Status of Embedded Linux

1. Status of Embedded Linux CE Worgroup Work Update May 2011 Tim Bird Architecture Group Chair LF CE Workgroup

2. Outline • Status of merger with Linux Foundation • CELF contract work • Review of 2010 work • Plan for 2011 work • Conferences • Other meetings • Other initiatives

3. Merger Status

4. Merger with Linux Foundation • Merger was completed in January 2011 • Some final legal details still being wrapped up • CELF is now the Linux Foundation “CE Workgroup” • Now starting to utilize Linux Foundation infrastructure • Should mean it's easier for non-members to participate in CE WG projects!

5. Contract Work 2010

6. CELF Contract Work 2010 • Bootchart and smemcap in busybox • Function-sections • YAFFS2 mainline effort • SquashFS enhancements • U-Boot ARM enhancements • Trace format standard • Kexecboot enhancements • Flash filesystem testing

7. Bootchart and smemcap support in busybox Smemcap applet • Bootchart applet - Captures bootchart data • See http://elinux.org/Japan_Technical_Jamboree_33 • See http://elinux.org/Bootchart#BusyBox • Smemcap applet – captures smem data • Data can be moved to host for analysis and visualization • Contractor: Denys Vlasenko • Status: Completed • Applets are available in busybox mainline

8. Function-sections • Description: • Add support to Linux kernel for gcc –ffunction-sections option, to shrink kernel size by improving dead code removal • Puts each function in its own linker section • Required a big section rename in kernel • Contractor: Denys Vlasenko • Status: • Most parts mainlined • Waiting to resolve linker issues for weird symbols on PARISC • Effort stalled – need to finish it

9. Mainline YAFFS2 • Description: • YAFFS2 is a popular NAND flash filesystem • Was used by Android in many devices • Add support for YAFFS2 to mainline kernel • Contractor: Aleph One Ltd • Google Co-Sponsored this project • Status: • 3 mainline attempts made, but hit some barriers • Currently stuck on some locking issues • Outlook for mainline acceptance is uncertain

10. SquashFS LZMA/LZO Support • Description: • LZMA and LZO support • Contractor: Phillip Lougher • Status: • LZMA work was submitted, and was in Linux-next, but got rejected • LZO work (contributed by LGE) was mainlined!!

11. ARM improvements in U-boot • Description: • Improve aspects of U-boot for ARM • Allow relocating bootloader • Turn caches on for faster booting • Contractor: Wolfgang Denx • Status: • Work was completed and mainlined in U-Boot

12. U-Boot Results: • Limit for boot time into app code is 5s so U-boot image compression was not possible. But now it is. • Results from Matthias Weißer on Aug 5, 2010 • Seehttp://article.gmane.org/gmane.comp.boot-loaders.u-boot/82079

13. Trace format standard • Description: • Create a singled trace format standard for the embedded industry • Contractor: Efficios (Matthieu Desnoyers) • Status: • Standard (Common Trace Format) was created • See http://www.efficios.com/ctf • BabelTrace trace conversion library • Proof of concept conversion implementation • Can convert kernel messages with timestamps to CTF and back to text

14. Kexecboot improvements • Description: • Improve user interface and supported storage devices for kexecboot • Contractor: Yuri Bushmelev • Status: • Interface has been enhanced • Work on reading other storage devices was completed

15. Flash filesystem testing • Description: • Measure different flash filesystems for comparisons • Contractor: Free Electrons • Status: • Results were shown at ELC Europe 2010

16. Contract Work 2011

17. Open Project Proposal • Project ideas were collected in Dec. 2010 and Jan. 2011 • Bids were solicited in March • Architecture Group approved projects in April • 11 projects approved out of 28 • Still have budget for more projects • Contracts are being finalized now • Have a good list, but would like more proposals from CE WG/LF members

18. Contract Work 2011 • Improve UBIFS mount time • Mainline Android kernel features • Mainline fast symbol resolution • Work on Linux tiny patches • Support read-only block filesystems on flash devices

19. Contract Work 2011 (cont.) • eLinux wiki content for kernel trace and debug • Mainline the watchdog framework • Flash filesystem testing • Extend bluetooth stack with Remote SIM Access protocol • Mainline Device Firmware Upgrade (DFU) code in U-Boot • Solicit project proposals throughout year

20. Improve UBIFS mount time • Description: • Add logging or checkpointing to UBI to avoid bad-block scan of whole device on UBI attach • Contractor: Linutronix (Thomas Gleixner) • Status: • Contract almost finished

21. Mainline Android kernel features • Description: • Add a single Android feature (logger) to mainline, as a pilot project for 3rd party mainlining of Android code • Longterm goal is to mainline as much of Android as possible, to reduce difference and allow for easier “unified distro kernel” • Kernel that can run Ubuntu, Android, etc. • Contractor: have interest from Alessio Bogani • Status: • Still working on project plan and bid

22. Mainline fast symbol resolution • Description: • Change symbol lookup to use binary search instead of linear scan • Speeds up module loading • Contractor: Alessio Bogani • Status: • Patches are in linux-next

23. Work on Linux tiny patches • Description: • Revive Linux-tiny patch set • Forward-port patches to latest kernel • Add more patches to improve kernel configurability • Contractor: We Zhanjin • Status: • Contract ready to sign

24. Support read-only block filesystems on flash media • Description: • Write block emulation layer to support read-only filesystems on top of MTD layer in kernel • Will allow Squashfs to be used on raw NAND flash media • Contractor: Phillip Lougher • Status: • Contract in progress

25. eLinux wiki content for trace and debug • Description: • Collect content on kernel trace and debug techniques and publish on eLinux wiki • Contractor: Peter Huewe • Status: • Contract ready to sign

26. Mainline the watchdog framework • Description: • Mainline the watchdog framework • Original framework was written by Alan Cox and others • Provides a generalized watchdog mechanism • Should provide easier method to add watchdogging to drivers and the kernel going forward • Contractors: Wolfram Sang and Wim van Sebroeck • Status: • Contract ready to sign

27. Flash filesystem testing • Description: • Perform mount and runtime performance tests on multiple flash filesystems, for each new kernel release • Publish results on eLinux wiki • Contractor: Free Electrons • Status: • Contract ready to sign

28. Extend bluetooth stack with Remote SIM Access protocol • Description: • Allows for Linux bluetooth and telephony stack to utilize SIM in external device for operation • Primary use case is for Linux-based in-car system to utilize SIM in mobile device for calls, etc. • Contractor: ProFusion • Status: • Contract almost complete

29. Mainline Device Firmware Upgrade (DFU) code in U-Boot • Description: • Device Firmware Upgrade (DFU) is an industry standard system for upgrading and manipulating firmware in embedded devices • Add support for this protocol to U-Boot mainline • Contractor: Stefan Schmidt • Status: • Contract ready to sign

30. Solicit project proposals throughout the year • Description: • CE Workgroup will continue to maintain the Project Proposal wiki page, and will continue accepting ideas and proposals for contract work through 2011 • This will allow ideas to come in as they are generated and relevant, instead of accumulating them throughout the year • Contractor: Bill Traynor • Status: • Contract ready to sign

31. Conferences

32. Conferences • Past • ELC 2011 and Android Builders Summit • Videos just announced – see wiki page • Kato-san will give a report later today • Future • LinuxCon Japan – June 1-3, Yokohama • ELC Europe 2011 – Oct 26-28, Prague • LinuxCon Brazil – Nov 17-18, Sao Paulo • Continuing Japan Jamborees • ELC and Android Builders Summit in 2012 • See http://events.linuxfoundation.com/ and http://elinux.org/events

33. Embedded Linux Summit • Invitation-only event to discuss embedded issues between key industry and community leaders • Was held September 30, 2010 in Tokyo and October 26 in Cambrige, UK • Similar to other mini-summits, but with focus on embedded issues • Leading up to kernel summit in November • Has lead to several initiatives • Big one was longterm kernel branch, maintained by Andi Kleen

34. Android mainline BOF • Invitation-only event to discuss Android mainline issues • Was held April 14 in San Francisco • Linaro, CE WG, Google and Qualcomm attended • Very good discussion about what different members of the “Android/Linux ecosystem” could do to coordinate work and mainline Android technologies • CE WG “mainline Android logger” project is a result of this meeting

35. Other Initiatives

36. eLinux Wiki • http://elinux.org/ • Wikipedia for embedded Linux developers • Very good for some technical areas • I have been working on Android Portal section of site • Recently moved to OSU Open Source Lab hosting • Promotion • Contest – just finished best editor contest! • Please use it and post stuff

37. Hardware Donations • CELF donates hardware for some open source developers • example: Board for BKL removal work • E-mail me if you need hardware for a project that you think CELF would be interested in

38. Thanks!