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Message-ID: <cc7c13c2-df5c-68bf-a4b6-e46df64db1c3@linaro.org>
Date:   Fri, 4 Nov 2022 09:46:54 -0400
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Subject: Re: [PATCH v2 3/6] iommu/exynos: Modularize the driver
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To:     Sam Protsenko <semen.protsenko@linaro.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>
Cc:     Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Alim Akhtar <alim.akhtar@samsung.com>,
        Janghyuck Kim <janghyuck.kim@samsung.com>,
        Cho KyongHo <pullip.cho@samsung.com>,
        Daniel Mentz <danielmentz@google.com>,
        David Virag <virag.david003@gmail.com>, iommu@lists.linux.dev,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-samsung-soc@vger.kernel.org
References: <20221103195154.21495-1-semen.protsenko@linaro.org>
 <20221103195154.21495-4-semen.protsenko@linaro.org>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <20221103195154.21495-4-semen.protsenko@linaro.org>
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On 03/11/2022 15:51, Sam Protsenko wrote:
> Rework the driver so it can be built as a loadable module. That can be
> useful as not all ARM64 platforms need it. And that's ok for it to be a
> module because it's not a critical driver (platform can work when it's
> disabled).
> 
> Remove method and module exit function are not implemented, as the
> removal of IOMMUs cannot be done reliably. As Robin Murphy mentioned in
> [1]:
> 
>     ...it's better not to even pretend that removing an IOMMU's driver
>     while other drivers are using it (usually via DMA ops without even
>     realising) is going to have anything other than catastrophic
>     results.
> 
> [1] https://lore.kernel.org/lkml/20220702213724.3949-2-semen.protsenko@linaro.org/T/#md7e1e3f5b2c9e7fa5bc28fe33e818b6aa4a7237c
> 
> Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>


Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof