Makefile.loader

# When using Nuclei RISC-V Toolchain <= 2022.12
#CROSS_COMPILE ?= riscv-nuclei-elf-

# When using Nuclei RISC-V Toolchain >= 2023.10
# see https://github.com/riscv-mcu/riscv-gnu-toolchain/releases
CROSS_COMPILE ?= riscv64-unknown-elf-


TARGET ?= loader
ARCH ?= rv32
O ?= build
SPI ?= nuspi
FLASH ?= w25q256fv

CFLAGS := -nostdlib -nostartfiles -Wall -Os -fPIC -Wunused-result -g

ifeq ($(ARCH),rv32)
CFLAGS += -march=rv32e -mabi=ilp32e
else
CFLAGS += -march=rv64i -mabi=lp64
endif

## source control
C_SRCS := loader/loader.c
C_SRCS += spi/$(SPI).c
C_SRCS += flash/$(FLASH).c
ASM_SRCS := loader/startup.S

LINKER_SCRIPT := loader/riscv.lds

INCDIRS := flash loader spi

## extra options
CC      = $(CROSS_COMPILE)gcc
OBJCOPY = $(CROSS_COMPILE)objcopy
OBJDUMP = $(CROSS_COMPILE)objdump

CFLAGS += $(addprefix -I,$(sort $(INCDIRS)))

## output directory
OUTDIR := $(O)/$(ARCH)

## targets
LOADER_PREFIX := $(OUTDIR)/$(TARGET)
LOADER_ELF := $(LOADER_PREFIX).elf
LOADER_BIN := $(LOADER_PREFIX).bin

## objects
ASM_OBJS := $(addprefix $(OUTDIR)/, $(ASM_SRCS:=.o))
C_OBJS := $(addprefix $(OUTDIR)/, $(C_SRCS:=.o))

ALL_SRCS := $(C_SRCS) $(ASM_SRCS)
ALL_OBJS := $(ASM_OBJS) $(C_OBJS)
ALL_DEPS := $(ALL_OBJS:=.d)

MKDEP_OPT = -MMD -MT $@ -MF $@.d

all: $(LOADER_BIN)

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

.PHONY: clean all cleanall

$(LOADER_BIN): $(LOADER_ELF)
	$(OBJCOPY) -Obinary $< $@
	$(OBJDUMP) -S $< > $(LOADER_PREFIX).dasm

$(ALL_OBJS): $(OUTDIR)/%.o: %
	@mkdir -p $(@D)
	$(CC) -c $(CFLAGS) $(MKDEP_OPT) -o $@ $<

$(LOADER_ELF): $(ALL_OBJS)
	$(CC) $(CFLAGS) -T $(LINKER_SCRIPT) $^ -o $@

clean:
	rm -rf $(OUTDIR)

cleanall:
	rm -rf $(O)