From: Christoph Hellwig <hch@lst.de>
To: Marek Szyprowski <m.szyprowski@samsung.com>
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>,
Ajay kumar <ajaynumb@gmail.com>,
Shaik Ameer Basha <shaik.ameer@samsung.com>,
Robin Murphy <robin.murphy@arm.com>,
hch@lst.de
Subject: Re: IOVA allocation dependency between firmware buffer and remaining buffers
Date: Wed, 23 Sep 2020 08:58:08 +0200 [thread overview]
Message-ID: <20200923065808.GA16366@lst.de> (raw)
In-Reply-To: <11584d09-5995-6133-3bd3-8f7a0afd0e01@samsung.com>
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.
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Shaik Ameer Basha <shaik.samsung@gmail.com>,
Robin Murphy <robin.murphy@arm.com>,
Ajay kumar <ajaynumb@gmail.com>,
Linux IOMMU <iommu@lists.linux-foundation.org>,
linux-mm@kvack.org, Joerg Roedel <joro@8bytes.org>,
Rob Clark <robdclark@gmail.com>,
Thierry Reding <thierry.reding@gmail.com>,
jean-philippe@linaro.org, will@kernel.org, hch@lst.de,
baolu.lu@linux.intel.com,
Shaik Ameer Basha <shaik.ameer@samsung.com>
Subject: Re: IOVA allocation dependency between firmware buffer and remaining buffers
Date: Wed, 23 Sep 2020 08:58:08 +0200 [thread overview]
Message-ID: <20200923065808.GA16366@lst.de> (raw)
In-Reply-To: <11584d09-5995-6133-3bd3-8f7a0afd0e01@samsung.com>
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.
next prev parent reply other threads:[~2020-09-23 6:58 UTC|newest]
Thread overview: 38+ 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
2020-04-20 15:54 ` Ajay kumar
2020-04-24 15:04 ` Ajay kumar
2020-04-24 15:04 ` Ajay kumar
2020-04-24 15:29 ` Robin Murphy
2020-04-24 15:29 ` Robin Murphy
2020-04-24 16:15 ` Shaik Ameer Basha
2020-04-24 16:15 ` Shaik Ameer Basha
2020-09-23 6:48 ` Marek Szyprowski
2020-09-23 6:48 ` Marek Szyprowski
2020-09-23 6:58 ` Christoph Hellwig [this message]
2020-09-23 6:58 ` Christoph Hellwig
2020-09-23 7:45 ` Ajay kumar
2020-09-23 7:45 ` Ajay kumar
2020-09-23 13:47 ` Christoph Hellwig
2020-09-23 13:47 ` Christoph Hellwig
2020-09-23 8:25 ` Ajay Kumar
2020-09-23 8:25 ` Ajay Kumar
2020-09-24 8:28 ` Joerg Roedel
2020-09-24 8:28 ` Joerg Roedel
2020-09-24 8:46 ` Marek Szyprowski
2020-09-24 8:46 ` Marek Szyprowski
2020-09-24 10:16 ` Thierry Reding
2020-09-24 10:16 ` Thierry Reding
2020-09-24 10:40 ` Robin Murphy
2020-09-24 10:40 ` Robin Murphy
2020-09-24 10:47 ` Marek Szyprowski
2020-09-24 10:47 ` Marek Szyprowski
2020-09-24 11:06 ` Robin Murphy
2020-09-24 11:06 ` Robin Murphy
2020-09-24 14:14 ` Shaik Ameer Basha
2020-09-24 14:14 ` Shaik Ameer Basha
2020-09-28 6:52 ` Marek Szyprowski
2020-09-28 6:52 ` Marek Szyprowski
2020-09-24 10:41 ` Marek Szyprowski
2020-09-24 10:41 ` Marek Szyprowski
2020-09-24 14:33 ` Thierry Reding
2020-09-24 14:33 ` Thierry Reding
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