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SubjectRe: tracking of PCI address space
On Wed, Apr 08, 2009 at 03:53:55PM -0500, Kumar Gala wrote:
> I was wondering if we have anything that tracks regions associated with
> the "inbound" side of a pci_bus.
> What I mean is on embedded PPC we have window/mapping registers for both
> inbound (accessing memory on the SoC) and outbound (access PCI device
> MMIO, IO etc). The combination of the inbound & outbound convey what
> exists in the PCI address space vs CPU physical address space (and how to
> map from one to the other). Today in the PPC land we only attach
> outbound windows to the pci_bus. So technically the inbound side
> information (like what subset of physical memory is visible on the PCI
> bus) seems to be lost.

To the best of my knowledge there is no API to set inbound windows in
Linux. I've been implementing a virtio-over-PCI driver which needs the
inbound windows. I set them up myself during driver probe, using
get_immrbase() to get the IMMR registers. This board is a PCI Slave /
Agent, it doesn't even have PCI support compiled into the kernel.


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