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

From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
	linux-arm-msm@vger.kernel.org, Joerg Roedel <joro@8bytes.org>,
	Jordan Crouse <jcrouse@codeaurora.org>,
	Evan Green <evgreen@chromium.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Rob Clark <robdclark@gmail.com>,
	iommu@lists.linux-foundation.org,
	Sibi Sankar <sibis@codeaurora.org>,
	Stephen Boyd <swboyd@chromium.org>, Will Deacon <will@kernel.org>,
	Matthias Kaehlcke <mka@chromium.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCHv2 2/6] iommu/arm-smmu: Allow client devices to select direct mapping
Date: Mon, 20 Apr 2020 21:58:26 +0530	[thread overview]
Message-ID: <65f21f15b90f73e16c0bb5bb75e835e6@codeaurora.org> (raw)
In-Reply-To: <e35b10dc-8e58-f201-8485-9543dafbadfe@arm.com>

On 2020-04-20 21:27, Robin Murphy wrote:
> On 2020-04-20 3:37 pm, 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 | 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

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