REPO_DIR ?= $(abspath ../../..)
include $(REPO_DIR)/tools/project.mk

CC := $(CROSS)gcc
OBJCOPY := $(CROSS)objcopy
OBJDUMP := $(CROSS)objdump
SIZE := $(CROSS)size

BUILD_DIR := build
TARGET := bootloader
BSP_DIR := ../bsp
APP_FLASH_OFFSET ?= 0x06000000
MARCH ?= rv64imafdc_zicsr_zifencei
MABI ?= lp64d
BSP_UART_CLOCK_HZ ?= 100000000
BSP_UART_BAUDRATE ?= 115200
BSP_DTIM_BASE ?= 0x80000000
BSP_DTIM_SIZE ?= 0x00100000
CONFIG_STAMP := $(BUILD_DIR)/build_config.txt

# C uses BSP_DTIM_* for bounds checks; linker uses __dtim_* for RAM origin/length.
CFLAGS := -march=$(MARCH) -mabi=$(MABI) -mcmodel=medany -Os -ffreestanding -fno-builtin -fno-common -Wall -Wextra -I$(BSP_DIR)/include -DAPP_FLASH_OFFSET=$(APP_FLASH_OFFSET)UL -DBSP_UART_CLOCK_HZ=$(BSP_UART_CLOCK_HZ)UL -DBSP_UART_BAUDRATE=$(BSP_UART_BAUDRATE)UL -DBSP_DTIM_BASE=$(BSP_DTIM_BASE)UL -DBSP_DTIM_SIZE=$(BSP_DTIM_SIZE)UL
LDFLAGS := -T linker.ld -nostdlib -static -Wl,--gc-sections -Wl,--defsym=__dtim_base=$(BSP_DTIM_BASE) -Wl,--defsym=__dtim_size=$(BSP_DTIM_SIZE) -Wl,-Map,$(BUILD_DIR)/$(TARGET).map

SRCS := start.S main.c
BSP_SRCS := init.c uart.c spi_flash.c
OBJS := $(addprefix $(BUILD_DIR)/,$(SRCS:=.o)) $(addprefix $(BUILD_DIR)/bsp_,$(BSP_SRCS:=.o))

.PHONY: all clean FORCE

all: $(BUILD_DIR)/$(TARGET).elf $(BUILD_DIR)/$(TARGET).img $(BUILD_DIR)/$(TARGET).dump
	$(SIZE) $(BUILD_DIR)/$(TARGET).elf

$(BUILD_DIR):
	mkdir -p $@

$(CONFIG_STAMP): FORCE | $(BUILD_DIR)
	@tmp="$@.tmp"; \
	printf '%s\n' \
	  'APP_FLASH_OFFSET=$(APP_FLASH_OFFSET)' \
	  'MARCH=$(MARCH)' \
	  'MABI=$(MABI)' \
	  'BSP_UART_CLOCK_HZ=$(BSP_UART_CLOCK_HZ)' \
	  'BSP_UART_BAUDRATE=$(BSP_UART_BAUDRATE)' \
	  'BSP_DTIM_BASE=$(BSP_DTIM_BASE)' \
	  'BSP_DTIM_SIZE=$(BSP_DTIM_SIZE)' > "$$tmp"; \
	if ! cmp -s "$$tmp" "$@"; then mv "$$tmp" "$@"; else rm "$$tmp"; fi

FORCE:

$(BUILD_DIR)/%.S.o: %.S $(CONFIG_STAMP) | $(BUILD_DIR)
	$(CC) $(CFLAGS) -c $< -o $@

$(BUILD_DIR)/%.c.o: %.c $(CONFIG_STAMP) | $(BUILD_DIR)
	$(CC) $(CFLAGS) -c $< -o $@

$(BUILD_DIR)/bsp_%.c.o: $(BSP_DIR)/drivers/%.c $(CONFIG_STAMP) | $(BUILD_DIR)
	$(CC) $(CFLAGS) -c $< -o $@

$(BUILD_DIR)/$(TARGET).elf: $(OBJS) linker.ld $(CONFIG_STAMP)
	$(CC) $(CFLAGS) $(OBJS) $(LDFLAGS) -o $@

$(BUILD_DIR)/$(TARGET).img: $(BUILD_DIR)/$(TARGET).elf
	$(OBJCOPY) -O binary $< $@

$(BUILD_DIR)/$(TARGET).dump: $(BUILD_DIR)/$(TARGET).elf
	$(OBJDUMP) -d -S $< > $@

clean:
	rm -rf $(BUILD_DIR)