Messages in this thread | | | Date | Mon, 6 Jun 2011 12:09:51 +0200 | From | "Roedel, Joerg" <> | Subject | Re: [RFC 0/6] iommu: generic api migration and grouping |
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Hi,
On Thu, Jun 02, 2011 at 06:27:37PM -0400, Ohad Ben-Cohen wrote: > First stab at iommu consolidation: > > - Migrate OMAP's iommu driver to the generic iommu API. With this in hand, > users can now start using the generic iommu layer instead of calling > omap-specific iommu API. > > New code that requires functionality missing from the generic iommu api, > will add that functionality in the generic framework (e.g. adding framework > awareness to multi page sizes, supported by the underlying hardware, will > avoid the otherwise-inevitable code duplication when mapping a memory > region).
The IOMMU-API already supports multiple page-sizes. See the 'order'-parameter of the map/unmap functions.
> Further generalizing of iovmm strongly depends on our broader plans for > providing a generic virtual memory manager and allocation framework > (which, as discussed, should be separated from a specific mapper).
The generic vmm for DMA is called DMA-API :) Any reason for not using that (those reasons should be fixed)?
> iovmm has a mainline user: omap3isp, and therefore must be maintained, > but new potential users will either have to generalize it, or come up > with a different generic framework that will replace it.
Moving to the DMA-API should be considered here. If it is too much work iovmm can stay for a while, but the goal should be to get rid of it and only use the DMA-API.
> - Create a dedicated iommu drivers folder (and put the base iommu code there)
Very good idea.
Joerg
P.S.: Please also Cc the iommu-list (iommu@lists.linux-foundation.org) in the future for IOMMU related patches.
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