Re: [PATCH] of: treat PCI config space as IORESOURCE_MEM type

[Kumar Gala]

On May 30, 2014, at 3:37 PM, Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Fri, May 30, 2014 at 02:41:17AM +0100, Liviu Dudau wrote:
> 
>> Agree, I'm only concerned that if this ECAM config space gets added to
>> the list of pci_host_bridge windows it will be indistinguishable from
>> IORESOURCE_MEM resources and pci_create_root_bus() will add it to the
>> bus and allow devices present on that bus to be assigned addresses from
>> that range. Which might not be what one wants for certain BARs.
> 
> I wouldn't worry about supporting config in ranges. ECAM is the
> logical use for config ranges, but it isn't specified and probably
> will never be.
> 
> Will's driver the is the only driver I've seen to support ECAM and it
> didn't use ranges.

I expect with 64-bit parts we will see more use of ECAM, I think the reason its not used much is because of the address space it chews up, but that becomes less of an issue with LPAE or 64-bit parts with larger physical address spaces.

- k

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