mediatek: MERCUSYS MR90X v1: add OpenWrt U-Boot (UBI) layout

This commit adds OpenWrt U-Boot (UBI) layout support for MERCUSYS MR90X
v1.

Stock U-Boot UBI size:   50 MiB
OpenWrt U-boot UBI size: 126 MiB

Install
-------
1. Perform steps 1-14 of the OpenWrt installation guide (use OpenWrt
   initramfs-recovery.itb instead of initramfs-kernel.bin at the step 10,
   12 and 14).
Link: https://openwrt.org/toh/mercusys/mr90x_v1#installation

2. Make backups:
```
cat /dev/mtd0 > /tmp/boot.bin
cat /dev/mtd5 > /tmp/tp_data.bin
```
   Copy /tp_data dir content, /tmp/boot.bin and /tmp/tp_data.bin and to
   your PC using scp. You can also backup the remaining partititons. Copy
   backups to a safe place, they are required for the next steps and stock
   firmware recovery.

3. Reboot to OpenWrt initramfs:
```
reboot
```

4. Copy OpenWrt ubi-bl31-uboot.fip, ubi-preloader.bin,
   ubi-squashfs-sysupgrade.itb and MT7986_EEPROM.bin, default-mac (from
   /tp_data backup) to the /tmp folder of the router using scp.

5. Prepare UBI:
```
ubidetach -p /dev/mtd3; ubiformat /dev/mtd3 -y; ubiattach -p /dev/mtd3
ubimkvol /dev/ubi0 -N fip -t static -s 1MiB
ubiupdatevol /dev/ubi0_0 /tmp/ubi-bl31-uboot.fip
ubimkvol /dev/ubi0 -N ubootenv -s 0x1f000
ubimkvol /dev/ubi0 -N ubootenv2 -s 0x1f000
```

6.  Install kmod-mtd-rw and unlock partitions:
```
opkg update && opkg install kmod-mtd-rw
insmod mtd-rw i_want_a_brick=1
mtd unlock boot
mtd unlock bl2
mtd unlock factory
```

7. Prepare "factory" partition:
```
dd if=/dev/zero bs=$((0x8000)) count=1 | tr '\000' '\377' > /tmp/factory.bin
dd if=/tmp/MT7986_EEPROM.bin of=/tmp/factory.bin conv=notrunc
dd if=/tmp/default-mac >> /tmp/factory.bin
```

8. Write "factory" partition:
```
mtd erase factory
mtd write /tmp/factory.bin factory
```

9. Write preloader partition:
```
mtd erase bl2
mtd write /tmp/ubi-preloader.bin bl2
```

10. Write OpenWrt sysupgrade image:
```
sysupgrade -n /tmp/ubi-squashfs-sysupgrade.itb
```

Recovery
--------
1. Place OpenWrt initramfs-recovery.itb image (with original name) on the
   tftp server (IP: 192.168.1.254).
2. Press "reset" button and power on the router. After ~10 sec release the
   button.
3. Use OpenWrt initramfs system for recovery.

BL2 and FIP recovery
--------------------
Use mtk_uartboot and UART connetion if BL2 or FIP in UBI is destroyed:
Link: https://github.com/981213/mtk_uartboot
Link: https://openwrt.org/toh/mercusys/mr90x_v1#serial

Return to stock:
----------------
1. Copy "boot" partition backup (boot.bin) to the /tmp dir of the router
   using scp.

2. Install kmod-mtd-rw:
```
opkg update && opkg install kmod-mtd-rw
```

3. Restore stock U-Boot:
```
   insmod mtd-rw i_want_a_brick=1
   mtd unlock boot
   mtd erase boot
   mtd write /tmp/boot.bin boot
```

4. Erase UBI and reboot:
```
mtd erase ubi
reboot
```

5. Open U-Boot web recovery, upload stock firmware image and start
   upgrade.
Link: http://192.168.1.1

6. Complete steps 1-9 of the OpenWrt installation guide to get root
   rights.
Link: https://openwrt.org/toh/mercusys/mr90x_v1#installation

7. Upload "tp_data" partition backup (tp_data.bin) to the /tmp folder of
   the router using scp.

8. Restore stock calibrations:
```
mtd write /tmp/tp_data.bin tp_data
reboot
```

9. Perform "factory restore" via stock firmware web interface.

Signed-off-by: Mikhail Zhilkin <csharper2005@gmail.com>
Link: openwrt/openwrt#16744
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

Author: csharper2005

package/boot/uboot-envtools/files/mediatek_filogic

@@ -36,6 +36,7 @@ case "$board" in
 abt,asr3000|\
 h3c,magic-nx30-pro|\
 jcg,q30-pro|\
+mercusys,mr90x-v1-ubi|\
 netcore,n60|\
 nokia,ea0326gmp|\
 qihoo,360t7|\

target/linux/mediatek/dts/mt7986b-mercusys-mr90x-v1-common.dtsi

@@ -0,0 +1,252 @@
+// SPDX-License-Identifier: (GL-2.0 OR MIT)
+
+/dts-v1/;
+#include <dt-bindings/input/input.h>
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/leds/common.h>
+
+#include "mt7986b.dtsi"
+
+/ {
+	aliases: aliases {
+		led-boot = &led_status_green;
+		led-failsafe = &led_status_green;
+		led-running = &led_status_green;
+		led-upgrade = &led_status_green;
+
+		serial0 = &uart0;
+	};
+
+	chosen: chosen {
+		stdout-path = "serial0:115200n8";
+	};
+
+	memory {
+		reg = <0 0x40000000 0 0x20000000>;
+	};
+
+	keys {
+		compatible = "gpio-keys";
+
+		reset {
+			label = "reset";
+			gpios = <&pio 10 GPIO_ACTIVE_LOW>;
+			linux,code = <KEY_RESTART>;
+		};
+	};
+
+	leds {
+		compatible = "gpio-leds";
+
+		led-0 {
+			color = <LED_COLOR_ID_GREEN>;
+			function = LED_FUNCTION_LAN;
+			function-enumerator = <2>;
+			gpios = <&pio 7 GPIO_ACTIVE_LOW>;
+		};
+
+		led-1 {
+			color = <LED_COLOR_ID_GREEN>;
+			function = LED_FUNCTION_LAN;
+			function-enumerator = <1>;
+			gpios = <&pio 9 GPIO_ACTIVE_LOW>;
+		};
+
+		led-2 {
+			color = <LED_COLOR_ID_GREEN>;
+			function = LED_FUNCTION_LAN;
+			function-enumerator = <0>;
+			gpios = <&pio 12 GPIO_ACTIVE_LOW>;
+		};
+
+		led-3 {
+			color = <LED_COLOR_ID_GREEN>;
+			function = LED_FUNCTION_WAN;
+			gpios = <&pio 13 GPIO_ACTIVE_LOW>;
+		};
+
+		led-4 {
+			color = <LED_COLOR_ID_AMBER>;
+			function = LED_FUNCTION_STATUS;
+			gpios = <&pio 16 GPIO_ACTIVE_HIGH>;
+			panic-indicator;
+		};
+
+		led_status_green: led-5 {
+			color = <LED_COLOR_ID_GREEN>;
+			function = LED_FUNCTION_STATUS;
+			gpios = <&pio 17 GPIO_ACTIVE_HIGH>;
+		};
+	};
+};
+
+&crypto {
+	status = "okay";
+};
+
+&eth {
+	status = "okay";
+
+	gmac0: mac@0 {
+		compatible = "mediatek,eth-mac";
+		reg = <0>;
+		phy-mode = "2500base-x";
+
+		fixed-link {
+			speed = <2500>;
+			full-duplex;
+			pause;
+		};
+	};
+
+	gmac1: mac@1 {
+		compatible = "mediatek,eth-mac";
+		reg = <1>;
+		phy-handle = <&phy6>;
+		phy-mode = "2500base-x";
+	};
+
+	mdio: mdio-bus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+	};
+};
+
+&mdio {
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	reset-gpios = <&pio 6 GPIO_ACTIVE_LOW>;
+	reset-delay-us = <1500000>;
+	reset-post-delay-us = <1000000>;
+
+	/* WAN/LAN 2.5Gbps phy
+	   MaxLinear GPY211C0VC (SLNW8) */
+	phy6: phy@6 {
+		compatible = "ethernet-phy-ieee802.3-c45";
+		reg = <6>;
+	};
+
+	switch: switch@1f {
+		compatible = "mediatek,mt7531";
+		reg = <31>;
+		reset-gpios = <&pio 5 GPIO_ACTIVE_HIGH>;
+	};
+};
+
+&switch {
+	ports {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		/* WAN/LAN 1Gbps port */
+		port@0 {
+			reg = <0>;
+			label = "lan0";
+		};
+
+		/* LAN1 port */
+		port@1 {
+			reg = <1>;
+			label = "lan1";
+		};
+
+		/* LAN2 port */
+		port@2 {
+			reg = <2>;
+			label = "lan2";
+		};
+
+		port@6 {
+			reg = <6>;
+			ethernet = <&gmac0>;
+			phy-mode = "2500base-x";
+
+			fixed-link {
+				speed = <2500>;
+				full-duplex;
+				pause;
+			};
+		};
+	};
+};
+
+&pio {
+	spi_flash_pins: spi-flash-pins-33-to-38 {
+		mux {
+			function = "spi";
+			groups = "spi0", "spi0_wp_hold";
+		};
+		conf-pu {
+			pins = "SPI2_CS", "SPI2_HOLD", "SPI2_WP";
+			drive-strength = <8>;
+			mediatek,pull-up-adv = <0>; /* bias-disable */
+		};
+		conf-pd {
+			pins = "SPI2_CLK", "SPI2_MOSI", "SPI2_MISO";
+			drive-strength = <8>;
+			mediatek,pull-down-adv = <0>; /* bias-disable */
+		};
+	};
+
+	wf_2g_5g_pins: wf_2g_5g-pins {
+		mux {
+			function = "wifi";
+			groups = "wf_2g", "wf_5g";
+		};
+		conf {
+			pins = "WF0_HB1", "WF0_HB2", "WF0_HB3", "WF0_HB4",
+			       "WF0_HB0", "WF0_HB0_B", "WF0_HB5", "WF0_HB6",
+			       "WF0_HB7", "WF0_HB8", "WF0_HB9", "WF0_HB10",
+			       "WF0_TOP_CLK", "WF0_TOP_DATA", "WF1_HB1",
+			       "WF1_HB2", "WF1_HB3", "WF1_HB4", "WF1_HB0",
+			       "WF1_HB5", "WF1_HB6", "WF1_HB7", "WF1_HB8",
+			       "WF1_TOP_CLK", "WF1_TOP_DATA";
+			drive-strength = <4>;
+		};
+	};
+};
+
+&spi0 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&spi_flash_pins>;
+	status = "okay";
+
+	spi_nand_flash: flash@0 {
+		compatible = "spi-nand";
+		#address-cells = <1>;
+		#size-cells = <1>;
+		reg = <0>;
+
+		spi-max-frequency = <20000000>;
+		spi-tx-bus-width = <4>;
+		spi-rx-bus-width = <4>;
+
+		partitions: partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+		};
+	};
+};
+
+&trng {
+	status = "okay";
+};
+
+&uart0 {
+	status = "okay";
+};
+
+&watchdog {
+	status = "okay";
+};
+
+&wifi {
+	status = "okay";
+
+	pinctrl-names = "default";
+	pinctrl-0 = <&wf_2g_5g_pins>;
+
+	ieee80211-freq-limit = <2400000 2500000>, <5170000 5835000>;
+};

target/linux/mediatek/dts/mt7986b-mercusys-mr90x-v1-ubi.dts

@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: (GL-2.0 OR MIT)
+
+#include "mt7986b-mercusys-mr90x-v1-common.dtsi"
+
+/ {
+	compatible = "mercusys,mr90x-v1-ubi", "mediatek,mt7986b";
+	model = "MERCUSYS MR90X v1 (UBI)";
+};
+
+&aliases {
+	label-mac-device = &gmac0;
+};
+
+&chosen {
+	bootargs-append = " root=/dev/fit0 rootwait";
+	rootdisk = <&ubi_fit>;
+};
+
+&gmac0 {
+	nvmem-cells = <&macaddr_factory_8000 0>;
+	nvmem-cell-names = "mac-address";
+};
+
+&gmac1 {
+	nvmem-cells = <&macaddr_factory_8000 1>;
+	nvmem-cell-names = "mac-address";
+};
+
+&partitions {
+	partition@0 {
+		label = "boot";
+		reg = <0x0 0x200000>;
+		read-only;
+
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		partition@0 {
+			label = "bl2";
+			reg = <0x0 0x100000>;
+			read-only;
+		};
+
+		partition@100000 {
+			label = "factory";
+			reg = <0x100000 0x100000>;
+			read-only;
+
+			nvmem-layout {
+				compatible = "fixed-layout";
+				#address-cells = <1>;
+				#size-cells = <1>;
+
+				eeprom_factory_0: eeprom@0 {
+					reg = <0x0 0x1000>;
+				};
+
+				macaddr_factory_8000: macaddr@8000 {
+					compatible = "mac-base";
+					reg = <0x8000 0x6>;
+					#nvmem-cell-cells = <1>;
+				};
+			};
+		};
+	};
+
+	partition@200000 {
+		compatible = "linux,ubi";
+		reg = <0x200000 0x7e00000>;
+		label = "ubi";
+
+		volumes {
+			ubi_fit: ubi-volume-fit {
+				volname = "fit";
+			};
+
+			ubi_ubootenv: ubi-volume-ubootenv {
+				volname = "ubootenv";
+			};
+
+			ubi_ubootenv2: ubi-volume-ubootenv2 {
+				volname = "ubootenv2";
+			};
+		};
+	};
+};
+
+&trng {
+	status = "okay";
+};
+
+&uart0 {
+	status = "okay";
+};
+
+&ubi_ubootenv {
+	nvmem-layout {
+		compatible = "u-boot,env-redundant-bool";
+	};
+};
+
+&ubi_ubootenv2 {
+	nvmem-layout {
+		compatible = "u-boot,env-redundant-bool";
+	};
+};
+
+&wifi {
+	nvmem-cells = <&eeprom_factory_0>;
+	nvmem-cell-names = "eeprom";
+
+	band@0 {
+		reg = <0>;
+		nvmem-cells = <&macaddr_factory_8000 0>;
+		nvmem-cell-names = "mac-address";
+	};
+
+	band@1 {
+		reg = <1>;
+		nvmem-cells = <&macaddr_factory_8000 (-1)>;
+		nvmem-cell-names = "mac-address";
+	};
+};