From: Thierry Reding <treding@xxxxxxxxxx>
Instead of going through the DMA mapping API for cache maintenance, use
the drm_clflush_*() family of functions to achieve the same effect.
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
---
drivers/gpu/drm/tegra/Kconfig | 1 +
drivers/gpu/drm/tegra/gem.c | 42 +++++++++++-------------------------------
2 files changed, 12 insertions(+), 31 deletions(-)
diff --git a/drivers/gpu/drm/tegra/Kconfig b/drivers/gpu/drm/tegra/Kconfig
index 74d9d621453d..4901f20f99a1 100644
--- a/drivers/gpu/drm/tegra/Kconfig
+++ b/drivers/gpu/drm/tegra/Kconfig
@@ -4,6 +4,7 @@ config DRM_TEGRA
depends on COMMON_CLK
depends on DRM
depends on RESET_CONTROLLER
+ select DRM_CACHE
select DRM_KMS_HELPER
select DRM_MIPI_DSI
select DRM_PANEL
diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index 499f86739786..11e97a46e63d 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -203,48 +203,28 @@ 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)
{
- 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 = bo->gem.size >> PAGE_SHIFT;
- sgt = drm_prime_pages_to_sg(bo->pages, bo->num_pages);
- if (IS_ERR(sgt))
- goto put_pages;
+ 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);
+ }
-#ifndef CONFIG_ARM64
/*
- * 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.
+ * Pages allocated by shmemfs are marked dirty but not flushed on
+ * ARMv7 and ARMv8. Since this memory is used to back framebuffers,
+ * however, they must be forced out of caches to avoid corruption
+ * on screen later on as the result of dirty cache-lines being
+ * flushed.
*/
- 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)
- goto release_sgt;
-#endif
-
- bo->sgt = sgt;
+ drm_clflush_sg(bo->sgt);
return 0;
-
-release_sgt:
- sg_free_table(sgt);
- kfree(sgt);
- sgt = ERR_PTR(-ENOMEM);
-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)
--
2.3.2
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