MSI support on Linux PCI implementation for Ocotea

[Shawn Jin]

Hi Ben,

> Now, regarding MSI, as you have noticed, the situation isn't great. I'm
> currently in the middle of reworking our interrupt management (and
> interrupt numbers allocation layer) and Michael Ellermann is looking at
> the MSI issue in parallel.

Just one point about MSI(-X) message address and data format. I think
it should be the platform that defines the content. Current
implementation doesn't have this flexibility. We have a design where
MSI mode uses message data to carry vector number info while MSI-X
mode uses message address to carry this info. Although it seems
strange, but I think it's allowed by the spec.

Thanks,
-Shawn.