From: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
To: Marek Szyprowski <m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
Cc: linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linaro-mm-sig-cunTk1MwBs8s++Sfvej+rw@public.gmane.org,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [RFC 0/3] How to pass IOMMU map attr via DMA API?
Date: Fri, 21 Jun 2013 18:03:44 +0200 [thread overview]
Message-ID: <20130621160344.GM11309@8bytes.org> (raw)
In-Reply-To: <51C3FE27.5070702-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
On Fri, Jun 21, 2013 at 09:17:59AM +0200, Marek Szyprowski wrote:
> Using DMA attributes for this seems to be a bad idea. The dma direction
> parameter is much more appropriate. Will Deacon recently posted a patch
> which does it right, see:
>
> https://git.linaro.org/gitweb?p=people/mszyprowski/linux-dma-mapping.git;a=commit;h=8fc3749bd31d139db58f874e093255fe62505968
Agreed, that is one usecase the dma-direction parameter was made for. In
particular:
DMA_FROM_DEVICE -> Write only mapping
DMA_TO_DEVICE -> Read only mapping
DMA_BIDIRECTIONAL -> Read/Write mapping
So no need to use the dma attributes for that.
Joerg
WARNING: multiple messages have this Message-ID (diff)
From: joro@8bytes.org (Joerg Roedel)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC 0/3] How to pass IOMMU map attr via DMA API?
Date: Fri, 21 Jun 2013 18:03:44 +0200 [thread overview]
Message-ID: <20130621160344.GM11309@8bytes.org> (raw)
In-Reply-To: <51C3FE27.5070702@samsung.com>
On Fri, Jun 21, 2013 at 09:17:59AM +0200, Marek Szyprowski wrote:
> Using DMA attributes for this seems to be a bad idea. The dma direction
> parameter is much more appropriate. Will Deacon recently posted a patch
> which does it right, see:
>
> https://git.linaro.org/gitweb?p=people/mszyprowski/linux-dma-mapping.git;a=commit;h=8fc3749bd31d139db58f874e093255fe62505968
Agreed, that is one usecase the dma-direction parameter was made for. In
particular:
DMA_FROM_DEVICE -> Write only mapping
DMA_TO_DEVICE -> Read only mapping
DMA_BIDIRECTIONAL -> Read/Write mapping
So no need to use the dma attributes for that.
Joerg
next prev parent reply other threads:[~2013-06-21 16:03 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-20 5:49 [RFC 0/3] How to pass IOMMU map attr via DMA API? Hiroshi Doyu
2013-06-20 5:49 ` Hiroshi Doyu
[not found] ` <1371707384-30037-1-git-send-email-hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2013-06-20 5:49 ` [RFC 1/3] common: DMA-mapping: add DMA_ATTR_READ_ONLY attribute Hiroshi Doyu
2013-06-20 5:49 ` [RFC 2/3] ARM: dma-mapping: Pass DMA attrs as IOMMU prot Hiroshi Doyu
[not found] ` <1371707384-30037-3-git-send-email-hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2013-06-20 8:07 ` [Linaro-mm-sig] " Nishanth Peethambaran
2013-06-20 8:07 ` Nishanth Peethambaran
[not found] ` <CAMcxFTRnnCnPnvMi89r7rUsN4xeYzZGqy9s5v5ukm_fJ_d_RGg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-06-20 8:24 ` Hiroshi Doyu
2013-06-20 8:24 ` Hiroshi Doyu
[not found] ` <20130620.112439.1330557591655135630.hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2013-06-20 8:55 ` Nishanth Peethambaran
2013-06-20 8:55 ` Nishanth Peethambaran
[not found] ` <CAMcxFTS0dUUEfGj-=-cb_rdfy+qWvtsaoR6Tv+-x05XX0mZmmw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-06-20 9:54 ` Hiroshi Doyu
2013-06-20 9:54 ` Hiroshi Doyu
[not found] ` <20130620.125431.1161068035083905855.hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2013-06-20 10:13 ` Arnd Bergmann
2013-06-20 10:13 ` Arnd Bergmann
[not found] ` <201306201213.13644.arnd-r2nGTMty4D4@public.gmane.org>
2013-06-20 10:34 ` Hiroshi Doyu
2013-06-20 10:34 ` Hiroshi Doyu
[not found] ` <20130620.133407.798194318297047071.hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2013-06-20 10:57 ` Arnd Bergmann
2013-06-20 10:57 ` Arnd Bergmann
[not found] ` <201306201257.58419.arnd-r2nGTMty4D4@public.gmane.org>
2013-06-20 12:49 ` Nishanth Peethambaran
2013-06-20 12:49 ` Nishanth Peethambaran
2013-06-20 5:49 ` [RFC 3/3] iommu/tegra: smmu: Support read-only mapping Hiroshi Doyu
[not found] ` <1371707384-30037-4-git-send-email-hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2013-06-20 6:50 ` [Linaro-mm-sig] " Kyungmin Park
2013-06-20 6:50 ` Kyungmin Park
[not found] ` <CAH9JG2VUCJErBNwT0_u_9niaSWUza5gJ-+q8OOJhrrdw5D-hUg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-06-20 7:27 ` Hiroshi Doyu
2013-06-20 7:27 ` Hiroshi Doyu
2013-06-20 9:31 ` [RFC 0/3] How to pass IOMMU map attr via DMA API? Will Deacon
2013-06-20 9:31 ` Will Deacon
[not found] ` <20130620093152.GE2842-MRww78TxoiP5vMa5CHWGZ34zcgK1vI+I0E9HWUfgJXw@public.gmane.org>
2013-06-20 9:59 ` Hiroshi Doyu
2013-06-20 9:59 ` Hiroshi Doyu
[not found] ` <20130620.125929.2250094502232662356.hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2013-06-20 10:11 ` Catalin Marinas
2013-06-20 10:11 ` Catalin Marinas
[not found] ` <20130620101110.GB18536-5wv7dgnIgG8@public.gmane.org>
2013-06-20 11:00 ` Hiroshi Doyu
2013-06-20 11:00 ` Hiroshi Doyu
2013-06-20 10:12 ` Will Deacon
2013-06-20 10:12 ` Will Deacon
2013-06-21 7:17 ` Marek Szyprowski
2013-06-21 7:17 ` Marek Szyprowski
[not found] ` <51C3FE27.5070702-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2013-06-21 16:03 ` Joerg Roedel [this message]
2013-06-21 16:03 ` Joerg Roedel
[not found] ` <20130621160344.GM11309-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2013-06-24 5:17 ` Hiroshi Doyu
2013-06-24 5:17 ` Hiroshi Doyu
[not found] ` <20130624081759.76e66d42bbf7c2c54ed1975c-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2013-06-24 7:21 ` Joerg Roedel
2013-06-24 7:21 ` Joerg Roedel
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=20130621160344.GM11309@8bytes.org \
--to=joro-zlv9swrftaidnm+yrofe0a@public.gmane.org \
--cc=iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org \
--cc=linaro-mm-sig-cunTk1MwBs8s++Sfvej+rw@public.gmane.org \
--cc=linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org \
--cc=linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.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.