On Fri, Aug 09, 2019 at 06:07:52PM +0100, Robin Murphy wrote:
> Allocating and initialising a context for a domain is another point
> where certain implementations are known to want special behaviour.
> Currently the other half of the Cavium workaround comes into play here,
> so let's finish the job to get the whole thing right out of the way.
> 
> Signed-off-by: Robin Murphy <robin.mur...@arm.com>
> ---
>  drivers/iommu/arm-smmu-impl.c | 39 +++++++++++++++++++++++++--
>  drivers/iommu/arm-smmu.c      | 51 +++++++----------------------------
>  drivers/iommu/arm-smmu.h      | 42 +++++++++++++++++++++++++++--
>  3 files changed, 86 insertions(+), 46 deletions(-)
> 
> diff --git a/drivers/iommu/arm-smmu-impl.c b/drivers/iommu/arm-smmu-impl.c
> index c8904da08354..7a657d47b6ec 100644
> --- a/drivers/iommu/arm-smmu-impl.c
> +++ b/drivers/iommu/arm-smmu-impl.c
> @@ -48,6 +48,12 @@ const struct arm_smmu_impl calxeda_impl = {
>  };
>  
>  
> +struct cavium_smmu {
> +     struct arm_smmu_device smmu;
> +     u32 id_base;
> +};
> +#define to_csmmu(s)  container_of(s, struct cavium_smmu, smmu)

To be honest with you, I'd just use container_of directly for the two
callsites that need it. "to_csmmu" isn't a great name when we're also got
the calxeda thing in here.

>  static int cavium_cfg_probe(struct arm_smmu_device *smmu)
>  {
>       static atomic_t context_count = ATOMIC_INIT(0);
> @@ -56,17 +62,46 @@ static int cavium_cfg_probe(struct arm_smmu_device *smmu)
>        * Ensure ASID and VMID allocation is unique across all SMMUs in
>        * the system.
>        */
> -     smmu->cavium_id_base = atomic_fetch_add(smmu->num_context_banks,
> +     to_csmmu(smmu)->id_base = atomic_fetch_add(smmu->num_context_banks,
>                                                  &context_count);
>       dev_notice(smmu->dev, "\tenabling workaround for Cavium erratum 
> 27704\n");
>  
>       return 0;
>  }
>  
> +int cavium_init_context(struct arm_smmu_domain *smmu_domain)
> +{
> +     u32 id_base = to_csmmu(smmu_domain->smmu)->id_base;
> +
> +     if (smmu_domain->stage == ARM_SMMU_DOMAIN_S2)
> +             smmu_domain->cfg.vmid += id_base;
> +     else
> +             smmu_domain->cfg.asid += id_base;
> +
> +     return 0;
> +}
> +
>  const struct arm_smmu_impl cavium_impl = {
>       .cfg_probe = cavium_cfg_probe,
> +     .init_context = cavium_init_context,
>  };
>  
> +struct arm_smmu_device *cavium_smmu_impl_init(struct arm_smmu_device *smmu)
> +{
> +     struct cavium_smmu *csmmu;
> +
> +     csmmu = devm_kzalloc(smmu->dev, sizeof(*csmmu), GFP_KERNEL);
> +     if (!csmmu)
> +             return ERR_PTR(-ENOMEM);
> +
> +     csmmu->smmu = *smmu;
> +     csmmu->smmu.impl = &cavium_impl;
> +
> +     devm_kfree(smmu->dev, smmu);
> +
> +     return &csmmu->smmu;
> +}
> +
>  
>  #define ARM_MMU500_ACTLR_CPRE                (1 << 1)
>  
> @@ -121,7 +156,7 @@ struct arm_smmu_device *arm_smmu_impl_init(struct 
> arm_smmu_device *smmu)
>               smmu->impl = &calxeda_impl;
>  
>       if (smmu->model == CAVIUM_SMMUV2)
> -             smmu->impl = &cavium_impl;
> +             return cavium_smmu_impl_init(smmu);
>  
>       if (smmu->model == ARM_MMU500)
>               smmu->impl = &arm_mmu500_impl;

Maybe rework this so we do the calxeda detection first (and return if we
match), followed by a switch on smmu->model to make it crystal clear that
we match only one?

Will
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