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

[Arnd Bergmann]

On Sat, Mar 20, 2021 at 2:23 PM Marc Zyngier <maz@xxxxxxxxxx> wrote:
>
> On Sat, 20 Mar 2021 13:03:13 +0000,
> Arnd Bergmann <arnd@xxxxxxxx> wrote:
> >
> > On Sat, Mar 20, 2021 at 1:54 PM Marc Zyngier <maz@xxxxxxxxxx> wrote:
> > > On Fri, 19 Mar 2021 21:12:46 +0000,
> > >
> > > Having an optional callback to host bridges to obtain the MSI domain
> > > may be possible in some cases though (there might be a chicken/egg
> > > problem for some drivers though...).
> >
> > I would expect that the host bridge driver can find the MSI domain
> > at probe time and just add a pointer into the pci_host_bridge
> > structure.
>
> In most cases, it doesn't implement it itself, and I'd be reluctant to
> duplicate information that can already be retrieved from somewhere
> else in a generic way (i.e. no PCI specific).

At the moment, the information is retried through a maze of different
functions, and already duplicated in both the pci_host_bridge and the
pci_bus structures.  If we can change everything to use
CONFIG_GENERIC_MSI_IRQ_DOMAIN, then most of that code
can probably just go away, leaving only the part in the phb.

       Arnd