[PATCH v2 0/1] rust: pci: add a prerequisite for the r000 GSP firmware

[John Hubbard <jhubbard@nvidia.com>]

Here is a preparatory change for (or more accurately, from) the r000
GSP firmware series [1], which enables nova-core to work with the GSP
firmware for r615+ releases.

For the Rust PCI abstraction, add an accessor for the PCI domain
number. The patch stands on its own, so posting it now helps avoid
reviewing a huge-er r000 series. :)

This applies to today's drm-rust-next: commit 6e557330b874 ("gpu:
nova-core: factor out and expose Falcon::is_processor_suspended()")

Changes since v1 [2]:

* The helper takes a struct pci_bus pointer and only calls
  pci_domain_nr(), so that it is a transparent wrapper (Danilo). The v1
  helper took a struct pci_dev pointer, which broke the powerpc and
  s390 builds (Sashiko).

* The CAST comment is directly above the cast (Danilo).

* The CAST comment no longer cites pci_register_host_bridge(), which
  checks the domain only under CONFIG_PCI_DOMAINS_GENERIC.

* v2 has no Suggested-by tag, because Miguel suggested the
  debug_assert!() and not the accessor (Danilo).

* Patch 2/2 of v1 is in drm-rust-next, so v2 is a single patch.

An LLM coding assistant (Claude Code) helped write this patch, but I
have fussed over every line of both the code and the commit message.

Testing: booted nova-core on my 3-GPU test system (Turing, Ampere and
Blackwell GPUs) with all KUnit and built-in Nova tests enabled, as
usual.

[1] https://lore.kernel.org/all/20260918010719.1176945-1-jhubbard@nvidia.com/
[2] https://lore.kernel.org/all/20261110033655.148487-1-jhubbard@nvidia.com/


John Hubbard (1):
  rust: pci: add domain_nr() accessor

 rust/helpers/pci.c |  5 +++++
 rust/kernel/pci.rs | 16 ++++++++++++++++
 2 files changed, 21 insertions(+)


base-commit: 6e557330b874b0e1fdd03e8fe4c438f36c93eefa
-- 
2.56.1