+/* prepare the sg table with the user pages */
+static int radeon_ttm_tt_pin_userptr(struct ttm_tt *ttm)
+{
+ struct radeon_device *rdev = radeon_get_rdev(ttm->bdev);
+ struct radeon_ttm_tt *gtt = (void *)ttm;
+ unsigned pinned = 0, nents;
+ int r;
+
+ int write = !(gtt->userflags & RADEON_GEM_USERPTR_READONLY);
+ enum dma_data_direction direction = write ?
+ DMA_BIDIRECTIONAL : DMA_TO_DEVICE;
+
+ if (current->mm != gtt->usermm)
+ return -EPERM;
+
+ do {
+ unsigned num_pages = ttm->num_pages - pinned;
+ uint64_t userptr = gtt->userptr + pinned * PAGE_SIZE;
+ struct page **pages = ttm->pages + pinned;
+
+ r = get_user_pages(current, current->mm, userptr, num_pages,
+ write, 0, pages, NULL);
+ if (r < 0)
+ goto release_pages;
+
+ pinned += r;
+
+ } while (pinned < ttm->num_pages);
+
+ r = sg_alloc_table_from_pages(ttm->sg, ttm->pages, ttm->num_pages, 0,
+ ttm->num_pages << PAGE_SHIFT,
+ GFP_KERNEL);
+ if (r)
+ goto release_sg;
+
+ r = -ENOMEM;
+ nents = dma_map_sg(rdev->dev, ttm->sg->sgl, ttm->sg->nents, direction);
+ if (nents != ttm->sg->nents)
+ goto release_sg;
+
+ drm_prime_sg_to_page_addr_arrays(ttm->sg, ttm->pages,
+ gtt->ttm.dma_address, ttm->num_pages);
+
+ return 0;
+
+release_sg:
+ kfree(ttm->sg);
+
+release_pages:
+ release_pages(ttm->pages, pinned, 0);
+ return r;
+}
+
+static void radeon_ttm_tt_unpin_userptr(struct ttm_tt *ttm)
+{
+ struct radeon_device *rdev = radeon_get_rdev(ttm->bdev);
+ struct radeon_ttm_tt *gtt = (void *)ttm;
+ struct scatterlist *sg;
+ int i;
+
+ int write = !(gtt->userflags & RADEON_GEM_USERPTR_READONLY);
+ enum dma_data_direction direction = write ?
+ DMA_BIDIRECTIONAL : DMA_TO_DEVICE;
+
+ /* free the sg table and pages again */
+ dma_unmap_sg(rdev->dev, ttm->sg->sgl, ttm->sg->nents, direction);
+
+ for_each_sg(ttm->sg->sgl, sg, ttm->sg->nents, i) {
+ struct page *page = sg_page(sg);
+
+ if (!(gtt->userflags & RADEON_GEM_USERPTR_READONLY))
+ set_page_dirty(page);
+
+ mark_page_accessed(page);
+ page_cache_release(page);
+ }
+
+ sg_free_table(ttm->sg);
+}
+