On 12/03/2012 10:57:29 AM, Sethi Varun-B16395 wrote:
=20
=20
quoted
-----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; =20
Wood
quoted
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:
quoted
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 =20
of the
quoted
subwindows?
[Sethi Varun-B16395] It's possible to map a part of the subwindow =20
i.e. size of the mapping can be less than the sub window size.
=20
quoted
quoted
+ * This attribute indicates number of DMA subwindows supported =20
by
quoted
quoted
+ * the geometry. If there is a single window that maps the =20
entire
quoted
quoted
+ * geometry, attribute must be set to "1". A value of "0" =20
implies
quoted
quoted
+ * that this mechanism is not used at all(normal paging is =20
used).
quoted
quoted
+ * 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 =20
available, and what the limits are.
-Scott=
-----Original Message-----
From: Wood Scott-B07421
Sent: Monday, December 03, 2012 10:34 PM
To: Sethi Varun-B16395
Cc: Joerg Roedel; 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
On 12/03/2012 10:57:29 AM, Sethi Varun-B16395 wrote:
quoted
quoted
-----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
quoted
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:
quoted
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
quoted
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.
quoted
quoted
+ * This attribute indicates number of DMA subwindows
supported
quoted
by
quoted
quoted
+ * the geometry. If there is a single window that maps the
entire
quoted
quoted
+ * geometry, attribute must be set to "1". A value of "0"
implies
quoted
quoted
+ * that this mechanism is not used at all(normal paging is
used).
quoted
quoted
+ * Value other than* "0" or "1" indicates the actual number
of
quoted
quoted
quoted
+ * subwindows.
+ */
This semantic is ugly, how about a feature detection mechanism?
[Sethi Varun-B16395] A feature mechanism to query the type of IOMMU?
=20
A feature mechanism to determine whether this subwindow mechanism is
available, and what the limits are.
=20
So, we use the IOMMU capability interface to find out if IOMMU supports sub=
windows or not, right? But still number of sub windows would be specified =
as a part of the geometry and the valid value for sub windows would 0,1 or=
actual number of sub windows.
-Varun
=20