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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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