Re: [beagleboard] Newbie question regarding Xenomai and BeagleBone

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meino....@gmx.de

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Oct 5, 2012, 10:29:52 AM10/5/12
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Stefan <videv...@gmail.com> [12-10-05 16:11]:
> Hello! :)
>
> I am quite new to the whole embedded Linux world and am struggling a bit
> with the concept of patching the kernel on my BeagleBone to enable Xenomai
> functionality.
>
> Am I right in assuming that these are the steps to achieve this:
>
> 1) Check out relevant kernel source files
> 2) Check out the relevant OMAP patches (where are those and how do you
> apply them, or are there source files for the patched kernel that properly
> supports the processor on the beaglebone?)
> 3) Check out the Xenomai sources, and configure the kernel through the
> Xenomai make files
> 4) Compile the kernel?
>
> Is there anything specific to look out for except for some of the
> particular CFLAGS for the OMAP3?
>
> What I am really uncertain of is what do you do once all of this is done?
> Do you overwrite whatever is on the beaglebone or?
>
> What would be great is some sort of a more or less step by step process of
> how to do this.
>
> Thanks a lot! Thought I'd ask before I delve into breaking the Angstrom
> distribution on my bone.
>
> Stefan
>
> P.S. I've read the documentation on the Xenomai page and the one on the
> elinux wiki regarding kernel patching and compilation but am still quite
> confused. I guess this is an easy general question for any linux expert,
> it's just that I have no experience building kernels etc.
>
> --
>
>

Hi Stefan,

dont know anything about the way Xenomai may be integrated into the
kernel...but the general way to a homebrewed kernel is as follows:

First, before doing anything else is to backup the SD card which have
come with your beaglebone. If anything goes wrong, you can save it
back to the SD card and nothing bad has happened. Use dd for backup
the SD card.

(do it right now.... :) )

Look for Robert Nelsons kernel sources, retrieve the sources via git
and built a kernel based on the default config, which come with
the sources.
Follow the instructions here:
http://www.eewiki.net/display/linuxonarm/BeagleBone
(Look for "Linux Kernel". Read the README, which will be downloaded).

Install the kernel on the SD-card as described. Connect your
beaglebone via USBserial with you LINUX-PC and watch the kernel
booting.

If necessary, modify the kernel config and use tools/rebuild.sh
to rebuild the kernel. Try it again.

If your kernel works fine, make a backup of the kernel source tree
(complete) and ... <fill in the Xenomai stuff here>.

I think you will also have to modify the userland for that.

In my opinion, Gentoo is easier to handle and better (more recent)
documented as the Angstrom Distribution, while the Angstrom
Distribution comes with all bells and whistles regarding the kernel
features (SGX for example). Also in my opnion Gentoo has a more
complete userland.
Gentoo for Beaglebone is described here:
http://dev.gentoo.org/~armin76/arm/beaglebone/install.xml

There also other distributions for the Beagles available.

But these are only my two cent and your mailage may vary...

HTH!

Best regards,
mcc





Stefan

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Oct 8, 2012, 10:50:12 AM10/8/12
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Hi mcc!

Thanks for taking the time to point me in the right direction. I will go ahead and try what you've suggested.

Quick question regarding Gentoo -- does it support the LAN over USB out of the box? If it does not it would not really be great, as right now this is the most convenient way for me to interface with the Beaglebone.

Will let you know how my attempts at compiling the kernel go!

Kind Regards,
Stefan

Siji Sunny

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Oct 8, 2012, 12:19:22 PM10/8/12
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Hi mcc!

Thanks for taking the time to point me in the right direction. I will go ahead and try what you've suggested.

Quick question regarding Gentoo -- does it support the LAN over USB out of the box? If it does not it would not really be great, as right now this is the most convenient way for me to interface with the Beaglebone.

Dear Stefan,

I have found documentation on xenomai website regarding the arm port.

http://www.xenomai.org/index.php/I-pipe-core:ArmPorting

Hope this will help you to build it.


Will let you know how my attempts at compiling the kernel go!

Kind Regards,
Stefan

--
 
 



--
Siji Sunny


meino....@gmx.de

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Oct 8, 2012, 1:06:33 PM10/8/12
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Stefan <videv...@gmail.com> [12-10-08 18:16]:
>
>
> On Friday, October 5, 2012 3:30:52 PM UTC+1, Meino....@gmx.de wrote:
> >
> > Stefan <videv...@gmail.com <javascript:>> [12-10-05 16:11]:
> --
>
>

Hi Stefan,

The userland (Gentoo) is not responsible for this features -- it is
handled by the kernel.

The best things you can do (I think...;) ) is to boot an image, from
which you know, that it supports this feature. With a little luck (the
kernel of this image needs to support the following feature) the
config file for building the kernel was included in the kernel and
can be accessed by (as root):

cat /proc/config.gz > <a place of the SD card or on a USBStick>

This way you will get a valid config, which can be used as a base
and "cheat table" for configuring Robert Nelsons kernel (which also
comes with a nice default config...!).

Furthermore this may of interest for you:
http://elinux.org/BeagleBone (look for "Ethernet-over-USB")
and
http://www.linux-usb.org/usbnet/ (for a more general information).

HTH!

Good Luck!
Best regards,
mcc






Stefan

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Oct 10, 2012, 11:51:03 AM10/10/12
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Just a quick update -- I was just able to compile a vanilla kernel for the beaglebone -- will test it tomorrow, and hopefully try to patch it with xenomai.

Will likely update when I run into trouble (which I likely will).

-- Stefan
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Stefan Videv

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Jan 16, 2013, 11:45:08 AM1/16/13
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On 1/16/2013 4:15 PM, yogi.an...@gmail.com wrote:
Stefan -

Did you get the bone patched with Xenomai?
Yes but running a v2.3 of the Linux kernel.

-- Stefan
--
For more options, visit http://beagleboard.org/discuss
 
 

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Stefan Videv

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Jan 17, 2013, 5:29:33 AM1/17/13
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On 1/16/2013 5:14 PM, Yogi Patel wrote:
Do you have instructions anywhere? I'm seeing some problems with the latency test.
Not really. What kind of problems?

I think your best port of call would be the xenomai mailing list (xen...@xenomai.org). People are very active there and chances are they'll have the answers.

-- Stefan

Gopal

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Jan 17, 2013, 10:14:30 PM1/17/13
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Following is a good link for applying xenomai patch for beagleboard. Similar instructions may be followed for beaglebone.


In this link actually, it desribes even botting kernel over NFS. That may be ignored if not desired at the moment.
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