Move more nitty gritty DMA implementation details into the common
internal header.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Most of dma-debug.h is not required by anything outside of kernel/dma.
Move the four declarations needed by dma-mappin.h or dma-ops providers
into dma-mapping.h and dma-map-ops.h, and move the remainder of the
file to kernel/dma/debug.h.

Signed-off-by: Christoph Hellwig <hch@lst.de>

These are pure cache maintainance routines, so drop the unused
struct device argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>

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

Switch to the generic noncoherent direct mapping implementation.

This removes the direction-based optimizations in
sync_{single,sg}_for_{cpu,device} which were marked untestested and
do not match the usually very well tested {un,}map_{single,sg}
implementations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

Most mainstream architectures are using 65536 entries, so lets stick to
that.  If someone is really desperate to override it that can still be
done through <asm/dma-mapping.h>, but I'd rather see a really good
rationale for that.

dma_debug_init is now called as a core_initcall, which for many
architectures means much earlier, and provides dma-debug functionality
earlier in the boot process.  This should be safe as it only relies
on the memory allocator already being available.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>

Signed-off-by: Christoph Hellwig <hch@lst.de>

Always returning 1 is the same behavior as not supplying a method at all.

Signed-off-by: Christoph Hellwig <hch@lst.de>

This frees the dma_direct_* namespace for a generic implementation.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Pull dma-mapping updates from Christoph Hellwig:

 - turn dma_cache_sync into a dma_map_ops instance and remove
   implementation that purely are dead because the architecture doesn't
   support noncoherent allocations

 - add a flag for busses that need DMA configuration (Robin Murphy)

* tag 'dma-mapping-4.15' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: turn dma_cache_sync into a dma_map_ops method
  sh: make dma_cache_sync a no-op
  xtensa: make dma_cache_sync a no-op
  unicore32: make dma_cache_sync a no-op
  powerpc: make dma_cache_sync a no-op
  mn10300: make dma_cache_sync a no-op
  microblaze: make dma_cache_sync a no-op
  ia64: make dma_cache_sync a no-op
  frv: make dma_cache_sync a no-op
  x86: make dma_cache_sync a no-op
  floppy: consolidate the dummy fd_cacheflush definition
  drivers: flag buses which demand DMA configuration