Re: [RFC PATCH 3/4] drm/msm/iommu: introduce msm_iommu_disp_new() for msm_kms

[Dmitry Baryshkov]

On Fri, May 17, 2024 at 04:37:58PM -0700, Abhinav Kumar wrote:
> Introduce a new API msm_iommu_disp_new() for display use-cases.
> 
> Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> ---
>  drivers/gpu/drm/msm/msm_iommu.c | 28 ++++++++++++++++++++++++++++
>  drivers/gpu/drm/msm/msm_mmu.h   |  1 +
>  2 files changed, 29 insertions(+)
> 
> diff --git a/drivers/gpu/drm/msm/msm_iommu.c b/drivers/gpu/drm/msm/msm_iommu.c
> index a79cd18bc4c9..3d5c1bb4c013 100644
> --- a/drivers/gpu/drm/msm/msm_iommu.c
> +++ b/drivers/gpu/drm/msm/msm_iommu.c
> @@ -343,6 +343,19 @@ static int msm_gpu_fault_handler(struct iommu_domain *domain, struct device *dev
>  	return 0;
>  }
>  
> +static int msm_disp_fault_handler(struct iommu_domain *domain, struct device *dev,
> +				  unsigned long iova, int flags, void *arg)
> +{
> +	struct msm_iommu *iommu = arg;
> +
> +	if (iommu->base.handler)
> +		return iommu->base.handler(iommu->base.arg, iova, flags, NULL);
> +
> +	pr_warn_ratelimited("*** fault: iova=%16lx, flags=%d\n", iova, flags);
> +
> +	return 0;

I'd say, drop pr_warn and return -ENOSYS, letting the
arm_smmu_context_fault() report the error.

> +}
> +
>  static void msm_iommu_resume_translation(struct msm_mmu *mmu)
>  {
>  	struct adreno_smmu_priv *adreno_smmu = dev_get_drvdata(mmu->dev);
> @@ -434,6 +447,21 @@ struct msm_mmu *msm_iommu_new(struct device *dev, unsigned long quirks)
>  	return &iommu->base;
>  }
>  
> +struct msm_mmu *msm_iommu_disp_new(struct device *dev, unsigned long quirks)
> +{
> +	struct msm_iommu *iommu;
> +	struct msm_mmu *mmu;
> +
> +	mmu = msm_iommu_new(dev, quirks);
> +	if (IS_ERR_OR_NULL(mmu))
> +		return mmu;
> +
> +	iommu = to_msm_iommu(mmu);
> +	iommu_set_fault_handler(iommu->domain, msm_disp_fault_handler, iommu);
> +
> +	return mmu;
> +}
> +
>  struct msm_mmu *msm_iommu_gpu_new(struct device *dev, struct msm_gpu *gpu, unsigned long quirks)
>  {
>  	struct adreno_smmu_priv *adreno_smmu = dev_get_drvdata(dev);
> diff --git a/drivers/gpu/drm/msm/msm_mmu.h b/drivers/gpu/drm/msm/msm_mmu.h
> index 88af4f490881..730458d08d6b 100644
> --- a/drivers/gpu/drm/msm/msm_mmu.h
> +++ b/drivers/gpu/drm/msm/msm_mmu.h
> @@ -42,6 +42,7 @@ static inline void msm_mmu_init(struct msm_mmu *mmu, struct device *dev,
>  
>  struct msm_mmu *msm_iommu_new(struct device *dev, unsigned long quirks);
>  struct msm_mmu *msm_iommu_gpu_new(struct device *dev, struct msm_gpu *gpu, unsigned long quirks);
> +struct msm_mmu *msm_iommu_disp_new(struct device *dev, unsigned long quirks);
>  
>  static inline void msm_mmu_set_fault_handler(struct msm_mmu *mmu, void *arg,
>  		int (*handler)(void *arg, unsigned long iova, int flags, void *data))
> -- 
> 2.44.0
> 

-- 
With best wishes
Dmitry