Re: [PATCH 3/4 v5] iommu/fsl: Add iommu domain attributes required by fsl PAMU driver.
From: Joerg Roedel <joro@8bytes.org>
Date: 2012-12-02 14:03:28
Also in:
linux-iommu, lkml
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?
+ * 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?
quoted hunk ↗ jump to hunk
+struct iommu_stash_attribute { + u32 cpu; /* cpu number */ + u32 cache; /* cache to stash to: L1,L2,L3 */ }; struct iommu_domain {@@ -60,6 +95,14 @@ struct iommu_domain { enum iommu_attr { DOMAIN_ATTR_MAX, DOMAIN_ATTR_GEOMETRY, + /* Set the IOMMU hardware stashing + * parameters. + */ + DOMAIN_ATTR_STASH, + /* Explicity enable/disable DMA for a + * particular memory window. + */ + DOMAIN_ATTR_ENABLE, };
When you add implementation specific attributes please add some indication to the names that it is only for PAMU. DOMAIN_ATTR_STASH sounds too generic. Joerg