[RFC v1] PCIe support for the Armada 370 and Armada XP SoCs

[Stephen Warren]

On 12/29/2012 01:09 AM, Thomas Petazzoni wrote:
> Dear Stephen Warren,
> 
> On Fri, 28 Dec 2012 16:49:15 -0700, Stephen Warren wrote:
> 
>>>> That's great. I've been thinking about this some more and one problem
>>>> we'll be facing is that none of the fake host bridges actually exist and
>>>> therefore don't have any official PCI IDs. What I did for Tegra was just
>>>> choose one of the nForce IDs, but that's obviously hackish. One solution
>>>> would be to convince somebody benevolent to sponsor an ID for this
>>>> particular purpose. I think Red Hat did so for Virtio.
>>>
>>> Indeed, that's a remaining problem to solve. Would be great to have
>>> some vendor sponsoring a few IDs for that. At least for a fake PCI Host
>>> Bridge and a fake PCI-to-PCI bridge.
>>
>> Is it actually necessary for a host/PCI bridge to show up on the PCI bus
>> as device 0?
> 
> I don't know, PCI experts are much better placed than me to answer this
> question. How is this related to the problem of PCI IDs ?

If a real PCI device exists, its configuration registers contain the PCI
IDs, so you just "use" them. If no real PCI device exists, yet should,
so you end up implementing a virtual device, the SW needs to decide
which PCI IDs to masquerade as, so you need to come up with some fake IDs.