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From: Eric Boxer <boxerspam1-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Linux Samsung SOC
	<linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Hyunwoong Kim
	<khw0178.kim-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	Bartlomiej Zolnierkiewicz
	<b.zolnierkie-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	Sachin Kamat
	<sachin.kamat-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Prathyush <prathyush.k-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	Subash Patel
	<supash.ramaswamy-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Linux Kernel
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Keyyoung Park
	<keyyoung.park-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	Rahul Sharma
	<rahul.sharma-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	Grant Grundler <grundler-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Linux IOMMU
	<iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>,
	Kukjin Kim <kgene.kim-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	Antonios Motakis
	<a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org>,
	Cho KyongHo <pullip.cho-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	kvmarm <kvmarm-FPEHb7Xf0XXUo1n7N8X6UoWGPAHP3yOg@public.gmane.org>,
	Linux ARM Kernel
	<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>
Subject: Re: [PATCH v8 06/12] ARM: dts: Add description of System MMU of Exynos SoCs
Date: Tue, 6 Aug 2013 11:21:08 -0500	[thread overview]
Message-ID: <3BCA86D7-5A34-418E-A468-F7DF62FD1592@gmail.com> (raw)
In-Reply-To: <CANEJEGtQuKG5err-R7SxD6m+aJWVmn47X9NJLx7UzaRkKhUMoQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>


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Ok  

---Sent from Boxer | http://getboxer.com

Hi Marek,



On Tue, Aug 6, 2013 at 6:17 AM, Marek Szyprowski

<m.szyprowski@samsung.com> wrote:

...

> IMHO it is much better to have a simple driver, which binds to a single

> IOMMU controller and leave it to the driver whether to have a same virtual address

> space for all parts of FIMC-IS or MFC submodules/memory ports or not.



I understand this part. I having written the IOMMU support for 4

different IOMMUs, all of which had exactly one IO Page Table and one

IOMMU shared by many devices.



> Just make sure that it will be possible to attach more than one sysmmu

> controller to one iommu domain.



I don't understand how this is possible. Can someone explain this

better in the IOMMU documentation please?



"iommu domain" to me means one virtual IO address space for attached

devices that can master DMA transactions. The IOMMU then uses it's IO

Page Table to translate the DMA address to the system physical address

space and forwards the transaction.



What is the role of the sysmmu in all of this?

Is the sysmmu just the MMU (or collection of MMU) for host DRAM?

Or is sysmmu responsible for "other stuff"? (clocks, power domains, MMU, etc)



I can understand we might have multiple MMUs in a system...e.g. every

range of memory might have it's own MMU. But they share the same

physical address space and generally live under one page table.

Because of "one page table" I would consider them one entity from the

the IOMMUs perspective.



thanks,

grant

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  parent reply	other threads:[~2013-08-06 16:21 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-26 11:28 [PATCH v8 06/12] ARM: dts: Add description of System MMU of Exynos SoCs Cho KyongHo
2013-07-26 17:58 ` Grant Grundler
     [not found]   ` <CANEJEGsHyDP+AZejV57gMKPnbi0bi4yiWc42gPM9YuZzOewwLw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-07-27  9:29     ` Cho KyongHo
2013-07-27 13:54 ` Rob Herring
     [not found]   ` <CAL_JsqJdh5F0rK3koAW7DvRVU3RwS5pLgR5sV_Bak+K-6CrRFA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-08-01 13:05     ` Cho KyongHo
2013-08-08 13:09       ` Rob Herring
     [not found]         ` <CAL_Jsq+_5GekzXpjWrtKZi2jWuxHSJxkPmVC4zmakfjAYai=eA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-08-08 21:38           ` Tomasz Figa
2013-08-08 21:43             ` Will Deacon
     [not found]               ` <20130808214343.GA19383-MRww78TxoiP5vMa5CHWGZ34zcgK1vI+I0E9HWUfgJXw@public.gmane.org>
2013-08-09  2:24                 ` Cho KyongHo
2013-07-29  6:37 ` Sachin Kamat
2013-07-29  7:20   ` Cho KyongHo
2013-07-29  7:57   ` Cho KyongHo
2013-07-29  8:05     ` Sachin Kamat
     [not found]       ` <CAK9yfHyeOQZzf_3Nv-fmuYdZtL8dzZequdx2ZddnUyXDn66bOg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-08-01 13:12         ` Cho KyongHo
2013-08-02 17:14 ` Bartlomiej Zolnierkiewicz
2013-08-05 11:16   ` Cho KyongHo
2013-08-05 13:09     ` Bartlomiej Zolnierkiewicz
2013-08-05 13:34       ` Marek Szyprowski
2013-08-06  9:54       ` Cho KyongHo
2013-08-06 13:17         ` Marek Szyprowski
2013-08-06 16:07           ` Grant Grundler
     [not found]             ` <CANEJEGtQuKG5err-R7SxD6m+aJWVmn47X9NJLx7UzaRkKhUMoQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-08-06 16:21               ` Eric Boxer [this message]
2013-08-07 12:07             ` Cho KyongHo
2013-08-07 16:21               ` Grant Grundler
2013-08-08  2:19                 ` Cho KyongHo
2013-10-07 13:44 ` Rob Herring
2013-10-08  4:38   ` Cho KyongHo

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