Message-ID: <5A57471E.7020304@rock-chips.com>
Date: Thu, 11 Jan 2018 19:14:38 +0800
From: JeffyChen <jeffy.chen@rock-chips.com>
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To: Marek Szyprowski <m.szyprowski@samsung.com>,
        linux-kernel@vger.kernel.org
CC: jcliang@chromium.org, robin.murphy@arm.com, tfiga@chromium.org,
        linux-samsung-soc@vger.kernel.org, Kukjin Kim <kgene@kernel.org>,
        devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        iommu@lists.linux-foundation.org,
        Frank Rowand <frowand.list@gmail.com>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Rob Clark <robdclark@gmail.com>,
        Will Deacon <will.deacon@arm.com>,
        Joerg Roedel <joro@8bytes.org>,
        Rob Herring <robh+dt@kernel.org>,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/9] iommu/of: Drop early initialisation hooks
References: <20180111082229.24011-1-jeffy.chen@rock-chips.com> <CGME20180111082537epcas3p274f6bfeb31f10742e8129dc0c877745e@epcas3p2.samsung.com> <20180111082229.24011-2-jeffy.chen@rock-chips.com> <60fdd375-ca74-0fea-c598-39a68b9e7735@samsung.com>
In-Reply-To: <60fdd375-ca74-0fea-c598-39a68b9e7735@samsung.com>
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Sender: linux-kernel-owner@vger.kernel.org

Hi Marek,

Thanks for your reply.

On 01/11/2018 05:40 PM, Marek Szyprowski wrote:
> Hi Jeffy,
>
> On 2018-01-11 09:22, Jeffy Chen wrote:
>> With the probe-deferral mechanism, early initialisation hooks are no
>> longer needed.
>>
>> Suggested-by: Robin Murphy <robin.murphy@arm.com>
>> Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
>> ---
>>
>>   drivers/iommu/arm-smmu-v3.c  |  2 +-
>>   drivers/iommu/arm-smmu.c     | 12 ++++++------
>>   drivers/iommu/exynos-iommu.c |  2 +-
>
> For Exynos IOMMU:
> Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
>
> IPMMU and MSM IOMMU are no longer multi-platform safe after this patch.
> It breaks them in the same way as my commit 928055a01b3f ("iommu/exynos:
> Remove custom platform device registration code") broke Exynos IOMMU.
>
> You need a similar fix for them:
> https://www.spinics.net/lists/arm-kernel/msg627648.html

hmmm, right, i did saw this fix in the rockchip iommu driver too.

and there're also some other iommu drivers put bus_set_iommu in their 
probe() to avoid that.

maybe we can do it in the iommu framework?

for example:
1/ add a bus type member to struct iommu_device
2/ and a iommu_device_set_bus()
3/ do the bus_set_iommu stuff in iommu_device_register()
4/ undo bus_set_iommu in iommu_device_unregister()