Makefile

CROSS_COMPILE ?= riscv64-unknown-elf-
CC:=$(CROSS_COMPILE)gcc
AS:=$(CROSS_COMPILE)as
LD:=$(CROSS_COMPILE)ld
OBJCOPY:=$(CROSS_COMPILE)objcopy
OBJDUMP:=$(CROSS_COMPILE)objdump
READELF:=$(CROSS_COMPILE)readelf

ifneq ($(MAKECMDGOALS), clean)
ifeq ($(PLAT),)
$(error Undefined platform)
endif
endif

build_dir:=build/$(PLAT)
plat_dir:=platform/$(PLAT)
asm_dir:=src/asm
TARGET := $(build_dir)/rv_iommu_test

ifeq ($(wildcard $(plat_dir)),)
$(error unsupported platform $(PLAT))
else
$(shell mkdir -p $(build_dir))
endif

prev_log_file:=$(build_dir)/prev_log.mk
-include $(prev_log_file)
LOG_LEVEL := LOG_INFO
GENERIC_FLAGS += -D LOG_LEVEL=$(LOG_LEVEL)
$(file > $(prev_log_file), PREV_LOG_LEVEL:=$(LOG_LEVEL))
ifneq ($(PREV_LOG_LEVEL), $(LOG_LEVEL))
pre_targets += clean_objs
endif

# Include all architecture-related C source files
c_srcs = $(wildcard src/*.c)
# Include all platform-related C source files
c_srcs += $(wildcard $(plat_dir)/*.c)

# Include all architecture-related assembly source files
asm_srcs := $(wildcard $(asm_dir)/*.S) $(wildcard $(plat_dir)/*.S)
# Include all platform-related assembly source files
asm_srcs += $(wildcard $(plat_dir)/*.S)

ld_file:=linker.ld

inc_dirs := ./src/inc $(plat_dir)/inc
inc_dirs := $(addprefix -I, $(inc_dirs))

objs:=
objs+=$(patsubst  %.c, $(build_dir)/%.o, $(c_srcs))
objs+=$(patsubst  %.S, $(build_dir)/%.o, $(asm_srcs))
ld_file_final:=$(build_dir)/$(ld_file)

deps:=$(patsubst  %.o, %.d, $(objs)) $(ld_file_final).d
dirs:=$(sort $(dir $(objs) $(deps)))

GENERIC_FLAGS += -march=rv64imac -mabi=lp64 -g3 -mcmodel=medany -O3 $(inc_dirs)
ASFLAGS = $(GENERIC_FLAGS)
CFLAGS = $(GENERIC_FLAGS)
LDFLAGS = -ffreestanding -nostartfiles -static $(GENERIC_FLAGS)

all: $(pre_targets) $(TARGET).bin

$(TARGET).bin: $(TARGET).elf
	$(OBJCOPY) -O binary $< $@

$(TARGET).elf: $(objs) $(ld_file_final)
	$(CC) $(LDFLAGS) -T$(ld_file_final) $(objs) -o $@
	$(OBJDUMP) -S $@ > $(TARGET).asm
	$(READELF) -a -W $@ > $(@).txt

$(build_dir)/%.o: %.[c,S] $(build_dir)/%.d
	$(CC) $(CFLAGS) -c $< -o $@

$(build_dir)/%.d: %.[c,S,ld] 
	$(CC) $(GENERIC_FLAGS) -MM -MT "$(patsubst %.d, %.o, $@) $@" -MF $@ $<  

$(ld_file_final): $(ld_file)
	$(CC) $(CFLAGS) -E -x assembler-with-cpp $< | grep "^[^#;]" > $@
	
.SECONDEXPANSION:

$(objs) $(deps): | $$(@D)/

$(dirs):
	mkdir -p $@

ifneq ($(MAKECMDGOALS), clean)
-include $(deps)
endif

clean:
	rm -rf $(build_dir)

clean_objs:
	rm -rf $(build_dir)/**.o

.PHONY: all clean