Pull fwctl updates from Jason Gunthorpe:

 - Support more commands in bnxt, this completes what they originally
   wanted to do

 - Rust bindings for fwctl. The Nova GPU is expected to use them next
   cycle

* tag 'for-linus-fwctl' of git://git.kernel.org/pub/scm/linux/kernel/git/fwctl/fwctl:
  rust: introduce abstractions for fwctl
  fwctl/bnxt: Add DMA buffer support for HWRM commands
  bnxt_en: Update bnxt firmware spec

Introduce safe Rust wrappers around struct fwctl_device and struct
fwctl_uctx. This lets Rust drivers register fwctl devices and implement
firmware RPC callbacks through a typed trait interface.

The abstraction keeps lifetime and reference-count handling inside the
wrapper, exposes pinned per-FD user contexts to drivers, and validates the
layout assumptions required by the C fwctl allocation model. Allocation
sizes are padded so the kmalloc-backed C allocations also satisfy Rust
alignment requirements.

Registration owns driver private data with a lifetime tied to the bound
parent device and verifies the parent identity before registration.
Callbacks access that data through a higher-ranked closure, preventing its
erased lifetime from escaping, while Device remains only the refcounted
fwctl object. This avoids requiring Rust drop glue from the fwctl_device
release path after unregister or module teardown.

RPC callbacks receive typed scope information, a mutable request/response
buffer, and the userspace output-buffer size. Response pointer conversion,
length validation, and raw output-length handling remain inside the
abstraction.

Add the Rust sources to the FWCTL MAINTAINERS entry and add myself as the
maintainer for the Rust abstractions.

Link: https://patch.msgid.link/r/20260813152312.1311142-2-zhiw@nvidia.com
Co-developed-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Zhi Wang <zhiw@nvidia.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>