ramips: add support for ELECOM WMC-M1267GST2

ELECOM WMC-M1267GST2 is a 2.4/5 GHz band 11ac (Wi-Fi 5) mesh router,
based on MT7621A.

Specification:

- SoC          : MediaTek MT7621A
- RAM          : DDR3 256 MiB (Nanya NT5CC128M16JR-EK)
- Flash        : SPI-NOR 32 MiB (Winbond W25Q256JVFIQ)
- WLAN         : 2.4/5 GHz 2T2R (MediaTek MT7615D)
- Ethernet     : 10/100/1000 Mbps x5
  - switch     : MediaTek MT7530 (SoC)
- LEDs/Keys    : 6x/6x
- UART         : through-hole on PCB ("J4")
  - arrangement: 3.3V, GND, TX, RX from tri-angle marking
  - settings   : 57600n8
- Power        : 12 VDC, 1 A

Flash instruction using factory image:

1. Boot WMC-M1267GST2 normally with "Router" mode
2. Access to "http://192.168.2.1/" and open firmware update page
   ("ファームウェア更新")
3. Select the OpenWrt factory image and click apply ("適用") button
4. Wait ~120 seconds to complete flashing

MAC addresses:

LAN    : 04:AB:18:xx:xx:61 (Factory, 0xFFF4 (hex))
WAN    : 04:AB:18:xx:xx:62 (Factory, 0xFFFA (hex))
2.4 GHz: 04:AB:18:xx:xx:63
5 GHz  : 04:AB:18:xx:xx:64 (Factory, 0x4 (hex))

Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>

target/linux/ramips/dts/mt7621_elecom_wmc-m1267gst2.dts

@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
+
+#include "mt7621_elecom_wrc-gs-1pci.dtsi"
+
+/ {
+	compatible = "elecom,wmc-m1267gst2", "mediatek,mt7621-soc";
+	model = "ELECOM WMC-M1267GST2";
+};
+
+&gmac0 {
+	nvmem-cells = <&macaddr_factory_fff4>;
+	nvmem-cell-names = "mac-address";
+};
+
+&gmac1 {
+	nvmem-cells = <&macaddr_factory_fffa>;
+	nvmem-cell-names = "mac-address";
+};
+
+&partitions {
+	partition@50000 {
+		compatible = "denx,uimage";
+		label = "firmware";
+		reg = <0x50000 0x1800000>;
+	};
+
+	partition@1850000 {
+		label = "tm_pattern";
+		reg = <0x1850000 0x400000>;
+		read-only;
+	};
+
+	partition@1c50000 {
+		label = "tm_key";
+		reg = <0x1c50000 0x100000>;
+		read-only;
+	};
+
+	partition@1d50000 {
+		label = "nvram";
+		reg = <0x1d50000 0xb0000>;
+		read-only;
+	};
+
+	partition@1e00000 {
+		label = "user_data";
+		reg = <0x1e00000 0x200000>;
+		read-only;
+	};
+};
+
+&wifi {
+	nvmem-cells = <&macaddr_factory_4 (-1)>;
+	nvmem-cell-names = "mac-address";
+};
+
+&factory {
+	nvmem-layout {
+		compatible = "fixed-layout";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		macaddr_factory_4: macaddr@4 {
+			compatible = "mac-base";
+			reg = <0x4 0x6>;
+			#nvmem-cell-cells = <1>;
+		};
+
+		macaddr_factory_fff4: macaddr@fff4 {
+			reg = <0xfff4 0x6>;
+		};
+
+		macaddr_factory_fffa: macaddr@fffa {
+			reg = <0xfffa 0x6>;
+		};
+	};
+};

target/linux/ramips/image/mt7621.mk

@@ -979,6 +979,25 @@ define Device/edimax_rg21s
 endef
 TARGET_DEVICES += edimax_rg21s
 
+define Device/elecom_wrc-gs
+  $(Device/dsa-migration)
+  $(Device/uimage-lzma-loader)
+  DEVICE_VENDOR := ELECOM
+  IMAGES += factory.bin
+  IMAGE/factory.bin := $$(sysupgrade_bin) | check-size | \
+	elecom-wrc-gs-factory $$$$(ELECOM_HWNAME) 0.00 -N | \
+	append-string MT7621_ELECOM_$$$$(ELECOM_HWNAME)
+  DEVICE_PACKAGES := kmod-mt7615-firmware -uboot-envtools
+endef
+
+define Device/elecom_wmc-m1267gst2
+  $(Device/elecom_wrc-gs)
+  IMAGE_SIZE := 24576k
+  DEVICE_MODEL := WMC-M1267GST2
+  ELECOM_HWNAME := WMC-DLGST2
+endef
+TARGET_DEVICES += elecom_wmc-m1267gst2
+
 define Device/elecom_wrc-1167ghbk2-s
   $(Device/dsa-migration)
   IMAGE_SIZE := 15488k
@@ -991,17 +1010,6 @@ define Device/elecom_wrc-1167ghbk2-s
 endef
 TARGET_DEVICES += elecom_wrc-1167ghbk2-s
 
-define Device/elecom_wrc-gs
-  $(Device/dsa-migration)
-  $(Device/uimage-lzma-loader)
-  DEVICE_VENDOR := ELECOM
-  IMAGES += factory.bin
-  IMAGE/factory.bin := $$(sysupgrade_bin) | check-size | \
-	elecom-wrc-gs-factory $$$$(ELECOM_HWNAME) 0.00 -N | \
-	append-string MT7621_ELECOM_$$$$(ELECOM_HWNAME)
-  DEVICE_PACKAGES := kmod-mt7615-firmware -uboot-envtools
-endef
-
 define Device/elecom_wrc-1167gs2-b
   $(Device/elecom_wrc-gs)
   IMAGE_SIZE := 11264k