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
All the cache maintainance is already stubbed out when not enabled,
but merging the two allows us to nicely handle the case where
cache maintainance is required for some devices, but not others.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com> # MIPS parts
Various architectures support both coherent and non-coherent dma on a
per-device basis. Move the dma_noncoherent flag from the mips archdata
field to struct device proper to prepare the infrastructure for reuse on
other architectures.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The patch adding the infrastructure failed to actually add the symbol
declaration, oops..
Fixes: faef87723a ("dma-noncoherent: add a arch_sync_dma_for_cpu_all hook")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Currently the code is split over various files with dma- prefixes in the
lib/ and drives/base directories, and the number of files keeps growing.
Move them into a single directory to keep the code together and remove
the file name prefixes. To match the irq infrastructure this directory
is placed under the kernel/ directory.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Christoph Hellwig