This project shows Yocto meta layer for integrating Wifi USB driver of Realtek RTL8188EUS (highly integrated single-chip 802.11n WLAN network USB interface controller) into Linux Image of phyBoard Mira.
In case of Wifi USB stick, I have tested it with TL-WN725N 150Mbit/s-WLAN-Nano-USB-Adapter as on the following link: https://www.tp-link.com/de/home-networking/adapter/tl-wn725n/
In case of embedded board, I have used phyBoard Mira for testing, but it should work for other embedded boards with USB port without big changes. Link with description of phyBoard Mira is here: https://www.phytec.de/produkte/single-board-computer/phyboard-mira-imx6/
Here I will show instructions that would work in case of phyBoard Mira board, and what might change for others.
Hardware prerequisites for integrating this Yocto meta layer:
-
Embedded board similar to phyBoard Mira
-
WiFi USB stick which uses RTL8188EU chip, like for example TL-WN725N
-
Something which can bring generated zImage, oftree, barebox and rootfs to your embedded board.
I used USB-C to Gigabit LAN-adapter from ISY, but microSD Card should work as well
-
USB to Serial Adapter Cable for serial communication with embedded board
Software prerequisites for integrating this Yocto meta layer:
-
Virtual machine for development with phyBoard Mira as from this link: https://download.phytec.de/Products/i.MX6/SO-547v5_PD22.1.0/Virtual_Machine/
It contains everything we need for quick start
First we create a folder for the BSP.
Enter the following commands:
sudo mkdir ‐p /opt/PHYTEC_BSPs/phyBOARD‐MIRA/
sudo chmod ‐R 777 /opt/PHYTEC_BSPs/
cd /opt/PHYTEC_BSPs/phyBOARD‐MIRA/
Download the phyLinux script and set execution privileges:
wget ftp://ftp.phytec.de/pub/Software/Linux/Yocto/Tools/phyLinux
chmod +x ./phyLinux
The phyLinux script is a basic management tool for PHYTEC Yocto BSP releases. It is mainly a tool to get started with the BSP structure. You can get all the BSP sources without the need of interacting with repo or git.
Start the phyLinux script:
./phyLinux init
During the execution of the init command, you need to choose your processor platform (iMX6), PHYTEC's BSP release number (PD20.1.0) and the hardware you are working on (in my case phyboard-mira-imx6-3).
After you downloaded all the meta data with phyLinux, you have to set up the shell environment variables. This needs to be done every time you open a new shell for starting builds. We use the shell script provided by poky in its default configuration.
Type:
source sources/poky/oe‐init‐build‐env build_minimal_stick
The current working directory of the shell should change to build_minimal_stick/ and you are now ready to build your first images.
Go to conf/ directory and add new file sanity.conf in this directory with following contents:
# Sanity checks for common user misconfigurations
#
# See sanity.bbclass
#
# Expert users can confirm their sanity with "touch conf/sanity.conf"
BB_MIN_VERSION = "1.42.0"
SANITY_ABIFILE = "${TMPDIR}/abi_version"
POKY_CONF_VERSION = "1"
LAYER_CONF_VERSION = "1"
SITE_CONF_VERSION = "1"
INHERIT += "sanity"
Now open file local.conf in this conf/ directory. Add these contents near the beginning of this file (by changing existing lines or uncommenting them):
DL_DIR = "${TOPDIR}/../../downloads"
SSTATE_DIR = "${TOPDIR}/../../sstate-cache"
TMP_DIR = "{TOPDIR}/tmp"
Change files related to license handling:
LICENSE_FLAGS_WHITELIST += "license-freescale_v12-march-2016_firmware-imx"
ACCEPT_FSL_EULA = "1"
Change these lines in local.conf file (I added nano just for ease of usage on embedded board later):
IMAGE_INSTALL_append = " nano tree kernel-module-r8188eu \
linux-firmware-rtl8188 \
dhcp-client \
iw \
wpa-supplicant \
wireless-regdb-static \
"
IMAGE_INSTALL_remove += " packagegroup-userland "
# Autoload WiFi driver on boot
KERNEL_MODULE_AUTOLOAD += "r8188eu"
Add this line at the end of local.conf file to save some space on hard-disk:
INHERIT += "rm_work"
Now open file bblayers.conf in this conf directory. You will need to add this meta layer in this file. In my case, bblayers.conf looked like this at the end:
BBPATH = "${TOPDIR}"
BBFILES ?= ""
OEROOT := "/opt/PHYTEC_BSPs/phyBOARD-MIRA/sources/poky"
BBLAYERS ?= " \
${OEROOT}/meta \
${OEROOT}/meta-poky \
${OEROOT}/../meta-openembedded/meta-oe \
${OEROOT}/../meta-openembedded/meta-networking \
${OEROOT}/../meta-openembedded/meta-python \
${OEROOT}/../meta-openembedded/meta-multimedia \
${OEROOT}/../meta-openembedded/meta-filesystems \
${OEROOT}/../meta-openembedded/meta-perl \
"
BBLAYERS += "\
${OEROOT}/../meta-phytec \
${OEROOT}/../meta-qt5 \
${OEROOT}/../meta-rauc \
${OEROOT}/../meta-security \
${OEROOT}/../meta-virtualization \
${OEROOT}/../meta-yogurt \
${OEROOT}/../meta-rtl8188eu \
"
Leave generated build_minimal_stick folder. If you list directories of your current folder with ls, it would look like this:
phytec-dev-ca sources HOWTO
python tools build_minimal_stick
phyLinux ReleaseNotes
Now go to directory sources and clone this github repository:
git clone [email protected]:RijadSK/meta-rtl8188eu.git
Well, I have hard-coded settings of my WLAN in meta-rtl8188eu/recipes-bsp/drivers/files/wpa_supplicant-wlan0.conf. Those WLAN settings would not be helpful to you.
You would either like to change these settings or to manually type in these commands after your embedded board boots:
wpa_passphrase “<SSID>” “<WiFi Password>” >> /etc/wpa_supplicant/wpa_supplicant-wlano.conf
wpa_supplicant -B -i wlan0 -D wext -c /etc/wpa_supplicant/wpa_supplicant-wlan0.conf
In order to enable Linux kernel driver for RTL8188EU chip, we have to change Linux kernel settings as well.
In recipes-kernel/linux/files/defconfig are settings which we are applying during generating of Linux image:
Networking support > Networking options (following should be enabled):
[*] TCP/IP networking
[*] IP: kernel level autoconfiguration
[*] IP: DHCP support
[*] IP: BOOTP support
[*] IP: RARP support
<*> The IPv6 protocol
Networking support > Wireless
<M> cfg80211 - wireless configuration API
[*] cfg80211 wireless extensions compatibility
<M> Generic IEEE 802.11 Networking Stack (mac80211)
[*] Minstrel (for rate control in 802.11)
Device Drivers> Network device support > Wireless LAN
[*] Realtek devices
< > Realtek rtlwifi family of devices
< > Realtek RTL8192CU/RTL8188CU USB Wireless Network Adapter
[ ] Debugging output for rtlwifi driver family
< > RTL8723AU/RTL8188[CR]U/RTL8192[12]CU (mac80211) support
[ ] Include support for untested Realtek 8xxx USB devices (EXPERIMENTAL)
Device Drivers > USB support, make sure USB Host is enabled:
<*> Support for Host-side USB
[*] Enable USB persist by default
Device Drivers > Staging Drivers
<M> Realtek RTL8188EU Wireless LAN NIC driver
[ ] Realtek RTL8188EU AP mode (NEW)
[*] Enable loadable module support --->
[*] Module signature verification
[*] Require modules to be validly signed
[*] Automatically sign all modules
Which hash algorithm should modules be signed with? (SHA-256)
If you are not using phyBoard Mira board, then you would need to change file recipes-kernel/linux/linux-mainline_%.bbappend so that these settings apply to your Linux image.
You can also generate these kernel settings from defconfig file yourself with command bitbake -c menuconfig virtual/kernel.
Go back to our generated build_minimal_stick directory and type:
bitbake phytec-headless-bundle
All build artifacts will be generated in build_minimal_stick/deploy/ directory.
At the end, you should find oftree, zImage and phytec-headless-image-phyboard-mira-imx6-3.ubifs in your generated deploy/ directory. I have used TFTP-Server Tftpd64 on Windows for downloading generated artifacts to embedded board (see https://pjo2.github.io/tftpd64/). I have used PuTTY for serial communication with my board.
Plug in your Wifi USB stick into board.
After booting of your board, you can connect to your WLAN as follows:
wpa_passphrase “<SSID>” “<WiFi Password>” >> /etc/wpa_supplicant/wpa_supplicant-wlano.conf
wpa_supplicant -B -i wlan0 -D wext -c /etc/wpa_supplicant/wpa_supplicant-wlan0.conf
I have hard-coded my WLAN settings in this layer, so it happens automatically for me.
You can check if you have connected to WLAN by typing ifconfig
You can try to download contents of example website to check if everything is working as expected:
wget -qO - http://example.com
Distributed under the MIT License. See LICENSE.txt for more information.