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

[Kumar Gala]

On Jun 27, 2007, at 3:57 PM, Segher Boessenkool wrote:

>>>>> -		ranges = <0 f8000000 00100000>;
>>>>> -		reg = <f8000000 00100000>;	// CCSRBAR 1M
>>>>> +		ranges = <00001000 f8001000 000ff000
>>>> [...]
>>>>> +		reg = <f8000000 00001000>;	// CCSRBAR
>>>>
>>>> This can't be right, and I suspect it will break any kernel  
>>>> access to
>>>> the first 0x1000 bytes of the CCSR_BAR space.  reg should actually
>>>> describe the register space of the SOC.  If ranges needs to specify
>>>> that, too, they should be able to be redundant.  But this looks  
>>>> like
>>>> a big hack, to me.  Am I missing something?
>>>
>>> "reg" and "ranges" can never overlap really.
>>>
>>> Is this the special case where the PHB is visible in
>>> PCI configuration space?
>>>
>>> Or, please explain what CCSR_BAR is...
>>
>> Its a 1M MMIO register space on the SOC (all device registers on  
>> the SOC live there).
>
> Okay, so it has nothing to do with PCI configuration space?

correct

> There is "BAR" in the name, so it is a movable range?  Where
> is the base address set?

in a MMIO register in the space itself.

> 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.

- k