From: Marek Szyprowski <m.szyprowski@samsung.com>
To: JeffyChen <jeffy.chen@rock-chips.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
Date: Thu, 11 Jan 2018 13:26:26 +0100 [thread overview]
Message-ID: <ad520247-8342-97c2-4448-5f5e87394aa1@samsung.com> (raw)
In-Reply-To: <5A57471E.7020304@rock-chips.com>
Hi Jeffy,
On 2018-01-11 12:14, JeffyChen wrote:
> 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()
Frankly, in case the device-tree based systems bus_set_iommu()
should not be needed at all. However for some legacy reasons it
is still required by a few bits of code (at least it was needed
some time ago). Probably it would be best if this is finally
resolved.
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
prev parent reply other threads:[~2018-01-11 12:26 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-11 8:22 [PATCH 0/9] iommu/rockchip: Use OF_IOMMU Jeffy Chen
2018-01-11 8:22 ` [PATCH 1/9] iommu/of: Drop early initialisation hooks Jeffy Chen
[not found] ` <20180111082229.24011-2-jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2018-01-11 9:40 ` Marek Szyprowski
[not found] ` <60fdd375-ca74-0fea-c598-39a68b9e7735-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2018-01-11 11:14 ` JeffyChen
[not found] ` <5A57471E.7020304-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2018-01-11 12:24 ` Robin Murphy
[not found] ` <faeccc75-79e9-ddb6-446d-88ab63fe4e1f-5wv7dgnIgG8@public.gmane.org>
2018-01-12 1:22 ` JeffyChen
2018-01-11 12:26 ` Marek Szyprowski [this message]
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