Messages in this thread | | | Date | Mon, 3 Dec 2012 11:03:43 -0600 | From | Scott Wood <> | Subject | Re: [PATCH 3/4 v5] iommu/fsl: Add iommu domain attributes required by fsl PAMU driver. |
| |
On 12/03/2012 10:57:29 AM, Sethi Varun-B16395 wrote: > > > > -----Original Message----- > > From: iommu-bounces@lists.linux-foundation.org [mailto:iommu- > > bounces@lists.linux-foundation.org] On Behalf Of Joerg Roedel > > Sent: Sunday, December 02, 2012 7:33 PM > > To: Sethi Varun-B16395 > > Cc: linux-kernel@vger.kernel.org; iommu@lists.linux-foundation.org; > Wood > > Scott-B07421; linuxppc-dev@lists.ozlabs.org; Tabi Timur-B04825 > > Subject: Re: [PATCH 3/4 v5] iommu/fsl: Add iommu domain attributes > > required by fsl PAMU driver. > > > > Hmm, we need to work out a good abstraction for this. > > > > On Tue, Nov 20, 2012 at 07:24:56PM +0530, Varun Sethi wrote: > > > Added the following domain attributes required by FSL PAMU driver: > > > 1. Subwindows field added to the iommu domain geometry attribute. > > > > Are the Subwindows mapped with full size or do you map only parts > of the > > subwindows? > > > [Sethi Varun-B16395] It's possible to map a part of the subwindow > i.e. size of the mapping can be less than the sub window size. > > > > + * This attribute indicates number of DMA subwindows supported > by > > > + * the geometry. If there is a single window that maps the > entire > > > + * geometry, attribute must be set to "1". A value of "0" > implies > > > + * that this mechanism is not used at all(normal paging is > used). > > > + * Value other than* "0" or "1" indicates the actual number of > > > + * subwindows. > > > + */ > > > > This semantic is ugly, how about a feature detection mechanism? > > > [Sethi Varun-B16395] A feature mechanism to query the type of IOMMU?
A feature mechanism to determine whether this subwindow mechanism is available, and what the limits are.
-Scott
| |