[U-Boot] [PATCH 1/3] Revert "i.MX28: Enable additional DRAM address bits"

[Marek Vasut]

Dear Detlev Zundel,

> Hi Marek,
> 
> [...]
> 
> >> - Why was the change made in the first place and for what OOT port?
> > 
> > Change of a DRAM configuration register that enabled additional
> > address bit, at address 512MB of DRAM. Though this caused memory hole
> > on our M28 module with 256MB of DRAM, which _is_ mainline. X board is
> > OOT and never will be mainlined I guess.
> 
> I still do not understand this fully.  What exactly is this "memory
> hole" and why is it fatal?  As far as I can remember, there are always
> some holes in the adress map, so why is this special?

No, this one created this layout on our 256 MB module:

[chunk of memory][<- same thing][chunk of memory][<- same thing]

so get_ram_size() didn't work with it and it actually overwrote part of the U-
Boot etc.

> 
> Apart from that, I think most of these answers should go into the commit
> message to understand what is happening.

Agreed

> Thanks in advance
>   Detlev

Best regards,
Marek Vasut