iommu/arm-smmu-qcom: Move the adreno smmu specific impl

Adreno(GPU) SMMU and APSS(Application Processor SubSystem) SMMU
both implement "arm,mmu-500" in some QTI SoCs and to run through
adreno smmu specific implementation such as enabling split pagetables
support, we need to match the "qcom,adreno-smmu" compatible first
before apss smmu or else we will be running apps smmu implementation
for adreno smmu and the additional features for adreno smmu is never
set. For ex: we have "qcom,sc7280-smmu-500" compatible for both apps
and adreno smmu implementing "arm,mmu-500", so the adreno smmu
implementation is never reached because the current sequence checks
for apps smmu compatible(qcom,sc7280-smmu-500) first and runs that
specific impl and we never reach adreno smmu specific implementation.

Suggested-by: Akhil P Oommen <akhilpo@codeaurora.org>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Jordan Crouse <jordan@cosmicpenguin.net>
Link: https://lore.kernel.org/r/c42181d313fdd440011541a28cde8cd10fffb9d3.1623155117.git.saiprakash.ranjan@codeaurora.org
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index e93b5db..83c3256 100644 (file)
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -370,11 +370,17 @@ struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu)
                        return qcom_smmu_create(smmu, &qcom_smmu_impl);
        }
 
-       if (of_match_node(qcom_smmu_impl_of_match, np))
-               return qcom_smmu_create(smmu, &qcom_smmu_impl);
-
+       /*
+        * Do not change this order of implementation, i.e., first adreno
+        * smmu impl and then apss smmu since we can have both implementing
+        * arm,mmu-500 in which case we will miss setting adreno smmu specific
+        * features if the order is changed.
+        */
        if (of_device_is_compatible(np, "qcom,adreno-smmu"))
                return qcom_smmu_create(smmu, &qcom_adreno_smmu_impl);
 
+       if (of_match_node(qcom_smmu_impl_of_match, np))
+               return qcom_smmu_create(smmu, &qcom_smmu_impl);
+
        return smmu;
 }