Embedded Linux with Xenomai support

Embedded Linux with Xenomai support

[Asier]

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Hello all,

I've just started studying the Yocto project, so I beg your pardon if this
question has been already solved or it's just too easy (RT*M).

I've got a working embedded system running Xenomai v2.5.5. The user
interface has been developed with Qt Embedded. The kernel has been compiled
using the ELinOS Embedded Linux distribution.

Now, I want to change that interface to X11 so that I can use a desktop
manager as well as some other X11 applications. The ELinOS distribution has
an XServer, but it lacks a way of easily adding any desktop manager. Thus,
I’m thinking about using another Linux distribution.

That is how I have found the Yocto project. I think this can be the best
solution for my new system.

Is there any Linux distribution based on the Yocto project that lets me
configure my embedded kernel with Xenomai? If not, has anybody got any
experinece in adding Xenomai to the Yocto project?

I'm using an Atom N270 chipset.

Thanks in advance, best regards,

Asier

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Re: Embedded Linux with Xenomai support

[Darren Hart]

Hi Asier,

On Fri, 2013-08-30 at 12:34 +0200, Asier wrote:
> Hello all,
> 
> 
> I've just started studying the Yocto project, so I beg your pardon if
> this question has been already solved or it's just too easy (RT*M).
> 
> 
> I've got a working embedded system running Xenomai v2.5.5. The user
> interface has been developed with Qt Embedded. The kernel has been
> compiled using the ELinOS Embedded Linux distribution.
> 
> Now, I want to change that interface to X11 so that I can use a
> desktop manager as well as some other X11 applications. The ELinOS
> distribution has an XServer, but it lacks a way of easily adding any
> desktop manager. Thus, I’m thinking about using another Linux
> distribution.
> 
> 
> That is how I have found the Yocto project. I think this can be the
> best solution for my new system.
> 
> 
> Is there any Linux distribution based on the Yocto project that lets
> me configure my embedded kernel with Xenomai? If not, has anybody got
> any experinece in adding Xenomai to the Yocto project? 

I am not aware of anyone using Xenomai with Yocto to date (although that
doesn't mean nobody is). Our Real-Time focus has been on the PREEMPT_RT
Linux kernel, which we do have recipes for.

It appears as though Xenomai has changed quite a bit over the years. If
my quick re-reading of their material is correct, the Xenomai core is
implemented as a Linux kernel module which can built in to a standard
Linux kernel?

If that is the case, consider having a look at the hello-mod example for
a recipe building an out of tree kernel module. Then have a look at the
Yocto project Linux kernel development manual:

http://www.yoctoproject.org/docs/1.4/kernel-dev/kernel-dev.html

Out of curiosity, what sort of real-time requirements do you have?

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel

Re: Embedded Linux with Xenomai support

[Robert Berger]

Hi,

On 08/30/2013 07:56 PM, Darren Hart wrote:

>> Is there any Linux distribution based on the Yocto project that lets
>> me configure my embedded kernel with Xenomai? If not, has anybody got
>> any experinece in adding Xenomai to the Yocto project? 
> 
> I am not aware of anyone using Xenomai with Yocto to date (although that
> doesn't mean nobody is). Our Real-Time focus has been on the PREEMPT_RT
> Linux kernel, which we do have recipes for.

googling for meta-xenomai reveals:

[1][2]

> 
> It appears as though Xenomai has changed quite a bit over the years. If
> my quick re-reading of their material is correct, the Xenomai core is
> implemented as a Linux kernel module which can built in to a standard
> Linux kernel?

... kind of ...

kernel space:

You need to apply a patch to a certain kernel version and configure the
kernel afterwards.

So for an ARM architecture there is a patch for the 3.8 kernel[3]

user land:

But unlike with preempt-rt you also need to build the Xenomai userland
stuff.

> 
> Out of curiosity, what sort of real-time requirements do you have?
> 

That's a good point. Shameless self promotion [4].

Regards,

Robert

[1] https://github.com/nojgosu/meta-xenomai
[2] https://github.com/DrunkenInfant/beaglebone-xenomai
[3]
http://git.xenomai.org/?p=xenomai-head.git;a=tree;f=ksrc/arch/arm/patches;h=c6045f00819318970d6bba65c397609052c9414e;hb=HEAD
[4] http://www.reliableembeddedsystems.com/pdfs/2010_03_04_rt_linux.pdf


..."A language that doesn't affect the way you think about programming
is not worth knowing." - Anonymous

My public pgp key is available,at:
http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x90320BF1

Re: Embedded Linux with Xenomai support

[Wolfgang Denk]

Dear Asier,

In message <CAMZj-5MD+kLf3JVS7Mmyq-JfREKPdcoam0NFCTrqsFw4bnrx4A@mail.gmail.com> you wrote:
>
> Is there any Linux distribution based on the Yocto project that lets me
> configure my embedded kernel with Xenomai? If not, has anybody got any
> experinece in adding Xenomai to the Yocto project?

ELDK adds full Xenomai support starting with release v5.4 ; please see
www.denx.de/wiki/view/ELDK-5 for details, or feel free to ask for more
details on the ELDK mailing list, see
http://lists.denx.de/mailman/listinfo/eldk

> I'm using an Atom N270 chipset.

ELDK primarily supports ARM, MIPS and Power architectures.  We didn't
test the Xenomai stuff on x86 yet.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de
Real programmers don't comment their code. It was hard to  write,  it
should be hard to understand.

Re: Embedded Linux with Xenomai support

[Asier]

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Thank you for all your answers.

As Robert Berger wrote, Xenomai is a patch that you need to apply to the
kernel and then compile it. I haven't done it yet, but I think there might
be some difficulty if patching an already patched kernel. Is this the case
in the Yocto distributions?

Building the userland stuff may also be quite ardous.

> Out of curiosity, what sort of real-time requirements do you have?
>
I want hard real-time. Really, it might be enough with soft real-time, but
I don't want to take the risk. The real-time system has a 1ms period.


> ELDK adds full Xenomai support starting with release v5.4 (...)
> ELDK primarily supports ARM, MIPS and Power architectures.  We didn't
> test the Xenomai stuff on x86 yet.
>
Wolfgang, do you plan to support x86 architecture?

I'll ask Denx, as well as Wind River and Enea about Xenomai and x86 support
for their Linux distributions. If I get through something, I'll let you
know.

Best regards,

Asier



2013/9/2 Wolfgang Denk <wd@denx.de>

> Dear Asier,
>
> In message <
> CAMZj-5MD+kLf3JVS7Mmyq-JfREKPdcoam0NFCTrqsFw4bnrx4A@mail.gmail.com> you
> wrote:
> >
> > Is there any Linux distribution based on the Yocto project that lets me
> > configure my embedded kernel with Xenomai? If not, has anybody got any
> > experinece in adding Xenomai to the Yocto project?
>
> ELDK adds full Xenomai support starting with release v5.4 ; please see
> www.denx.de/wiki/view/ELDK-5 for details, or feel free to ask for more
> details on the ELDK mailing list, see
> http://lists.denx.de/mailman/listinfo/eldk
>
> > I'm using an Atom N270 chipset.
>
> ELDK primarily supports ARM, MIPS and Power architectures.  We didn't
> test the Xenomai stuff on x86 yet.
>
> Best regards,
>
> Wolfgang Denk
>
> --
> DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de
> Real programmers don't comment their code. It was hard to  write,  it
> should be hard to understand.
>

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Re: Embedded Linux with Xenomai support

[Christian Gagneraud]

On 02/09/13 03:07, Robert Berger wrote:
> Hi,
>
> On 08/30/2013 07:56 PM, Darren Hart wrote:
>
>>> Is there any Linux distribution based on the Yocto project that lets
>>> me configure my embedded kernel with Xenomai? If not, has anybody got
>>> any experinece in adding Xenomai to the Yocto project?
>>
>> I am not aware of anyone using Xenomai with Yocto to date (although that
>> doesn't mean nobody is). Our Real-Time focus has been on the PREEMPT_RT
>> Linux kernel, which we do have recipes for.
>
> googling for meta-xenomai reveals:
>
> [1][2]
>
>>
>> It appears as though Xenomai has changed quite a bit over the years. If
>> my quick re-reading of their material is correct, the Xenomai core is
>> implemented as a Linux kernel module which can built in to a standard
>> Linux kernel?
>
> ... kind of ...
>
> kernel space:
>
> You need to apply a patch to a certain kernel version and configure the
> kernel afterwards.
>
> So for an ARM architecture there is a patch for the 3.8 kernel[3]
>
> user land:
>
> But unlike with preempt-rt you also need to build the Xenomai userland
> stuff.
>
>>
>> Out of curiosity, what sort of real-time requirements do you have?
>>
>
> That's a good point. Shameless self promotion [4].

Does your RT-threads have access to the full linux userland?
I'm thinking about D-BUS comms, Qt framework, networking stuff, ...
Or do they live in their own shell and communicate with the non-rt world 
via a dedicated system?
As well, have you tried/use it in a multi core context, where one core 
runs linux and the other one a RT kernel.

Regards,
Chris

>
> Regards,
>
> Robert
>
> [1] https://github.com/nojgosu/meta-xenomai
> [2] https://github.com/DrunkenInfant/beaglebone-xenomai
> [3]
> http://git.xenomai.org/?p=xenomai-head.git;a=tree;f=ksrc/arch/arm/patches;h=c6045f00819318970d6bba65c397609052c9414e;hb=HEAD
> [4] http://www.reliableembeddedsystems.com/pdfs/2010_03_04_rt_linux.pdf
>
>
> ..."A language that doesn't affect the way you think about programming
> is not worth knowing." - Anonymous
>
> My public pgp key is available,at:
> http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x90320BF1
>
>
> _______________________________________________
> yocto mailing list
> yocto@yoctoproject.org
> https://lists.yoctoproject.org/listinfo/yocto
>

Re: Embedded Linux with Xenomai support

[Asier]

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> Does your RT-threads have access to the full linux userland?
> I'm thinking about D-BUS comms, Qt framework, networking stuff, ...
> Or do they live in their own shell and communicate with the non-rt world
via a dedicated system?
> As well, have you tried/use it in a multi core context, where one core
runs linux and the other one a RT kernel.
>
The real-time and non real-time processes communicate mainly through shared
memory, and most of the time this communication follows a client-server
schema. I try to keep the rt-side as simple as possible (no Qt libraries,
no rt networking...). I do use real-time drivers for the CAN communication.

I haven't yet used a multicore processor.

Regards,

Asier




2013/9/3 Christian Gagneraud <chgans@gna.org>

> On 02/09/13 03:07, Robert Berger wrote:
>
>> Hi,
>>
>> On 08/30/2013 07:56 PM, Darren Hart wrote:
>>
>>  Is there any Linux distribution based on the Yocto project that lets
>>>> me configure my embedded kernel with Xenomai? If not, has anybody got
>>>> any experinece in adding Xenomai to the Yocto project?
>>>>
>>>
>>> I am not aware of anyone using Xenomai with Yocto to date (although that
>>> doesn't mean nobody is). Our Real-Time focus has been on the PREEMPT_RT
>>> Linux kernel, which we do have recipes for.
>>>
>>
>> googling for meta-xenomai reveals:
>>
>> [1][2]
>>
>>
>>> It appears as though Xenomai has changed quite a bit over the years. If
>>> my quick re-reading of their material is correct, the Xenomai core is
>>> implemented as a Linux kernel module which can built in to a standard
>>> Linux kernel?
>>>
>>
>> ... kind of ...
>>
>> kernel space:
>>
>> You need to apply a patch to a certain kernel version and configure the
>> kernel afterwards.
>>
>> So for an ARM architecture there is a patch for the 3.8 kernel[3]
>>
>> user land:
>>
>> But unlike with preempt-rt you also need to build the Xenomai userland
>> stuff.
>>
>>
>>> Out of curiosity, what sort of real-time requirements do you have?
>>>
>>>
>> That's a good point. Shameless self promotion [4].
>>
>
> Does your RT-threads have access to the full linux userland?
> I'm thinking about D-BUS comms, Qt framework, networking stuff, ...
> Or do they live in their own shell and communicate with the non-rt world
> via a dedicated system?
> As well, have you tried/use it in a multi core context, where one core
> runs linux and the other one a RT kernel.
>
> Regards,
> Chris
>
>
>
>> Regards,
>>
>> Robert
>>
>> [1] https://github.com/nojgosu/**meta-xenomai<https://github.com/nojgosu/meta-xenomai>
>> [2] https://github.com/**DrunkenInfant/beaglebone-**xenomai<https://github.com/DrunkenInfant/beaglebone-xenomai>
>> [3]
>> http://git.xenomai.org/?p=**xenomai-head.git;a=tree;f=**
>> ksrc/arch/arm/patches;h=**c6045f00819318970d6bba65c39760**
>> 9052c9414e;hb=HEAD<http://git.xenomai.org/?p=xenomai-head.git;a=tree;f=ksrc/arch/arm/patches;h=c6045f00819318970d6bba65c397609052c9414e;hb=HEAD>
>> [4] http://www.**reliableembeddedsystems.com/**
>> pdfs/2010_03_04_rt_linux.pdf<http://www.reliableembeddedsystems.com/pdfs/2010_03_04_rt_linux.pdf>
>>
>>
>> ..."A language that doesn't affect the way you think about programming
>> is not worth knowing." - Anonymous
>>
>> My public pgp key is available,at:
>> http://pgp.mit.edu:11371/pks/**lookup?op=get&search=**0x90320BF1<http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x90320BF1>
>>
>>
>> ______________________________**_________________
>> yocto mailing list
>> yocto@yoctoproject.org
>> https://lists.yoctoproject.**org/listinfo/yocto<https://lists.yoctoproject.org/listinfo/yocto>
>>
>>
> ______________________________**_________________
> yocto mailing list
> yocto@yoctoproject.org
> https://lists.yoctoproject.**org/listinfo/yocto<https://lists.yoctoproject.org/listinfo/yocto>
>

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Re: Embedded Linux with Xenomai support

[Marco]

Il 30/08/2013 12:34, Asier ha scritto:
> Hello all,
>
> I've just started studying the Yocto project, so I beg your pardon if
> this question has been already solved or it's just too easy (RT*M).
>
> I've got a working embedded system running Xenomai v2.5.5. The user
> interface has been developed with Qt Embedded. The kernel has been
> compiled using the ELinOS Embedded Linux distribution.
>
> Now, I want to change that interface to X11 so that I can use a desktop
> manager as well as some other X11 applications. The ELinOS distribution
> has an XServer, but it lacks a way of easily adding any desktop manager.
> Thus, I’m thinking about using another Linux distribution.
>
> That is how I have found the Yocto project. I think this can be the best
> solution for my new system.
>
> Is there any Linux distribution based on the Yocto project that lets me
> configure my embedded kernel with Xenomai? If not, has anybody got any
> experinece in adding Xenomai to the Yocto project?
>
> I'm using an Atom N270 chipset.
>
> Thanks in advance, best regards,
>
> Asier
>


Dear Asier,
As Yocto project participant and thanks to our experience with Xenomai 
(and RTAI) we at Koan can help you migrating or integrating any hard 
real time requirement into Yocto or as custom stand-alone solution 
creating or adapting a linux distribution with Xorg, and a desktop manager.
Feel free to contact me privately.

Cheers
-- 
Marco Cavallini | KOAN sas | Bergamo - Italia
  embedded and real-time software engineering
Phone:+39-035-255.235 - Fax:+39-178-22.39.748
       http://www.KoanSoftware.com