[PATCH 0/3] drm/panthor: Misc MMU fixes/robustness improvements

[Boris Brezillon]

The first commit is fixing a bug we've seen on v13 HW. Even though
we don't quite understand what happens (race in the flush-elimination
logic when flush requests are sent concurrently from the CPU and the
MCU), it seems that the downstream driver has always been doing a
flush+invalidate of RW caches from the start, and that we were doing
so up until the atomic page table update changes, so let's go back to
that state and leave the RO L1 caches untouched.

The second patch a fix for a race that could very well happen if we
ever end up with a failure between the as_disable() and as_enable()
calls. We've not experienced this so far, but it seems worth plugging
the hole regardless. The last patch is a much more theoretical bug,
which would involve a buggy FW telling us that a CSG is suspended,
when it's actually. I've deliberately not added a Fixes tag on the
last one for this very reason, but I think it's worth staying on
the safe side by addressing this theoretical issue, still.

Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
---
Boris Brezillon (3):
      drm/panthor: Don't invalidate OTHER caches
      drm/panthor: Fully disable the AS even if it's going to be re-assigned
      drm/panthor: Move cache-flush after UPDATE(UNMAPPED)

 drivers/gpu/drm/panthor/panthor_mmu.c | 43 ++++++++++++++++-------------------
 1 file changed, 20 insertions(+), 23 deletions(-)
---
base-commit: 45585c3aa285854face65293acc95eff73063d6d
change-id: 20260924-panthor-mmu-fixes-a1832dc60908

Best regards,
--  
Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>