From: Ajay kumar <ajaynumb@gmail.com>
To: Christoph Hellwig <hch@lst.de>
Cc: jean-philippe@linaro.org, will@kernel.org, linux-mm@kvack.org,
Linux IOMMU <iommu@lists.linux-foundation.org>,
Thierry Reding <thierry.reding@gmail.com>,
Shaik Ameer Basha <shaik.ameer@samsung.com>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: IOVA allocation dependency between firmware buffer and remaining buffers
Date: Wed, 23 Sep 2020 13:15:33 +0530 [thread overview]
Message-ID: <CAEC9eQMoqYBU_9H9QoAwwayR8u2MK4aMDvTocOqrPRK3cuVeHw@mail.gmail.com> (raw)
In-Reply-To: <20200923065808.GA16366@lst.de>
Hello all,
We pretty much tried to solve the same issue here with a new API in DMA-IOMMU:
https://lore.kernel.org/linux-iommu/20200811054912.GA301@infradead.org/T/
Christopher- the user part would be MFC devices on exynos platforms
Thanks,
Ajay
On 9/23/20, Christoph Hellwig <hch@lst.de> wrote:
> On Wed, Sep 23, 2020 at 08:48:26AM +0200, Marek Szyprowski wrote:
>> Hi Shaik,
>>
>> I've run into similar problem while adapting S5P-MFC and Exynos4-IS
>> drivers for generic IOMMU-DMA framework. Here is my first solution:
>> https://lore.kernel.org/linux-samsung-soc/20200918144833.14618-1-m.szyprowski@samsung.com/T/
>>
>>
>>
>> It allows to remap given buffer at the specific IOVA address, although
>> it doesn't guarantee that those specific addresses won't be later used
>> by the IOVA allocator. Probably it would make sense to add an API for
>> generic IOMMU-DMA framework to mark the given IOVA range as
>> reserved/unused to protect them.
>
> If you want to use IOVA addresses in a device otherwise managed by
> dma-iommu we need to expose an API through the dma API. Can you please
> include the iommu list in the discussion of your series?
>
> I don't think using the raw IOMMU API is a very idea in these drivers,
> we probably want a way to change the allocator algorithm or hint the
> next IOVA and keep using the normal DMA API. Maybe Robin has a better
> idea.
>
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next prev parent reply other threads:[~2020-09-23 8:37 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-20 15:54 IOVA allocation dependency between firmware buffer and remaining buffers Ajay kumar
2020-04-24 15:04 ` Ajay kumar
2020-04-24 15:29 ` Robin Murphy
2020-04-24 16:15 ` Shaik Ameer Basha
2020-09-23 6:48 ` Marek Szyprowski
2020-09-23 6:58 ` Christoph Hellwig
2020-09-23 7:45 ` Ajay kumar [this message]
2020-09-23 13:47 ` Christoph Hellwig
2020-09-23 8:25 ` Ajay Kumar
2020-09-24 8:28 ` Joerg Roedel
2020-09-24 8:46 ` Marek Szyprowski
2020-09-24 10:16 ` Thierry Reding
2020-09-24 10:40 ` Robin Murphy
2020-09-24 10:47 ` Marek Szyprowski
2020-09-24 11:06 ` Robin Murphy
2020-09-24 14:14 ` Shaik Ameer Basha
2020-09-28 6:52 ` Marek Szyprowski
2020-09-24 10:41 ` Marek Szyprowski
2020-09-24 14:33 ` Thierry Reding
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