--- zzzz-none-000/linux-3.10.107/drivers/gpu/drm/exynos/exynos_drm_iommu.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/gpu/drm/exynos/exynos_drm_iommu.c	2021-02-04 17:41:59.000000000 +0000
@@ -36,21 +36,25 @@
 		priv->da_start = EXYNOS_DEV_ADDR_START;
 	if (!priv->da_space_size)
 		priv->da_space_size = EXYNOS_DEV_ADDR_SIZE;
-	if (!priv->da_space_order)
-		priv->da_space_order = EXYNOS_DEV_ADDR_ORDER;
 
 	mapping = arm_iommu_create_mapping(&platform_bus_type, priv->da_start,
-						priv->da_space_size,
-						priv->da_space_order);
+						priv->da_space_size);
+
 	if (IS_ERR(mapping))
 		return PTR_ERR(mapping);
 
 	dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms),
 					GFP_KERNEL);
+	if (!dev->dma_parms)
+		goto error;
+
 	dma_set_max_seg_size(dev, 0xffffffffu);
 	dev->archdata.mapping = mapping;
 
 	return 0;
+error:
+	arm_iommu_release_mapping(mapping);
+	return -ENOMEM;
 }
 
 /*
@@ -83,16 +87,20 @@
 	struct device *dev = drm_dev->dev;
 	int ret;
 
-	if (!dev->archdata.mapping) {
-		DRM_ERROR("iommu_mapping is null.\n");
-		return -EFAULT;
-	}
+	if (!dev->archdata.mapping)
+		return 0;
 
 	subdrv_dev->dma_parms = devm_kzalloc(subdrv_dev,
 					sizeof(*subdrv_dev->dma_parms),
 					GFP_KERNEL);
+	if (!subdrv_dev->dma_parms)
+		return -ENOMEM;
+
 	dma_set_max_seg_size(subdrv_dev, 0xffffffffu);
 
+	if (subdrv_dev->archdata.mapping)
+		arm_iommu_detach_device(subdrv_dev);
+
 	ret = arm_iommu_attach_device(subdrv_dev, dev->archdata.mapping);
 	if (ret < 0) {
 		DRM_DEBUG_KMS("failed iommu attach.\n");
@@ -107,8 +115,8 @@
 	 * If iommu attach succeeded, the sub driver would have dma_ops
 	 * for iommu and also all sub drivers have same dma_ops.
 	 */
-	if (!dev->archdata.dma_ops)
-		dev->archdata.dma_ops = subdrv_dev->archdata.dma_ops;
+	if (get_dma_ops(dev) == get_dma_ops(NULL))
+		set_dma_ops(dev, get_dma_ops(subdrv_dev));
 
 	return 0;
 }
@@ -131,6 +139,5 @@
 	if (!mapping || !mapping->domain)
 		return;
 
-	iommu_detach_device(mapping->domain, subdrv_dev);
-	drm_release_iommu_mapping(drm_dev);
+	arm_iommu_detach_device(subdrv_dev);
 }