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From:   Rob Clark <robdclark@gmail.com>
To:     iommu@lists.linux-foundation.org
Cc:     freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org,
        Robin Murphy <robin.murphy@arm.com>,
        Johan Hovold <johan@kernel.org>,
        Rob Clark <robdclark@chromium.org>, stable@vger.kernel.org,
        Will Deacon <will@kernel.org>, Joerg Roedel <joro@8bytes.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Bjorn Andersson <quic_bjorande@quicinc.com>,
        Manivannan Sadhasivam <mani@kernel.org>,
        Danila Tikhonov <danila@jiaxyga.com>,
        Elliot Berman <quic_eberman@quicinc.com>,
        linux-arm-kernel@lists.infradead.org (moderated list:ARM SMMU DRIVERS),
        iommu@lists.linux.dev (open list:IOMMU SUBSYSTEM),
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Subject: [PATCH v2] iommu/arm-smmu-qcom: Add missing GMU entry to match table
Date:   Sun, 10 Dec 2023 10:06:53 -0800
Message-ID: <20231210180655.75542-1-robdclark@gmail.com>
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From: Rob Clark <robdclark@chromium.org>

In some cases the firmware expects cbndx 1 to be assigned to the GMU,
so we also want the default domain for the GMU to be an identy domain.
This way it does not get a context bank assigned.  Without this, both
of_dma_configure() and drm/msm's iommu_domain_attach() will trigger
allocating and configuring a context bank.  So GMU ends up attached to
both cbndx 1 and later cbndx 2.  This arrangement seemingly confounds
and surprises the firmware if the GPU later triggers a translation
fault, resulting (on sc8280xp / lenovo x13s, at least) in the SMMU
getting wedged and the GPU stuck without memory access.

Cc: stable@vger.kernel.org
Signed-off-by: Rob Clark <robdclark@chromium.org>
---

I didn't add a fixes tag because really this issue has been there
all along, but either didn't matter with other firmware or we didn't 
notice the problem.

 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index 549ae4dba3a6..d326fa230b96 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -243,6 +243,7 @@ static int qcom_adreno_smmu_init_context(struct arm_smmu_domain *smmu_domain,
 
 static const struct of_device_id qcom_smmu_client_of_match[] __maybe_unused = {
 	{ .compatible = "qcom,adreno" },
+	{ .compatible = "qcom,adreno-gmu" },
 	{ .compatible = "qcom,mdp4" },
 	{ .compatible = "qcom,mdss" },
 	{ .compatible = "qcom,sc7180-mdss" },
-- 
2.43.0