mips: mtmips: add support for mt7628-rfb

This patch adds support for mt7628 reference board. SPL_DM and DT are not
enabled for SPL to save about 17KiB for u-boot-spl.bin.

Reviewed-by: Stefan Roese <sr@denx.de>
Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
diff --git a/include/configs/mt7628.h b/include/configs/mt7628.h
new file mode 100644
index 0000000..9b9218d
--- /dev/null
+++ b/include/configs/mt7628.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020 MediaTek Inc.
+ *
+ * Author: Weijie Gao <weijie.gao@mediatek.com>
+ */
+
+#ifndef __CONFIG_MT7628_H
+#define __CONFIG_MT7628_H
+
+#define CONFIG_SYS_HZ			1000
+#define CONFIG_SYS_MIPS_TIMER_FREQ	290000000
+
+#define CONFIG_SYS_MONITOR_BASE		CONFIG_SYS_TEXT_BASE
+
+#define CONFIG_SYS_MALLOC_LEN		0x100000
+#define CONFIG_SYS_BOOTPARAMS_LEN	0x20000
+
+#define CONFIG_SYS_SDRAM_BASE		0x80000000
+#define CONFIG_SYS_LOAD_ADDR		0x80010000
+
+#define CONFIG_SYS_INIT_SP_OFFSET	0x80000
+
+#define CONFIG_SYS_BOOTM_LEN		0x1000000
+
+#define CONFIG_SYS_MAXARGS		16
+#define CONFIG_SYS_CBSIZE		1024
+
+/* Serial SPL */
+#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_SERIAL_SUPPORT)
+#define CONFIG_SYS_NS16550_MEM32
+#define CONFIG_SYS_NS16550_CLK		40000000
+#define CONFIG_SYS_NS16550_REG_SIZE	-4
+#define CONFIG_SYS_NS16550_COM1		0xb0000c00
+#define CONFIG_CONS_INDEX		1
+#endif
+
+/* Serial common */
+#define CONFIG_SYS_BAUDRATE_TABLE	{ 9600, 19200, 38400, 57600, 115200, \
+					  230400, 460800, 921600 }
+
+/* SPL */
+#if defined(CONFIG_SPL) && !defined(CONFIG_SPL_BUILD)
+#define CONFIG_SKIP_LOWLEVEL_INIT
+#endif
+
+#define CONFIG_SYS_UBOOT_START		CONFIG_SYS_TEXT_BASE
+#define CONFIG_SPL_BSS_START_ADDR	0x80010000
+#define CONFIG_SPL_BSS_MAX_SIZE		0x10000
+#define CONFIG_SPL_MAX_SIZE		0x10000
+#define CONFIG_SPL_PAD_TO		0
+
+/* Dummy value */
+#define CONFIG_SYS_UBOOT_BASE		0
+
+#endif /* __CONFIG_MT7628_H */