From: Christoph Hellwig <hch@infradead.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Sven Peter <sven@svenpeter.dev>, Will Deacon <will@kernel.org>,
Joerg Roedel <joro@8bytes.org>, Arnd Bergmann <arnd@kernel.org>,
devicetree@vger.kernel.org, Hector Martin <marcan@marcan.st>,
linux-kernel@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
Mohamed Mediouni <mohamed.mediouni@caramail.com>,
Stan Skowronek <stan@corellium.com>,
linux-arm-kernel@lists.infradead.org,
Mark Kettenis <mark.kettenis@xs4all.nl>,
iommu@lists.linux-foundation.org,
Alexander Graf <graf@amazon.com>,
Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>,
Rob Herring <robh+dt@kernel.org>,
r.czerwinski@pengutronix.de,
Mauro Carvalho Chehab <mchehab@kernel.org>,
linux-media@vger.kernel.org
Subject: Re: [PATCH v4 0/3] Apple M1 DART IOMMU driver
Date: Fri, 16 Jul 2021 07:24:03 +0100 [thread overview]
Message-ID: <YPEmA0rdXHiGtHSx@infradead.org> (raw)
In-Reply-To: <7261df01-34a9-4e53-37cd-ae1aa15b1fb4@arm.com>
On Wed, Jul 14, 2021 at 07:19:50PM +0100, Robin Murphy wrote:
> Even at the DMA API level you could hide *some* of it (at the cost of
> effectively only having 1/4 of the usable address space), but there are
> still cases like where v4l2 has a hard requirement that a page-aligned
> scatterlist can be mapped into a contiguous region of DMA addresses.
Where does v4l2 make that broken assumption? Plenty of dma mapping
implementations including dma-direct do not support that.
Drivers need to call dma_get_merge_boundary() to check for that kind of
behavior.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Arnd Bergmann <arnd@kernel.org>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
r.czerwinski@pengutronix.de, linux-media@vger.kernel.org,
devicetree@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
Hector Martin <marcan@marcan.st>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
Rob Herring <robh+dt@kernel.org>,
Alexander Graf <graf@amazon.com>,
Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>,
Mohamed Mediouni <mohamed.mediouni@caramail.com>,
Mark Kettenis <mark.kettenis@xs4all.nl>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org,
Stan Skowronek <stan@corellium.com>
Subject: Re: [PATCH v4 0/3] Apple M1 DART IOMMU driver
Date: Fri, 16 Jul 2021 07:24:03 +0100 [thread overview]
Message-ID: <YPEmA0rdXHiGtHSx@infradead.org> (raw)
In-Reply-To: <7261df01-34a9-4e53-37cd-ae1aa15b1fb4@arm.com>
On Wed, Jul 14, 2021 at 07:19:50PM +0100, Robin Murphy wrote:
> Even at the DMA API level you could hide *some* of it (at the cost of
> effectively only having 1/4 of the usable address space), but there are
> still cases like where v4l2 has a hard requirement that a page-aligned
> scatterlist can be mapped into a contiguous region of DMA addresses.
Where does v4l2 make that broken assumption? Plenty of dma mapping
implementations including dma-direct do not support that.
Drivers need to call dma_get_merge_boundary() to check for that kind of
behavior.
_______________________________________________
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@infradead.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Sven Peter <sven@svenpeter.dev>, Will Deacon <will@kernel.org>,
Joerg Roedel <joro@8bytes.org>, Arnd Bergmann <arnd@kernel.org>,
devicetree@vger.kernel.org, Hector Martin <marcan@marcan.st>,
linux-kernel@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
Mohamed Mediouni <mohamed.mediouni@caramail.com>,
Stan Skowronek <stan@corellium.com>,
linux-arm-kernel@lists.infradead.org,
Mark Kettenis <mark.kettenis@xs4all.nl>,
iommu@lists.linux-foundation.org,
Alexander Graf <graf@amazon.com>,
Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>,
Rob Herring <robh+dt@kernel.org>,
r.czerwinski@pengutronix.de,
Mauro Carvalho Chehab <mchehab@kernel.org>,
linux-media@vger.kernel.org
Subject: Re: [PATCH v4 0/3] Apple M1 DART IOMMU driver
Date: Fri, 16 Jul 2021 07:24:03 +0100 [thread overview]
Message-ID: <YPEmA0rdXHiGtHSx@infradead.org> (raw)
In-Reply-To: <7261df01-34a9-4e53-37cd-ae1aa15b1fb4@arm.com>
On Wed, Jul 14, 2021 at 07:19:50PM +0100, Robin Murphy wrote:
> Even at the DMA API level you could hide *some* of it (at the cost of
> effectively only having 1/4 of the usable address space), but there are
> still cases like where v4l2 has a hard requirement that a page-aligned
> scatterlist can be mapped into a contiguous region of DMA addresses.
Where does v4l2 make that broken assumption? Plenty of dma mapping
implementations including dma-direct do not support that.
Drivers need to call dma_get_merge_boundary() to check for that kind of
behavior.
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-07-16 6:25 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-27 14:34 [PATCH v4 0/3] Apple M1 DART IOMMU driver Sven Peter
2021-06-27 14:34 ` Sven Peter
2021-06-27 14:34 ` Sven Peter via iommu
2021-06-27 14:34 ` [PATCH v4 1/3] iommu: io-pgtable: add DART pagetable format Sven Peter
2021-06-27 14:34 ` Sven Peter
2021-06-27 14:34 ` Sven Peter via iommu
2021-06-28 10:54 ` Alexander Graf
2021-06-28 10:54 ` Alexander Graf
2021-06-28 10:54 ` Alexander Graf via iommu
2021-06-29 7:37 ` Sven Peter
2021-06-29 7:37 ` Sven Peter
2021-06-29 7:37 ` Sven Peter via iommu
2021-06-29 12:04 ` Alexander Graf
2021-06-29 12:04 ` Alexander Graf
2021-06-29 12:04 ` Alexander Graf via iommu
2021-06-30 13:53 ` Alyssa Rosenzweig
2021-06-30 13:53 ` Alyssa Rosenzweig
2021-06-30 13:53 ` Alyssa Rosenzweig
2021-07-13 19:17 ` Robin Murphy
2021-07-13 19:17 ` Robin Murphy
2021-07-13 19:17 ` Robin Murphy
2021-07-14 17:39 ` Sven Peter
2021-07-14 17:39 ` Sven Peter
2021-07-14 17:39 ` Sven Peter via iommu
2021-06-27 14:34 ` [PATCH v4 2/3] dt-bindings: iommu: add DART iommu bindings Sven Peter
2021-06-27 14:34 ` Sven Peter
2021-06-27 14:34 ` Sven Peter via iommu
2021-06-30 13:54 ` Alyssa Rosenzweig
2021-06-30 13:54 ` Alyssa Rosenzweig
2021-06-30 13:54 ` Alyssa Rosenzweig
2021-06-27 14:34 ` [PATCH v4 3/3] iommu: dart: Add DART iommu driver Sven Peter
2021-06-27 14:34 ` Sven Peter
2021-06-27 14:34 ` Sven Peter via iommu
2021-06-30 13:49 ` Alyssa Rosenzweig
2021-06-30 13:49 ` Alyssa Rosenzweig
2021-06-30 13:49 ` Alyssa Rosenzweig
2021-07-12 11:02 ` Sven Peter
2021-07-12 11:02 ` Sven Peter
2021-07-12 11:02 ` Sven Peter via iommu
2021-07-12 13:53 ` Alyssa Rosenzweig
2021-07-12 13:53 ` Alyssa Rosenzweig
2021-07-12 13:53 ` Alyssa Rosenzweig
2021-07-13 23:23 ` Robin Murphy
2021-07-13 23:23 ` Robin Murphy
2021-07-13 23:23 ` Robin Murphy
2021-07-15 16:41 ` Sven Peter
2021-07-15 16:41 ` Sven Peter
2021-07-15 16:41 ` Sven Peter via iommu
2021-07-19 18:15 ` Robin Murphy
2021-07-19 18:15 ` Robin Murphy
2021-07-19 18:15 ` Robin Murphy
2021-07-25 12:40 ` Sven Peter
2021-07-25 12:40 ` Sven Peter
2021-07-25 12:40 ` Sven Peter via iommu
2021-07-26 13:19 ` Alyssa Rosenzweig
2021-07-26 13:19 ` Alyssa Rosenzweig
2021-07-26 13:19 ` Alyssa Rosenzweig
2021-07-14 18:19 ` [PATCH v4 0/3] Apple M1 DART IOMMU driver Robin Murphy
2021-07-14 18:19 ` Robin Murphy
2021-07-14 18:19 ` Robin Murphy
2021-07-14 20:51 ` Arnd Bergmann
2021-07-14 20:51 ` Arnd Bergmann
2021-07-14 20:51 ` Arnd Bergmann
2021-07-15 6:52 ` Joerg Roedel
2021-07-15 6:52 ` Joerg Roedel
2021-07-15 6:52 ` Joerg Roedel
2021-07-16 6:24 ` Christoph Hellwig [this message]
2021-07-16 6:24 ` Christoph Hellwig
2021-07-16 6:24 ` Christoph Hellwig
2021-07-16 15:32 ` Robin Murphy
2021-07-16 15:32 ` Robin Murphy
2021-07-16 15:32 ` Robin Murphy
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YPEmA0rdXHiGtHSx@infradead.org \
--to=hch@infradead.org \
--cc=alyssa.rosenzweig@collabora.com \
--cc=arnd@kernel.org \
--cc=devicetree@vger.kernel.org \
--cc=graf@amazon.com \
--cc=iommu@lists.linux-foundation.org \
--cc=joro@8bytes.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=marcan@marcan.st \
--cc=mark.kettenis@xs4all.nl \
--cc=maz@kernel.org \
--cc=mchehab@kernel.org \
--cc=mohamed.mediouni@caramail.com \
--cc=r.czerwinski@pengutronix.de \
--cc=robh+dt@kernel.org \
--cc=robin.murphy@arm.com \
--cc=stan@corellium.com \
--cc=sven@svenpeter.dev \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.