This is a step in the right direction.  Cell allows each device to
have its own io pagesize, from among those that the io controller
supports (4k, 64k, 1m,16m).  This limitation of the current iommu
code that you try to address here has caused me to use platform
specific dma alloc routines.

Are devices -actually- using different page sizes ? AFAIK, for your
platform, you are using a 4k base page size, thus there is very little
point (in fact, it's more like a problem) to have an IO mapping using
larger page sizes.

In any case, read my reply to Linas, I'm proposing a scheme where each
iommu_table instance could have its own page size, in which case you can
just create a table instance per device.

Ben.