# Maintainer: Antoine Martin (ayakael) <dev@ayakael.net>
# Contributor: Antoine Martin (ayakael) <dev@ayakael.net>

pkgname=linux-rm
pkgver=5.4.70
_rmver=1.3.3
pkgrel=2
pkgdesc="Linux kernel with reMarkable patches"
url=https://github.com/reMarkable/linux
depends="initramfs-generator linux-firmware-brcm linux-firmware-cypress"
_depends_dev="perl gmp-dev elfutils-dev bash mpc1-dev mpfr-dev"
makedepends="$_depends_dev sed installkernel bc linux-headers linux-firmware mawk
	bison flex openssl-dev>3 diffutils pahole findutils xz lzop
"
options="!strip !check"
builddir="$srcdir"/linux-RM1XX_${pkgver}_v$_rmver
source="
	https://github.com/reMarkable/linux/archive/refs/tags/RM1XX_${pkgver}_v$_rmver.tar.gz
	enable-automatic-partial-refreshing.patch
	enable-sdhc1.patch
	config-changes-rm.armv7
	config-changes-rm.armhf
	"
arch="armv7 armhf"
license="GPL-2.0"
for _i in $source; do
	case $_i in
	config-*.$CARCH)
		_f=${_i%."$CARCH"}
		_f=${_f#config-changes-}
		_flavors="$_flavors $_f"
		[ "linux-$_f" != "$pkgname" ] && subpackages="$subpackages linux-$_f::$CTARGET_ARCH"
		subpackages="$subpackages linux-$_f-dev:_dev:$CBUILD_ARCH"
		;;
	esac
done

_carch=$CARCH
case "$CARCH" in
	aarch64) _carch="arm64" ;;
	arm*) _carch="arm" ;;
esac

# generate config from defconfig and apply local changes.
# config-changes-$flavor.$CARCH holds a list of = delimited
# config command and values used by kernel scripts/config script.
_genconfig() {
	local flavor=$1 defconfig=
	local subbuilddir="$srcdir"/build-$flavor
	local defconfig=
	case $flavor in
		rm) defconfig=zero-gravitas_defconfig ;;
		rm2) defconfig=zero-sugar_defconfig ;;
		*) die "Unknown flavor: $flavor" ;;
	esac

	cp "$builddir"/arch/$_carch/configs/$defconfig \
		"$subbuilddir"/.config

	while read -r line; do
		# skip comments
		case "$line" in
			"#"*) continue;;
		esac
		local option=${line%%=*} str=
		local cmd=$(echo $line | cut -d= -f2)
		case "$cmd" in
			y) cmd="enable";;
			n) cmd="disable";;
			m) cmd="module";;
			'"'*) cmd="set-str"; str="${line#*=}";;
			[0-9]*) cmd="set-val"; str="${line#*=}";;
			*) die "Command $cmd not accepted" ;;
		esac
		msg "[$flavor] $cmd: $option $str"
		"$builddir"/scripts/config \
			--file "$subbuilddir"/.config \
			--$cmd "$option" "${str//\"/}"
	done < "$srcdir"/config-changes-$flavor.$CARCH
}

# verify if options are set to correct value
_verifyconfig() {
	local flavor=$1
	local subbuilddir="$srcdir"/build-$flavor
	while read -r line; do
		[ ${line:0:1} = "#" ] && continue
		local option=${line%%=*} str= invert=
		local cmd=$(echo $line | cut -d= -f2)
		case "$cmd" in
			enable) str="$option=y" ;;
			disable) str="$option"; invert="-v" ;;
			module) str="$option=m" ;;
			set-val) str="$option=${line##*=}" ;;
			set-str) str=${line##*=}
				str="$option=\"${str//\"/}\"" ;;
		esac
		grep -q $invert "^$str" "$subbuilddir"/.config || \
			die "Config: $option not properly set!"
	done < "$srcdir"/config-changes-$flavor.$CARCH
}

prepare() {
	default_prepare

	local flavor=
	for flavor in $_flavors; do
		local _builddir="$srcdir"/build-$flavor
		mkdir -p "$_builddir"
		echo "-$pkgrel-$flavor" > "$_builddir"/localversion-alpine
		_genconfig $flavor
		make -C "$builddir" \
			O="$_builddir" \
			ARCH="$_carch" \
			olddefconfig
		_verifyconfig $flavor
	done
}

build() {
	unset LDFLAGS
	for i in $_flavors; do
		cd "$srcdir"/build-$i
		local _kver=$(make kernelversion)
		if [ "$_kver" != "$pkgver" ]; then
			error "Version in Makefile ($_kver) does not correspond with pkgver ($pkgver)"
			return 1
		fi

		make ARCH="$_carch" CC="${CC:-gcc}" KLZOP="/usr/bin/lzop" \
			KBUILD_BUILD_VERSION="$((pkgrel + 1 ))-Alpine"
	done
}

_package() {
	local _flavor="$1" _outdir="$2"
	local _builddir="$srcdir"/build-$_flavor
	local _abi_release="$(make -C "$_builddir" -s kernelrelease)"

	cd "$srcdir"/build-$_flavor

	mkdir -p "$_outdir"/boot "$_outdir"/lib/modules

	local _install="zinstall dtbs_install"

	cd "$srcdir"/build-$_flavor
	# modules_install seems to regenerate a defect Modules.symvers. Work
	# around it by backing it up and restore it after modules_install
	cp Module.symvers Module.symvers.backup

	local INSTALL_DTBS_PATH="$_outdir"/boot
	make -j1 modules_install $_install \
		ARCH="$_carch" \
		INSTALL_MOD_PATH="$_outdir" \
		INSTALL_MOD_STRIP=1 \
		INSTALL_PATH="$_outdir"/boot \
		INSTALL_DTBS_PATH="$INSTALL_DTBS_PATH"
	cp Module.symvers.backup Module.symvers

	cp "$_builddir"/arch/arm/boot/zImage "$_outdir"/boot/zImage
	rm "$_outdir"/boot/vmlinuz-$_flavor

	rm -f "$_outdir"/lib/modules/$_abi_release/build \
		"$_outdir"/lib/modules/$_abi_release/source
	rm -rf "$_outdir"/lib/firmware

	install -D -m644 include/config/kernel.release \
		"$_outdir"/usr/share/kernel/$_flavor/kernel.release
}

# main flavor installs in $pkgdir
package() {
	_package rm "$pkgdir"
}

# subflavors install in $subpkgdir
rm2() {
	depends="initramfs-generator linux-firmware-brcm linux-firmware-cypress"
	_package rm2 "$subpkgdir"
}

_dev() {
	local _flavor=$(echo $subpkgname | sed -E 's/(^linux-|-dev$)//g')
	local _builddir="$srcdir"/build-$_flavor
	local _abi_release="$(make -C "$_builddir" -s kernelrelease)"
	# copy the only the parts that we really need for build 3rd party
	# kernel modules and install those as /usr/src/linux-headers,
	# simlar to what ubuntu does
	#
	# this way you dont need to install the 300-400 kernel sources to
	# build a tiny kernel module
	#
	pkgdesc="Headers and script for third party modules for $_flavor kernel"
	depends="$_depends_dev"
	local dir="$subpkgdir"/usr/src/linux-headers-$_abi_release

	# first we import config, run prepare to set up for building
	# external modules, and create the scripts
	mkdir -p "$dir"
	cp "$_builddir"/.config "$dir"/.config
	echo "-$pkgrel-$_flavor" > "$dir"/localversion-alpine

	make -j1 -C "$builddir" \
		O="$dir" \
		ARCH="$_carch" \
		AWK="${AWK:-mawk}" \
		syncconfig prepare modules_prepare scripts

	# remove the stuff that points to real sources. we want 3rd party
	# modules to believe this is the soruces
	rm "$dir"/Makefile "$dir"/source

	# copy the needed stuff from real sources
	#
	# this is taken from ubuntu kernel build script
	# http://kernel.ubuntu.com/git/ubuntu/ubuntu-zesty.git/tree/debian/rules.d/3-binary-indep.mk
	cd "$builddir"
	find .  -path './include/*' -prune \
		-o -path './scripts/*' -prune -o -type f \
		\( -name 'Makefile*' -o -name 'Kconfig*' -o -name 'Kbuild*' -o \
		   -name '*.sh' -o -name '*.pl' -o -name '*.lds' \) \
		-print | cpio -pdm "$dir"

	cp -a scripts include "$dir"

	# shellcheck disable=SC2046
	find $(find arch -name include -type d -print) -type f \
		| cpio -pdm "$dir"

	install -Dm644 "$_builddir"/Module.symvers \
		"$dir"/Module.symvers

	mkdir -p "$subpkgdir"/lib/modules/$_abi_release
	ln -sf /usr/src/linux-headers-$_abi_release \
		"$subpkgdir"/lib/modules/$_abi_release/build
}

sha512sums="
80ab274ca3d30935d9913490662f17499c1ceedb438fe171554097d25ffc1cf85ee53f0c1642e94c0b833fdfb17636cd554bf685e4a6f5dac20cf122c1a25447  RM1XX_5.4.70_v1.3.3.tar.gz
0f47278c5bfafb939e46224fbf16f9491e3cc560ac128dcf430a1f6cf9064fb1c5bf5db1a3076c35d30c004aec525a7d6616a647564f197bb29c57701c1db982  enable-automatic-partial-refreshing.patch
6f2036a2f88b0d80ba5e37e3d119aebd2dc33453f5a5d84b319ec50c0c00d8cb93fc4b3f5e10f3d56c1496f3cb297551c405f36c5d864af112398f0792f1549a  enable-sdhc1.patch
7f118de35f63960c0d9dc8d8ed56c4097006a3545d4672b618b1d430a7a9c018dbda4c2bfe900cd013c5f65766ddd62b1638ddfeb1bafde307f77d25891bd438  config-changes-rm.armv7
7f118de35f63960c0d9dc8d8ed56c4097006a3545d4672b618b1d430a7a9c018dbda4c2bfe900cd013c5f65766ddd62b1638ddfeb1bafde307f77d25891bd438  config-changes-rm.armhf
"