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00085f1efa
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 <k.kozlowski@samsung.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>
Acked-by: Mark Salter <msalter@redhat.com> [c6x]
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> [cris]
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> [drm]
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Joerg Roedel <jroedel@suse.de> [iommu]
Acked-by: Fabien Dessenne <fabien.dessenne@st.com> [bdisp]
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> [vb2-core]
Acked-by: David Vrabel <david.vrabel@citrix.com> [xen]
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [xen swiotlb]
Acked-by: Joerg Roedel <jroedel@suse.de> [iommu]
Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon]
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390]
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> [avr32]
Acked-by: Vineet Gupta <vgupta@synopsys.com> [arc]
Acked-by: Robin Murphy <robin.murphy@arm.com> [arm64 and dma-iommu]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
83 lines
1.9 KiB
C
83 lines
1.9 KiB
C
/*
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* DMA mapping support for platforms lacking IOMMUs.
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*
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* Copyright (C) 2009 Paul Mundt
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/dma-mapping.h>
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#include <linux/io.h>
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static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
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unsigned long offset, size_t size,
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enum dma_data_direction dir,
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unsigned long attrs)
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{
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dma_addr_t addr = page_to_phys(page) + offset;
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WARN_ON(size == 0);
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dma_cache_sync(dev, page_address(page) + offset, size, dir);
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return addr;
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}
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static int nommu_map_sg(struct device *dev, struct scatterlist *sg,
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int nents, enum dma_data_direction dir,
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unsigned long attrs)
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{
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struct scatterlist *s;
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int i;
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WARN_ON(nents == 0 || sg[0].length == 0);
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for_each_sg(sg, s, nents, i) {
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BUG_ON(!sg_page(s));
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dma_cache_sync(dev, sg_virt(s), s->length, dir);
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s->dma_address = sg_phys(s);
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s->dma_length = s->length;
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}
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return nents;
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}
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#ifdef CONFIG_DMA_NONCOHERENT
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static void nommu_sync_single(struct device *dev, dma_addr_t addr,
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size_t size, enum dma_data_direction dir)
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{
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dma_cache_sync(dev, phys_to_virt(addr), size, dir);
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}
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static void nommu_sync_sg(struct device *dev, struct scatterlist *sg,
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int nelems, enum dma_data_direction dir)
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{
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struct scatterlist *s;
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int i;
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for_each_sg(sg, s, nelems, i)
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dma_cache_sync(dev, sg_virt(s), s->length, dir);
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}
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#endif
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struct dma_map_ops nommu_dma_ops = {
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.alloc = dma_generic_alloc_coherent,
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.free = dma_generic_free_coherent,
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.map_page = nommu_map_page,
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.map_sg = nommu_map_sg,
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#ifdef CONFIG_DMA_NONCOHERENT
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.sync_single_for_device = nommu_sync_single,
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.sync_sg_for_device = nommu_sync_sg,
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#endif
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.is_phys = 1,
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};
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void __init no_iommu_init(void)
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{
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if (dma_ops)
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return;
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dma_ops = &nommu_dma_ops;
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}
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