Re: [PATCHv2 2/6] iommu/arm-smmu: Allow client devices to select direct mapping

[Sai Prakash Ranjan]

On 2020-04-20 21:27, Robin Murphy wrote:
> On 2020-04-20 3:37 pm, Sai Prakash Ranjan wrote:
> > From: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>
> >
> > 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@xxxxxxxxxxxxxx>
> > Co-developed-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
> > Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
> > ---
> >   drivers/iommu/arm-smmu-qcom.c | 19 +++++++++++++++++++
> >   drivers/iommu/arm-smmu.h      |  1 +
> >   2 files changed, 20 insertions(+)
> >
> > diff --git a/drivers/iommu/arm-smmu-qcom.c 
> > b/drivers/iommu/arm-smmu-qcom.c
> > index 64a4ab270ab7..0b3f159065aa 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 +12,23 @@ struct qcom_smmu {
> >   	struct arm_smmu_device smmu;
> >   };
> >   +static const struct of_device_id qcom_smmu_client_of_match[] = {
> > +	{ .compatible = "qcom,adreno" },
> > +	{ .compatible = "qcom,mdp4" },
> > +	{ .compatible = "qcom,mdss" },
> > +	{ .compatible = "qcom,sc7180-mdss" },
> > +	{ .compatible = "qcom,sdm845-mdss" },
> > +	{ }
> > +};
> > +
> > +static int qcom_smmu_request_domain(struct device *dev)
> > +{
> > +	const struct of_device_id *match =
> > +		of_match_device(qcom_smmu_client_of_match, dev);
> > +
> > +	return match ? IOMMU_DOMAIN_IDENTITY : 0;
> > +}
> > +
> >   static int qcom_sdm845_smmu500_reset(struct arm_smmu_device *smmu)
> >   {
> >   	int ret;
> > @@ -41,6 +59,7 @@ 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.h b/drivers/iommu/arm-smmu.h
> > index 8d1cd54d82a6..662fdb4dccd2 100644
> > --- a/drivers/iommu/arm-smmu.h
> > +++ b/drivers/iommu/arm-smmu.h
> > @@ -386,6 +386,7 @@ 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);
>
> Nit: since the point is to implement the full
> iommu_ops::def_domain_type interface, can we call it def_domain_type
> please?

Sure, will send the next version shortly.

Thanks,
Sai

--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a 
member
of Code Aurora Forum, hosted by The Linux Foundation