[U-Boot] [PATCH] i.MX28: Fix ref_cpu clock setup

[Robert Deliën]

Hi Marek,

> git rebase -i HEAD~3
> (if you have the patch you want to rework 3 patches deep)
> Change "pick" to the left of the patch to "edit"
> Do the change in the file.
> git add <file>
> git rebase --continue
> <submit>

May be tonight, at my hotel room.

> Lowering the clock to what ?

Down to 137MHz works for me. That's way too low, but at least it keeps my board
going.
But there's nothing wrong with a frequency of 206MHz, as configured currently; We
just should up the CAS to RAS delay to 5 cycles, from the 3 configured currently.
Perhaps others parameters need a little attention too, but there are so many registers
for DDR to check here...

> I was pondering about this too, the settings in
> spl_mem_init are for DENX m28 board, so maybe someone should abstract that out.

I'm not happy with it either, but the way it is now seems to be the most common one.
And due to the huge amount of registers, I doubt if it could be abstracted nicely,
without turning it into an even bigger mess. I'm afraid there's little alternatives to tuning
DDR parameters for each board separately.

Cheers,

        Robert.