iommu/io-pgtable: Avoid redundant TLB syncs
authorRobin Murphy <robin.murphy@arm.com>
Tue, 26 Jan 2016 17:13:15 +0000 (17:13 +0000)
committerWill Deacon <will.deacon@arm.com>
Wed, 17 Feb 2016 14:15:09 +0000 (14:15 +0000)
commit88492a4700360a086e55d8874ad786105a5e8b0f
tree6aa702be20bb1c88bc1d03da09a732a63a0339e7
parent507e4c9d194360d07f9cc9ca689a17eb14e370a2
iommu/io-pgtable: Avoid redundant TLB syncs

In certain unmapping situations it is quite possible to end up issuing
back-to-back TLB synchronisations, which at best is a waste of time and
effort, and at worst causes some hardware to get rather confused. Whilst
the pagetable implementations, or the IOMMU drivers, or both, could keep
track of things to avoid this happening, it seems to make the most sense
to prevent code duplication and add some simple state tracking in the
common interface between the two.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
drivers/iommu/io-pgtable.h