drm/tegra: vic: Use common IOMMU attach/detach code

Reuse common code to attach to or detach from an IOMMU domain.

Signed-off-by: Thierry Reding <[e-mail]>

drivers/gpu/drm/tegra/vic.c

···
 	void __iomem *regs;
 	struct tegra_drm_client client;
 	struct host1x_channel *channel;
-	struct iommu_domain *domain;
+	struct iommu_group *group;
 	struct device *dev;
 	struct clk *clk;
 	struct reset_control *rst;
···
 static int vic_init(struct host1x_client *client)
 {
 	struct tegra_drm_client *drm = host1x_to_drm_client(client);
-	struct iommu_group *group = iommu_group_get(client->dev);
 	struct drm_device *dev = dev_get_drvdata(client->parent);
 	struct tegra_drm *tegra = dev->dev_private;
 	struct vic *vic = to_vic(drm);
 	int err;
 
-	if (group && tegra->domain) {
-		err = iommu_attach_group(tegra->domain, group);
-		if (err < 0) {
-			dev_err(vic->dev, "failed to attach to domain: %d\n",
-				err);
-			return err;
-		}
-
-		vic->domain = tegra->domain;
+	vic->group = host1x_client_iommu_attach(client, false);
+	if (IS_ERR(vic->group)) {
+		err = PTR_ERR(vic->group);
+		dev_err(vic->dev, "failed to attach to domain: %d\n", err);
+		return err;
 	}
 
 	vic->channel = host1x_channel_request(client);
···
 free_channel:
 	host1x_channel_put(vic->channel);
 detach:
-	if (group && tegra->domain)
-		iommu_detach_group(tegra->domain, group);
+	host1x_client_iommu_detach(client, vic->group);
 
 	return err;
 }
···
 static int vic_exit(struct host1x_client *client)
 {
 	struct tegra_drm_client *drm = host1x_to_drm_client(client);
-	struct iommu_group *group = iommu_group_get(client->dev);
 	struct drm_device *dev = dev_get_drvdata(client->parent);
 	struct tegra_drm *tegra = dev->dev_private;
 	struct vic *vic = to_vic(drm);
···
 
 	host1x_syncpt_free(client->syncpts[0]);
 	host1x_channel_put(vic->channel);
-
-	if (vic->domain) {
-		iommu_detach_group(vic->domain, group);
-		vic->domain = NULL;
-	}
+	host1x_client_iommu_detach(client, vic->group);
 
 	return 0;
 }