linux-toradex.git/include/linux/dma-noncoherent.h, branch v5.6

dma-mapping: drop the dev argument to arch_sync_dma_for_*

2019-11-20T19:31:38+00:00

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

Signed-off-by: Christoph Hellwig 
Suggested-by: Daniel Vetter

dma-direct: provide mmap and get_sgtable method overrides

2019-11-11T09:52:15+00:00

For dma-direct we know that the DMA address is an encoding of the
physical address that we can trivially decode.  Use that fact to
provide implementations that do not need the arch_dma_coherent_to_pfn
architecture hook.  Note that we still can only support mmap of
non-coherent memory only if the architecture provides a way to set an
uncached bit in the page tables.  This must be true for architectures
that use the generic remap helpers, but other architectures can also
manually select it.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Max Filippov

dma-mapping: remove arch_dma_mmap_pgprot

2019-08-29T14:43:22+00:00

arch_dma_mmap_pgprot is used for two things:

 1) to override the "normal" uncached page attributes for mapping
    memory coherent to devices that can't snoop the CPU caches
 2) to provide the special DMA_ATTR_WRITE_COMBINE semantics on older
    arm systems and some mips platforms

Replace one with the pgprot_dmacoherent macro that is already provided
by arm and much simpler to use, and lift the DMA_ATTR_WRITE_COMBINE
handling to common code with an explicit arch opt-in.

Signed-off-by: Christoph Hellwig 
Acked-by: Geert Uytterhoeven 	# m68k
Acked-by: Paul Burton 		# mips

dma-mapping: fix page attributes for dma_mmap_*

2019-08-10T17:52:45+00:00

All the way back to introducing dma_common_mmap we've defaulted to mark
the pages as uncached.  But this is wrong for DMA coherent devices.
Later on DMA_ATTR_WRITE_COMBINE also got incorrect treatment as that
flag is only treated special on the alloc side for non-coherent devices.

Introduce a new dma_pgprot helper that deals with the check for coherent
devices so that only the remapping cases ever reach arch_dma_mmap_pgprot
and we thus ensure no aliasing of page attributes happens, which makes
the powerpc version of arch_dma_mmap_pgprot obsolete and simplifies the
remaining ones.

Note that this means arch_dma_mmap_pgprot is a bit misnamed now, but
we'll phase it out soon.

Fixes: 64ccc9c033c6 ("common: dma-mapping: add support for generic dma_mmap_* calls")
Reported-by: Shawn Anastasio 
Reported-by: Gavin Li 
Signed-off-by: Christoph Hellwig 
Acked-by: Catalin Marinas  # arm64

dma-mapping: mark dma_alloc_need_uncached as __always_inline

2019-07-08T21:19:33+00:00

Without the __always_inline at least i386 configs that have
CONFIG_OPTIMIZE_INLINING set seem fail to inline
dma_alloc_need_uncached, leading to a linker error because of
undefined symbols.

Reported-by: Randy Dunlap 
Signed-off-by: Christoph Hellwig 
Acked-by: Randy Dunlap  # build-tested

dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING in common code

2019-06-25T12:28:05+00:00

DMA_ATTR_NO_KERNEL_MAPPING is generally implemented by allocating
normal cacheable pages or CMA memory, and then returning the page
pointer as the opaque handle.  Lift that code from the xtensa and
generic dma remapping implementations into the generic dma-direct
code so that we don't even call arch_dma_alloc for these allocations.

Signed-off-by: Christoph Hellwig

dma-mapping: add a dma_alloc_need_uncached helper

2019-06-25T06:14:43+00:00

Check if we need to allocate uncached memory for a device given the
allocation flags.  Switch over the uncached segment check to this helper
to deal with architectures that do not support the dma_cache_sync
operation and thus should not returned cacheable memory for
DMA_ATTR_NON_CONSISTENT allocations.

Signed-off-by: Christoph Hellwig

dma-direct: provide generic support for uncached kernel segments

2019-06-03T14:00:08+00:00

A few architectures support uncached kernel segments.  In that case we get
an uncached mapping for a given physica address by using an offset in the
uncached segement.  Implement support for this scheme in the generic
dma-direct code instead of duplicating it in arch hooks.

Signed-off-by: Christoph Hellwig

dma-mapping: add a Kconfig symbol to indicate arch_dma_prep_coherent presence

2019-05-06T13:04:40+00:00

Add a Kconfig symbol that indicates an architecture provides a
arch_dma_prep_coherent implementation, and provide a stub otherwise.

This will allow the generic dma-iommu code to use it while still
allowing to be built for cache coherent architectures.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Robin Murphy

dma-mapping: bypass indirect calls for dma-direct

2018-12-13T20:06:18+00:00

Avoid expensive indirect calls in the fast path DMA mapping
operations by directly calling the dma_direct_* ops if we are using
the directly mapped DMA operations.

Signed-off-by: Christoph Hellwig 
Acked-by: Jesper Dangaard Brouer 
Tested-by: Jesper Dangaard Brouer 
Tested-by: Tony Luck