drm/nouveau/imem: use fast-path for suspend backup

Before: "imem: suspend completed in 5540487us"
 After: "imem: suspend completed in 1871526us"

Suspend from Fedora 26 gnome desktop on GP102.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nvkm/subdev/bar/base.c

@@ -74,7 +74,6 @@ nvkm_bar_fini(struct nvkm_subdev *subdev, bool suspend)
 {
 	struct nvkm_bar *bar = nvkm_bar(subdev);
 	bar->func->bar1.fini(bar);
-	nvkm_bar_bar2_fini(subdev->device);
 	return 0;
 }
 
@@ -101,6 +100,7 @@ static void *
 nvkm_bar_dtor(struct nvkm_subdev *subdev)
 {
 	struct nvkm_bar *bar = nvkm_bar(subdev);
+	nvkm_bar_bar2_fini(subdev->device);
 	return bar->func->dtor(bar);
 }
 

drivers/gpu/drm/nouveau/nvkm/subdev/instmem/base.c

@@ -46,15 +46,20 @@ nvkm_instobj_save(struct nvkm_instobj *iobj)
 {
 	struct nvkm_memory *memory = &iobj->memory;
 	const u64 size = nvkm_memory_size(memory);
+	void __iomem *map;
 	int i;
 
 	iobj->suspend = kvmalloc(size, GFP_KERNEL);
 	if (!iobj->suspend)
 		return -ENOMEM;
 
+	if (!(map = nvkm_kmap(memory))) {
 		for (i = 0; i < size; i += 4)
 			iobj->suspend[i / 4] = nvkm_ro32(memory, i);
-
+	} else {
+		memcpy_fromio(iobj->suspend, map, size);
+	}
+	nvkm_done(memory);
 	return 0;
 }
 
@@ -157,6 +162,8 @@ nvkm_instmem_fini(struct nvkm_subdev *subdev, bool suspend)
 				return ret;
 		}
 
+		nvkm_bar_bar2_fini(subdev->device);
+
 		list_for_each_entry(iobj, &imem->boot, head) {
 			int ret = nvkm_instobj_save(iobj);
 			if (ret)