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Commit e316f08f authored by Rob Herring's avatar Rob Herring
Browse files

drm/panfrost: Remove unnecessary mmu->lock mutex 



There's no need to serialize io-pgtable calls and the as_lock is
sufficient to serialize flush operations, so we can remove the per
page table lock.

Fixes: 7282f764 ("drm/panfrost: Implement per FD address spaces")
Suggested-by: default avatarRobin Murphy <robin.murphy@arm.com>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
Acked-by: default avatarAlyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: default avatarRobin Murphy <robin.murphy@arm.com>
Reviewed-by: default avatarSteven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190826223317.28509-4-robh@kernel.org
parent 330bec4b

drivers/gpu/drm/panfrost/panfrost_device.h

+0 −1
Original line number Diff line number Diff line
@@ -104,7 +104,6 @@ struct panfrost_device { 
struct panfrost_mmu {

	struct io_pgtable_cfg pgtbl_cfg;

	struct io_pgtable_ops *pgtbl_ops;

	struct mutex lock;

	int as;

	atomic_t as_count;

	struct list_head list;

drivers/gpu/drm/panfrost/panfrost_mmu.c

+0 −9
Original line number Diff line number Diff line
@@ -228,8 +228,6 @@ static int mmu_map_sg(struct panfrost_device *pfdev, struct panfrost_mmu *mmu, 
	struct io_pgtable_ops *ops = mmu->pgtbl_ops;

	u64 start_iova = iova;



	mutex_lock(&mmu->lock);



	for_each_sg(sgt->sgl, sgl, sgt->nents, count) {

		unsigned long paddr = sg_dma_address(sgl);

		size_t len = sg_dma_len(sgl);
@@ -249,8 +247,6 @@ static int mmu_map_sg(struct panfrost_device *pfdev, struct panfrost_mmu *mmu, 
	mmu_hw_do_operation(pfdev, mmu, start_iova, iova - start_iova,

			    AS_COMMAND_FLUSH_PT);



	mutex_unlock(&mmu->lock);



	return 0;

}
@@ -304,8 +300,6 @@ void panfrost_mmu_unmap(struct panfrost_gem_object *bo) 
	if (ret < 0)

		return;



	mutex_lock(&bo->mmu->lock);



	while (unmapped_len < len) {

		size_t unmapped_page;

		size_t pgsize = get_pgsize(iova, len - unmapped_len);
@@ -321,8 +315,6 @@ void panfrost_mmu_unmap(struct panfrost_gem_object *bo) 
	mmu_hw_do_operation(pfdev, bo->mmu, bo->node.start << PAGE_SHIFT,

			    bo->node.size << PAGE_SHIFT, AS_COMMAND_FLUSH_PT);



	mutex_unlock(&bo->mmu->lock);



	pm_runtime_mark_last_busy(pfdev->dev);

	pm_runtime_put_autosuspend(pfdev->dev);

	bo->is_mapped = false;
@@ -356,7 +348,6 @@ int panfrost_mmu_pgtable_alloc(struct panfrost_file_priv *priv) 
	struct panfrost_mmu *mmu = &priv->mmu;

	struct panfrost_device *pfdev = priv->pfdev;



	mutex_init(&mmu->lock);

	INIT_LIST_HEAD(&mmu->list);

	mmu->as = -1;