From: m.szyprowski@samsung•com (Marek Szyprowski)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v6 1/8] iommu: provide early initialisation hook for IOMMU drivers
Date: Fri, 05 Dec 2014 14:49:01 +0100 [thread overview]
Message-ID: <5481B7CD.80106@samsung.com> (raw)
In-Reply-To: <20141205131815.GA18747@ulmo.nvidia.com>
Hello,
On 2014-12-05 14:18, Thierry Reding wrote:
> On Fri, Dec 05, 2014 at 01:06:52PM +0000, Grant Likely wrote:
>> On Fri, Dec 5, 2014 at 12:35 PM, Robin Murphy <robin.murphy@arm•com> wrote:
>>> Hi Will,
>>>
>>> On 05/12/14 12:10, Will Deacon wrote:
>>> [...]
>>>>>> Do you expect drivers to modify that *priv pointer after the ops
>>>>>> structure is registered? I'd be very surprised if that was the use
>>>>>> case. It's fine for the driver to register a non-const version, but
>>>>>> once it is registered, the infrastructure can treat it as const from
>>>>>> then on.
>>>>>
>>>>> Possibly not - certainly my current port of the ARM SMMU which makes use
>>>>> of *priv is only ever reading it - although we did also wave around
>>>>> reasons for mutable ops like dynamically changing the pgsize_bitmap and
>>>>> possibly even swizzling individual ops for runtime reconfiguration. On
>>>>> consideration though, I'd agree that things like that are mad enough to
>>>>> stay well within individual drivers if they did ever happen, and
>>>>> certainly shouldn't apply to this bit of the infrastructure at any rate.
>>>>
>>>> I certainly need to update the pgsize_bitmap at runtime because I don't
>>>> know the supported page sizes until I've both (a) probed the hardware
>>>> and (b) allocated page tables for a domain. We've already discussed
>>>> moving the pgsize_bitmap out of the ops, but moving it somewhere where
>>>> it remains const doesn't really help.
>>>
>>> We can safely cast the call to get_ops in the SMMU driver though, since
>>> we'll know that we put a mutable per-instance ops in there in the first
>>> place. At least that way drivers that aren't taking advantage and just pass
>>> their static const ops around shouldn't provoke warnings. I deliberately
>>> didn't touch anything beyond get_ops as that would be too disruptive.
>>>
>>>> Can I just take the patch that Grant acked, in the interest of getting
>>>> something merged? As you say, there's plenty of planned changes in this
>>>> area anyway. I plan to send Olof a pull request this afternoon.
>>>
>>> Grant, Thierry? Personally I'm not fussed either way - the sooner something
>>> goes in, the sooner I can carry on working at replacing it :D
>> I've already acked it. Why are we still talking about it? :-D
> Am I missing something? Why is there a need to rush things? Are there
> actually drivers that depend on this that will be merged during the 3.19
> merge window? It seems like that'd be cutting it really close given
> where we are in the release cycle.
>
> If that's not the case, why even bother getting this hack into 3.19 if
> nobody uses it and we're going to change it in 3.20 anyway?
There are Exynos SYSMMU patches ready & waiting for this gets merged...
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
next prev parent reply other threads:[~2014-12-05 13:49 UTC|newest]
Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-01 16:57 [PATCH v6 0/8] Introduce automatic DMA configuration for IOMMU masters Will Deacon
2014-12-01 16:57 ` [PATCH v6 1/8] iommu: provide early initialisation hook for IOMMU drivers Will Deacon
2014-12-01 23:54 ` Rob Herring
2014-12-02 9:23 ` Marek Szyprowski
2014-12-02 9:36 ` Arnd Bergmann
2014-12-02 9:43 ` Will Deacon
2014-12-02 12:05 ` Thierry Reding
2014-12-02 10:30 ` Pantelis Antoniou
2014-12-02 14:16 ` Grant Likely
2014-12-03 19:57 ` Arnd Bergmann
2014-12-04 9:49 ` Will Deacon
2014-12-04 10:10 ` Arnd Bergmann
2014-12-04 10:21 ` Will Deacon
2014-12-04 11:19 ` Arnd Bergmann
2014-12-04 11:25 ` Grant Likely
2014-12-04 11:52 ` Will Deacon
2014-12-04 12:43 ` Grant Likely
2014-12-04 12:26 ` Robin Murphy
2014-12-04 12:42 ` Grant Likely
2014-12-04 13:43 ` Robin Murphy
2014-12-04 13:58 ` Grant Likely
2014-12-04 14:49 ` Thierry Reding
2014-12-04 17:42 ` Robin Murphy
2014-12-04 17:58 ` Grant Likely
2014-12-04 19:42 ` Robin Murphy
2014-12-05 12:10 ` Will Deacon
2014-12-05 12:21 ` Arnd Bergmann
2014-12-05 12:35 ` Robin Murphy
2014-12-05 13:06 ` Grant Likely
2014-12-05 13:18 ` Thierry Reding
2014-12-05 13:21 ` Grant Likely
2014-12-05 13:31 ` Thierry Reding
2014-12-05 13:49 ` Marek Szyprowski [this message]
2014-12-04 12:51 ` Arnd Bergmann
2014-12-01 16:57 ` [PATCH v6 2/8] dma-mapping: replace set_arch_dma_coherent_ops with arch_setup_dma_ops Will Deacon
2014-12-01 22:58 ` Rob Herring
2014-12-02 9:16 ` Arnd Bergmann
2014-12-01 16:57 ` [PATCH v6 3/8] iommu: add new iommu_ops callback for adding an OF device Will Deacon
2014-12-01 16:57 ` [PATCH v6 4/8] iommu: provide helper function to configure an IOMMU for an of master Will Deacon
2014-12-01 16:57 ` [PATCH v6 5/8] iommu: fix initialization without 'add_device' callback Will Deacon
2014-12-01 16:57 ` [PATCH v6 6/8] dma-mapping: detect and configure IOMMU in of_dma_configure Will Deacon
2014-12-01 23:06 ` Rob Herring
2014-12-10 14:52 ` Rob Clark
2014-12-10 15:08 ` Will Deacon
2014-12-10 15:54 ` Robin Murphy
2014-12-10 15:56 ` Laurent Pinchart
2014-12-14 15:49 ` Laurent Pinchart
2014-12-14 15:59 ` Laurent Pinchart
2014-12-15 17:10 ` Will Deacon
2014-12-15 16:40 ` Will Deacon
2014-12-15 17:16 ` Laurent Pinchart
2014-12-15 18:09 ` Will Deacon
2014-12-16 12:08 ` Arnd Bergmann
2014-12-17 12:09 ` Will Deacon
2014-12-17 14:15 ` Arnd Bergmann
2014-12-17 14:45 ` Will Deacon
2014-12-17 15:35 ` Arnd Bergmann
2014-12-17 17:17 ` Will Deacon
2014-12-17 19:48 ` Arnd Bergmann
2014-12-21 10:04 ` Will Deacon
2014-12-22 13:36 ` Arnd Bergmann
2015-01-07 18:57 ` Will Deacon
2015-01-07 19:29 ` Arnd Bergmann
2015-01-08 10:53 ` Will Deacon
2014-12-17 14:27 ` Robin Murphy
2014-12-17 15:01 ` Will Deacon
2014-12-17 15:38 ` Arnd Bergmann
2014-12-17 17:20 ` Will Deacon
2014-12-17 0:05 ` Laurent Pinchart
2014-12-14 15:51 ` Laurent Pinchart
2014-12-15 11:32 ` Will Deacon
2014-12-17 0:19 ` Laurent Pinchart
2014-12-17 11:14 ` Will Deacon
2014-12-01 16:57 ` [PATCH v6 7/8] arm: call iommu_init before of_platform_populate Will Deacon
2014-12-01 16:57 ` [PATCH v6 8/8] arm: dma-mapping: plumb our iommu mapping ops into arch_setup_dma_ops Will Deacon
2015-01-14 9:00 ` Alexandre Courbot
2015-01-14 10:46 ` Will Deacon
2015-01-14 13:51 ` Heiko Stübner
2015-01-14 19:17 ` Will Deacon
2015-01-15 8:30 ` Thierry Reding
2015-01-15 11:13 ` Will Deacon
2015-01-15 2:57 ` Alexandre Courbot
2015-01-15 8:28 ` Thierry Reding
2015-01-15 11:12 ` Will Deacon
2015-01-15 23:18 ` Laurent Pinchart
2015-01-18 6:54 ` Alexandre Courbot
2015-01-18 11:18 ` Laurent Pinchart
2015-01-19 11:12 ` Will Deacon
2015-01-19 11:34 ` Laurent Pinchart
2015-01-19 12:31 ` Thierry Reding
2015-01-20 15:14 ` Laurent Pinchart
2015-01-20 15:19 ` Will Deacon
2015-01-20 15:21 ` Will Deacon
2015-01-20 15:35 ` Laurent Pinchart
2015-01-19 12:43 ` Thierry Reding
2015-01-19 12:50 ` Will Deacon
2015-01-19 13:36 ` Thierry Reding
2015-01-20 13:50 ` Laurent Pinchart
2015-01-19 16:13 ` Arnd Bergmann
2015-01-20 16:41 ` Laurent Pinchart
2015-01-19 12:36 ` Thierry Reding
2015-01-19 15:52 ` Arnd Bergmann
2015-01-19 16:21 ` Thierry Reding
2015-01-19 17:02 ` Arnd Bergmann
2015-01-20 13:47 ` Laurent Pinchart
2015-01-19 12:49 ` Thierry Reding
2015-01-20 14:05 ` Laurent Pinchart
2014-12-05 7:12 ` [PATCH v6 0/8] Introduce automatic DMA configuration for IOMMU masters Olof Johansson
2014-12-05 12:11 ` Will Deacon
2014-12-15 0:24 ` [PATCH/RFC] iommu/ipmmu-vmsa: Use DT-based instantiation Laurent Pinchart
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