Re: [PATCH v2 1/3] iommu/arm-smmu: introduction of ACTLR for custom prefetcher settings

From: Bibek Kumar Patro
Date: Wed Nov 15 2023 - 08:54:48 EST



@@ -467,6 +505,9 @@ static struct arm_smmu_device *qcom_smmu_create(struct arm_smmu_device *smmu,
      qsmmu->smmu.impl = impl;
      qsmmu->cfg = data->cfg;

+    if (data->actlrcfg && (data->actlrcfg->size))
+        qsmmu->actlrcfg = data->actlrcfg;

Do we really need to replicate multiple parts of the data, or would it be sensible to just replace qsmmu->cfg with qsmmu->data and handle the further dereferences in the places that want them?


Mm, could not understand this properly. :( Could you help explain more please?
As per my understanding aren't data and qsmmu different structures.
qcom_smmu is a superset of arm_smmu housing additonal properties
and qcom_smmu_match_data is kind of a superset of arm_smmu_impl with
additional specific implmentations, so both needs to be in place?
Apologies if I understood your statement incorrectly.

+
      return &qsmmu->smmu;
  }

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h
index 593910567b88..4b6862715070 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.h
@@ -9,6 +9,7 @@
  struct qcom_smmu {
      struct arm_smmu_device smmu;
      const struct qcom_smmu_config *cfg;
+    const struct actlr_config *actlrcfg;
      bool bypass_quirk;
      u8 bypass_cbndx;
      u32 stall_enabled;
@@ -25,6 +26,7 @@ struct qcom_smmu_config {
  };