[U-Boot-Users] Can U-boot Autodetect arch/ppc versusarch/powerpc from info in the uImage?

[Joakim Tjernlund]

> -----Original Message-----
> From: wd at denx.de [mailto:wd at denx.de] 
> Sent: den 4 december 2007 01:24
> To: Joakim Tjernlund
> Cc: 'Darcy Watkins'; u-boot-users at lists.sourceforge.net
> Subject: Re: [U-Boot-Users] Can U-boot Autodetect arch/ppc 
> versusarch/powerpc from info in the uImage?
> 
> Dear Jocke,
> 
> in message <057d01c83604$e0bb9ce0$5267a8c0 at Jocke> you wrote:
> >
> > Wolfgang, have you read the "Passing the OF tree to bootm 
> from board code?"
> > thread? Would you mind explain why it was removed and why 
> you don't think
> > it should be in u-boot?
> 
> Is there a thread to it? I can just find a single posting from you,
> without any replies...

Yes, there were a few replies.

> 
> But as for your question:
> 
> I cannot remember that, or when, or why exactly this feature was
> removed; I cannot even remember that it ever exited.

Was a long time ago, I too can't recall details.

> 
> But in genral I think it is a very bad idea  to  compile  the  device
> tree  into the U-Boot image, because that means you can never replace
> / change / update it. Also I fail to understand why you would want to
> do that. To me it seems much more sensible to  have  separate  U-Boot
> and  device  tree  images,  which can be replaced independent of each
> other. If you want, you can still store these in  adjacent  locations
> in flash. You can even attach these (you probably want to insert some
> padding  to  align on flash sector boundaries) images to for a single
> file which can be downloaded and flashed in a single operation.

I create a template tree that is compiled into u-boot. Then runtime
code adjusts/amends the tree as needed for that particular board.
We do have many diffrent boards that more or less look the same to
u-boot and kernel. For all these boards I do only one u-boot/kernel that
runs on all boards. Reason for that is too ease SW updates and save
space. This might not be the best methond of doing things but thats
how it has been the last 7 years so it is not something that is easy to
change now.

Even if the above method isn't something you want in u-boot I still
think there should be a way to pass the dev. tree to the bootm command
without using the environment/command arguments. For instance if
one has several trees, board code should be able decide which tree to use.
Command args should still overide this builtin tree.

 Jocke
> 
> As far as I understand your request, this offers all the same options
> you can get with a compiled in device tree blob, but with  the  added
> benefit of allowing many more things at the same time, too.
> 
> Maybe I'm missing something?
> 
> Best regards,
> 
> Wolfgang Denk
> 
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>