On Thu 13 Aug 21:41 CDT 2020, Rob Clark wrote:

> From: Rob Clark <robdcl...@chromium.org>
> 
> For the Adreno GPU's SMMU, we want SCTLR.HUPCF set to ensure that
> pending translations are not terminated on iova fault.  Otherwise
> a terminated CP read could hang the GPU by returning invalid
> command-stream data.
> 

Reviewed-by: Bjorn Andersson <bjorn.anders...@linaro.org>

> Signed-off-by: Rob Clark <robdcl...@chromium.org>
> ---
>  drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 6 ++++++
>  drivers/iommu/arm/arm-smmu/arm-smmu.c      | 3 +++
>  drivers/iommu/arm/arm-smmu/arm-smmu.h      | 3 +++
>  3 files changed, 12 insertions(+)
> 
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c 
> b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> index 5640d9960610..2aa6249050ff 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> @@ -127,6 +127,12 @@ static int qcom_adreno_smmu_init_context(struct 
> arm_smmu_domain *smmu_domain,
>           (smmu_domain->cfg.fmt == ARM_SMMU_CTX_FMT_AARCH64))
>               pgtbl_cfg->quirks |= IO_PGTABLE_QUIRK_ARM_TTBR1;
>  
> +     /*
> +      * On the GPU device we want to process subsequent transactions after a
> +      * fault to keep the GPU from hanging
> +      */
> +     smmu_domain->cfg.sctlr_set |= ARM_SMMU_SCTLR_HUPCF;
> +
>       /*
>        * Initialize private interface with GPU:
>        */
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c 
> b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> index e63a480d7f71..bbec5793faf8 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> @@ -617,6 +617,9 @@ void arm_smmu_write_context_bank(struct arm_smmu_device 
> *smmu, int idx)
>       if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
>               reg |= ARM_SMMU_SCTLR_E;
>  
> +     reg |= cfg->sctlr_set;
> +     reg &= ~cfg->sctlr_clr;
> +
>       arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_SCTLR, reg);
>  }
>  
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h 
> b/drivers/iommu/arm/arm-smmu/arm-smmu.h
> index cd75a33967bb..2df3a70a8a41 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.h
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h
> @@ -144,6 +144,7 @@ enum arm_smmu_cbar_type {
>  #define ARM_SMMU_CB_SCTLR            0x0
>  #define ARM_SMMU_SCTLR_S1_ASIDPNE    BIT(12)
>  #define ARM_SMMU_SCTLR_CFCFG         BIT(7)
> +#define ARM_SMMU_SCTLR_HUPCF         BIT(8)
>  #define ARM_SMMU_SCTLR_CFIE          BIT(6)
>  #define ARM_SMMU_SCTLR_CFRE          BIT(5)
>  #define ARM_SMMU_SCTLR_E             BIT(4)
> @@ -341,6 +342,8 @@ struct arm_smmu_cfg {
>               u16                     asid;
>               u16                     vmid;
>       };
> +     u32                             sctlr_set;    /* extra bits to set in 
> SCTLR */
> +     u32                             sctlr_clr;    /* bits to mask in SCTLR 
> */
>       enum arm_smmu_cbar_type         cbar;
>       enum arm_smmu_context_fmt       fmt;
>  };
> -- 
> 2.26.2
> 
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