[PATCH 04/10] bus: introduce an Marvell EBU MBus driver

Jason Gunthorpe jgunthorpe at obsidianresearch.com
Fri Mar 8 12:50:23 EST 2013


On Fri, Mar 08, 2013 at 03:41:29PM +0000, Arnd Bergmann wrote:

> If you want the boot loader to tell the kernel to autoconfigure all the
> mappings, an absent ranges property would be the right thing. This makes
> a lot of sense if you want to go fully dynamic, but I thought that you
> were not attempting to go that far yet.
> 
> I think we really want the ranges to be populated at run-time though,
> and have it match exactly the windows that we decide to put in, so that
> of_address_translate works.

Right, so taking these two paragraphs together - if you have an absent
ranges you are imagining that the mbus driver would write out a new
fully populated ranges to the DTB? That would be necessary to keep
of_address_translate working.

If so we are talking about exactly the same thing - the in memory DTB
would still have working address translation.

An absent ranges makes some sense from a spec perspective - however do we
have the kernel infrastructure to grow an in memory DTB node?

Jason



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