arm: MediaTek: add basic support for MT7623 boards

This adds a general board file based on MT7623 SoCs from MediaTek.

As this u-boot is loaded by MTK proprietary preloader, there is no
low level initializtion codes.

Tested-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-mediatek/Kconfig b/arch/arm/mach-mediatek/Kconfig
index d2ada97..7a733e9 100644
--- a/arch/arm/mach-mediatek/Kconfig
+++ b/arch/arm/mach-mediatek/Kconfig
@@ -9,6 +9,18 @@
 choice
 	prompt "MediaTek board select"
 
+config TARGET_MT7623
+	bool "MediaTek MT7623 SoC"
+	select CPU_V7A
+	select ARCH_MISC_INIT
+	help
+	  The MediaTek MT7623 is a ARM-based SoC with a quad-core Cortex-A7
+	  including NEON and GPU, Mali-450 graphics, several DDR3 options,
+	  crypto engine, built-in Wi-Fi / Bluetooth combo chip, JPEG decoder,
+	  video interfaces supporting HDMI and MIPI, and video codec support.
+	  Peripherals include Gigabit Ethernet, switch, USB3.0 and OTG, PCIe,
+	  I2S, PCM, S/PDIF, UART, SPI, I2C, IR TX/RX, and PWM.
+
 config TARGET_MT7629
 	bool "MediaTek MT7629 SoC"
 	select CPU_V7A
@@ -21,6 +33,7 @@
 
 endchoice
 
+source "board/mediatek/mt7623/Kconfig"
 source "board/mediatek/mt7629/Kconfig"
 
 endif
diff --git a/arch/arm/mach-mediatek/Makefile b/arch/arm/mach-mediatek/Makefile
index 852d330..b5d3a37 100644
--- a/arch/arm/mach-mediatek/Makefile
+++ b/arch/arm/mach-mediatek/Makefile
@@ -3,4 +3,5 @@
 obj-y	+= cpu.o
 obj-$(CONFIG_SPL_BUILD)	+= spl.o
 
+obj-$(CONFIG_TARGET_MT7623) += mt7623/
 obj-$(CONFIG_TARGET_MT7629) += mt7629/
diff --git a/arch/arm/mach-mediatek/mt7623/Makefile b/arch/arm/mach-mediatek/mt7623/Makefile
new file mode 100644
index 0000000..007eb4a
--- /dev/null
+++ b/arch/arm/mach-mediatek/mt7623/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier:	GPL-2.0
+
+obj-y += init.o
+obj-y += lowlevel_init.o
diff --git a/arch/arm/mach-mediatek/mt7623/init.c b/arch/arm/mach-mediatek/mt7623/init.c
new file mode 100644
index 0000000..0ee8c66
--- /dev/null
+++ b/arch/arm/mach-mediatek/mt7623/init.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 MediaTek Inc.
+ */
+
+#include <common.h>
+#include <linux/io.h>
+#include <linux/sizes.h>
+#include <asm/arch/misc.h>
+
+#include "preloader.h"
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct boot_argument *preloader_param;
+
+int mtk_soc_early_init(void)
+{
+	return 0;
+}
+
+int dram_init(void)
+{
+	u32 i;
+
+	if (((size_t)preloader_param >= CONFIG_SYS_SDRAM_BASE) &&
+	    ((size_t)preloader_param % sizeof(size_t) == 0) &&
+	    preloader_param->magic == BOOT_ARGUMENT_MAGIC &&
+	    preloader_param->dram_rank_num <=
+	    ARRAY_SIZE(preloader_param->dram_rank_size)) {
+		gd->ram_size = 0;
+
+		for (i = 0; i < preloader_param->dram_rank_num; i++)
+			gd->ram_size += preloader_param->dram_rank_size[i];
+	} else {
+		gd->ram_size = get_ram_size((long *)CONFIG_SYS_SDRAM_BASE,
+					    SZ_2G);
+	}
+
+	return 0;
+}
+
+int print_cpuinfo(void)
+{
+	void __iomem *chipid;
+	u32 swver;
+
+	chipid = ioremap(VER_BASE, VER_SIZE);
+	swver = readl(chipid + APSW_VER);
+
+	printf("CPU:   MediaTek MT7623 E%d\n", (swver & 0xf) + 1);
+
+	return 0;
+}
diff --git a/arch/arm/mach-mediatek/mt7623/lowlevel_init.S b/arch/arm/mach-mediatek/mt7623/lowlevel_init.S
new file mode 100644
index 0000000..afb9476
--- /dev/null
+++ b/arch/arm/mach-mediatek/mt7623/lowlevel_init.S
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2018 MediaTek Inc.
+ */
+
+#include <linux/linkage.h>
+
+.extern	preloader_param
+
+ENTRY(save_boot_params)
+	ldr	r6, =preloader_param
+	str	r4, [r6]
+	b	save_boot_params_ret
+ENDPROC(save_boot_params)
+
+ENTRY(lowlevel_init)
+	/* enable SMP bit */
+	mrc	p15, 0, r0, c1, c0, 1
+	orr	r0, r0, #0x40
+	mcr	p15, 0, r0, c1, c0, 1
+	mov	pc, lr
+ENDPROC(lowlevel_init)
diff --git a/arch/arm/mach-mediatek/mt7623/preloader.h b/arch/arm/mach-mediatek/mt7623/preloader.h
new file mode 100644
index 0000000..2d2c71a
--- /dev/null
+++ b/arch/arm/mach-mediatek/mt7623/preloader.h
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2018 MediaTek Inc.
+ */
+
+#ifndef __PRELOADER_H_
+#define __PRELOADER_H_
+
+enum forbidden_mode {
+	F_FACTORY_MODE = 0x0001
+};
+
+union lk_hdr {
+	struct {
+		u32 magic;
+		u32 size;
+		char name[32];
+		u32 loadaddr;
+	};
+
+	u8 data[512];
+};
+
+struct sec_limit {
+	unsigned int magic_num;
+	enum forbidden_mode forbid_mode;
+};
+
+enum bootmode {
+	NORMAL_BOOT = 0,
+	META_BOOT = 1,
+	RECOVERY_BOOT = 2,
+	SW_REBOOT = 3,
+	FACTORY_BOOT = 4,
+	ADVMETA_BOOT = 5,
+	ATE_FACTORY_BOOT = 6,
+	ALARM_BOOT = 7,
+
+	KERNEL_POWER_OFF_CHARGING_BOOT = 8,
+	LOW_POWER_OFF_CHARGING_BOOT = 9,
+
+	FAST_BOOT = 99,
+	DOWNLOAD_BOOT = 100,
+	UNKNOWN_BOOT
+};
+
+enum boot_reason {
+	BR_POWER_KEY = 0,
+	BR_USB,
+	BR_RTC,
+	BR_WDT,
+	BR_WDT_BY_PASS_PWK,
+	BR_TOOL_BY_PASS_PWK,
+	BR_2SEC_REBOOT,
+	BR_UNKNOWN
+};
+
+enum meta_com_type {
+	META_UNKNOWN_COM = 0,
+	META_UART_COM,
+	META_USB_COM
+};
+
+struct da_info_t {
+	u32 addr;
+	u32 arg1;
+	u32 arg2;
+	u32 len;
+	u32 sig_len;
+};
+
+struct boot_argument {
+	u32 magic;
+	enum bootmode boot_mode;
+	u32 e_flag;
+	u32 log_port;
+	u32 log_baudrate;
+	u8 log_enable;
+	u8 part_num;
+	u8 reserved[2];
+	u32 dram_rank_num;
+	u32 dram_rank_size[4];
+	u32 boot_reason;
+	enum meta_com_type meta_com_type;
+	u32 meta_com_id;
+	u32 boot_time;
+	struct da_info_t da_info;
+	struct sec_limit sec_limit;
+	union lk_hdr *part_info;
+	u8 md_type[4];
+	u32 ddr_reserve_enable;
+	u32 ddr_reserve_success;
+	u32 chip_ver;
+	char pl_version[8];
+};
+
+#define BOOT_ARGUMENT_MAGIC	0x504c504c
+
+#endif /* __PRELOADER_H_ */