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From:   Chunyan Zhang <zhang.lyra@gmail.com>
Date:   Wed, 3 Feb 2021 09:49:43 +0800
Message-ID: <CAAfSe-s9ppQBuM81KB_KWaiY5hz3cFAycFP5jd8JXysicoqFGw@mail.gmail.com>
Subject: Re: [PATCH 2/2] iommu: add Unisoc iommu basic driver
To:     Robin Murphy <robin.murphy@arm.com>
Cc:     Joerg Roedel <joro@8bytes.org>, DTML <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Chunyan Zhang <chunyan.zhang@unisoc.com>,
        Sheng Xu <sheng.xu@unisoc.com>,
        Linux IOMMU <iommu@lists.linux-foundation.org>,
        Rob Herring <robh+dt@kernel.org>,
        Baolin Wang <baolin.wang7@gmail.com>,
        Orson Zhai <orsonzhai@gmail.com>
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On Wed, 3 Feb 2021 at 02:02, Robin Murphy <robin.murphy@arm.com> wrote:
>
> On 2021-02-02 14:41, Joerg Roedel wrote:
> > On Tue, Feb 02, 2021 at 02:34:34PM +0000, Robin Murphy wrote:
> >> Nope, I believe if Arm Ltd. had any involvement in this I'd know about it :)
> >
> > Okay, got confused by thinking of ARM as the CPU architecture, not the
> > company :)
> > But given the intel/ and amd/ subdirectories refer to company names as
> > well, the same is true for arm/.
>
> Right, trying to group IOMMU drivers by supposed CPU architecture is
> already a demonstrable non-starter; does intel-iommu count as x86, or
> IA-64, or do you want two copies? :P
>
> I somehow doubt anyone would license one of Arm's SMMUs to go in a
> RISC-V/MIPS/etc. based SoC, but in principle, they *could*. In fact it's
> precisely cases like this one - where silicon vendors come up with their
> own little scatter-gather unit to go with their own display controller
> etc. - that I imagine are most likely to get reused if the vendor
> decides to experiment with different CPUs to reach new market segments.

Yes, I agree, I believe this iommu unit along with Unisoc's
multi-media modules can be used on other architecture SoCs, not only
ARM based.

>
> Robin.