Re: [PATCH v3 05/12] PCI: of_property: Assign PCI instead of CPU bus address to dynamic bridge nodes

Bjorn Helgaas
2024-11-04T23:49:39Z

On Mon, Nov 04, 2024 at 08:35:21PM +0530, Manivannan Sadhasivam wrote:
> On Mon, Nov 04, 2024 at 09:54:57AM +0100, Andrea della Porta wrote:
> > On 22:39 Sat 02 Nov , Manivannan Sadhasivam wrote:
> > > On Mon, Oct 28, 2024 at 03:07:22PM +0100, Andrea della Porta wrote:
> > > > When populating "ranges" property for a PCI bridge, of_pci_prop_ranges()
> > > > incorrectly use the CPU bus address of the resource. Since this is a PCI-PCI
> > > > bridge, the window should instead be in PCI address space. Call
> > > > pci_bus_address() on the resource in order to obtain the PCI bus
> > > > address.
> > >
> > > of_pci_prop_ranges() could be called for PCI devices also (not just PCI
> > > bridges), right?
> >
> > Correct. Please note however that while the PCI-PCI bridge has the parent
> > address in CPU space, an endpoint device has it in PCI space: here we're
> > focusing on the bridge part. It probably used to work before since in many
> > cases the CPU and PCI address are the same, but it breaks down when they
> > differ.
>
> When you say 'focusing', you are specifically referring to the
> bridge part of this API I believe. But I don't see a check for the
> bridge in your change, which is what concerning me. Am I missing
> something?

I think we want this change for all devices in the PCI address
domain, including PCI-PCI bridges and endpoints, don't we? All those
"ranges" addresses should be in the PCI domain.

Bjorn