RM= rm
CC= $(CONFIG_TARGET_CC)
AS= $(CONFIG_TARGET_CC)
# NOTE(dinosaure): we must use [aarch64-none-elf-gcc] to compile assembly code
# to be able to include some files and define some macros.
LD= $(CONFIG_TARGET_LD)
AR= $(CONFIG_TARGET_AR)
OBJDUMP= $(CONFIG_TARGET_OBJDUMP)
OBJCOPY= $(CONFIG_TARGET_OBJCOPY)

export TOPDIR := $(abspath .)

$(TOPDIR)/Makeconf:
	$(error Makeconf not found, please run ./configure.sh)

include $(TOPDIR)/Makeconf

include/$(CONFIG_TARGET_TRIPLE):
	@echo "GEN $@"
	@./gen-headers.sh $@

CPU ?= -mcpu=cortex-a76 -mlittle-endian
ARCH += -DAARCH=64 $(CPU)
TARGET ?= kernel_2712

DEFINE += -DSSP_GUARD_SYMBOL=__stack_chk_guard \
	-DSSP_FAIL_SYMBOL=__stack_chk_fail

INCLUDE += -I $(TOPDIR)/include -I $(TOPDIR)/include/$(CONFIG_TARGET_TRIPLE) \
	-I $(TOPDIR)/nolibc/include -I $(TOPDIR)/openlibm/include -I $(TOPDIR)/openlibm/src

AFLAGS += $(ARCH) $(DEFINE) $(INCLUDE)

# CFLAGS & LDFLAGS are used with $(CC). Link arguments must be passed with -Wl
# Also, CONFIG_TARGET_LD_LDFLAGS are specific when we use CONFIG_TARGET_LD

CFLAGS += -ffreestanding -fstack-protector-strong -nostdlib \
	-nostartfiles -mstrict-align -Wall \
	$(ARCH) $(DEFINE) $(INCLUDE) $(CONFIG_TARGET_CC_CFLAGS)

comma := ,
empty:=
space := $(empty) $(empty)

LDFLAGS += -static -Wl,--no-warn-rwx-segments \
	-Wl,--section-start=.init=0x80000 \
	-Wl,--start-group \
	-L lib/$(CONFIG_TARGET_TRIPLE) -lgilbraltar -lopenlibm -lnolibc -lgcc \
	-Wl,--end-group \
	-Wl,$(subst $(space),$(comma),${CONFIG_TARGET_CC_LDFLAGS})

LD_LDFLAGS += -static --no-warn-rwx-segments \
	--section-start=.init=0x80000 \
	--start-group \
	-L lib/$(CONFIG_TARGET_TRIPLE) -lgilbraltar -lopenlibm -lnolibc -lgcc \
	--end-group \
	${CONFIG_TARGET_CC_LDFLAGS}

SRCS= kernel.c timer.c led.c interrupt_handler.c exception_handler.c \
	mbox.c clock.c crt.c serial.c log.c power.c tag.c coherent_page.c dtb.c \
	synchronize.c spinlock.c memory.c pager.c translation_table.c

ASMS= startup.S exception_stub.S

SRCS:=$(addprefix kernel/,$(SRCS))
ASMS:=$(addprefix kernel/,$(ASMS))

OBJS= $(SRCS:c=o) $(ASMS:S=o)

ALLTOOLS := gcc cc ar as ld nm objcopy objdump ranlib readelf strip
ALLTOOLS := $(foreach tool,$(ALLTOOLS),\
						$(CONFIG_TARGET_TRIPLE)-$(tool))
TOOLCHAIN_FOR_BUILD := $(addprefix bin/build/,$(ALLTOOLS))

bin/build:
	@test ! -d $@
	@mkdir -p $@

bin/build/$(CONFIG_TARGET_TRIPLE)-%: toolchain/%.in | bin/build
	@echo "SUBST $@"
	@sed -e 's!@@CONFIG_TARGET_ARCH@@!$(CONFIG_TARGET_ARCH)!g'             \
	    -e 's!@@CONFIG_TARGET_TRIPLE@@!$(CONFIG_TARGET_TRIPLE)!g'          \
	    -e 's!@@CONFIG_TARGET_CC@@!$(CONFIG_TARGET_CC)!g'                  \
	    -e 's!@@CONFIG_TARGET_CC_CFLAGS@@!$(CFLAGS)!g'                     \
	    -e 's!@@CONFIG_TARGET_CC_LDFLAGS@@!$(LDFLAGS)!g'                   \
	    -e 's!@@CONFIG_TARGET_LD@@!$(CONFIG_TARGET_LD)!g'                  \
	    -e 's!@@CONFIG_TARGET_LD_LDFLAGS@@!$(LD_LDFLAGS)!g'  \
	    -e 's!@@CONFIG_TARGET_OBJCOPY@@!$(CONFIG_TARGET_OBJCOPY)!g'        \
	    -e 's!@@CONFIG_HOST_CC@@!$(CONFIG_HOST_CC)!g'                      \
	    -e 's!@@CONFIG_TARGET_NM@@!$(CONFIG_TARGET_NM)!g'                  \
	    -e 's!@@CONFIG_TARGET_OBJDUMP@@!$(CONFIG_TARGET_OBJDUMP)!g'        \
	    -e 's!@@CONFIG_TARGET_AR@@!$(CONFIG_TARGET_AR)!g'                  \
	    -e 's!@@CONFIG_TARGET_RANLIB@@!$(CONFIG_TARGET_RANLIB)!g'          \
	    -e 's!@@CONFIG_TARGET_STRIP@@!$(CONFIG_TARGET_STRIP)!g'            \
	    $< >$@
	@chmod +x $@

.PHONY: toolchains
toolchains: bin/build

%.o: %.S
	@echo "AS $@"
	@$(AS) $(AFLAGS) -c -o $@ $<

%.o: %.c include/$(CONFIG_TARGET_TRIPLE)
	@echo "CC $@"
	@$(CC) $(CFLAGS) -c -o $@ $<

lib/$(CONFIG_TARGET_TRIPLE):
	@test ! -d $@
	@mkdir -p $@

lib/$(CONFIG_TARGET_TRIPLE)/libgilbraltar.a: $(OBJS) | lib/$(CONFIG_TARGET_TRIPLE)
	@echo "AR $@"
	@rm -f $@
	@$(AR) cr $@ $^

lib/$(CONFIG_TARGET_TRIPLE)/libnolibc.a: nolibc/libnolibc.a | lib/$(CONFIG_TARGET_TRIPLE)
	@echo "COPY $@"
	@cp $^ $@

lib/$(CONFIG_TARGET_TRIPLE)/libopenlibm.a: openlibm/libopenlibm.a | lib/$(CONFIG_TARGET_TRIPLE)
	@echo "COPY $@"
	@cp $^ $@

.PHONY: phony-openlibm
phony-openlibm: include/$(CONFIG_TARGET_TRIPLE)
	@$(MAKE) -C openlibm \
		"CC=$(CC)" "CPPFLAGS=$(CFLAGS)" libopenlibm.a

openlibm/libopenlibm.a: phony-openlibm

ocaml:
	test ! -d $@
	cp -r "$$(ocamlfind query ocaml-src)" $@
	VERSION="$$(head -n1 ocaml/VERSION)" ; \
	if test -d "patches/$$VERSION" ; then \
	  git apply --directory=$@ "patches/$$VERSION"/*; \
	fi

ocaml/Makefile.config: $(TOOLCHAIN_FOR_BUILD) | ocaml
	PATH="$$PWD/bin/build:$$PATH" ; \
	cd ocaml && \
		./configure \
		--target="$(CONFIG_TARGET_TRIPLE)" \
		--prefix="$(CONFIG_SYSROOT)" \
		--disable-shared \
		--disable-systhreads \
		--disable-unix-lib \
		--disable-instrumented-runtime \
		--disable-debug-runtime \
		--disable-ocamltest \
		--disable-ocamldoc \
		--without-zstd \
		$(MAKECONF_OCAML_CONFIGURE_OPTIONS)

build:
	mkdir -p $@

OCAML_IS_BUILT := build/ocaml_is_built
$(OCAML_IS_BUILT): ocaml/Makefile.config | build
	PATH="$$PWD/bin/build/$(TOOLDIR_FOR_BUILD):$$PATH" $(MAKE) -C ocaml cross.opt
	cd ocaml && ocamlrun tools/stripdebug ocamlc ocamlc.tmp
	cd ocaml && ocamlrun tools/stripdebug ocamlopt ocamlopt.tmp
	touch $@

NOLIBC_CFLAGS= $(CFLAGS) \
							 -I $(TOPDIR)/nolibc/include \
							 -I $(TOPDIR)/openlibm/src \
							 -I $(TOPDIR)/openlibm/include

.PHONY: phony-nolibc
phony-nolibc: include/$(CONFIG_TARGET_TRIPLE)
	$(MAKE) -C nolibc libnolibc.a \
		"CC=$(CC)" "FREESTANDING_CFLAGS=$(NOLIBC_CFLAGS)"

nolibc/libnolibc.a: phony-nolibc

.PHONY: all
all: kernel/libgilbraltar.a

.PHONY: clean
clean:
	$(RM) -f kernel/*.o kernel/*.a *.elf *.bin *.img *.map
	$(RM) -rf include/$(CONFIG_TARGET_TRIPLE)/
	$(RM) -rf _build
	$(RM) -rf bin/
	$(RM) -rf lib/$(CONFIG_TARGET_TRIPLE)/
	if [ -d ocaml ] ; then $(MAKE) -C ocaml clean ; fi
	$(RM) -f test/*.o
	$(MAKE) -C openlibm clean
	$(MAKE) -C nolibc clean FREESTANDING_CFLAGS=_

.PHONY: distclean
distclean: clean
	$(RM) -f Makeconf Makeconf.sh
	if [ -d ocaml ] ; then $(MAKE) -C ocaml distclean ; fi

test/%.o: test/%.c
	@echo "CC $@"
	@$(CC) $(CFLAGS) -c -o $@ $<

kernel_2712.img: lib/$(CONFIG_TARGET_TRIPLE)/libgilbraltar.a lib/$(CONFIG_TARGET_TRIPLE)/libnolibc.a lib/$(CONFIG_TARGET_TRIPLE)/libopenlibm.a test/test.o
	@echo "LD ${@:img=elf}"
	@$(CC) test/test.o -o ${@:img=elf} $(CFLAGS) $(LDFLAGS) -Wl,-Map,${@:img=map} -T gilbraltar.ld
	@$(OBJCOPY) ${@:img=elf} -O binary $@