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[[Category:ECE497]]
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[[Category:ECE497 |Tips]]
 
{{YoderHead}}
 
{{YoderHead}}
  
 
Some useful tips and tricks for Linux and the Beagleboard.
 
Some useful tips and tricks for Linux and the Beagleboard.
 +
 +
== Interesting Links ==
 +
 +
Since we are working with the open source community, you need to know where the action is.  Here are some useful links to what's happening in the Beagle community.
 +
 +
* [http://learn.adafruit.com/category/beaglebone Adafruit's BeagleBone] site.
 +
* [http://groups.google.com/group/beagleboard/browse_thread/thread/c5a631c6582119b8 State of the Beagle 2011], learn about the Beagle's past, present and future.
 +
* [http://BeagleBoard.org BeagleBoard.org], the starting point for all thing Beagle.
 +
* [http://groups.google.com/group/beagleboard Beagle Discussion Group], lot's of good information here, but you'll have to dig a bit.  Subscribe and follow the discussion.
 +
* [http://beagleboard.blogspot.com/ blogspot], see what is being said about the Beagle.
 +
* [http://elinux.org/BeagleBoard eLinux], this is where this page is being hosted.  It's about embedded Linux in general, not just the BeagleBoard.
 +
* [http://free-electrons.com/blog/beagle-labs/ Free Electrons Beagle Board Training], some good labs about what makes embedded Linux run.
 +
* [https://gforge.ti.com/gf/project/tiesr/ TI Embedded Speech Recognizer] (TIesr) is a fixed-point recognizer written in C++ and C.
 +
* [http://code.google.com/soc/ Google Summer of Code].  BeagleBoard is an accepted organization.
 +
* [http://www.makelinux.net/kernel_map Linux Kernel Map]
 +
* [http://processors.wiki.ti.com/index.php/Category:OMAP35x Texas Instruments Embedded Processors Wiki]
  
 
== Linux ==
 
== Linux ==
  
 
[http://freeengineer.org/learnUNIXin10minutes.html Learn UNIX in 10 Minutes] is a quick overview of the most commonly used Linux commands.
 
[http://freeengineer.org/learnUNIXin10minutes.html Learn UNIX in 10 Minutes] is a quick overview of the most commonly used Linux commands.
 +
 +
[http://lifehacker.com/5935869/top-10-tools-that-are-better-in-the-command-line?utm_campaign=socialflow_lifehacker_twitter&utm_source=lifehacker_twitter&utm_medium=socialflow Top 10 Tools] is a nice summary of 10 of the most useful Linux commands.
  
 
=== Quick Tips ===
 
=== Quick Tips ===
Line 15: Line 33:
 
! Description
 
! Description
 
|-
 
|-
| <pre>$ gnome-open</pre>
+
|  
 +
beagle$ '''gnome-open'''
 
| Open a file or directory using the default program
 
| Open a file or directory using the default program
 
|-
 
|-
Line 24: Line 43:
 
| If you invoke gdb with the command line argument -tui, it will show a built-in GUI
 
| If you invoke gdb with the command line argument -tui, it will show a built-in GUI
 
|-
 
|-
| <pre>$ ntpdate pool.ntp.org</pre>
+
|  
| This will go to a '''n'''etwork '''t'''ime '''p'''rotocol server and get the current time and set the Beagle to it.
+
beagle$ '''ntpdate ntp.org'''
 +
beagle$ '''rm /etc/localtime'''
 +
beagle$ '''ln -s /usr/share/zoneinfo/America/New_York /etc/localtime'''
 +
 
 +
| This will go to a '''n'''etwork '''t'''ime '''p'''rotocol server and get the current time and set the Beagle to it and set the local time zone. [http://derekmolloy.ie/automatically-setting-the-beaglebone-black-time-using-ntp/]
 +
|-
 +
|
 +
beagle$ '''mount -t debugfs debugfs /sys/kernel/debug/'''
 +
beagle$ '''cd /sys/kernel/debug'''
 +
beagle$ '''ls'''
 +
| Kernel Debug Info
 
|}
 
|}
 +
 +
=== Connecting to RHIT wifi ===
 +
 +
There is a discussion in the [https://groups.google.com/forum/?fromgroups=#!topic/beaglebone/9PEUmcsLXLU Beagle Google Group] about getting wireless working with the bone.
 +
 +
Use these settings for connecting to the Rose-Hulman wireless network:
 +
 +
* '''SSID:''' RHIT-1X
 +
* '''Security:''' WPA & WPA2 Enterprise
 +
* Leave "anonymous identity" blank
 +
* '''CA Certificate''': (None)
 +
* '''PEAP version''': Version 0
 +
* '''Inner authentication''': MSCHAPv2
 +
* Use your Rose username and password
  
 
=== bash ===
 
=== bash ===
Line 55: Line 98:
 
When using ssh between to X-windows systems try
 
When using ssh between to X-windows systems try
  
<pre>
+
host$ '''ssh -CX root@beagle'''
host$ ssh -CX root@beagle
+
 
</pre>
+
 
The -X set the DISPLAY variable on the remote machine so you can open windows from the beagle on your host machine.   
 
The -X set the DISPLAY variable on the remote machine so you can open windows from the beagle on your host machine.   
  
Line 65: Line 107:
  
 
You can run a vnc server on the Beagle.  Install it with:
 
You can run a vnc server on the Beagle.  Install it with:
  $ opkg update
+
  beagle$ '''opkg update'''
  $ opkg install x11vnc
+
  beagle$ '''opkg install x11vnc'''
 
Install a password with
 
Install a password with
  $ x11vnc -storepasswd
+
  beagle$ '''x11vnc -storepasswd'''
 
Run it on the Beagle with
 
Run it on the Beagle with
  $ x11vnc -display :0 -ssl -usepw -forever -q &
+
  beagle$ '''x11vnc -display :0 -ssl -usepw -forever -q &'''
 
On your host, connect to it with:
 
On your host, connect to it with:
  host $ vinagre
+
  host$ '''vinagre'''
 
or '''Applications:Internet:Remote Desktop Viewer'''
 
or '''Applications:Internet:Remote Desktop Viewer'''
  
 
==== Authorizing ssh ====
 
==== Authorizing ssh ====
  
<span style="color:red">Note: This isn't currently working for me.</span>
+
'''ssh''' and '''scp''' can be set up for automatic authorization so you don't have to enter your password when using these commands. Here's how to do it.
 +
First let's see what's already there:
  
'''ssh''' and '''scp''' can be set up for automatic authorization so you don't have to enter your password when using these commands. Here's how to do it:
+
* On your Beagle run
 +
 
 +
beagle$ '''ls ~/.ssh'''
 +
 
 +
'''~/.ssh''' may not exist, if not, it will be created. If it's there, check the files in it.
  
 
* On your host computer run
 
* On your host computer run
<pre>
 
host $ ssh-keygen
 
host $ cd ~/.ssh
 
host $ scp id_rsa root@beagle:.
 
host $ ssh beagle
 
</pre>
 
The first command creates an authorization key and places it in your .ssh directory.  Remember the pass phrase you enter here.  You'll use it below.  The next two commands copy that key to your Beagle.  The last command connects to your Beagle.
 
* On your Beagle run
 
<pre>
 
beagle $ mkdir ~/.ssh
 
beagle $ cd ~/.ssh
 
beagle $ mv ../id_rsa.pub .
 
beagle $ cp id_rsa.pub authorized_keys
 
beagle $ exit
 
</pre>
 
Here we create a '''.ssh''' directory and copy the public key into it.  The authorized_keys folder contains a list of all the machines that are authorized to connect to your Beagle without a password.
 
* Back on the host computer:
 
<pre>
 
host $ ssh -CX root@beagle
 
</pre>
 
This time you should see a window pop up.  Enter your pass phrase from above.  You should be logged into your Beagle.  Log out and log in again.  This time you should get access without having to enter your pass phrase.
 
  
[http://kimmo.suominen.com/docs/ssh/ Here] is move information on ssh authorization.
+
host$ '''ssh-copy-id root@beagle'''
 +
 
 +
It was ask for you beagle password and then copy the needed files to it.
 +
 
 +
* Back on the beagle to see what has changed:
 +
 
 +
host$ '''ssh -CX root@beagle'''
 +
beagle$ '''ls ~/.ssh'''
 +
 
 +
The ssh command shouldn't ask for a password. What new files appeared?
 +
 
 +
==== ssh configuration ====
 +
 
 +
Here's a nice tip so you don't have to remember who to login as on the beagle. On your host, put the following in '''~/.ssh/config'''.
 +
 
 +
Host beagle
 +
    User root
 +
    UserKnownHostsFile /dev/null
 +
    StrictHostKeyChecking no
 +
 
 +
Before you had to
 +
host$ ssh -CX root@beagle
 +
 
 +
Now you can just
 +
host$ ssh -CX beagle
  
 
=== Mounting dfs/afs ===
 
=== Mounting dfs/afs ===
Line 117: Line 167:
 
</pre>
 
</pre>
 
You'll have to replace <code>username</code> with your login name.  Then create the mount points:
 
You'll have to replace <code>username</code> with your login name.  Then create the mount points:
<pre>
+
 
cd ~
+
host$ '''cd ~'''
mkdir MyDocs
+
host$ '''mkdir MyDocs'''
mkdir dfs-home
+
host$ '''mkdir dfs-home'''
mkdir afs-home
+
host$ '''mkdir afs-home'''
</pre>
+
 
 
Now you can mount your files by using:
 
Now you can mount your files by using:
<pre>
+
 
cd ~
+
host$ '''cd ~'''
mount dfs-home
+
host$ '''mount dfs-home'''
cd dfs-home
+
host$ '''cd dfs-home'''
ls
+
host$ '''ls'''
</pre>
+
 
 
You should now see your dfs files.  You can unmount using:
 
You should now see your dfs files.  You can unmount using:
<pre>
+
 
cd ~
+
host$ '''cd ~'''
sudo umount dfs-home
+
host$ '''sudo umount dfs-home'''
</pre>
+
 
 +
=== debugfs ===
 +
 
 +
'''debugfs''' looks like a handy way to look into the kernel.  These notes are based on the example [https://groups.google.com/forum/#!msg/beagleboard/bGZcCHwHwrI/CXHJ0WOBpV0J here].
 +
 
 +
beagle$ '''cd /'''
 +
beagle$ '''mkdir debugfs'''
 +
beagle$ '''mount -t debugfs none debugfs'''
 +
 
 +
Then explore...
 +
 
 +
bone$ '''cd debugfs; ls -F'''
 +
asoc/  gpio      mmc0/      pm_debug/  sched_features  vram
 +
bdi/    hid/      musb/      regdump    testmode        wakeup_sources
 +
clock/  memblock/  omap_mux/  regulator/  usb/
 +
 
 +
beagle$ ''' cd debugfs; ls -F'''
 +
asoc/  clock/  hid/  omapdss/  sched_features  usb/
 +
bdi/  gpio    mmc0/  pm_debug/  tracing/       vram
  
 
=== Tool chain work flows ===
 
=== Tool chain work flows ===
Line 193: Line 261:
  
 
Install byobu on your host with:
 
Install byobu on your host with:
<pre>
+
 
$ sudo apt-get update
+
host$ '''sudo apt-get update'''
$ sudo apt-get install byobu
+
host$ '''sudo apt-get install byobu'''
</pre>
+
 
 
It's a bit harder on the Beagle.
 
It's a bit harder on the Beagle.
# opkg update
+
beagle$ '''opkg update'''
# opkg install screen
+
beagle$ '''opkg install screen'''
# Go to [https://launchpad.net/byobu/+download here] and download the latest version to your Beagle.
+
Go to [https://launchpad.net/byobu/+download here] and download the latest version to your Beagle.
# Run tar zxvf byobu_*.orig.tar.gz  
+
beagle$ '''tar zxvf byobu_*.orig.tar.gz'''
# cd byobu* and follow the instructions in INSTALL. I had to hack one file.
+
beagle$ '''cd byobu*''' and follow the instructions in INSTALL. I had to hack one file.
# gedit /usr/local/lib/byobu/.constants.  Change the last two lines to:
+
beagle$ '''gedit /usr/local/lib/byobu/.constants'''.   
<pre>
+
 
# command -v gsed >/dev/null && export SED="gsed" || export SED="sed"
+
Change the last two lines to:
# command -v greadlink >/dev/null && export READLINK="greadlink" || export READLINK="readlink"
+
 
export SED="sed"
+
# command -v gsed >/dev/null && export SED="gsed" || export SED="sed"
export READLINK="readlink"
+
# command -v greadlink >/dev/null && export READLINK="greadlink" || export READLINK="readlink"
</pre>
+
export SED="sed"
 +
export READLINK="readlink"
 +
 
 
Now you can run it.
 
Now you can run it.
<pre>
+
 
$ byobu
+
beagle$ '''byobu'''
</pre>
+
 
 
You'll see a command prompt.  You'll also see some status information on the bottom two lines.  Type Ctrl-A ? for help.  Type Ctrl-A Ctrl-D to detach from the session.  Running byobu again will reattach you to the session.  Try running byobu in two windows at the same time.  You should see the same session in both.
 
You'll see a command prompt.  You'll also see some status information on the bottom two lines.  Type Ctrl-A ? for help.  Type Ctrl-A Ctrl-D to detach from the session.  Running byobu again will reattach you to the session.  Try running byobu in two windows at the same time.  You should see the same session in both.
  
Line 220: Line 290:
 
=== Finding what opkg installed ===
 
=== Finding what opkg installed ===
  
Once you've run opkg, how do you know what's been installed?  Take a look in '''/usr/lib/opkg/info'''.  The files that end in .list contain a list of what's been installed.
+
Once you've run opkg, how do you know what's been installed?  Take a look in '''/var/lib/opkg/info''' or '''/usr/lib/opkg/info'''.  The files that end in .list contain a list of what's been installed.
  
 
=== Backing up an SD card with dd ===
 
=== Backing up an SD card with dd ===
Line 226: Line 296:
 
Here's the command I use to backup an SD card. I use '''System:Administration:Disk Utility''' to figure out the path to the card.  In this case it's ''/dev/sdc''
 
Here's the command I use to backup an SD card. I use '''System:Administration:Disk Utility''' to figure out the path to the card.  In this case it's ''/dev/sdc''
  
  $ sudo time dd if=''/dev/sdc'' of=FIE2011.img bs=4M count=1000
+
  host$ '''sudo time dd if=''/dev/sdc'' of=FIE2011.img bs=4M count=1000'''
  $ sudo chown yoder:yoder FIE2011.img
+
  host$ '''sudo chown yoder:yoder FIE2011.img'''
  $ md5sum FIE2011.img > FIE2011.img.md5
+
  host$ '''md5sum FIE2011.img > FIE2011.img.md5'''
  $ bzip2 -k FIE2011.img
+
  host$ '''bzip2 -k FIE2011.img'''
  
 
It takes about 5 minutes to dd a 4G card, 1.2 minutes for md5 and bzip2 takes about 23 minutes.
 
It takes about 5 minutes to dd a 4G card, 1.2 minutes for md5 and bzip2 takes about 23 minutes.
 +
 +
It looks like the 7z compression is becoming popular. Use it via
 +
host$ ''' 7za a FIE2011.img.7z IFE2011.img
 +
 +
It took 16 minutes. The file size is 454M compared to 628M.  Wow, faster and smaller.
  
 
=== CSSE's Linux reference page ===
 
=== CSSE's Linux reference page ===
  
CSSE332, Operating Systems, has a nice page of Linux resources [http://www.rose-hulman.edu/class/csse/csse332/current/Resources/ here].
+
CSSE332, Operating Systems, has a [http://www.rose-hulman.edu/class/csse/csse332/current/Resources/ nice page of Linux resources].
  
 
=== Local Ubuntu Update Mirror ===
 
=== Local Ubuntu Update Mirror ===
Line 245: Line 320:
 
In order to get your system to point to our mirror, please copy and paste this rather lengthy command into a terminal:
 
In order to get your system to point to our mirror, please copy and paste this rather lengthy command into a terminal:
  
<pre>
+
host$ '''sudo cp /etc/apt/sources.list{,.old} && \
sudo cp /etc/apt/sources.list{,.old} && \
+
    sudo sh -c '\
sudo sh -c '\
+
'''. /etc/lsb-release &&'''
. /etc/lsb-release &&
+
'''echo "'''
echo "
+
'''deb http://ftp.csse.rose-hulman.edu/ubuntu $DISTRIB_CODENAME main restricted universe multiverse'''
deb http://ftp.csse.rose-hulman.edu/ubuntu $DISTRIB_CODENAME main restricted universe multiverse
+
'''deb http://ftp.csse.rose-hulman.edu/ubuntu $DISTRIB_CODENAME-updates main restricted universe multiverse'''
deb http://ftp.csse.rose-hulman.edu/ubuntu $DISTRIB_CODENAME-updates main restricted universe multiverse
+
'''deb http://ftp.csse.rose-hulman.edu/ubuntu $DISTRIB_CODENAME-security main restricted universe multiverse'''
deb http://ftp.csse.rose-hulman.edu/ubuntu $DISTRIB_CODENAME-security main restricted universe multiverse
+
'''" > /etc/apt/sources.list' && sudo apt-get update'''
" > /etc/apt/sources.list' && sudo apt-get update
+
</pre>
+
  
 
The text and further instructions are available [http://csse.rose-hulman.edu/news-mainmenu-2/27-linux-distros/102-ubuntu here].
 
The text and further instructions are available [http://csse.rose-hulman.edu/news-mainmenu-2/27-linux-distros/102-ubuntu here].
  
 
The script makes a backup of the updates file and replaces it with links to our mirror. The $DISTRIB_CODENAME is replaced by whatever distro you are running (eg. lucid, maverick, natty etc.). I wish I could take credit for it, but it was a joint effort with Mike McLeish :-)
 
The script makes a backup of the updates file and replaces it with links to our mirror. The $DISTRIB_CODENAME is replaced by whatever distro you are running (eg. lucid, maverick, natty etc.). I wish I could take credit for it, but it was a joint effort with Mike McLeish :-)
 +
 +
=== Using pico DLP with BBB ===
 +
 +
Put this in uEnv.txt to use the BBB with a pico DLP.
 +
optargs=video=HDMI-A-1:640x480@60
  
 
=== More tips ===
 
=== More tips ===
Line 268: Line 346:
 
Most of the work is done under Linux; however there are some handy Windows-based tools.
 
Most of the work is done under Linux; however there are some handy Windows-based tools.
  
=== Tera Term ===
+
=== Serial Port ===
  
[http://www.tucows.com/preview/195282 Tera Term] give you access to the serial port.
+
[http://www.vandyke.com/products/securecrt/ SecureCRT] is a good program that gives you both access to a serial port and is also an ssh client. Rose has a license for [http://www.rose-hulman.edu/tsc/software/documentation/applications/securecrt-secureFX/installation/ SecureCRT].
 +
 
 +
[http://www.tucows.com/preview/195282 Tera Term] also gives you access to the serial port and it's free.
  
 
=== Notepad++ ===
 
=== Notepad++ ===
Line 277: Line 357:
  
 
== Set up on the BeagleBoard ==
 
== Set up on the BeagleBoard ==
 +
 +
=== Setup stuff on github ===
 +
If you've cloned the course github site ([EBC Exercise 05 Getting Exercise Support Materials]]) you will find set up things in '''exercises/setup'''. '''install.sh''' is a list of various things I to to a fresh SD card to 'move in'. For example, the bone will mount a filesystem on the host computer if it's connected via USB.  You can turn this off and have the eithernet over USB run at boot time with:
 +
 +
# Turn off storage gadget, turn on network at boot time.
 +
cd /lib/systemd/system/basic.target.wants
 +
rm storage-gadget-init.service
 +
ln -s ../network-gadget-init.service .
  
 
=== Accessing the Beagle via the Serial Port ===
 
=== Accessing the Beagle via the Serial Port ===
Line 283: Line 371:
  
 
* See what USB/tty devices are already attached to your host
 
* See what USB/tty devices are already attached to your host
  host# '''ls /dev/ttyU*'''
+
  host$ '''ls /dev/ttyU*'''
 
* Attach a serial to USB converter to your host computer and the Beagle's serial port.
 
* Attach a serial to USB converter to your host computer and the Beagle's serial port.
 
* See what new USB/tty devices appeared
 
* See what new USB/tty devices appeared
  host# '''ls /dev/ttyU*'''
+
  host$ '''ls /dev/ttyU*'''
 
* On my host, '''/dev/ttyUSB1''' appeared. On the host computer run
 
* On my host, '''/dev/ttyUSB1''' appeared. On the host computer run
  
Line 330: Line 418:
 
have the ramdisk, I downloaded the one used being shipped with the xM  
 
have the ramdisk, I downloaded the one used being shipped with the xM  
 
boards today [http://www.google.com/url?sa=D&q=http://beagleboard-validation.s3.amazonaws.com/deploy/201008201549/sd/ramdisk.gz].  
 
boards today [http://www.google.com/url?sa=D&q=http://beagleboard-validation.s3.amazonaws.com/deploy/201008201549/sd/ramdisk.gz].  
<pre>
+
 
root@beagleboard:~# wget  
+
beagle$ '''wget http://www.google.com/url?sa=D&q=http://beagleboard-validation.s3.amazonaws.com/deploy/201008201549/sd/ramdisk.gz'''
http://www.google.com/url?sa=D&q=http://beagleboard-validation.s3.amazonaws.com/deploy/201008201549/sd/ramdisk.gz
+
Connecting to beagleboard-validation.s3.amazonaws.com (72.21.214.39:80)  
Connecting to beagleboard-validation.s3.amazonaws.com (72.21.214.39:80)  
+
ramdisk.gz          100% |*******************************| 19492k 00:00:00 ETA  
ramdisk.gz          100% |*******************************| 19492k 00:00:00 ETA  
+
beagle$ '''cp ramdisk.gz /media/mmcblk0p1/'''
root@beagleboard:~# cp ramdisk.gz /media/mmcblk0p1/  
+
beagle$ '''shutdown -r now'''
root@beagleboard:~# shutdown -r now  
+
 
</pre>
+
 
I halted the board during reboot and did:  
 
I halted the board during reboot and did:  
<pre>
+
OMAP3 beagleboard.org # mmc rescan 0  
+
OMAP3 beagleboard.org # '''mmc rescan 0'''
OMAP3 beagleboard.org # run loaduimage  
+
OMAP3 beagleboard.org # '''run loaduimage'''
Loading file "/boot/uImage" from mmc device 0:2 (xxa2)  
+
Loading file "/boot/uImage" from mmc device 0:2 (xxa2)  
3194256 bytes read  
+
3194256 bytes read  
OMAP3 beagleboard.org # run loadramdisk  
+
OMAP3 beagleboard.org # '''run loadramdisk'''
reading ramdisk.gz  
+
reading ramdisk.gz  
19960110 bytes read  
+
19960110 bytes read  
OMAP3 beagleboard.org # run ramboot  
+
OMAP3 beagleboard.org # '''run ramboot'''
</pre>
+
 
 
I allowed it to boot and did:  
 
I allowed it to boot and did:  
<pre>
+
 
root@beagleboard:~# umount /dev/mmcblk0p1  
+
beagle$ '''umount /dev/mmcblk0p1'''
root@beagleboard:~# umount /dev/mmcblk0p2  
+
beagle$ '''umount /dev/mmcblk0p2'''
root@beagleboard:~# fdisk /dev/mmcblk0  
+
beagle$ '''fdisk /dev/mmcblk0'''
Command (m for help): p  
+
Command (m for help): '''p'''
Disk /dev/mmcblk0: 3965 MB, 3965190144 bytes  
+
Disk /dev/mmcblk0: 3965 MB, 3965190144 bytes  
255 heads, 63 sectors/track, 482 cylinders  
+
255 heads, 63 sectors/track, 482 cylinders  
Units = cylinders of 16065 * 512 = 8225280 bytes  
+
Units = cylinders of 16065 * 512 = 8225280 bytes  
Sector size (logical/physical): 512 bytes / 512 bytes  
+
Sector size (logical/physical): 512 bytes / 512 bytes  
Disk identifier: 0x00000000  
+
Disk identifier: 0x00000000  
        Device Boot      Start        End      Blocks  Id  System  
+
        Device Boot      Start        End      Blocks  Id  System  
/dev/mmcblk0p1  *          1          15      120456    c  W95 FAT32 (LBA)  
+
/dev/mmcblk0p1  *          1          15      120456    c  W95 FAT32 (LBA)  
/dev/mmcblk0p2              16        444    3445942+  83  Linux  
+
/dev/mmcblk0p2              16        444    3445942+  83  Linux  
Command (m for help): d  
+
Command (m for help): '''d'''
Partition number (1-4): 2  
+
Partition number (1-4): '''2'''
Command (m for help): n  
+
Command (m for help): '''n'''
Command action  
+
Command action  
  e  extended  
+
    e  extended  
  p  primary partition (1-4)  
+
    p  primary partition (1-4)  
p  
+
'''p'''
Partition number (1-4): 2  
+
Partition number (1-4): '''2'''
First cylinder (16-482, default 16):  
+
First cylinder (16-482, default 16):
Using default value 16  
+
Last cylinder, +cylinders or +size{K,M,G} (16-482, default 482):  
+
Using default value 16  
Using default value 482  
+
Last cylinder, +cylinders or +size{K,M,G} (16-482, default 482):
Command (m for help): w  
+
The partition table has been altered!  
+
Using default value 482  
Calling ioctl() to re-read partition table.  
+
Command (m for help): '''w'''
Syncing disks.  
+
The partition table has been altered!  
root@beagleboard:~# umount /dev/mmcblk0p2  
+
Calling ioctl() to re-read partition table.  
root@beagleboard:~# resize2fs /dev/mmcblk0p2  
+
Syncing disks.  
resize2fs 1.41.9 (22-Aug-2009)  
+
beagle$ '''umount /dev/mmcblk0p2'''
Resizing the filesystem on /dev/mmcblk0p2 to 937794 (4k) blocks.  
+
beagle$ '''resize2fs /dev/mmcblk0p2'''
The filesystem on /dev/mmcblk0p2 is now 937794 blocks long.  
+
resize2fs 1.41.9 (22-Aug-2009)  
root@beagleboard:~# shutdown -r now  
+
Resizing the filesystem on /dev/mmcblk0p2 to 937794 (4k) blocks.  
</pre>
+
The filesystem on /dev/mmcblk0p2 is now 937794 blocks long.  
 +
beagle$ '''shutdown -r now'''
 +
 
 
I then waited for the reboot.  That was all there was to it.  
 
I then waited for the reboot.  That was all there was to it.  
 
Going the other way would require performing the resize operation  
 
Going the other way would require performing the resize operation  
Line 391: Line 480:
  
 
Anyone care to automate this and submit this to Angstrom?
 
Anyone care to automate this and submit this to Angstrom?
+
 
 
=== Sharing Laptop Internet Connection with BeagleBoard ===
 
=== Sharing Laptop Internet Connection with BeagleBoard ===
Two options: One uses Ubuntu's GUI network connections manager, the other requires modifying things yourself.
+
Moved to [[EBC_Exercise_02_Internet_Connection_via_the_Host]]
 
+
==== Option 1 - Using Ubuntu Network Connections GUI ====
+
 
+
# In Ubuntu, go to System -> Preferences -> Network Connections
+
# On the 'Wired' tab, select 'Auto eth0' and click 'Edit' (Note: name may be other than 'eth0'.  If nothing exists in this list, then make sure there is '''not''' an entry starting with 'auto eth0' in your /etc/network/interfaces file; such an entry prevents Network Manager from managing that interface.)
+
# Click the 'IPv4 Settings' tab and change 'Method' to 'Shared to other computers'
+
# Click apply
+
# Restart Ubuntu
+
# Connect the BeagleBoard to the laptop with the crossover Ethernet cable
+
# Boot the BeagleBoard - if Ubuntu was already running and the Ethernet cable was already plugged in, the BeagleBoard should automatically get assigned an IP address and you should be able to access the Internet on the BeagleBoard via the laptop's wireless connection
+
 
+
==== Option 2 - Modifying Things Yourself (DHCP Server) ====
+
 
+
This will setup a DHCP server on the host machine that will listen to the Ethernet port and assign an IP address to the BeagleBoard when it is connected with an Ethernet crossover cable.  The host machine will then act as a router using NAT to send packets out the wifi interface.<br />
+
A number of steps were taken from the [https://help.ubuntu.com/community/Internet/ConnectionSharing Ubuntu Community Documentation].<br />
+
Notes:
+
* 'eth0' will refer to the internal interface (connected to the BeagleBoard) and 'wlan0' will refer to the external interface (connected to the Internet).  Your interface names may differ.
+
* A number of configuration files are changed.  It's a good idea to save a backup copy of these before modifying them.
+
 
+
On the host machine, configure eth0 for a static IP:
+
<pre>sudo ifconfig eth0 192.168.1.13</pre>
+
If you don't want to configure this after every boot, add an entry to /etc/network/interfaces with the following:
+
<pre>
+
auto eth0
+
    address 192.168.1.13
+
    netmask 255.255.255.0
+
    network 192.168.1.0
+
    broadcast 192.168.1.255
+
</pre>
+
 
+
On the host machine, configure the IP tables to use NAT translation for routing packets:
+
<pre>
+
sudo iptables -A FORWARD -o wlan0 -i eth0 -s 192.168.1.0/24 -m conntrack --ctstate NEW -j ACCEPT
+
sudo iptables -A FORWARD -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
+
sudo iptables -A POSTROUTING -t nat -j MASQUERADE
+
</pre>
+
To avoid having to setup the IP tables after every boot, save the IP tables
+
<pre>sudo iptables-save | sudo tee /etc/iptables.sav</pre>
+
And add the following command to /etc/rc.local (or other appropriate file for your distribution) to be run at boot
+
<pre>iptables-restore < /etc/iptables.sav</pre>
+
 
+
IP forwarding needs to be enabled:
+
<pre>sudo sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward"</pre>
+
To make sure this is set after rebooting, add these lines to /etc/sysctl.conf:
+
<pre>
+
net.ipv4.conf.default.forwarding=1
+
net.ipv4.conf.all.forwarding=1
+
</pre>
+
 
+
Install the DHCP server software
+
<pre>sudo apt-get install dhcp3-server</pre>
+
And edit the configuration file /etc/dhcp3/dhcpd.conf (comment out any already existing lines other than "ddns-update-style none;")
+
<pre>
+
#Added for DHCP with BeagleBoard
+
default-lease-time 600;
+
max-lease-time 7200;
+
option subnet-mask 255.255.255.0;
+
option broadcast-address 192.168.1.255;
+
option routers 192.168.1.13;    #<--This must match the IP address you statically set for eth0
+
option domain-name-servers 137.112.4.196,137.112.5.28,137.112.12.11;    #<--Rose-Hulman's DNS servers (according to my laptop, at least)
+
option domain-name "rose-hulman.edu";
+
 
+
subnet 192.168.1.0 netmask 255.255.255.0 {
+
range 192.168.1.14 192.168.1.14;  #<--You can specify a larger range; I used this to force my BeagleBoard to always have the same IP so I could add an entry for that IP in /etc/hosts
+
}
+
</pre>
+
You may need to edit /etc/default/dhcp3-server to specify the interface for the DHCP server
+
<pre>INTERFACES="eth0"</pre>
+
Then restart the DHCP server service
+
<pre>sudo service dhcp3-server restart</pre>
+
 
+
You may need to reboot your host machine, and it may be necessary to run the command above to restart the DHCP server every time you boot (I'm not sure if it starts appropriately at boot).
+
 
+
Now connect the BeagleBoard to the host machine with a crossover Ethernet cable and boot the Beagle.  After booting, run 'ifconfig' to see if the Beagle was assigned an IP address.  If it does not have an IP address, try running the command 'dhclient usb0'.
+
 
+
Once the Beagle does have an IP address, try
+
<pre>ping -c 3 -W 10 www.google.com</pre>
+
to test if the setup is working correctly.  If it complains about a bad name, the DNS servers are incorrect; try pinging a specific IP such as 8.8.8.8 to see if packets get through (though unless you want to rely on all IP addresses, you will need to get some DNS servers that work).
+
 
+
==== Option 3 - Manual Routing, Static Beagle IP ====
+
 
+
This will setup the routing on Ubuntu (sending all eth0 traffic out wlan0).  It will then set a static IP address on the BeagleBoard (so you can stick an entry for your BeagleBoard in /etc/hosts for convenience).  The key difference from Option 2 is that the DHCP server in that option supplied the BeagleBoard with DNS servers.  In this option, we add a script that gives the BeagleBoard some static DNS server addresses every time it boots.
+
 
+
First, follow through the steps in Option 2 right up until it starts talking about installing the DHCP server.  Instead of installing the DHCP server, do the following.
+
 
+
On your BeagleBoard, add the following entry to <code>/etc/network/interfaces</code> (comment out any pre-existing entries regarding 'usb0')
+
<pre>
+
auto usb0
+
iface usb0 inet static
+
      address 192.168.1.14        # This is the static IP address of your choice
+
      netmask 255.255.255.0
+
      network 192.168.1.0
+
      gateway 192.168.1.13        # This must match the static IP address you assigned to eth0 on your host machine
+
</pre>
+
After booting, the BeagleBoard is now configured with a static IP address and knows the gateway for all its traffic is the address of your host machine.  The last thing to do is to make sure your BeagleBoard knows what DNS servers to use.  This information is stored in the <code>/etc/resolv.conf</code> file.  You could add it manually every time after boot, but we'll make a script to do it at boot instead.
+
 
+
On your BeagleBoard, navigate to the /etc/rc5.d/ directory.  In this directory, create a file named <code>S99<name></code> where <code><name></code> can be anything you prefer.  My file was named <code>S99SetRoseHulmanNameServers</code>.  Add the following inside that file:
+
<pre>
+
#! /bin/sh
+
echo "nameserver 137.112.4.196" >> /etc/resolv.conf      # These three IP addresses are the Rose-Hulman DNS servers
+
echo "nameserver 137.112.5.28" >> /etc/resolv.conf      # Replace them with whatever DNS servers you are using
+
echo "nameserver 137.112.12.11" >> /etc/resolv.conf
+
</pre>
+
That should be it.  Assuming all cables are connected properly and you have a WiFi connection on the host machine, after booting the BeagleBoard should have a usable Internet connection.
+
  
 
=== Using u-boot to specify a MAC address at boot ===
 
=== Using u-boot to specify a MAC address at boot ===
Line 536: Line 521:
 
I first opened the wpa_supplicant.conf file to setup my networks:
 
I first opened the wpa_supplicant.conf file to setup my networks:
  
  root@beagleboard:~# '''cd /etc'''
+
  beagle$ '''cd /etc'''
  root@beagleboard:/etc# '''gedit wpa_supplicant.conf &'''
+
  beagle$ '''gedit wpa_supplicant.conf &'''
  
 
This file is filled with numerous examples of possible wireless configurations for you to basically fill in. After looking at the examples, I scrolled down to the bottom of the page and set up two networks: one for home and one for school. Here are examples of my setup networks:
 
This file is filled with numerous examples of possible wireless configurations for you to basically fill in. After looking at the examples, I scrolled down to the bottom of the page and set up two networks: one for home and one for school. Here are examples of my setup networks:
Line 567: Line 552:
 
Now you must specify that this is the file to use for the wireless device:
 
Now you must specify that this is the file to use for the wireless device:
  
  root@beagleboard:/etc# '''cd network'''
+
  beagle$ '''cd network'''
  root@beagleboard:/etc/network# '''gedit interfaces &'''
+
  beagle$ '''gedit interfaces &'''
  
 
This file will display all of the different types of Internet connections you have setup.
 
This file will display all of the different types of Internet connections you have setup.
Line 584: Line 569:
 
Once you have finished this you can either restart the Beagle Board or:
 
Once you have finished this you can either restart the Beagle Board or:
  
  root@beagleboard:/etc/network# '''cd'''
+
  beagle$ '''cd'''
  root@beagleboard:~# '''/etc/init.d/networking restart'''
+
  beagle$ '''/etc/init.d/networking restart'''
  
 
I've found that a lot of the time the interface doesn't receive an IP address when it boots up. If you run ifconfig in the terminal you should see your wireless device connected to a network. If it is connected but no IP address I do the following:
 
I've found that a lot of the time the interface doesn't receive an IP address when it boots up. If you run ifconfig in the terminal you should see your wireless device connected to a network. If it is connected but no IP address I do the following:
  
  root@beagleboard:~# '''ifdown wlan0'''
+
  beagle$ '''ifdown wlan0'''
 
  # it will report messages here and then
 
  # it will report messages here and then
  root@beagleboard:~# '''ifup wlan0'''
+
  beagle$ '''ifup wlan0'''
 
  # more messages and it should report connecting and having an IP address
 
  # more messages and it should report connecting and having an IP address
  
Line 606: Line 591:
 
Line 564 shows an additional git repository was used.
 
Line 564 shows an additional git repository was used.
  
<pre>
+
host$ '''cd sources/openembedded'''
$ cd sources/openembedded
+
host$ '''git remote add myrepo git://gitorious.org/~Jadon/angstrom/jadon-openembedded.git'''
$ git remote add myrepo git://gitorious.org/~Jadon/angstrom/jadon-openembedded.git
+
host$ '''git remote update'''
$ git remote update
+
</pre>
+
  
 
Run this git command to get access to this repository. (It took about 2 minutes at 6:20am.) Line 21 shows the hash tag for the build.
 
Run this git command to get access to this repository. (It took about 2 minutes at 6:20am.) Line 21 shows the hash tag for the build.
  
<pre>
+
ANGSTROM_REPO_ID=24805033b1205acc35f8b4d75cc42f8b9c2a1b38
ANGSTROM_REPO_ID=24805033b1205acc35f8b4d75cc42f8b9c2a1b38
+
</pre>
+
  
 
If we pull from this tag we will have the same files as were used to generate the SD image.  So do the following
 
If we pull from this tag we will have the same files as were used to generate the SD image.  So do the following
  
<pre>
+
host$ '''git checkout 24805033b1205acc35f8b4d75cc42f8b9c2a1b38'''
$ git checkout 24805033b1205acc35f8b4d75cc42f8b9c2a1b38
+
 
</pre>
+
 
This takes about 10 seconds.
 
This takes about 10 seconds.
  

Revision as of 15:30, 12 September 2013

thumb‎ Embedded Linux Class by Mark A. Yoder


Some useful tips and tricks for Linux and the Beagleboard.

Interesting Links

Since we are working with the open source community, you need to know where the action is. Here are some useful links to what's happening in the Beagle community.

Linux

Learn UNIX in 10 Minutes is a quick overview of the most commonly used Linux commands.

Top 10 Tools is a nice summary of 10 of the most useful Linux commands.

Quick Tips

Tip Description
beagle$ gnome-open
Open a file or directory using the default program
Give the IP address a name Inside /etc/hosts add a line of the form <IP address> <alias> this will allow you to refer to the host by name.
Built-in GUI for gdb If you invoke gdb with the command line argument -tui, it will show a built-in GUI
beagle$ ntpdate ntp.org
beagle$ rm /etc/localtime
beagle$ ln -s /usr/share/zoneinfo/America/New_York /etc/localtime
This will go to a network time protocol server and get the current time and set the Beagle to it and set the local time zone. [1]
beagle$ mount -t debugfs debugfs /sys/kernel/debug/
beagle$ cd /sys/kernel/debug
beagle$ ls
Kernel Debug Info

Connecting to RHIT wifi

There is a discussion in the Beagle Google Group about getting wireless working with the bone.

Use these settings for connecting to the Rose-Hulman wireless network:

  • SSID: RHIT-1X
  • Security: WPA & WPA2 Enterprise
  • Leave "anonymous identity" blank
  • CA Certificate: (None)
  • PEAP version: Version 0
  • Inner authentication: MSCHAPv2
  • Use your Rose username and password

bash

Tip Description
Ctrl-r Reverse incremental search
Ctrl-g Abort command
Esc-. Insert last argument from last command

ssh

Suspending ssh

Most programs can be suspended by typing ^z (Ctrl-z). If you have an ssh connection to another machine you can suspend it by entering ~^z. You can resume the connection by entering fg.

ssh and X-windows

When using ssh between to X-windows systems try

host$ ssh -CX root@beagle

The -X set the DISPLAY variable on the remote machine so you can open windows from the beagle on your host machine.

The -C compressed the data over the link. Good for slow connections.

vnc

You can run a vnc server on the Beagle. Install it with:

beagle$ opkg update
beagle$ opkg install x11vnc

Install a password with

beagle$ x11vnc -storepasswd

Run it on the Beagle with

beagle$ x11vnc -display :0 -ssl -usepw -forever -q &

On your host, connect to it with:

host$ vinagre

or Applications:Internet:Remote Desktop Viewer

Authorizing ssh

ssh and scp can be set up for automatic authorization so you don't have to enter your password when using these commands. Here's how to do it. First let's see what's already there:

  • On your Beagle run
beagle$ ls ~/.ssh

~/.ssh may not exist, if not, it will be created. If it's there, check the files in it.

  • On your host computer run
host$ ssh-copy-id root@beagle

It was ask for you beagle password and then copy the needed files to it.

  • Back on the beagle to see what has changed:
host$ ssh -CX root@beagle
beagle$ ls ~/.ssh

The ssh command shouldn't ask for a password. What new files appeared?

ssh configuration

Here's a nice tip so you don't have to remember who to login as on the beagle. On your host, put the following in ~/.ssh/config.

Host beagle
   User root
   UserKnownHostsFile /dev/null
   StrictHostKeyChecking no

Before you had to

host$ ssh -CX root@beagle

Now you can just

host$ ssh -CX beagle

Mounting dfs/afs

You can set up your Linux box to directly mount your afs and dfs files. The Rose-Hulman Linux Users' Group has a nice page with the details .

After installing sshfs I added the following to my /etc/fstab file:

sshfs#username@dfs.Rose-hulman.edu:/DFS/MyDocs/username /home/username/MyDocs fuse user,noauto,uid=1000,gid=1000 0 0
sshfs#username@dfs.rose-hulman.edu:/DFS/Users/Y/username /home/username/dfs-home fuse user,noauto,uid=1000,gid=1000 0 0
sshfs#username@afs.rose-hulman.edu: /home/username/afs-home fuse user,noauto,uid=1000,gid=1000 0 0

You'll have to replace username with your login name. Then create the mount points:

host$ cd ~
host$ mkdir MyDocs
host$ mkdir dfs-home
host$ mkdir afs-home

Now you can mount your files by using:

host$ cd ~
host$ mount dfs-home
host$ cd dfs-home
host$ ls

You should now see your dfs files. You can unmount using:

host$ cd ~
host$ sudo umount dfs-home

debugfs

debugfs looks like a handy way to look into the kernel. These notes are based on the example here.

beagle$ cd /
beagle$ mkdir debugfs
beagle$ mount -t debugfs none debugfs

Then explore...

bone$ cd debugfs; ls -F
asoc/   gpio       mmc0/      pm_debug/   sched_features  vram
bdi/    hid/       musb/      regdump     testmode        wakeup_sources
clock/  memblock/  omap_mux/  regulator/  usb/
beagle$  cd debugfs; ls -F
asoc/  clock/  hid/   omapdss/   sched_features  usb/
bdi/   gpio    mmc0/  pm_debug/  tracing/        vram

Tool chain work flows

Here is a link to a list of workflows for various tool chains.

Installing more applications

On the Beagle

On the Beagle under Angstrom you use opkg to manage packages. Start with

beagle$ opkg update

This updated the local database with the current version information. Then

beagle$ opkg list > /tmp/list
beagle$ less /tmp/list

will list all the available packages. You can also search here [1] to see what packages are available.

[1] www.angstrom-distribution.org/repo/

On the host

There are tree command that I use for managing packages.

dpkg
is used for listing what packages are installed.
synaptic
is a GUI-based package manager. I used it to discover new packages to install.
apt-get
is used to install and update packages.

For example, let's suppose you run make menuconfig and the error message says

 *** Install ncurses (ncurses-devel) and try again.

Let's see what's installed.

host$ dpkg -l > /tmp/list
host$ grep curses /tmp/list
ii  libncurses5      5.7+20090803-2ubuntu3  shared  libraries for terminal handling
ii  libncursesw5     5.7+20090803-2ubuntu3  shared libraries for terminal handling (wide
ii  mtr-tiny         0.75-2build1           Full screen ncurses traceroute tool
ii  ncurses-base     5.7+20090803-2ubuntu3  basic terminal type definitions
ii  ncurses-bin      5.7+20090803-2ubuntu3  terminal-related programs and man pages

Hmmm... there's something related to ncurses installed, but the error says something about ncurses-devel. Let's fire up synaptic

host$ synaptic &

Enter ncurses-devel in the search field. Screenshot-Synaptic Package Manager .png

The green dot in the S column says the package is installed. libncurses5-dev isn't installed. Install it with:

host$ sudo apt-get install libncurses5-dev

And now your make should work.

byobu - A Screen Manager

For years Unix has had screen which is a screen manager. byobu is wrapper for screen that puts a nice face on it. You can run byobu on your host computer and on the Beagle. With byobu you can start a long running program (bitbake for example) in one terminal and detach from the terminal and the program will keeping running in the background. Using byobu you can later attach to the program (possibly from another terminal) and see how the program is progressing.

Install byobu on your host with:

host$ sudo apt-get update
host$ sudo apt-get install byobu

It's a bit harder on the Beagle.

beagle$ opkg update
beagle$ opkg install screen

Go to here and download the latest version to your Beagle.

beagle$ tar zxvf byobu_*.orig.tar.gz 
beagle$ cd byobu* and follow the instructions in INSTALL. I had to hack one file.
beagle$ gedit /usr/local/lib/byobu/.constants.  

Change the last two lines to:

# command -v gsed >/dev/null && export SED="gsed" || export SED="sed"
# command -v greadlink >/dev/null && export READLINK="greadlink" || export READLINK="readlink"
export SED="sed"
export READLINK="readlink"

Now you can run it.

beagle$ byobu

You'll see a command prompt. You'll also see some status information on the bottom two lines. Type Ctrl-A ? for help. Type Ctrl-A Ctrl-D to detach from the session. Running byobu again will reattach you to the session. Try running byobu in two windows at the same time. You should see the same session in both.

Hmmm.... I had to reinstall and it doesn't seem to be working now.

Finding what opkg installed

Once you've run opkg, how do you know what's been installed? Take a look in /var/lib/opkg/info or /usr/lib/opkg/info. The files that end in .list contain a list of what's been installed.

Backing up an SD card with dd

Here's the command I use to backup an SD card. I use System:Administration:Disk Utility to figure out the path to the card. In this case it's /dev/sdc

host$ sudo time dd if=/dev/sdc of=FIE2011.img bs=4M count=1000
host$ sudo chown yoder:yoder FIE2011.img
host$ md5sum FIE2011.img > FIE2011.img.md5
host$ bzip2 -k FIE2011.img

It takes about 5 minutes to dd a 4G card, 1.2 minutes for md5 and bzip2 takes about 23 minutes.

It looks like the 7z compression is becoming popular. Use it via

host$  7za a FIE2011.img.7z IFE2011.img

It took 16 minutes. The file size is 454M compared to 628M. Wow, faster and smaller.

CSSE's Linux reference page

CSSE332, Operating Systems, has a nice page of Linux resources.

Local Ubuntu Update Mirror

Darryl Mouck in CSSE has passed this on...

We host a local mirror for all ubuntu updates. This is from the current distro back to hardy; it hosts every distro that ubuntu currently supports.

In order to get your system to point to our mirror, please copy and paste this rather lengthy command into a terminal:

host$ sudo cp /etc/apt/sources.list{,.old} && \
    sudo sh -c '\
. /etc/lsb-release &&
echo "
deb http://ftp.csse.rose-hulman.edu/ubuntu $DISTRIB_CODENAME main restricted universe multiverse
deb http://ftp.csse.rose-hulman.edu/ubuntu $DISTRIB_CODENAME-updates main restricted universe multiverse
deb http://ftp.csse.rose-hulman.edu/ubuntu $DISTRIB_CODENAME-security main restricted universe multiverse
" > /etc/apt/sources.list' && sudo apt-get update

The text and further instructions are available here.

The script makes a backup of the updates file and replaces it with links to our mirror. The $DISTRIB_CODENAME is replaced by whatever distro you are running (eg. lucid, maverick, natty etc.). I wish I could take credit for it, but it was a joint effort with Mike McLeish :-)

Using pico DLP with BBB

Put this in uEnv.txt to use the BBB with a pico DLP.

optargs=video=HDMI-A-1:640x480@60

More tips

GigaMegaBlog has some nice tips for the BeagleBone, many of which apply to the -xM.

Windows

Most of the work is done under Linux; however there are some handy Windows-based tools.

Serial Port

SecureCRT is a good program that gives you both access to a serial port and is also an ssh client. Rose has a license for SecureCRT.

Tera Term also gives you access to the serial port and it's free.

Notepad++

Notepad++ is a nice text editor for Windows.

Set up on the BeagleBoard

Setup stuff on github

If you've cloned the course github site ([EBC Exercise 05 Getting Exercise Support Materials]]) you will find set up things in exercises/setup. install.sh is a list of various things I to to a fresh SD card to 'move in'. For example, the bone will mount a filesystem on the host computer if it's connected via USB. You can turn this off and have the eithernet over USB run at boot time with:

# Turn off storage gadget, turn on network at boot time.
cd /lib/systemd/system/basic.target.wants
rm storage-gadget-init.service
ln -s ../network-gadget-init.service .

Accessing the Beagle via the Serial Port

During boot up the Beagle logs various messages on the serial port. You can see these messages by:

  • See what USB/tty devices are already attached to your host
host$ ls /dev/ttyU*
  • Attach a serial to USB converter to your host computer and the Beagle's serial port.
  • See what new USB/tty devices appeared
host$ ls /dev/ttyU*
  • On my host, /dev/ttyUSB1 appeared. On the host computer run
host$ byobu /dev/ttyUSB1 115200

where ttyUSB1 is what appeared when you plugged in your converter.

You are now talking to your Beagle's serial port. Login quickly. There appears to be a bug that makes garbage appear on your screen if you wait too long. Try

beagle$ shutdown -r now

You will see the shutdown messages, followed by the U-boot messages. After a 3 second (or so) delay you will see the kernel booting.

Tip 1: Ctrl-a H will cause the data on the serial port to be logged. See

host$ man byobu

for help.

Tip 2: <F6> will disconnect from the session. You can reconnect later.

Installing Ubuntu

I've installed 2 different versions of Ubuntu on my SD cards. Each of my SD cards is 4GB, and this is just large enough to hold the Ubuntu images.

I followed the instructions from here and here.

The first link references a Ubuntu wiki which details how to install a netbook edition of Ubuntu on ARM/OMAP processor-based systems. It is not beagle-specific. This image runs a little slowly, but not much slower than the SPEd image.

The second link references instructions for installing another image. This image is very minimal, and doesn't have a gui. There are instructions for installing a gui, which I did, with good success. As far as I can tell, even with the gui, this is the fastest image so far.

Installing Always Innovating's Super Jumbo

Always Innovating works with branded products and services companies that are looking to deliver great touch devices as part of their offerings. They have published a free SD card image for the BeagleBoard that runs Angstrom, Android, Ubuntu, and ChromiumOS. Here's a video showing what it can do.

I've put a copy of the compressed image on my DFS site. Feal free to play with it. Here's a wiki that shows how to switch between OS's on the fly.

Resizing an SD card partition via the Beagle

The following is a slick way to boot the Beagle so it isn't using the SD, then repartition the SD card. It came from [2]

Jason Kridner says ... I got a related question from Mark about how to perform the partition resizing, so I figured I'd address that here. I don't believe you'd be able to resize a mounted partition and that this operation would require another file system to mount. Because this image does not have the ramdisk, I downloaded the one used being shipped with the xM boards today [3].

beagle$ wget http://www.google.com/url?sa=D&q=http://beagleboard-validation.s3.amazonaws.com/deploy/201008201549/sd/ramdisk.gz
Connecting to beagleboard-validation.s3.amazonaws.com (72.21.214.39:80) 
ramdisk.gz           100% |*******************************| 19492k 00:00:00 ETA 
beagle$ cp ramdisk.gz /media/mmcblk0p1/ 
beagle$ shutdown -r now 

I halted the board during reboot and did:

OMAP3 beagleboard.org # mmc rescan 0 
OMAP3 beagleboard.org # run loaduimage 
Loading file "/boot/uImage" from mmc device 0:2 (xxa2) 
3194256 bytes read 
OMAP3 beagleboard.org # run loadramdisk 
reading ramdisk.gz 
19960110 bytes read 
OMAP3 beagleboard.org # run ramboot 

I allowed it to boot and did:

beagle$ umount /dev/mmcblk0p1
beagle$ umount /dev/mmcblk0p2
beagle$ fdisk /dev/mmcblk0
Command (m for help): p 
Disk /dev/mmcblk0: 3965 MB, 3965190144 bytes 
255 heads, 63 sectors/track, 482 cylinders 
Units = cylinders of 16065 * 512 = 8225280 bytes 
Sector size (logical/physical): 512 bytes / 512 bytes 
Disk identifier: 0x00000000 
        Device Boot      Start         End      Blocks   Id  System 
/dev/mmcblk0p1   *           1          15      120456    c  W95 FAT32 (LBA) 
/dev/mmcblk0p2              16         444     3445942+  83  Linux 
Command (m for help): d 
Partition number (1-4): 2 
Command (m for help): n 
Command action 
   e   extended 
   p   primary partition (1-4) 
p 
Partition number (1-4): 2 
First cylinder (16-482, default 16):

Using default value 16 
Last cylinder, +cylinders or +size{K,M,G} (16-482, default 482):

Using default value 482 
Command (m for help): w 
The partition table has been altered! 
Calling ioctl() to re-read partition table. 
Syncing disks. 
beagle$ umount /dev/mmcblk0p2 
beagle$ resize2fs /dev/mmcblk0p2 
resize2fs 1.41.9 (22-Aug-2009) 
Resizing the filesystem on /dev/mmcblk0p2 to 937794 (4k) blocks. 
The filesystem on /dev/mmcblk0p2 is now 937794 blocks long. 
beagle$ shutdown -r now 

I then waited for the reboot. That was all there was to it. Going the other way would require performing the resize operation first and specifying the size.

Anyone care to automate this and submit this to Angstrom?

Sharing Laptop Internet Connection with BeagleBoard

Moved to EBC_Exercise_02_Internet_Connection_via_the_Host

Using u-boot to specify a MAC address at boot

The BeagleBoard has a problem where Linux will randomly select a MAC address at boot. In order to get around this, one blogger provides a patch to enable a kernel command line parameter to set a MAC address. Below is one way to apply, your mileage may vary.

  1. Make sure your kernel compiles and boots.
  2. Grab the patch, and open it with gedit
  3. Open .../git/drivers/net/usb/smsc95xx.c
  4. Go to line 64-ish, and look for a place to insert the first code with plus signs preceding each line. Remove the plus signs.
  5. Go to 656-ish, and repeat for the other block of code.
  6. Save and re-compile.
  7. Install the new kernel as normal.
  8. Edit the kernel command line. There are two ways to do this:
    1. Edit the uBoot source and recompile
      1. Go to u-boot, and edit ../include/configs/omap3_beagle.h
      2. Change mmcargs, nandargs, and ramargs to include a parameter for "ethaddr=...", where ... is your MAC address.
      3. Save, close, recompile.
      4. Install the new u-boot as normal.
    2. Edit the boot.scr file
      1. See Modifying Kernel Command Line Parameters
  9. Register your MAC Address via any method that works, and enjoy reduced-hassle internet access on your Beagle.
  10. Optionally, Update opkg.

Rename an External Storage Device

I ran out of space on my Linux (Ubuntu) partition, so I opted to do all my development on an external hard drive. This works just fine, except that the drive is labeled "Expansion Drive" and the space in there causes problems in some of the setup scripts. It is possible to add an entry in /etc/fstab that mounts the device with a certain name, but this is very cumbersome, for many reasons. Instead, I used this [1] very helpful guide to change the label on my external drive.

[1] help.ubuntu.com/community/RenameUSBDrive


Setup a USB Wireless Device on Beagle

(Here are instructions on setting up a Belkin USB dongle.)

The device I used to setup a wireless connection on the Beagle Board was the Linksys Compact Wireless-G USB Network Adapter with SpeedBooster.

I first opened the wpa_supplicant.conf file to setup my networks:

beagle$ cd /etc
beagle$ gedit wpa_supplicant.conf &

This file is filled with numerous examples of possible wireless configurations for you to basically fill in. After looking at the examples, I scrolled down to the bottom of the page and set up two networks: one for home and one for school. Here are examples of my setup networks:

#Home Network
network={
        ssid="YourHomeNetworkName"
        psk="YourHomeNetworkPassword"
}

#School Network
network={
        ssid="RHIT-1X"
        proto=WPA
        key_mgmt=WPA-EAP
        pairwise=CCMP
        group=TKIP
        eap=PEAP
        phase1="peapver=0 peaplabel=0"
        phase2="auth=MSCHAPV2"
        scan_ssid=1
        identity="YourSchoolUsername"
        password="YourSchoolPassword"
}

For the network examples above,the quotation marks actually belong there but replace the Your.... areas with your corresponding information. No <space> before the first quotation mark.When finished editing save and exit this file. The information for the RHIT school network was found here:RHLUG

Now you must specify that this is the file to use for the wireless device:

beagle$ cd network
beagle$ gedit interfaces &

This file will display all of the different types of Internet connections you have setup. To use the wpa_supplicant.conf file, scroll down to around line 42 of the code and uncomment the configuration for wpasupplicant. After doing this make sure all of the above lines mentioning anything about wlan0 are commented out. Return back to where it says "iface wlan0 inet dhcp" that you uncommented around line 42. Add "auto wlan0" above this line, make sure the line "wpa-conf /etc/wpa_supplicant.conf" is uncommented below the iface line, and change the wpa-driver line below that line to wext. So after all of that the code in this file for the wireless device should be the following:

auto wlan0 
  iface wlan0 inet dhcp
     wpa-conf /etc/wpa_supplicant.conf
     wpa-driver wext

NOTE: the auto wlan0 command in this file means that this device will load at boot time. You can take the time in here now to comment out any interfaces you don't use like auto usb0 to make these devices not load at boot time, which will increase the speed at which you boot up. Save and exit this file

Once you have finished this you can either restart the Beagle Board or:

beagle$ cd
beagle$ /etc/init.d/networking restart

I've found that a lot of the time the interface doesn't receive an IP address when it boots up. If you run ifconfig in the terminal you should see your wireless device connected to a network. If it is connected but no IP address I do the following:

beagle$ ifdown wlan0
# it will report messages here and then
beagle$ ifup wlan0
# more messages and it should report connecting and having an IP address

This ifdown ifup method has worked every time for me so far but if anyone can find a way to prevent having to do this almost every time please feel free to edit this

Development tips for bitbake and oe

Gumstix Development Tips appears to have some good ideas that can apply to the Beagle too.

Point to a given git snapshot

The original SD card image came from here. The file ec2buld.sh shows how the image was build. There are a couple of interesting things in this file.

Line 564 shows an additional git repository was used.

host$ cd sources/openembedded
host$ git remote add myrepo git://gitorious.org/~Jadon/angstrom/jadon-openembedded.git
host$ git remote update

Run this git command to get access to this repository. (It took about 2 minutes at 6:20am.) Line 21 shows the hash tag for the build.

ANGSTROM_REPO_ID=24805033b1205acc35f8b4d75cc42f8b9c2a1b38

If we pull from this tag we will have the same files as were used to generate the SD image. So do the following

host$ git checkout 24805033b1205acc35f8b4d75cc42f8b9c2a1b38

This takes about 10 seconds.

Fixing Problems

Kernel Boot Problems

Here is a link with some suggestions of what to do if your kernel isn't booting properly.

Serial port garbage

If you are having trouble with garbage on the console, this might help. Sometimes the serial port times out. Most of the time it just generates some junk which can be cleared with CTRL-U or backspace. However, if it happens at the login prompt then getty thinks the terminal is 7-bit with parity (rather than 8-bit raw). If this happens and you continue to login the whole session appears to be scrambled - if you press CTRL-D you can login again provided you don't stop typing... :] I have simply added the following two lines to root's .profile:

stty -parenb -parodd cs8 -inpck -istrip 
echo 0 > /sys/class/tty/ttyS2/device/sleep_timeout

A better fix would probably be to just add the second line to a rc.d startup script somewhere.

This suggestion came from this posting.

Turning off gpe

The following worked last year, but doesn't seem to work now.

Running above will write on top of what Angstrom is doing. You can turn off the display manager by using:

/etc/init.d/gpe-dm stop

Replace stop with start if you want to run it again.

Details of making your own MLO

Hardware Environment for a BeagleBoard XM with JTAG

Software Environment for a BeagleBoard XM with JTAG

This might make a good lab.

Getting help from a news group

Here's a nice tip on what to do before posting a question to a news group.




thumb‎ Embedded Linux Class by Mark A. Yoder