Messages in this thread | | | Date | Sun, 2 Dec 2012 15:03:23 +0100 | From | Joerg Roedel <> | Subject | Re: [PATCH 3/4 v5] iommu/fsl: Add iommu domain attributes required by fsl PAMU driver. |
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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?
> +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
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