Adding a toolchain
Introduction [edit section]
In order to build tests for your target board, you need to install a toolchain (often in the form of an SDK) into the fuego system, and let fuego know how to access it.Adding a toolchain to Fuego consists of these steps:
- 1. obtain (generate or retrieve) the toolchain
- 2. copy the toolchain to the container
- 3. install the toolchain inside the container
- 4. create a -tools.sh file for the toolchain
- 5. reference the toolchain in the appropriate board file
Obtain a toolchain [edit section]
First, you need to obtain a toolchain that will work with your board.If you are using an ARM-based target, then to get started, you may use the pre-installed armv7hf toolchain. However, there is no guarantee that this will work on your board. It is much better to install your own SDK for your board into the fuego system.
Building a Yocto Project SDK [edit section]
When you build an image in the Yocto Project, you can also build an SDK to go with that image using the '-c do_populate_sdk' build step with bitbake.To build the SDK in Yocto Project, inside your yocto build directory do:
- bitbake <image-name> -c do_populate_sdk
This will build an SDK archive (containing the toolchain, header files and libraries needed for creating software on your target, and put it into the directory <build-root>/tmp/deploy/sdk/
For example, if you are building the 'core-image-minimal' image, you would execute:
$ bitbake core-image-minimal -c do_populate_sdk
Install the SDK in the docker container [edit section]
To allow fuego to use the SDK, you need to install it into the fuego docker container. First, transfer the SDK into the container using docker cp.With the container running, on the host machine do:
- docker ps (note the container id)
- docker cp tmp/deploy/sdk/<sdk-install-package> <container-id>:/tmp
This last command will place the SDK install package into the /tmp directory in the container.
Now, install the SDK into the container, into /userdata/toolchains.
At the shell inside the container, run the SDK install script (which is a self-extracting archive):
- /tmp/poky-....sh
- during the installation, specify an installation path under /userdata/toolchains, like: /userdata/toolchains/poky/2.0.1
These instructions are for an SDK built by the Yocto Project. Similar instructions would apply for installing a different toolchain or SDK. That is, get the SDK into the container, then install it into /userdata/toolchains. Note that it is not strictly required that the SDK be installed there - it can be installed anywhere you need to (say, under /opt), but the convention is to place toolchains under userdata for consistency, and to make them visible to both the container and the host.
Create a -tools.sh file for the toolchain [edit section]
Now, fuego needs to be told how to interact with the toolchain. During test execution, the fuego system determines what toolchain to use based on the value of the PLATFORM variable in the board file for the target under test. The PLATFORM variable is a string that is used to select the appropriate 'tools.sh' file in /userdata/toolchains.You need to determine a name for this PLATFORM, and then create a file with that name, called $PLATFORM-tools.sh. So, for example if you created an SDK with poky for the qemuarm image, you might call the PLATFORM "poky-qemuarm". You would create a file called "poky-qemuarm-tools.sh"
The -tools.sh file is used by Fuego to define the environment variables needed to interact with the SDK. This includes things like CC, AR, and LD. The complete list of variables that this script neeeds to provide are described on the page tools.sh
Inside the -tools.sh file, you execute instructions that will set the environment variables needed to build software with that SDK. For an SDK built by the Yocto Project, this involves setting a few variables, and calling the environment-setup... script that comes with the SDK. For SDKs from other sources, you can define the needed variables by directly exporting them.
Here is an example of the tools.sh script for poky-qemuarm. This is in the sample file /userdata/toolchains/poky-qemuarm-tools.sh:
# fuego toolchain script
# this sets up the environment needed for fuego to use a toolchain
# this includes the following variables:
# CC, CXX, CPP, CXXCPP, CONFIGURE_FLAGS, AS, LD, ARCH
# CROSS_COMPILE, PREFIX, HOST, SDKROOT
# CFLAGS and LDFLAGS are optional
#
# this script is sourced by /userdata/conf/tools.sh
POKY_SDK_ROOT=/userdata/toolchains/poky/2.0.1
export SDKROOT=${POKY_SDK_ROOT}/sysroots/armv5e-poky-linux-gnueabi
# the Yocto project environment setup script changes PATH so that python uses
# libs from sysroot, which is not what we want, so save the original path
# and use it later
ORIG_PATH=$PATH
PREFIX=arm-poky-linux-gnueabi
source ${POKY_SDK_ROOT}/environment-setup-armv5e-poky-linux-gnueabi
HOST=arm-poky-linux-gnueabi
# don't use PYTHONHOME from environment setup script
unset PYTHONHOME
env -u PYTHONHOME
Reference the platform in a board file [edit section]
Now, to use that SDK for building test software for a particular target board, set the value of the PLATFORM variable in the board file for that target.Edit the board file:
- vi /userdata/conf/boards/foo.board
And add (or edit) the line:
- PLATFORM="poky-qemuarm"
Notes [edit section]
Python execution [edit section]
You may notice that some of the example scripts set the environment variable ORIG_PATH. This is used by the function run_python internally to execute the container's default python interpreter, instead of the interpreter that was built by the Yocto Project.
Previous versions of Fuego/JTA [edit section]
In previous versions of Fuego and JTA (before September, 2016), you added support for a platform by editing the file /userdata/conf/tools.sh. This method of adding support for a new toolchain is deprecated, in favor of the current system of adding a separate file for each toolchain installed in the system.