Messages in this thread | | | Subject | Re: [PATCH 2/2] iommu/arm-smmu: Allow client devices to select direct mapping | From | Robin Murphy <> | Date | Thu, 16 Apr 2020 14:58:25 +0100 |
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On 2020-01-22 11:48 am, Sai Prakash Ranjan wrote: > From: Jordan Crouse <jcrouse@codeaurora.org> > > Some client devices want to directly map the IOMMU themselves instead > of using the DMA domain. Allow those devices to opt in to direct > mapping by way of a list of compatible strings. > > Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org> > Co-developed-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> > Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> > --- > drivers/iommu/arm-smmu-qcom.c | 39 +++++++++++++++++++++++++++++++++++ > drivers/iommu/arm-smmu.c | 3 +++ > drivers/iommu/arm-smmu.h | 5 +++++ > 3 files changed, 47 insertions(+) > > diff --git a/drivers/iommu/arm-smmu-qcom.c b/drivers/iommu/arm-smmu-qcom.c > index 64a4ab270ab7..ff746acd1c81 100644 > --- a/drivers/iommu/arm-smmu-qcom.c > +++ b/drivers/iommu/arm-smmu-qcom.c > @@ -3,6 +3,7 @@ > * Copyright (c) 2019, The Linux Foundation. All rights reserved. > */ > > +#include <linux/of_device.h> > #include <linux/qcom_scm.h> > > #include "arm-smmu.h" > @@ -11,6 +12,43 @@ struct qcom_smmu { > struct arm_smmu_device smmu; > }; > > +static const struct arm_smmu_client_match_data qcom_adreno = { > + .direct_mapping = true, > +}; > + > +static const struct arm_smmu_client_match_data qcom_mdss = { > + .direct_mapping = true, > +};
Might it make sense to group these by the desired SMMU behaviour rather than (apparently) what kind of device the client happens to be, which seems like a completely arbitrary distinction from the SMMU driver's PoV?
> + > +static const struct of_device_id qcom_smmu_client_of_match[] = { > + { .compatible = "qcom,adreno", .data = &qcom_adreno }, > + { .compatible = "qcom,mdp4", .data = &qcom_mdss }, > + { .compatible = "qcom,mdss", .data = &qcom_mdss }, > + { .compatible = "qcom,sc7180-mdss", .data = &qcom_mdss }, > + { .compatible = "qcom,sdm845-mdss", .data = &qcom_mdss }, > + {}, > +}; > + > +static const struct arm_smmu_client_match_data * > +qcom_smmu_client_data(struct device *dev) > +{ > + const struct of_device_id *match = > + of_match_device(qcom_smmu_client_of_match, dev); > + > + return match ? match->data : NULL;
of_device_get_match_data() is your friend.
> +} > + > +static int qcom_smmu_request_domain(struct device *dev) > +{ > + const struct arm_smmu_client_match_data *client; > + > + client = qcom_smmu_client_data(dev); > + if (client) > + iommu_request_dm_for_dev(dev); > + > + return 0; > +} > + > static int qcom_sdm845_smmu500_reset(struct arm_smmu_device *smmu) > { > int ret; > @@ -41,6 +79,7 @@ static int qcom_smmu500_reset(struct arm_smmu_device *smmu) > } > > static const struct arm_smmu_impl qcom_smmu_impl = { > + .req_domain = qcom_smmu_request_domain, > .reset = qcom_smmu500_reset, > }; > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index 16c4b87af42b..67dd9326247a 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -1448,6 +1448,9 @@ static int arm_smmu_add_device(struct device *dev) > device_link_add(dev, smmu->dev, > DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_SUPPLIER); > > + if (smmu->impl && smmu->impl->req_domain) > + return smmu->impl->req_domain(dev); > +
There are about 5 different patchsets flying around at the moment that all touch default domain allocation, so this is a fast-moving target, but I think where the dust should settle is with arm_smmu_ops forwarding .def_domain_type (or whatever it ends up as) calls to arm_smmu_impl as appropriate.
> return 0; > > out_cfg_free: > diff --git a/drivers/iommu/arm-smmu.h b/drivers/iommu/arm-smmu.h > index 8d1cd54d82a6..059dc9c39f64 100644 > --- a/drivers/iommu/arm-smmu.h > +++ b/drivers/iommu/arm-smmu.h > @@ -244,6 +244,10 @@ enum arm_smmu_arch_version { > ARM_SMMU_V2, > }; > > +struct arm_smmu_client_match_data { > + bool direct_mapping; > +};
Does this need to be public? I don't see the other users...
Robin.
> + > enum arm_smmu_implementation { > GENERIC_SMMU, > ARM_MMU500, > @@ -386,6 +390,7 @@ struct arm_smmu_impl { > int (*init_context)(struct arm_smmu_domain *smmu_domain); > void (*tlb_sync)(struct arm_smmu_device *smmu, int page, int sync, > int status); > + int (*req_domain)(struct device *dev); > }; > > static inline void __iomem *arm_smmu_page(struct arm_smmu_device *smmu, int n) >
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