-----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.
=20
Hmm, we need to work out a good abstraction for this.
=20
On Tue, Nov 20, 2012 at 07:24:56PM +0530, Varun Sethi wrote:

quoted

Added the following domain attributes required by FSL PAMU driver:
1. Subwindows field added to the iommu domain geometry attribute.

=20
Are the Subwindows mapped with full size or do you map only parts of the
subwindows?
=20

[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.

quoted

+	 * 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.
+	 */

=20
This semantic is ugly, how about a feature detection mechanism?
=20

[Sethi Varun-B16395] A feature mechanism to query the type of IOMMU?

-Varun