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Subject: Re: [RFC PATCH 00/35] Move all PCIBIOS* definitions into arch/x86
From:   Benjamin Herrenschmidt <benh@kernel.crashing.org>
To:     Kjetil Oftedal <oftedal@gmail.com>,
        Bjorn Helgaas <helgaas@kernel.org>
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Date:   Wed, 15 Jul 2020 12:14:09 +1000
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On Tue, 2020-07-14 at 23:02 +0200, Kjetil Oftedal wrote:
> > 
> > > For b), it might be nice to also change other aspects of the
> > > interface, e.g. passing a pci_host_bridge pointer plus bus number
> > > instead of a pci_bus pointer, or having the callback in the
> > > pci_host_bridge structure.
> > 
> > I like this idea a lot, too.  I think the fact that
> > pci_bus_read_config_word() requires a pci_bus * complicates things in
> > a few places.
> > 
> > I think it's completely separate, as you say, and we should defer it
> > for now because even part a) is a lot of work.  I added it to my list
> > of possible future projects.
> > 
> 
> What about strange PCI devices such as Non-Transparent bridges?
> They will require their own PCI Config space accessors that is not
> connected to a host bridge if one wants to do some sort of
> punch-through enumeration.
> I guess the kernel doesn't care much about them?

Well, today they would require a pci_bus anyway.. . so if you want to do
that sort of funny trick you may as well create a "virtual" host bridge.

Cheers,
Ben.