about how to port YOCTO

about how to port YOCTO

[wangyang]

Hello!

Because YOCTO supports x86, arm and so on MCU. I just want to know about how to
port YOCTO to other MCU. Is it difficult, what's kind of knowledge  needed? 
Thanks

Re: about how to port YOCTO

[Yu Ke]

on 2011-5-16 11:31, wangyang wrote:
> Hello!
>
> Because YOCTO supports x86, arm and so on MCU. I just want to know about how to
> port YOCTO to other MCU. Is it difficult, what's kind of knowledge  needed?
> Thanks
>

Add another machine is not that difficult, as Yocto is designed to be 
highly customizable for different H/W. What you need is a BSP layer for 
your H/W, it is basically the H/W specific configuration, e.g. the 
kernel config, graphics config.

the BSP Guide 
(http://www.yoctoproject.org/docs/bsp-guide/bsp-guide.html) has good 
info on how to write BSP. Also you can find some example from existing 
BSP, like meta-intel BSP 
(http://git.pokylinux.org/cgit/cgit.cgi/meta-intel/)

Regards
Ke

Re: about how to port YOCTO

[Gary Thomas]

On 05/16/2011 01:10 AM, Yu Ke wrote:
> on 2011-5-16 11:31, wangyang wrote:
>> Hello!
>>
>> Because YOCTO supports x86, arm and so on MCU. I just want to know about how to
>> port YOCTO to other MCU. Is it difficult, what's kind of knowledge needed?
>> Thanks
>>
>
> Add another machine is not that difficult, as Yocto is designed to be highly customizable for different H/W. What you need is a BSP layer for your H/W, it is basically the H/W
> specific configuration, e.g. the kernel config, graphics config.
>
> the BSP Guide (http://www.yoctoproject.org/docs/bsp-guide/bsp-guide.html) has good info on how to write BSP. Also you can find some example from existing BSP, like meta-intel BSP
> (http://git.pokylinux.org/cgit/cgit.cgi/meta-intel/)

Beyond that, there are some bigger issues.  Remember that Yocto is
just packaging for a Linux kernel and the user tools that surround
it.  Before you can add a new machine, especially one with a different
architecture as the original email hints, you have to have a working
toolchain (GCC and friends), Linux kernel, GLIBC, etc.

-- 
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
------------------------------------------------------------

Re: about how to port YOCTO

[Gary Thomas]

On 05/16/2011 07:20 PM, wangyang wrote:
>> Remember that Yocto is
>> just packaging for a Linux kernel and the user tools that surround
>> it.
>
> In other words, if I want to use Yocto to package Linux kernel and the user
> tools for new MCU,I must port Linux kernel and toolchain and GLIBC, etc. It is
> right?
>
> What Yocto do is just packaging mainstream Linux kernel(from
> http://www.kernel.org/) and something with it for different needs, it is right?

Correct.  Yocto isn't really for porting the tools to a platform,
but rather something to help you build [embedded] systems to run
on the platform.

n.b. it's polite to keep such discussions on the mailing list so that
everyone benefits.

-- 
------------------------------------------------------------
Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
------------------------------------------------------------

Re: about how to port YOCTO

[wangyang]

Mr Gary:
Thank you for your answer.

> -----Original Message-----
> From: Gary Thomas [mailto:gary@mlbassoc.com]
> Sent: Tuesday, May 17, 2011 7:11 PM
> To: wangyang
> Cc: yocto@yoctoproject.org
> Subject: Re: [yocto] about how to port YOCTO
> 
> On 05/16/2011 07:20 PM, wangyang wrote:
> >> Remember that Yocto is
> >> just packaging for a Linux kernel and the user tools that surround
> >> it.
> >
> > In other words, if I want to use Yocto to package Linux kernel and the user
> > tools for new MCU,I must port Linux kernel and toolchain and GLIBC, etc. It
is
> > right?
> >
> > What Yocto do is just packaging mainstream Linux kernel(from
> > http://www.kernel.org/) and something with it for different needs, it is
right?
> 
> Correct.  Yocto isn't really for porting the tools to a platform,
> but rather something to help you build [embedded] systems to run
> on the platform.
> 
> n.b. it's polite to keep such discussions on the mailing list so that
> everyone benefits.
> 
> --
> ------------------------------------------------------------
> Gary Thomas                 |  Consulting for the
> MLB Associates              |    Embedded world
> ------------------------------------------------------------

Re: about how to port YOCTO

[Pedro Sanchez]

On 05/16/2011 03:10 AM, Yu Ke wrote:
> on 2011-5-16 11:31, wangyang wrote:
>> Hello!
>>
>> Because YOCTO supports x86, arm and so on MCU. I just want to know
>> about how to
>> port YOCTO to other MCU. Is it difficult, what's kind of knowledge
>> needed?
>> Thanks
>>
>
> Add another machine is not that difficult, as Yocto is designed to be
> highly customizable for different H/W. What you need is a BSP layer for
> your H/W, it is basically the H/W specific configuration, e.g. the
> kernel config, graphics config.
>
> the BSP Guide
> (http://www.yoctoproject.org/docs/bsp-guide/bsp-guide.html) has good
> info on how to write BSP. Also you can find some example from existing
> BSP, like meta-intel BSP
> (http://git.pokylinux.org/cgit/cgit.cgi/meta-intel/)
>
> Regards
> Ke
> _______________________________________________
> yocto mailing list
> yocto@yoctoproject.org
> https://lists.yoctoproject.org/listinfo/yocto

When I clone the yocto git repo (git://git.pokylinux.org/poky.git) I 
don't get any of these meta-xxx directories that the BSP guide talks 
about. They seem to be kept in a separate git repository.

My question is then, once I create my meta-xxx directory structure, how 
is it hooked up to the overall poky build infrastructure? I've failed to 
find an answer in the BSP guide so far.

Thanks,

-- 
Pedro

Re: about how to port YOCTO

[Tom Zanussi]

On Mon, 2011-05-16 at 07:19 -0700, Pedro Sanchez wrote:
> On 05/16/2011 03:10 AM, Yu Ke wrote:
> > on 2011-5-16 11:31, wangyang wrote:
> >> Hello!
> >>
> >> Because YOCTO supports x86, arm and so on MCU. I just want to know
> >> about how to
> >> port YOCTO to other MCU. Is it difficult, what's kind of knowledge
> >> needed?
> >> Thanks
> >>
> >
> > Add another machine is not that difficult, as Yocto is designed to be
> > highly customizable for different H/W. What you need is a BSP layer for
> > your H/W, it is basically the H/W specific configuration, e.g. the
> > kernel config, graphics config.
> >
> > the BSP Guide
> > (http://www.yoctoproject.org/docs/bsp-guide/bsp-guide.html) has good
> > info on how to write BSP. Also you can find some example from existing
> > BSP, like meta-intel BSP
> > (http://git.pokylinux.org/cgit/cgit.cgi/meta-intel/)
> >
> > Regards
> > Ke
> > _______________________________________________
> > yocto mailing list
> > yocto@yoctoproject.org
> > https://lists.yoctoproject.org/listinfo/yocto
> 
> When I clone the yocto git repo (git://git.pokylinux.org/poky.git) I 
> don't get any of these meta-xxx directories that the BSP guide talks 
> about. They seem to be kept in a separate git repository.
> 

Hi,

The BSP guide uses some meta-intel layers as examples, but just as
examples - we don't really want to put pointers to specific layers in
there.  (Are those the meta-xxx directories you're talking about?) There
is a list of all the repos including meta-intel here:

http://git.yoctoproject.org/

But I guess you have to know to look to find them - we should probably
add something explicit somewhere listing the specific BSP repos.  Maybe
on the Downloads page in the BSP section?

http://www.yoctoproject.org/download

> My question is then, once I create my meta-xxx directory structure, how 
> is it hooked up to the overall poky build infrastructure? I've failed to 
> find an answer in the BSP guide so far.
> 

The BSP guide is actually a section out of the Reference Manual here.
That contains instructions on how to use layers:

http://www.yoctoproject.org/docs/poky-ref-manual/poky-ref-manual.html#usingpoky-changes-layers

but maybe there should be something about that in the BSP Guide too.

For the meta-intel layer, once you have it, there are instructions in
the README about adding the layer to bblayers.conf, which is what you
want to do to get it hooked into the overall build structure:

"Having done that, and assuming you cloned the 'meta-intel' repository
at the top-level of your yocto build tree, you can build a crownbay
image by adding the location of the meta-crownbay layer to
bblayers.conf e.g.:

  yocto/meta-intel/meta-crownbay \
"

But I agree, we should probably have some more explicit instructions on
this in the BSP developer's Guide - I'll submit a patch to do that...

Thanks,

Tom


> Thanks,
>