arm: mediatek: add support for MediaTek MT8188 SoC

This adds basic support for MediaTek MT8188 SoC.

Add watchdog support by adding upstream compatible string.

Add tphy support by adding "mediatek,generic-tphy-v2" compatible string
in arch/arm/dts/mt8188-u-boot.dtsi

Signed-off-by: Julien Masson <jmasson@baylibre.com>
Signed-off-by: Julien Stephan <jstephan@baylibre.com>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
Reviewed-by: Macpaul Lin <macpaul.lin@mediatek.com>

arch/arm/dts/mt8188-u-boot.dtsi

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/*
+ * Copyright (c) 2025 Baylibre SAS.
+ * Author: Julien Masson <jmasson@baylibre.com>
+ */
+
+&u3phy0 {
+	compatible = "mediatek,mt8188-tphy", "mediatek,generic-tphy-v3",
+		     "mediatek,generic-tphy-v2";
+};

arch/arm/mach-mediatek/Kconfig

@@ -84,6 +84,15 @@ config TARGET_MT8183
 	  SD and MMC cards, UFS, PWM, I2C, I2S, S/PDIF, and several LPDDR3
 	  and LPDDR4 options.
 
+config TARGET_MT8188
+	bool "MediaTek MT8188 SoC"
+	select ARM64
+	help
+	  The MediaTek MT8188 is a ARM64-based SoC with a dual-core Cortex-A78
+          cluster and a six-core Cortex-A55 cluster. It includes UART, SPI,
+          USB3.0 dual role, SD and MMC cards, UFS, PWM, I2C, I2S, S/PDIF, and
+          several LPDDR3 and LPDDR4 options.
+
 config TARGET_MT8365
 	bool "MediaTek MT8365 SoC"
 	select ARM64
@@ -157,7 +166,7 @@ config SYS_CONFIG_NAME
 config MTK_BROM_HEADER_INFO
 	string
 	default "media=nor" if TARGET_MT8518 || TARGET_MT8512 || TARGET_MT7629
-	default "media=emmc" if TARGET_MT8516 || TARGET_MT8365 || TARGET_MT8183
+	default "media=emmc" if TARGET_MT8516 || TARGET_MT8365 || TARGET_MT8183 || TARGET_MT8188
 	default "lk=1" if TARGET_MT7623
 
 config MTK_TZ_MOVABLE

arch/arm/mach-mediatek/Makefile

@@ -12,6 +12,7 @@ obj-$(CONFIG_TARGET_MT7986) += mt7986/
 obj-$(CONFIG_TARGET_MT7987) += mt7987/
 obj-$(CONFIG_TARGET_MT7988) += mt7988/
 obj-$(CONFIG_TARGET_MT8183) += mt8183/
+obj-$(CONFIG_TARGET_MT8188) += mt8188/
 obj-$(CONFIG_TARGET_MT8365) += mt8365/
 obj-$(CONFIG_TARGET_MT8512) += mt8512/
 obj-$(CONFIG_TARGET_MT8516) += mt8516/

arch/arm/mach-mediatek/mt8188/Makefile

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier:	GPL-2.0
+
+obj-y += init.o

arch/arm/mach-mediatek/mt8188/init.c

@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2025 MediaTek Inc.
+ * Copyright (C) 2025 BayLibre, SAS
+ * Author: Julien Masson <jmasson@baylibre.com>
+ *         Chris-QJ Chen <chris-qj.chen@mediatek.com>
+ */
+
+#include <asm/global_data.h>
+#include <asm/system.h>
+#include <dm/uclass.h>
+#include <linux/sizes.h>
+#include <wdt.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int dram_init(void)
+{
+	int ret;
+
+	ret = fdtdec_setup_memory_banksize();
+	if (ret)
+		return ret;
+
+	fdtdec_setup_mem_size_base();
+
+	/*
+	 * Limit gd->ram_top not exceeding SZ_4G.  Some periphals like mmc
+	 * requires DMA buffer allocated below SZ_4G.
+	 *
+	 * Note: SZ_1M is for adjusting gd->relocaddr, the reserved memory for
+	 * u-boot itself.
+	 */
+	if (gd->ram_base + gd->ram_size >= SZ_4G)
+		gd->mon_len = (gd->ram_base + gd->ram_size + SZ_1M) - SZ_4G;
+
+	return 0;
+}
+
+int dram_init_banksize(void)
+{
+	gd->bd->bi_dram[0].start = gd->ram_base;
+	gd->bd->bi_dram[0].size = gd->ram_size;
+
+	return 0;
+}
+
+int mtk_soc_early_init(void)
+{
+	return 0;
+}
+
+void reset_cpu(void)
+{
+	struct udevice *wdt;
+
+	if (IS_ENABLED(CONFIG_PSCI_RESET)) {
+		psci_system_reset();
+	} else {
+		uclass_first_device(UCLASS_WDT, &wdt);
+		if (wdt)
+			wdt_expire_now(wdt, 0);
+	}
+}
+
+int print_cpuinfo(void)
+{
+	printf("CPU:   MediaTek MT8188\n");
+	return 0;
+}