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
# 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_BASE = build
BUILD_DIR = $(BUILD_BASE)/$(DEVICE)
OPT ?= -Os
CSTD ?= -std=c99

CDEFS ?=
CXXDEFS ?=

# 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-
CC	= $(PREFIX)gcc
LD	= $(PREFIX)gcc
OBJCOPY	= $(PREFIX)objcopy
OBJDUMP	= $(PREFIX)objdump
OOCD	?= openocd

# Configure path to gdb
GDB ?=

# Use gdb-multiarch if it's present
ifndef GDB
	GDB = $(shell command -v gdb-multiarch 2> /dev/null)
endif

# Otherwise assume prefixed gdb
ifndef GDB
	GDB = $(PREFIX)gdb
endif

# Filename to build to
OUTPUT_ELF = $(PROJECT).$(DEVICE).elf
OUTPUT_BIN = $(PROJECT).$(DEVICE).bin

OPENCM3_INC = $(OPENCM3_DIR)/include

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

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

TGT_CPPFLAGS += -MD
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 -Wno-unused-function -Wimplicit-function-declaration
TGT_CFLAGS += -Wredundant-decls -Wstrict-prototypes -Wmissing-prototypes
TGT_CFLAGS += $(CDEFS)

TGT_CXXFLAGS += $(OPT) $(CXXSTD) -ggdb3
TGT_CXXFLAGS += $(ARCH_FLAGS)
TGT_CXXFLAGS += -fno-common
TGT_CXXFLAGS += -ffunction-sections -fdata-sections
TGT_CXXFLAGS += -Wextra -Wshadow -Wredundant-decls  -Weffc++
TGT_CXXFLAGS += $(CXXDEFS)

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

TGT_LDFLAGS += -T$(LDSCRIPT) -L$(OPENCM3_DIR)/lib -nostartfiles
TGT_LDFLAGS += $(ARCH_FLAGS)
TGT_LDFLAGS += -specs=nano.specs
TGT_LDFLAGS += -Wl,--gc-sections
# OPTIONAL
#TGT_LDFLAGS += -Wl,-Map=$(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 -lgcc -lnosys -Wl,--end-group

# Burn in legacy hell fortran modula pascal yacc idontevenwat
.SUFFIXES:
.SUFFIXES: .c .S .h .o .cxx .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: $(OUTPUT_ELF) $(OUTPUT_BIN)

# 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 $<

$(BUILD_DIR)/%.o: %.cxx
	@printf "  CXX\t$<\n"
	@mkdir -p $(dir $@)
	$(Q)$(CC) $(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 $<

$(OUTPUT_ELF): opencm3 $(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  $< $@

	@printf "\nFirmware size ($<):\n"
	@./scripts/size.sh $< $(FLASH_SIZE_BYTES) $(SRAM_SIZE_BYTES)

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

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

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

.PHONY: all clean opencm3
-include $(OBJS:.o=.d)