Build system (BELK/BXELK)

Introduction

A build system is a set of tools, source trees, Makefiles, patches, configuration files and scripts that makes it easy to generate all the components of a complete embedded Linux system. A build system, once properly set up, automates the configuration and cross-compilation processes, generating all the required targets (userspace packages such as libraries and programs, the kernel, the bootloader and root filesystem images) depending on the configuration. In particular, using an integrated build system prevents from problems caused by misaligned toolchains, since a unique toolchain is used to build all the software components, including the customer application. Some well known structured build systems are the following:

• OpenEmbedded (http://wiki.openembedded.net/index.php/Main_Page)
• Yocto (https://www.yoctoproject.org/)
• Buildroot (http://buildroot.uclibc.org).

Since various heterogeneous tools are required to build the software components for the BORA/BORAX SOM, BELK does not provide a fully structured build system. In particular, the Xilinx Zynq 7000 development tools are required to configure the system and build the FSBL, while the standard GNU tools are required to build U-Boot, kernel and user-space applications. In the following section, we will refer to the system running the Xilinx tools (that can be either a Microsoft Windows machine or a GNU/Linux machine) as the “Zynq development server”, and to the machine running the GNU/Linux tools as the “Linux development server”.

Setting up the Zynq development server environment

The following software packages must be installed on the Zynq development server:

• Vivado® Design Suite version 2014.4
• Xilinx Software Development kit
• Python 2.7.x (C:\Python27 must be the installation directory on Windows)
• A Git tool (e.g. for Windows: MsysGit http://msysgit.github.io/).

The Zynq 7000 development tools can be downloaded from the Xilinx website: http://www.xilinx.com/support/download/index.htm in the WebPACK™ Edition, which is a free version that provides instant access to the fundamental Vivado features and functionality at no cost. For the hardware requirements of the PC, please refer to http://www.xilinx.com/design-tools/vivado/memory.htm#zynq-7000. The Git tool is used to download the BORA/BORAX project files for Vivado from DAVE Embedded Systems' public git repositories, as described in the next section.

N.B. Sometimes the download of the Vivado 2014.4 full package fails because of some download system malfunctioning, but the problem is barely noticeable, except by performing the MD5 check of the downloaded file. In case of problems, we suggest using the Multi-File Download (available on the same web page), that splits the full package in a collection of smaller files. If you use the Multi-File Download to get the "Vivado (No SDK)" package, you must also download the "Software Development Kit - 2014.4" package.