From: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
To: Laurent Pinchart
<laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
sakari.ailus-X3B1VOXEql0@public.gmane.org,
linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Florian Vaussard <florian.vaussard-p8DiymsW2f8@public.gmane.org>
Subject: Re: [PATCH 0/5] OMAP IOMMU fixes and IOMMU architecture questions
Date: Fri, 4 Apr 2014 12:18:11 +0200 [thread overview]
Message-ID: <20140404101811.GR13491@8bytes.org> (raw)
In-Reply-To: <1523736.5PrLY3OqT5@avalon>
On Fri, Mar 14, 2014 at 12:00:16PM +0100, Laurent Pinchart wrote:
> Right, we indeed need two levels of API, one for drivers such as remoteproc
> that need direct control of the IOMMU, and one for drivers that only need to
> map buffers without any additional requirement. In the second case the drivers
> should ideally use the DMA mapping API not even be aware that an IOMMU is
> present. This would require moving the ARM mapping allocation out of the
> client driver.
These two levels exist in the form of the DMA-API and the IOMMU-API. In
fact, the IOMMU-API was created to provide a way to drivers to specifiy
the IOVA->PHYS mappings on its own.
> The IOMMU core or the IOMMU driver will need to know whether the driver
> expects to control the IOMMU directly or to have it managed transparently. As
> this is a software configuration I don't think the information belongs to DT.
> The question is, how should this information be conveyed ?
The way this works on x86 is that a device driver can use the DMA-API
per default. If it wants to use the IOMMU-API it has to allocate a
domain and add the device it handles to this domain (it can't use
DMA-API anymore then).
Joerg
next prev parent reply other threads:[~2014-04-04 10:18 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-08 0:46 [PATCH 0/5] OMAP IOMMU fixes and IOMMU architecture questions Laurent Pinchart
2014-03-08 0:46 ` [PATCH 1/5] iommu/omap: Use the cache cleaning API Laurent Pinchart
[not found] ` <1394239574-2389-2-git-send-email-laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
2014-03-14 2:47 ` Suman Anna
2014-03-14 16:15 ` Santosh Shilimkar
2014-03-14 16:38 ` Laurent Pinchart
2014-03-14 17:51 ` Santosh Shilimkar
[not found] ` <5323418B.90805-l0cyMroinI0@public.gmane.org>
2014-03-15 1:49 ` Suman Anna
2014-03-15 17:54 ` Santosh Shilimkar
[not found] ` <532493DF.5010409-l0cyMroinI0@public.gmane.org>
2014-03-17 19:16 ` Suman Anna
2014-03-17 22:56 ` Laurent Pinchart
2014-03-14 16:57 ` Arnd Bergmann
2014-03-14 17:59 ` Santosh Shilimkar
[not found] ` <201403141757.48824.arnd-r2nGTMty4D4@public.gmane.org>
2014-03-17 23:12 ` Laurent Pinchart
2014-03-18 1:20 ` Suman Anna
[not found] ` <1394239574-2389-1-git-send-email-laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
2014-03-08 0:46 ` [PATCH 2/5] iommu/omap: Fix 'no page for' debug message in flush_iotlb_page() Laurent Pinchart
[not found] ` <1394239574-2389-3-git-send-email-laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
2014-03-13 22:16 ` Suman Anna
2014-03-14 9:50 ` Laurent Pinchart
2014-03-08 0:46 ` [PATCH 3/5] iommu/omap: Flush the TLB only after updating translation table entries Laurent Pinchart
[not found] ` <1394239574-2389-4-git-send-email-laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
2014-03-13 22:27 ` Suman Anna
[not found] ` <532230DA.30302-l0cyMroinI0@public.gmane.org>
2014-03-14 9:58 ` Laurent Pinchart
2014-03-15 0:18 ` Suman Anna
2014-03-14 2:33 ` [PATCH 0/5] OMAP IOMMU fixes and IOMMU architecture questions Suman Anna
2014-03-14 11:00 ` Laurent Pinchart
2014-03-16 21:54 ` Sakari Ailus
[not found] ` <20140316215455.GA2108-S+BSfZ9RZZmRSg0ZkenSGLdO1Tsj/99ntUK59QYPAWc@public.gmane.org>
2014-03-17 19:58 ` Suman Anna
2014-03-17 22:44 ` Laurent Pinchart
2014-04-04 12:23 ` Marek Szyprowski
[not found] ` <533EA45D.70002-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2014-04-08 13:09 ` Laurent Pinchart
2014-04-04 10:18 ` Joerg Roedel [this message]
[not found] ` <20140404101811.GR13491-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2014-04-08 12:50 ` Laurent Pinchart
2014-04-08 13:43 ` Joerg Roedel
2014-04-08 15:02 ` Laurent Pinchart
2014-04-09 15:08 ` Joerg Roedel
2014-04-10 23:30 ` Laurent Pinchart
2014-03-08 0:46 ` [PATCH 4/5] iommu/omap: Remove comment about supporting single page mappings only Laurent Pinchart
2014-03-08 0:46 ` [PATCH 5/5] iommu/omap: Fix map protection value handling Laurent Pinchart
[not found] ` <1394239574-2389-6-git-send-email-laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
2014-03-14 0:07 ` Suman Anna
2014-03-14 9:46 ` Laurent Pinchart
2014-03-15 0:16 ` Suman Anna
2014-03-08 11:04 ` [PATCH 0/5] OMAP IOMMU fixes and IOMMU architecture questions Sakari Ailus
2014-03-12 15:26 ` Laurent Pinchart
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