Commit e322a484 authored by Karunika Choo's avatar Karunika Choo Committed by Steven Price
Browse files

drm/panthor: Serialize GPU cache flush operations 



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: default avatarLiviu Dudau <liviu.dudau@arm.com>
Co-developed-by: default avatarDennis Tsiang <dennis.tsiang@arm.com>
Signed-off-by: default avatarDennis Tsiang <dennis.tsiang@arm.com>
Signed-off-by: default avatarKarunika Choo <karunika.choo@arm.com>
Reviewed-by: default avatarSteven Price <steven.price@arm.com>
Signed-off-by: default avatarSteven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20250807162633.3666310-6-karunika.choo@arm.com
parent 3b1dc21d

drivers/gpu/drm/panthor/panthor_gpu.c

+7 −0
Original line number Diff line number Diff line
@@ -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)) {