From f10843e04a075202dbb39dfcee047e3a2fdf5a8d Mon Sep 17 00:00:00 2001
From: Michael Walle <michael@walle.cc>
Date: Mon, 12 Apr 2021 19:47:18 +0200
Subject: of: net: fix of_get_mac_addr_nvmem() for non-platform devices

of_get_mac_address() already supports fetching the MAC address by an
nvmem provider. But until now, it was just working for platform devices.
Esp. it was not working for DSA ports and PCI devices. It gets more
common that PCI devices have a device tree binding since SoCs contain
integrated root complexes.

Use the nvmem of_* binding to fetch the nvmem cells by a struct
device_node. We still have to try to read the cell by device first
because there might be a nvmem_cell_lookup associated with that device.

Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/of/of_net.c | 35 ++++++++++++++++++++++++++++++-----
 1 file changed, 30 insertions(+), 5 deletions(-)

--- a/drivers/of/of_net.c
+++ b/drivers/of/of_net.c
@@ -11,6 +11,7 @@
 #include <linux/phy.h>
 #include <linux/export.h>
 #include <linux/device.h>
+#include <linux/nvmem-consumer.h>
 
 /**
  * of_get_phy_mode - Get phy mode for given device_node
@@ -53,15 +54,39 @@ static int of_get_mac_addr(struct device
 static int of_get_mac_addr_nvmem(struct device_node *np, u8 *addr)
 {
 	struct platform_device *pdev = of_find_device_by_node(np);
+	struct nvmem_cell *cell;
+	const void *mac;
+	size_t len;
 	int ret;
 
-	if (!pdev)
-		return -ENODEV;
+	/* Try lookup by device first, there might be a nvmem_cell_lookup
+	 * associated with a given device.
+	 */
+	if (pdev) {
+		ret = nvmem_get_mac_address(&pdev->dev, addr);
+		put_device(&pdev->dev);
+		return ret;
+	}
+
+	cell = of_nvmem_cell_get(np, "mac-address");
+	if (IS_ERR(cell))
+		return PTR_ERR(cell);
+
+	mac = nvmem_cell_read(cell, &len);
+	nvmem_cell_put(cell);
+
+	if (IS_ERR(mac))
+		return PTR_ERR(mac);
+
+	if (len != ETH_ALEN || !is_valid_ether_addr(mac)) {
+		kfree(mac);
+		return -EINVAL;
+	}
 
-	ret = nvmem_get_mac_address(&pdev->dev, addr);
-	put_device(&pdev->dev);
+	memcpy(addr, mac, ETH_ALEN);
+	kfree(mac);
 
-	return ret;
+	return 0;
 }
 
 /**
