On Tuesday 29 January 2013, Bjorn Helgaas wrote:

If you need this, it can be done in architecture code, can't it?  It's
true that there's nothing architecture-specific in this patch (other
than the fact that ARM is the only arch that needs it), but I'm not
sure there's anything useful for sharing here.

Since we're moving the host bridge code to drivers/pci/host now, I think
this code should live in the same place. It's entirely possible that
it will be shared between arch/arm and arch/arm64, although I would
hope that we can do away with the emulated bridge code entirely.

More generally speaking, this is infrastructure code, and for any
piece of infrastructure my rule is

* don't add platform specific infrastructure if it can be done at
  the architecture level
* don't add architecture specific infrastructure if it can be
  written in an architecture independent way
* don't add global infrastructure if you can use or extend the
  existing infrastructure.

In fact, it seems like what you're after is not so much an emulated
bridge that has no corresponding hardware, as it is a wrapper that
presents a standard PCIe interface to hardware that exists but doesn't
conform to the PCIe spec.  If you really do need to ultimately connect
this pci_sw_pci_bridge to a piece of hardware, that will certainly be
arch-specific.

As Jason Gunthorpe suggested, we might not need this at all, if the
Linux PCI code can be convinced not to need a configuration space
for the devices that in case of the Marvell hardware don't provide
one.

	Arnd