From mboxrd@z Thu Jan  1 00:00:00 1970
From: joro@8bytes.org (Joerg Roedel)
Date: Fri, 21 Jun 2013 15:55:08 +0200
Subject: [PATCH 7/9] documentation: iommu: add description of ARM System
 MMU binding
In-Reply-To: <20130621095729.GA7766@mudshark.cambridge.arm.com>
References: <1370889285-22799-1-git-send-email-will.deacon@arm.com>
 <1370889285-22799-8-git-send-email-will.deacon@arm.com>
 <20130620200845.GF11309@8bytes.org>
 <20130621095729.GA7766@mudshark.cambridge.arm.com>
Message-ID: <20130621135507.GI11309@8bytes.org>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Hi Will,

On Fri, Jun 21, 2013 at 10:57:29AM +0100, Will Deacon wrote:
> This is a common driver that will support any IOMMUs compatible with v1 or
> v2 of the ARM SMMU architecture. Currently, that includes SMMUs known
> informatively as MMU-400, MMU-401 and MMU-500. I had a look at the other
> IOMMU drivers in the kernel and they seem to be driving incompatible IOMMUs,
> so I don't see how this driver can replace those.
> 
> However, we'll hopefully see ARM SMMU-compatible devices turning up soon (I
> know of many SoCs in development that are looking at them).

That sounds great. So in the future there will be a single driver for
most future SOCs. This is a real improvement over the current situation.

>>From NVidia is another driver with 'smmu' in its name, is that one also
incompatible?

> Chaining is really horrible and exists as a hack to support virtualisation
> using two separate SMMUs, where neither of them can support nested
> translation.

I see, thanks for the explanation.


	Joerg