linux-toradex.git/include/linux/dma-mapping.h, branch v3.14.3

ARM: 7795/1: mm: dma-mapping: Add dma_max_pfn(dev) helper function

2013-10-31T14:49:24+00:00

Most of the kernel assumes that PFN0 is the start of the physical
memory (RAM). This assumptions is not true on most of the ARM SOCs
and hence and if one try to update the ARM port to follow the assumptions,
we end of breaking the dma bounce limit for few block layer drivers.
One such example is trying to unify the meaning of max*_pfn on ARM
as the bootmem layer expects, breaks few block layer driver dma
bounce limit.

To fix this problem, we introduce dma_max_pfn(dev) generic helper with
a possibility of override from the architecture code. The helper converts
a DMA bitmask of bits to a block PFN number. In all the generic cases,
it is just  "dev->dma_mask >> PAGE_SHIFT" and hence default behavior
is maintained as is.

Subsequent patches will make use of the helper. No functional change.

Cc: Jens Axboe 
Signed-off-by: Santosh Shilimkar 
Signed-off-by: Russell King

DMA-API: provide a helper to setup DMA masks

2013-10-31T14:48:46+00:00

Many drivers contain code such as:

	dev->dma_mask = &dev->coherent_dma_mask;
	dev->coherent_dma_mask = MASK;

Let's move this pattern out of drivers and have the DMA API provide a
helper for it.  This helper uses dma_set_mask_and_coherent() to allow
platform issues to be properly dealt with via dma_set_mask()/
dma_is_supported().

Signed-off-by: Russell King

DMA-API: provide a helper to set both DMA and coherent DMA masks

2013-09-17T14:32:37+00:00

Provide a helper to set both the DMA and coherent DMA masks to the
same value - this avoids duplicated code in a number of drivers,
sometimes with buggy error handling, and also allows us identify
which drivers do things differently.

Signed-off-by: Russell King

drivers:net: Convert dma_alloc_coherent(...__GFP_ZERO) to dma_zalloc_coherent

2013-08-30T01:55:23+00:00

__GFP_ZERO is an uncommon flag and perhaps is better
not used.  static inline dma_zalloc_coherent exists
so convert the uses of dma_alloc_coherent with __GFP_ZERO
to the more common kernel style with zalloc.

Remove memset from the static inline dma_zalloc_coherent
and add just one use of __GFP_ZERO instead.

Trivially reduces the size of the existing uses of
dma_zalloc_coherent.

Realign arguments as appropriate.

Signed-off-by: Joe Perches 
Acked-by: Neil Horman 
Acked-by: Jesse Brandeburg 
Acked-by: Jeff Kirsher 
Signed-off-by: David S. Miller

common: dma-mapping: introduce dma_get_sgtable() function

2012-07-30T10:25:46+00:00

This patch adds dma_get_sgtable() function which is required to let
drivers to share the buffers allocated by DMA-mapping subsystem. Right
now the driver gets a dma address of the allocated buffer and the kernel
virtual mapping for it. If it wants to share it with other device (= map
into its dma address space) it usually hacks around kernel virtual
addresses to get pointers to pages or assumes that both devices share
the DMA address space. Both solutions are just hacks for the special
cases, which should be avoided in the final version of buffer sharing.

To solve this issue in a generic way, a new call to DMA mapping has been
introduced - dma_get_sgtable(). It allocates a scatter-list which
describes the allocated buffer and lets the driver(s) to use it with
other device(s) by calling dma_map_sg() on it.

This patch provides a generic implementation based on virt_to_page()
call. Architectures which require more sophisticated translation might
provide their own get_sgtable() methods.

Signed-off-by: Marek Szyprowski 
Reviewed-by: Kyungmin Park 
Reviewed-by: Daniel Vetter

Merge branch 'for-linus' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping

2012-04-05T00:13:43+00:00

Pull DMA mapping branch from Marek Szyprowski:
 "Short summary for the whole series:

  A few limitations have been identified in the current dma-mapping
  design and its implementations for various architectures.  There exist
  more than one function for allocating and freeing the buffers:
  currently these 3 are used dma_{alloc, free}_coherent,
  dma_{alloc,free}_writecombine, dma_{alloc,free}_noncoherent.

  For most of the systems these calls are almost equivalent and can be
  interchanged.  For others, especially the truly non-coherent ones
  (like ARM), the difference can be easily noticed in overall driver
  performance.  Sadly not all architectures provide implementations for
  all of them, so the drivers might need to be adapted and cannot be
  easily shared between different architectures.  The provided patches
  unify all these functions and hide the differences under the already
  existing dma attributes concept.  The thread with more references is
  available here:

    http://www.spinics.net/lists/linux-sh/msg09777.html

  These patches are also a prerequisite for unifying DMA-mapping
  implementation on ARM architecture with the common one provided by
  dma_map_ops structure and extending it with IOMMU support.  More
  information is available in the following thread:

    http://thread.gmane.org/gmane.linux.kernel.cross-arch/12819

  More works on dma-mapping framework are planned, especially in the
  area of buffer sharing and managing the shared mappings (together with
  the recently introduced dma_buf interface: commit d15bd7ee445d
  "dma-buf: Introduce dma buffer sharing mechanism").

  The patches in the current set introduce a new alloc/free methods
  (with support for memory attributes) in dma_map_ops structure, which
  will later replace dma_alloc_coherent and dma_alloc_writecombine
  functions."

People finally started piping up with support for merging this, so I'm
merging it as the last of the pending stuff from the merge window.
Looks like pohmelfs is going to wait for 3.5 and more external support
for merging.

* 'for-linus' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
  common: DMA-mapping: add NON-CONSISTENT attribute
  common: DMA-mapping: add WRITE_COMBINE attribute
  common: dma-mapping: introduce mmap method
  common: dma-mapping: remove old alloc_coherent and free_coherent methods
  Hexagon: adapt for dma_map_ops changes
  Unicore32: adapt for dma_map_ops changes
  Microblaze: adapt for dma_map_ops changes
  SH: adapt for dma_map_ops changes
  Alpha: adapt for dma_map_ops changes
  SPARC: adapt for dma_map_ops changes
  PowerPC: adapt for dma_map_ops changes
  MIPS: adapt for dma_map_ops changes
  X86 & IA64: adapt for dma_map_ops changes
  common: dma-mapping: introduce generic alloc() and free() methods

common: dma-mapping: introduce mmap method

2012-03-28T14:36:42+00:00

Introduce new generic mmap method with attributes argument.

This method lets drivers to create a userspace mapping for a DMA buffer
in generic, architecture independent way.

Signed-off-by: Marek Szyprowski 
Acked-by: Kyungmin Park 
Reviewed-by: Arnd Bergmann

common: dma-mapping: remove old alloc_coherent and free_coherent methods

2012-03-28T14:36:41+00:00

Remove old, unused alloc_coherent and free_coherent methods from
dma_map_ops structure.

Signed-off-by: Marek Szyprowski 
Acked-by: Kyungmin Park 
Reviewed-by: Arnd Bergmann

common: dma-mapping: introduce generic alloc() and free() methods

2012-03-28T14:36:27+00:00

Introduce new generic alloc and free methods with attributes argument.

Existing alloc_coherent and free_coherent can be implemented on top of the
new calls with NULL attributes argument. Later also dma_alloc_non_coherent
can be implemented using DMA_ATTR_NONCOHERENT attribute as well as
dma_alloc_writecombine with separate DMA_ATTR_WRITECOMBINE attribute.

This way the drivers will get more generic, platform independent way of
allocating dma buffers with specific parameters.

Signed-off-by: Marek Szyprowski 
Acked-by: Kyungmin Park 
Reviewed-by: David Gibson 
Reviewed-by: Arnd Bergmann

ARM: dma-mapping: convert ARCH_HAS_DMA_SET_COHERENT_MASK to kconfig symbol

2012-03-25T19:35:58+00:00

The only users of ARCH_HAS_DMA_SET_COHERENT_MASK are 2 ARM platforms:
ixp4xx and pxa cm_x2xx. We've been getting lucky that the define is
implicitly included before dma-mapping.h, but the removal of io.h broke
things (c334bc1 ARM: make mach/io.h include optional). Since memory.h
is the correct place, but no longer exists, convert the define to a
kconfig entry.

Reported-by: Paul Gortmaker 
Signed-off-by: Rob Herring 
Acked-by: Nicolas Pitre 
Cc: Russell King 
Cc: Imre Kaloz 
Cc: Krzysztof Halasa 
Cc: Eric Miao 
Acked-by: Haojian Zhuang 
Cc: Vinod Koul 
Cc: Dan Williams