On 30/08/2019 19:16, Krishna Reddy wrote:

 From the previous discussions, I got the impression that other than the 
'novel' way they're integrated, the actual SMMU implementations were unmodified 
Arm MMU-500s. Is that the case, or have I misread something?

The ARM MMU-500 implementation is unmodified.  It is the way the are integrated 
and used together(for interleaved accesses) is different from regular ARM 
I have added it to get the model number and to be able differentiate the SMMU 
implementation in arm-smmu-impl.c.

In that case, I would rather keep smmu->model representing the MMU-500 microarchitecture - since you'll still want to pick up errata workarounds etc. for that - and detect the Tegra integration via an explicit of_device_is_compatible() check in arm_smmu_impl_init(). For comparison, under ACPI we'd probably have to detect integration details by looking at table headers, separately from the IORT "Model" field, so I'd prefer if the DT vs. ACPI handling didn't diverge more than necessary.

Of course, that immediately opens the question of how best to combine arm_mmu500_impl with nsmmu_impl, but hey, one step at a time :)

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