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

[Marek Vasut]

Dear Detlev Zundel,

> Hi Marek,
> 
> > This reverts commit 69d26d09de1cb93e0a09ca71d9f0d41a66f0756a.
> > 
> > Apparently, this commit got mainline only because of OOT port and causes
> > breakage on board that is mainline. Revert.
> 
> To be honest, I don't understand what this patch or what the original
> patch did, nor through what OOT port this hit mainline and what breakage
> it causes on other boards.

It enabled some additional address bits on X board, allowing it to use full 
512MB of RAM. But because we don't have any other such configured board and X 
board isn't mainline, I reverted this patch. It caused trouble on new 256MB 
configuration of M28.

Once there'll be some module that needs different memory configuration (like X 
board) mainline, we'll add this here, but until then, I'd like to stick with 
common memory init.

> 
> So also I can read the sentence, I cannot make heads and tails of it.
> Can you please write commit messages that people like me can make some
> sense from?  I.e. answering the following questions would help me
> 
> - What does the original commit do? (its too late to change the original
>   commit)

Enabled additional address bits, to address full 512 MB of DRAM on the X board.

> - 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.

> - What breakage is caused on what boards?

See above.

> - Why can we revert the change without any problems?

Because we don't have any mainline port that used this feature.

> 
> Thanks
>   Detlev

Best regards,
Marek Vasut