[RFC/RFT PATCH 03/18] PCI: Introduce pci_scan_root_bus_bridge()

[Arnd Bergmann]

On Tue, May 2, 2017 at 7:15 PM, Lorenzo Pieralisi
<lorenzo.pieralisi at arm.com> wrote:
> On Fri, Apr 28, 2017 at 02:28:38PM +0200, Arnd Bergmann wrote:
>> On Wed, Apr 26, 2017 at 1:17 PM, Lorenzo Pieralisi
>> <lorenzo.pieralisi at arm.com> wrote:
>>
>> Good idea, yes. To avoid growing the number of interfaces too
>> much, should we change the existing users of pci_register_host_bridge
>> in host drivers over to this entry point, and make the other one
>> local to probe.c then?
>
> Yes, the problem is that there are drivers (ie pcie-iproc.c) that
> require the struct pci_bus (created by pci_register_host_bridge())
> to fiddle with it to check link status and THEN scan the bus (so
> the pci_register_host_bridge() call can't be embedded in the scan
> interface - the driver requires struct pci_bus for pci_ops to work
> before scanning the bus itself).
>
> I will see how I can accommodate this change because you definitely
> have a point.

The obvious answer for that particular problem would be a link_check()
callback in the bridge operations. I think that would also fit in well with
the dw_pcie driver that has some private infrastructure for it. I don't
know if that callback is sufficient to solve all related problems though.

       Arnd