBX_VER_IEEE | DCB_CAP_DCBX_VER_CEE;
+
+	if (dcbx->mode == MLX5E_DCBX_PARAM_VER_OPER_HOST)
+		mode |= DCB_CAP_DCBX_HOST;
+
+	return mode;
 }
 
 static u8 mlx5e_dcbnl_setdcbx(struct net_device *dev, u8 mode)
 {
+	struct mlx5e_priv *priv = netdev_priv(dev);
+	struct mlx5e_dcbx *dcbx = &priv->dcbx;
+
+	if ((!mode) && MLX5_CAP_GEN(priv->mdev, dcbx)) {
+		if (dcbx->mode == MLX5E_DCBX_PARAM_VER_OPER_AUTO)
+			return 0;
+
+		/* set dcbx to fw controlled */
+		if (!mlx5e_dcbnl_set_dcbx_mode(priv, MLX5E_DCBX_PARAM_VER_OPER_AUTO)) {
+			dcbx->mode = MLX5E_DCBX_PARAM_VER_OPER_AUTO;
+			return 0;
+		}
+
+		return 1;
+	}
+
 	if (mlx5e_dcbnl_switch_to_host_mode(netdev_priv(dev)))
 		return 1;