[PATCH 3/5] iommu/rockchip: add sanity check for virtual device

[Shunqian Zheng]

From: Simon <xxm at rock-chips.com>

We mark DRM as "virtual" device by checking it's group,
which may no longer true with the new rockchip drm drv in
https://patchwork.kernel.org/patch/8876331/.

Checking the group->iommu_data for virtual device.

Signed-off-by: Simon <xxm at rock-chips.com>
---
 drivers/iommu/rockchip-iommu.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index 3c16ec3..043d18c 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -764,6 +764,7 @@ static size_t rk_iommu_unmap(struct iommu_domain *domain, unsigned long _iova,
 	return unmap_size;
 }
 
+/* Return NULL for a virtual device like DRM */
 static struct rk_iommu *rk_iommu_from_dev(struct device *dev)
 {
 	struct iommu_group *group;
@@ -774,6 +775,11 @@ static struct rk_iommu *rk_iommu_from_dev(struct device *dev)
 	if (!group)
 		return NULL;
 	iommu_dev = iommu_group_get_iommudata(group);
+	if (!iommu_dev) {
+		dev_info(dev, "Possibly a virtual device\n");
+		return NULL;
+	}
+
 	rk_iommu = dev_get_drvdata(iommu_dev);
 	iommu_group_put(group);
 
@@ -791,7 +797,6 @@ static int rk_iommu_attach_device(struct iommu_domain *domain,
 
 	/*
 	 * Allow 'virtual devices' (e.g., drm) to attach to domain.
-	 * Such a device does not belong to an iommu group.
 	 */
 	iommu = rk_iommu_from_dev(dev);
 	if (!iommu)
-- 
1.9.1