net: enetc: fetch MAC address from device tree

Normally, the bootloader will already initialize the MAC address
registers of the ENETC and the driver will just use them or generate a
random one, if it is not initialized.

Add a new way to provide the MAC address: via device tree. Besides the
usual 'mac-address' property, there is also the possibility to fetch it
via a NVMEM provider. The sl28 board stores the MAC address in the SPI
NOR flash OTP region. Having this will allow linux to fetch the MAC
address from there without being dependent on the bootloader.

No in-tree boards have the device tree properties set, thus for these,
this is a no-op.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/enetc/enetc_pf.c

@@ -390,23 +390,54 @@ static int enetc_pf_set_vf_spoofchk(struct net_device *ndev, int vf, bool en)
 	return 0;
 }
 
-static void enetc_port_setup_primary_mac_address(struct enetc_si *si)
+static int enetc_setup_mac_address(struct device_node *np, struct enetc_pf *pf,
+				   int si)
 {
-	unsigned char mac_addr[MAX_ADDR_LEN];
-	struct enetc_pf *pf = enetc_si_priv(si);
-	struct enetc_hw *hw = &si->hw;
-	int i;
+	struct device *dev = &pf->si->pdev->dev;
+	struct enetc_hw *hw = &pf->si->hw;
+	u8 mac_addr[ETH_ALEN] = { 0 };
+	int err;
 
-	/* check MAC addresses for PF and all VFs, if any is 0 set it ro rand */
-	for (i = 0; i < pf->total_vfs + 1; i++) {
-		enetc_pf_get_primary_mac_addr(hw, i, mac_addr);
-		if (!is_zero_ether_addr(mac_addr))
-			continue;
+	/* (1) try to get the MAC address from the device tree */
+	if (np) {
+		err = of_get_mac_address(np, mac_addr);
+		if (err == -EPROBE_DEFER)
+			return err;
+	}
+
+	/* (2) bootloader supplied MAC address */
+	if (is_zero_ether_addr(mac_addr))
+		enetc_pf_get_primary_mac_addr(hw, si, mac_addr);
+
+	/* (3) choose a random one */
+	if (is_zero_ether_addr(mac_addr)) {
 		eth_random_addr(mac_addr);
-		dev_info(&si->pdev->dev, "no MAC address specified for SI%d, using %pM\n",
-			 i, mac_addr);
-		enetc_pf_set_primary_mac_addr(hw, i, mac_addr);
+		dev_info(dev, "no MAC address specified for SI%d, using %pM\n",
+			 si, mac_addr);
 	}
+
+	enetc_pf_set_primary_mac_addr(hw, si, mac_addr);
+
+	return 0;
+}
+
+static int enetc_setup_mac_addresses(struct device_node *np,
+				     struct enetc_pf *pf)
+{
+	int err, i;
+
+	/* The PF might take its MAC from the device tree */
+	err = enetc_setup_mac_address(np, pf, 0);
+	if (err)
+		return err;
+
+	for (i = 0; i < pf->total_vfs; i++) {
+		err = enetc_setup_mac_address(NULL, pf, i + 1);
+		if (err)
+			return err;
+	}
+
+	return 0;
 }
 
 static void enetc_port_assign_rfs_entries(struct enetc_si *si)
@@ -562,9 +593,6 @@ static void enetc_configure_port(struct enetc_pf *pf)
 	/* split up RFS entries */
 	enetc_port_assign_rfs_entries(pf->si);
 
-	/* fix-up primary MAC addresses, if not set already */
-	enetc_port_setup_primary_mac_address(pf->si);
-
 	/* enforce VLAN promisc mode for all SIs */
 	pf->vlan_promisc_simap = ENETC_VLAN_PROMISC_MAP_ALL;
 	enetc_set_vlan_promisc(hw, pf->vlan_promisc_simap);
@@ -1137,6 +1165,10 @@ static int enetc_pf_probe(struct pci_dev *pdev,
 	pf->si = si;
 	pf->total_vfs = pci_sriov_get_totalvfs(pdev);
 
+	err = enetc_setup_mac_addresses(node, pf);
+	if (err)
+		goto err_setup_mac_addresses;
+
 	enetc_configure_port(pf);
 
 	enetc_get_si_caps(si);
@@ -1204,6 +1236,7 @@ static int enetc_pf_probe(struct pci_dev *pdev,
 err_init_port_rss:
 err_init_port_rfs:
 err_device_disabled:
+err_setup_mac_addresses:
 	enetc_teardown_cbdr(&si->cbd_ring);
 err_setup_cbdr:
 err_map_pf_space: