mediatek: Add support for Xiaomi Redmi Router AX6S

Also known as the "Xiaomi Router AX3200" in western markets,
but only the AX6S is widely installation-capable at this time.

SoC: MediaTek MT7622B
RAM: DDR3 256 MiB (ESMT M15T2G16128A)
Flash: SPI-NAND 128 MiB (ESMT F50L1G41LB or Gigadevice GD5F1GQ5xExxG)
WLAN: 2.4/5 GHz 4T4R
2.4 GHz: MediaTek MT7622B
5 GHz: MediaTek MT7915E
Ethernet: 4x 10/100/1000 Mbps
Switch: MediaTek MT7531B
LEDs/Keys: 2/2 (Internet + System LED, Mesh button + Reset pin)
UART: Marked J1 on board VCC RX GND TX, beginning from "1". 3.3v, 115200n8
Power: 12 VDC, 1.5 A

Notes:
U-Boot passes through the ethaddr from uboot-env partition,
but also has been known to reset it to a generic mac address
hardcoded in the bootloader.

However, bdata is also populated with the ethernet mac addresses,
but is also typically never written to. Thus this is used instead.

Installation:
1. Flash stock Xiaomi "closed beta" image labelled
'miwifi_rb03_firmware_stable_1.2.7_closedbeta.bin'.
(MD5: 5eedf1632ac97bb5a6bb072c08603ed7)

2. Calculate telnet password from serial number and login

3. Execute commands to prepare device
nvram set ssh_en=1
nvram set uart_en=1
nvram set boot_wait=on
nvram set flag_boot_success=1
nvram set flag_try_sys1_failed=0
nvram set flag_try_sys2_failed=0
nvram commit

4. Download and flash image
On computer:
python -m http.server
On router:
cd /tmp
wget http://<IP>:8000/factory.bin
mtd -r write factory.bin firmware

Device should reboot at this point.

Reverting to stock:
Stock Xiaomi recovery tftp that accepts their signed images,
with default ips of 192.168.31.1 + 192.168.31.100.
Stock image should be renamed to tftp server ip in hex (Eg. C0A81F64.img)
Triggered by holding reset pin on powerup.

A simple implementation of this would be via dnsmasq's
dhcp-boot option or using the vendor's (Windows only)
recovery tool available on their website.

Signed-off-by: Richard Huynh <voxlympha@gmail.com>

package/boot/uboot-envtools/files/mediatek_mt7622

@@ -41,6 +41,9 @@ ruijie,rg-ew3200gx-pro)
 ubnt,unifi-6-lr-ubootmod)
 	ubootenv_add_uci_config "/dev/mtd2" "0x0" "0x4000" "0x10000"
 	;;
+xiaomi,redmi-router-ax6s)
+	ubootenv_add_uci_config "/dev/mtd3" "0x0" "0x10000" "0x40000"
+	;;
 esac
 
 config_load ubootenv

target/linux/mediatek/dts/mt7622-xiaomi-redmi-router-ax6s.dts

@@ -0,0 +1,355 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
+/dts-v1/;
+
+#include <dt-bindings/input/input.h>
+#include <dt-bindings/gpio/gpio.h>
+
+#include "mt7622.dtsi"
+#include "mt6380.dtsi"
+
+/ {
+	model = "Xiaomi Redmi Router AX6S";
+	compatible = "xiaomi,redmi-router-ax6s", "mediatek,mt7622";
+
+	aliases {
+		serial0 = &uart0;
+		led-boot = &led_power_amber;
+		led-failsafe = &led_power_amber;
+		led-running = &led_power_blue;
+		led-upgrade = &led_power_blue;
+	};
+
+	chosen {
+		stdout-path = "serial0:115200n8";
+		bootargs = "earlycon=uart8250,mmio32,0x11002000 console=ttyS0,115200n8 swiotlb=512";
+	};
+
+	memory {
+		reg = <0 0x40000000 0 0x8000000>;
+	};
+
+	leds {
+		compatible = "gpio-leds";
+
+		led_power_blue: power_blue {
+			label = "blue:power";
+			gpios = <&pio 18 GPIO_ACTIVE_LOW>;
+		};
+
+		led_power_amber: power_amber {
+			label = "amber:power";
+			gpios = <&pio 17 GPIO_ACTIVE_LOW>;
+		};
+
+		led_net_blue: net_blue {
+			label = "blue:net";
+			gpios = <&pio 01 GPIO_ACTIVE_LOW>;
+		};
+
+		led_net_amber: net_amber {
+			label = "amber:net";
+			gpios = <&pio 16 GPIO_ACTIVE_LOW>;
+		};
+
+	};
+
+	keys {
+		compatible = "gpio-keys";
+
+		reset {
+			label = "reset";
+			gpios = <&pio 0 GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_RESTART>;
+		};
+
+		mesh {
+			label = "mesh";
+			gpios = <&pio 102 GPIO_ACTIVE_LOW>;
+			linux,code = <BTN_9>;
+			linux,input-type = <EV_SW>;
+		};
+	};
+};
+
+&cpu0 {
+	proc-supply = <&mt6380_vcpu_reg>;
+	sram-supply = <&mt6380_vm_reg>;
+};
+
+&cpu1 {
+	proc-supply = <&mt6380_vcpu_reg>;
+	sram-supply = <&mt6380_vm_reg>;
+};
+
+&pio {
+	eth_pins: eth-pins {
+		mux {
+			function = "eth";
+			groups = "mdc_mdio", "rgmii_via_gmac2";
+		};
+	};
+
+	pcie0_pins: pcie0-pins {
+		mux {
+			function = "pcie";
+			groups = "pcie0_pad_perst",
+				 "pcie0_1_waken",
+				 "pcie0_1_clkreq";
+		};
+	};
+
+	pmic_bus_pins: pmic-bus-pins {
+		mux {
+			function = "pmic";
+			groups = "pmic_bus";
+		};
+	};
+
+	pwm7_pins: pwm1-2-pins {
+		mux {
+			function = "pwm";
+			groups = "pwm_ch7_2";
+		};
+	};
+
+	/* Serial NAND is shared pin with SPI-NOR */
+	serial_nand_pins: serial-nand-pins {
+		mux {
+			function = "flash";
+			groups = "snfi";
+		};
+	};
+
+	uart0_pins: uart0-pins {
+		mux {
+			function = "uart";
+			groups = "uart0_0_tx_rx" ;
+		};
+	};
+
+	watchdog_pins: watchdog-pins {
+		mux {
+			function = "watchdog";
+			groups = "watchdog";
+		};
+	};
+};
+
+&eth {
+	pinctrl-names = "default";
+	pinctrl-0 = <&eth_pins>;
+	status = "okay";
+
+	gmac0: mac@0 {
+		compatible = "mediatek,eth-mac";
+		reg = <0>;
+
+		phy-connection-type = "2500base-x";
+
+		nvmem-cells = <&macaddr_factory_4>;
+		nvmem-cell-names = "mac-address";
+		mac-address-increment = <(-1)>;
+
+		fixed-link {
+			speed = <2500>;
+			full-duplex;
+			pause;
+		};
+	};
+
+	mdio-bus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		switch@0 {
+			compatible = "mediatek,mt7531";
+			reg = <0>;
+			interrupt-controller;
+			#interrupt-cells = <1>;
+			interrupt-parent = <&pio>;
+			interrupts = <53 IRQ_TYPE_LEVEL_HIGH>;
+			reset-gpios = <&pio 54 GPIO_ACTIVE_HIGH>;
+
+			ports {
+				#address-cells = <1>;
+				#size-cells = <0>;
+
+				wan: port@1 {
+					reg = <1>;
+					label = "wan";
+				};
+
+				port@2 {
+					reg = <2>;
+					label = "lan1";
+				};
+
+				port@3 {
+					reg = <3>;
+					label = "lan2";
+				};
+
+				port@4 {
+					reg = <4>;
+					label = "lan3";
+				};
+
+				port@6 {
+					reg = <6>;
+					label = "cpu";
+					ethernet = <&gmac0>;
+					phy-mode = "2500base-x";
+
+					fixed-link {
+						speed = <2500>;
+						full-duplex;
+						pause;
+					};
+				};
+			};
+		};
+	};
+};
+
+&snand {
+	pinctrl-names = "default";
+	pinctrl-0 = <&serial_nand_pins>;
+	status = "okay";
+
+	mediatek,bmt-v2;
+	mediatek,bmt-table-size = <0x1000>;
+	mediatek,bmt-remap-range = <0x0 0x6c0000>;
+
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		partition@0 {
+			label = "Preloader";
+			reg = <0x0 0x80000>;
+			read-only;
+		};
+
+		partition@80000 {
+			label = "ATF";
+			reg = <0x80000 0x40000>;
+			read-only;
+		};
+
+		partition@c0000 {
+			label = "u-boot";
+			reg = <0xc0000 0x80000>;
+			read-only;
+		};
+
+		partition@140000 {
+			label = "u-boot-env";
+			reg = <0x140000 0x40000>;
+		};
+
+		partition@180000 {
+			label = "bdata";
+			reg = <0x180000 0x40000>;
+		};
+
+		factory: partition@1c0000 {
+			label = "factory";
+			reg = <0x1c0000 0x80000>;
+			read-only;
+
+			compatible = "nvmem-cells";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			macaddr_factory_4: macaddr@4 {
+				reg = <0x4 0x6>;
+			};
+		};
+
+		partition@240000 {
+			label = "crash";
+			reg = <0x240000 0x40000>;
+			read-only;
+		};
+
+		partition@280000 {
+			label = "crash_log";
+			reg = <0x280000 0x40000>;
+			read-only;
+		};
+
+		/* Shrunk and renamed from "firmware"
+		 * as to not break luci size checks
+		 */
+		partition@2c0000 {
+			label = "kernel";
+			compatible = "denx,fit";
+			reg = <0x2c0000 0x400000>;
+		};
+
+
+		/* ubi partition is the result of squashing
+		 * consecutive stock partitions:
+		 * - firmware (partially)
+		 * - firmware1
+		 * - overlay
+		 * - obr
+		 */
+		partition@6c0000 {
+			label = "ubi";
+			reg = <0x6C0000 0x6f00000>;
+		};
+	};
+};
+
+&pcie0 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pcie0_pins>;
+	status = "okay";
+};
+
+&slot0 {
+	status = "okay";
+
+	wifi@0,0 {
+		compatible = "mediatek,mt76";
+		reg = <0x0000 0 0 0 0>;
+		mediatek,mtd-eeprom = <&factory 0x5000>;
+		ieee80211-freq-limit = <5000000 6000000>;
+	};
+};
+
+&pwm {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pwm7_pins>;
+	status = "okay";
+};
+
+&pwrap {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pmic_bus_pins>;
+	status = "okay";
+};
+
+&rtc {
+	status = "disabled";
+};
+
+&uart0 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&uart0_pins>;
+	status = "okay";
+};
+
+&watchdog {
+	pinctrl-names = "default";
+	pinctrl-0 = <&watchdog_pins>;
+	status = "okay";
+};
+
+&wmac {
+	status = "okay";
+
+	mediatek,mtd-eeprom = <&factory 0x0>;
+};

target/linux/mediatek/image/mt7622.mk

@@ -249,3 +249,23 @@ define Device/ubnt_unifi-6-lr-ubootmod
   ARTIFACT/bl31-uboot.fip := bl31-uboot ubnt_unifi-6-lr
 endef
 TARGET_DEVICES += ubnt_unifi-6-lr-ubootmod
+
+define Device/xiaomi_redmi-router-ax6s
+  DEVICE_VENDOR := Xiaomi
+  DEVICE_MODEL := Redmi Router AX6S
+  DEVICE_ALT0_VENDOR := Xiaomi
+  DEVICE_ALT0_MODEL := Router AX3200
+  DEVICE_DTS := mt7622-xiaomi-redmi-router-ax6s
+  DEVICE_DTS_DIR := ../dts
+  BOARD_NAME := xiaomi,redmi-router-ax6s
+  DEVICE_PACKAGES := kmod-mt7915e
+  UBINIZE_OPTS := -E 5
+  IMAGES += factory.bin
+  BLOCKSIZE := 128k
+  PAGESIZE := 2048
+  KERNEL_SIZE := 4096k
+  KERNEL_INITRAMFS_SUFFIX := -recovery.itb
+  IMAGE/factory.bin := append-kernel | pad-to $$(KERNEL_SIZE) | append-ubi
+  IMAGE/sysupgrade.bin := sysupgrade-tar | append-metadata
+endef
+TARGET_DEVICES += xiaomi_redmi-router-ax6s

target/linux/mediatek/mt7622/base-files/etc/board.d/01_leds

@@ -10,6 +10,9 @@ linksys,e8450|\
 linksys,e8450-ubi)
 	ucidef_set_led_netdev "wan" "WAN" "inet:blue" "wan"
 	;;
+xiaomi,redmi-router-ax6s)
+	ucidef_set_led_netdev "wan" "WAN" "blue:net" "wan"
+	;;
 esac
 
 board_config_flush

target/linux/mediatek/mt7622/base-files/etc/board.d/02_network

@@ -24,6 +24,9 @@ mediatek_setup_interfaces()
 	ubnt,unifi-6-lr-ubootmod)
 		ucidef_set_interface_lan "eth0"
 		;;
+	xiaomi,redmi-router-ax6s)
+		ucidef_set_interfaces_lan_wan "lan1 lan2 lan3" wan
+		;;
 	*)
 		ucidef_add_switch "switch0" \
 				  "0:lan" "1:lan" "2:lan" "3:lan" "4:wan" "6u@eth0" "5u@eth1"
@@ -35,14 +38,22 @@ mediatek_setup_macs()
 {
 	local board="$1"
 	local lan_mac=""
+	local wan_mac=""
+	local label_mac=""
 
 	case $board in
 	ruijie,rg-ew3200gx-pro)
 		lan_mac=$(macaddr_add $(get_mac_label) 1)
 		;;
+	xiaomi,redmi-router-ax6s)
+		wan_mac=$(mtd_get_mac_ascii bdata ethaddr_wan)
+		label_mac=$wan_mac
+		;;
 	esac
 
 	[ -n "$lan_mac" ] && ucidef_set_interface_macaddr "lan" $lan_mac
+	[ -n "$wan_mac" ] && ucidef_set_interface_macaddr "wan" $wan_mac
+	[ -n "$label_mac" ] && ucidef_set_label_macaddr $label_mac
 }
 
 board_config_update

target/linux/mediatek/mt7622/base-files/lib/upgrade/platform.sh

@@ -45,7 +45,8 @@ platform_do_upgrade() {
 		default_do_upgrade "$1"
 		;;
 	mediatek,mt7622-rfb1-ubi|\
-	totolink,a8000ru)
+	totolink,a8000ru|\
+	xiaomi,redmi-router-ax6s)
 		nand_do_upgrade "$1"
 		;;
 	*)
@@ -67,7 +68,8 @@ platform_check_image() {
 		buffalo_check_image "$board" "$magic" "$1" || return 1
 		;;
 	mediatek,mt7622-rfb1-ubi|\
-	totolink,a8000ru)
+	totolink,a8000ru|\
+	xiaomi,redmi-router-ax6s)
 		nand_do_platform_check "$board" "$1"
 		;;
 	*)