On Thu, Nov 24, 2011 at 01:52:33PM +0100, Marek Szyprowski wrote: > In my DMA-mapping IOMMU integration I've used a dma_iommu_mapping structure, > which contains a pointer to iommu domain, a bitmap and a lock. Maybe we > should consider extending iommu domain with allocation bitmap (or other > structure that hold information about used/unused iova ranges)? From the > DMA-mapping (as a IOMMU client) perspective we only need 2 more callbacks > in IOMMU API: alloc_iova_range() and free_iova_range(). > > Each IOMMU implementation can provide these calls based on internal bitmap > allocator which will also cover the issue with reserved ranges. What do you > think about such solution? Hmm, the main point of a generic DMA-mapping implementation is that a common address-allocator will be used. Today every IOMMU driver that implements the DMA-API has its own allocator, this is something to unify between for all drivers. The allocator information can be stored in the default iommu_domain. We need a user-private pointer there, but that is easy to add. Joerg -- AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo, Andrew Bowd Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
