Re: [PATCHv3 4/6] iommu/arm-smmu-qcom: Request direct mapping for modem device

[Robin Murphy]

On 2020-04-20 5:42 pm, Sai Prakash Ranjan wrote:
> From: Sibi Sankar <sibis@xxxxxxxxxxxxxx>
>
> Request direct mapping for modem on platforms which don't have TrustZone
> (which programs the modem SIDs) to prevent the following global faults seen
> on Cheza/Trogdor:

Not strictly true - it's patch #6/6 that prevents *those* faults (and 
these days the driver should be reporting unmatched streams a little 
more helpfully). This change would resolve the context faults and/or 
weird memory corruption that might result from applying patch #6 alone - 
this is the crazy thing where transactions sometimes go directly to DRAM 
round the side of the SMMU so we can never safely remap anything, right?

Robin.

> arm-smmu 15000000.iommu: Unexpected global fault, this could be serious
> arm-smmu 15000000.iommu: GFSR 0x80000002, GFSYNR0 0x00000000,
> 			 GFSYNR1 0x00000781, GFSYNR2 0x00000000
>
> arm-smmu 15000000.iommu: Unexpected global fault, this could be serious
> arm-smmu 15000000.iommu: GFSR 0x80000002, GFSYNR0 0x00000000,
> 			 GFSYNR1 0x00000461, GFSYNR2 0x00000000
>
> Signed-off-by: Sibi Sankar <sibis@xxxxxxxxxxxxxx>
> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
> ---
>   drivers/iommu/arm-smmu-qcom.c | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/drivers/iommu/arm-smmu-qcom.c b/drivers/iommu/arm-smmu-qcom.c
> index 5bedf21587a5..cf01d0215a39 100644
> --- a/drivers/iommu/arm-smmu-qcom.c
> +++ b/drivers/iommu/arm-smmu-qcom.c
> @@ -17,7 +17,9 @@ static const struct of_device_id qcom_smmu_client_of_match[] = {
>   	{ .compatible = "qcom,mdp4" },
>   	{ .compatible = "qcom,mdss" },
>   	{ .compatible = "qcom,sc7180-mdss" },
> +	{ .compatible = "qcom,sc7180-mss-pil" },
>   	{ .compatible = "qcom,sdm845-mdss" },
> +	{ .compatible = "qcom,sdm845-mss-pil" },
>   	{ }
>   };
>