[RFC,20/30] iommu/arm-smmu-v3: Enable PCI PASID in masters

Sinan Kaya
2017-06-23T14:39:06Z

Hi Jean-Philippe,

> On 2/27/2017 2:54 PM, Jean-Philippe Brucker wrote:
> Enable PASID for PCI devices that support it.
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
> ---
> drivers/iommu/arm-smmu-v3.c | 66 ++++++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 63 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index 499dc1cd07eb..37fd061405e9 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -730,6 +730,8 @@ struct arm_smmu_master_data {
>
> struct arm_smmu_stream *streams;
> struct rb_root contexts;
> +
> + u32 avail_contexts;
> };
>

According to the PASID ECN here (https://pcisig.com/sites/default/files/specification_documents/ECN-PASID-ATS-2011-03-31.pdf),
PASID should be enabled only if all switches between the root port and
a device support TLP prefix.

I'm only seeing a call to pci_enable_pasid() in this patch but I don't
see anybody checking for TLP prefix support on the hierarchy.

This could potentially be an addition to the PCI core code.

Sinan

--
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.