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Yocto Project Linux as a platform for embedded system design
The document discusses the Yocto Project as a platform for developing embedded systems, highlighting its benefits over binary distributions. It outlines the key considerations for embedded operating systems, such as power consumption, security, and real-time capabilities, as well as differentiating between various development roles. It concludes with a comparison of Buildroot and Yocto for different project scales and complexities.
Yocto Project Linux as a platform for embedded system design
- 1. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.1 YOCTO PROJECT LINUX AS A PLATFORM FOR EMBEDDED SYSTEM DESIGN OR, WHAT IS THE BEST OPEN SOURCE OS CHOICE FOR MY EMBEDDED SYSTEM? ALEX.GONZALEZ@DIGI.COM
- 2. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.2 WHY THIS PRESENTATION? • Digi manufactures System-On-Modules (SOMSs) and Single Board Computers (SBCs) • Provides free reference software (BSP and Yocto Project based distribution) • Why use a Yocto Project based distribution?
- 3. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC. Common embedded OS considerations: • Power consumption • User interface, possibly graphical • Quick start up time • Security • Networking • Some amount of RT determinism 3 WHAT IS AN EMBEDDED SYSTEM? Cost and time to market are directly proportional to the complexity
- 4. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC. Common embedded OS considerations: • Power consumption • User interface, possibly graphical • Quick start up time • Security • Networking • Some amount of RT determinism 4 REAL TIME CONSIDERATIONS Cost and time to market are directly proportional to the complexity
- 5. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.5 MICROCONTROLLER OR MICROPROCESSOR MCU CPU • Flat memory model • Extensive use of JTAG debuggers • Open source operating systems • FreeRTOS, mbed, Zephyr • Hard real time • Virtual memory (MMU) • Limited use of JTAG debuggers • Open source operating systems • Embedded Linux • Real time considerations • Soft RT (PREEMPT_RT) • Hard RT not really Linux • RTLinux, RTAI, Xenomai
- 6. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.6 EMBEDDED LINUX DEVELOPMENT CONSIDERATIONS
- 7. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.7 EMBEDDED LINUX DISTRIBUTION An embedded Linux distribution provides: • The bootloader • The Linux kernel • The root filesystem • A software development kit Sets system policies: • Selection of supported packages • Initialization system • Graphical backend and environment • System wide choices
- 8. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.8 EMBEDDED LINUX DEVELOPMENT • Bigger development teams • Different development roles • BSP developers • System developers • Application developers • SDK used as an interface
- 9. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.9 BSP DEVELOPMENT • Bootloader development • Similar to traditional embedded development • Bring-up • Intimate with hardware • Flat memory model • JTAG debuggers • Linux kernel development • Similar to PC kernel developers • JTAG of little use • BSP/drivers provided by OEM and community • Mostly device tree customization and driver debugging and development
- 10. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.10 APPLICATION DEVELOPMENT • Abstracted by Linux kernel • Similar to PC desktop application development • QT • Web applications • C and C++ • Also Python, Node.js and Java • The application is a collection of services that collaborate and communicate
- 11. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.11 SYSTEM DEVELOPMENT • System integration • Build system • Root filesystem generation • SDK generation • Toolchain • Sysroot
- 12. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.12 EMBEDDED LINUX DISTRIBUTIONS BINARY OR BUILD FROM SOURCE
- 13. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.13 EMBEDDED LINUX DISTRIBUTIONS • A customized existing binary Linux distribution • For example Debian • A distribution built from source • Do it yourself • For example using crosstool-ng and Cross LFS • Standard tools • Buildroot • Yocto Project
- 14. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.14 BINARY LINUX DISTRIBUTIONS • Pre-built packages installed and removed using a package manager • On-target compilation common • Package maintenance by the distribution provider • Limited package configuration • Generic, heavily patched packages • Not focused on embedded applications needs • Bigger systems • Slower to boot • Require more resources to run • More difficult to secure
- 15. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.15 BINARY LINUX DISTRIBUTIONS • Pre-defined policies and architectural choices • Customization needed for most embedded systems lead to manual non-standard builds • Difficult to reproduce • High maintenance cost • Package manager updates unsuited for embedded • Can´t guarantee deployed system is the same as tested system • Power loses while updating leave the system in inconsistent states
- 16. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.16 EMBEDDED LINUX DISTRIBUTIONS BINARY OR BUILD FROM SOURCE BINARY SOURCE • Lowest complexity and time to market for supported hardware • High maintainability • Bigger images • Slower to boot • More resources to run • More difficult to secure • Low reproducibility • Low portability and scalability • Longer development cycles • Full configuration possibilities • Maximum flexibility, no pre- determined choices • Easier maintenance as long as needed • Smaller images • Faster to boot • Lower resources to run • Easier to secure • High portability and scalability
- 17. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.17 EMBEDDED LINUX DISTRIBUTIONS BUILDROOT OR YOCTO PROJECT
- 18. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.18 BUILD FROM SOURCE LINUX DISTRIBUTIONS BUILDROOT • Easy to use • Ideal for small projects and teams • Uses kbuild as configuration tool • All configuration in one place • Good selection of well-maintained packages • External packages can be added • Three months release cadence • Yearly LTS release • More image generator than distribution builder • Does not generate binary packages • Does not support package managers • Only performs full system updates • Does not support on target compilation • Full system rebuilds often required • No concept of build cache
- 19. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.19 BUILD FROM SOURCE LINUX DISTRIBUTIONS YOCTO PROJECT • Distribution builder • Poky reference distribution • Openembedded build system • Bitbake scheduler • Build binary packages that are installed into root filesystem images • Package managers on target for development • Large number of packages structured in layers • Software re-use • Distributed maintenance • Six month release cadence • Current and previous releases are maintained • Configuration in several places • Distro, machine, image and local • Scales to multiple platforms and bigger teams • Steeper learning curve
- 20. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC. • No one-size-fits-all embedded operating system • For CPUs, embedded Linux covers most use cases • RT considerations apply • Build from source distributions better suited than binary distributions • Small projects and teams are a good fit for Buildroot • The Yocto Project scales better to bigger projects, teams and multiple platforms 20 SUMMARY
- 21. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC.21 EMBEDDED LINUX DEVELOPMENT USING YOCTO PROJECT COOKBOOK DISCOUNT CODES Discount codes valid until 26th March 2018. • Ebook 50% discount: ELDUYPC50 • Paperback copy 15% discount: ELDUYPC15 • Limited availability! Some free copies available at Digi´s booth • Hall 3 booth 518
- 22. DIGI.COM | PUBLIC| © DIGI INTERNATIONAL, INC. Questions? 22 Thanks for listening. Alex González, Software Supervisor, Digi International Alex.Gonzalez@digi.com