net: mvpp2: Defer probe if MAC address source is not yet ready

NVMEM layouts are no longer registered early, and thus may not yet be
available when Ethernet drivers (or any other consumer) probe, leading
to possible probe deferrals errors. Forward the error code if this
happens. All other errors being discarded, the driver will eventually
use a random MAC address if no other source was considered valid (no
functional change on this regard).

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Marcin Wojtas <mw@semihalf.com>
Link: https://lore.kernel.org/r/20230307192927.512757-1-miquel.raynal@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: miquelraynal

drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c

@@ -6081,38 +6081,44 @@ static bool mvpp2_port_has_irqs(struct mvpp2 *priv,
 	return true;
 }
 
-static void mvpp2_port_copy_mac_addr(struct net_device *dev, struct mvpp2 *priv,
-				     struct fwnode_handle *fwnode,
-				     char **mac_from)
+static int mvpp2_port_copy_mac_addr(struct net_device *dev, struct mvpp2 *priv,
+				    struct fwnode_handle *fwnode,
+				    char **mac_from)
 {
 	struct mvpp2_port *port = netdev_priv(dev);
 	char hw_mac_addr[ETH_ALEN] = {0};
 	char fw_mac_addr[ETH_ALEN];
+	int ret;
 
 	if (!fwnode_get_mac_address(fwnode, fw_mac_addr)) {
 		*mac_from = "firmware node";
 		eth_hw_addr_set(dev, fw_mac_addr);
-		return;
+		return 0;
 	}
 
 	if (priv->hw_version == MVPP21) {
 		mvpp21_get_mac_address(port, hw_mac_addr);
 		if (is_valid_ether_addr(hw_mac_addr)) {
 			*mac_from = "hardware";
 			eth_hw_addr_set(dev, hw_mac_addr);
-			return;
+			return 0;
 		}
 	}
 
 	/* Only valid on OF enabled platforms */
-	if (!of_get_mac_address_nvmem(to_of_node(fwnode), fw_mac_addr)) {
+	ret = of_get_mac_address_nvmem(to_of_node(fwnode), fw_mac_addr);
+	if (ret == -EPROBE_DEFER)
+		return ret;
+	if (!ret) {
 		*mac_from = "nvmem cell";
 		eth_hw_addr_set(dev, fw_mac_addr);
-		return;
+		return 0;
 	}
 
 	*mac_from = "random";
 	eth_hw_addr_random(dev);
+
+	return 0;
 }
 
 static struct mvpp2_port *mvpp2_phylink_to_port(struct phylink_config *config)
@@ -6815,7 +6821,9 @@ static int mvpp2_port_probe(struct platform_device *pdev,
 	mutex_init(&port->gather_stats_lock);
 	INIT_DELAYED_WORK(&port->stats_work, mvpp2_gather_hw_statistics);
 
-	mvpp2_port_copy_mac_addr(dev, priv, port_fwnode, &mac_from);
+	err = mvpp2_port_copy_mac_addr(dev, priv, port_fwnode, &mac_from);
+	if (err < 0)
+		goto err_free_stats;
 
 	port->tx_ring_size = MVPP2_MAX_TXD_DFLT;
 	port->rx_ring_size = MVPP2_MAX_RXD_DFLT;