[PATCH v1] ARM: i.MX8MP: skov: add MAC address assignment support

[Oleksij Rempel]

Assign MAC address to main CPU interface and switch ports.

Signed-off-by: Oleksij Rempel <o.rempel at pengutronix.de>
---
 arch/arm/boards/skov-imx8mp/board.c | 131 ++++++++++++++++++++++++++++
 arch/arm/dts/imx8mp-skov.dts        |   1 +
 2 files changed, 132 insertions(+)

diff --git a/arch/arm/boards/skov-imx8mp/board.c b/arch/arm/boards/skov-imx8mp/board.c
index 3b6eb7b080..94d0bc75f9 100644
--- a/arch/arm/boards/skov-imx8mp/board.c
+++ b/arch/arm/boards/skov-imx8mp/board.c
@@ -10,9 +10,12 @@
 #include <gpio.h>
 #include <init.h>
 #include <io.h>
+#include <linux/nvmem-consumer.h>
 #include <mach/imx/bbu.h>
 #include <mach/imx/generic.h>
 #include <mach/imx/iomux-mx8mp.h>
+#include <net.h>
+#include <of_net.h>
 
 struct skov_imx8mp_priv {
 	struct device *dev;
@@ -85,6 +88,134 @@ static const struct board_description imx8mp_variants[] = {
 	},
 };
 
+static void skov_imx8mp_get_src_mac(struct skov_imx8mp_priv *priv,
+				   struct device_node *s_np, u8 *mac,
+				   int dst_id)
+{
+	char str[sizeof("xx:xx:xx:xx:xx:xx")];
+	struct eth_device *s_edev;
+	int ret;
+
+	s_edev = of_find_eth_device_by_node(s_np);
+	if (s_edev && is_valid_ether_addr(s_edev->ethaddr)) {
+		/* If the source device has a valid MAC address, use it in
+		 * case address is overwritten by user.
+		 */
+		memcpy(mac, s_edev->ethaddr, ETH_ALEN);
+		return;
+	}
+
+	/* if the source device has no valid MAC address, try to get it from
+	 * nvmem if it configured in the devicetree.
+	 */
+	ret = of_get_mac_addr_nvmem(s_np, mac);
+	if (!ret)
+		return;
+
+	/* if the source device has no valid MAC address, generate one with
+	 * vendor OUI.
+	 */
+	ret = generate_ether_addr(mac, dst_id);
+	if (ret)
+		random_ether_addr(mac);
+
+	/* set SKOV OUI */
+	mac[0] = 0x00;
+	mac[1] = 0x0e;
+	mac[2] = 0xcd;
+	ethaddr_to_string(mac, str);
+	dev_warn(priv->dev, "Failed to get eth addr for idx=%d. Generating one: %s\n",
+		 dst_id, str);
+}
+
+static int skov_imx8mp_eth_register_ethaddr(struct skov_imx8mp_priv *priv,
+					    struct device_node *d_np,
+					    struct device_node *s_np,
+					    int dst_id)
+{
+	struct eth_device *d_edev;
+	u8 mac[ETH_ALEN] = { 0 };
+
+	d_edev = of_find_eth_device_by_node(d_np);
+	if (d_edev) {
+		/* If the destination device already has a valid MAC address, do
+		 * nothing, it was probably set to nv by user.
+		 */
+		if (is_valid_ether_addr(d_edev->ethaddr))
+			return 0;
+	}
+
+	skov_imx8mp_get_src_mac(priv, s_np, mac, dst_id);
+
+	of_eth_register_ethaddr(d_np, mac);
+
+	return 0;
+}
+
+/* We have following requirements for the ethernet MAC addresses:
+ * - LAN1 MAC address should be the same as the MAC address stored in the FEC
+ *   slot (FEC is not used on this board).
+ * - LAN2 MAC address should be the same as the EQOS MAC address. (EQOS is
+ *   the master interface for the switch on this board, LAN2 and LAN1 are
+ *   external ports of this switch).
+ * - LAN2 MAC address is usually higher than LAN1 MAC address. But production
+ *   process do not guarantee this. So, we can't calculate LAN2 MAC address
+ *   from LAN1 MAC address.
+ */
+static void skov_imx8mp_ethernet_init(struct skov_imx8mp_priv *priv)
+{
+	struct device_node *root;
+	unsigned int i;
+	struct eth_node_info {
+		const char *s_alias;
+		const char *d_alias;
+	} eth_node_info[] = {
+		{ "ethernet0", "ethernet0" }, /* EQOS -> EQOS */
+		{ "ethernet0", "ethernet2" }, /* EQOS -> LAN2 */
+		{ "ethernet3", "ethernet1" }, /* FEC -> LAN1 */
+	};
+
+	root = of_get_root_node();
+
+	for (i = 0; i < ARRAY_SIZE(eth_node_info); i++) {
+		const char *s_alias = eth_node_info[i].s_alias;
+		const char *d_alias = eth_node_info[i].d_alias;
+		struct device_node *s_np, *d_np;
+		int ret;
+
+		s_np = of_find_node_by_alias(root, s_alias);
+		if (!s_np) {
+			dev_warn(priv->dev, "Failed to find src ethernet node by alias: %s\n",
+				 s_alias);
+			continue;
+		}
+
+		d_np = of_find_node_by_alias(root, d_alias);
+		if (!d_np) {
+			dev_warn(priv->dev, "Failed to find dst ethernet node by alias: %s\n",
+				 d_alias);
+			continue;
+		}
+
+		ret = skov_imx8mp_eth_register_ethaddr(priv, d_np, s_np, i);
+		if (ret) {
+			dev_warn(priv->dev, "Failed to transfer MAC address from alias %s to %s\n",
+				 s_alias, d_alias);
+			continue;
+		}
+	}
+}
+
+static int skov_imx8mp_populate_ethaddr(void)
+{
+	struct skov_imx8mp_priv *priv = skov_imx8mp_priv;
+
+	skov_imx8mp_ethernet_init(priv);
+
+	return 0;
+}
+postenvironment_initcall(skov_imx8mp_populate_ethaddr);
+
 static int skov_imx8mp_fixup(struct device_node *root, void *data)
 {
 	struct device_node *chosen = of_create_node(root, "/chosen");
diff --git a/arch/arm/dts/imx8mp-skov.dts b/arch/arm/dts/imx8mp-skov.dts
index 3243a41697..063861427c 100644
--- a/arch/arm/dts/imx8mp-skov.dts
+++ b/arch/arm/dts/imx8mp-skov.dts
@@ -31,6 +31,7 @@ aliases {
 		ethernet0 = &eqos;
 		ethernet1 = &lan1;
 		ethernet2 = &lan2;
+		ethernet3 = &fec;
 		state = &state;
 	};
 
-- 
2.39.2