rules.mk

# This version of rules.mk expects the following to be defined before
# inclusion..
### REQUIRED ###
# OPENCM3_DIR - duh
# PROJECT - will be the basename of the output elf, eg usb-gadget0-stm32f4disco
# CFILES - basenames only, eg main.c blah.c
# CXXFILES - same for C++ files. Must have cxx suffix!
# DEVICE - the full device name, eg stm32f405ret6
#  _or_
# LDSCRIPT - full path, eg ../../examples/stm32/f4/stm32f4-discovery/stm32f4-discovery.ld
# OPENCM3_LIB - the basename, eg: opencm3_stm32f4
# OPENCM3_DEFS - the target define eg: -DSTM32F4
# ARCH_FLAGS - eg, -mthumb -mcpu=cortex-m4 -mfloat-abi=hard -mfpu=fpv4-sp-d16
#    (ie, the full set of cpu arch flags, _none_ are defined in this file)
#
### OPTIONAL ###
# INCLUDES - fully formed -I paths, if you want extra, eg -I../shared
# BUILD_DIR - defaults to bin, should set this if you are building multiarch
# OPT - full -O flag, defaults to -Os
# CSTD - defaults -std=c99
# CXXSTD - no default.
# OOCD_INTERFACE - eg stlink-v2
# OOCD_TARGET - eg stm32f4x
#    both only used if you use the "make flash" target.
# OOCD_FILE - eg my.openocd.cfg
#    This overrides interface/target above, and is used as just -f FILE
### TODO/FIXME/notes ###
# No support for stylecheck.
# No support for BMP/texane/random flash methods, no plans either
# No support for magically finding the library.
# C++ hasn't been actually tested with this..... sorry bout that. ;)
# Second expansion/secondary not set, add this if you need them.

BUILD_DIR ?= bin
OPT ?= -O2
CSTD ?= -std=c11
CXXSTD ?= -std=c++17

# Be silent per default, but 'make V=1' will show all compiler calls.
# If you're insane, V=99 will print out all sorts of things.
V?=0
ifeq ($(V),0)
Q	:= @
NULL	:= 2>/dev/null
endif

# Tool paths.
PREFIX	?= arm-none-eabi-
GDB	= $(PREFIX)gdb
CC	= $(PREFIX)gcc
CXX	= $(PREFIX)g++
LD	= $(PREFIX)gcc
OBJCOPY	= $(PREFIX)objcopy
OBJDUMP	= $(PREFIX)objdump
OOCD	?= openocd

OPENCM3_INC = $(OPENCM3_DIR)/include

# Inclusion of library header files
INCLUDES += $(patsubst %,-I%, . $(OPENCM3_INC) )

OBJS = $(CFILES:%.c=$(BUILD_DIR)/%.o)
OBJS += $(CXXFILES:%.cpp=$(BUILD_DIR)/%.o)
OBJS += $(AFILES:%.S=$(BUILD_DIR)/%.o)
GENERATED_BINS = $(PROJECT).elf $(PROJECT).bin $(PROJECT).old.elf $(PROJECT).map $(PROJECT).list $(PROJECT).lss

TGT_CPPFLAGS += -MD -flto
TGT_CPPFLAGS += -Wall -Wundef $(INCLUDES)
TGT_CPPFLAGS += $(INCLUDES) $(OPENCM3_DEFS)

TGT_CFLAGS += $(OPT) $(CSTD) -ggdb3
TGT_CFLAGS += $(ARCH_FLAGS)
TGT_CFLAGS += -fno-common
TGT_CFLAGS += -ffunction-sections -fdata-sections
TGT_CFLAGS += -Wextra -Wshadow -Wno-unused-variable -Wimplicit-function-declaration
TGT_CFLAGS += -Wredundant-decls -Wstrict-prototypes -Wmissing-prototypes

TGT_CXXFLAGS += $(OPT) $(CXXSTD) -ggdb3 -fno-exceptions -fno-use-cxa-atexit -fno-rtti
TGT_CXXFLAGS += $(ARCH_FLAGS)
TGT_CXXFLAGS += -fno-common
TGT_CXXFLAGS += -ffunction-sections -fdata-sections
TGT_CXXFLAGS += -Wextra -Wshadow -Wredundant-decls -Weffc++

TGT_ASFLAGS += $(OPT) $(ARCH_FLAGS) -ggdb3

TGT_LDFLAGS += -T$(LDSCRIPT) -L$(OPENCM3_DIR)/lib -nostartfiles
TGT_LDFLAGS += $(ARCH_FLAGS)
TGT_LDFLAGS += -specs=nano.specs
TGT_LDFLAGS += -u _printf_float
TGT_LDFLAGS += -Wl,--gc-sections
# OPTIONAL
#TGT_LDFLAGS += -Wl,-Map=$(PROJECT).map
ifeq ($(V),99)
TGT_LDFLAGS += -Wl,--print-gc-sections
endif

# Linker script generator fills this in for us.
ifeq (,$(DEVICE))
LDLIBS += -l$(OPENCM3_LIB)
endif
# nosys is only in newer gcc-arm-embedded...
#LDLIBS += -specs=nosys.specs
LDLIBS += -Wl,--start-group -lc_nano -lgcc -lnosys -Wl,--end-group
#LDLIBS += -Wl,--start-group -nostdlib -lgcc -lnosys -Wl,--end-group

# Burn in legacy hell fortran modula pascal yacc idontevenwat
.SUFFIXES:
.SUFFIXES: .c .S .h .o .cxx .cpp .elf .bin .list .lss

# Bad make, never *ever* try to get a file out of source control by yourself.
%: %,v
%: RCS/%,v
%: RCS/%
%: s.%
%: SCCS/s.%

all: $(PROJECT).elf $(PROJECT).bin
flash: $(PROJECT).flash

# error if not using linker script generator
ifeq (,$(DEVICE))
$(LDSCRIPT):
ifeq (,$(wildcard $(LDSCRIPT)))
    $(error Unable to find specified linker script: $(LDSCRIPT))
endif
else
# if linker script generator was used, make sure it's cleaned.
GENERATED_BINS += $(LDSCRIPT)
endif

# Need a special rule to have a bin dir
$(BUILD_DIR)/%.o: %.c
	@printf "  CC\t$<\n"
	@mkdir -p $(dir $@)
	$(Q)$(CC) $(TGT_CFLAGS) $(CFLAGS) $(TGT_CPPFLAGS) $(CPPFLAGS) -o $@ -c $<

$(BUILD_DIR)/%.o: %.cpp
	@printf "  CXX\t$<\n"
	@mkdir -p $(dir $@)
	$(Q)$(CXX) $(TGT_CXXFLAGS) $(CXXFLAGS) $(TGT_CPPFLAGS) $(CPPFLAGS) -o $@ -c $<

$(BUILD_DIR)/%.o: %.S
	@printf "  AS\t$<\n"
	@mkdir -p $(dir $@)
	$(Q)$(CC) $(TGT_ASFLAGS) $(ASFLAGS) $(TGT_CPPFLAGS) $(CPPFLAGS) -o $@ -c $<

$(PROJECT).elf: $(OBJS) $(LDSCRIPT) $(LIBDEPS)
	@printf "  LD\t$@\n"
	$(Q)$(LD) $(TGT_LDFLAGS) $(LDFLAGS) $(OBJS) $(LDLIBS) -o $@

%.bin: %.elf
	@printf "  OBJCOPY\t$@\n"
	$(Q)$(OBJCOPY) -O binary  $< $@

%.lss: %.elf
	$(OBJDUMP) -h -S $< > $@

%.list: %.elf
	$(OBJDUMP) -S $< > $@

%.flash: %.elf
	@printf "  FLASH\t$<\n"
ifeq (,$(OOCD_FILE))
	$(Q)(echo "halt; program $(realpath $(*).elf) verify reset" | nc -4 localhost 4444 2>/dev/null) || \
		$(OOCD) -f interface/$(OOCD_INTERFACE).cfg \
		-f target/$(OOCD_TARGET).cfg \
		-c "program $(realpath $(*).elf) verify reset exit" \
		$(NULL)
else
	$(Q)(echo "halt; program $(realpath $(*).elf) verify reset" | nc -4 localhost 4444 2>/dev/null) || \
		$(OOCD) -f $(OOCD_FILE) \
		-c "program $(realpath $(*).elf) verify reset exit" \
		$(NULL)
endif

clean:
	rm -rf $(BUILD_DIR) $(GENERATED_BINS)

.PHONY: all clean flash
-include $(OBJS:.o=.d)