From: Thierry Reding <treding@nvidia.com>
Date: Wed, 13 Dec 2017 12:25:14 +0100
Subject: drm/tegra: prime: Implement ->{begin,end}_cpu_access()
Git-commit: 27e92f1f1600c214bf649daddb9b88b68330a8d1
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

These callbacks allow the exporter to swap in and pin the backing
storage for buffers as well as invalidate the cache in preparation for
accessing the buffer from the CPU, and flush the cache and unpin the
backing storage when the CPU is done modifying the buffer.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/tegra/gem.c |   30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -568,6 +568,34 @@ static void tegra_gem_prime_release(stru
 	drm_gem_dmabuf_release(buf);
 }
 
+static int tegra_gem_prime_begin_cpu_access(struct dma_buf *buf,
+					    enum dma_data_direction direction)
+{
+	struct drm_gem_object *gem = buf->priv;
+	struct tegra_bo *bo = to_tegra_bo(gem);
+	struct drm_device *drm = gem->dev;
+
+	if (bo->pages)
+		dma_sync_sg_for_cpu(drm->dev, bo->sgt->sgl, bo->sgt->nents,
+				    DMA_FROM_DEVICE);
+
+	return 0;
+}
+
+static int tegra_gem_prime_end_cpu_access(struct dma_buf *buf,
+					  enum dma_data_direction direction)
+{
+	struct drm_gem_object *gem = buf->priv;
+	struct tegra_bo *bo = to_tegra_bo(gem);
+	struct drm_device *drm = gem->dev;
+
+	if (bo->pages)
+		dma_sync_sg_for_device(drm->dev, bo->sgt->sgl, bo->sgt->nents,
+				       DMA_TO_DEVICE);
+
+	return 0;
+}
+
 static void *tegra_gem_prime_kmap_atomic(struct dma_buf *buf,
 					 unsigned long page)
 {
@@ -618,6 +646,8 @@ static const struct dma_buf_ops tegra_ge
 	.map_dma_buf = tegra_gem_prime_map_dma_buf,
 	.unmap_dma_buf = tegra_gem_prime_unmap_dma_buf,
 	.release = tegra_gem_prime_release,
+	.begin_cpu_access = tegra_gem_prime_begin_cpu_access,
+	.end_cpu_access = tegra_gem_prime_end_cpu_access,
 	.map_atomic = tegra_gem_prime_kmap_atomic,
 	.unmap_atomic = tegra_gem_prime_kunmap_atomic,
 	.map = tegra_gem_prime_kmap,