diff --git a/src/ast_drv.c b/src/ast_drv.c
index 01c3751f9df0882e788853fa8c95b8781627438f..ea6e913ebbb840244a76624146c0c7d55a711592 100644
--- a/src/ast_drv.c
+++ b/src/ast_drv.c
@@ -226,11 +226,30 @@ static struct pci_driver ast_pci_driver = {
 
 DEFINE_DRM_GEM_FOPS(ast_fops);
 
+#define DRM_AST_VRAM_TYPE_DEVICE 0x0
+#define DRM_IOCTL_AST_VRAM_TYPE_DEVICE	DRM_IO(DRM_COMMAND_BASE\
+	+ DRM_AST_VRAM_TYPE_DEVICE)
+
+static int ast_ioctl_check_5c01_device(struct drm_device *dev, void *data,
+				struct drm_file *file_priv)
+{
+	struct ast_private *priv = to_ast_private(dev);
+
+	return priv->is_5c01_device ? 1 : 0;
+}
+
+static const struct drm_ioctl_desc ast_ioctls[] = {
+	/* for test, none so far */
+	DRM_IOCTL_DEF_DRV(AST_VRAM_TYPE_DEVICE, ast_ioctl_check_5c01_device,
+						DRM_AUTH|DRM_UNLOCKED),
+};
+
 static struct drm_driver driver = {
 	.driver_features = DRIVER_ATOMIC |
 			   DRIVER_GEM |
 			   DRIVER_MODESET,
-
+	.ioctls = ast_ioctls,
+	.num_ioctls = ARRAY_SIZE(ast_ioctls),
 	.fops = &ast_fops,
 	.name = DRIVER_NAME,
 	.desc = DRIVER_DESC,
diff --git a/src/ast_drv.h b/src/ast_drv.h
index 4d7c12e64d3bc6cf764e7d1c3a3457d93d534c91..666515f3d580fcb15b16d7c0dfa22cabed296e6c 100644
--- a/src/ast_drv.h
+++ b/src/ast_drv.h
@@ -128,6 +128,7 @@ struct ast_private {
 	struct drm_plane primary_plane;
 	struct drm_plane cursor_plane;
 
+	bool is_5c01_device;
 	bool support_wide_screen;
 	bool support_newvga_mode;
 	bool RefCLK25MHz;	
diff --git a/src/ast_mm.c b/src/ast_mm.c
index 9186ec3ebbe0934ee96dc75308f28d23a53802a6..ce12dcb5c8a43bada22c347b234e1805bf36d945 100644
--- a/src/ast_mm.c
+++ b/src/ast_mm.c
@@ -74,6 +74,52 @@ static u32 ast_get_vram_size(struct ast_private *ast)
 	return vram_size;
 }
 
+static int ast_driver_io_mem_reserve(struct ttm_bo_device *bdev,
+									struct ttm_resource *mem)
+{
+	struct drm_vram_mm *vmm = drm_vram_mm_of_bdev(bdev);
+	size_t bus_size = (size_t)mem->num_pages << PAGE_SHIFT;
+
+	switch (mem->mem_type) {
+	case TTM_PL_SYSTEM:     /* nothing to do */
+			break;
+	case TTM_PL_VRAM:
+			mem->bus.offset = (mem->start << PAGE_SHIFT) + vmm->vram_base;
+			mem->bus.is_iomem = true;
+
+			mem->placement = TTM_PL_FLAG_UNCACHED;
+			mem->bus.addr = ioremap(mem->bus.offset, bus_size);
+
+			if (!mem->bus.addr)
+				return -ENOMEM;
+
+			break;
+	default:
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
+static bool ast_pci_host_is_5c01(struct pci_bus *bus)
+{
+	struct pci_bus *child = bus;
+	struct pci_dev *root = NULL;
+
+	while (child) {
+		if (child->parent->parent)
+			child = child->parent;
+		else
+			break;
+	}
+
+	root = child->self;
+
+	if ((root->vendor == 0x1db7) && (root->device == 0x5c01))
+		return true;
+	return false;
+}
+
 static void ast_mm_release(struct drm_device *dev, void *ptr)
 {
 	struct ast_private *ast = to_ast_private(dev);
@@ -88,6 +134,7 @@ int ast_mm_init(struct ast_private *ast)
 	u32 vram_size;
 	int ret;
 	struct drm_device *dev = ast->dev;
+	struct pci_dev *pdev = to_pci_dev(dev->dev);
 
 	vram_size = ast_get_vram_size(ast);
 
@@ -98,6 +145,13 @@ int ast_mm_init(struct ast_private *ast)
 		return ret;
 	}
 
+	if (ast_pci_host_is_5c01(pdev->bus) && dev->vram_mm->bdev.driver) {
+		ast->is_5c01_device = true;
+		dev->vram_mm->bdev.driver->io_mem_reserve = ast_driver_io_mem_reserve;
+	} else {
+		ast->is_5c01_device = false;
+	}
+
 	arch_io_reserve_memtype_wc(pci_resource_start(dev->pdev, 0),
 				   pci_resource_len(dev->pdev, 0));
 	ast->fb_mtrr = arch_phys_wc_add(pci_resource_start(dev->pdev, 0),