#!/bin/bash
# SPDX-License-Identifier: GPL-2.0+

set -e

kbuild_root=$(dirname $(readlink -f "$0"))
kernel_root="${PWD}"
kernel_output="${kernel_root}/output"

declare -A cross_compile
declare -A extra_kcflags
declare -A target_root

if [[ -r $kbuild_root/config.sh ]] ; then
	source $kbuild_root/config.sh || exit 1
fi

#kbuild_options='CONFIG_DEBUG_SECTION_MISMATCH=y'
#kbuild_options='C=1'
kbuild_options="KALLSYMS_EXTRA_PASS=0"

get_kernel_version() {
	local version=$(cat Makefile | grep '^VERSION = ' | sed 's/.* = //')
	local patchlevel=$(cat Makefile | grep '^PATCHLEVEL = ' | sed 's/.* = //')
	local sublevel=$(cat Makefile | grep '^SUBLEVEL = ' | sed 's/.* = //')
	echo "$version.$patchlevel.$sublevel"
}

version=$(get_kernel_version)

#
# Options parsing
#

usage() {
	echo   "Usage: $(basename $1) [options] platform [make options]"
	echo   ""
	echo   "Supported options:"
	echo   "--bootloader file	Boot loader file (CrOS images only)"
	echo   "--build components	List of components to build: image, modules, dt (default: all)"
	echo   "--cmdline		Command line arguments file (CrOS images only)"
	echo   "--config		Run menuconfig"
	echo   "--deb			Create Debian packages"
	echo   "--defconfig file	Generate a new .config with defaults from file"
	echo   "--doc[=dir]		Compile the documentation (for the specified dir only)"
	echo   "--dt-check file		Run DT bindings checks"
	echo   "-h, --help		Print this help text"
	echo   "--			End options parsing, next argument is the platform"
	echo   ""
	echo   "Supported platforms:"
	for f in $kbuild_root/platforms/*.sh ; do
		echo "- $(basename -s .sh $f)"
	done
}

declare -A do_build
do_menu_config=0
do_package_deb=0
opt_bootloader=
opt_build="image,modules,dt"
opt_cmdline_file=
opt_defconfig=
opt_doc_dirs='.'
opt_dt_bindings=''
opt_make_opts=

while [[ $# != 0 ]] ; do
	option=$1
	shift

	case $option in
		--bootloader)
			opt_bootloader=$1
			if [[ ! -r $opt_bootloader ]] ; then
				echo "Boot loader file $opt_bootloader is not readable"
				exit 1
			fi
			shift
			;;
		--build)
			opt_build="$1"
			shift
			;;
		--cmdline)
			opt_cmdline_file=$1
			if [[ ! -r $opt_cmdline_file ]] ; then
				echo "Command line file $opt_cmdline_file is not readable"
				exit 1
			fi
			shift
			;;
		--config)
			do_menu_config=1
			;;
		--deb)
			do_package_deb=1
			;;
		--defconfig)
			opt_defconfig=$1
			if [[ ! -r $opt_defconfig ]] ; then
				echo "defconfig file $opt_defconfig is not readable"
				exit 1
			fi
			shift
			;;
		--doc)
			do_build[doc]=1
			;;
		--doc=*)
			do_build[doc]=1
			opt_doc_dirs="${option/--doc=/}"
			;;
		--dt-check)
			opt_dt_bindings="$1"
			shift
			;;
		-h|--help)
			usage $0
			exit 1
			;;
		--)
			platform=auto
			;;
		--*)
			echo "Unrecognized option $option"
			exit 1
			;;
		*)
			if [[ -z "$platform" ]] ; then
				platform=$option
			else
				opt_make_opts="$option $opt_make_opts"
			fi
			;;
	esac
done

IFS=',' read -r -a opt_build <<< "$opt_build"
for component in ${opt_build[@]} ; do
	case $component in
	dt|image|modules)
		do_build[$component]=1
		;;
	*)
		echo "Invalid build component ${component}"
		exit 1
		;;
	esac
done

#
# Platform
#

kcflags="-Werror -Wno-error=cpp"

if [[ -z "$platform" || "$platform" == "auto" ]] ; then
	for f in $kbuild_root/platforms/*.sh ; do
		pattern=$(cat $f | grep "dir_pattern=" | head -1)
		pattern=${pattern/#dir_pattern=/}
		if [[ -n "$pattern" ]] ; then
			echo "$kernel_root" | grep -q "/$pattern/" || continue
			platform=$(basename -s .sh $f)
			break
		fi
	done
fi

if [[ ! -r "$kbuild_root/platforms/$platform.sh" ]] ; then
	echo "Unknown platform '$platform'. Supported platforms are"
	for f in $kbuild_root/platforms/*.sh ; do
		echo "- $(basename -s .sh $f)"
	done
	exit 1
fi

source "${kbuild_root}/platforms/$platform.sh" || exit 1

# Apply version-specific kcflags, useful to suppress warnings based on the
# kernel version.
[[ -z "${extra_kcflags[$version]+_}" ]] || kcflags="$kcflags ${extra_kcflags[$version]}"

#
# Architecture
#

if [[ ! -r "$kbuild_root/arch/$arch.sh" ]] ; then
	echo "Unknown architecture '$arch'. Supported architectures are"
	for f in $kbuild_root/arch/*.sh ; do
		echo "- $(basename -s .sh $f)"
	done
	exit 1
fi

source "${kbuild_root}/arch/$arch.sh" || exit 1

# Override the output directory for ARM for historical reasons
case $arch in
	arm)
		output_dir="$kernel_output/arm32"
		;;
	*)
		output_dir="$kernel_output/$arch"
		;;
esac

#
# Build environment and tools
#

num_cpus=$(cat /proc/cpuinfo | grep '^processor\b' | wc -l)
make="make ARCH=$arch O=$output_dir CROSS_COMPILE=${cross_compile[$arch]} ${extra_make_args}"
pmake="$make -j$((num_cpus*2)) $opt_make_opts"

echo "Compiling for platform $platform with $num_cpus CPUs"

mkdir -p $output_dir/

if [[ -n "$opt_defconfig" ]] ; then
	mkdir -p $output_dir/arch/$arch/configs/
	cp $opt_defconfig $output_dir/arch/$arch/configs/build_defconfig
	$make build_defconfig
	rm $output_dir/arch/$arch/configs/build_defconfig
fi

if [[ $do_menu_config == 1 ]] ; then
	$make menuconfig
	exit 0
fi

#
# Compile documentation if requested
#

if [[ ${do_build[doc]} == 1 ]] ; then
	(
	if [[ ! -f "$kernel_output/doc/bin/activate" ]] ; then
		virtualenv "$kernel_output/doc"
		source "$kernel_output/doc/bin/activate"
		pip install -r Documentation/sphinx/requirements.txt
	else
		source "$kernel_output/doc/bin/activate"
	fi

	$pmake SPHINXDIRS="${opt_doc_dirs}" htmldocs
	)
fi

#
# Check DT bindings
#

if [[ ! -z ${opt_dt_bindings} ]] ; then
	$pmake dt_binding_check DT_CHECKER_FLAGS=-m "DT_SCHEMA_FILES=${opt_dt_bindings}"
fi

#
# Compile the kernel, modules and DTBs
#

kernel_dtbs=
if [[ ${do_build[dt]} == 1 ]] ; then
	for dtb in ${dtbs[@]} ; do
		dtb=${dtb/:*/}

		if [[ "${dtb}" == /* ]] ; then
			continue
		fi

		kernel_dtbs="$kernel_dtbs $dtb"
	done
fi

if [[ ${do_build[image]} == 1 ]] ; then
	$pmake $kbuild_options KCFLAGS="$kcflags" $image_kernel $kernel_dtbs
fi

grep 'CONFIG_MODULES=y' $output_dir/.config > /dev/null && modules=modules
if [[ x$modules == xmodules ]] && [[ ${do_build[modules]} == 1 ]]; then
	$pmake $kbuild_options KCFLAGS="$kcflags" $modules
fi

version=$(cat $output_dir/include/generated/utsrelease.h | cut -d '"' -f 2)

#
# Create the image
#

_image_type=${image/:*/}

if [[ -r "$kbuild_root/images/${_image_type}.sh" ]] ; then
	source "${kbuild_root}/images/${_image_type}.sh" || exit 1
	eval make_${_image_type}_image
else
	_image_file=${_image_type}
fi

if echo "${image}" | grep -q ':' ; then
	_image_name=${image/*:/}
else
	_image_name=${_image_file}
fi

_image_file="$output_dir/arch/$arch/boot/${_image_file}"

#
# Copy the files to their destination directories.
#
# The kernel image and DTBs are copied to both $target_dir/boot and $tftp_dir
# (if available). When the image format is CrOS, installation to $tftp_dir is
# skipped as Chrome OS devices can't boot from TFTP.
#
# The modules are installed to $target_dir if available, or to
# $output_dir/modules otherwise.
#

target_dir=${target_dir:-${target_root[$arch]}}
tftp_dir=${tftp_dir:-$tftp_root/$platform}

copy_dtbs() {
	local dest_dir=$1
	local dtb

	if [[ ${do_build[dt]} != 1 ]] ; then
		return
	fi

	if [[ $_image_type == FIT || $_image_type == CrOS ]] ; then
		return
	fi

	for dtb in ${dtbs[@]} ; do
		local src=${dtb/:*/}
		local dst=${dtb/*:/}

		# If a destination is explicitly specified, don't strip
		# directory name. This can be used for instance to store .dtbo
		# files in an overlays/ subdirectory.
		if ! echo ${dtb} | grep -q ':' ; then
			dst=$(basename $dst)
		fi

		# The destination should never be an absolute path.
		if [[ "${dst}" == /* ]] ; then
			echo "Error: DTB destination ${dtb} can't be absolute path"
			exit 1
		fi

		mkdir -p $(dirname $dest_dir/$dst)
		cp $output_dir/arch/${arch}/boot/dts/$src* $dest_dir/$dst
	done
}

if [[ -d "$target_dir" ]] ; then
	mkdir -p $target_dir/boot
	cp ${_image_file} $target_dir/boot/${_image_name}
	copy_dtbs $target_dir/boot/
fi

if [[ $_image_type != CrOS && -d "$tftp_dir" ]] ; then
	cp ${_image_file} $tftp_dir/${_image_name}
	copy_dtbs $tftp_dir/
fi

if [[ x$modules == xmodules ]] && [[ ${do_build[modules]} == 1 ]]; then
	mod_path=${target_dir:-$output_dir/modules}
	mkdir -p $mod_path
	$pmake INSTALL_MOD_PATH=$mod_path modules_install
fi

#
# Create the Debian package if requested
#

if [[ $do_package_deb == 1 ]] ; then
	$pmake $kbuild_options KCFLAGS="$kcflags" DPKG_FLAGS="-d" bindeb-pkg
fi

#
# Print status and terminate
#

echo "Kernel image available in ${_image_file}"
if [[ x$modules == xmodules ]] && [[ ${do_build[modules]} == 1 ]]; then
	echo "Kernel modules installed to $mod_path/lib/modules/$version"
fi
echo "Build $version completed at $(date)"