How to use the Yocto Project to develop Embedded Linux

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How to use the Yocto Project to develop Embedded Linux

The Yocto Project™ is an open source collaboration project that provides templates, tools and methods to help you create custom Linux-based systems for embedded products regardless of the hardware architecture. Taken directly from the Yocto Project website:

Yocto Project™ it's not an embedded Linux distribution – it creates a custom one for you

The Yocto Project™ is an umbrella project covering a fairly wide swath of embedded Linux technologies an distributions. For example, the Angstrom Distribution is declared as a Yocto Project Participant

Much of this How-To is extracted from different sources. If you would like to read some of the original articles or resources, please visit them and thank the authors:

Overview of How-To

This How-To is meant to be a starting point for people to learn build and run Yocto-based images for IGEP Technology devices as quickly and easily as possible.

Why use the Yocto Project™

Because it's a complete embedded Linux development environment with tools, metadata, and documentation - everything you need. The free tools are easy to get started with, powerful to work with (including emulation environments, debuggers, an Application Toolkit Generator, etc.) and they allow projects to be carried forward over time without causing you to lose optimizations and investments made during the project’s prototype phase. The Yocto Project fosters community adoption of this open source technology allowing its users to focus on their specific product features and development

Build Platform Setup Environment

In order to build an image with BSP support for a given release, you need to download the corresponding BSP repository. At this time latest stable branch for IGEP devices is denzil.

 $ git clone -b denzil git://git.isee.biz/pub/scm/poky.git

Enter to the poky directory,

 $ cd poky

and clone the meta-isee layer.

 $ git clone -b denzil git://git.isee.biz/pub/scm/meta-isee.git
 $ source oe-init-build-env

Having done that, and assuming you downloaded the BSP contents at the top-level of your yocto build tree, you can build a igep image by adding the location of the 'meta-igep' layer to 'bblayers.conf'

Add below line into .../poky/build/conf/bblayers.conf:

       <path to>/poky/meta-isee \

To enable the isee layer, add the 'igep00x0 MACHINE' to .../poky/build/conf/local.conf:

 MACHINE ?= "igep00x0"

You should then be able to build a image as such:

 $ bitbake demo-image-sato

At the end of a successful build, you should have an image that you could use for boot device from flash or a micro-SD card.

Extending the available packages with others layers

You can append more layers to your environment in order to build more packages, in following wxample you'll download the meta-openembedded layer. In your poky directory

 $ git clone -b denzil git://git.openembedded.org/meta-openembedded

Add the layer into build/conf/bblayers.conf:

       <path to>/poky/meta-openembedded/meta-oe \

Now you can build any of the new packages added, for example:

 $ bitbake postgresql

Create your own Linux image

TODO

Yocto 1.2 'denzil' documentation

Official documentation

Notes

Ubuntu 13.04

WARNING: Host distribution "Ubuntu 13.04" has not been validated with this version of the build system; you may possibly experience unexpected failures. It is recommended that you use a tested distribution.

Although denzil branch is not validated for "Ubuntu 13.04" we have successfully build denzil images with this distribution, see notes below:

Note 1: If you get the following error, or similar:

NOTE: package prelink-native-1.0+git1+7b47f2f8a15ed13b7905bc120bb2586f3e164f7d-r9: task do_fetch: Started
WARNING: Failed to fetch URL git://git.yoctoproject.org/prelink-cross.git;protocol=git
ERROR: Fetcher failure: Fetch command export HOME="..."; export SSH_AGENT_PID="2230"; export SSH_AUTH_SOCK="..."; export GIT_CONFIG="..."; git remote add --mirror=fetch origin git://git.yoctoproject.org/prelink-cross.git could not be run:

Remove the local build of git-native

bitbake git-native -c cleanall

and assume as provided adding the following line to conf/local.conf

ASSUME_PROVIDED += "git-native"

Note 2: If you get the following error, or similar:

INSTALL net/netfilter/xt_policy.ko
|   MKDIR   .../tmp/work/igep00x0-poky-linux-gnueabi/linux-igep-2.6.37-r6/image/lib/firmware/edgeport/
| make[1]: *** No rule to make target `.../image/lib/firmware/./', needed by `.../whiteheat_loader.fw'.  Stop.
| make[1]: *** Waiting for unfinished jobs....
| make: *** [_modinst_post] Error 2
| ERROR: oe_runmake failed
NOTE: package linux-igep-2.6.37-r6: task do_install: Failed

Remove the local build of make-native

bitbake make-native -c cleanall

and assume as provided adding the following line to conf/local.conf

ASSUME_PROVIDED += "make-native"

See also

External links

Others IGEP wiki articles