tree 046095a0cce051a471c7af93784c024c29a4f99b
parent f637a49e507c88354ab32b5d914e06acfb7ee00d
author Benjamin Herrenschmidt <benh@kernel.crashing.org> 1243396233 +1000
committer Benjamin Herrenschmidt <benh@kernel.crashing.org> 1243406039 +1000

powerpc: Fix up dma_alloc_coherent() on platforms without cache coherency.

The implementation we just revived has issues, such as using a
Kconfig-defined virtual address area in kernel space that nothing
actually carves out (and thus will overlap whatever is there),
or having some dependencies on being self contained in a single
PTE page which adds unnecessary constraints on the kernel virtual
address space.

This fixes it by using more classic PTE accessors and automatically
locating the area for consistent memory, carving an appropriate hole
in the kernel virtual address space, leaving only the size of that
area as a Kconfig option. It also brings some dma-mask related fixes
from the ARM implementation which was almost identical initially but
grew its own fixes.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>