Date: Thu, 6 Jul 2017 16:10:45 +0200
From: Christoph Hellwig <hch@lst.de>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Tomasz Figa <tfiga@chromium.org>,
        "open list:IOMMU DRIVERS" <iommu@lists.linux-foundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Christoph Hellwig <hch@lst.de>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Joerg Roedel <joro@8bytes.org>, Will Deacon <will.deacon@arm.com>,
        Vineet Gupta <vgupta@synopsys.com>,
        Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>,
        Mitchel Humpherys <mitchelh@codeaurora.org>,
        Krzysztof Kozlowski <krzk@kernel.org>, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [RFC PATCH 4/5] iommu/dma: Export non-static functions to use
        in modules
Message-ID: <20170706141045.GA577@lst.de>
References: <20170705071215.17603-1-tfiga@chromium.org> <20170705071215.17603-5-tfiga@chromium.org> <d02d47f2-8e89-ddba-54d9-1d1f52ae394a@arm.com> <CAAFQd5C3P7Rpohq=5xoBs1mUtbQ63FbQ80-Rm08JEY-iDyipYA@mail.gmail.com> <f66b6ebc-9977-8783-4e6a-10dcfcadf60d@arm.com>
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On Thu, Jul 06, 2017 at 12:09:45PM +0100, Robin Murphy wrote:
> I suppose another option is to just make the IOMMU and DMA ops a
> self-contained non-modular driver mirroring the VT-d/AMD-Vi IOMMUs -
> AFAICS it shouldn't have to be all that tightly coupled to the IPU bus
> code, the latter more or less just needs to create the appropriate IOMMU
> device for the driver to find.

I still haven't seen the driver code, but this seems to be best
solution so far.  Given that it's not a plug in device but part of
an SOC that seems perfectly acceptable to me.