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Makefile Analysis

代码小A5/20/26About 8 minK230K230RT-Smart

Makefile Analysis

Taking some real code as examples:

Case 1

ifneq ($(MKENV_INCLUDED),1)
include mkenv.mk
endif

subdirs-y :=
include apps.mk

.PHONY: all clean distclean

all: $(subdirs-y)
	@echo "Make Applications done."

ifneq ($(strip $(subdirs-y)),)
.PHONY: $(subdirs-y)

$(subdirs-y):
	@echo "[BUILD] applications $@"
	@$(MAKE) -C $@ all || exit $?;
endif

clean:
	@if [ -n "$(subdirs-y)" ]; then \
		for dir in $(subdirs-y); do \
			echo "[CLEAN] applications $$dir"; \
			$(MAKE) -C $$dir clean || exit $?; \
		done; \
	fi

distclean: clean
	@if [ -n "$(subdirs-y)" ]; then \
		for dir in $(subdirs-y); do \
			echo "[DISTCLEAN] applications $$dir"; \
			$(MAKE) -C $$dir distclean || exit $?; \
		done; \
	fi

.PHONY: gen_kconfig
gen_kconfig:
	@echo "# Dynamic generate by Makefile, DO NOT Modify it.\n" > $(SDK_BUILD_DIR)/Kconfig.app; \
	for dir in $(shell find $(SDK_APPS_SRC_DIR) -maxdepth 1 -mindepth 1 -type d); do \
		echo "source \"$$dir/Kconfig\"" >> $(SDK_BUILD_DIR)/Kconfig.app; \
	done; \

ifneq ($(MKENV_INCLUDED),1) is used to check whether the variable MKENV_INCLUDED is 11; if it is 1, then include mkenv.mk, which prevents multiple files from including mkenv.mk repeatedly during compilation.
It defines the variable subdirs-y (-y is a Linux naming convention, meaning a subdirectory that is included in the build),

subdirs-y :=
include apps.mk

The contents of apps.mk are as follows:

-include $(SDK_SRC_ROOT_DIR)/.config

subdirs-$(CONFIG_APP_ENABLE_HELLOWORLD) += helloworld
subdirs-$(CONFIG_APP_ENABLE_POKEMON_DETECT) += pokemon_detect

Case 2:

# Include base configuration
include ../mkenv.mk
include $(SDK_RTSMART_SRC_DIR)/libs/mk/toolchain_riscv64_musl.mk

# Build configuration
DIR 	:= $(shell basename `pwd`)
BUILD	:= $(SDK_APPS_BUILD_DIR)/$(DIR)
BIN 	:= $(SDK_APPS_IMAGE_DIR)/$(DIR)

# Source files handling
SRC_DIRS  := . screens

SRCS 	:= $(shell find $(SRC_DIRS) -maxdepth 1 -type f \( -name "*.c" -o -name "*.cpp" -o -name "*.cc" \))
OBJS	:= $(addprefix $(BUILD)/, $(addsuffix .o, $(basename $(notdir $(SRCS)))))
DEPS	:= $(OBJS:.o=.d)

# Directory creation logic - Captured and sorted
OBJ_DIRS  := $(sort $(dir $(OBJS) $(BIN)))

# Library configuration
include $(SDK_RTSMART_SRC_DIR)/libs/mk/liblvgl.mk
include $(SDK_RTSMART_SRC_DIR)/libs/mk/libmpp.mk
include $(SDK_RTSMART_SRC_DIR)/libs/mk/libopencv.mk
include $(SDK_RTSMART_SRC_DIR)/libs/mk/libnncase.mk
include $(SDK_RTSMART_SRC_DIR)/libs/mk/librtsmart_hal.mk
include $(SDK_RTSMART_SRC_DIR)/libs/mk/lib3rdparty.mk



# Compiler flags
C_CXX_FLAGS := -fopenmp -march=rv64imafdcv -mabi=lp64d -mcmodel=medany -Os
C_CXX_FLAGS += -I. $(LIB_CFLAGS) -I$(SDK_SRC_ROOT_DIR)/include -include "generated/autoconf.h"
C_CXX_FLAGS += -DLV_LVGL_H_INCLUDE_SIMPLE
C_CXX_FLAGS += -Wall -Wextra -ffunction-sections -fdata-sections

CFLAGS 		:= $(C_CXX_FLAGS) -std=gnu99
CXX_FLAGS 	:= $(C_CXX_FLAGS)

# Linker flags
LDFLAGS := -T $(SDK_RTSMART_SRC_DIR)/libs/mk/link.lds --static -Wl,--gc-sections
LDFLAGS += $(LIB_LDFLAGS)

# Phony targets
.PHONY: all clean distclean

all: $(BIN)
	@$(ECHO) [BUILD] applications $(DIR) done.

.PHONY: .FORCE
.FORCE:

# Rule to link the final ELF - Order-only dependency on directory
$(BIN): $(OBJS) .FORCE | $(OBJ_DIRS)
	@echo "[LD] $@"
	$(Q)$(CXX) $(CFLAGS) $(OBJS) $(LDFLAGS) -o $@
	$(Q)$(STRIP) $@

# Rule for C objects - Order-only dependency on directory
vpath %.c $(SRC_DIRS)
$(BUILD)/%.o: %.c | $(OBJ_DIRS)
	@echo "[CC] $@"
	$(Q)$(CC) $(CFLAGS) -MD -MP -MF $(@:.o=.d) -c $< -o $@

# Rule for C++ objects - Order-only dependency on directory
vpath %.cc $(SRC_DIRS)
$(BUILD)/%.o: %.cc | $(OBJ_DIRS)
	@echo "[CXX] $@"
	$(Q)$(CXX) $(CXX_FLAGS) -MD -MP -MF $(@:.o=.d) -c $< -o $@

vpath %.cpp $(SRC_DIRS)
$(BUILD)/%.o: %.cpp | $(OBJ_DIRS)
	@echo "[CXX] $@"
	$(Q)$(CXX) $(CXX_FLAGS) -MD -MP -MF $(@:.o=.d) -c $< -o $@

# Actual directory creation rule
$(OBJ_DIRS):
	$(Q)mkdir -p $@

clean:
	@rm -rf $(BIN)

distclean: clean
	@rm -rf $(BUILD)

-include $(DEPS)

Explanation:

# Include base configuration
include ../mkenv.mk
include $(SDK_RTSMART_SRC_DIR)/libs/mk/toolchain_riscv64_musl.mk

include is used to import files, just like in C — include ../mkenv.mk is equivalent to placing the contents of mkenv.mk at that position.
The contents of mkenv.mk are as follows:

ifneq ($(MKENV_INCLUDED),1)
export SDK_SRC_ROOT_DIR := $(realpath $(dir $(realpath $(lastword $(MAKEFILE_LIST))))/../../)
endif

include $(SDK_SRC_ROOT_DIR)/tools/mkenv.mk

include $(SDK_SRC_ROOT_DIR)/.config

export SDK_APPS_IMAGE_DIR := $(SDK_BUILD_IMAGES_DIR)/sdcard/app/

export MKENV_INCLUDED_APPLICATIONS=1

In the code above:

ifneq ($(MKENV_INCLUDED),1)
...
endif

is used to prevent the file from being included more than once. export SDK_SRC_ROOT_DIR := $(realpath $(dir $(realpath $(lastword $(MAKEFILE_LIST))))/../../) is a very classic and advanced Makefile idiom for "getting the project's absolute root path". To understand it, we need to peel it apart from the inside out, like an onion:

  1. $(MAKEFILE_LIST): this is a built-in Make variable that records the list of names of all Makefiles loaded so far — right now it holds MakeFile ../mkenv.mk.
  2. lastword: takes the last word of that list. Since the system just loaded the current ../mkenv.mk, what it gets is the name of this file itself (including the relative path).
  3. realpath (inner): converts the name just obtained into an absolute path (and resolves symlinks along the way). For example, it becomes /home/fs/workspace/K230/rtos/src/applications/mkenv.mk.
  4. dir: extracts the directory path where this file lives. The result becomes /home/fs/workspace/K230/rtos/src/applications
  5. /../../: goes up two levels from that directory. It becomes `/home/fs/workspace/K230/rtos/../../
  6. realpath (outer): finally normalizes the absolute path one more time, erasing the .. relative marker, and ends up with the clean SDK root directory: /home/fs/workspace/K230/rtos.
  • export: declares the computed SDK_SRC_ROOT_DIR as an environment variable, so that every subsequently invoked sub-Makefile or shell script can use this variable directly, and nobody has to guess relative paths anymore.
    Next, include $(SDK_SRC_ROOT_DIR)/tools/mkenv.mk — that is, it includes /home/fs/workspace/K230/rtos/tools/mkenv.mk
export SDK_TOOLCHAIN_DIR?=$(shell echo $$HOME)/.kendryte/k230_toolchains
export SDK_TOOLS_DIR=$(SDK_SRC_ROOT_DIR)/tools

# Default target
.DEFAULT_GOAL := all

# Strip quotes and then whitespaces
qstrip = $(strip $(subst ",,$(1)))

define check_build_dir
$(shell \
  if [ ! -d $(1) ]; then \
    mkdir -p $(1); \
  fi; \
)
endef

define del_mark
$(shell find $(SDK_SRC_ROOT_DIR) -type f -name ".parse_config" | xargs rm -rf {})
endef

# 1 src
# 2 dst
define sync_dir
	@echo "Source: $(1)"
	@echo "Destination: $(2)"
	@rm -rf $(2)/*
	@mkdir -p $(2) || exit 1
	@rsync -aq --delete $(1)/ $(2)/
endef

define gen_kconfig
@if [ -f "$(1)/Kconfig" ]; then \
    cp -f $(1)/Kconfig $(SDK_BUILD_DIR)/Kconfig.$(2); \
else \
    echo "" > $(SDK_BUILD_DIR)/Kconfig.$(2); \
fi
endef

# Do not print "Entering directory ...",
# but we want to display it when entering to the output directory
# so that IDEs/editors are able to understand relative filenames.
MAKEFLAGS += --no-print-directory

# ifneq ($(MKENV_INCLUDED),1)
#   JOBS := $(shell ps -o args= $(MAKEPPID) | grep -o -E -- '-j[0-9]+' | head -n 1 | cut -c3-)
#   ifneq ($(JOBS),)
#     ifneq ($(JOBS),1)
#       $(error not support parallel build now)
#     endif
#   endif
# endif

# Turn on increased build verbosity by defining BUILD_VERBOSE in your main
# Makefile or in your environment. You can also use V=1 on the make command
# line.

ifeq ("$(origin V)", "command line")
BUILD_VERBOSE=$(V)
endif

ifndef BUILD_VERBOSE
BUILD_VERBOSE = 0
endif
ifeq ($(BUILD_VERBOSE),0)
Q = @
else
Q =
endif

RM = rm -rf
ECHO = echo
CP = cp
MKDIR = mkdir
SED = sed
CAT = cat
TOUCH = touch
PYTHON = python3
ZIP = zip
INSTALL = install

# Check if 'bear' command exists
BEAR_EXISTS := $(shell command -v bear >/dev/null 2>&1 && echo yes || echo no)

BEAR_COMMAND ?= bear

ifeq ($(BEAR_EXISTS),yes)
  # Capture the Bear version
  BEAR_VERSION := $(shell bear --version | grep -oE '[0-9]+\.[0-9]+\.[0-9]+')

  # Convert BEAR_VERSION to a single integer and compare it to 30000
  BEAR_VERSION_INT := $(shell echo $(BEAR_VERSION) | awk -F. '{print ($$1*10000 + $$2*100 + $$3)}')

  # Check if the Bear version is 3.0.0 or greater
  ifneq ($(shell [ $(BEAR_VERSION_INT) -ge 30000 ] && echo true),)
      BEAR_COMMAND := bear --
  endif
endif

export BEAR_COMMAND

PARALLEL ?= $(shell if command -v nproc > /dev/null 2>&1; then nproc; \
            elif [ -f /proc/cpuinfo ]; then grep -c '^processor' /proc/cpuinfo; \
            elif command -v sysctl > /dev/null 2>&1; then sysctl -n hw.ncpu; \
            else echo 1; fi)

export NCPUS?=$(PARALLEL)

CONFIG_SDK_ENABLE_CANMV ?= n

def_config :=$(filter %_defconfig,$(MAKECMDGOALS))
ifneq ($(def_config),)
  ifeq ($(shell if [ -f $(SDK_SRC_ROOT_DIR)/configs/$(def_config) ]; then echo 1; else echo 0; fi;), 0)
    $(error "Please specify a valid CONFIG")
  endif

  CONFIG_BOARD_CONFIG_NAME := $(def_config)
else
  -include $(SDK_SRC_ROOT_DIR)/.config
endif

CONFIG_BOARD := $(call qstrip,$(CONFIG_BOARD))

export CONFIG_SDK_ENABLE_CANMV

ifeq ($(strip $(filter $(MAKECMDGOALS),list_def list-def dl_toolchain)),)
  ifeq ($(CONFIG_BOARD_CONFIG_NAME),)
    $(error "Please run make xxx_defconfig first. Use 'make list-def' to see available configurations.")
  endif
endif

MK_LIST_DEFCONFIG?=$(CONFIG_BOARD_CONFIG_NAME)
export MK_LIST_DEFCONFIG

export UBOOT_DEFCONFIG=$(patsubst %,%_defconfig,$(call qstrip,$(CONFIG_UBOOT_CONFIG_FILE)))
export RTSMART_DEFCONFIG=$(patsubst %,%_defconfig,$(call qstrip,$(CONFIG_RTSMART_CONFIG_FILE)))

export SDK_BOARDS_DIR=$(SDK_SRC_ROOT_DIR)/boards
export SDK_BOARD_DIR=$(SDK_BOARDS_DIR)/$(call qstrip,$(CONFIG_BOARD))

export SDK_OPENSBI_SRC_DIR=$(SDK_SRC_ROOT_DIR)/src/opensbi
export SDK_RTSMART_SRC_DIR=$(SDK_SRC_ROOT_DIR)/src/rtsmart
export SDK_UBOOT_SRC_DIR=$(SDK_SRC_ROOT_DIR)/src/uboot
export SDK_CANMV_SRC_DIR=$(SDK_SRC_ROOT_DIR)/src/canmv
export SDK_APPS_SRC_DIR=$(SDK_SRC_ROOT_DIR)/src/applications

export SDK_BUILD_DIR=$(SDK_SRC_ROOT_DIR)/output/$(call qstrip,$(CONFIG_BOARD_CONFIG_NAME))

export SDK_OPENSBI_BUILD_DIR=$(SDK_BUILD_DIR)/opensbi
export SDK_RTSMART_BUILD_DIR=$(SDK_BUILD_DIR)/rtsmart
export SDK_UBOOT_BUILD_DIR=$(SDK_BUILD_DIR)/uboot
export SDK_CANMV_BUILD_DIR=$(SDK_BUILD_DIR)/canmv
export SDK_APPS_BUILD_DIR=$(SDK_BUILD_DIR)/applications

export SDK_ARDUINO_SDK_BUILD_DIR=$(SDK_SRC_ROOT_DIR)/output/arduino-sdk

export SDK_BUILD_IMAGES_DIR=$(SDK_BUILD_DIR)/images

ifeq ($(strip $(filter $(MAKECMDGOALS),list_def list-def dl_toolchain)),)
  $(call check_build_dir, $(SDK_BUILD_IMAGES_DIR))

  $(call check_build_dir, $(SDK_OPENSBI_BUILD_DIR))
  $(call check_build_dir, $(SDK_RTSMART_BUILD_DIR))
  $(call check_build_dir, $(SDK_UBOOT_BUILD_DIR))
  $(call check_build_dir, $(SDK_CANMV_BUILD_DIR))
  $(call check_build_dir, $(SDK_APPS_BUILD_DIR))
  $(call check_build_dir, $(SDK_ARDUINO_SDK_BUILD_DIR))

  $(call check_build_dir, $(SDK_TOOLCHAIN_DIR))
endif

export MKENV_INCLUDED = 1
export MPP_FOR_CANMV_SDK = 1

MK_IMAGE_NAME?=$(call qstrip,$(CONFIG_BOARD_NAME))
export MK_IMAGE_NAME
export SDK_TOOLCHAIN_DIR?=$(shell echo $$HOME)/.kendryte/k230_toolchains
export SDK_TOOLS_DIR=$(SDK_SRC_ROOT_DIR)/tools
# Default target
.DEFAULT_GOAL := all

It exports SDK_TOOLCHAIN_DIR as the toolchain path /home/fs/.kendryte/k230_toolchains. $ is used to declare variables, and $$HOME is the content of a variable.
It exports SDK_TOOLS_DIR as /home/fs/workspace/K230/rtos/tools
.DEFAULT_GOAL := all means that if you run make with no arguments, it runs make all

  • qstrip: qstrip = $(strip $(subst ",,$(1))) Purpose: strip quotes and then whitespace. Because the underlying config file .config often contains quoted variables (e.g. CONFIG_BOARD="k230_evb"), and quotes would cause errors when used for path assembly in a Makefile, this function exists specifically to peel "k230_evb" down to k230_evb.
  • check_build_dir: uses the shell to check whether a directory exists; if not, it mkdir -ps it into existence.
  • del_mark: searches the whole project for the .parse_config cache file and deletes it (usually for clearing out old configuration).
  • sync_dir: calls the powerful rsync command to sync the source directory to the destination directory, ensuring incremental copying.
  • gen_kconfig: aggregates each module's own Kconfig into the overall build directory for use by the graphical configuration interface.
MAKEFLAGS += --no-print-directory
...
ifeq ($(BUILD_VERBOSE),0)
Q = @
else
Q =
endif
RM = rm -rf
ECHO = echo
CP = cp
MKDIR = mkdir
SED = sed
CAT = cat
TOUCH = touch
PYTHON = python3
ZIP = zip
INSTALL = install
  • Anti spam: it turns off Make's default "Entering directory xxx" / "Leaving directory xxx" flood of messages.
  • The V=1 mechanism: this is a very classic design from the Linux kernel build. By default Q = @, and prefixing a Makefile command with @ hides the actual command being executed (for example, hiding an extremely long gcc -c ...), printing only a short message. But if you're troubleshooting a build error, you type make V=1 in the terminal, Q becomes empty, and all the real compilation commands being executed underneath are exposed.
  • The file then defines aliases for common commands such as RM, CP, MKDIR in one place, for cross-platform compatibility.**
# Check if 'bear' command exists
BEAR_EXISTS := $(shell command -v bear >/dev/null 2>&1 && echo yes || echo no)

BEAR_COMMAND ?= bear

ifeq ($(BEAR_EXISTS),yes)
  # Capture the Bear version
  BEAR_VERSION := $(shell bear --version | grep -oE '[0-9]+\.[0-9]+\.[0-9]+')

  # Convert BEAR_VERSION to a single integer and compare it to 30000
  BEAR_VERSION_INT := $(shell echo $(BEAR_VERSION) | awk -F. '{print ($$1*10000 + $$2*100 + $$3)}')

  # Check if the Bear version is 3.0.0 or greater
  ifneq ($(shell [ $(BEAR_VERSION_INT) -ge 30000 ] && echo true),)
      BEAR_COMMAND := bear --
  endif
endif

export BEAR_COMMAND
PARALLEL ?= $(shell if command -v nproc > /dev/null 2>&1; then nproc; \
            elif [ -f /proc/cpuinfo ]; then grep -c '^processor' /proc/cpuinfo; \
            elif command -v sysctl > /dev/null 2>&1; then sysctl -n hw.ncpu; \
            else echo 1; fi)

export NCPUS?=$(PARALLEL)

CONFIG_SDK_ENABLE_CANMV ?= n
  • The Bear interceptor: bear is an extremely powerful tool that intercepts all compilation arguments while make is building and generates compile_commands.json. That file is the foundation for precise C/C++ code navigation and smart completion in modern IDEs like VSCode and CLion. This code thoughtfully checks whether bear is installed in your environment, and whether the version is the latest 3.0+.
  • PARALLEL: automatically sniffs out your computer's CPU core count (using nproc or sysctl) and assigns it to NCPUS, preparing for later parallel builds (such as make -j8).
def_config :=$(filter %_defconfig,$(MAKECMDGOALS))

ifneq ($(def_config),)
  ifeq ($(shell if [ -f $(SDK_SRC_ROOT_DIR)/configs/$(def_config) ]; then echo 1; else echo 0; fi;), 0)
    $(error "Please specify a valid CONFIG")
  endif

  CONFIG_BOARD_CONFIG_NAME := $(def_config)
else
  -include $(SDK_SRC_ROOT_DIR)/.config
endif

CONFIG_BOARD := $(call qstrip,$(CONFIG_BOARD))

export CONFIG_SDK_ENABLE_CANMV

ifeq ($(strip $(filter $(MAKECMDGOALS),list_def list-def dl_toolchain)),)
  ifeq ($(CONFIG_BOARD_CONFIG_NAME),)
    $(error "Please run make xxx_defconfig first. Use 'make list-def' to see available configurations.")
  endif
endif

MK_LIST_DEFCONFIG?=$(CONFIG_BOARD_CONFIG_NAME)
export MK_LIST_DEFCONFIG
  • MAKECMDGOALS: a built-in Make variable representing the command goals you typed into the terminal.
  • Logic branches:
    1. If you typed make k230_evb_defconfig in the terminal, it checks whether that config file actually exists under the configs/ directory. If it does, it stores the name in CONFIG_BOARD_CONFIG_NAME.
    2. If you just typed make, it quietly does include $(SDK_SRC_ROOT_DIR)/.config to read in the previous configuration.
  • Interceptor: if there is no configuration (for example, you just downloaded the code), and the command you're running isn't one of the list (list_def) or download-toolchain (dl_toolchain) commands, the system errors out and stops you right there ($(error "Please run make xxx_defconfig first...")), forcing you to pick a board.
    $(filter %_defconfig, ...)
  • This is Make's string filtering function.
  • Syntax: $(filter <pattern>, <text>)
  • Purpose: selects from <text> the words that match the <pattern>.
  • % is the wildcard, matching any sequence of any length.
  • %_defconfig means: match strings ending in _defconfig.
    The code after that handles def_config — it checks whether that config file exists and then runs the relevant logic: what to do if it exists, and what to do if it doesn't.
    MK_LIST_DEFCONFIG?=$(CONFIG_BOARD_CONFIG_NAME) sets a default value.
export UBOOT_DEFCONFIG=$(patsubst %,%_defconfig,$(call qstrip,$(CONFIG_UBOOT_CONFIG_FILE)))
export RTSMART_DEFCONFIG=$(patsubst %,%_defconfig,$(call qstrip,$(CONFIG_RTSMART_CONFIG_FILE)))

export SDK_BOARDS_DIR=$(SDK_SRC_ROOT_DIR)/boards
export SDK_BOARD_DIR=$(SDK_BOARDS_DIR)/$(call qstrip,$(CONFIG_BOARD))

export SDK_OPENSBI_SRC_DIR=$(SDK_SRC_ROOT_DIR)/src/opensbi
export SDK_RTSMART_SRC_DIR=$(SDK_SRC_ROOT_DIR)/src/rtsmart
export SDK_UBOOT_SRC_DIR=$(SDK_SRC_ROOT_DIR)/src/uboot
export SDK_CANMV_SRC_DIR=$(SDK_SRC_ROOT_DIR)/src/canmv
export SDK_APPS_SRC_DIR=$(SDK_SRC_ROOT_DIR)/src/applications

export SDK_BUILD_DIR=$(SDK_SRC_ROOT_DIR)/output/$(call qstrip,$(CONFIG_BOARD_CONFIG_NAME))

export SDK_OPENSBI_BUILD_DIR=$(SDK_BUILD_DIR)/opensbi
export SDK_RTSMART_BUILD_DIR=$(SDK_BUILD_DIR)/rtsmart
export SDK_UBOOT_BUILD_DIR=$(SDK_BUILD_DIR)/uboot
export SDK_CANMV_BUILD_DIR=$(SDK_BUILD_DIR)/canmv
export SDK_APPS_BUILD_DIR=$(SDK_BUILD_DIR)/applications

export SDK_ARDUINO_SDK_BUILD_DIR=$(SDK_SRC_ROOT_DIR)/output/arduino-sdk

export SDK_BUILD_IMAGES_DIR=$(SDK_BUILD_DIR)/images

ifeq ($(strip $(filter $(MAKECMDGOALS),list_def list-def dl_toolchain)),)
  $(call check_build_dir, $(SDK_BUILD_IMAGES_DIR))

  $(call check_build_dir, $(SDK_OPENSBI_BUILD_DIR))
  $(call check_build_dir, $(SDK_RTSMART_BUILD_DIR))
  $(call check_build_dir, $(SDK_UBOOT_BUILD_DIR))
  $(call check_build_dir, $(SDK_CANMV_BUILD_DIR))
  $(call check_build_dir, $(SDK_APPS_BUILD_DIR))
  $(call check_build_dir, $(SDK_ARDUINO_SDK_BUILD_DIR))

  $(call check_build_dir, $(SDK_TOOLCHAIN_DIR))
endif

export MKENV_INCLUDED = 1
export MPP_FOR_CANMV_SDK = 1

MK_IMAGE_NAME?=$(call qstrip,$(CONFIG_BOARD_NAME))
export MK_IMAGE_NAME
  • The source area (src/): it pins down the source locations of OpenSBI (low-level firmware), U-Boot (bootloader), RT-Smart (real-time system), CanMV (AI vision framework), and Applications (application layer).
  • The output area (output/): all compiled .o files and images are absolutely not allowed to pollute the source directory; they must all be output under output/<your board name>/. This also makes it convenient to do a thorough cleanup with make distclean — just delete the output folder and everything is gone.

Changelog

9/25/26, 12:44 PM
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