kernel/git/stable/linux.git/Documentation/DMA-attributes.txt, branch master

docs: move DMA kAPI to Documentation/core-api

2020-05-15T17:51:54+00:00

Move those files to the core-api, where they belong, renaming them to ReST and adding to the core API index file. Signed-off-by: Mauro Carvalho Chehab Link: https://lore.kernel.org/r/a1517185418cb9d987f566ef85a5dd5c7c99f34e.1588345503.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet

dma-mapping: remove the DMA_ATTR_WRITE_BARRIER flag

2019-11-14T16:01:54+00:00

This flag is not implemented by any backend and only set by the ib_umem module in a single instance. Link: https://lore.kernel.org/r/20191113073214.9514-2-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe Signed-off-by: Jason Gunthorpe

DMA-attributes.txt: standardize document format

2017-07-14T19:51:33+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: This file is almost on the standard format. All it needs to be parsed by Sphinx is to fix its main title and add a few blank lines. Yet, it is worth to replace NOTE: by the corresponding ReST markup. While here, remove the extra "---" from a subtitle. Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Jonathan Corbet

common: DMA-mapping: add DMA_ATTR_PRIVILEGED attribute

2017-01-19T15:56:19+00:00

This patch adds the DMA_ATTR_PRIVILEGED attribute to the DMA-mapping subsystem. Some advanced peripherals such as remote processors and GPUs perform accesses to DMA buffers in both privileged "supervisor" and unprivileged "user" modes. This attribute is used to indicate to the DMA-mapping subsystem that the buffer is fully accessible at the elevated privilege level (and ideally inaccessible or at least read-only at the lesser-privileged levels). Cc: linux-doc@vger.kernel.org Reviewed-by: Robin Murphy Tested-by: Robin Murphy Acked-by: Will Deacon Signed-off-by: Mitchel Humpherys Signed-off-by: Will Deacon

dma-mapping: introduce the DMA_ATTR_NO_WARN attribute

2016-10-11T22:06:32+00:00

Introduce the DMA_ATTR_NO_WARN attribute, and document it. Link: http://lkml.kernel.org/r/1470092390-25451-2-git-send-email-mauricfo@linux.vnet.ibm.com Signed-off-by: Mauricio Faria de Oliveira Cc: Keith Busch Cc: Jens Axboe Cc: Benjamin Herrenschmidt Cc: Michael Ellerman Cc: Krzysztof Kozlowski Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

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

ARM: 8506/1: common: DMA-mapping: add DMA_ATTR_ALLOC_SINGLE_PAGES attribute

2016-02-11T15:33:38+00:00

This patch adds the DMA_ATTR_ALLOC_SINGLE_PAGES attribute to the DMA-mapping subsystem. This attribute can be used as a hint to the DMA-mapping subsystem that it's likely not worth it to try to allocate large pages behind the scenes. Large pages are likely to make an IOMMU TLB work more efficiently but may not be worth it. See the Documentation contained in this patch for more details about this attribute and when to use it. Note that the name of the hint (DMA_ATTR_ALLOC_SINGLE_PAGES) is loosely based on the name MADV_NOHUGEPAGE. Just as there is MADV_NOHUGEPAGE vs. MADV_HUGEPAGE we could also add an "opposite" attribute to DMA_ATTR_ALLOC_SINGLE_PAGES. Without having the "opposite" attribute the lack of DMA_ATTR_ALLOC_SINGLE_PAGES means "use your best judgement about whether to use small pages or large pages". Signed-off-by: Douglas Anderson Acked-by: Marek Szyprowski Reviewed-by: Robin Murphy Tested-by: Javier Martinez Canillas Signed-off-by: Russell King

doc: spelling error changes

2014-05-05T13:32:05+00:00

Fixed multiple spelling errors. Acked-by: Randy Dunlap Signed-off-by: Carlos E. Garcia Signed-off-by: Jiri Kosina

doc: Documentation/DMA-attributes.txt fix typo

2013-10-14T13:50:53+00:00

Fix some typos in Documentation/DMA-attributes.txt. Signed-off-by: Xishi Qiu Acked-by: Rob Landley Signed-off-by: Jiri Kosina

common: DMA-mapping: add DMA_ATTR_FORCE_CONTIGUOUS attribute

2012-11-29T11:30:34+00:00

This patch adds DMA_ATTR_FORCE_CONTIGUOUS attribute to the DMA-mapping subsystem. By default DMA-mapping subsystem is allowed to assemble the buffer allocated by dma_alloc_attrs() function from individual pages if it can be mapped as contiguous chunk into device dma address space. By specifing this attribute the allocated buffer is forced to be contiguous also in physical memory. Signed-off-by: Marek Szyprowski