linux.git/Documentation/DMA-API.txt, branch v4.13-rc2

DMA-API.txt: standardize document format

2017-07-14T19:51:32+00:00

Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Fix some title marks to match ReST;
- use :Author: for author name;
- foo_ is an hyperlink. Get rid of it;
- Mark literal blocks as such;
- Use tables on some places that are almost using the
  table format.

Signed-off-by: Mauro Carvalho Chehab 
Signed-off-by: Jonathan Corbet

Documentation: DMA API: fix a typo in a function name

2017-06-05T21:57:02+00:00

Correct the typo, the wrongly typed function does not exist.

Fixes: 6c9c6d6301287e ("dma-debug: New interfaces to debug dma mapping errors")
Signed-off-by: Wolfram Sang 
Signed-off-by: Jonathan Corbet

dma-mapping: add dma_{map,unmap}_resource

2016-09-26T16:46:41+00:00

Map/Unmap a device MMIO resource from a physical address. If no dma_map_ops
method is available the operation is a no-op.

Signed-off-by: Niklas Söderlund 
Acked-by: Arnd Bergmann 
Signed-off-by: Vinod Koul

dma-mapping: use unsigned long for dma_attrs

2016-08-04T12:50:07+00:00

The dma-mapping core and the implementations do not change the DMA
attributes passed by pointer.  Thus the pointer can point to const data.
However the attributes do not have to be a bitfield.  Instead unsigned
long will do fine:

1. This is just simpler.  Both in terms of reading the code and setting
   attributes.  Instead of initializing local attributes on the stack
   and passing pointer to it to dma_set_attr(), just set the bits.

2. It brings safeness and checking for const correctness because the
   attributes are passed by value.

Semantic patches for this change (at least most of them):

    virtual patch
    virtual context

    @r@
    identifier f, attrs;

    @@
    f(...,
    - struct dma_attrs *attrs
    + unsigned long attrs
    , ...)
    {
    ...
    }

    @@
    identifier r.f;
    @@
    f(...,
    - NULL
    + 0
     )

and

    // Options: --all-includes
    virtual patch
    virtual context

    @r@
    identifier f, attrs;
    type t;

    @@
    t f(..., struct dma_attrs *attrs);

    @@
    identifier r.f;
    @@
    f(...,
    - NULL
    + 0
     )

Link: http://lkml.kernel.org/r/1468399300-5399-2-git-send-email-k.kozlowski@samsung.com
Signed-off-by: Krzysztof Kozlowski 
Acked-by: Vineet Gupta 
Acked-by: Robin Murphy 
Acked-by: Hans-Christian Noren Egtvedt 
Acked-by: Mark Salter  [c6x]
Acked-by: Jesper Nilsson  [cris]
Acked-by: Daniel Vetter  [drm]
Reviewed-by: Bart Van Assche 
Acked-by: Joerg Roedel  [iommu]
Acked-by: Fabien Dessenne  [bdisp]
Reviewed-by: Marek Szyprowski  [vb2-core]
Acked-by: David Vrabel  [xen]
Acked-by: Konrad Rzeszutek Wilk  [xen swiotlb]
Acked-by: Joerg Roedel  [iommu]
Acked-by: Richard Kuo  [hexagon]
Acked-by: Geert Uytterhoeven  [m68k]
Acked-by: Gerald Schaefer  [s390]
Acked-by: Bjorn Andersson 
Acked-by: Hans-Christian Noren Egtvedt  [avr32]
Acked-by: Vineet Gupta  [arc]
Acked-by: Robin Murphy  [arm64 and dma-iommu]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

DMA-API: fix confusing sentence in Documentation/DMA-API.txt

2016-01-12T01:29:00+00:00

Change the phrase "handed off to the driver" to "handed off to the
device" as in the paragraph below.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Jonathan Corbet

dma: remove external references to dma_supported

2015-11-09T23:11:24+00:00

Signed-off-by: Christoph Hellwig 
Acked-by: Greg Kroah-Hartman 
Cc: Alan Stern 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Documentation: DMA API: Be more explicit that nents is always the same

2015-09-24T21:50:06+00:00

The nents argument to the DMA API functions operating on scatterlists is
always the same. The documentation used different argument names and the
matter was not mentioned in Documentation/DMA-API-HOWTO.txt at all. Fix
these.

Signed-off-by: Sakari Ailus 
Signed-off-by: Jonathan Corbet

mm: add dma_pool_zalloc() call to DMA API

2015-09-08T22:35:28+00:00

Add a wrapper function for dma_pool_alloc() to get zeroed memory.

Signed-off-by: Sean O. Stalley 
Cc: Vinod Koul 
Cc: Bjorn Helgaas 
Cc: Gilles Muller 
Cc: Nicolas Palix 
Cc: Michal Marek 
Cc: Sebastian Andrzej Siewior 
Cc: Jonathan Corbet 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

PCI: Add pci_bus_addr_t

2015-05-29T22:21:45+00:00

David Ahern reported that d63e2e1f3df9 ("sparc/PCI: Clip bridge windows
to fit in upstream windows") fails to boot on sparc/T5-8:

  pci 0000:06:00.0: reg 0x184: can't handle BAR above 4GB (bus address 0x110204000)

The problem is that sparc64 assumed that dma_addr_t only needed to hold DMA
addresses, i.e., bus addresses returned via the DMA API (dma_map_single(),
etc.), while the PCI core assumed dma_addr_t could hold *any* bus address,
including raw BAR values.  On sparc64, all DMA addresses fit in 32 bits, so
dma_addr_t is a 32-bit type.  However, BAR values can be 64 bits wide, so
they don't fit in a dma_addr_t.  d63e2e1f3df9 added new checking that
tripped over this mismatch.

Add pci_bus_addr_t, which is wide enough to hold any PCI bus address,
including both raw BAR values and DMA addresses.  This will be 64 bits
on 64-bit platforms and on platforms with a 64-bit dma_addr_t.  Then
dma_addr_t only needs to be wide enough to hold addresses from the DMA API.

[bhelgaas: changelog, bugzilla, Kconfig to ensure pci_bus_addr_t is at
least as wide as dma_addr_t, documentation]
Fixes: d63e2e1f3df9 ("sparc/PCI: Clip bridge windows to fit in upstream windows")
Fixes: 23b13bc76f35 ("PCI: Fail safely if we can't handle BARs larger than 4GB")
Link: http://lkml.kernel.org/r/CAE9FiQU1gJY1LYrxs+ma5LCTEEe4xmtjRG0aXJ9K_Tsu+m9Wuw@mail.gmail.com
Link: http://lkml.kernel.org/r/1427857069-6789-1-git-send-email-yinghai@kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=96231
Reported-by: David Ahern 
Tested-by: David Ahern 
Signed-off-by: Yinghai Lu 
Signed-off-by: Bjorn Helgaas 
Acked-by: David S. Miller 
CC: stable@vger.kernel.org	# v3.19+

DMA-API: Capitalize "CPU" consistently

2014-05-26T23:28:27+00:00

Sometimes we used "cpu," other times "CPU."  Use "CPU" consistently.

Suggested-by: Randy Dunlap 
Signed-off-by: Bjorn Helgaas