Virtual addresses in arch/powerpc/boot/dts/tqm8548*.dts ?

Paul Walmsley paul at pwsan.com
Wed Aug 31 11:55:48 EST 2011


On Tue, 30 Aug 2011, Gary Thomas wrote:

> On 2011-08-30 15:43, Paul Walmsley wrote:
> 
> > So are these addresses virtual?  My (perhaps incorrect) understanding of
> > the device tree files was that they were intended to describe the physical
> > memory map, rather than the virtual memory map.  Or does this PowerPC
> > variant have the ability to dynamically change its own physical address
> > decoding?  Or is something else going on?
> 
> These addresses correspond to the internal registers which can be moved. 
> The default address is set by hardware at reset time (check out the 
> documentation on the hardware reset word).  Obviously one board is 
> strapped for the IMMR at one address, another board at a different 
> address.  I almost always configure my boards to use 0xF0000000 for the 
> IMMR.

Got it.  Thanks Gary.


- Paul


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