[PATCH v1 0/7] gpu: nova-core: add INTR_CTRL interrupt controller and CPU doorbell self-test

[Joel Fernandes]

This series adds interrupt controller support to nova-core, and validates the
full interrupt path with a CPU-doorbell self-test. It is based on today's
drm-rust-next tree.

The GPU interrupt controller block (INTR_CTRL)
----------------------------------------------
INTR_CTRL is the GPU's two-level (top/leaf) interrupt controller. It
multiplexes all GSP and engine interrupts onto a single PCI MSI line. We need
it to receive asynchronous messages from GSP. GSP will the host with a SWGEN0
interrupt (routed via INTR_CTRL) to deliver async RPC messages like error
reports (XIDs) and other event.  INTR_CTRL also routes notifications from GPU
engines to PCIe MSI such as submitted work completion, MMU faults, etc.
Detailed documentation of the architecture with diagrams are provided in a
separate patch (patch 7/7).

What this series proves
-----------------------
The CPU doorbell self-test (patch 6/7) exercises the full interrupt path
end-to-end. It uses the LEAF_TRIGGER hardware register in INTR_CTRL to trigger
a interrupt, then waits for the IRQ handler to fire. The path under test is:

  LEAF_TRIGGER write
       v
  INTR_CTRL TOP/LEAF goes pending
       v
  GPU fires PCI MSI write
       v
  Host VFIO -> guest IOMMU/IRQ
       v
  Guest Linux IRQ -> nova-core handler
       v
  Handler

The full stack has been end-to-end tested on Ampere GA102 with GPU passthrough.

What comes next
---------------
This is the first stage. Once this lands, the next step is to read (via RPC)
the interrupt vector table that GSP programs at boot. That table tells us which
INTR_CTRL leaf and bit each engine is wired to, so the driver can route
incoming interrupts to per-engine handlers. Future patches will also add GSP interrupt
support, and a per-engine ISR dispatch loops.

The git tree with all patches can be found at:
git://git.kernel.org/pub/scm/linux/kernel/git/jfern/linux.git (tag: nova-intr-ctrl-v1-20260501b)

Joel Fernandes (7):
  rust: sync: completion: add wait_for_completion_timeout()
  gpu: nova-core: allocate PCI MSI vector during probe
  gpu: nova-core: add interrupt controller register definitions
  gpu: nova-core: add Architecture::is_pre_hopper() helper
  gpu: nova-core: add INTR_CTRL interrupt controller API
  gpu: nova-core: add CPU doorbell IRQ self-test
  gpu: nova-core: document INTR_CTRL interrupt tree

 Documentation/gpu/nova/core/intr-ctrl.rst  | 305 +++++++++++++++++++++
 Documentation/gpu/nova/index.rst           |   1 +
 drivers/gpu/nova-core/Kconfig              |  13 +
 drivers/gpu/nova-core/gpu.rs               |  22 ++
 drivers/gpu/nova-core/irq.rs               |  29 ++
 drivers/gpu/nova-core/irq/doorbell_test.rs | 203 ++++++++++++++
 drivers/gpu/nova-core/irq/intr_ctrl.rs     | 281 +++++++++++++++++++
 drivers/gpu/nova-core/nova_core.rs         |   2 +
 drivers/gpu/nova-core/regs.rs              |  13 +
 rust/kernel/sync/completion.rs             |  18 +-
 10 files changed, 886 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/gpu/nova/core/intr-ctrl.rst
 create mode 100644 drivers/gpu/nova-core/irq.rs
 create mode 100644 drivers/gpu/nova-core/irq/doorbell_test.rs
 create mode 100644 drivers/gpu/nova-core/irq/intr_ctrl.rs


base-commit: 610e892bdb57043c7769982c2bff0260b6007b75
-- 
2.34.1