#############################################################
# Configuration
#############################################################

# Allow users to select a different cross compiler.
CROSS_COMPILE ?= riscv64-unknown-elf

# Allows users to create Makefile.local or ../Makefile.project with
# configuration variables, so they don't have to be set on the command-line
# every time.
extra_configs := $(wildcard Makefile.local ../Makefile.project)
ifneq ($(extra_configs),)
$(info Obtaining additional make variables from $(extra_configs))
include $(extra_configs)
endif

# Default target
BOARD ?= freedom-e300-hifive1
PROGRAM ?= demo_gpio
LINK_TARGET ?= flash
GDB_PORT ?= 3333

# Variables the user probably shouldn't override.
builddir := work/build

#############################################################
# BSP Loading
#############################################################

# Finds the directory in which this BSP is located, ensuring that there is
# exactly one.
board_dir := $(wildcard bsp/env/$(BOARD))
ifeq ($(words $(board_dir)),0)
$(error Unable to find BSP for $(BOARD), expected to find either "bsp/$(BOARD)" or "bsp-addons/$(BOARD)")
endif
ifneq ($(words $(board_dir)),1)
$(error Found multiple BSPs for $(BOARD): "$(board_dir)")
endif

# There must be a settings makefile fragment in the BSP's board directory.
ifeq ($(wildcard $(board_dir)/settings.mk),)
$(error Unable to find BSP for $(BOARD), expected to find $(board_dir)/settings.mk)
endif
include $(board_dir)/settings.mk

ifeq ($(RISCV_ARCH),)
$(error $(board_dir)/board.mk must set RISCV_ARCH, the RISC-V ISA string to target)
endif

ifeq ($(RISCV_ABI),)
$(error $(board_dir)/board.mk must set RISCV_ABI, the ABI to target)
endif

# Determines the XLEN from the toolchain tuple
ifeq ($(patsubst rv32%,rv32,$(RISCV_ARCH)),rv32)
RISCV_XLEN := 32
else ifeq ($(patsubst rv64%,rv64,$(RISCV_ARCH)),rv64)
RISCV_XLEN := 64
else
$(error Unable to determine XLEN from $(RISCV_ARCH))
endif

#############################################################
# Prints help message
#############################################################
.PHONY: help
help:
	@echo "  SiFive Freedom E Software Development Kit "
	@echo "  Makefile targets:"
	@echo ""
	@echo " software [PROGRAM=$(PROGRAM) BOARD=$(BOARD)]:"
	@echo "    Build a software program to load with the"
	@echo "    debugger."
	@echo ""
	@echo " clean [PROGRAM=$(PROGRAM) BOARD=$(BOARD)]:"
	@echo "    Clean compiled objects for a specified "
	@echo "    software program."
	@echo ""
	@echo " upload [PROGRAM=$(PROGRAM) BOARD=$(BOARD)]:"
	@echo "    Launch OpenOCD to flash your program to the"
	@echo "    on-board Flash."
	@echo ""
	@echo " run_openocd [BOARD=$(BOARD)]:"
	@echo " run_gdb     [PROGRAM=$(PROGRAM) BOARD=$(BOARD)]:"
	@echo "     Launch OpenOCD or GDB seperately. Allows Ctrl-C to halt running"
	@echo "     programs."
	@echo ""
	@echo " dasm [PROGRAM=$(PROGRAM)]:"
	@echo "     Generates the dissassembly output of 'objdump -D' to stdout."
	@echo ""
	@echo " For more information, visit dev.sifive.com"

#############################################################
# This section is for tool configuration
#############################################################

toolchain_builddir := $(builddir)/riscv-gnu-toolchain/riscv64-unknown-elf
toolchain_prefix := $(toolchain_builddir)/prefix

RISCV_PATH ?= $(toolchain_prefix)

RISCV_GCC     := $(abspath $(RISCV_PATH)/bin/$(CROSS_COMPILE)-gcc)
RISCV_GXX     := $(abspath $(RISCV_PATH)/bin/$(CROSS_COMPILE)-g++)
RISCV_OBJDUMP := $(abspath $(RISCV_PATH)/bin/$(CROSS_COMPILE)-objdump)
RISCV_GDB     := $(abspath $(RISCV_PATH)/bin/$(CROSS_COMPILE)-gdb)
RISCV_AR      := $(abspath $(RISCV_PATH)/bin/$(CROSS_COMPILE)-ar)

PATH := $(abspath $(RISCV_PATH)/bin):$(PATH)

#############################################################
# This Section is for Software Compilation
#############################################################
PROGRAM_DIR = software/$(PROGRAM)
PROGRAM_ELF = software/$(PROGRAM)/$(PROGRAM)

.PHONY: software_clean
clean: software_clean
software_clean:
	$(MAKE) -C $(PROGRAM_DIR) CC=$(RISCV_GCC) RISCV_ARCH=$(RISCV_ARCH) RISCV_ABI=$(RISCV_ABI) AR=$(RISCV_AR) BSP_BASE=$(abspath bsp) BOARD=$(BOARD) LINK_TARGET=$(LINK_TARGET) clean

.PHONY: software
software: software_clean
	$(MAKE) -C $(PROGRAM_DIR) CC=$(RISCV_GCC) RISCV_ARCH=$(RISCV_ARCH) RISCV_ABI=$(RISCV_ABI) AR=$(RISCV_AR) BSP_BASE=$(abspath bsp) BOARD=$(BOARD) LINK_TARGET=$(LINK_TARGET)

dasm: software $(RISCV_OBJDUMP)
	$(RISCV_OBJDUMP) -D $(PROGRAM_ELF)

#############################################################
# This Section is for uploading a program to SPI Flash
#############################################################
OPENOCDCFG ?= bsp/env/$(BOARD)/openocd.cfg
OPENOCDARGS += -f $(OPENOCDCFG)

GDB_UPLOAD_ARGS ?= --batch

GDB_UPLOAD_CMDS += -ex "set remotetimeout 240"
GDB_UPLOAD_CMDS += -ex "target extended-remote localhost:$(GDB_PORT)"
GDB_UPLOAD_CMDS += -ex "monitor reset halt"
GDB_UPLOAD_CMDS += -ex "monitor flash protect 0 64 last off"
GDB_UPLOAD_CMDS += -ex "load"
GDB_UPLOAD_CMDS += -ex "monitor resume"
GDB_UPLOAD_CMDS += -ex "monitor shutdown"
GDB_UPLOAD_CMDS += -ex "quit"

upload:
	$(RISCV_OPENOCD) $(OPENOCDARGS) & \
	$(RISCV_GDB) $(PROGRAM_DIR)/$(PROGRAM) $(GDB_UPLOAD_ARGS) $(GDB_UPLOAD_CMDS) && \
	echo "Successfully uploaded '$(PROGRAM)' to $(BOARD)."

#############################################################
# This Section is for launching the debugger
#############################################################

run_openocd:
	$(RISCV_OPENOCD) $(OPENOCDARGS)

GDBCMDS += -ex "set remotetimeout 240"
GDBCMDS += -ex "target extended-remote localhost:$(GDB_PORT)"

run_gdb:
	$(RISCV_GDB) $(PROGRAM_DIR)/$(PROGRAM) $(GDBARGS) $(GDBCMDS)