[PATCH 09/15] [POWERPC] 86xx: Add uli1575 pci-bridge sector to MPC8641HPCN dts file.

Andy Fleming afleming at freescale.com
Sat Jun 30 10:09:07 EST 2007


On Jun 27, 2007, at 17:51, Kumar Gala wrote:

>
>>>> What is the relationship between (in the example) the address
>>>> ranges x'f800_0000+1000 and x'f800_1000+ff000?
>>>
>>> uugh, not sure what that's all about.
>>
>> Reading back I see that the CCSR region is 1MB, and only the
>> first 4kB are for this PHB.  What is the rest of this range
>> used for -- devices on this PCI bus, other SoC devices, ...?
>
> No, the first 4kB are SOC/platform level config registers (high  
> level window setup, CCSR location, etc).
>
> The PHB registers are somewhere in the middle (0x8000, I think).   
> All the children devices (enet, PHBs, etc) live in the 1M block.
>
> I think my original idea was the reg property on the SOC node was  
> for the first 4k block that held the SOC config registers.  I think  
> what Wade did is correct since the reg property on the SOC node  
> isnt going to get translated through the ranges property and that  
> they should be mutually exclusive.


Ok, I'm thinking we don't need the reg property at all, or that it  
can be of size 0 or 4 (the CCSRBAR, itself).  If we need to access  
registers in the first 4k, we can define reg properties for the  
submodules which are in the CCSR space.

My issue with the submitted option is that the first 4k don't really  
belong to an SOC "device", they are just the first 4k of registers.   
In this case, they are the Local Access Window registers.  It sort of  
feels like we're arbitrarily deciding assigning the first 4k to the  
"SOC".  If that's what we want to do, I'd like if we put it in  
booting-without-of.txt.  Actually, it should go there, anyway.

Andy



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