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From:   Dmitry Osipenko <digetx@gmail.com>
To:     Thierry Reding <thierry.reding@gmail.com>,
        Joerg Roedel <joro@8bytes.org>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Krishna Reddy <vdumpa@nvidia.com>,
        Nicolin Chen <nicoleotsuka@gmail.com>,
        Will Deacon <will@kernel.org>
Cc:     iommu@lists.linux-foundation.org, linux-tegra@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v1] iommu/tegra-smmu: Make tegra_smmu_probe_device() to handle all IOMMU phandles
Date:   Fri, 12 Mar 2021 18:54:39 +0300
Message-Id: <20210312155439.18477-1-digetx@gmail.com>
MIME-Version: 1.0
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Precedence: bulk

The tegra_smmu_probe_device() handles only the first IOMMU device-tree
phandle, skipping the rest. Devices like 3D module on Tegra30 have
multiple IOMMU phandles, one for each h/w block, and thus, only one
IOMMU phandle is added to fwspec for the 3D module, breaking GPU.
Previously this problem was masked by tegra_smmu_attach_dev() which
didn't use the fwspec, but parsed the DT by itself. The previous commit
to tegra-smmu driver partially reverted changes that caused problems for
T124 and now we have tegra_smmu_attach_dev() that uses the fwspec and
the old-buggy variant of tegra_smmu_probe_device() which skips secondary
IOMMUs.

Make tegra_smmu_probe_device() not to skip the secondary IOMMUs. This
fixes a partially attached IOMMU of the 3D module on Tegra30 and now GPU
works properly once again.

Fixes: 765a9d1d02b2 ("iommu/tegra-smmu: Fix mc errors on tegra124-nyan")
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/iommu/tegra-smmu.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 97eb62f667d2..602aab98c079 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -849,12 +849,11 @@ static struct iommu_device *tegra_smmu_probe_device(struct device *dev)
 		smmu = tegra_smmu_find(args.np);
 		if (smmu) {
 			err = tegra_smmu_configure(smmu, dev, &args);
-			of_node_put(args.np);
 
-			if (err < 0)
+			if (err < 0) {
+				of_node_put(args.np);
 				return ERR_PTR(err);
-
-			break;
+			}
 		}
 
 		of_node_put(args.np);
-- 
2.29.2