Intel® Edison - adding kernel modules to Yocto - example "Batman"

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Recently I was asked how to add batman-adv to Yocto. I put together my answer email and it turned out slightly lengthy - looked like it should go into a blog ;-)

Option 1 - kindly ask others to do the work

Check availability in existing repos like http://repo.opkg.net/edison/. In our concrete example we can find the prerequesite libnl in http://repo.opkg.net/edison/repo/core2-32/ but no b.a.t.m.a.n* [by now it has been added to the repo - still keeping this blog]. Hence we could kindly ask e.g. AlexT on https://communities.intel.com/thread/55692?start=0&tstart=0 whether he could add the packages "kernel-module-batman-adv" as well as "batctl" to http://repo.opkg.net/edison/. If you are lucky he might do but it's voluntary work on his side.

The packages can be installed via "opkg install <package name>"

Option 2 - compile on target

Slightly more difficult - and requires sufficient free space on Intel(R) Edison rootfs. Install kernel sources on the target and compile modules on the target

Option 3 - build in Yocto build environment

requirements

• Linux x64 host system (e.g. Ubuntu* 12.04 [have heard about issues running Yocto* on 14.04 - maybe resolved by now], Fedora* 20, ...)
• min 50 GB free disk space (at least if you want to compile the whole Yocto image)

Yocto setup

• download "Yocto complete image" from http://www.intel.com/support/edison/sb/CS-035180.htm
• tar xvf edison-src*.tgz
• cd edison-src
• device-software/setup.sh
• source poky/oe-init-build-env

build kernel-modules-batman-adv

• bitbake -c menuconfig virtual/kernel; this will open a new window running Linux kernel config for Edison
• configure batman: within the menuconfig session configure the b.a.t.m.a.n* options you want to see within the Networking Support > Networking Options > BATMAN category
• cp build/tmp/work/edison-poky-linux/linux-yocto/<your current kernel>/linux-edison-standard-build/.config device-software/meta-edison/recipes-kernel/linux/files/defconfig
• bitbake -c compile_kernelmodules virtual/kernel
• in case you require the complete modules tarball: bitbake -c deploy virtual/kernel – you'd find the tarball under build/tmp/deploy/images/edison geschrieben
• otherwise: opkg install build/tmp/deploy/ipk/edison/kernel-module-batman-adv_<version>.ipk on your target

The configs I changed:

< # CONFIG_BATMAN_ADV is not set
---
> CONFIG_BATMAN_ADV=m
> CONFIG_BATMAN_ADV_BLA=y
> CONFIG_BATMAN_ADV_DAT=y
> CONFIG_BATMAN_ADV_NC=y
> # CONFIG_BATMAN_ADV_DEBUG is not set

batctl

In order to make use of batman you should also install batctl. On the web you can find bitbake recipes. I used and adopted https://github.com/openembedded/openembedded/blob/master/recipes/batctl/batctl.inc as per below:

mkdir -p device-software/meta-edison-distro/recipes-support/batman/

cat > device-software/meta-edison-distro/recipes-support/batman/batctl_2014.4.0.bb <<EOF

DESCRIPTION = "Control application for B.A.T.M.A.N. routing protocol kernel module for multi-hop ad-hoc mesh networks."
HOMEPAGE = "http://www.open-mesh.net/"
SECTION = "console/network"
PRIORITY = "optional"

LICENSE = "GPLv2+"
LIC_FILES_CHKSUM = "file://../license-destdir/${PN}/generic_GPLv2;md5=801f80980d171dd6425610833a22dbe6"

RDEPENDS_${PN} = "kernel-module-batman-adv"
DEPENDS = "libnl"


SRC_URI = "http://downloads.open-mesh.net/batman/stable/sources/batctl/batctl-${PV}.tar.gz\
     file://patch.patch"
SRC_URI[md5sum] = "f3a14565699313258ee6ba3de783eb0a"
SRC_URI[sha256sum] = "77509ed70232ebc0b73e2fa9471ae13b12d6547d167dda0a82f7a7fad7252c36"

EXTRA_OEMAKE = 'STAGING_INC="${STAGING_INC}"'

do_compile() {
  oe_runmake
}

do_install() {
  install -d ${D}${bindir}
  install -m 0755 batctl ${D}${bindir}
}
EOF

As libnl has changed its include installation path I had to patch the Makefile of batctl. The patch as per below:

mkdir -p device-software/meta-edison-distro/recipes-support/batman/files
cat > device-software/meta-edison-distro/recipes-support/batman/files/patch.patch <<EOF

--- a/Makefile  2015-02-27 09:10:45.768409932 +0100
+++ b/Makefile  2015-02-27 09:11:32.710554513 +0100
@@ -29,7 +29,7 @@
MANPAGE = man/batctl.8

 # batctl flags and options
-CFLAGS += -Wall -W -std=gnu99 -fno-strict-aliasing -MD -MP
+CFLAGS += -Wall -W -std=gnu99 -fno-strict-aliasing -MD -MP –I${STAGING_INC}/libnl3
CPPFLAGS += -D_GNU_SOURCE
LDLIBS += -lm
EOF

After that one can bitbake batctl with:

bitbake batctl

After completion you'll find the package in build/tmp/deploy/ipk/core2-32/batctl_2014.4.0-r0_core2-32.ipk. It can be directly installed via "opkg install" on Intel(R) Edison running Yocto* Linux

Test on Intel(R) Edison after installation

root@edison:~/ # modprobe batman-adv

If you want to have the module auto-loaded you'd probably want to enter it in /etc/modules-load.d/

root@edison:~/ # modinfo batman-adv
filename:       /lib/modules/3.10.17-poky-edison+/kernel/net/batman-adv/batman-adv.ko
version:        2013.2.0
description:    B.A.T.M.A.N. advanced
author:         Marek Lindner <lindner_marek@yahoo.de>, Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
license:        GPL
srcversion:     66711903985B5CAAE0DAF30
depends:       
intree:         Y
vermagic:       3.10.17-poky-edison+ SMP preempt mod_unload ATOM

Using a USB eth dongle:

root@edison:~/ # batctl if add enp0s17u1
root@edison:~/ # batctl if
enp0s17u1: active
root@edison:~/ # batctl s
     tx: 6
     tx_bytes: 468
     tx_dropped: 0
     rx: 1
     rx_bytes: 42
     forward: 0
     forward_bytes: 0
     mgmt_tx: 60
     mgmt_tx_bytes: 2428
     mgmt_rx: 0
     mgmt_rx_bytes: 0
     tt_request_tx: 0
     tt_request_rx: 0
     tt_response_tx: 0
     tt_response_rx: 0
     tt_roam_adv_tx: 0
     tt_roam_adv_rx: 0
     dat_get_tx: 0
     dat_get_rx: 0
     dat_put_tx: 0
     dat_put_rx: 0
     dat_cached_reply_tx: 0
     nc_code: 0
     nc_code_bytes: 0
     nc_recode: 0
     nc_recode_bytes: 0
     nc_buffer: 0
     nc_decode: 0
     nc_decode_bytes: 0
     nc_decode_failed: 0
     nc_sniffed: 0

# ifconfig bat0
bat0      Link encap:Ethernet  HWaddr 52:78:97:51:ba:9d  
          inet6 addr: fe80::5078:97ff:fe51:ba9d/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST DYNAMIC  MTU:1500  Metric:1
          RX packets:1 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:42 (42.0 B)  TX bytes:468 (468.0 B)