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

On Sat, Mar 20, 2021 at 2:23 PM Marc Zyngier [off-list ref] wrote:

On Sat, 20 Mar 2021 13:03:13 +0000,
Arnd Bergmann [off-list ref] wrote:

quoted

On Sat, Mar 20, 2021 at 1:54 PM Marc Zyngier [off-list ref] wrote:

quoted

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