dma-mapping: consolidate the dma mmap implementations
The only functional differences (modulo a few missing fixes in the arch
code) is that architectures without coherent caches need a hook to
convert a virtual or dma address into a pfn, given that we don't have
the kernel linear mapping available for the otherwise easy virt_to_page
call. As a side effect we can support mmap of the per-device coherent
area even on architectures not providing the callback, and we make
previous dangerous default methods dma_common_mmap actually save for
non-coherent architectures by rejecting it without the right helper.
In addition to that we need a hook so that some architectures can
override the protection bits when mmaping a dma coherent allocations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com> # MIPS parts
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index ca03694..3d9bdec 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -9,6 +9,7 @@
config ARC
def_bool y
select ARC_TIMERS
+ select ARCH_HAS_DMA_COHERENT_TO_PFN
select ARCH_HAS_PTE_SPECIAL
select ARCH_HAS_SYNC_DMA_FOR_CPU
select ARCH_HAS_SYNC_DMA_FOR_DEVICE
@@ -18,7 +19,6 @@
select CLONE_BACKWARDS
select COMMON_CLK
select DMA_DIRECT_OPS
- select DMA_NONCOHERENT_MMAP
select GENERIC_ATOMIC64 if !ISA_ARCV2 || !(ARC_HAS_LL64 && ARC_HAS_LLSC)
select GENERIC_CLOCKEVENTS
select GENERIC_FIND_FIRST_BIT