Getting started with Yocto on Wandboard
Requirements hardware and software
- Linux-based host system to use for building Linux
- Wandboard Dual (currently only Wandboard Dual is supported but Solo will be added soon)
- Null-modem serial (RS-232) cable use for the serial console
- 5V power supply to power the Wandboard
- microSD card to store the bootloader, kernel, and filesystem as Wandboard has no on-board flash
Steps for a first-time build
Here are the steps to building an image for Wandboard with Yocto for the first time:
- Download and install Google's repo utility
- Create the main BSP install directory and, using repo, download all of the metadata for the BSP layers.
- Build an image using bitbake
- Locate the built image and write it to SD card
Download and install Google's repo utility
The BSP is based on the Yocto Project, which consists of a number of applicable metadata 'layers'. These are managed by the repo utility.
$: mkdir ~/bin
$: curl https://dl-ssl.google.com/dl/googlesource/git-repo/repo > ~/bin/repo
$: chmod a+x ~/bin/repo
Create the BSP directory download all of the metadata for the BSP layers
$: mkdir fsl-community-bsp
$: cd fsl-community-bsp
$: repo init -u https://github.com/Freescale/fsl-community-bsp-platform -b master
$: repo sync
Once this has completed, you should have all of the metadata source in fsl-community-bsp.
Setup environment and build an image
To start a build, first set a shell environment variable to set the machine to "wandboard-dual".
setup-environment script. This is a helper script which sets up the environment and creates a build directory for you.
$: . ./setup-environment build
Run bitbake with
core-image-minimal as its argument. This will create a small image and should have the shortest possible build time. Note: all of the sources are downloaded from the internet and built from scratch. This includes the toolchain (gcc) and all of the native utilities, so building an image for the first time could take a few hours, depending on the performance of your host machine.
$: bitbake core-image-minimal
Locating the images and installing to a microSD card
Once the image is built successfully, there are several target images that are built by default. One of these is an image suitable for loading directly into an SD card. It contains all of the required binaries (bootloader, kernel, filesystem) in a preformatted binary image.
You can find the image at:
That image can be directly copied to an SD card with the
sudo dd if=tmp/deploy/images/core-image-minimal-wandboard-dual.sdcard of=/dev/sd<N> bs=1M
NOTE: "N" in the above command is the letter assigned to the SD card. This will vary depending on your host machine configuration.