Support to build 32 bits version.

arch/arm/dts/mt7622.dtsi

@@ -139,6 +139,11 @@
 		reg = <0x10212000 0x800>;
 	};
 
+	wdt-reboot {
+		compatible = "wdt-reboot";
+		wdt = <&watchdog>;
+	};
+
 	gic: interrupt-controller@10300000 {
 		compatible = "arm,gic-400";
 		interrupt-controller;

arch/arm/mach-mediatek/Kconfig

@@ -6,12 +6,17 @@ config SYS_SOC
 config SYS_VENDOR
 	default "mediatek"
 
+config ARCH_MEDIATEK_32
+	bool "Build 32 bits version"
+	default n
+
 choice
 	prompt "MediaTek board select"
 
 config TARGET_MT7622
 	bool "MediaTek MT7622 SoC"
-	select ARM64
+	select CPU_V7A if ARCH_MEDIATEK_32
+	select ARM64 if !ARCH_MEDIATEK_32
 	help
 	  The MediaTek MT7622 is a ARM64-based SoC with a dual-core Cortex-A53.
 	  including UART, SPI, USB3.0, SD and MMC cards, NAND, SNFI, PWM, PCIe,

arch/arm/mach-mediatek/mt7622/init.c

@@ -6,7 +6,9 @@
 
 #include <common.h>
 #include <fdtdec.h>
+#ifdef CONFIG_ARM64
 #include <asm/armv8/mmu.h>
+#endif
 
 int print_cpuinfo(void)
 {
@@ -25,6 +27,7 @@ int dram_init(void)
 
 }
 
+#ifdef CONFIG_ARM64
 void reset_cpu(ulong addr)
 {
 	psci_system_reset();
@@ -49,3 +52,4 @@ static struct mm_region mt7622_mem_map[] = {
 	}
 };
 struct mm_region *mem_map = mt7622_mem_map;
+#endif

configs/mt7622_rfb_32_defconfig

@@ -0,0 +1,57 @@
+CONFIG_ARM=y
+CONFIG_POSITION_INDEPENDENT=y
+CONFIG_ARCH_MEDIATEK=y
+CONFIG_ARCH_MEDIATEK_32=y
+CONFIG_TARGET_MT7622=y
+CONFIG_SYS_TEXT_BASE=0x41e00000
+CONFIG_SYS_MALLOC_F_LEN=0x4000
+CONFIG_NR_DRAM_BANKS=1
+CONFIG_SMBIOS_PRODUCT_NAME=""
+CONFIG_FIT=y
+CONFIG_LOGLEVEL=7
+CONFIG_LOG=y
+CONFIG_LOG_MAX_LEVEL=6
+CONFIG_DEFAULT_FDT_FILE="mt7622-rfb"
+CONFIG_SYS_PROMPT="MT7622> "
+CONFIG_CMD_BOOTMENU=y
+CONFIG_CMD_MMC=y
+CONFIG_CMD_SF_TEST=y
+CONFIG_CMD_SMC=y
+CONFIG_DEFAULT_DEVICE_TREE="mt7622-rfb"
+CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG=y
+CONFIG_REGMAP=y
+CONFIG_SYSCON=y
+CONFIG_CLK=y
+CONFIG_DM_GPIO=y
+CONFIG_DM_MMC=y
+CONFIG_MMC_HS200_SUPPORT=y
+CONFIG_MMC_MTK=y
+CONFIG_DM_SPI_FLASH=y
+CONFIG_SPI_FLASH_EON=y
+CONFIG_SPI_FLASH_GIGADEVICE=y
+CONFIG_SPI_FLASH_ISSI=y
+CONFIG_SPI_FLASH_MACRONIX=y
+CONFIG_SPI_FLASH_SPANSION=y
+CONFIG_SPI_FLASH_STMICRO=y
+CONFIG_SPI_FLASH_WINBOND=y
+CONFIG_DM_ETH=y
+CONFIG_PINCTRL=y
+CONFIG_PINCONF=y
+CONFIG_PINCTRL_MT7622=y
+CONFIG_POWER_DOMAIN=y
+CONFIG_MTK_POWER_DOMAIN=y
+CONFIG_RAM=y
+CONFIG_DM_RESET=y
+CONFIG_DM_SERIAL=y
+CONFIG_MTK_SERIAL=y
+CONFIG_SPI=y
+CONFIG_DM_SPI=y
+CONFIG_MTK_SNFI_SPI=y
+CONFIG_SYSRESET=y
+CONFIG_SYSRESET_WATCHDOG=y
+CONFIG_TIMER=y
+CONFIG_MTK_TIMER=y
+CONFIG_WDT_MTK=y
+CONFIG_LZ4=y
+CONFIG_LZO=y
+CONFIG_HEXDUMP=y