From a04251fc94b58ec25476e57986dfec727b812c22 Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Tue, 16 Dec 2014 16:35:26 +0100 Subject: drm/tegra: gem: Flush buffer objects upon allocation Buffers obtained via shmem may still have associated cachelines. If they aren't properly flushed they may cause framebuffer corruption if the cache gets flushed after the application has drawn to it. Signed-off-by: Thierry Reding --- drivers/gpu/drm/tegra/gem.c | 36 ++++++++++++++++++++++++++++++++---- 1 file changed, 32 insertions(+), 4 deletions(-) (limited to 'drivers/gpu/drm/tegra/gem.c') diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c index da32086cbeaf..c888bed4036f 100644 --- a/drivers/gpu/drm/tegra/gem.c +++ b/drivers/gpu/drm/tegra/gem.c @@ -219,19 +219,47 @@ static void tegra_bo_free(struct drm_device *drm, struct tegra_bo *bo) static int tegra_bo_get_pages(struct drm_device *drm, struct tegra_bo *bo, size_t size) { + struct scatterlist *s; + struct sg_table *sgt; + unsigned int i; + bo->pages = drm_gem_get_pages(&bo->gem); if (IS_ERR(bo->pages)) return PTR_ERR(bo->pages); bo->num_pages = size >> PAGE_SHIFT; - bo->sgt = drm_prime_pages_to_sg(bo->pages, bo->num_pages); - if (IS_ERR(bo->sgt)) { - drm_gem_put_pages(&bo->gem, bo->pages, false, false); - return PTR_ERR(bo->sgt); + sgt = drm_prime_pages_to_sg(bo->pages, bo->num_pages); + if (IS_ERR(sgt)) + goto put_pages; + + /* + * Fake up the SG table so that dma_map_sg() can be used to flush the + * pages associated with it. Note that this relies on the fact that + * the DMA API doesn't hook into IOMMU on Tegra, therefore mapping is + * only cache maintenance. + * + * TODO: Replace this by drm_clflash_sg() once it can be implemented + * without relying on symbols that are not exported. + */ + for_each_sg(sgt->sgl, s, sgt->nents, i) + sg_dma_address(s) = sg_phys(s); + + if (dma_map_sg(drm->dev, sgt->sgl, sgt->nents, DMA_TO_DEVICE) == 0) { + sgt = ERR_PTR(-ENOMEM); + goto release_sgt; } + bo->sgt = sgt; + return 0; + +release_sgt: + sg_free_table(sgt); + kfree(sgt); +put_pages: + drm_gem_put_pages(&bo->gem, bo->pages, false, false); + return PTR_ERR(sgt); } static int tegra_bo_alloc(struct drm_device *drm, struct tegra_bo *bo, -- cgit v1.2.3 From 73c42c79767a03ae64d11457e3ce80e80e09e514 Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Tue, 16 Dec 2014 16:41:47 +0100 Subject: drm/tegra: gem: Use the proper size for GEM objects If the requested buffer size wasn't a multiple of the page size, the IOMMU code would round down the size to the next multiple of the page size, thereby causing translation errors. To fix this we no longer pass around the requested size but reuse the computed size of the GEM object. This is already rounded to the next page boundary, so mapping that size works out fine. Signed-off-by: Thierry Reding --- drivers/gpu/drm/tegra/gem.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'drivers/gpu/drm/tegra/gem.c') diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c index c888bed4036f..8777b7f75791 100644 --- a/drivers/gpu/drm/tegra/gem.c +++ b/drivers/gpu/drm/tegra/gem.c @@ -216,8 +216,7 @@ static void tegra_bo_free(struct drm_device *drm, struct tegra_bo *bo) } } -static int tegra_bo_get_pages(struct drm_device *drm, struct tegra_bo *bo, - size_t size) +static int tegra_bo_get_pages(struct drm_device *drm, struct tegra_bo *bo) { struct scatterlist *s; struct sg_table *sgt; @@ -227,7 +226,7 @@ static int tegra_bo_get_pages(struct drm_device *drm, struct tegra_bo *bo, if (IS_ERR(bo->pages)) return PTR_ERR(bo->pages); - bo->num_pages = size >> PAGE_SHIFT; + bo->num_pages = bo->gem.size >> PAGE_SHIFT; sgt = drm_prime_pages_to_sg(bo->pages, bo->num_pages); if (IS_ERR(sgt)) @@ -262,14 +261,13 @@ put_pages: return PTR_ERR(sgt); } -static int tegra_bo_alloc(struct drm_device *drm, struct tegra_bo *bo, - size_t size) +static int tegra_bo_alloc(struct drm_device *drm, struct tegra_bo *bo) { struct tegra_drm *tegra = drm->dev_private; int err; if (tegra->domain) { - err = tegra_bo_get_pages(drm, bo, size); + err = tegra_bo_get_pages(drm, bo); if (err < 0) return err; @@ -279,6 +277,8 @@ static int tegra_bo_alloc(struct drm_device *drm, struct tegra_bo *bo, return err; } } else { + size_t size = bo->gem.size; + bo->vaddr = dma_alloc_writecombine(drm->dev, size, &bo->paddr, GFP_KERNEL | __GFP_NOWARN); if (!bo->vaddr) { @@ -302,7 +302,7 @@ struct tegra_bo *tegra_bo_create(struct drm_device *drm, size_t size, if (IS_ERR(bo)) return bo; - err = tegra_bo_alloc(drm, bo, size); + err = tegra_bo_alloc(drm, bo); if (err < 0) goto release; -- cgit v1.2.3