gpu: nova-core: service GSP events from the SWGEN0 interrupt

The GSP posts each message for the CPU to the GSP-to-CPU queue and then
raises SWGEN0, a software-generated interrupt cause of its falcon. GIN
delivers SWGEN0 to the CPU on vector 155.

A thread waiting for a command reply was the only reader of the queue,
so an event posted between commands stayed unread until the next
command was sent.

Register a threaded handler on the GSP vector. Draining the queue takes
the command-queue mutex, which can sleep, so the top half reads and
writes only registers and wakes the IRQ thread to drain the queue.
Every existing read of the queue asks for one message type and waits on
a deadline, so add a drain that logs and consumes whatever the GSP has
already posted and returns at once.

When a falcon cause other than SWGEN0 stays set after its latch is
cleared, as the Blackwell fault-containment and ECC causes do, disable
the GSP vector rather than retrigger the falcon. A retrigger would
re-emit the cause at once, and the CPU would take the same interrupt
again and again.

Assisted-by: LLM
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://patch.msgid.link/20260930034148.590687-14-jhubbard@nvidia.com
[acourbot: trim comment leaking unneeded implementation details.]
[acourbot: make Subtree crate-visible here instead of in earlier patch.]
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>

0 files changed, 0 insertions, 0 deletions