linux-kernel - Re: [PATCH 1/2] iommu: arm-smmu-impl: Convert to a generic reset implementation

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Date:   Thu, 16 Apr 2020 14:33:38 +0100
From:   Robin Murphy <robin.murphy@....com>
To:     Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>,
        Will Deacon <will@...nel.org>, Joerg Roedel <joro@...tes.org>,
        Jordan Crouse <jcrouse@...eaurora.org>,
        Rob Clark <robdclark@...il.com>
Cc:     "iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-msm@...r.kernel.org" <linux-arm-msm@...r.kernel.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Matthias Kaehlcke <mka@...omium.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Tomasz Figa <tfiga@...omium.org>
Subject: Re: [PATCH 1/2] iommu: arm-smmu-impl: Convert to a generic reset
 implementation

On 2020-01-22 11:48 am, Sai Prakash Ranjan wrote:
> Currently the QCOM specific smmu reset implementation is very
> specific to SDM845 SoC and has a wait-for-safe logic which
> may not be required for other SoCs. So move the SDM845 specific
> logic to its specific reset function. Also add SC7180 SMMU
> compatible for calling into QCOM specific implementation.
> 
> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
> ---
>   drivers/iommu/arm-smmu-impl.c |  8 +++++---
>   drivers/iommu/arm-smmu-qcom.c | 16 +++++++++++++---
>   2 files changed, 18 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iommu/arm-smmu-impl.c b/drivers/iommu/arm-smmu-impl.c
> index 74d97a886e93..c75b9d957b70 100644
> --- a/drivers/iommu/arm-smmu-impl.c
> +++ b/drivers/iommu/arm-smmu-impl.c
> @@ -150,6 +150,8 @@ static const struct arm_smmu_impl arm_mmu500_impl = {
>   
>   struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu)
>   {
> +	const struct device_node *np = smmu->dev->of_node;
> +
>   	/*
>   	 * We will inevitably have to combine model-specific implementation
>   	 * quirks with platform-specific integration quirks, but everything
> @@ -166,11 +168,11 @@ struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu)
>   		break;
>   	}
>   
> -	if (of_property_read_bool(smmu->dev->of_node,
> -				  "calxeda,smmu-secure-config-access"))
> +	if (of_property_read_bool(np, "calxeda,smmu-secure-config-access"))
>   		smmu->impl = &calxeda_impl;
>   
> -	if (of_device_is_compatible(smmu->dev->of_node, "qcom,sdm845-smmu-500"))
> +	if (of_device_is_compatible(np, "qcom,sdm845-smmu-500") ||
> +	    of_device_is_compatible(np, "qcom,sc7180-smmu-500"))
>   		return qcom_smmu_impl_init(smmu);
>   
>   	return smmu;
> diff --git a/drivers/iommu/arm-smmu-qcom.c b/drivers/iommu/arm-smmu-qcom.c
> index 24c071c1d8b0..64a4ab270ab7 100644
> --- a/drivers/iommu/arm-smmu-qcom.c
> +++ b/drivers/iommu/arm-smmu-qcom.c
> @@ -15,8 +15,6 @@ static int qcom_sdm845_smmu500_reset(struct arm_smmu_device *smmu)
>   {
>   	int ret;
>   
> -	arm_mmu500_reset(smmu);
> -
>   	/*
>   	 * To address performance degradation in non-real time clients,
>   	 * such as USB and UFS, turn off wait-for-safe on sdm845 based boards,
> @@ -30,8 +28,20 @@ static int qcom_sdm845_smmu500_reset(struct arm_smmu_device *smmu)
>   	return ret;
>   }
>   
> +static int qcom_smmu500_reset(struct arm_smmu_device *smmu)
> +{
> +	const struct device_node *np = smmu->dev->of_node;
> +
> +	arm_mmu500_reset(smmu);
> +
> +	if (of_device_is_compatible(np, "qcom,sdm845-smmu-500"))
> +		return qcom_sdm845_smmu500_reset(smmu);
> +
> +	return 0;
> +}
> +
>   static const struct arm_smmu_impl qcom_smmu_impl = {
> -	.reset = qcom_sdm845_smmu500_reset,
> +	.reset = qcom_smmu500_reset,
>   };

It might be logical to have a separate SDM845 impl rather than 
indirecting within the callback itself, but I'm not too concerned either 
way. For the arm-smmu-impl.c changes,

Reviewed-by: Robin Murphy <robin.murphy@....com>

Thanks,
Robin.

>   
>   struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu)
>