drm/xe/pxp: add termination on resume

drm/xe/pxp: add termination on resume

Suspend/resume causes the PXP keys to become invalid, but doesn't
actually kill the session. The driver also doesn't explicitly kill and
re-start the session until a new PXP request comes in, which means that
the "zombie" session can potentially stick around if there are no new
requests from userspace. While this is not an issue for PXP, HDCP has a
new behavior starting on PTL where a communication is sent to GSC if a
session is active at suspend time (even if it doesn't have a valid key),
which can lead to delays in the suspend flow if we suspend while the
zombie session is still active.
To avoid this, we can trigger a termination on resume and kill the
zombie session immediately, instead of delaying the termination to the
next PXP request. Due to restrictions in the rpm suspend/resume flow, we
can't call the termination flow from within the resume call itself, so
the pxp irq worker is expanded to cover this scenario.
The existing logic in the worker doesn't work as-is for the new flow,
because the pm_get_if_active will fail if the worker runs before the
pci_resume call has completed (which is possible, since we queue it
from within that call) or after we're started to suspend again.
Given that we always want to run the worker after a resume (differently
from the irq case, where we want to skip if we're suspended), we can
solve this by just taking the PM reference before queueing the worker.
As part of this rework, the pxp->events variable has been moved to atomic,
to avoid having to take xe->irq.lock from non-irq related paths.

Fixes: b1dcec9bd8a1 ("drm/xe/ptl: Enable PXP for PTL")
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Julia Filipchuk <julia.filipchuk@intel.com>
Cc: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Link: https://patch.msgid.link/20260720222757.3876338-2-daniele.ceraolospurio@intel.com
(cherry picked from commit 757bda2b8b93fa36ad9b2c7993081d5f9d0d6e3b)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>