+static int loongson_dwmac_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	struct plat_stmmacenet_data *plat;
+	struct stmmac_resources res;
+	int ret, i, mdio;
+	struct device_node *np;
+
+	np = dev_of_node(&pdev->dev);
+
+	if (!np) {
+		pr_info("dwmac_loongson_pci: No OF node\n");
+		return -ENODEV;
+	}
+
+	if (!of_device_is_compatible(np, "loongson, pci-gmac")) {
+		pr_info("dwmac_loongson_pci: Incompatible OF node\n");
+		return -ENODEV;
+	}
+
+	plat = devm_kzalloc(&pdev->dev, sizeof(*plat), GFP_KERNEL);
+	if (!plat)
+		return -ENOMEM;
+
+	if (plat->mdio_node) {
+		dev_err(&pdev->dev, "Found MDIO subnode\n");

It is an error is an MDIO node is found?

+		mdio = true;
+	}
+

...

+
+	plat->phy_interface = device_get_phy_mode(&pdev->dev);
+	if (plat->phy_interface < 0)
+		dev_err(&pdev->dev, "phy_mode not found\n");
+
+	plat->interface = PHY_INTERFACE_MODE_GMII;

Seems odd you call device_get_phy_mode() but then have this hard coded
PHY_INTERFACE_MODE_GMII?

	Andrew