from where to start to port some patches to a newer kernel

from where to start to port some patches to a newer kernel

[Ivan Sergio Borgonovo]

I'm playing with an imx28evk based board.

The manufacturer supports just the old freescale kernel and and I have 
their layer to make it work in Yocto.
They didn't define a new board, they just patched the bsp of imx28evk.

I'd like to get an idea about how hard it could be to port those patches 
to a newer kernel.
Which kernel would you suggest?

What procedure do you suggest to set up a dev environment that will let 
me try start hacking easily?

I was thinking about:
* creating a copy of their layer, getting rid of their kernel patches
* uncomment
   PREFERRED_PROVIDER_virtual/kernel = "linux-fslc"
   and
   PREFERRED_VERSION_linux-fslc = "3.%"
   in local.conf
* build image-core-minimal
* start to add their ported patch back in the copy of their layer.

Hoping that once I start they will join.

thanks

-- 
Ivan Sergio Borgonovo
http://www.webthatworks.it

Re: from where to start to port some patches to a newer kernel

[Otavio Salvador]

On Tue, Oct 20, 2015 at 8:54 PM, Ivan Sergio Borgonovo
<mail@webthatworks.it> wrote:
> I'm playing with an imx28evk based board.
>
> The manufacturer supports just the old freescale kernel and and I have their
> layer to make it work in Yocto.
> They didn't define a new board, they just patched the bsp of imx28evk.
>
> I'd like to get an idea about how hard it could be to port those patches to
> a newer kernel.
> Which kernel would you suggest?
>
> What procedure do you suggest to set up a dev environment that will let me
> try start hacking easily?
>
> I was thinking about:
> * creating a copy of their layer, getting rid of their kernel patches
> * uncomment
>   PREFERRED_PROVIDER_virtual/kernel = "linux-fslc"
>   and
>   PREFERRED_VERSION_linux-fslc = "3.%"
>   in local.conf
> * build image-core-minimal
> * start to add their ported patch back in the copy of their layer.
>
> Hoping that once I start they will join.

It depends on how:

 - much access you have to information
 - is the board already supported by Linux mainline?
 - compare both kernel sources to see the changes done by the manufactor

To be honest, I would start at U-Boot and not the kernel as it is
easier to hack and also allow for you to learn more about the board
specifics.

-- 
Otavio Salvador                             O.S. Systems
http://www.ossystems.com.br        http://code.ossystems.com.br
Mobile: +55 (53) 9981-7854            Mobile: +1 (347) 903-9750

Re: from where to start to port some patches to a newer kernel

[Ivan Sergio Borgonovo]

On 21/10/2015 01:35, Otavio Salvador wrote:

> It depends on how:

>   - much access you have to information

I've a working yocto layer that use freescale 2.6.35 kernel that 
includes some minor changes to init to set up a display. tslib and some 
kernel patches.
Most of the patches are related to the attached display.
Others look like backports or pin configuration (none of which seems to 
be "boot" related).
No pathces for uboot.

>   - is the board already supported by Linux mainline?

Up to my understanding of the patches, the board shouldn't be very 
different from the original imx28evk so it probably may be supported and 
I may just have to reassign some pins and port the display patches.

>   - compare both kernel sources to see the changes done by the manufactor

Ok, going back to re-read my books. Anyway, which kernel would you 
suggest considering the board doesn't look that different from the 
original imx28evk?

> To be honest, I would start at U-Boot and not the kernel as it is
> easier to hack and also allow for you to learn more about the board
> specifics.

Crossing fingers I may not have to learn how uboot works right now.

thanks

-- 
Ivan Sergio Borgonovo
http://www.webthatworks.it

Re: from where to start to port some patches to a newer kernel

[Otavio Salvador]

On Tue, Oct 20, 2015 at 10:55 PM, Ivan Sergio Borgonovo
<mail@webthatworks.it> wrote:
> On 21/10/2015 01:35, Otavio Salvador wrote:
>
>> It depends on how:
>
>
>>   - much access you have to information
>
>
> I've a working yocto layer that use freescale 2.6.35 kernel that includes
> some minor changes to init to set up a display. tslib and some kernel
> patches.
> Most of the patches are related to the attached display.
> Others look like backports or pin configuration (none of which seems to be
> "boot" related).
> No pathces for uboot.

So first thing I would do is to move for U-Boot mainline (or here, u-boot-fslc).

>>   - is the board already supported by Linux mainline?
>
>
> Up to my understanding of the patches, the board shouldn't be very different
> from the original imx28evk so it probably may be supported and I may just
> have to reassign some pins and port the display patches.
>
>>   - compare both kernel sources to see the changes done by the manufactor
>
>
> Ok, going back to re-read my books. Anyway, which kernel would you suggest
> considering the board doesn't look that different from the original
> imx28evk?

I would take linux-fslc 4.1 branch or linux mainline (4.3-rcX).

>> To be honest, I would start at U-Boot and not the kernel as it is
>> easier to hack and also allow for you to learn more about the board
>> specifics.
>
>
> Crossing fingers I may not have to learn how uboot works right now.

It is a nice software and worth learning it ;-)

-- 
Otavio Salvador                             O.S. Systems
http://www.ossystems.com.br        http://code.ossystems.com.br
Mobile: +55 (53) 9981-7854            Mobile: +1 (347) 903-9750

Re: from where to start to port some patches to a newer kernel

[Ivan Sergio Borgonovo]

On 10/21/2015 06:53 PM, Otavio Salvador wrote:

> So first thing I would do is to move for U-Boot mainline (or here, u-boot-fslc).

[snip]

> I would take linux-fslc 4.1 branch or linux mainline (4.3-rcX).

Sorry for trying hard to be as much as I can a freeloader ;) but which
one is going to be the one that once I finish my work I'll see supported
by others?
Or maybe to suggest a different opportunity:
which one do you think has more chances to be adopted by the
manufacturer once I'll knock at their door and say "look what a nice
work I've done for free, you'll get much love if you take care of it"?
I'm not sure I'm going to succeed, but why shouldn't I try?

>> Crossing fingers I may not have to learn how uboot works right now.

> It is a nice software and worth learning it ;-)

I've a long list of things I'd like to learn earlier and currently with
a higher return than uboot.
First I'll have to re-read how to hack a kernel in yocto ;)

-- 
Ivan Sergio Borgonovo
http://www.webthatworks.it

Re: from where to start to port some patches to a newer kernel

[Otavio Salvador]

On Wed, Oct 21, 2015 at 3:40 PM, Ivan Sergio Borgonovo
<mail@webthatworks.it> wrote:
> On 10/21/2015 06:53 PM, Otavio Salvador wrote:
>
>> So first thing I would do is to move for U-Boot mainline (or here, u-boot-fslc).
>
> [snip]
>
>> I would take linux-fslc 4.1 branch or linux mainline (4.3-rcX).
>
> Sorry for trying hard to be as much as I can a freeloader ;) but which
> one is going to be the one that once I finish my work I'll see supported
> by others?

None; it is your duty to maintain it. The best is always to mainline
the source code but as it is maintained by community it cannot be
expected that someone will keep an eye on it.

> Or maybe to suggest a different opportunity:
> which one do you think has more chances to be adopted by the
> manufacturer once I'll knock at their door and say "look what a nice
> work I've done for free, you'll get much love if you take care of it"?
> I'm not sure I'm going to succeed, but why shouldn't I try?

The linux-fslc is a good option as it is close to mainline and you can
try to convince the manufacturer it would be beneficial for them.
Otherwise you can hire someone to do the maintenance work.

>>> Crossing fingers I may not have to learn how uboot works right now.
>
>> It is a nice software and worth learning it ;-)
>
> I've a long list of things I'd like to learn earlier and currently with
> a higher return than uboot.
> First I'll have to re-read how to hack a kernel in yocto ;)

Good luck!

-- 
Otavio Salvador                             O.S. Systems
http://www.ossystems.com.br        http://code.ossystems.com.br
Mobile: +55 (53) 9981-7854            Mobile: +1 (347) 903-9750