[meta-freescale] Questions on adapt yocto to a custom board

[andrea at perpic.it]

Il giorno gio, 06/08/2015 alle 16.05 +0200, Daiane Angolini ha scritto:
> On Thu, Aug 6, 2015 at 4:52 AM,  <andrea at perpic.it> wrote:
> > Hello everybody,
> 
> Hi

Thank you Daiane for your reply
> 
> >
> > It's some day that I'm surfing the net looking for the answer to my
> > question, I don't find any useful information because it looks to me
> > that all the solutions in in some way tricks and not clean solutions.
> >
> > My case:
> > I have an IMX53 custom board that is similar to loco but I added some
> > gpio and other function due to my application needs. (I think this
> > situation is common for everybody that produces dedicated hardware also
> > for other processors.)
> >
> > For adding complexity... All the documentation I can see on the net is
> > related OR to LTIB OR to IMX6 that uses a different kernel version so
> > files are in different locations or with different names.
> >
> > Finally my question:
> > What is the best way for deal with a new hardware?
> 
> Start with DDR script, go to u-boot development, go to kernel bring up.
Yes, It's what I am planning to do.
> 
> 
> > Adapt all the file from (u-boot / kernel) of the more similar board for
> > adapt to my needs or create a new board?
> 
> For u-boot case, use mainline and add your board in the latest stable
> (or upstream it)
> 
> For kernel, I prefer to not comment. There are several possible ways to go.
> 
> >
> > case 1: I think it's simples because what is already working continue to
> > work but I expect less flexibility because if I need to have a variant
> > of that board I need to manage two different layers depends on the board
> > I need to compile.
> >
> > case 2: create a new u-boot / kernel configuration for my board.
> > I expect more difficult at the beginning, find the right files to copy,
> > build the new versions of the firmware etc. Also every new changes on
> > the original board will be lost if I don't change them in my new files
> 
> In case you have the original board, it can be used as a benchmark
> during your bringup work.
I have IMX53qsb and my own board.
I can boot up the system and reach the prompt with small modifications
to u-boot. The socket for the mmc is a bit different and levels for card
detection are swapped. as I wrote before, I tried to keep my hardware as
similar as possible to the qsb.
> 
> If you don't have the original board. I'm not sure if the 2 cases are different.
> 
> 
> > What do you usually do?
> > What do you think are the problems with case 1 and case 2?
> >
> > Are you aware of any guide that I can follow for case 1 and / or case 2?
> > I am thinking about... iomux, flexcan initialization...
> 
> Have you read already the Porting guide for i.MX6? During the bringup,
> i.mx53 and i.mx6 is not ~that much~ different. Read that document and
> follow that guidelines to your board. If you don't know where to find
> it, let me know.
Are you referring to this one?
https://community.freescale.com/docs/DOC-100203

If it is I read it. At the moment I'm stuck with some file that are in
different location. For example I can't find any boards.cfg file in the
top level directory of u-boot. (Point 1 of Porting Bootloader)

find . -name board
./board
./post/board
./.pc/0001-change-boot-params.patch/board

maybe it was renamed?
the question that came in my head after I solve this... I created a
imx_(myboard) in my custom layer. How I tell to bitbake that it needs to
use my own configuration of u-boot?

> 
> 
> Daiane
> >
> > Any input will be appreciated
> > thank you for reading the long post
> > best regards
> > Andrea
> > --
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Thank you again
Andrea