Rapid Embedded Prototyping with Open Source: Software and Hardware Alison Chaiken Nokia Mobility Solutions Sunnyvale CA firstname.lastname@example.org July 12, 2011Principles: Reuse components, both own and COTS, HW and SW Modular, flexible design Unit testing at regular preplanned intervals
Open Source Platform Features to Consider● Compatible CPU architectures● Vendor support, documentation and maintenance and license● Ported applications, “app store”● Toolchain (compiler, debugger, package manager)● Software development kit and integrated dev. environment● Real-time performance
MeyerSounds D-MitriEmDebian runs real-time audio for Cirque du Soleil, Disney.
Embedded Linux or alternative? Soft real-Have MMU? GPLv2 OK? time OK? Want Linux Driver Power use features? availability? OK? Tools, Existing supportLinux port? OK?
MeeGo Linaro Android ÅngstromOrganization Foundation Non-profit Consortium CommunityMembership None Core, Club, Unclear None CommunityPlanning/gov Open on IRC + Board, TSGs in Private Come again?er-nance private privateprocessLicense LGPL Upstreams Apache v2 UpstreamsCorporate 16∓: Intel, TI, ARM, “over 80,” esp. Noneparticipants Nokia?, AMD, Freescale, IBM, Mentor in Fujitsu, Samsung, ST embedded Renesas Ericsson, TISupported Atom (x86), ARMv7: Cortex ARMv7, ARMv5, ARM, PowerPC,architectures ARMv7, MIPS in A8, A9, & A15 PowerPC, x86, MIPS, SuperH, progress MIPS AVRShipping WeTab, Not yet legion Gumstixproducts IndaMixx, Amino, Geely, HawTai
Cross-Platform Apps on Mobile POSIX Plus, port of iOS apps to MeeGo led by Intels S. Crabtree with LLVM developers in Argentina!Myriads Alien DalvÍk on Maemo RIMs AndroidPlayer on QNX Debians Iced Robot
Qt Runs EverywhereDeeply embedded (“bare metal”) or headless all the way to desktop.
MeeGo “Special Sauce”● Qt application framework and GUI toolkit● Connman connection manager● Simplified Mandatory Access Control Kernel (Smack)● Intended to be reconfigured and reskinned: an “upstream”● Easier to port mainline Linux components to MeeGo than to Android
Surprisingly strong developer supportReflects big efforts by Intel and MeeGo vendor community.
MeeGo Problems● Security and synchronization systems left dangling due to project changes● Lack of continuity and predictability ● GTK → Qt ● Debian package manager to RedHat one ● Nokia exit ● Netbook and handset now unsupported, TV and tablet added● 5th place (?) in handset/tablet space ● Do “deeply embedded” OEMs care?
HW Development Platform Requirements● Versatility: support for different buses, comms and display protocols● Expandability: ports, headers and daughter cards● Software platform support● Documentation: manuals, gerbers● Device drivers!
Notable ARM Dev Boards in use by aMeeGos TI BeagleBoard XM x1 Cortex A8 with SGX530 GPU TI Pandaboard x2 Cortex A9 with SGX540 GPU ST-Ericsson Snowball x2 Cortex A9 with Mali GPU
Other Prototyping possibilities Gumstix Overo x1 Cortex A8 with SGX530 GPUIntel N450 Mini-ITXx1 Atom, “integrated graphics” Variscite AM35 Freescale iMX53 QuickStart x1 Cortex A8 600 MHz, CAN bus x1 Cortex A8 1 GHz, SATA
Gentils Demo at ELC2011http://elinux.org/images/5/5c/ELC-AlwaysInnovating-Gentil.pdf
Lessons from the Trenches● chroot approach demonstrated by Gentil is fast, powerful and widely applicable● Pick popular HW platform for accessories, docs and tools● Device driver situation is painful no matter what selection is made
Summary● Wide selection, decent tools and good docs enable rapid prototyping using open source.● Embedded Linux is useful in many cases.● Where “app store” is irrelevant, MeeGo is easier than Android.● Starting with ARM or Atom reference board saves a lot of headaches.● Linaro and Yocto projects are promising.● Proprietary device drivers are the biggest problem on any platform.
Linux Security for Embedded Environments● Sandboxing and cgroups● Hardware approach like DRM → GPU decoding● SELinux versus Smack● Java approach: ● dont prevent impermissible actions in policy; instead intentionally omit the facility for implementation of them● Nothing like “airgap” security at the end of the day
MeeGo-IVI On OMAP4 Pandaboard withHW- accelerated Graphics
Yocto Project Eases Custom Linux Builds● Based on Open Embedded, with better UI and more quality control● Source for board-support packages and device drivers,even proprietary and binary ones, where available● Complete toolchain including revision control, compilation,packaging and testing● Support for many architectures and software variants● Broad industrial support
Linaro: improving Linux on ARM● Industry contributions for ARM to Linux kernel are a mess● Tools lag x86● Broad industrial support can enable code reuse and encourage best practices● Primarily funded by Canonical and IBM● Still early in development