modules 	:=
pwd 		:= $(shell pwd)
packages 	:= $(pwd)/packages
build		:= $(pwd)/build
config		:= $(pwd)/build
INSTALL		:= $(pwd)/install

# Currently supported targets are x230, chell and qemu
BOARD		?= qemu

# If musl-libc is being used in the initrd, set the heads_cc
# variable to point to it.
musl_dep	:= musl
heads_cc	:= $(INSTALL)/bin/musl-gcc

all: $(BOARD).rom

# Disable all built in rules
.SUFFIXES:


# Bring in all of the module definitions;
# these are the external pieces that will be downloaded and built
# as part of creating the Heads firmware image.
include modules/*

# These will be built via their intermediate targets
# This increases the build time, so it is commented out for now
#all: $(foreach m,$(modules),$m.intermediate)

define prefix =
$(foreach _, $2, $1$_)
endef

define bins =
$(foreach m,$1,$(call prefix,$(build)/$($m_dir)/,$($m_output)))
endef
define libs =
$(foreach m,$1,$(call prefix,$(build)/$($m_dir)/,$($m_libraries)))
endef

define outputs =
$(foreach m,$1,\
	$(call bins,$m)\
	$(call libs,$m)\
)
endef

#
# Generate the targets for a module.
#
# Special variables like $@ must be written as $$@ to avoid
# expansion during the first evaluation.
#
define define_module =
  ifneq ("$($1_repo)","")
    # Checkout the tree instead and touch the canary file so that we know
    # that the files are all present. No signature hashes are checked in
    # this case, since we don't have a stable version to compare against.
    $(build)/$($1_dir)/.canary:
	git clone "$($1_repo)" "$(build)/$($1_dir)"
	touch "$$@"
  else
    # Fetch and verify the source tar file
    $(packages)/$($1_tar):
	wget -O "$$@" $($1_url)
    $(packages)/.$1_verify: $(packages)/$($1_tar)
	echo "$($1_hash)  $$^" | sha256sum --check -
	touch "$$@"

    # Unpack the tar file and touch the canary so that we know
    # that the files are all present
    $(build)/$($1_dir)/.canary: $(packages)/.$1_verify
	tar -xf "$(packages)/$($1_tar)" -C "$(build)"
	if [ -r patches/$1-$($1_version).patch ]; then \
		( cd $(build)/$($1_dir) ; patch -p1 ) \
			< patches/$1-$($1_version).patch; \
	fi
	touch "$$@"
  endif

  ifeq "$($1_config)" ""
    # There is no official .config file
    $(build)/$($1_dir)/.config: $(build)/$($1_dir)/.canary
	touch "$$@"
  else
    # Copy the stored config file into the unpacked directory
    $(build)/$($1_dir)/.config: config/$($1_config) $(build)/$($1_dir)/.canary
	cp -a "$$<" "$$@"
  endif


  # Use the module's configure variable to build itself
  $(build)/$($1_dir)/.configured: \
		$(build)/$($1_dir)/.canary \
		$(build)/$($1_dir)/.config
	cd "$(build)/$($1_dir)" ; $($1_configure)
	touch "$$@"

  # Build the target after any dependencies
  $(call outputs,$1): $1.intermediate

  # Short hand target for the module
  #$1: $(call outputs,$1)

  # Target for all of the outputs, which depend on their dependent modules
  $1.intermediate: \
		$(foreach d,$($1_depends),$(call outputs,$d)) \
		$(foreach d,$($1_depends),$d.intermediate) \
		$(build)/$($1_dir)/.configured
	make -C "$(build)/$($1_dir)" $($1_target)

.INTERMEDIATE: $1.intermediate
endef

$(foreach _, $(modules), $(eval $(call define_module,$_)))

initrd_lib_dir := initrd/lib
initrd_bin_dir := initrd/bin

#
# Install a file into the initrd, if it changed from
# the destination file.
#
define install =
	cmp --quiet "$1" "$2" || \
	cp -a "$1" "$2"
endef

#
# Files that should be copied into the initrd
# THis should probably be done in a more scalable manner
#
define initrd_bin_add =
$(initrd_bin_dir)/$(notdir $1): $1
	@if [ ! -d "$(initrd_bin_dir)" ]; \
		then mkdir -p "$(initrd_bin_dir)"; \
	fi
	$(call install,$$<,$$@)
initrd_bins += $(initrd_bin_dir)/$(notdir $1)
endef


define initrd_lib_add =
$(initrd_lib_dir)/$(notdir $1): $1
	@if [ ! -d "$(initrd_lib_dir)" ]; \
		then mkdir -p "$(initrd_lib_dir)"; \
	fi
	$(call install,$$<,$$@)
initrd_libs += $(initrd_lib_dir)/$(notdir $1)
endef

$(foreach _, $(call bins,kexec), $(eval $(call initrd_bin_add,$_)))
$(foreach _, $(call bins,tpmtotp), $(eval $(call initrd_bin_add,$_)))
$(foreach _, $(call bins,cryptsetup), $(eval $(call initrd_bin_add,$_)))
$(foreach _, $(call bins,gpg), $(eval $(call initrd_bin_add,$_)))
$(foreach _, $(call bins,lvm2), $(eval $(call initrd_bin_add,$_)))

$(foreach _, $(call libs,tpmtotp), $(eval $(call initrd_lib_add,$_)))
$(foreach _, $(call libs,mbedtls), $(eval $(call initrd_lib_add,$_)))
$(foreach _, $(call libs,qrencode), $(eval $(call initrd_lib_add,$_)))
$(foreach _, $(call libs,lvm2), $(eval $(call initrd_lib_add,$_)))

#$(foreach _, $(call outputs,xen), $(eval $(call initrd_bin,$_)))

# hack to install busybox into the initrd
initrd_bins += initrd/bin/busybox

initrd/bin/busybox: $(build)/$(busybox_dir)/busybox
	cmp --quiet "$@" "$^" || \
	make \
		-C $(build)/$(busybox_dir) \
		CC="$(heads_cc)" \
		CONFIG_PREFIX="$(pwd)/initrd" \
		-j 8 \
		install

# hack to build cbmem from coreboot
# this must be built *AFTER* musl
initrd_bins += initrd/bin/cbmem
initrd/bin/cbmem: $(build)/$(coreboot_dir)/util/cbmem/cbmem
	cmp --quiet "$^" "$@" \
	|| cp "$^" "$@"
$(build)/$(coreboot_dir)/util/cbmem/cbmem: \
		$(build)/$(coreboot_dir)/.canary \
		musl.intermediate
	make -C "$(dir $@)" CC="$(heads_cc)"


# Update all of the libraries in the initrd based on the executables
# that were installed.
initrd_lib_install: $(initrd_bins) $(initrd_libs)
	-find initrd/bin -type f -a ! -name '*.sh' -print0 \
		| xargs -0 strip
	LD_LIBRARY_PATH="$(INSTALL)/lib" \
	./populate-lib \
		$(initrd_lib_dir) \
		initrd/bin/* \
		initrd/sbin/* \

	-strip $(initrd_lib_dir)/* ; true


#
# initrd image creation
#
# The initrd is constructed from various bits and pieces
# The cpio-clean program is used ensure that the files
# always have the same timestamp and appear in the same order.
#
# If there is no /dev/console, initrd can't startup.
# We have to force it to be included into the cpio image.
# Since we are picking up the system's /dev/console, there
# is a chance the build will not be reproducible (although
# unlikely that their device file has a different major/minor)
#
#
initrd.cpio: $(initrd_bins) $(initrd_libs) initrd_lib_install
	cd ./initrd ; \
	( \
		echo "/dev" ; \
		echo "/dev/console"; \
		find . \
	) \
	| cpio --quiet -H newc -o \
	| ../cpio-clean \
		> "../$@.tmp"
	if ! cmp --quiet "$@" "$@.tmp"; then \
		mv "$@.tmp" "$@"; \
	else \
		echo "$@: Unchanged"; \
		rm "$@.tmp"; \
	fi

initrd.intermediate: initrd.cpio


# populate the coreboot initrd image from the one we built.
# 4.4 doesn't allow this, but building from head does.
$(call outputs,linux): initrd.cpio
#$(call outputs,coreboot): $(build)/$(coreboot_dir)/initrd.cpio.xz
$(build)/$(coreboot_dir)/initrd.cpio.xz: initrd.cpio
	xz --extreme < "$<" > "$@"

# hack for the coreboot to find the linux kernel
$(build)/$(coreboot_dir)/bzImage: $(call outputs,linux)
	cmp --quiet "$@" "$^" || \
	cp -a "$^" "$@"
$(call outputs,coreboot): $(build)/$(coreboot_dir)/bzImage


# The coreboot gcc won't work for us since it doesn't have libc
#XGCC := $(build)/$(coreboot_dir)/util/crossgcc/xgcc/
#export CC := $(XGCC)/bin/x86_64-elf-gcc
#export LDFLAGS := -L/lib/x86_64-linux-gnu

x230.rom: $(build)/$(coreboot_dir)/x230/coreboot.rom
	dd if="$<" of="$@" bs=1M skip=8

qemu.rom: $(build)/$(coreboot_dir)/qemu/coreboot.rom
	cp -a "$<" "$@"

clean-modules:
	for dir in busybox-1.25.0 cryptsetup-1.7.3 gnupg-1.4.21 kexec-tools-2.0.12 libuuid-1.0.3 LVM2.2.02.168 mbedtls-2.3.0 popt-1.16 qrencode-3.4.4 tpmtotp-git ; do \
		make -C build/$$dir clean; \
		rm build/$$dir/.configured; \
	done