From mboxrd@z Thu Jan  1 00:00:00 1970
From: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>
Subject: Re: [PATCH v4] devicetree: Add generic IOMMU device tree bindings
Date: Wed, 9 Jul 2014 14:40:50 +0100
Message-ID: <20140709134050.GN9485@arm.com>
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Cc: Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Pawel Moll <Pawel.Moll-5wv7dgnIgG8@public.gmane.org>, Mark Rutland <Mark.Rutland-5wv7dgnIgG8@public.gmane.org>, Ian Campbell <ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org>, Kumar Gala <galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>, Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>, Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>, Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>, Cho KyongHo <pullip.cho-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>, Grant Grundler <grundler-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>, Dave P Martin <Dave.Martin-5wv7dgnIgG8@public.gmane.org>, Marc Zyngier <Marc.Zyngier-5wv7dgnIgG8@public.gmane.org>, Hiroshi Doyu <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>, Olav Haugan <ohaugan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>, Varun Sethi <varun.sethi-KZfg59tc24xl57MIdRCFDg@public.gmane.org>, "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" <iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>, "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" <linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>, "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <linux-kernel-u79uwXL29TZNg+MwTxZMZA@public.gmane.org>
List-Id: devicetree@vger.kernel.org

On Fri, Jul 04, 2014 at 04:29:17PM +0100, Thierry Reding wrote:
> From: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> 
> This commit introduces a generic device tree binding for IOMMU devices.
> Only a very minimal subset is described here, but it is enough to cover
> the requirements of both the Exynos System MMU and Tegra SMMU as
> discussed here:
> 
>     https://lkml.org/lkml/2014/4/27/346
> 
> Signed-off-by: Thierry Reding <treding-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

  Acked-by: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>

I would like to move the ARM SMMU driver over to this for 3.18, if possible.
One use-case there is the ability to describe groups of masters behind a
multi-master IOMMU but which must be part of the same domain (i.e. an
iommu_group). This is useful for presenting devices to a guest with a
virtual SMMU, where the physical devices share a stage-2 context.

With your binding, does this simply mean determining the set of master IDs
in the group, then describing the complete set for each master?

Will