mirror of
https://github.com/torvalds/linux
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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>
76 lines
1.6 KiB
C
76 lines
1.6 KiB
C
/*
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* lib/dma-noop.c
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*
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* Simple DMA noop-ops that map 1:1 with memory
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*/
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#include <linux/export.h>
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#include <linux/mm.h>
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#include <linux/dma-mapping.h>
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#include <linux/scatterlist.h>
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static void *dma_noop_alloc(struct device *dev, size_t size,
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dma_addr_t *dma_handle, gfp_t gfp,
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unsigned long attrs)
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{
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void *ret;
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ret = (void *)__get_free_pages(gfp, get_order(size));
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if (ret)
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*dma_handle = virt_to_phys(ret);
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return ret;
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}
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static void dma_noop_free(struct device *dev, size_t size,
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void *cpu_addr, dma_addr_t dma_addr,
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unsigned long attrs)
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{
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free_pages((unsigned long)cpu_addr, get_order(size));
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}
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static dma_addr_t dma_noop_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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return page_to_phys(page) + offset;
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}
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static int dma_noop_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
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enum dma_data_direction dir,
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unsigned long attrs)
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{
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int i;
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struct scatterlist *sg;
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for_each_sg(sgl, sg, nents, i) {
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void *va;
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BUG_ON(!sg_page(sg));
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va = sg_virt(sg);
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sg_dma_address(sg) = (dma_addr_t)virt_to_phys(va);
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sg_dma_len(sg) = sg->length;
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}
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return nents;
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}
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static int dma_noop_mapping_error(struct device *dev, dma_addr_t dma_addr)
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{
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return 0;
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}
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static int dma_noop_supported(struct device *dev, u64 mask)
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{
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return 1;
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}
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struct dma_map_ops dma_noop_ops = {
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.alloc = dma_noop_alloc,
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.free = dma_noop_free,
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.map_page = dma_noop_map_page,
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.map_sg = dma_noop_map_sg,
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.mapping_error = dma_noop_mapping_error,
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.dma_supported = dma_noop_supported,
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};
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EXPORT_SYMBOL(dma_noop_ops);
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