1 files changed, 653 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
new file mode 100644
index 000000000000..4c087c1510d7
--- /dev/null
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -0,0 +1,653 @@
+/*
+ * Copyright 2009 Jerome Glisse.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ */
+/*
+ * Authors:
+ *    Jerome Glisse <glisse@freedesktop.org>
+ *    Thomas Hellstrom <thomas-at-tungstengraphics-dot-com>
+ *    Dave Airlie
+ */
+#include <ttm/ttm_bo_api.h>
+#include <ttm/ttm_bo_driver.h>
+#include <ttm/ttm_placement.h>
+#include <ttm/ttm_module.h>
+#include <drm/drmP.h>
+#include <drm/radeon_drm.h>
+#include "radeon_reg.h"
+#include "radeon.h"
+
+#define DRM_FILE_PAGE_OFFSET (0x100000000ULL >> PAGE_SHIFT)
+
+static struct radeon_device *radeon_get_rdev(struct ttm_bo_device *bdev)
+{
+	struct radeon_mman *mman;
+	struct radeon_device *rdev;
+
+	mman = container_of(bdev, struct radeon_mman, bdev);
+	rdev = container_of(mman, struct radeon_device, mman);
+	return rdev;
+}
+
+
+/*
+ * Global memory.
+ */
+static int radeon_ttm_mem_global_init(struct ttm_global_reference *ref)
+{
+	return ttm_mem_global_init(ref->object);
+}
+
+static void radeon_ttm_mem_global_release(struct ttm_global_reference *ref)
+{
+	ttm_mem_global_release(ref->object);
+}
+
+static int radeon_ttm_global_init(struct radeon_device *rdev)
+{
+	struct ttm_global_reference *global_ref;
+	int r;
+
+	rdev->mman.mem_global_referenced = false;
+	global_ref = &rdev->mman.mem_global_ref;
+	global_ref->global_type = TTM_GLOBAL_TTM_MEM;
+	global_ref->size = sizeof(struct ttm_mem_global);
+	global_ref->init = &radeon_ttm_mem_global_init;
+	global_ref->release = &radeon_ttm_mem_global_release;
+	r = ttm_global_item_ref(global_ref);
+	if (r != 0) {
+		DRM_ERROR("Failed referencing a global TTM memory object.\n");
+		return r;
+	}
+	rdev->mman.mem_global_referenced = true;
+	return 0;
+}
+
+static void radeon_ttm_global_fini(struct radeon_device *rdev)
+{
+	if (rdev->mman.mem_global_referenced) {
+		ttm_global_item_unref(&rdev->mman.mem_global_ref);
+		rdev->mman.mem_global_referenced = false;
+	}
+}
+
+struct ttm_backend *radeon_ttm_backend_create(struct radeon_device *rdev);
+
+static struct ttm_backend*
+radeon_create_ttm_backend_entry(struct ttm_bo_device *bdev)
+{
+	struct radeon_device *rdev;
+
+	rdev = radeon_get_rdev(bdev);
+#if __OS_HAS_AGP
+	if (rdev->flags & RADEON_IS_AGP) {
+		return ttm_agp_backend_init(bdev, rdev->ddev->agp->bridge);
+	} else
+#endif
+	{
+		return radeon_ttm_backend_create(rdev);
+	}
+}
+
+static int radeon_invalidate_caches(struct ttm_bo_device *bdev, uint32_t flags)
+{
+	return 0;
+}
+
+static int radeon_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
+				struct ttm_mem_type_manager *man)
+{
+	struct radeon_device *rdev;
+
+	rdev = radeon_get_rdev(bdev);
+
+	switch (type) {
+	case TTM_PL_SYSTEM:
+		/* System memory */
+		man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
+		man->available_caching = TTM_PL_MASK_CACHING;
+		man->default_caching = TTM_PL_FLAG_CACHED;
+		break;
+	case TTM_PL_TT:
+		man->gpu_offset = 0;
+		man->available_caching = TTM_PL_MASK_CACHING;
+		man->default_caching = TTM_PL_FLAG_CACHED;
+#if __OS_HAS_AGP
+		if (rdev->flags & RADEON_IS_AGP) {
+			if (!(drm_core_has_AGP(rdev->ddev) && rdev->ddev->agp)) {
+				DRM_ERROR("AGP is not enabled for memory type %u\n",
+					  (unsigned)type);
+				return -EINVAL;
+			}
+			man->io_offset = rdev->mc.agp_base;
+			man->io_size = rdev->mc.gtt_size;
+			man->io_addr = NULL;
+			man->flags = TTM_MEMTYPE_FLAG_NEEDS_IOREMAP |
+				     TTM_MEMTYPE_FLAG_MAPPABLE;
+			man->available_caching = TTM_PL_FLAG_UNCACHED |
+						 TTM_PL_FLAG_WC;
+			man->default_caching = TTM_PL_FLAG_WC;
+		} else
+#endif
+		{
+			man->io_offset = 0;
+			man->io_size = 0;
+			man->io_addr = NULL;
+			man->flags = TTM_MEMTYPE_FLAG_MAPPABLE |
+				     TTM_MEMTYPE_FLAG_CMA;
+		}
+		break;
+	case TTM_PL_VRAM:
+		/* "On-card" video ram */
+		man->gpu_offset = 0;
+		man->flags = TTM_MEMTYPE_FLAG_FIXED |
+			     TTM_MEMTYPE_FLAG_NEEDS_IOREMAP |
+			     TTM_MEMTYPE_FLAG_MAPPABLE;
+		man->available_caching = TTM_PL_FLAG_UNCACHED | TTM_PL_FLAG_WC;
+		man->default_caching = TTM_PL_FLAG_WC;
+		man->io_addr = NULL;
+		man->io_offset = rdev->mc.aper_base;
+		man->io_size = rdev->mc.aper_size;
+		break;
+	default:
+		DRM_ERROR("Unsupported memory type %u\n", (unsigned)type);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static uint32_t radeon_evict_flags(struct ttm_buffer_object *bo)
+{
+	uint32_t cur_placement = bo->mem.placement & ~TTM_PL_MASK_MEMTYPE;
+
+	switch (bo->mem.mem_type) {
+	default:
+		return (cur_placement & ~TTM_PL_MASK_CACHING) |
+			TTM_PL_FLAG_SYSTEM |
+			TTM_PL_FLAG_CACHED;
+	}
+}
+
+static int radeon_verify_access(struct ttm_buffer_object *bo, struct file *filp)
+{
+	return 0;
+}
+
+static void radeon_move_null(struct ttm_buffer_object *bo,
+			     struct ttm_mem_reg *new_mem)
+{
+	struct ttm_mem_reg *old_mem = &bo->mem;
+
+	BUG_ON(old_mem->mm_node != NULL);
+	*old_mem = *new_mem;
+	new_mem->mm_node = NULL;
+}
+
+static int radeon_move_blit(struct ttm_buffer_object *bo,
+			    bool evict, int no_wait,
+			    struct ttm_mem_reg *new_mem,
+			    struct ttm_mem_reg *old_mem)
+{
+	struct radeon_device *rdev;
+	uint64_t old_start, new_start;
+	struct radeon_fence *fence;
+	int r;
+
+	rdev = radeon_get_rdev(bo->bdev);
+	r = radeon_fence_create(rdev, &fence);
+	if (unlikely(r)) {
+		return r;
+	}
+	old_start = old_mem->mm_node->start << PAGE_SHIFT;
+	new_start = new_mem->mm_node->start << PAGE_SHIFT;
+
+	switch (old_mem->mem_type) {
+	case TTM_PL_VRAM:
+		old_start += rdev->mc.vram_location;
+		break;
+	case TTM_PL_TT:
+		old_start += rdev->mc.gtt_location;
+		break;
+	default:
+		DRM_ERROR("Unknown placement %d\n", old_mem->mem_type);
+		return -EINVAL;
+	}
+	switch (new_mem->mem_type) {
+	case TTM_PL_VRAM:
+		new_start += rdev->mc.vram_location;
+		break;
+	case TTM_PL_TT:
+		new_start += rdev->mc.gtt_location;
+		break;
+	default:
+		DRM_ERROR("Unknown placement %d\n", old_mem->mem_type);
+		return -EINVAL;
+	}
+	if (!rdev->cp.ready) {
+		DRM_ERROR("Trying to move memory with CP turned off.\n");
+		return -EINVAL;
+	}
+	r = radeon_copy(rdev, old_start, new_start, new_mem->num_pages, fence);
+	/* FIXME: handle copy error */
+	r = ttm_bo_move_accel_cleanup(bo, (void *)fence, NULL,
+				      evict, no_wait, new_mem);
+	radeon_fence_unref(&fence);
+	return r;
+}
+
+static int radeon_move_vram_ram(struct ttm_buffer_object *bo,
+				bool evict, bool interruptible, bool no_wait,
+				struct ttm_mem_reg *new_mem)
+{
+	struct radeon_device *rdev;
+	struct ttm_mem_reg *old_mem = &bo->mem;
+	struct ttm_mem_reg tmp_mem;
+	uint32_t proposed_placement;
+	int r;
+
+	rdev = radeon_get_rdev(bo->bdev);
+	tmp_mem = *new_mem;
+	tmp_mem.mm_node = NULL;
+	proposed_placement = TTM_PL_FLAG_TT | TTM_PL_MASK_CACHING;
+	r = ttm_bo_mem_space(bo, proposed_placement, &tmp_mem,
+			     interruptible, no_wait);
+	if (unlikely(r)) {
+		return r;
+	}
+	r = ttm_tt_bind(bo->ttm, &tmp_mem);
+	if (unlikely(r)) {
+		goto out_cleanup;
+	}
+	r = radeon_move_blit(bo, true, no_wait, &tmp_mem, old_mem);
+	if (unlikely(r)) {
+		goto out_cleanup;
+	}
+	r = ttm_bo_move_ttm(bo, true, no_wait, new_mem);
+out_cleanup:
+	if (tmp_mem.mm_node) {
+		spin_lock(&rdev->mman.bdev.lru_lock);
+		drm_mm_put_block(tmp_mem.mm_node);
+		spin_unlock(&rdev->mman.bdev.lru_lock);
+		return r;
+	}
+	return r;
+}
+
+static int radeon_move_ram_vram(struct ttm_buffer_object *bo,
+				bool evict, bool interruptible, bool no_wait,
+				struct ttm_mem_reg *new_mem)
+{
+	struct radeon_device *rdev;
+	struct ttm_mem_reg *old_mem = &bo->mem;
+	struct ttm_mem_reg tmp_mem;
+	uint32_t proposed_flags;
+	int r;
+
+	rdev = radeon_get_rdev(bo->bdev);
+	tmp_mem = *new_mem;
+	tmp_mem.mm_node = NULL;
+	proposed_flags = TTM_PL_FLAG_TT | TTM_PL_MASK_CACHING;
+	r = ttm_bo_mem_space(bo, proposed_flags, &tmp_mem,
+			     interruptible, no_wait);
+	if (unlikely(r)) {
+		return r;
+	}
+	r = ttm_bo_move_ttm(bo, true, no_wait, &tmp_mem);
+	if (unlikely(r)) {
+		goto out_cleanup;
+	}
+	r = radeon_move_blit(bo, true, no_wait, new_mem, old_mem);
+	if (unlikely(r)) {
+		goto out_cleanup;
+	}
+out_cleanup:
+	if (tmp_mem.mm_node) {
+		spin_lock(&rdev->mman.bdev.lru_lock);
+		drm_mm_put_block(tmp_mem.mm_node);
+		spin_unlock(&rdev->mman.bdev.lru_lock);
+		return r;
+	}
+	return r;
+}
+
+static int radeon_bo_move(struct ttm_buffer_object *bo,
+			  bool evict, bool interruptible, bool no_wait,
+			  struct ttm_mem_reg *new_mem)
+{
+	struct radeon_device *rdev;
+	struct ttm_mem_reg *old_mem = &bo->mem;
+	int r;
+
+	rdev = radeon_get_rdev(bo->bdev);
+	if (old_mem->mem_type == TTM_PL_SYSTEM && bo->ttm == NULL) {
+		radeon_move_null(bo, new_mem);
+		return 0;
+	}
+	if ((old_mem->mem_type == TTM_PL_TT &&
+	     new_mem->mem_type == TTM_PL_SYSTEM) ||
+	    (old_mem->mem_type == TTM_PL_SYSTEM &&
+	     new_mem->mem_type == TTM_PL_TT)) {
+		/* bind is enought */
+		radeon_move_null(bo, new_mem);
+		return 0;
+	}
+	if (!rdev->cp.ready) {
+		/* use memcpy */
+		DRM_ERROR("CP is not ready use memcpy.\n");
+		return ttm_bo_move_memcpy(bo, evict, no_wait, new_mem);
+	}
+
+	if (old_mem->mem_type == TTM_PL_VRAM &&
+	    new_mem->mem_type == TTM_PL_SYSTEM) {
+		return radeon_move_vram_ram(bo, evict, interruptible,
+					    no_wait, new_mem);
+	} else if (old_mem->mem_type == TTM_PL_SYSTEM &&
+		   new_mem->mem_type == TTM_PL_VRAM) {
+		return radeon_move_ram_vram(bo, evict, interruptible,
+					    no_wait, new_mem);
+	} else {
+		r = radeon_move_blit(bo, evict, no_wait, new_mem, old_mem);
+		if (unlikely(r)) {
+			return r;
+		}
+	}
+	return r;
+}
+
+const uint32_t radeon_mem_prios[] = {
+	TTM_PL_VRAM,
+	TTM_PL_TT,
+	TTM_PL_SYSTEM,
+};
+
+const uint32_t radeon_busy_prios[] = {
+	TTM_PL_TT,
+	TTM_PL_VRAM,
+	TTM_PL_SYSTEM,
+};
+
+static int radeon_sync_obj_wait(void *sync_obj, void *sync_arg,
+				bool lazy, bool interruptible)
+{
+	return radeon_fence_wait((struct radeon_fence *)sync_obj, interruptible);
+}
+
+static int radeon_sync_obj_flush(void *sync_obj, void *sync_arg)
+{
+	return 0;
+}
+
+static void radeon_sync_obj_unref(void **sync_obj)
+{
+	radeon_fence_unref((struct radeon_fence **)sync_obj);
+}
+
+static void *radeon_sync_obj_ref(void *sync_obj)
+{
+	return radeon_fence_ref((struct radeon_fence *)sync_obj);
+}
+
+static bool radeon_sync_obj_signaled(void *sync_obj, void *sync_arg)
+{
+	return radeon_fence_signaled((struct radeon_fence *)sync_obj);
+}
+
+static struct ttm_bo_driver radeon_bo_driver = {
+	.mem_type_prio = radeon_mem_prios,
+	.mem_busy_prio = radeon_busy_prios,
+	.num_mem_type_prio = ARRAY_SIZE(radeon_mem_prios),
+	.num_mem_busy_prio = ARRAY_SIZE(radeon_busy_prios),
+	.create_ttm_backend_entry = &radeon_create_ttm_backend_entry,
+	.invalidate_caches = &radeon_invalidate_caches,
+	.init_mem_type = &radeon_init_mem_type,
+	.evict_flags = &radeon_evict_flags,
+	.move = &radeon_bo_move,
+	.verify_access = &radeon_verify_access,
+	.sync_obj_signaled = &radeon_sync_obj_signaled,
+	.sync_obj_wait = &radeon_sync_obj_wait,
+	.sync_obj_flush = &radeon_sync_obj_flush,
+	.sync_obj_unref = &radeon_sync_obj_unref,
+	.sync_obj_ref = &radeon_sync_obj_ref,
+};
+
+int radeon_ttm_init(struct radeon_device *rdev)
+{
+	int r;
+
+	r = radeon_ttm_global_init(rdev);
+	if (r) {
+		return r;
+	}
+	/* No others user of address space so set it to 0 */
+	r = ttm_bo_device_init(&rdev->mman.bdev,
+			       rdev->mman.mem_global_ref.object,
+			       &radeon_bo_driver, DRM_FILE_PAGE_OFFSET);
+	if (r) {
+		DRM_ERROR("failed initializing buffer object driver(%d).\n", r);
+		return r;
+	}
+	r = ttm_bo_init_mm(&rdev->mman.bdev, TTM_PL_VRAM, 0,
+			   ((rdev->mc.aper_size) >> PAGE_SHIFT));
+	if (r) {
+		DRM_ERROR("Failed initializing VRAM heap.\n");
+		return r;
+	}
+	r = radeon_object_create(rdev, NULL, 256 * 1024, true,
+				 RADEON_GEM_DOMAIN_VRAM, false,
+				 &rdev->stollen_vga_memory);
+	if (r) {
+		return r;
+	}
+	r = radeon_object_pin(rdev->stollen_vga_memory, RADEON_GEM_DOMAIN_VRAM, NULL);
+	if (r) {
+		radeon_object_unref(&rdev->stollen_vga_memory);
+		return r;
+	}
+	DRM_INFO("radeon: %uM of VRAM memory ready\n",
+		 rdev->mc.vram_size / (1024 * 1024));
+	r = ttm_bo_init_mm(&rdev->mman.bdev, TTM_PL_TT, 0,
+			   ((rdev->mc.gtt_size) >> PAGE_SHIFT));
+	if (r) {
+		DRM_ERROR("Failed initializing GTT heap.\n");
+		return r;
+	}
+	DRM_INFO("radeon: %uM of GTT memory ready.\n",
+		 rdev->mc.gtt_size / (1024 * 1024));
+	if (unlikely(rdev->mman.bdev.dev_mapping == NULL)) {
+		rdev->mman.bdev.dev_mapping = rdev->ddev->dev_mapping;
+	}
+	return 0;
+}
+
+void radeon_ttm_fini(struct radeon_device *rdev)
+{
+	if (rdev->stollen_vga_memory) {
+		radeon_object_unpin(rdev->stollen_vga_memory);
+		radeon_object_unref(&rdev->stollen_vga_memory);
+	}
+	ttm_bo_clean_mm(&rdev->mman.bdev, TTM_PL_VRAM);
+	ttm_bo_clean_mm(&rdev->mman.bdev, TTM_PL_TT);
+	ttm_bo_device_release(&rdev->mman.bdev);
+	radeon_gart_fini(rdev);
+	radeon_ttm_global_fini(rdev);
+	DRM_INFO("radeon: ttm finalized\n");
+}
+
+static struct vm_operations_struct radeon_ttm_vm_ops;
+static struct vm_operations_struct *ttm_vm_ops = NULL;
+
+static int radeon_ttm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	struct ttm_buffer_object *bo;
+	int r;
+
+	bo = (struct ttm_buffer_object *)vma->vm_private_data;
+	if (bo == NULL) {
+		return VM_FAULT_NOPAGE;
+	}
+	r = ttm_vm_ops->fault(vma, vmf);
+	return r;
+}
+
+int radeon_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	struct drm_file *file_priv;
+	struct radeon_device *rdev;
+	int r;
+
+	if (unlikely(vma->vm_pgoff < DRM_FILE_PAGE_OFFSET)) {
+		return drm_mmap(filp, vma);
+	}
+
+	file_priv = (struct drm_file *)filp->private_data;
+	rdev = file_priv->minor->dev->dev_private;
+	if (rdev == NULL) {
+		return -EINVAL;
+	}
+	r = ttm_bo_mmap(filp, vma, &rdev->mman.bdev);
+	if (unlikely(r != 0)) {
+		return r;
+	}
+	if (unlikely(ttm_vm_ops == NULL)) {
+		ttm_vm_ops = vma->vm_ops;
+		radeon_ttm_vm_ops = *ttm_vm_ops;
+		radeon_ttm_vm_ops.fault = &radeon_ttm_fault;
+	}
+	vma->vm_ops = &radeon_ttm_vm_ops;
+	return 0;
+}
+
+
+/*
+ * TTM backend functions.
+ */
+struct radeon_ttm_backend {
+	struct ttm_backend		backend;
+	struct radeon_device		*rdev;
+	unsigned long			num_pages;
+	struct page			**pages;
+	struct page			*dummy_read_page;
+	bool				populated;
+	bool				bound;
+	unsigned			offset;
+};
+
+static int radeon_ttm_backend_populate(struct ttm_backend *backend,
+				       unsigned long num_pages,
+				       struct page **pages,
+				       struct page *dummy_read_page)
+{
+	struct radeon_ttm_backend *gtt;
+
+	gtt = container_of(backend, struct radeon_ttm_backend, backend);
+	gtt->pages = pages;
+	gtt->num_pages = num_pages;
+	gtt->dummy_read_page = dummy_read_page;
+	gtt->populated = true;
+	return 0;
+}
+
+static void radeon_ttm_backend_clear(struct ttm_backend *backend)
+{
+	struct radeon_ttm_backend *gtt;
+
+	gtt = container_of(backend, struct radeon_ttm_backend, backend);
+	gtt->pages = NULL;
+	gtt->num_pages = 0;
+	gtt->dummy_read_page = NULL;
+	gtt->populated = false;
+	gtt->bound = false;
+}
+
+
+static int radeon_ttm_backend_bind(struct ttm_backend *backend,
+				   struct ttm_mem_reg *bo_mem)
+{
+	struct radeon_ttm_backend *gtt;
+	int r;
+
+	gtt = container_of(backend, struct radeon_ttm_backend, backend);
+	gtt->offset = bo_mem->mm_node->start << PAGE_SHIFT;
+	if (!gtt->num_pages) {
+		WARN(1, "nothing to bind %lu pages for mreg %p back %p!\n", gtt->num_pages, bo_mem, backend);
+	}
+	r = radeon_gart_bind(gtt->rdev, gtt->offset,
+			     gtt->num_pages, gtt->pages);
+	if (r) {
+		DRM_ERROR("failed to bind %lu pages at 0x%08X\n",
+			  gtt->num_pages, gtt->offset);
+		return r;
+	}
+	gtt->bound = true;
+	return 0;
+}
+
+static int radeon_ttm_backend_unbind(struct ttm_backend *backend)
+{
+	struct radeon_ttm_backend *gtt;
+
+	gtt = container_of(backend, struct radeon_ttm_backend, backend);
+	radeon_gart_unbind(gtt->rdev, gtt->offset, gtt->num_pages);
+	gtt->bound = false;
+	return 0;
+}
+
+static void radeon_ttm_backend_destroy(struct ttm_backend *backend)
+{
+	struct radeon_ttm_backend *gtt;
+
+	gtt = container_of(backend, struct radeon_ttm_backend, backend);
+	if (gtt->bound) {
+		radeon_ttm_backend_unbind(backend);
+	}
+	kfree(gtt);
+}
+
+static struct ttm_backend_func radeon_backend_func = {
+	.populate = &radeon_ttm_backend_populate,
+	.clear = &radeon_ttm_backend_clear,
+	.bind = &radeon_ttm_backend_bind,
+	.unbind = &radeon_ttm_backend_unbind,
+	.destroy = &radeon_ttm_backend_destroy,
+};
+
+struct ttm_backend *radeon_ttm_backend_create(struct radeon_device *rdev)
+{
+	struct radeon_ttm_backend *gtt;
+
+	gtt = kzalloc(sizeof(struct radeon_ttm_backend), GFP_KERNEL);
+	if (gtt == NULL) {
+		return NULL;
+	}
+	gtt->backend.bdev = &rdev->mman.bdev;
+	gtt->backend.flags = 0;
+	gtt->backend.func = &radeon_backend_func;
+	gtt->rdev = rdev;
+	gtt->pages = NULL;
+	gtt->num_pages = 0;
+	gtt->dummy_read_page = NULL;
+	gtt->populated = false;
+	gtt->bound = false;
+	return &gtt->backend;
+}