Re: [PATCHv2 3/6] iommu/arm-smmu: Implement iommu_ops->def_domain_type call-back

Robin Murphy
2020-04-20T15:26:31Z

On 2020-04-20 3:37 pm, Sai Prakash Ranjan wrote:
> Implement the new def_domain_type call-back for the ARM
> SMMU driver. We need this to support requesting the domain
> type by the client devices.
>
> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> ---
> drivers/iommu/arm-smmu.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index e622f4e33379..b5d1d52dfbb8 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -1609,6 +1609,25 @@ static void arm_smmu_get_resv_regions(struct device *dev,
> iommu_dma_get_resv_regions(dev, head);
> }
>
> +static int arm_smmu_def_domain_type(struct device *dev)
> +{
> + struct iommu_fwspec *fwspec;
> + struct arm_smmu_device *smmu;
> +
> + fwspec = dev_iommu_fwspec_get(dev);
> + if (!fwspec || fwspec->ops != &arm_smmu_ops)
> + return -ENODEV;
> +
> + smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode);
> + if (!smmu)
> + return -ENODEV;
> +

AFAICS this should only ever be called for a device in a group, which
means an initial ->probe_device has succeeded and rather than
defensively going the long way round, we can safely assume this:

struct arm_smmu_master_cfg = dev_iommu_priv_get(dev);
struct arm_smmu_impl *impl = cfg->smmu->impl;

if (impl && impl->req_domain)
return impl->req_domain(dev);

Or have I misunderstood the flow?

Robin.

> + if (smmu->impl && smmu->impl->req_domain)
> + return smmu->impl->req_domain(dev);
> +
> + return 0;
> +}
> +
> static struct iommu_ops arm_smmu_ops = {
> .capable = arm_smmu_capable,
> .domain_alloc = arm_smmu_domain_alloc,
> @@ -1627,6 +1646,7 @@ static struct iommu_ops arm_smmu_ops = {
> .of_xlate = arm_smmu_of_xlate,
> .get_resv_regions = arm_smmu_get_resv_regions,
> .put_resv_regions = generic_iommu_put_resv_regions,
> + .def_domain_type = arm_smmu_def_domain_type,
> .pgsize_bitmap = -1UL, /* Restricted during device attach */
> };
>
>