[RFC PATCH 04/30] iommu/arm-smmu-v3: Add support for PCI ATS

[Sinan Kaya]

On 2/27/2017 2:54 PM, Jean-Philippe Brucker wrote:
> /* Initialise command lazily */
> +		if (!cmd.opcode)
> +			arm_smmu_atc_invalidate_to_cmd(smmu, iova, size, &cmd);
> +
> +		spin_lock(&smmu_group->devices_lock);
> +
> +		list_for_each_entry(master, &smmu_group->devices, group_head)
> +			arm_smmu_atc_invalidate_master(master, &cmd);
> +
> +		/*
> +		 * TODO: ensure we do a sync whenever we have sent ats_queue_depth
> +		 * invalidations to the same device.
> +		 */
> +		arm_smmu_cmdq_issue_cmd(smmu, &sync_cmd);
> +

It is possible to observe ATS invalidation timeout up to 90 seconds according to PCIe
spec. How does the current code deal with this?

-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.