In order to build a kernel with one of these configs the user should do

the following:

1. Give the appropriate board dts file to be used by either:
1.1. edit the SoC kernel config required (e.g., MT7620A_FDT) and include
the required FDT_DTS_FILE makeoption; or
1.2. simply supply FDT_DTS_FILE="xx.dts" on the command line when building
the kernel
Of course, the user can also create a completely new kernel config to
match the desired board and include the SoC kernel config from within
it.

If required, edit the MEDIATEK config file, which includes optional
drivers and comment out the unneeded ones.
2.1. this would only make sense if kernel size is a concern. Even if we
build the kernel with all drivers, if we lzma it and package it as a uImage,
its size is still around 1.1MiB.

The user will have to choose a dts file (or create a new one) from
sys/gnu/dts/mips , where all Mediatek/Ralink dts files will be imported via
a later revision.

Approved by:	adrian (mentor)
Sponsored by:	Smartcom - Bulgaria AD
Differential Revision:	https://reviews.freebsd.org/D5966

sys/mips/conf/MEDIATEK

@@ -0,0 +1,81 @@
+#
+# MEDIATEK -- Kernel configuration file for FreeBSD/MIPS Mediatek/Ralink SoCs
+#
+# This includes all the configurable parts of the kernel. Please read through
+# the sections below and customize the options to fit your board if needed.
+#
+# $FreeBSD$
+#
+
+#NO_UNIVERSE
+
+# Don't build any modules by default
+makeoptions 	MODULES_OVERRIDE=""
+
+#
+# Default rootfs device configuration, should be changed to suit target board
+#
+options 	ROOTDEVNAME=\"ufs:md0.uzip\"
+
+#
+# Optional drivers section
+#
+# What follows is optional support drivers for the Mediatek SoCs.
+# The kernel can be compiled without them if size is a concern.
+# All optional drivers are built by default.
+#
+
+# Support geom_uzip(4) compressed disk images
+device 		geom_uzip
+options 	GEOM_UZIP
+
+# Support md(4) and md-based rootfs
+device 		md
+options 	MD_ROOT
+
+# SPI and SPI flash support
+device 		spibus
+device 		mx25l
+
+# GPIO and gpioled support
+device 		gpio
+device 		gpioled
+
+# PCI support
+device 		pci
+
+#
+# USB (ehci, ohci, xhci, otg) support. Unneeded drivers can be commented in
+# order to lower kernel size. See below for driver SoC support.
+#
+# For all SoCs that require USB support
+device 		usb
+# For RT3050, RT3052 and RT3350 SoCs
+device 		dwcotg
+# For RT3352, RT3662, RT3883, RT5350, MT7620, MT7628 and MT7688
+device 		ohci
+device 		ehci
+# For MT7621, or cases where the target board has a XHCI controller on PCI
+# (for example Asus RT-N65U)
+device 		xhci
+
+# USB umass(4) storage and da(4) support
+device 		umass
+device 		da
+
+# ahci(4) and ada(4) support, depends on PCI
+device 		ahci
+device 		ada
+
+# CAM support, required if either umass(4) or ahci(4) is enabled above
+device 		pass
+device 		scbus
+
+# Ethernet, BPS and bridge support
+device 		rt
+device 		bpf
+device 		if_bridge
+
+# Extres
+device 		ext_resources
+device 		clk

sys/mips/conf/MEDIATEK_BASE

@@ -0,0 +1,89 @@
+#
+# MEDIATEK_BASE -- Base kernel configuration file for FreeBSD/MIPS
+# Mediatek/Ralink SoCs.
+#
+# This includes all the required drivers for the SoCs.
+# Ususally, users should not build this kernel configuration. It is provided
+# only as a minimum base, from which customizations can be made. Please look
+# at MEDIATEK kernel configuration for customization details.
+#
+# $FreeBSD$
+#
+
+#NO_UNIVERSE
+
+# Include the standard file list for Mediatek SoCs.
+files 		"../mediatek/files.mtk"
+
+# Building a mips/mipsel kernel
+machine 	mips mipsel
+
+# Little-endian machine
+makeoptions 	MIPS_LITTLE_ENDIAN=defined
+
+# Default kernel load address
+makeoptions 	KERNLOADADDR=0x80001000
+
+# Mediatek/Ralink SoC support depends on FDT (with static DTB for the moment)
+options 	FDT
+options 	FDT_DTB_STATIC
+
+# We rely on MIPS_INTRNG code
+options 	MIPS_INTRNG
+options 	MIPS_NIRQ=256
+
+# We rely on NEW_PCIB code
+options 	NEW_PCIB
+
+# Build kernel with gdb(1) debug symbols
+makeoptions 	DEBUG=-g
+
+# Support for DDB and KDB
+options 	DDB
+options 	KDB
+
+# Debugging for use in -current
+options 	INVARIANTS
+options 	INVARIANT_SUPPORT
+options 	WITNESS
+options 	WITNESS_SKIPSPIN
+options 	DEBUG_REDZONE
+options 	DEBUG_MEMGUARD
+
+# For small memory footprints
+options 	VM_KMEM_SIZE_SCALE=1
+
+# General options, including scheduler, etc.
+options 	SCHED_ULE	# ULE scheduler
+options 	INET		# InterNETworking
+#options 	INET6		# IPv6
+options 	PSEUDOFS	# Pseude-filesystem framework
+options 	FFS		# Berkeley Fast Filesystem
+#options 	SOFTUPDATES	# Enable FFS soft updates support
+#options 	UFS_ACL		# Support for access control lists
+#options 	UFS_DIRHASH	# Improve big directory performance
+#options 	MSDOSFS		# Enable support for MSDOS filesystems
+options 	_KPOSIX_PRIORITY_SCHEDULING	# Posix P1003_1B real-time ext.
+
+#
+# Standard drivers section
+#
+# The drivers in the following section are required in order to successfully
+# compile the kernel.
+#
+
+# FDT clock and pinctrl framework
+device 		fdt_clock
+device 		fdt_pinctrl
+
+# UART support
+device 		uart
+
+# random support
+device 		random
+
+# loop device support
+device 		loop
+
+# ether device support
+device 		ether

sys/mips/conf/MT7620A_FDT

@@ -0,0 +1,30 @@
+#
+# MT7620A_FDT -- Kernel configuration file for FreeBSD/MIPS MT7620A SoC
+#
+# This includes all the configurable parts of the kernel. Please read through
+# MEDIATEK kernel config and customize the options to fit your board if needed.
+#
+# $FreeBSD$
+#
+
+#NO_UNIVERSE
+
+#
+# FDT_DTS_FILE should be modified to suit the target board type.
+#
+#makeoptions 	FDT_DTS_FILE=MT7620a.dts
+
+#
+# The user should never have to edit what's below this line.
+# If customizations are needed, they should be done to the MEDIATEK kernel
+# configuration.
+#
+
+# Start with a base configuration
+include 	MEDIATEK_BASE
+
+ident 		MT7620A
+cpu 		CPU_MIPS24K
+
+# Include optional configuration (to be edited by the user if needed)
+include 	MEDIATEK

sys/mips/conf/MT7620N_FDT

@@ -0,0 +1,30 @@
+#
+# MT7620N_FDT -- Kernel configuration file for FreeBSD/MIPS MT7620N SoC
+#
+# This includes all the configurable parts of the kernel. Please read through
+# MEDIATEK kernel config and customize the options to fit your board if needed.
+#
+# $FreeBSD$
+#
+
+#NO_UNIVERSE
+
+#
+# FDT_DTS_FILE should be modified to suit the target board type.
+#
+#makeoptions 	FDT_DTS_FILE=WRTNODE.dts
+
+#
+# The user should never have to edit what's below this line.
+# If customizations are needed, they should be done to the MEDIATEK kernel
+# configuration.
+#
+
+# Start with a base configuration
+include 	MEDIATEK_BASE
+
+ident 		MT7620N
+cpu 		CPU_MIPS24K
+
+# Include optional configuration (to be edited by the user if needed)
+include 	MEDIATEK

sys/mips/conf/MT7621_FDT

@@ -0,0 +1,30 @@
+#
+# MT7621_FDT -- Kernel configuration file for FreeBSD/MIPS MT7621 SoC
+#
+# This includes all the configurable parts of the kernel. Please read through
+# MEDIATEK kernel config and customize the options to fit your board if needed.
+#
+# $FreeBSD$
+#
+
+#NO_UNIVERSE
+
+#
+# FDT_DTS_FILE should be modified to suit the target board type.
+#
+#makeoptions 	FDT_DTS_FILE=ZBT-WG2626.dts
+
+#
+# The user should never have to edit what's below this line.
+# If customizations are needed, they should be done to the MEDIATEK kernel
+# configuration.
+#
+
+# Start with a base configuration
+include 	MEDIATEK_BASE
+
+ident 		MT7621
+cpu 		CPU_MIPS1004K
+
+# Include optional configuration (to be edited by the user if needed)
+include 	MEDIATEK

sys/mips/conf/MT7628_FDT

@@ -0,0 +1,30 @@
+#
+# MT7628_FDT -- Kernel configuration file for FreeBSD/MIPS MT7628/MT7688 SoCs
+#
+# This includes all the configurable parts of the kernel. Please read through
+# MEDIATEK kernel config and customize the options to fit your board if needed.
+#
+# $FreeBSD$
+#
+
+#NO_UNIVERSE
+
+#
+# FDT_DTS_FILE should be modified to suit the target board type.
+#
+#makeoptions 	FDT_DTS_FILE=MT7628.dts
+
+#
+# The user should never have to edit what's below this line.
+# If customizations are needed, they should be done to the MEDIATEK kernel
+# configuration.
+#
+
+# Start with a base configuration
+include 	MEDIATEK_BASE
+
+ident 		MT7628
+cpu 		CPU_MIPS24K
+
+# Include optional configuration (to be edited by the user if needed)
+include 	MEDIATEK

sys/mips/conf/RT3050_FDT

@@ -0,0 +1,31 @@
+#
+# RT3050_FDT -- Kernel configuration file for FreeBSD/MIPS RT3050/RT3052/RT3350
+# SoCs
+#
+# This includes all the configurable parts of the kernel. Please read through
+# MEDIATEK kernel config and customize the options to fit your board if needed.
+#
+# $FreeBSD$
+#
+
+#NO_UNIVERSE
+
+#
+# FDT_DTS_FILE should be modified to suit the target board type.
+#
+#makeoptions 	FDT_DTS_FILE=DIR-600-B1.dts
+
+#
+# The user should never have to edit what's below this line.
+# If customizations are needed, they should be done to the MEDIATEK kernel
+# configuration.
+#
+
+# Start with a base configuration
+include 	MEDIATEK_BASE
+
+ident 		RT3050
+cpu 		CPU_MIPS24K
+
+# Include optional configuration (to be edited by the user if needed)
+include 	MEDIATEK

sys/mips/conf/RT3352_FDT

@@ -0,0 +1,30 @@
+#
+# RT3352_FDT -- Kernel configuration file for FreeBSD/MIPS RT3352 SoC
+#
+# This includes all the configurable parts of the kernel. Please read through
+# MEDIATEK kernel config and customize the options to fit your board if needed.
+#
+# $FreeBSD$
+#
+
+#NO_UNIVERSE
+
+#
+# FDT_DTS_FILE should be modified to suit the target board type.
+#
+#makeoptions 	FDT_DTS_FILE=DIR-615-H1.dts
+
+#
+# The user should never have to edit what's below this line.
+# If customizations are needed, they should be done to the MEDIATEK kernel
+# configuration.
+#
+
+# Start with a base configuration
+include 	MEDIATEK_BASE
+
+ident 		RT3352
+cpu 		CPU_MIPS24K
+
+# Include optional configuration (to be edited by the user if needed)
+include 	MEDIATEK

sys/mips/conf/RT3883_FDT

@@ -0,0 +1,30 @@
+#
+# RT3883_FDT -- Kernel configuration file for FreeBSD/MIPS RT3662/RT3883 SoCs
+#
+# This includes all the configurable parts of the kernel. Please read through
+# MEDIATEK kernel config and customize the options to fit your board if needed.
+#
+# $FreeBSD$
+#
+
+#NO_UNIVERSE
+
+#
+# FDT_DTS_FILE should be modified to suit the target board type.
+#
+#makeoptions 	FDT_DTS_FILE=DIR-645.dts
+
+#
+# The user should never have to edit what's below this line.
+# If customizations are needed, they should be done to the MEDIATEK kernel
+# configuration.
+#
+
+# Start with a base configuration
+include 	MEDIATEK_BASE
+
+ident 		RT3883
+cpu 		CPU_MIPS74K
+
+# Include optional configuration (to be edited by the user if needed)
+include 	MEDIATEK

sys/mips/conf/RT5350_FDT

@@ -0,0 +1,30 @@
+#
+# RT5350_FDT -- Kernel configuration file for FreeBSD/MIPS RT5350 SoC
+#
+# This includes all the configurable parts of the kernel. Please read through
+# MEDIATEK kernel config and customize the options to fit your board if needed.
+#
+# $FreeBSD$
+#
+
+#NO_UNIVERSE
+
+#
+# FDT_DTS_FILE should be modified to suit the target board type.
+#
+#makeoptions 	FDT_DTS_FILE=DIR-300-B7.dts
+
+#
+# The user should never have to edit what's below this line.
+# If customizations are needed, they should be done to the MEDIATEK kernel
+# configuration.
+#
+
+# Start with a base configuration
+include 	MEDIATEK_BASE
+
+ident 		RT5350
+cpu 		CPU_MIPS24K
+
+# Include optional configuration (to be edited by the user if needed)
+include 	MEDIATEK