Introduction Me: Software Engineer at DENX, Gmbh U-Boot Custodian - - PowerPoint PPT Presentation

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Introduction Me: Software Engineer at DENX, Gmbh U-Boot Custodian - - PowerPoint PPT Presentation

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Software Update on Embedded Systems Do not brick your device Stefano Babic ELCE October 2014 Introduction Me: Software Engineer at DENX, Gmbh U-Boot Custodian for Freescale's i.MX Focus on Linux embedded with PowerPC and ARM

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Software Update on Embedded Systems Do not brick your device

Stefano Babic ELCE October 2014

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Introduction

  • Me:

– Software Engineer at DENX, Gmbh – U-Boot Custodian for Freescale's i.MX – Focus on Linux embedded with PowerPC and ARM

processors.

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Agenda

  • Why upgrade ?
  • Why is it different with a Linux-PC ?
  • Upgrading strategies
  • Swupdate
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Why do we need to update an embedded system ?

  • It is not only hardware
  • Bug fixes
  • New features can be added
  • Security issues : heartbleed, bad implementation...
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Why is ES different ?

  • Power failure
  • Bad firmware
  • Communication errors in

case of remote update

  • No access to target

Target must recover from errors !

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Which elements must be updated ?

  • Bootloader (dangerous !)
  • Kernel + DT
  • Root filesystem
  • Application data, other filesystems..
  • Customer data (migration )
  • Specific software (FPGA bitstream,...)
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Where is a new SW installed ?

NOR NAND

FPGA

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Which interface ?

  • Local:

– Local storage (USB, SD,..) – Local peripheral (USB as device, UART,..)

  • Remote:

– HTTP / web based – FTP – Proprietary protocol – Many more...

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Who will update ?

X X

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No expertise required

+

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System upgrade solutions

  • Bootloader upgrade
  • Linux upgrade

– Package Manager – Rescue image or specific application – From the running application

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Bootloader

Limited access to peripherals (drivers, filesystems) Implementation in bootloader not in sync with Linux Limited network support (UDP, not TCP) Limited UI with an operator Update is simpler Smaller footprint

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Linux App

Footprint Availability of all drivers used by the product A lot of tools/libraries

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package manager as distro ?

Upgrade is not atomic Nightmare for test engineers/support New firmware partially written More places where things can go wrong Small update image

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Full update

Size, Time to transfer Atomic: it works or not Single image delivery

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Double copy strategy

BOOT LOADER Application Software Running copy Application Software Standby copy Databases, config, user data BOOT LOADER Application Software Standby copy Application Software Running copy Databases, config, user data
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Single copy (rescue)

BOOT LOADER SWUPDATE Kernel + initrd Application Software Databases, config, user data
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swupdate: FLOSS upgrade sw

  • Missing an open source upgrade software for ES
  • Take care of failure mechanism
  • Hardware / software compatibility
  • Proof correctness images to be installed (chksum,..)
  • Partitioning storage
  • Local or remote install
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Swupdate-2

  • Scriptable (LUA), pre- and postinstall scripts
  • Single image for multiple devices
  • Easy for users to perform update
  • Missing : signed images !
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Handling hardware differences

MENU ALARMS OVERVIEW Q UANTITY Brandon-Alvin ViewerPane K600

HMI Gateway Type A-1 Type A-2 Type A-3 Type A-4

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One release, multiple devices

Type A-1

MENU ALARMS OVERVIEW QUA NTITY Brandon-Alvin ViewerPane K600

HMI Software for A-1 Software for A-3 Software for HMI Release XX.YY for device family Type A-3

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Single image structure

CPIO Header sw-description Image 1 Image 2 Image 3 Image i Image n
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Swupdate architecture

Local Storage WebServer Custom protocol INSTALLER Default Parser (libconfig) Custom Parser (LUA) UBI MTD RAW U-Boot ENV Custom LUA Handler API Handler manager Notifier

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Handling HW differences

software = { version = "0.1.0"; target-1 target-1 = { images: ( { ... } ); }; target-2 = { images: ( { ... } ); }; }

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sw-description

software = { version = "0.1.0"; myboard = { hardware-compatibility: [ "1.2", "1.3", "18#010071"]; partitions: ( /* UBI Volumes */ { name = "rootfs"; device = "mtd10"; size = 104896512; /* in bytes */ }, { name = "kernel"; device = "mtd9"; size = 4194304; /* in bytes */ } );

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sw-description

images: ( { filename = "core-image-base-myboard.ubifs"; volume = "rootfs"; }, { filename = "uboot-env"; type = "uboot"; }, { filename = "uImage"; volume = "kernel"; }, { filename = "fpga.bin"; type = "fpga"; } );

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sw-description: scripts, u-boot

scripts: ( { filename = "test.lua"; type = "lua"; }, { filename = "sdcard.lua"; type = "lua"; }, { filename = "test_shell.sh"; type = "shellscript"; } ); uboot: ( { name = "vram"; value = "4M"; }

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Recovery from failures

U-Boot Swupdate Set update flag Update flag set ? Reset update flag run success Load kernel fail Kernel boots Application Reset bootcounter Bootcounter ? Panic, watchdog,..

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API for external client

Client swupdate

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Updating from browser

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Using with Yocto

  • Meta-swupdate
  • It generates a ramdisk suitable for u-boot (.uboot.gz)
  • “dora” and “daisy” branches
  • Footprint RAMDISK (gzipped) : 2.6 – 7 MB

– Typical: ~4MB

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Handler in LUA

require ("swupdate") fpga_handler = function(image) print("Install FPGA Software ") for k,l in pairs(image) do print("image[" .. tostring(k) .. "] = " .. tostring(l) ) swupdate.notify(swupdate.RECOVERY_STATUS.RUN,0, "image[" .. tostring(k) .. "] = " .. tostring(l)) end return 0 end swupdate.register_handler("fpga",fpga_handler)

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swupdate todo list

  • Create a community around the project
  • Security: add support for signed images !
  • Low resources: support for full streamable image
  • New handlers
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Links

  • Swupdate sources at

https://github.com/sbabic/swupdate

  • Documentation at http://sbabic.github.io/swupdate
  • Mailing list: swupdate@googlegroups.com
  • http://www.denx.de/
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Questions ...

  • It's your turn now...