From 41c3068cc2fd0ce179b910c4500934786e8156ba Mon Sep 17 00:00:00 2001
From: Thierry Reding <treding@nvidia.com>
Date: Tue, 14 Nov 2017 16:11:28 +0100
Subject: [PATCH] gpu: host1x: Use IOMMU groups

Use IOMMU groups to attach the host1x device to its IOMMU domain. This
is not strictly necessary because the domain isn't shared with any other
device, but it makes the code consistent with how IOMMU is handled in
other drivers and provides an easy way to detect when no IOMMU has been
attached via device tree.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/gpu/host1x/dev.c | 22 +++++++++++++++-------
 drivers/gpu/host1x/dev.h |  1 +
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
index 1f916b579e95..03db71173f5d 100644
--- a/drivers/gpu/host1x/dev.c
+++ b/drivers/gpu/host1x/dev.c
@@ -218,19 +218,24 @@ static int host1x_probe(struct platform_device *pdev)
 		return err;
 	}
 
-	if (iommu_present(&platform_bus_type)) {
+	host->group = iommu_group_get(&pdev->dev);
+	if (host->group) {
 		struct iommu_domain_geometry *geometry;
 		unsigned long order;
 
 		host->domain = iommu_domain_alloc(&platform_bus_type);
-		if (!host->domain)
-			return -ENOMEM;
+		if (!host->domain) {
+			err = -ENOMEM;
+			goto put_group;
+		}
 
-		err = iommu_attach_device(host->domain, &pdev->dev);
+		err = iommu_attach_group(host->domain, host->group);
 		if (err) {
 			if (err == -ENODEV) {
 				iommu_domain_free(host->domain);
 				host->domain = NULL;
+				iommu_group_put(host->group);
+				host->group = NULL;
 				goto skip_iommu;
 			}
 
@@ -296,13 +301,15 @@ fail_unprepare_disable:
 fail_free_channels:
 	host1x_channel_list_free(&host->channel_list);
 fail_detach_device:
-	if (host->domain) {
+	if (host->group && host->domain) {
 		put_iova_domain(&host->iova);
-		iommu_detach_device(host->domain, &pdev->dev);
+		iommu_detach_group(host->domain, host->group);
 	}
 fail_free_domain:
 	if (host->domain)
 		iommu_domain_free(host->domain);
+put_group:
+	iommu_group_put(host->group);
 
 	return err;
 }
@@ -319,8 +326,9 @@ static int host1x_remove(struct platform_device *pdev)
 
 	if (host->domain) {
 		put_iova_domain(&host->iova);
-		iommu_detach_device(host->domain, &pdev->dev);
+		iommu_detach_group(host->domain, host->group);
 		iommu_domain_free(host->domain);
+		iommu_group_put(host->group);
 	}
 
 	return 0;
diff --git a/drivers/gpu/host1x/dev.h b/drivers/gpu/host1x/dev.h
index 502769726480..43e9fabb43a1 100644
--- a/drivers/gpu/host1x/dev.h
+++ b/drivers/gpu/host1x/dev.h
@@ -117,6 +117,7 @@ struct host1x {
 	struct clk *clk;
 	struct reset_control *rst;
 
+	struct iommu_group *group;
 	struct iommu_domain *domain;
 	struct iova_domain iova;
 	dma_addr_t iova_end;