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Message-ID: <20140517204805.GA1046@mithrandir>
Date: Sat, 17 May 2014 22:48:06 +0200
From: Thierry Reding <thierry.reding@...il.com>
To: Cho KyongHo <pullip.cho@...sung.com>
Cc: Rob Herring <robh+dt@...nel.org>, Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
Arnd Bergmann <arnd@...db.de>,
Grant Grundler <grundler@...omium.org>,
Dave Martin <Dave.Martin@....com>,
Marc Zyngier <marc.zyngier@....com>,
Will Deacon <will.deacon@....com>,
Joerg Roedel <joro@...tes.org>,
Stephen Warren <swarren@...dotorg.org>,
devicetree@...r.kernel.org, iommu@...ts.linux-foundation.org,
linux-arm-kernel@...ts.infradead.org, linux-tegra@...r.kernel.org,
linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] devicetree: Add generic IOMMU device tree bindings
On Sat, May 17, 2014 at 05:04:55PM +0900, Cho KyongHo wrote:
> On Fri, 16 May 2014 14:23:18 +0200, Thierry Reding wrote:
[...]
> > +Examples:
> > +=========
> > +
> > +Single-master IOMMU:
> > +--------------------
> > +
> > + iommu {
> > + #iommu-cells = <0>;
> > + };
> > +
> > + master {
> > + iommu = <&/iommu>;
> > + };
> > +
>
> Great work, Thierry.
>
> One simple comment.
>
> This should be also applicable to multi-master IOMMUs that the masters
> of an IOMMU is not configurable with ID or something.
> I think the title needs to be changed to cover such IOMMUs which always
> translate master's transactions and unable to change the configuration
> of the relationship between the masters and IOMMUs by S/W.
Agreed, how about we add a separate example for that case:
Multiple-master IOMMU with fixed associations:
----------------------------------------------
/* multiple-master IOMMU */
iommu {
/*
* Masters are statically associated with this IOMMU and
* address translation is always enabled.
*/
#iommu-cells = <0>;
};
/* static association with IOMMU */
master@1 {
reg = <1>;
iommus = <&/iommu>;
};
/* static association with IOMMU */
master@2 {
reg = <2>;
iommus = <&/iommu>;
};
?
Thierry
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