Beagle Board 101

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Title: Beagle Board 101

1
Beagle Board 101

Gerald Coley and Jason Kridner
September 22, 2009
Archived athttp//beagleboard.org/esc

2
Agenda

Overview of the Beagle Board
Board features and community
Booting the Beagle Board
Some simple tests (learning Linux)
Writing our own boot script
Native, managed, and web-based UI code
development
Collaboration tools and community participation
Resources for more information and support
Hardware presentation
Lessons from building Beagle

3
Whats in a name

Bring your own peripherals
Entry-level cost (149)
ARM Cortex-A8 (superscalar)
Graphics and DSP accelerated
Linux and open source community
Environment for innovators

4
Community development
Wikis, blogs, promotion of community activity
gt 2,000 participants and growing
Addressing open source communityneeds
Instant access to gt10 million lines of code
Open access to hardware documentation
5
Fast, low power, flexible expansion

OMAP3530 Processor
600MHz Cortex-A8
NEONVFPv3
16KB/16KB L1
256KB L2
430MHz C64x DSP
32K/32K L1
48K L1D
32K L2
PowerVR SGX GPU
64K on-chip RAM
POP Memory
128MB LPDDR RAM
256MB NAND flash

Peripheral I/O
DVI-D video out
SD/MMC
S-Video out
USB 2.0 HS OTG
I2C, I2S, SPI,MMC/SD
JTAG
Stereo in/out
Alternate power
RS-232 serial

USB Powered
2W maximum consumption
OMAP is small of that
Many adapter options
Car, wall, battery, solar,

Revision C has 256MB LPDDR RAM
6
And more

On-going collaboration at BeagleBoard.org
Live chat via IRC for 24/7 community support
Links to software projects to download

Other Features
4 LEDs
USR0
USR1
PMU_STAT
PWR
2 buttons
USER
RESET
4 boot sources
SD/MMC
NAND flash
USB
Serial

Peripheral I/O
DVI-D video out
SD/MMC
S-Video out
USB HS on-the-go
I2C, I2S, SPI,MMC/SD
JTAG
Stereo in/out
Alternate power
RS-232 serial

7
New for Revision C
3

Peripheral I/O
USB HS/host-only(in addition to existingUSB HS
on-the-go)
LCD expansion

256MB LPDDR RAM (up from 128MB)
8
Desktop development
Note Beagle Boardcan be powered fromthe
alternate jack (as shown) or via USB
9
Development on-the-go
10
Expand with custom hardware
USRP
Stereo out
USB
Power
SD2GB
Photo by Philip Balister
10
11
Typical peripherals

Available from Digi-Key
Serial cable (BBC01-ND)
Needed for serial console
HDMI-to-DVI-D cable (AE10260-ND)
Needed for connection to digital monitors
USB hub (DA-70227-ND)
Needed for adding USB peripherals
5V power supply (T450-P5P-ND)
Frees USB OTG port
Hardware specifications and recommended
peripherals
http//BeagleBoard.org/hardware
RSS feed of newly verified peripherals
http//feeds.feedburner.com/BeagleBoardPeripherals

12
Other design benefitshttp//beagleboard.org/hardw
are/design

Open source hardware design
Low power
No fan for silent operation
Use a USB cable to power the board (barrel
connector power option)
USB 2.0 high-speed on-the-go (OTG) and host-only
(EHCI) ports
Host an almost endless set of USB peripheral
devices
On-the go port
Acts as device when connected to a PC and
host when connected to a hub
OTG port requires a mini-A to standard-A adapter
to act as a host http//BeagleBoard.org/hardware
Able to emulate a network connection to a PC
Provides power to board
Boot options
Boot from NAND, MMC/SD, serial, or USB using
OMAP3530 ROM
User button
Boot default NAND ? USB ? serial ? MMC/SD
Button pressed USB ? serial ? MMC/SD ? NAND
Avoids bricking
Reusable in applications
Reset button (function may be altered with
software)

13
Verifying the hardware

Code images, procedure, and sources are provided
to verify the board functionality
Links to the diagnostics found at
http//BeagleBoard.org/support
Includes bootloader, Linux kernel, and minimal
file system for testing
These sources act as examples for software
developers

14
Baseline tools and softwarehttp//beagleboard.org
/resources

Hardware verification procedure
(http//beagleboard.org.support)
Code images, procedure, and sources are provided
to verify the board functionality
GPL ARM GNU compiler collection
Code Sourcery version 2007q3 is one known-good
option
Runs on Linux/Windows and generates ARMv7/Thumb2
Free C6000 compiler for non-commercial use
x86-Linux hosted
GPL x-load version 1.4.2
GPL u-boot version 2009.01
Interact over UART or USB and program flash
Boot kernel from UART, NAND, or MMC/SD (FAT32)
Test UART, DVI-D, S-Video, NAND, and MMC/SD
GPL Linux kernel version 2.6.28 for diagnostics
Test UART, DVI-D, S-Video, ALSA audio, NAND,
MMC/SD, USB OTG, and USB Host
Free 3D graphics libraries (OpenGLES 2.0)
BSD/GPL DSP interface software
Free production audio/video codecs for the DSP

15
BeagleBoard.org

Four primary activities
Buy a board
Learn how to use existing projects
Learn how to join or start a project
Learn about the latest project news
Plans for site
Multi-lingual
Wiki-like editing-through-web
Keep website source open leverage OpenID

Facilitates community
Aggregates blogs
Provides community chat
Of, by, and for members
Promotes member actions
OMAP3530 collaboration
Focus upstream
Long-term presence
Broad set of problems
Aggregate downstream
Inform users of the broader world
Avoid information deluge

16
Community projects and distroshttp//www.flickr.c
om/groups/beagleboard/pool/ and
http//beagleboad.org/project

Ångström Linux Distribution
Firefox 3.0, Epiphany-WebKit, etc.
AbiWord, GIMP, etc.
3D graphics and DSP codec integration
ARMv7NEON gcc tool-chain
Maemo.org
FFmpeg
720P-24 MPEG4 decode on ARMNEON only
Beagle SDR (low-power software defined radio)
Windows Embedded for BeagleBoard
Handheld.orgs Mojo Ubuntu build for ARM
Android for Beagle
ARM Linux Internet Platform
Ubuntu, Debian, OpenOCD, Mamona, Ethernet, OKL4,
robots, home automation, vision, e-ink displays,
FreeBSD, QEMU, Fedora,
Kernel, boot-loader, and boot utilities
Several more and growing

17
A handful of the thousands
Camera streaming application
Audio processing
Linux home fileserver
VLC VideoLAN
Fanless multimedia/internet terminal
Low-cost kiosk terminal
Wearable computer
Development platform for mobile VoIP phone
CMUcam-style applications
Low cost linux pc/gaming device
Smart home
Bluez and GUI using direct frame buffering
I'm interested to buy 2 to 10 rev-B boards (10
preferred ) congratulations for your project
and its spirit !
LCD picture frame
Linux thin client
Port xnu
Autonomous robot
Port OpenWrt
Port Google-Android
Networked digital signage
Processing images and pattern recognition
Home monitoring
No idea yet
Small linux home fileserver
I'm not interested in waiting for the platform to
mature any longer. Let me know how to get hold
of a beagleboard now.
Port OpenMoko
Mobile DTV tuner and receiver
Port OKL4
Clutter Qt development
Powerful nas with media server and transcoding
capabilities
Autonomous vehicles
Home security cameras and powered-curtains
After discussing with my dev guys, I confirm I
would like to order 20 beagleboards
Bachelor thesis
I'd like my students to design and build hardware
and software to do for Linux what TimeCapsule
does for MacOS
Media centre
SDR platform
Speech recognition applications
Vehicle telematics
Linux/Firefox web add-on for the TV in the house
Project for masters degree
18
Booting the Beagle Board
19
Equipment at ESC Boston

For you to keep
Beagle Board Rev. C3
SD card
Content for each class
Serial cable
IDC10-to-DB9 adapter
Null modem cable
Hub
Powered USB 2.0 HS
Cables
USB to Beagle power
HDMI to DVI-D
USB A to mini-B
For you to use in the labs
DVI-D monitor
USB keyboard and mouse

Powered USB hub
USBPower
DVI-DMonitor
SD
Desktop Computer Configuration
20
First boot of 101 image

Connect everything and then apply power
Image boots up as root by default
Applications?Settings?Login Setup
Dont do the next step yet!
Start root terminal and use /switchboot to
start other images
Use halt to power down (optional?)

opkg install font-misc-misc xterm -fn 10x20
21
Default boot behavior
RESET
Is USER pressed?
Poll USB, Serial, and SD before trying NAND
Is u-boot.bin on SD card?
Run u-boot.bin from SD card, possibly ignoring
environment
Is env var set?
Execute commands stored in bootcmd environment
var
Execute default commands
22
The five (5) boot phases

ROM loads x-load (MLO)
X-load loads u-boot
U-boot reads commands
Commands load kernel
Kernel reads root file system

MLO 0x000000 U-boot 0x020000 Env
0x260000 Kernel 0x280000 File sys 0x680000
23
(1) ROM loads x-load (MLO)http//www.ti.com/litv/
pdf/sprufd6a

ROM attempts to load boot image
Sequence of attempts depends if USER button
pressed
Not-pressed NAND?USB?serial?MMC/SD
Pressed USB?serial?MMC/SD?NAND
For MMC/SD boot
Must have 255 heads and 63 sectors/track
First partition is FAT and bootable
Must have MLO as first file and directory entry
MLO is x-load.bin.ift renamed
X-load image must be signed
signGP app is open source
There are utilities for USB and serial boot

24
(2) X-load loads u-boothttp//gitorious.org/proje
cts/x-load-omap3

X-load is a utility derived from u-boot
Small enough to fit in internal RAM
Configures external RAM
Only configured to read NAND or MMC/SD
X-load 1.4.2 looks first on MMC/SD
If it finds u-boot.bin, loads and runs it
Otherwise loads u-boot from the second NAND
partition (mtd1)

25
(3) U-boot reads commandshttp//gitorious.org/pro
jects/u-boot-omap3

U-boot version allows interaction over the serial
and USB ports
Serial cable provided in case you have a laptop
USB driver looks like a USB-to-serial converter
device
Use gserial.inf to install a driver in Windows
U-boot environment variables read from flash
Stored in the third flash partition (mtd2)
bootcmd variable stores the commands to execute
bootdelay is number of seconds to allow
interruption of the boot
Default bootcmd reads boot.scr auto-script

26
(4) Commands load kernel

U-boot loads kernel and passes it bootargs
Default environment is used when variables
havent been stored in flash
Rev C boards are shipped without variables stored
in flash
Console can be used to interrupt the boot process
and modify variables
The Rev B u-boot only supported the console over
the serial port
The Rev C u-boot adds support for the console
over the USB OTG port
Future modifications may support USB
keyboard/mouse and DVI-D monitor
Fourth flash partition (mtd3) is reserved for the
kernel
bootm ltRAM addrgt executes kernel from RAM

27
Default bootcmd for Rev Chttp//gitorious.org/pro
jects/beagleboard-default-u-boot/repos/jason-clone
/blobs/for-khasim-rebase/include/configs/omap3_bea
gle.h

bootcmdif mmcinit then if run
loadbootscript then run bootscript else
if run loaduimage then if run
loadramdisk then run ramboot else
run mmcboot fi else run nandboot
fi fi else run nandboot fi

28
U-boot command summaryhttp//www.denx.de/wiki/DUL
G/Manual

Basic commands
help provide the list of commands (varies by
build)
printenv lists the contents of the current
environment
saveenv writes the current environment to the
flash
setenv ltvariablegt string sets environment
variable
autoscr ltRAM addrgt run script from RAM
MMC/SD
mmcinit initializes the MMC/SD card
fatls mmc 0 reads FAT directory on the first
partition
fatload mmc 0 ltRAM addrgt ltfilenamegt load a file
into RAM
NAND
nand unlock enables writing to the NAND
nandecc ltswhwgt configures ECC mode (OMAP3
specific)
nand erase ltstartgt ltlengthgt erases portion of
NAND flash
nand read ltRAM addrgt ltstartgt ltlengthgt reads
into RAM
nand write ltRAM addrgt ltstartgt ltlengthgt writes
from RAM
Serial
loadb ltRAM addrgt reads into RAM via kermit file
send

29
(5) Kernel reads root file system

Kernel mounts root file system based on
bootargs
NAND (JFFS2) root/dev/mtdblock4 rw
rootfstypejffs2
RAMDISK root/dev/ram0 rw ramdisk_size32768
initrd0x81600000,32M
MMC/SD root/dev/mmcblk0p2 rw rootwait
NFS root/dev/nfs rw nfsroot192.168.123.1/data/
target ip192.168.123.2255.255.255.0
nolock,rsize1024,wsize1024 rootdelay2

30
Configuring the displayhttp//groups.google.com/g
roup/beagleboard/msg/4c64b2c614622053

videoomapfb
vram10M
omap-dss.def_displcd
omapfb.vram4M,3M,3M
omapfb.video_mode1024x768MR-16_at_60

31
Other bootargs

nohzoff
Power management
mem88M
Reserve memory

32
Some simple tests

Understanding the basics of Linux

33
Getting started with Linux

Starting references
http//free-electrons/training
http//kernelnewbies.org (/UpstreamMerge)
The Linux Documentation Project
(http//www.tldp.org/)
Device Drivers Book (http//www.xml.com/ldd/chapte
r/book/index.html)
http//kerneltrap.org
The kernel GitWeb
http//git.kernel.org/?plinux/kernel/git/torvalds
/linux-2.6.git
Linux-omap kernel
http//linux.omap.com
http//source.mvista.com/git/ (Tony Lindgren)
Others that feed the kernel or linux-omap
kernel
http//www.linux-arm.org/git?plinux-2.6.git
http//www.arm.linux.org.uk/
http//www.sakoman.net/cgi-bin/gitweb.cgi

34
Everything is a file http//free-electrons.com/do
c/unix_linux_introduction.pdf

In Linux, you typically talk to devices using
file I/O
GPIO example
ls /sys ls /proc cat /proc/cmdline
echo none gt /sys/class/leds/beagleboard\\usr0/
trigger
echo 1 gt /sys/class/leds/beagleboard\\usr0/bri
ghtness
echo 0 gt /sys/class/leds/beagleboard\\usr0/bri
ghtness
echo heartbeat gt /sys/class/leds/beagleboard\\
usr0/trigger

35
Read eventshttp//git.kernel.org/?plinux/kernel/
git/torvalds/linux-2.6.gitablobfDocumentation/
input/input.txt

cd /utils
gcc -o evtest evtest.c
./evtest /dev/input/event0
Press the USER button
C to exit
./evtest /dev/input/event4
Move the mouse
C to exit

36
Access monitor EDID

cd /sys/bus ls cd
cat /sys/bus/i2c/devices/3-0050/eeprom
i2cdump -y 0x3 0x50 b
decode-edid
fbset

37
USB OTG and EHCI

cd /sys/bus/usb/devices
ls
cat usb1/speed
cat usb1/1-2/1-2.2/manufacturer
cd
lsusb

38
Networking

Copy linux.inf from SD card to host and connect
Beagle
ifconfig
nano /etc/networking/interfaces
ifdown usb0 ifup usb0
ifconfig
Configure your host using linux.inf
ping 192.168.123.1
VNC
x11vnc
Connect with your VNC viewer from your host
Synergy
Start Synergy server on your host
synergyc --daemon --restart 192.168.123.1

39
Writing our own boot script
40
Build u-boot and mkimage

cd /u-boot-omap3
make omap3_beagle_config
make

41
Build my.scr

cd /u-boot-omap3
cp /media/mmcblk0p1/menu/kridner.script my.script
nano my.script
./tools/mkimage -A arm -T script -C none -d
my.script my.scr
Be very careful before executing the next step
cp my.scr /media/mmcblk0p1/boot.scr
If unsure, run /switchboot now
boot

42
Edit environment in flash

make env
nano /etc/fw_env.config
/dev/mtd2 0 0x20000 0x20000
./tools/env/fw_printenv
ln -s tools/env/fw_printenv fw_setenv
./fw_setenv usbtty cdc_acm
./fw_setenv stdout serial,usbtty
./fw_setenv stdin serial,usbtty
./fw_setenv stderr serial,usbtty
./tools/env/fw_printenv

43
Trying usbtty

cp /gserial.inf /media/mmcblk0p1/
halt
Remove power and SD card
Copy gserial.inf from SD to PC
Plug USB from Beagle to your PC
Select driver
Start Hyperterminal
Newest serial port, max baud, n81, no flow
Optional
nand erase 0x260000 0x20000

44
Creating a ramdisk.gz

dd if/dev/zero oframdisk bs1k count32768
mkfs.ext2 ramdisk
mount -o loop ramdisk /mnt
tar -xvjf fs.tar.bz2 -C /mnt
Other methods to copy may be fine
umount /mnt
gzip ramdisk

45
Native, managed, and web-based UI code development
46
Native development

Not limited to embedded/cross tools
Reach out to broader developer community
Native tools easy to install
Immediately see impact of your changes
Edit local source files with familiar editors
You still need to manage your code!
Version control with git, svn, cvs,
Also possible to perform distributed builds
Some packages may require larger memory

47
Managed code

Easier to create an emulation environment
But what about performance?
JIT compilers may be sufficient
Performance bottlenecks are often in just a few
places
Just optimize where the issue is, but build the
rest fast!
Important to make sure the rest is open for
optimization
Certainly not for every market
If you already know C/GTK/Qt, use what you know!
If you are new, this may be a way to get started

48
Web-based UI developmenthttp//www.programmablewe
b.com/scorecard

Familiar paradigm for consumers
Enables remote control and monitoring
Many HTML/JavaScript developers
Opens up use of other web services
Mapping
Order fulfillment
Storage
Social networking and media

49
Web-based UI development

Helma is one option for the server side
Based on Java Servlet Container and Mozilla Rhino
Provides sessions, user management,
Write entire applications in XML/HTML and
JavaScript
No recompilation required, allowing for dynamic
development
Database options for object storage with
automatic persistence
Native XML database for flexibility
Java database connection (JDBC) for scale
Drop-in Java .jar files for access to huge
libraries of functions
Accessing Linux shell and drivers
rtPackages.java.lang.Runtime.getRuntime()
rt.exec()
new Packages.java.io.File()

50
Beagle web control demo

beagle-web-control-demo used at ARM Developers
Conferencehttp//www.beagleboard.org/gitweb/?pbe
agle-web-control-demo.gitasummary
cd
If not root sudo ./beagle-web-control-demo/script
/permissions.sh
./helma-1.6.1/start.sh
tail -f helma-1.6.1/log/helma.beaglewebcontroldemo
.event.log
Browse (using Midori) to
http//localhost8080/demo/static/ARM_DevCon/slide
34.html
Turn LEDs on and off

51
Collaboration tools
52
Distributed version control

GIT is differenteliminates often bad assumptions
Instead of everyone pushing into Linus
repository
Linus pulls patches from people he trusts
Everyone has all of Linus history (and their
own) locally
Patches enter system as e-mail messages
When a merge is non-trivial, he simply asks
others to rebase
Mailing list
Archives available to everyone
Accepted patches applied to git repositories
Guides to GIT
http//linux.yyz.us/git-howto.html
http//git.or.cz/
http//www.kernel.org/pub/software/scm/git/docs/

53
Post patch to OMAP community

Readhttp//www.muru.com/linux/omap/README_OMAP_PA
TCHES
Post your patch to mailing listlinux-omap_at_vger.ke
rnel.org

54
Chat, mail, forums, blogs, and wikis!

All exist because they all solve different
problems
Chat allows you to know someones
listeninghttp//beagleboard.org/chat or beagle
on irc.freenode.net
Great for beginner questions and rapid
coordination
Mail allows you to reach almost
anyonehttp//groups.google.com/group/beagleboard
Brings larger group into the conversation
Provides you with a personal log in your inbox
Forums helps get the threads organizedhttps//com
munity.ti.com/forums/32.aspx (minimal activity to
avoid disrupting community critical mass)
Blogs provide emphasis, filtering, and
timelinesshttp//beagleboard.org/news and
http//beagleboard.blogspot.com
Wikis enable inputs to become documentationhttp/
/eLinux.org/BeagleBoard and http//code.google.com
/p/beagleboard/wiki

55
Chat on IRC

http//freenode.net
beagle discussion regarding the Beagle Board
neuros discussion
davinci discussion regarding TI DaVinci
products
ol discussion regarding OMAP Linux (not active)
IRC clients
http//beagleboard.org/chat
http//pidgin.im
http//www.mirc.com
http//en.wikipedia.org/wiki/List_of_IRC_clients
http//www.ircreviews.org/clients/

56
E-mail regarding OMAP Linux

http//BeagleBoard.org/discuss
http//vger.kernel.org/vger-lists.htmllinux-omap

57
Forums

http//community.ti.com

58
Blogs (RSS feeds)

http//beagleboard.blogspot.com

59
Wikis

http//wiki.davincidsp.com
http//tiexpressdsp.com
http//elinux.org/BeagleBoard

60
Registering Beagle projectshttp//code.google.com

Anyone can create a new open source project
Features
Site is cleaner than sf.net, but sf.net is OK
too
Source control is Subversion
Issue tracking is custom
Provides downloads and wiki support
Use common sense and get your managers approval
Use the tag beagleboard
Lets explore http//code.google.com/p/beagleboar
d

61
Git

What is Git?
Git is a popular version control system designed
to handle very large projects with speed and
efficiency it is used mainly for various open
source projects, most notably the Linux kernel.
Git falls in the category of distributed source
code management tools, similar to e.g. GNU Arch
or Monotone (or BitKeeper in the proprietary
world). Every Git working directory is a
full-fledged repository with full revision
tracking capabilities, not dependent on network
access or a central server.
Git is an Open Source project covered by the GNU
General Public License v2. It was originally
written by Linus Torvalds and is currently
maintained by Junio C Hamano.
Read more here
http//git.or.cz/
Learn from Linus here
http//www.youtube.com/watch?v4XpnKHJAok8

62
Community Participation with Git
63
Features of Git

Strong support for non-linear development
Git supports rapid and convenient branching and
merging
Includes powerful tools for visualizing and
navigating a non-linear development history
Distributed development
Remote changes are imported as additional
development branches and can be merged in the
same way as a locally developed branch
Repositories can be easily accessed via the
efficient Git protocol (optionally under ssh) or
HTTP
No special web server configuration required
Efficient handling of large projects
Very fast and scales well even when working with
large projects and long histories
Commonly an order of magnitude faster
Extremely efficient packed format for long-term
revision storage
Cryptographic authentication of history
History is stored in such a way that the name of
a particular revision (a "commit" in Git terms)
depends upon the complete development history
leading up to that commit
Once published, it is not possible to change the
old versions without it being noticed
Tags can be cryptographically signed
Toolkit design
Following the Unix tradition, Git is a collection
of many small tools written in C, and a number of
scripts that provide convenient wrappers
Easy to chain components together to do other
clever things

64
How to build Git tool from source
Download GIT from http//git.or.cz/
How to build GIT ? gt tar xzvf
git-1.5.5.1.tar.gz gt cd ltto extracted
directorygt gt make How to install GIT ? gt make
prefixltmy directorygt install Example gt make
prefix/home/ubuntu/mygit/ install GIT tools
will be installed at /home/ubuntu/mygit/bin
(export this PATH to get the GIT commands)
65
Commands used to pull trees

Refer to Tonys README on muru.com for detailed
description on working with OMAP GIT
tree.
http//www.muru.com/linux/omap/README_OMAP_GIT
Few important commands
To clone OMAP GIT Tree
git clone http//www.kernel.org/pub/scm/linux/k
ernel/git/tmlind/linux-omap-2.6.git
Note Setup Proxy Server before cloning the
tree
Example gt export http_proxyhttp//my.proxy.he
report/
To re-sync your branch with mainline
git-pull

66
What do you do with Git?

To add new changes
Open file in any unix compatible editor.
Do the modifications
Save the file
To store the file in repository
git status
git update-index arch/arm/plat-omap/myfile.c
git commit -s
To generate patches using GIT tool
git format-patch -o ltoutput_dirgt
abcdef0123456789abcdef0123456789abcdef01
Other methods
- Create another local branch and take a normal
diff between the too.
- Use Quilt. (http//download.savannah.gnu.org/re
leases/quilt/)

67
Everyday Githttp//www.kernel.org/pub/software/sc
m/git/docs/everyday.html

git-show-branch(1) to see where you are.
git-log(1) to see what happened.
git-checkout(1) and git-branch(1) to switch
branches.
git-add(1) to manage the index file.
git-diff(1) and git-status(1) to see what you are
in the middle of doing.
git-commit(1) to advance the current branch.
git-reset(1) and git-checkout(1) (with pathname
parameters) to undo changes.
git-merge(1) to merge between local branches.
git-rebase(1) to maintain topic branches.
git-tag(1) to mark known point.

68
Community participation with Open Embedded
69
What is Open Embedded (OE)?http//www.openembedde
d.org

OE is like a top-level Makefile
Sophisticated layer on top of make
Tool for building distributions
Maintains meta-data database for building open
source
BitBake is a python tool core to OE
Database is built of recipes for each package
Inheritance for reuse (autotools, )
Satisfies dependencies and follows build steps
Fetch, unpack, patch, configure, compile, stage,
install, package
Opkg tool for package management
Replacement for Debian dpkg
Utilizes pre-built package feeds

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What role does OE play?

Collaboration on entire distribution
Ångstrøm is a distribution built with OE
Full control over almost every aspect
Tool chain, package set, patches, kernel,...
Relatively complete starting point
armv7a compiled binaries in Ångstrøm
Possible to take a demo snapshot
Play with higher-level development

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What does Ångstrøm provide today?http//beagleboa
rd.org/project/angstrom

Browsers
Gecko Firefox 3, Fennec,
WebKit Epiphany,
Media
FFmpeg, XMMS, GStreamer, MythTV,
Development
C, Java, Python, Perl, Mono, Ruby, Tk,
Gaming, Networking,

http//www.angstrom-distribution.org/repo/
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Installing Ångstrøm to NANDhttp//beagleboard.org
/demo/angstrom

SD card FAT formatted (default, optionally
bootable)
boot/kernel/ramdisk to get into OE console
Can store kernel (and ramdisk) in flash
Copy of tar.bz2 of full file system image desired
Boot console image
bootargs consolettyS2,115200n8
ramdisk_size32768 root/dev/ram0 rw
rootfstypeext2 initrd0x81600000,32M
bootcmd mmcinitfatload mmc 0 80300000
uImagefatload mmc 0 81600000 angstrom-console-rd
.gz
Flash board
opkg install mtd-utils opkg install mkfs-jffs2
flash_eraseall /dev/mtd4 mkfs.jffs2 -o
/dev/mtdblock4
mkdir /mnt/flash mount -t jffs2 /dev/mtdblock4
/mnt/flash
tar xvjf Angstrom-XXX.rootfs.tar.bz2 -C
/mnt/flash
Boot new file system
bootargs consolettyS2,115200n8 consoletty0
root/dev/mtdblock4 rw rootfstypejffs2 nohzoff
videoomapfbvram2M,vram4M
bootcmd nand read 80200000 280000 400000 bootm
80200000

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What is Open Embedded made from?

BitBake build tool
Specifically written for top level make problem
space
Uses inheritance to factor common support from
recipes
Simple language with shell sequences
Language elements and functions can use Python
for advanced cases
Meta-data
Package recipes and classes
A number of distribution definitions
A number of platform definitions
A version control repository of the meta-data
Uses Monotone for SCM (moving to Git)
Maintains dev and (recently) stable branches

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OE reference typical processing

Satisfy all dependencies
Build (default command)
Fetch get the source code
Unpack extract the source code
Patch apply patches (local or fetched)
Configure run any configuration steps
Compile do actual compilation
Stage install locally for use by other packages
Install install product files to temporary
directory
Package take installed files and place into
packages
helloworld, helloworld-dbg, helloworld-dev,
helloworld-doc, helloworld-local

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Top Level Default OE flow

Build toolchain and libraries
Build needed components to packages
Build file-system image from packages
Will take Gigabytes of storage and hours to
perform the above on a clean install

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Alternate OE flows

Use precompiled toolchain
Use pre-downloaded source archives
Build toolchain and package as an SDK
Build collection of packages only
Build file-system image from pre-built
packages
This may not be a current capability

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What is OE not good for (today) ?

Active development of a given component
There are ways to use OE in this fashion but it
is not a strength and you can lose code if you
are not careful
GUI tools to guide and monitor
All config is edit of text files
Build log is very verbose and not visually
structured

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Limitations and alternatives

Limitations
Build environment not always well isolated
Many build scripts do native build environment
tests
Alternatives
Matrix
Sponsored by ARM http//linux.onarm.com
Utilizes Scratchbox and QEMU
Reproduces target environment in cross-compile
Relies on emulation on build host
Mamona
Targets Nokia Internet Tablets
Utilizes Open Embedded, Scratchbox, and QEMU
Generates Debian source/binary packages
Solves some partial emulation problems
Native development or managed code environments

79
Resources for more information and support
80
Some hardware optionshttp//wiki.omap.com/index.
php?titleOMAP3_Boards

TI/Mistral OMAP35x EVM
Nokia Internet Tablets
LogicPD OMAPZoom
Gumstix Overo
Analogue Micro Cobra3530
Cogent CSB740

Not to scale. Approximate size noted (in inches)
81
Many tools optionshttp//focus.ti.com/dsp/docs/ds
pplatformscontenttp.tsp?sectionId2familyId1525
tabId2224
The many OS vendors for are OMAP35x not listed
here
Tool / Top features Debug Compile Other
TI Code Composer Studio Low-level ARM and DSP Low-level ARM (ARMv7) and DSP (NEON roadmap) Power-aware debug
ARM RealView Low-level ARM Application-level ARM (ARMv7, NEON)
Lauterbach Low-level and app ARM and DSP None Extensive trace
Green Hills Low-level and app ARM and DSP Low-level ARM Trace
CodeSourcery Linux application debug Linux kernel/app ARM (ARMv7, NEON)
Additional third party information here

Cortex-A8 uses ARMv7 instructions

82
OS vendors for OMAP35x

MontaVista
RidgeRun
TimeSys
bSquare
QNX
Many, many more

83
TI OMAP35x software architecturehttp//www.ti.com
/omap35x
Applications
GUI
App Framework
2D/3D APIs
MultimediaFramework
OptionalDRM
GFX Driver
Codec Engine and Link
Codec Engine
FC
BIOS
Linux Kernel / WinCE Power Management
audio
video
image
video
image
audio
video
image
audio
C64x DSP and Video Acceleration
ARM
GFX
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Accessing the C64x DSP

OMAP/DaVinci Dummies Bookhttp//www.ti.com/dumm
iesbook
DSP/BIOS Link source availablehttp//tiexpressds
p.com
Provides code loading and data passing
Kernel portions licensed as GPL
DSP/BIOS RTOS and componentshttp//tiexpressdsp.c
om
Enables sharing of the DSP as a resource
Free TI DSP compilerhttps//www-a.ti.com/download
s/sds_support/targetcontent/LinuxDspTools/index.ht
ml
Non-commercial use
Full support in Code Composer Studiohttp//www.ti
.com/expressdsp

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The Beagle Board community

Support for this board is provided through an
active community of hobbyists and developers
Being very open enables developers to share
Keeps costs low
Enables more people to participate
24/7 access to fellow developers
http//BeagleBoard.org/discuss
Ask your questions before you buy
Participate and enjoy!

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Participating in the community

Joining the herd of catshttp//lwn.net/talks/elc2
007
Building Community for your open source
projecthttp//www.eclipsecon.org/2006/Sub.do?id2
68
Video of Greg Kroah-Hartman on the Linux
kernelhttp//www.linuxelectrons.com/news/linux/16
774/greg-kroah-hartman-linux-kernel
Sending kernel patches upstreamhttp//wiki.omap.c
om/index.php?titlePatch_upstream_sending

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Summary