drm/tegra: prime: Implement ->{begin,end}_cpu_access()

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>

diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index 8fc5860ab19a0a49743714f5d279a234c3c8d1df..8b0b4ff64bb41a812468af38518a266e4ac945db 100644 (file)
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -568,6 +568,34 @@ static void tegra_gem_prime_release(struct dma_buf *buf)
        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_gem_prime_dmabuf_ops = {
        .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,