MANAGING A REAL-TIME EMBEDDED LINUX PLATFORM WITH BUILDROOT John Diamond, Kevin Martin Fermi National Accelerator Laboratory, Batavia, IL 60510
Desktop distributions are an awkward Buildroot + ucLibc + Busybox + RTAI Quantitative Results implementation of an Embedded RTOS Buildroot – downloads, unpacks, • Whole build process is automated resulting in • Architecture-dependent binary configures, compiles and installs system much quicker build times (hours not days) software automatically • Kernel and root filesystem size: 3.5 MB – 20 packages uClibc – Small-footprint standard C library MB (reduction of 99%) • Loaded with unnecessary software Busybox – all-in-one UNIX utilities and shell • Boot-time: ~9 seconds • Huge footprints RTAI – Real-Time Linux extensions
= Qualitative Results • Allows integration with revision control into First Try: Build Linux from Source the platform development process, making it • Success! But.. 2. Buildroot’s menuconfig generates a package configuration file easier to manage an ecosystem of targets • Is as difficult as it sounds and kernel configuration file • Community support for x86 & ARM targets Linux Kernel • Overwhelming number of packages and Configuration gives us confidence that future targets can be patches Package supported without much effort 1. Developer Configuration • No version control configures build via Buildroot’s • Cross-compile even more headaches menuconfig
Internet Build Process Power Supply Control Quench Protection Git / CVS / SVN and Regulation for the System for Tevatron Did not do what we needed: Fermilab Linac Electron Lens (TEL II) 3. The build process pulls 4. The output from the software packages from build process is a kernel • Small-footprint network bootable image the internet and custom bzImage bzImage file with an softare packages from a integrated root filesystem ARM Cortex A-9 source code repository file PC/104 AMD • Automated build system Geode SBC Beam Position Monitor Power Supply Control prototype for Fermilab and Regulation for • Support for multiple architectures 5. The target’s bootloader Booster NuMI beam line downloads the bzImage NFS • Integrated system for building and file at boot time from a Share network filesystem Intel Core 2 Duo PC/104 Integrated Target deploying real-time application software VME/VXS in NIM module