[PATCH v2 0/6] gpu: nova-core: gsp: add support for GMC messages

[Alexandre Courbot <acourbot@nvidia.com>]

This series contains patches 9 to 12 from John's r000 series v3 [1],
that add support for the GMC GSP message protocol. This code is rebased
on and adapted to the latest `drm-rust-next`, which clearly separates
the transport and message layers of the GSP command queue code. As a
result, this extracted series should be both smaller and easier to
review.

GMC is a new message type with its own header, used by the r000 firmware
for its boot protocol and newer interfaces.

No functional change is introduced by this series. The newly added code
remains dormant until the switch to r000 takes effect.

This series is based on `drm-rust-next`.

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

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
Changes in v2:
- Remove `Assisted-by: LLM` tags.
- Fix build with rustc 1.85. (Eliot)
- Mention that zero-length messages can be either for no reply or empty
  reply scenario. (Eliot)
- Do not use `super::` for imports when unneeded. (Eliot)
- Use `split_at_checked` for message parsing and factor out duplicate
  code between RPC and GMC into a helper. (Eliot)
- Remove `MessageFromGsp::COMMAND`. (Eliot)
- Add `const_assert`s to validate that messages do not cross the page
  boundary. (Eliot)
- Rename `is_reply_to` into `reply_status`. (Eliot)
- Fix stale doclink. (Eliot)
- Log unexpected responses instead of passing them to event handler. (Eliot)
- Change `await_msg_with` so it stops using `ENOMSG` as a control flow
  signal. (Eliot)
- Separate GSP-RM command failures from transport errors in the GMC
  reply path. (Eliot)
- Link to v1: https://patch.msgid.link/20261103-r000_rebase_on_cmdq-rpc-v1-0-189f9ff3bfd2@nvidia.com

Changes since John's v3:
- Rebase on top of `drm-rust-next`.
- Use same message type abstractions as the RPC message type.
- Simplify comments and code where relevant.
- Make `GmcApiHeader` wrap the bindings type instead of reproducing it.

---
Alexandre Courbot (2):
      gpu: nova-core: gsp: cmdq: move message trimming into its own function
      gpu: nova-core: gsp: cmdq: do not use ENOMSG to skip messages

John Hubbard (4):
      gpu: nova-core: gsp: fw: add the r000 bindings for the GMC API header
      gpu: nova-core: gsp: add the GMC API header
      gpu: nova-core: gsp: cmdq: add the GMC send path
      gpu: nova-core: gsp: cmdq: add the GMC receive path

 drivers/gpu/nova-core/gsp/cmdq.rs                |  51 ++-
 drivers/gpu/nova-core/gsp/cmdq/gmc.rs            | 434 +++++++++++++++++++++++
 drivers/gpu/nova-core/gsp/cmdq/rpc.rs            |  33 +-
 drivers/gpu/nova-core/gsp/fw.rs                  | 107 ++++++
 drivers/gpu/nova-core/gsp/fw/r000_00.rs          |  29 ++
 drivers/gpu/nova-core/gsp/fw/r000_00/bindings.rs | 110 ++++++
 6 files changed, 733 insertions(+), 31 deletions(-)
---
base-commit: 7a6bc132f1b51437063c9203e7221067b40a791e
change-id: 20261030-r000_rebase_on_cmdq-rpc-2990d9296a8f

Best regards,
--  
Alexandre Courbot <acourbot@nvidia.com>