From: m.szyprowski@samsung•com (Marek Szyprowski)
To: linux-arm-kernel@lists•infradead.org
Subject: [RFC PATCH v3 5/7] dma-mapping: detect and configure IOMMU in of_dma_configure
Date: Mon, 27 Oct 2014 12:12:38 +0100 [thread overview]
Message-ID: <544E28A6.8090209@samsung.com> (raw)
In-Reply-To: <20141027105158.GE8768@arm.com>
Hello,
On 2014-10-27 11:51, Will Deacon wrote:
> On Tue, Oct 14, 2014 at 01:53:59PM +0100, Laurent Pinchart wrote:
>> On Monday 22 September 2014 18:50:27 Will Deacon wrote:
>>> On Mon, Sep 22, 2014 at 10:29:10AM +0100, Thierry Reding wrote:
>>>> Agreed. I wonder how useful it is to know the set of IOMMU instances
>>>> that each device can master through. Wouldn't it be more useful to keep
>>>> a list of master interfaces for each device? The set of IOMMU instances
>>>> can trivially be derived from that.
>>> I'm struggling to think how that would look. What do you mean by `master
>>> interfaces' in terms of the code we have in Linux? At the end of the day,
>>> the list of IOMMU instances (i.e. iommu_dma_mapping) exists because you
>>> and Laurent have use-cases involving devices mastering through multiple
>>> IOMMUs. If it doesn't work for you, it might be best for you to send me
>>> the patch ;)
>> Just for the record, I've brought up the topic of masters being served by
>> multiple IOMMUs, but don't have a use case for it (yet at least). I do have
>> masters served through multiple streams with separate stream IDs, but all by
>> the same IOMMU.
> Ok. I spoke to Arnd, David and Joerg at LPC and the consensus was that the
> DMA-mapping API should *not* be exposed to the details of masters that
> master through multiple IOMMUs. Instead, that should be abstracted by the
> device API by exposing that device as a single struct device.
>
> So, that's certainly an area that needs more work and I'll drop the limited
> support I'd cooked up from this patch set in the next version.
Great! That's more or less something I've already implemented on top of your
previous patchset, as I didn't have any good idea how to manage multiple
masters
separately. I'm waiting for your next update and I will rebase my
patches soon.
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
next prev parent reply other threads:[~2014-10-27 11:12 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-12 16:34 [RFC PATCH v3 0/7] Introduce automatic DMA configuration for IOMMU masters Will Deacon
2014-09-12 16:34 ` [RFC PATCH v3 1/7] iommu: provide early initialisation hook for IOMMU drivers Will Deacon
2014-09-18 14:31 ` Robin Murphy
2014-09-22 17:35 ` Will Deacon
2014-09-12 16:34 ` [RFC PATCH v3 2/7] dma-mapping: replace set_arch_dma_coherent_ops with arch_setup_dma_ops Will Deacon
2014-09-12 16:34 ` [RFC PATCH v3 3/7] iommu: add new iommu_ops callback for adding an OF device Will Deacon
2014-09-15 11:57 ` Marek Szyprowski
2014-09-17 1:39 ` Will Deacon
2014-09-12 16:34 ` [RFC PATCH v3 4/7] iommu: provide helper function to configure an IOMMU for an of master Will Deacon
2014-09-18 11:13 ` Laurent Pinchart
2014-09-22 17:13 ` Will Deacon
2014-10-14 13:12 ` Laurent Pinchart
2014-09-12 16:34 ` [RFC PATCH v3 5/7] dma-mapping: detect and configure IOMMU in of_dma_configure Will Deacon
2014-09-18 11:17 ` Laurent Pinchart
2014-09-22 9:29 ` Thierry Reding
2014-09-22 17:50 ` Will Deacon
2014-10-14 12:53 ` Laurent Pinchart
2014-10-27 10:51 ` Will Deacon
2014-10-27 11:12 ` Marek Szyprowski [this message]
2014-10-27 11:30 ` Laurent Pinchart
2014-10-27 16:02 ` Will Deacon
2014-10-27 16:33 ` jroedel at suse.de
2014-09-22 17:46 ` Will Deacon
2014-09-12 16:34 ` [RFC PATCH v3 6/7] arm: call iommu_init before of_platform_populate Will Deacon
2014-09-22 9:36 ` Thierry Reding
2014-09-22 11:08 ` Arnd Bergmann
2014-09-22 11:40 ` Thierry Reding
2014-09-22 16:03 ` Arnd Bergmann
2014-09-23 7:02 ` Thierry Reding
2014-09-23 7:44 ` Arnd Bergmann
2014-09-23 8:59 ` Thierry Reding
2014-10-14 13:07 ` Laurent Pinchart
2014-10-14 13:20 ` Arnd Bergmann
2014-10-14 13:37 ` Thierry Reding
2014-10-14 15:01 ` Laurent Pinchart
2014-10-14 15:05 ` Thierry Reding
2014-10-14 15:10 ` Laurent Pinchart
2014-09-12 16:34 ` [RFC PATCH v3 7/7] arm: dma-mapping: plumb our iommu mapping ops into arch_setup_dma_ops Will Deacon
2014-09-22 9:19 ` Thierry Reding
2014-09-22 9:22 ` Laurent Pinchart
2014-09-22 17:43 ` Will Deacon
2014-09-23 7:14 ` Thierry Reding
2014-09-24 16:33 ` Will Deacon
2014-09-25 6:40 ` Thierry Reding
2014-09-30 16:00 ` Will Deacon
2014-10-01 8:46 ` Thierry Reding
2014-10-03 15:08 ` Will Deacon
2014-10-06 9:52 ` Thierry Reding
2014-10-06 10:50 ` Laurent Pinchart
2014-10-06 13:05 ` Thierry Reding
2014-09-16 11:40 ` [RFC PATCH v3 0/7] Introduce automatic DMA configuration for IOMMU masters Robin Murphy
2014-09-17 1:19 ` Will Deacon
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