linux-toradex.git/include/linux/swiotlb.h, branch v4.13-rc5

swiotlb: Export swiotlb_max_segment to users

2017-01-06T18:00:01+00:00

So they can figure out what is the optimal number of pages
that can be contingously stitched together without fear of
bounce buffer.

We also expose an mechanism for sub-users of SWIOTLB API, such
as Xen-SWIOTLB to set the max segment value. And lastly
if swiotlb=force is set (which mandates we bounce buffer everything)
we set max_segment so at least we can bounce buffer one 4K page
instead of a giant 512KB one for which we may not have space.

Signed-off-by: Konrad Rzeszutek Wilk 
Reported-and-Tested-by: Juergen Gross

swiotlb: Add swiotlb=noforce debug option

2016-12-19T14:05:20+00:00

On architectures like arm64, swiotlb is tied intimately to the core
architecture DMA support. In addition, ZONE_DMA cannot be disabled.

To aid debugging and catch devices not supporting DMA to memory outside
the 32-bit address space, add a kernel command line option
"swiotlb=noforce", which disables the use of bounce buffers.
If specified, trying to map memory that cannot be used with DMA will
fail, and a rate-limited warning will be printed.

Note that io_tlb_nslabs is set to 1, which is the minimal supported
value.

Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Konrad Rzeszutek Wilk

swiotlb: Convert swiotlb_force from int to enum

2016-12-19T14:05:20+00:00

Convert the flag swiotlb_force from an int to an enum, to prepare for
the advent of more possible values.

Suggested-by: Konrad Rzeszutek Wilk 
Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Konrad Rzeszutek Wilk

swiotlb: Add support for DMA_ATTR_SKIP_CPU_SYNC

2016-11-07T20:06:33+00:00

As a first step to making DMA_ATTR_SKIP_CPU_SYNC apply to architectures
beyond just ARM I need to make it so that the swiotlb will respect the
flag.  In order to do that I also need to update the swiotlb-xen since it
heavily makes use of the functionality.

Cc: Konrad Rzeszutek Wilk 
Signed-off-by: Alexander Duyck 
Signed-off-by: Konrad Rzeszutek Wilk

swiotlb: Drop unused functions swiotlb_map_sg and swiotlb_unmap_sg

2016-11-07T20:06:31+00:00

There are no users for swiotlb_map_sg or swiotlb_unmap_sg so we might as
well just drop them.

Signed-off-by: Alexander Duyck 
Acked-by:  Christoph Hellwig 
Signed-off-by: Konrad Rzeszutek Wilk

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

swiotlb: Make linux/swiotlb.h standalone includible

2016-01-20T22:29:52+00:00

This header file uses the enum dma_data_direction and struct page types
without explicitly including the corresponding header files. This makes
it rely on the includer to have included the proper headers before.

To fix this, include linux/dma-direction.h and forward-declare struct
page. The swiotlb_free() function is also annotated __init, therefore
requires linux/init.h to be included as well.

Signed-off-by: Thierry Reding 
Signed-off-by: Konrad Rzeszutek Wilk

x86: enable DMA CMA with swiotlb

2014-06-04T23:53:57+00:00

The DMA Contiguous Memory Allocator support on x86 is disabled when
swiotlb config option is enabled.  So DMA CMA is always disabled on
x86_64 because swiotlb is always enabled.  This attempts to support for
DMA CMA with enabling swiotlb config option.

The contiguous memory allocator on x86 is integrated in the function
dma_generic_alloc_coherent() which is .alloc callback in nommu_dma_ops
for dma_alloc_coherent().

x86_swiotlb_alloc_coherent() which is .alloc callback in swiotlb_dma_ops
tries to allocate with dma_generic_alloc_coherent() firstly and then
swiotlb_alloc_coherent() is called as a fallback.

The main part of supporting DMA CMA with swiotlb is that changing
x86_swiotlb_free_coherent() which is .free callback in swiotlb_dma_ops
for dma_free_coherent() so that it can distinguish memory allocated by
dma_generic_alloc_coherent() from one allocated by
swiotlb_alloc_coherent() and release it with dma_generic_free_coherent()
which can handle contiguous memory.  This change requires making
is_swiotlb_buffer() global function.

This also needs to change .free callback in the dma_map_ops for amd_gart
and sta2x11, because these dma_ops are also using
dma_generic_alloc_coherent().

Signed-off-by: Akinobu Mita 
Acked-by: Marek Szyprowski 
Acked-by: Konrad Rzeszutek Wilk 
Cc: David Woodhouse 
Cc: Don Dutile 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: Andi Kleen 
Cc: Yinghai Lu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

x86, kdump: Set crashkernel_low automatically

2013-04-17T19:35:32+00:00

Chao said that kdump does does work well on his system on 3.8
without extra parameter, even iommu does not work with kdump.
And now have to append crashkernel_low=Y in first kernel to make
kdump work.

We have now modified crashkernel=X to allocate memory beyong 4G (if
available) and do not allocate low range for crashkernel if the user
does not specify that with crashkernel_low=Y.  This causes regression
if iommu is not enabled.  Without iommu, swiotlb needs to be setup in
first 4G and there is no low memory available to second kernel.

Set crashkernel_low automatically if the user does not specify that.

For system that does support IOMMU with kdump properly, user could
specify crashkernel_low=0 to save that 72M low ram.

-v3: add swiotlb_size() according to Konrad.
-v4: add comments what 8M is for according to hpa.
     also update more crashkernel_low= in kernel-parameters.txt
-v5: update changelog according to Vivek.
-v6: Change description about swiotlb referring according to HATAYAMA.

Reported-by: WANG Chao 
Tested-by: WANG Chao 
Signed-off-by: Yinghai Lu 
Link: http://lkml.kernel.org/r/1366089828-19692-2-git-send-email-yinghai@kernel.org
Acked-by: Vivek Goyal 
Signed-off-by: H. Peter Anvin

x86: Don't panic if can not alloc buffer for swiotlb

2013-01-30T03:36:53+00:00

Normal boot path on system with iommu support:
swiotlb buffer will be allocated early at first and then try to initialize
iommu, if iommu for intel or AMD could setup properly, swiotlb buffer
will be freed.

The early allocating is with bootmem, and could panic when we try to use
kdump with buffer above 4G only, or with memmap to limit mem under 4G.
for example: memmap=4095M$1M to remove memory under 4G.

According to Eric, add _nopanic version and no_iotlb_memory to fail
map single later if swiotlb is still needed.

-v2: don't pass nopanic, and use -ENOMEM return value according to Eric.
     panic early instead of using swiotlb_full to panic...according to Eric/Konrad.
-v3: make swiotlb_init to be notpanic, but will affect:
     arm64, ia64, powerpc, tile, unicore32, x86.
-v4: cleanup swiotlb_init by removing swiotlb_init_with_default_size.

Suggested-by: Eric W. Biederman 
Signed-off-by: Yinghai Lu 
Link: http://lkml.kernel.org/r/1359058816-7615-36-git-send-email-yinghai@kernel.org
Reviewed-and-tested-by: Konrad Rzeszutek Wilk 
Cc: Joerg Roedel 
Cc: Ralf Baechle 
Cc: Jeremy Fitzhardinge 
Cc: Kyungmin Park 
Cc: Marek Szyprowski 
Cc: Arnd Bergmann 
Cc: Andrzej Pietrasiewicz 
Cc: linux-mips@linux-mips.org
Cc: xen-devel@lists.xensource.com
Cc: virtualization@lists.linux-foundation.org
Cc: Shuah Khan 
Signed-off-by: H. Peter Anvin