Musings on PCI busses

[Arnd Bergmann]

On Tuesday 19 May 2009, Grant Likely wrote:
> 1) Probe the host controller in an of_platform driver.  This has the
> advantage of simplicity.  The probe routine will get automatically
> called when the PCI host controller device tree node is registered
> with the of_platform bus.  The bus parenthood also gets reflected in
> the device model and sysfs.  The disadvantage is that it defers PCI
> bus probing until after the of_platform bus is probed (maybe this is
> okay; maybe this already happens anyway).

This is also what we do on 64-bit systems (well, Cell at this time).
There are no fundamental problems with this, just some slightly
unexpected interactions e.g. when you have use a PCI serial port
as your console before probing PCI.

Making CONFIG_PPC_OF_PLATFORM_PCI probably requires some more
consolidation between pci_32.c and pci_64.c, but I'd consider
this a good thing.

	Arnd <><