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

[Detlev Zundel]

Hi Marek,

> 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.

Ah, so it created what I would call a "memory mirroring" or "memory
aliasing", right?  Now I understand the problem, thanks.

Cheers
  Detlev

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