From: Hiroshi Doyu <hdoyu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
To: Marek Szyprowski
<m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
Cc: "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"linaro-mm-sig-cunTk1MwBs8s++Sfvej+rw@public.gmane.org"
<linaro-mm-sig-cunTk1MwBs8s++Sfvej+rw@public.gmane.org>,
"iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org"
<iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>,
"linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@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: Mon, 24 Jun 2013 08:17:59 +0300 [thread overview]
Message-ID: <20130624081759.76e66d42bbf7c2c54ed1975c@nvidia.com> (raw)
In-Reply-To: <20130621160344.GM11309-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
On Fri, 21 Jun 2013 18:03:44 +0200
Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org> wrote:
> 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.
Ok, thanks. One more question, IOMMU H/W sometimes supports more
platform specific attributes than READ/WRITE. For example, in OMAP,
#define IOMMU_FLAG (IOVMF_ENDIAN_LITTLE | IOVMF_ELSZ_8)
Is there any way to deal with those platform specific attrs from DMA
mapping API POV?
next prev parent reply other threads:[~2013-06-24 5:17 UTC|newest]
Thread overview: 23+ 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
[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
[not found] ` <CAMcxFTRnnCnPnvMi89r7rUsN4xeYzZGqy9s5v5ukm_fJ_d_RGg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
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
[not found] ` <CAMcxFTS0dUUEfGj-=-cb_rdfy+qWvtsaoR6Tv+-x05XX0mZmmw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
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
[not found] ` <201306201213.13644.arnd-r2nGTMty4D4@public.gmane.org>
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
[not found] ` <201306201257.58419.arnd-r2nGTMty4D4@public.gmane.org>
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
[not found] ` <CAH9JG2VUCJErBNwT0_u_9niaSWUza5gJ-+q8OOJhrrdw5D-hUg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
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
[not found] ` <20130620093152.GE2842-MRww78TxoiP5vMa5CHWGZ34zcgK1vI+I0E9HWUfgJXw@public.gmane.org>
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
[not found] ` <20130620101110.GB18536-5wv7dgnIgG8@public.gmane.org>
2013-06-20 11:00 ` Hiroshi Doyu
2013-06-20 10:12 ` Will Deacon
2013-06-21 7:17 ` Marek Szyprowski
[not found] ` <51C3FE27.5070702-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2013-06-21 16:03 ` Joerg Roedel
[not found] ` <20130621160344.GM11309-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2013-06-24 5:17 ` Hiroshi Doyu [this message]
[not found] ` <20130624081759.76e66d42bbf7c2c54ed1975c-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
2013-06-24 7:21 ` Joerg Roedel
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