ramips: mt7621: support openwrt,netdev-name for renaming interfaces

Edgerouter X currently has its eth1 port on the switch missing since there
is a naming conflict currently.

So, as the root cause is mixing kernel support for DSA interfaces having
predictable names set via "label" property vs others having it assigned
dynamically lets avoid the conflict by using our own custom property as
suggested upstream [1].

So, add support via "openwrt,netdev-name" property and use it on ERX.

Fixes: 2a25c6ace8d8 ("ramips: get rid of downstream network device label patch")
Fixes: #15643
Link: https://github.com/openwrt/openwrt/pull/17062
Signed-off-by: Robert Marko <[email protected]>
(cherry picked from commit 5695267847c2fe51290fdbde6ecd7114654f7988)

target/linux/ramips/dts/mt7621_ubnt_edgerouter-x-sfp.dts

@@ -69,11 +69,12 @@
 	ports {
 		port@5 {
 			reg = <5>;
-			label = "eth5";
+			openwrt,netdev-name = "eth5";
 			phy-handle = <&ephy7>;
 			phy-mode = "rgmii-rxid";
 			nvmem-cells = <&macaddr_factory_22 5>;
 			nvmem-cell-names = "mac-address";
+			/delete-property/ label;
 		};
 	};
 };

target/linux/ramips/dts/mt7621_ubnt_edgerouter-x.dts

@@ -7,7 +7,7 @@
 
 &gmac1 {
 	status = "okay";
-	label = "eth0";
+	openwrt,netdev-name = "eth0";
 	phy-handle = <&ethphy0>;
 
 	nvmem-cells = <&macaddr_factory_22 0>;

target/linux/ramips/dts/mt7621_ubnt_edgerouter-x.dtsi

@@ -22,42 +22,47 @@
 &gmac0 {
 	nvmem-cells = <&macaddr_factory_22 0>;
 	nvmem-cell-names = "mac-address";
-	label = "dsa";
+	openwrt,netdev-name = "dsa";
 };
 
 &switch0 {
 	ports {
 		port@0 {
 			status = "okay";
-			label = "eth0";
+			openwrt,netdev-name = "eth0";
+			/delete-property/ label;
 		};
 
 		port@1 {
 			status = "okay";
-			label = "eth1";
+			openwrt,netdev-name = "eth1";
 			nvmem-cells = <&macaddr_factory_22 1>;
 			nvmem-cell-names = "mac-address";
+			/delete-property/ label;
 		};
 
 		port@2 {
 			status = "okay";
-			label = "eth2";
+			openwrt,netdev-name = "eth2";
 			nvmem-cells = <&macaddr_factory_22 2>;
 			nvmem-cell-names = "mac-address";
+			/delete-property/ label;
 		};
 
 		port@3 {
 			status = "okay";
-			label = "eth3";
+			openwrt,netdev-name = "eth3";
 			nvmem-cells = <&macaddr_factory_22 3>;
 			nvmem-cell-names = "mac-address";
+			/delete-property/ label;
 		};
 
 		port@4 {
 			status = "okay";
-			label = "eth4";
+			openwrt,netdev-name = "eth4";
 			nvmem-cells = <&macaddr_factory_22 4>;
 			nvmem-cell-names = "mac-address";
+			/delete-property/ label;
 		};
 	};
 };

target/linux/ramips/mt7621/base-files/lib/preinit/04_set_netdev_label

@@ -10,6 +10,14 @@ set_netdev_labels() {
 		[ "$netdev" = "$label" ] && continue
 		ip link set "$netdev" name "$label"
 	done
+
+	for dir in /sys/class/net/*; do
+		[ -r "$dir/of_node/openwrt,netdev-name" ] || continue
+		read -r label < "$dir/of_node/openwrt,netdev-name"
+		netdev="${dir##*/}"
+		[ "$netdev" = "$label" ] && continue
+		ip link set "$netdev" name "$label"
+	done
 }
 
 boot_hook_add preinit_main set_netdev_labels