Merge branch 'eth_hw_addr_gen-for-switches'

Jakub Kicinski says:

====================
ethernet: add eth_hw_addr_gen() for switches

While doing the last polishing of the drivers/ethernet
changes I realized we have a handful of drivers offsetting
some base MAC addr by an id. So I decided to add a helper
for it. The helper takes care of wrapping which is probably
not 100% necessary but seems like a good idea. And it saves
driver side LoC (the diffstat is actually negative if we
compare against the changes I'd have to make if I was to
convert all these drivers to not operate directly on
netdev->dev_addr).
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/fec_main.c

@@ -1768,11 +1768,8 @@ static int fec_get_mac(struct net_device *ndev)
 		return 0;
 	}
 
-	eth_hw_addr_set(ndev, iap);
-
 	/* Adjust MAC if using macaddr */
-	if (iap == macaddr)
-		 ndev->dev_addr[ETH_ALEN-1] = macaddr[ETH_ALEN-1] + fep->dev_id;
+	eth_hw_addr_gen(ndev, iap, iap == macaddr ? fep->dev_id : 0);
 
 	return 0;
 }

drivers/net/ethernet/marvell/prestera/prestera_main.c

@@ -338,11 +338,14 @@ static int prestera_port_create(struct prestera_switch *sw, u32 id)
 		goto err_port_init;
 	}
 
+	eth_hw_addr_gen(dev, sw->base_mac, port->fp_id);
 	/* firmware requires that port's MAC address consist of the first
 	 * 5 bytes of the base MAC address
 	 */
-	memcpy(dev->dev_addr, sw->base_mac, dev->addr_len - 1);
-	dev->dev_addr[dev->addr_len - 1] = port->fp_id;
+	if (memcmp(dev->dev_addr, sw->base_mac, ETH_ALEN - 1)) {
+		dev_warn(prestera_dev(sw), "Port MAC address wraps for port(%u)\n", id);
+		dev_addr_mod(dev, 0, sw->base_mac, ETH_ALEN - 1);
+	}
 
 	err = prestera_hw_port_mac_set(port, dev->dev_addr);
 	if (err) {

drivers/net/ethernet/mellanox/mlxsw/minimal.c

@@ -200,20 +200,16 @@ static int
 mlxsw_m_port_dev_addr_get(struct mlxsw_m_port *mlxsw_m_port)
 {
 	struct mlxsw_m *mlxsw_m = mlxsw_m_port->mlxsw_m;
-	struct net_device *dev = mlxsw_m_port->dev;
 	char ppad_pl[MLXSW_REG_PPAD_LEN];
+	u8 addr[ETH_ALEN];
 	int err;
 
 	mlxsw_reg_ppad_pack(ppad_pl, false, 0);
 	err = mlxsw_reg_query(mlxsw_m->core, MLXSW_REG(ppad), ppad_pl);
 	if (err)
 		return err;
-	mlxsw_reg_ppad_mac_memcpy_from(ppad_pl, dev->dev_addr);
-	/* The last byte value in base mac address is guaranteed
-	 * to be such it does not overflow when adding local_port
-	 * value.
-	 */
-	dev->dev_addr[ETH_ALEN - 1] += mlxsw_m_port->module + 1;
+	mlxsw_reg_ppad_mac_memcpy_from(ppad_pl, addr);
+	eth_hw_addr_gen(mlxsw_m_port->dev, addr, mlxsw_m_port->module + 1);
 	return 0;
 }
 

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -316,11 +316,11 @@ static int mlxsw_sp_port_dev_addr_set(struct mlxsw_sp_port *mlxsw_sp_port,
 static int mlxsw_sp_port_dev_addr_init(struct mlxsw_sp_port *mlxsw_sp_port)
 {
 	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
-	unsigned char *addr = mlxsw_sp_port->dev->dev_addr;
 
-	ether_addr_copy(addr, mlxsw_sp->base_mac);
-	addr[ETH_ALEN - 1] += mlxsw_sp_port->local_port;
-	return mlxsw_sp_port_dev_addr_set(mlxsw_sp_port, addr);
+	eth_hw_addr_gen(mlxsw_sp_port->dev, mlxsw_sp->base_mac,
+			mlxsw_sp_port->local_port);
+	return mlxsw_sp_port_dev_addr_set(mlxsw_sp_port,
+					  mlxsw_sp_port->dev->dev_addr);
 }
 
 static int mlxsw_sp_port_max_mtu_get(struct mlxsw_sp_port *mlxsw_sp_port, int *p_max_mtu)

drivers/net/ethernet/microchip/sparx5/sparx5_netdev.c

@@ -200,7 +200,6 @@ struct net_device *sparx5_create_netdev(struct sparx5 *sparx5, u32 portno)
 {
 	struct sparx5_port *spx5_port;
 	struct net_device *ndev;
-	u64 val;
 
 	ndev = devm_alloc_etherdev(sparx5->dev, sizeof(struct sparx5_port));
 	if (!ndev)
@@ -216,8 +215,7 @@ struct net_device *sparx5_create_netdev(struct sparx5 *sparx5, u32 portno)
 	ndev->netdev_ops = &sparx5_port_netdev_ops;
 	ndev->ethtool_ops = &sparx5_ethtool_ops;
 
-	val = ether_addr_to_u64(sparx5->base_mac) + portno + 1;
-	u64_to_ether_addr(val, ndev->dev_addr);
+	eth_hw_addr_gen(ndev, sparx5->base_mac, portno + 1);
 
 	return ndev;
 }

drivers/net/ethernet/mscc/ocelot_net.c

@@ -1705,8 +1705,7 @@ int ocelot_probe_port(struct ocelot *ocelot, int port, struct regmap *target,
 		NETIF_F_HW_TC;
 	dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER | NETIF_F_HW_TC;
 
-	eth_hw_addr_set(dev, ocelot->base_mac);
-	dev->dev_addr[ETH_ALEN - 1] += port;
+	eth_hw_addr_gen(dev, ocelot->base_mac, port);
 	ocelot_mact_learn(ocelot, PGID_CPU, dev->dev_addr,
 			  ocelot_port->pvid_vlan.vid, ENTRYTYPE_LOCKED);
 

include/linux/etherdevice.h

@@ -551,6 +551,27 @@ static inline unsigned long compare_ether_header(const void *a, const void *b)
 #endif
 }
 
+/**
+ * eth_hw_addr_gen - Generate and assign Ethernet address to a port
+ * @dev: pointer to port's net_device structure
+ * @base_addr: base Ethernet address
+ * @id: offset to add to the base address
+ *
+ * Generate a MAC address using a base address and an offset and assign it
+ * to a net_device. Commonly used by switch drivers which need to compute
+ * addresses for all their ports. addr_assign_type is not changed.
+ */
+static inline void eth_hw_addr_gen(struct net_device *dev, const u8 *base_addr,
+				   unsigned int id)
+{
+	u64 u = ether_addr_to_u64(base_addr);
+	u8 addr[ETH_ALEN];
+
+	u += id;
+	u64_to_ether_addr(u, addr);
+	eth_hw_addr_set(dev, addr);
+}
+
 /**
  * eth_skb_pad - Pad buffer to mininum number of octets for Ethernet frame
  * @skb: Buffer to pad