Re: [PATCH 5/5] arm: dts: Convert mvebu device tree files to 64bits

From: Thomas Petazzoni
Date: Thu Mar 21 2013 - 17:15:33 EST


Dear Jason Gunthorpe,

On Thu, 21 Mar 2013 14:55:45 -0600, Jason Gunthorpe wrote:

> Or, better, locate all the internal registers above 8G and use
> contiguous DRAM mapping from 0 -> 8GB

I see two potential issues with this idea:

*) It only works when LPAE is enabled, so we would have to have
different internal register addresses depending on whether LPAE is
enabled or not. Probably not impossible, but not very
straightforward either.

*) It would require Linux to change the internal registers address
(for now the kernel relies on the bootloader). The problem is that
we can't do it early enough to preserve the earlyprintk
functionality. Maybe you have suggestions on how to achieve that?

Best regards,

Thomas
--
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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