tree 610d7a3914ac948545c4cc890a84a952849824a1
parent ff2ed96dde3b30d8f1b2ab0d9b164140f2278e6e
author Robin Murphy <Robin.Murphy@arm.com> 1438195569 +0100
committer Will Deacon <will.deacon@arm.com> 1438868139 +0100

iommu/io-pgtable-arm: Centralise sync points

With all current users now opted in to DMA API operations, make the
iommu_dev pointer mandatory, rendering the flush_pgtable callback
redundant for cache maintenance. However, since the DMA calls could be
nops in the case of a coherent IOMMU, we still need to ensure the page
table updates are fully synchronised against a subsequent page table
walk. In the unmap path, the TLB sync will usually need to do this
anyway, so just cement that requirement; in the map path which may
consist solely of cacheable memory writes (in the coherent case),
insert an appropriate barrier at the end of the operation, and obviate
the need to call flush_pgtable on every individual update for
synchronisation.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
[will: slight clarification to tlb_sync comment]
Signed-off-by: Will Deacon <will.deacon@arm.com>