On 07/08/2025 17:26, Karunika Choo wrote: > In certain scenarios, it is possible for multiple cache flushes to be > requested before the previous one completes. This patch introduces the > cache_flush_lock mutex to serialize these operations and ensure that > any requested cache flushes are completed instead of dropped. > > Reviewed-by: Liviu Dudau <[email protected]> > Co-developed-by: Dennis Tsiang <[email protected]> > Signed-off-by: Dennis Tsiang <[email protected]> > Signed-off-by: Karunika Choo <[email protected]>
Reviewed-by: Steven Price <[email protected]> > --- > drivers/gpu/drm/panthor/panthor_gpu.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/gpu/drm/panthor/panthor_gpu.c > b/drivers/gpu/drm/panthor/panthor_gpu.c > index 5e2c3173ae27..db69449a5be0 100644 > --- a/drivers/gpu/drm/panthor/panthor_gpu.c > +++ b/drivers/gpu/drm/panthor/panthor_gpu.c > @@ -35,6 +35,9 @@ struct panthor_gpu { > > /** @reqs_acked: GPU request wait queue. */ > wait_queue_head_t reqs_acked; > + > + /** @cache_flush_lock: Lock to serialize cache flushes */ > + struct mutex cache_flush_lock; > }; > > #define GPU_INTERRUPTS_MASK \ > @@ -110,6 +113,7 @@ int panthor_gpu_init(struct panthor_device *ptdev) > > spin_lock_init(&gpu->reqs_lock); > init_waitqueue_head(&gpu->reqs_acked); > + mutex_init(&gpu->cache_flush_lock); > ptdev->gpu = gpu; > > dma_set_max_seg_size(ptdev->base.dev, UINT_MAX); > @@ -258,6 +262,9 @@ int panthor_gpu_flush_caches(struct panthor_device *ptdev, > bool timedout = false; > unsigned long flags; > > + /* Serialize cache flush operations. */ > + guard(mutex)(&ptdev->gpu->cache_flush_lock); > + > spin_lock_irqsave(&ptdev->gpu->reqs_lock, flags); > if (!drm_WARN_ON(&ptdev->base, > ptdev->gpu->pending_reqs & > GPU_IRQ_CLEAN_CACHES_COMPLETED)) {
