ramips: add support for ASUS 4G-AX56

Specifications:
- Device: ASUS 4g-AX56
- SoC: MT7621AT
- Flash: 128MB
- RAM: 512MB
- Switch: 1 WAN, 4 LAN (10/100/1000 Mbps)
- WiFi: MT7905 2x2 2.4G + MT7975 2x2 5G
- LTE : Fibocom FG621-EA
- LEDs: 1x POWER (white, configurable)
	1x 2.4G (white, not configurable)
	1x 5G (white, not configurable)
        1x WAN (white, not configurable)
        1x 3G/4G (white, not configurable)
	3x signal (white, not configurable)

Flash by U-Boot TFTP method:
- Configure your PC with IP 192.168.0.2
- Set up TFTP server and put the factory.bin image on your PC
- Connect serial port(rate:115200) and turn on AP, then interrupt "U-Boot Boot Menu" by hitting any key
   Select "2. Upgrade firmware"
   Press enter when show "Run firmware after upgrading? (Y/n):"
   Select 0 for TFTP method
   Input U-Boot's IP address: 192.168.0.1
   Input TFTP server's IP address: 192.168.0.2
   Input IP netmask: 255.255.255.0
   Input file name: openwrt-ramips-mt7621-asus_4g-ax56-squashfs-factory.bin
- Restart AP aftre see the log "Firmware upgrade completed!"

Notice:
- LTE module is disable after flash openwrt image so you must active LTE by following two AT command
   echo -e "AT+GTAUTOCONNECT=1\r\n" > /dev/ttyUSB0
   echo -e "AT+GTRNDIS=1,1\r\n" > /dev/ttyUSB0
- After finish AT command once, you don't need to input command later even if reboot/restore default

Signed-off-by: Chuncheng Chen <ccchen1984@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/16752
Signed-off-by: John Crispin <john@phrozen.org>

package/boot/uboot-envtools/files/ramips

@@ -69,6 +69,7 @@ zte,mf283plus)
 	;;
 asus,rt-ax53u|\
 asus,rt-ax54|\
+asus,4g-ax56|\
 belkin,rt1800|\
 elecom,wrc-x1800gs|\
 h3c,tx1800-plus|\

target/linux/ramips/dts/mt7621_asus_4g-ax56.dts

@@ -0,0 +1,211 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
+
+#include "mt7621.dtsi"
+
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/input/input.h>
+#include <dt-bindings/leds/common.h>
+
+/ {
+	compatible = "asus,4g-ax56", "mediatek,mt7621-soc";
+	model = "ASUS 4G-AX56";
+
+	aliases {
+		led-boot = &led_power;
+		led-failsafe = &led_power;
+		led-running = &led_power;
+		led-upgrade = &led_power;
+		label-mac-device = &gmac0;
+	};
+
+	chosen {
+		bootargs = "console=ttyS0,115200";
+		bootargs-override = "console=ttyS0,115200";
+	};
+
+	leds {
+		compatible = "gpio-leds";
+
+		led_power: power {
+			color = <LED_COLOR_ID_WHITE>;
+			function = LED_FUNCTION_POWER;
+			gpios = <&gpio 14 GPIO_ACTIVE_HIGH>;
+		};
+	};
+
+	keys {
+		compatible = "gpio-keys";
+
+		key-restart {
+			label = "reset";
+			gpios = <&gpio 8 GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_RESTART>;
+		};
+
+		key-wps {
+			label = "wps";
+			gpios = <&gpio 4 GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_WPS_BUTTON>;
+		};
+	};
+};
+
+&nand {
+	status = "okay";
+
+	mediatek,nmbm;
+	mediatek,bmt-remap-range =
+		<0x000000 0x7e0000>,
+		<0x35e0000 0x7800000>;
+
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		partition@0 {
+			label = "u-boot";
+			reg = <0x0 0x80000>;
+			read-only;
+		};
+
+		/*
+		 * u-boot gets split here while keeping u-boot read-only,
+		 * which allows safe usage of fw_setenv
+		 */
+		partition@80000 {
+			label = "u-boot-env";
+			reg = <0x80000 0x60000>;
+		};
+
+		partition@e0000 {
+			label = "nvram";
+			reg = <0xe0000 0x100000>;
+			read-only;
+		};
+
+		partition@1e0000 {
+			label = "factory";
+			reg = <0x1e0000 0x100000>;
+			read-only;
+
+			nvmem-layout {
+				compatible = "fixed-layout";
+				#address-cells = <1>;
+				#size-cells = <1>;
+
+				eeprom_factory_0: eeprom@0 {
+					reg = <0x0 0xe00>;
+				};
+
+				macaddr_factory_4: macaddr@4 {
+					reg = <0x4 0x6>;
+				};
+
+				precal_factory_e10: precal@e10 {
+					reg = <0xe10 0x19c10>;
+				};
+			};
+		};
+
+		partition@2e0000 {
+			label = "factory2";
+			reg = <0x2e0000 0x100000>;
+			read-only;
+		};
+
+		partition@3e0000 {
+			label = "firmware";
+			reg = <0x3e0000 0x3200000>;
+
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			partition@0 {
+				label = "kernel";
+				reg = <0x0 0x400000>;
+			};
+
+			partition@400000 {
+				label = "ubi";
+				reg = <0x400000 0x2e00000>;
+			};
+		};
+
+		partition@35e0000 {
+			label = "firmware2";
+			reg = <0x35e0000 0x3200000>;
+		};
+
+		partition@67e0000 {
+			label = "jffs2";
+			reg = <0x67e0000 0x1020000>;
+		};
+
+		/* Last 8M are reserved for NMBM management (bad blocks) */
+	};
+};
+
+&pcie {
+	status = "okay";
+};
+
+&pcie1 {
+	wifi@0,0 {
+		compatible = "mediatek,mt76";
+		reg = <0x0000 0 0 0 0>;
+		nvmem-cells = <&eeprom_factory_0>, <&precal_factory_e10>;
+		nvmem-cell-names = "eeprom", "precal";
+		mediatek,disable-radar-background;
+	};
+};
+
+&gmac0 {
+	nvmem-cells = <&macaddr_factory_4>;
+	nvmem-cell-names = "mac-address";
+};
+
+&gmac1 {
+	status = "okay";
+	label = "wan";
+	phy-handle = <&ethphy0>;
+
+	nvmem-cells = <&macaddr_factory_4>;
+	nvmem-cell-names = "mac-address";
+};
+
+&ethphy0 {
+	/delete-property/ interrupts;
+};
+
+&switch0 {
+	ports {
+		port@1 {
+			status = "okay";
+			label = "lan1";
+		};
+
+		port@2 {
+			status = "okay";
+			label = "lan2";
+		};
+
+		port@3 {
+			status = "okay";
+			label = "lan3";
+		};
+
+		port@4 {
+			status = "okay";
+			label = "lan4";
+		};
+	};
+};
+
+&state_default {
+	gpio {
+		groups = "i2c", "uart2", "uart3", "jtag", "wdt";
+		function = "gpio";
+	};
+};

target/linux/ramips/image/mt7621.mk

@@ -471,6 +471,20 @@ define Device/asus_rt-ax54
 endef
 TARGET_DEVICES += asus_rt-ax54
 
+define Device/asus_4g-ax56
+  $(Device/nand)
+  $(Device/uimage-lzma-loader)
+  DEVICE_VENDOR := ASUS
+  DEVICE_MODEL := 4G-AX56
+  IMAGE_SIZE := 51200k
+  IMAGES += factory.bin
+  IMAGE/factory.bin := append-kernel | pad-to $$(KERNEL_SIZE) | append-ubi | \
+	check-size
+  DEVICE_PACKAGES := kmod-mt7915-firmware kmod-usb3 kmod-usb-serial-option \
+	kmod-usb-net-cdc-ncm
+endef
+TARGET_DEVICES += asus_4g-ax56
+
 define Device/beeline_smartbox-flash
   $(Device/nand)
   $(Device/uimage-lzma-loader)

target/linux/ramips/mt7621/base-files/lib/upgrade/platform.sh

@@ -74,6 +74,7 @@ platform_do_upgrade() {
 	asus,rt-ac85p|\
 	asus,rt-ax53u|\
 	asus,rt-ax54|\
+	asus,4g-ax56|\
 	beeline,smartbox-flash|\
 	beeline,smartbox-giga|\
 	beeline,smartbox-pro|\