[PATCH v2] iommu: arm-smmu-qcom: Ensure smmu is powered up in set_ttbr0_cfg

[Xilin Wu]

On 3/26/2026 5:11 AM, Anna Maniscalco wrote:
> Previously the device was being accessed while potentially in a
> suspended state.
> 
> Signed-off-by: Anna Maniscalco <anna.maniscalco2000 at gmail.com>
> ---
> Changes in v2:
> - Simplify patch by acquiring device just around the call that needs it
> - Link to v1: https://lore.kernel.org/r/20260210-qcom_smmu_pmfix-v1-1-78b7143ac053@gmail.com
> ---
>   drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> index 573085349df3..cab7d110aaf5 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> @@ -231,6 +231,7 @@ static int qcom_adreno_smmu_set_ttbr0_cfg(const void *cookie,
>   	struct io_pgtable *pgtable = io_pgtable_ops_to_pgtable(smmu_domain->pgtbl_ops);
>   	struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
>   	struct arm_smmu_cb *cb = &smmu_domain->smmu->cbs[cfg->cbndx];
> +	int ret;
>   
>   	/* The domain must have split pagetables already enabled */
>   	if (cb->tcr[0] & ARM_SMMU_TCR_EPD1)
> @@ -260,8 +261,16 @@ static int qcom_adreno_smmu_set_ttbr0_cfg(const void *cookie,
>   		cb->ttbr[0] |= FIELD_PREP(ARM_SMMU_TTBRn_ASID, cb->cfg->asid);
>   	}
>   
> +	ret = pm_runtime_resume_and_get(smmu_domain->smmu->dev);
> +	if (ret < 0) {
> +		dev_err(smmu_domain->smmu->dev, "failed to get runtime PM: %d\n", ret);
> +		return -ENODEV;
> +	}
> +
>   	arm_smmu_write_context_bank(smmu_domain->smmu, cb->cfg->cbndx);
>   
> +	pm_runtime_put_autosuspend(smmu_domain->smmu->dev);
> +
>   	return 0;
>   }
>   
> 
> ---
> base-commit: 50c4a49f7292b33b454ea1a16c4f77d6965405dc
> change-id: 20260210-qcom_smmu_pmfix-2aead2ba4e20
> 
> Best regards,

May I ask what is the status of this patch? Without this patch, I can 
trigger a crash easily on sc8280xp by running fastfetch multiple times.

Tested-by: Xilin Wu <sophon at radxa.com> # sc8280xp-radxa-dragon-q8b

-- 
Best regards,
Xilin Wu <sophon at radxa.com>