Re: [RFC 1/2] arm64: PCI: Allow use arch-specific pci sysdata

[Boqun Feng]

Hi Arnd,

On Sat, Mar 20, 2021 at 05:09:10PM +0100, Arnd Bergmann wrote:
> On Sat, Mar 20, 2021 at 1:54 PM Arnd Bergmann <arnd@xxxxxxxx> wrote:
> >      I actually still have a (not really tested) patch series to clean up
> > the pci host bridge registration, and this should make this a lot easier
> > to add on top.
> >
> > I should dig that out of my backlog and post for review.
> 
> I've uploaded my series to
> https://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground.git
> pci-probe-rework-20210320
> 
> The purpose of this series is mostly to simplify what variations of
> host probe methods exist, towards using pci_host_probe() as the
> only method. It does provide some simplifications based on that
> that, including a way to universally have access to the pci_host_bridge
> pointer during the probe function.
> 

Thanks for the suggestion and code. I spend some time to catch up. Yes,
Bjorn and you are correct, the better way is having a 'domain_nr' in the
'pci_host_bridge' and making sure every driver fill that correctly
before probe. I definitly will use this approach.

However, I may start small: I plan to introduce 'domain_nr' and only
fill the field at probe time for PCI_DOMAINS_GENERIC=y archs, and leave
other archs and driver alone. (honestly, I was shocked by the number of
pci_scan_root_bus_bridge() and pci_host_probe() that I need to adjust if
I really want to unify the 'domain_nr' handling for every arch and
driver ;-)). This will fulfil my requirement for Hyper-V PCI controller
on ARM64. And later on, we can switch each arch to this approach one by
one and keep the rest still working.

Thoughts?

Regards,
Boqun

>          Arnd