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SubjectRe: [v4,0/3] iommu/ipmmu-vmsa: r8a7796 support V4

Hi, Magnus, maintainers, all.

On 19.06.17 14:04, Magnus Damm wrote:
> iommu/ipmmu-vmsa: r8a7796 support V4
> [PATCH v4 1/3] iommu/ipmmu-vmsa: Add r8a7796 DT binding
> [PATCH v4 2/3] iommu/ipmmu-vmsa: Increase maximum micro-TLBS to 48
> [PATCH v4 3/3] iommu/ipmmu-vmsa: Hook up r8a7796 DT matching code
> This series adds r8a7796 support to the IPMMU driver. The DT binding
> gets updated, maximum number of micro-TLBs are increased and the
> driver is adjusted to match on the new DT binding.
I am interested in adding IPMMU-VMSA support to Xen hypervisor.

I did some preparations for making IPMMU-VMSA to feel comfortable [1]
inside Xen
followed by direct porting Linux IPMMU-VMSA driver and ARM LPAE
page-table allocator [2] to it.

I decided to base on the "BSP" driver [3] because it had more complete
support than the "mainline" one [4].

During review I got a feedback that "BSP" driver wasn't the best choice
to be ported.
Xen ARM maintainers worry about "BSP" driver which haven't had a
thorough review by the Linux community and as the result might have bugs
which will never be fixed, etc.

So, for the IPMMU-VMSA support to be accepted by Xen community I should
either write our own driver based on BSP/mainline/whatever which
contains only relevant to Xen things or
direct port from "mainline" driver. As the second option relies on the
required support [5] which isn't in mainline yet, it is not clear when
this support gets merged and how it will be modified/reworked before,
we preliminarily decided to follow the first option. But, I would like
to consider second option again. Despite the complexity of second
option, it has one significant benefit.

I see that Linux driver is being developed quite actively and looking
over all related patch series I got a feeling that required support was
about to reach upstream.

Could you, please, clarify some questions which, I hope, help us to make
a decision:
1. Do you have approximate time-frame for getting this support in?
2. Are fundamental/significant changes planned for this support?

Also, may I ask for a link to github branch which contains current (and
likely r8a7795 and 32-bit ARM update) patch series?

Thank you in advance!

And sorry for the most likely incorrect format of this email.

> Changes since V3:
> - Rebased on top of [PATCH v4 00/09] iommu/ipmmu-vmsa: r8a7795 support V4
> - Patch 3/3 updated with Reviewed-by - thanks Geert!
> Changes since V2:
> - Patch 2/3 updated with an outer set of () - thanks Ramesh!
> - Patch 2/3 updated with Reviewed-by - thanks Geert!
> - Patch 3/3 updated to include white list support
> Changes since V1:
> - Patch 1/3 updated with more Acked-by tags
> - Patch 2/3 updated with high I/O register range support
> Patch 1/3 is ready for upstream merge and includes the following tags:
> Signed-off-by: Magnus Damm <>
> Acked-by: Laurent Pinchart <>
> Acked-by: Rob Herring <>
> Acked-by: Simon Horman <>
> Acked-by: Geert Uytterhoeven <>
> Patch 2/3 and 3/3 are quite trivial but have no acked-by so far.
> Signed-off-by: Magnus Damm <>
> ---
> Developed on top of next-20170614 with the following series applied
> [PATCH 00/04] iommu/ipmmu-vmsa: 32-bit ARM update
> [PATCH v4 00/09] iommu/ipmmu-vmsa: r8a7795 support V4
> Documentation/devicetree/bindings/iommu/renesas,ipmmu-vmsa.txt | 1
> drivers/iommu/ipmmu-vmsa.c | 24 +++++++---
> 2 files changed, 18 insertions(+), 7 deletions(-)

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