On 2021-02-25 23:36, Jordan Crouse wrote:

On Thu, Feb 25, 2021 at 03:54:10PM +0530, Sai Prakash Ranjan wrote:

quoted

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 <redacted>
Signed-off-by: Sai Prakash Ranjan <redacted>
---

Its either this or we add a new compatible for adreno smmu 
implementing
arm,mmu-500 like "qcom,sc7280-adreno-smmu-500".

---
 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c 

b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index bea3ee0dabc2..7d0fc2c8e72f 100644

--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c

@@ -345,11 +345,11 @@ struct arm_smmu_device 

*qcom_smmu_impl_init(struct arm_smmu_device *smmu)
 {
 	const struct device_node *np = smmu->dev->of_node;

-	if (of_match_node(qcom_smmu_impl_of_match, np))
-		return qcom_smmu_create(smmu, &qcom_smmu_impl);
-
 	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);
+

It would be good to add a comment here explaining the order here so we
don't accidentally reorganize ourselves back into a problem later.

Sure its better, will add it.

Thanks,
Sai

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