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

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

BUILD_DIR ?= build
COMMON_DIR ?= ../common
BSP_DIR ?= ../bsp
LINKER_SCRIPT ?= $(COMMON_DIR)/linker_ram.ld
MARCH ?= rv64imafdc_zicsr_zifencei
MABI ?= lp64d
BSP_UART_CLOCK_HZ ?= 100000000
BSP_UART_BAUDRATE ?= 460800
BSP_CLINT_TIMEBASE_HZ ?= 1000000
BSP_DTIM_BASE ?= 0x80000000
BSP_DTIM_SIZE ?= 0x00100000
CONFIG_STAMP := $(BUILD_DIR)/build_config.txt

# C sees BSP_DTIM_* while ld sees __dtim_*; both come from the same Makefile knobs.
CFLAGS ?= -march=$(MARCH) -mabi=$(MABI) -mcmodel=medany -Os -ffreestanding -fno-builtin -fno-common -Wall -Wextra -I$(BSP_DIR)/include -DBSP_UART_CLOCK_HZ=$(BSP_UART_CLOCK_HZ)UL -DBSP_UART_BAUDRATE=$(BSP_UART_BAUDRATE)UL -DBSP_CLINT_TIMEBASE_HZ=$(BSP_CLINT_TIMEBASE_HZ)UL -DBSP_DTIM_BASE=$(BSP_DTIM_BASE)UL -DBSP_DTIM_SIZE=$(BSP_DTIM_SIZE)UL
LDFLAGS ?= -T $(LINKER_SCRIPT) -nostartfiles -static -Wl,--gc-sections -Wl,--defsym=__dtim_base=$(BSP_DTIM_BASE) -Wl,--defsym=__dtim_size=$(BSP_DTIM_SIZE) -Wl,-Map,$(BUILD_DIR)/$(TARGET).map
LDLIBS ?= -Wl,--start-group -lc -lgcc -Wl,--end-group

APP_SRCS ?= main.c
BSP_SRCS ?= init.c uart.c plic.c irq.c spi_flash.c
APP_OBJS := $(addprefix $(BUILD_DIR)/,$(APP_SRCS:=.o))
COMMON_OBJS := $(BUILD_DIR)/common_start.S.o $(BUILD_DIR)/common_syscalls.c.o
BSP_OBJS := $(addprefix $(BUILD_DIR)/bsp_,$(BSP_SRCS:=.o))
OBJS := $(COMMON_OBJS) $(BSP_OBJS) $(APP_OBJS)
DEPS := $(OBJS:.o=.d)
DEPFLAGS := -MMD -MP

.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.$$$$"; \
	printf '%s\n' \
	  'MARCH=$(MARCH)' \
	  'MABI=$(MABI)' \
	  'BSP_UART_CLOCK_HZ=$(BSP_UART_CLOCK_HZ)' \
	  'BSP_UART_BAUDRATE=$(BSP_UART_BAUDRATE)' \
	  'BSP_CLINT_TIMEBASE_HZ=$(BSP_CLINT_TIMEBASE_HZ)' \
	  'BSP_DTIM_BASE=$(BSP_DTIM_BASE)' \
	  'BSP_DTIM_SIZE=$(BSP_DTIM_SIZE)' \
	  'GPS_DEBUG=$(GPS_DEBUG)' \
	  'GPS_DEBUG_LEVEL=$(GPS_DEBUG_LEVEL)' \
	  'CFLAGS=$(CFLAGS)' \
	  'LDFLAGS=$(LDFLAGS)' \
	  'LDLIBS=$(LDLIBS)' > "$$tmp"; \
	if ! cmp -s "$$tmp" "$@"; then mv "$$tmp" "$@"; else rm "$$tmp"; fi

FORCE:

$(BUILD_DIR)/common_start.S.o: $(COMMON_DIR)/start.S $(CONFIG_STAMP) | $(BUILD_DIR)
	mkdir -p $(dir $@)
	$(CC) $(CFLAGS) -c $< -o $@

$(BUILD_DIR)/common_syscalls.c.o: $(COMMON_DIR)/syscalls.c $(CONFIG_STAMP) | $(BUILD_DIR)
	mkdir -p $(dir $@)
	$(CC) $(CFLAGS) $(DEPFLAGS) -c $< -o $@

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

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

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

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

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

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

# Header-only firmware changes must invalidate their objects.  Without these
# generated dependencies, `debug-load` could silently reload an older ELF even
# though a configuration header had changed.
-include $(DEPS)

clean:
	rm -rf $(BUILD_DIR)