[PATCH v2] iommu/rockchip: prevent iommus dead loop when two masters share one IOMMU

[Simon Xue <xxm@rock-chips.com>]

When two masters share an IOMMU, calling ops->of_xlate during
the second master's driver init may overwrite iommu->domain set
by the first. This causes the check if (iommu->domain == domain)
in rk_iommu_attach_device() to fail, resulting in the same
iommu->node being added twice to &rk_domain->iommus, which can
lead to an infinite loop in subsequent &rk_domain->iommus operations.

Fixes: 25c2325575cc ("iommu/rockchip: Add missing set_platform_dma_ops callback")

Signed-off-by: Simon Xue <xxm@rock-chips.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>

v2:
   No functional changes.
---
 drivers/iommu/rockchip-iommu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index 22f74ba33a0e..e6bb3c784017 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -1157,7 +1157,6 @@ static int rk_iommu_of_xlate(struct device *dev,
 		return -ENOMEM;
 
 	data->iommu = platform_get_drvdata(iommu_dev);
-	data->iommu->domain = &rk_identity_domain;
 	dev_iommu_priv_set(dev, data);
 
 	platform_device_put(iommu_dev);
@@ -1195,6 +1194,8 @@ static int rk_iommu_probe(struct platform_device *pdev)
 	if (!iommu)
 		return -ENOMEM;
 
+	iommu->domain = &rk_identity_domain;
+
 	platform_set_drvdata(pdev, iommu);
 	iommu->dev = dev;
 	iommu->num_mmu = 0;
-- 
2.34.1