OpenWRT guide and memo

OpenWRT

Basic tutorial guide, memo.by Antony.Wu

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OpenWRT builtroot• It is a set of Makefiles and patches that allows users to generate

a cross-toolchain and a root filesystem for embeded system.• It generates cross-compiler toolchain and use the toolchain to

build an image for your target board, such as AR-5387un router.• It can also download packages (feeds), patches (using quilt) it

for you.• # make toolchain/gdb/prepare QUILT=1• <modify files in build_dir/>• # make toolchain/gdb/updatevim

• It has modified make targets: component/name/action.• # make toolchain/gdb/compile V=s

• V=s means “Verboase = stdout/stderror”• # make toolchain/gdb/clean V=s

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V=?

s standard output/error

w shows only warning

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Get OpenWRT buildroot

Main repositories and feeds # git clone git://git.openwrt.org/openwrt.git # git clone git://git.openwrt.org/packages.git

Barrier Breaker # git clone git://git.openwrt.org/14.07/openwrt.git # git clone git://git.openwrt.org/14.07/packages.git # svn co -r 42990

svn://svn.openwrt.org/openwrt/branches/barrier_breaker

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Setup OpenWRT environmentUsing Fedora distribution, you need the following

package ready. # yum install -y subversion binutils bzip2 gcc gcc-c++ gawk

gettext flex ncurses-devel zlib-devel make patch unzip perl-ExtUtils-MakeMaker glibc glibc-devel glibc-static quilt ncurses-lib sed sdcc intltool sharutils bison wget

Check environment variables # echo $SED # must be empty, or issue '# unset SED' # echo $GREP_OPTIONS # don't contain '--initial-tab'

Set the PATH: PATH=$PATH:<buildroot dir>/staging_dir/host/bin PATH=$PATH:<buildroot dir>/staging_dir/toolchain-

<platform>-<gcc_ver>-<libc_ver>/bin

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Understand OpenWRT FeedsIt is a set of packages, like a ‘yum repo’, or ‘apt-get repo’ on

desktop linux. The script downloads the packages info into ‘feeds/’ . The script installs packages into ‘package/feeds/’ Packages in feeds selectable by CONFIG_PACKAGE_xxxx in .config

file.

The repo is configured in the feeds.conf or feeds.conf.default (such as yum repo configured in /etc/yum.repos.d)

A script is used to control those packages # ./scripts/feeds update -a

Package index (information) will be stored into feeds/ # ./scripts/feeds install <package_name>

Src will be checkouted into package/feeds/<package_name>

OpenWRT Make

• Clean• # make clean # rm -rf bin build_dir

• # make dirclean # rm -rf bin build_dir staging_dir toolchain logs

• # make distclean # all above, rm all downloaded packages and .config

• Ignore errors• #IGNORE_ERRORS=1 make <make options>

• component/name/action.• Clean Linux objects

• # make target/linux/clean V=s

• Clean package luci.• # make package/luci/clean

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OpenWRT Make sequence

1. # make tools/install

2. # make toolchain/install

3. # make target/compile

4. # make package/cleanup

5. # make package/compile

6. # make package/install

7. # make package/preconfig

8. # make target/install

9. # make package/index

You can issue them, one by one, in order, so that you can check and debug each step.

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Create OpenWRT package• Special Makefile template.

• Please refer to BuildPackage variablesPKG_NAME:=broadcom-wlPKG_VERSION:=5.10.56.27.3PKG_RELEASE:=5

PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION)_$(ARCH).tar.bz2PKG_SOURCE_URL:=http://downloads.openwrt.org/sources ……$(eval $(call KernelPackage,brcm-wl))$(eval $(call KernelPackage,brcm-wl-mini))$(eval $(call BuildPackage,wlc))$(eval $(call BuildPackage,wl))$(eval $(call BuildPackage,nas))

• BuildPackage only takes one argument directly – the name of the package to be built, in this case “wlc".

# ls -l package/broadcom-wl/files # default config.Makefilepatches # patches from diffsrc # source code

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Create OpenWRT package 2• BuildPackage define ‘Package/’

• The following describe the ‘define’ you may need:define Package/broadcom-wl/Default

<action>endef

• Package/description : description

• Package/conffiles : config-files installed by this pkg.

• Build/Prepare (optional): How to unpack/patch src.

• Build/Configure (optional) : How to configure src.

• Build/Compile (optional) : How to compile src.

• Build/InstallDev (optoinal) : Lib. needed

• Please refer to BuildPackage defines

Note: ‘define’ in makefile is like ‘=‘ operator.

Define the action when calling ‘Package/broadcom/wl/Default ‘

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Create OpenWRT package 3• Override Build option

• Autoconf• Eg. CONFIGURE_VARS += ac_cv_header_regex_h=no• Eg. CONFIGURE_ARGS += --disable-native-affinity

• Compiler flags• Eg. TARGET_CFLAGS+= -Wall

• Make• Eg. MAKE_VARS = CFLAGS="$(TARGET_CFLAGS) $(EXTRA_CFLAGS)

$(TARGET_CPPFLAGS) $(EXTRA_CPPFLAGS)" \ …• Eg. MAKE_FLAGS = $(TARGET_CONFIGURE_OPTS) \ CROSS="$

(TARGET_CROSS)" ARCH="$(ARCH)“• CMake and Scons

• CMAKE_OPTIONS, CMAKE_HOST_OPTIONS• SCONS_VARS

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Create OpenWRT package 4• Adding configuration options

• Add MENU:=1• Add Config.in Package/<name>/configMakefile:

define Package/mjpg-streamer/config source "$(SOURCE)/Config.in“ endef

Config.in:menu "Configuration" depends on PACKAGE_mjpg-streamer config MJPEG_STREAMER_AUTOSTART bool "Autostart enabled" default n

• How to check your configurationMakefile:

ifeq ($(CONFIG_MJPEG_STREAMER_INPUT_UVC),y) $(CP) $(PKG_BUILD_DIR)/input_uvc.so $(1)/usr/lib endif

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Create OpenWRT package 5• Working on local application source

• Using feeds to tracking your state-of-the-art work.# ln -s /path/to/local/awesome_app_tree/.git feeds/my_cool_feed/awesome_app/git-src # make package/awesome_app/{clean,compile} V=s

• Using USE_SOURCE_DIR# make package/awesome_app/clean V=s # make package/awesome_app/prepare USE_SOURCE_DIR=~/src/awesome_src V=s # make package/awesome_app/clean V=s

• make prepare needs to be run every time• make package/awesome_app/{clean,compile}

USE_SOURCE_DIR=~blah doesn't work

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OpenWRT kernel package Adding configuration options

Add .mk file#vim package/kernel/modules/block.mk

define KernelPackage/loop SUBMENU:=$(BLOCK_MENU) TITLE:=Loopback device support KCONFIG:= CONFIG_BLK_DEV_LOOP CONFIG_BLK_DEV_CRYPTOLOOP=n

FLES:=$(LINUX_DIR)/drivers/block/loop.ko AUTOLOAD:=$(call AutoLoad,30,loop)endef$(eval $(call KernelPackage,loop))

Announce to build system.# touch package/kernel/linux/Makefile

Add a kernel module that is not part of kernel distribution Please refer to ‘package/madwifi/Makefile’

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What’s in the following slides?

1. # make tools/install

2. # make toolchain/install

3. # make target/compile

4. # make package/cleanup

5. # make package/compile

6. # make package/install

7. # make package/preconfig

8. # make target/install

9. # make package/index

You can issue them, one by one, in order, so that you can check and debug each step.

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External Toolchain Compile everything with the target board,

you will have a dir named toolchain, called build1

Copy the .config-file from the build1 and make menuconfig.

[*] Advanced configuration options (for developers)[*] Use external toolchainTarget name: arm-openwrt-linux-uclibcgnueabi (in my case, yours may vary)Toolchain prefix: arm-openwrt-linux-uclibcgnueabi- (mind the dash at the end)Toolchain root: /path/to/toolchain/staging_dir/toolchain-arm_v5te_gcc-linaro_uClibc-0.9.32_eabi

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Alter download procedure $DL_DIR is the location for download

Through "include/download.mk“ Init in “rules.mk”

To share downloaded packages Put them in a shared location /opt/… Check them in download procedure “define Download”

in file “download.mk” MEMO: we can use shell to do this.

Eg . test -e /opt/dl/$(FILE) && ln -s /opt/dl/$(FILE) $(DL_DIR)/$(FILE) || ( $(if $(DownloadMethod/$(call dl_method,$(URL),$(PROTO))),$(DownloadMethod/$(call dl_method,$(URL),$(PROTO))),$(DownloadMethod/unknown)) )

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What has been added?dl/ # for downloaded src.build_dir/ # source code location

├── host ├── target-mips_mips32_uClibc-0.9.33.2 └── toolchain-mips_mips32_gcc-4.8.3_uClibc-0.9.33.2

logs/ # for compile logs ├── target ├── toolchain └── tools

staging_dir/ # built out binary files. ├── host ├── target-mips_mips32_uClibc-0.9.33.2 └── toolchain-mips_mips32_gcc-4.8.3_uClibc-0.9.33.2

tmp/

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What’s in the following slides?

1. # make tools/install

2. # make toolchain/install

3. # make target/compile

4. # make package/cleanup

5. # make package/compile

6. # make package/install

7. # make package/preconfig

8. # make target/install

9. # make package/index

You can issue them, one by one, in order, so that you can check and debug each step.

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Add our own BSP in target The makefile in target will go into each

subdir. Create a dir <BSP> of yours in the target dir. Create a Makefile contains the following target.

all, download, prepare,

compile, install, clean

This also apply to the general ruls Eg # make target/<BSP>/prepare

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Reference

1. http://wiki.openwrt.org/doc/start2. http://wiki.openwrt.org/about/toolchain3. http://wiki.openwrt.org/doc/devel/packages

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