embedding dtb file into kernel

embedding dtb file into kernel

[K Richard Pixley]

I'm having trouble figuring out how to embed a dtb file into my kernel.  I'm thinking that there should be a standard, architecture independent facility for this akin to initramfs, yes?

Could someone please either point me to the standard facility, relevant doc, a currently building board that uses the standard facility, or outline what needs to be done to do this with a new board?

If it matters, (I can't think why it would), I'm working with powerpc on a 3.10 kernel.  But if there are better facilities in other versions I'd appreciate hearing about that too.

Thank you in advance.

--rich

Re: embedding dtb file into kernel

[christophe leroy]

Le 13/02/2015 18:41, K Richard Pixley a écrit :
> I'm having trouble figuring out how to embed a dtb file into my 
> kernel.  I'm thinking that there should be a standard, architecture 
> independent facility for this akin to initramfs, yes?
>
> Could someone please either point me to the standard facility, 
> relevant doc, a currently building board that uses the standard 
> facility, or outline what needs to be done to do this with a new board?
>
> If it matters, (I can't think why it would), I'm working with powerpc 
> on a 3.10 kernel.  But if there are better facilities in other 
> versions I'd appreciate hearing about that too.
>
> Thank you in advance.
>

Hi,

The device tree (DTB file) is not supposed to be embedded into the 
kernel but loaded independently by the boot loader (for instance Uboot).
Then a pointer to the device tree is handed over by Uboot to the kernel 
when calling the _start function.

You also have in arch/powerpc/boot/ a facility called cuboot which 
allows to create a ppcboot image with kernel and device tree bound together.

Christophe

---
L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
http://www.avast.com

Re: embedding dtb file into kernel

[Stefano Babic]

Hi Richard,

On 13/02/2015 18:41, K Richard Pixley wrote:
> I'm having trouble figuring out how to embed a dtb file into my kernel. 
> I'm thinking that there should be a standard, architecture independent
> facility for this akin to initramfs, yes?
> 
> Could someone please either point me to the standard facility, relevant
> doc, a currently building board that uses the standard facility, or
> outline what needs to be done to do this with a new board?
> 
> If it matters, (I can't think why it would), I'm working with powerpc on
> a 3.10 kernel.  But if there are better facilities in other versions I'd
> appreciate hearing about that too.
> 

Maybe it is worth to take a look at the fitImage, which can embed pretty
much anything (including DTB).

Best regards,
Stefano Babic

-- 
=====================================================================
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic@denx.de
=====================================================================

Re: embedding dtb file into kernel

[Sam Protsenko]

On Thu, Feb 12, 2015 at 9:33 PM, K Richard Pixley
<rpixley@graphitesystems.com> wrote:
> I'm having trouble figuring out how to embed a dtb file into my kernel.  I'm
> thinking that there should be a standard, architecture independent facility
> for this akin to initramfs, yes?
>
> Could someone please either point me to the standard facility, relevant doc,
> a currently building board that uses the standard facility, or outline what
> needs to be done to do this with a new board?
>
> If it matters, (I can't think why it would), I'm working with powerpc on a
> 3.10 kernel.  But if there are better facilities in other versions I'd
> appreciate hearing about that too.
>
> Thank you in advance.
>
> --rich
> --
> To unsubscribe from this list: send the line "unsubscribe linux-embedded" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Look into Documentation/powerpc/bootwrapper.txt.
It reveals that there is "wrapper" script which does the trick and
this script should be used
via Makefile. Both "wrapper" script and Makefile resides in
arch/powerpc/boot/ directory.
I think you can figure out how to use it properly from that documentation.

Re: embedding dtb file into kernel

[Hugh Blemings]

On 13/02/2015 17:10, Rob Landley wrote:
> On 02/12/2015 06:56 PM, Tim Bird wrote:
>>
>>
>> On 02/12/2015 02:30 PM, K Richard Pixley wrote:
>>> On 2/12/15 14:01 , Tim Bird wrote:
>>>> On 02/12/2015 11:33 AM, K Richard Pixley wrote:
>>>>> I'm having trouble figuring out how to embed a dtb file into my kernel.
>>>>> I'm thinking that there should be a standard, architecture independent
>>>>> facility for this akin to initramfs, yes?
>>>>>
>>>>> Could someone please either point me to the standard facility, relevant
>>>>> doc, a currently building board that uses the standard facility, or
>>>>> outline what needs to be done to do this with a new board?
>>>>>
>>>>> If it matters, (I can't think why it would), I'm working with powerpc on
>>>>> a 3.10 kernel.  But if there are better facilities in other versions I'd
>>>>> appreciate hearing about that too.
>>>> The normal method is just to cat the two files together, like so:
>>>>    $ cat zImage <filename>.dtb > zImage_w_dtb
>>>>
>>>> See https://community.freescale.com/thread/315543 for one example, on ARM.
>>>> I'm not sure what the status is for appended DTBs on powerpc, but it's
>>>> easy enough you can just try it and see what happens.
>>>>    -- Tim
>>>
>>> Thanks!
>>>
>>> How do I tell the kernel where to find that dtb?  Is there a relevant
>>> config option?
>>
>> Usually you make the dtb from sources in the kernel.
>> I don't know how it works on powerpc, but on arm, the .dts
>> files are located in arch/arm/boot/dts, and you would make
>> the dtb for the corresponding "foo.dts" source
>> by typing:
>> $ make foo.dtb
>
> It's probably somewhere in:
>
> https://www.kernel.org/doc/Documentation/devicetree/booting-without-of.txt

Worth pointing out the folk over in linuxppc-dev are usually pretty 
friendly, may be able to help out with this too. 
https://lists.ozlabs.org/listinfo/linuxppc-dev

Cheers,
Hugh

Re: embedding dtb file into kernel

[Rob Landley]

On 02/12/2015 06:56 PM, Tim Bird wrote:
> 
> 
> On 02/12/2015 02:30 PM, K Richard Pixley wrote:
>> On 2/12/15 14:01 , Tim Bird wrote:
>>> On 02/12/2015 11:33 AM, K Richard Pixley wrote:
>>>> I'm having trouble figuring out how to embed a dtb file into my kernel.
>>>> I'm thinking that there should be a standard, architecture independent
>>>> facility for this akin to initramfs, yes?
>>>>
>>>> Could someone please either point me to the standard facility, relevant
>>>> doc, a currently building board that uses the standard facility, or
>>>> outline what needs to be done to do this with a new board?
>>>>
>>>> If it matters, (I can't think why it would), I'm working with powerpc on
>>>> a 3.10 kernel.  But if there are better facilities in other versions I'd
>>>> appreciate hearing about that too.
>>> The normal method is just to cat the two files together, like so:
>>>   $ cat zImage <filename>.dtb > zImage_w_dtb
>>>
>>> See https://community.freescale.com/thread/315543 for one example, on ARM.
>>> I'm not sure what the status is for appended DTBs on powerpc, but it's
>>> easy enough you can just try it and see what happens.
>>>   -- Tim
>>
>> Thanks!
>>
>> How do I tell the kernel where to find that dtb?  Is there a relevant 
>> config option?
> 
> Usually you make the dtb from sources in the kernel.
> I don't know how it works on powerpc, but on arm, the .dts
> files are located in arch/arm/boot/dts, and you would make
> the dtb for the corresponding "foo.dts" source
> by typing:
> $ make foo.dtb

It's probably somewhere in:

https://www.kernel.org/doc/Documentation/devicetree/booting-without-of.txt

Rob

Re: embedding dtb file into kernel

[Tim Bird]

On 02/12/2015 02:30 PM, K Richard Pixley wrote:
> On 2/12/15 14:01 , Tim Bird wrote:
>> On 02/12/2015 11:33 AM, K Richard Pixley wrote:
>>> I'm having trouble figuring out how to embed a dtb file into my kernel.
>>> I'm thinking that there should be a standard, architecture independent
>>> facility for this akin to initramfs, yes?
>>>
>>> Could someone please either point me to the standard facility, relevant
>>> doc, a currently building board that uses the standard facility, or
>>> outline what needs to be done to do this with a new board?
>>>
>>> If it matters, (I can't think why it would), I'm working with powerpc on
>>> a 3.10 kernel.  But if there are better facilities in other versions I'd
>>> appreciate hearing about that too.
>> The normal method is just to cat the two files together, like so:
>>   $ cat zImage <filename>.dtb > zImage_w_dtb
>>
>> See https://community.freescale.com/thread/315543 for one example, on ARM.
>> I'm not sure what the status is for appended DTBs on powerpc, but it's
>> easy enough you can just try it and see what happens.
>>   -- Tim
> 
> Thanks!
> 
> How do I tell the kernel where to find that dtb?  Is there a relevant 
> config option?

Usually you make the dtb from sources in the kernel.
I don't know how it works on powerpc, but on arm, the .dts
files are located in arch/arm/boot/dts, and you would make
the dtb for the corresponding "foo.dts" source
by typing:
$ make foo.dtb

   -- Tim

Re: embedding dtb file into kernel

[K Richard Pixley]

On 2/12/15 14:01 , Tim Bird wrote:
> On 02/12/2015 11:33 AM, K Richard Pixley wrote:
>> I'm having trouble figuring out how to embed a dtb file into my kernel.
>> I'm thinking that there should be a standard, architecture independent
>> facility for this akin to initramfs, yes?
>>
>> Could someone please either point me to the standard facility, relevant
>> doc, a currently building board that uses the standard facility, or
>> outline what needs to be done to do this with a new board?
>>
>> If it matters, (I can't think why it would), I'm working with powerpc on
>> a 3.10 kernel.  But if there are better facilities in other versions I'd
>> appreciate hearing about that too.
> The normal method is just to cat the two files together, like so:
>   $ cat zImage <filename>.dtb > zImage_w_dtb
>
> See https://community.freescale.com/thread/315543 for one example, on ARM.
> I'm not sure what the status is for appended DTBs on powerpc, but it's
> easy enough you can just try it and see what happens.
>   -- Tim

Thanks!

How do I tell the kernel where to find that dtb?  Is there a relevant 
config option?

--rich

Re: embedding dtb file into kernel

[Tim Bird]

On 02/12/2015 11:33 AM, K Richard Pixley wrote:
> I'm having trouble figuring out how to embed a dtb file into my kernel.  
> I'm thinking that there should be a standard, architecture independent 
> facility for this akin to initramfs, yes?
> 
> Could someone please either point me to the standard facility, relevant 
> doc, a currently building board that uses the standard facility, or 
> outline what needs to be done to do this with a new board?
> 
> If it matters, (I can't think why it would), I'm working with powerpc on 
> a 3.10 kernel.  But if there are better facilities in other versions I'd 
> appreciate hearing about that too.

The normal method is just to cat the two files together, like so:
 $ cat zImage <filename>.dtb > zImage_w_dtb

See https://community.freescale.com/thread/315543 for one example, on ARM.
I'm not sure what the status is for appended DTBs on powerpc, but it's
easy enough you can just try it and see what happens.
 -- Tim

embedding dtb file into kernel

[K Richard Pixley]

I'm having trouble figuring out how to embed a dtb file into my kernel.  
I'm thinking that there should be a standard, architecture independent 
facility for this akin to initramfs, yes?

Could someone please either point me to the standard facility, relevant 
doc, a currently building board that uses the standard facility, or 
outline what needs to be done to do this with a new board?

If it matters, (I can't think why it would), I'm working with powerpc on 
a 3.10 kernel.  But if there are better facilities in other versions I'd 
appreciate hearing about that too.

Thank you in advance.

--rich