On Fri, Aug 28, 2020 at 05:28:22PM +0800, Zenghui Yu wrote:

On 2020/5/20 1:54, Jean-Philippe Brucker wrote:

quoted

@@ -4454,6 +4470,12 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
  			smmu->features |= ARM_SMMU_FEAT_E2H;
  	}
+	if (reg & (IDR0_HA | IDR0_HD)) {
+		smmu->features |= ARM_SMMU_FEAT_HA;
+		if (reg & IDR0_HD)
+			smmu->features |= ARM_SMMU_FEAT_HD;
+	}
+

nitpick:

As per the IORT spec (DEN0049D, 3.1.1.2 SMMUv3 node, Table 10), the
"HTTU Override" flag of the SMMUv3 node can override the value in
SMMU_IDR0.HTTU. You may want to check this bit before selecting the
{HA,HD} features and shout if there is a mismatch between firmware and
the SMMU implementation. Just like how ARM_SMMU_FEAT_COHERENCY is
selected.

Thanks for pointing this out, I didn't know about these flags but have
added them to the patch now.

Thanks,
Jean