drm/v3d: Wait for pending L2T flush before cleaning caches

v3d_clean_caches() starts the cache-clean sequence by writing
V3D_L2TCACTL_TMUWCF to V3D_CTL_L2TCACTL and then polling for that bit to
clear. It does not, however, check for an L2T flush (L2TFLS) that may
still be in flight from a previous operation.

On pre-V3D 7.1 hardware, kicking off the TMU write-combiner flush while an
L2T flush is still pending can clobber bits in L2TCACTL and cause cache
inconsistencies.

Poll for L2TFLS to clear before writing L2TCACTL on V3D < 7.1, ensuring
any pending flush has completed before a new clean is issued.

Cc: stable@vger.kernel.org
Fixes: d223f98f0209 ("drm/v3d: Add support for compute shader dispatch.")
Link: https://patch.msgid.link/20260530-v3d-fix-rpi4-freezes-v1-1-c2c8307da6ce@igalia.com
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>

0 files changed, 0 insertions, 0 deletions