![Krzysztof Kozlowski](/assets/img/avatar_default.png)
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>
209 lines
5.2 KiB
C
209 lines
5.2 KiB
C
/*
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* Copyright (C) 2009-2010 PetaLogix
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* Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
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*
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* Provide default implementations of the DMA mapping callbacks for
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* directly mapped busses.
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*/
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#include <linux/device.h>
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#include <linux/dma-mapping.h>
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#include <linux/gfp.h>
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#include <linux/dma-debug.h>
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#include <linux/export.h>
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#include <linux/bug.h>
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#define NOT_COHERENT_CACHE
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static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
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dma_addr_t *dma_handle, gfp_t flag,
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unsigned long attrs)
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{
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#ifdef NOT_COHERENT_CACHE
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return consistent_alloc(flag, size, dma_handle);
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#else
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void *ret;
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struct page *page;
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int node = dev_to_node(dev);
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/* ignore region specifiers */
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flag &= ~(__GFP_HIGHMEM);
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page = alloc_pages_node(node, flag, get_order(size));
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if (page == NULL)
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return NULL;
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ret = page_address(page);
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memset(ret, 0, size);
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*dma_handle = virt_to_phys(ret);
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return ret;
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#endif
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}
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static void dma_direct_free_coherent(struct device *dev, size_t size,
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void *vaddr, dma_addr_t dma_handle,
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unsigned long attrs)
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{
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#ifdef NOT_COHERENT_CACHE
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consistent_free(size, vaddr);
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#else
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free_pages((unsigned long)vaddr, get_order(size));
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#endif
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}
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static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
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int nents, enum dma_data_direction direction,
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unsigned long attrs)
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{
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struct scatterlist *sg;
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int i;
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/* FIXME this part of code is untested */
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for_each_sg(sgl, sg, nents, i) {
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sg->dma_address = sg_phys(sg);
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__dma_sync(page_to_phys(sg_page(sg)) + sg->offset,
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sg->length, direction);
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}
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return nents;
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}
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static int dma_direct_dma_supported(struct device *dev, u64 mask)
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{
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return 1;
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}
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static inline dma_addr_t dma_direct_map_page(struct device *dev,
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struct page *page,
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unsigned long offset,
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size_t size,
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enum dma_data_direction direction,
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unsigned long attrs)
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{
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__dma_sync(page_to_phys(page) + offset, size, direction);
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return page_to_phys(page) + offset;
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}
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static inline void dma_direct_unmap_page(struct device *dev,
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dma_addr_t dma_address,
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size_t size,
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enum dma_data_direction direction,
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unsigned long attrs)
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{
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/* There is not necessary to do cache cleanup
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*
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* phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
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* dma_address is physical address
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*/
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__dma_sync(dma_address, size, direction);
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}
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static inline void
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dma_direct_sync_single_for_cpu(struct device *dev,
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dma_addr_t dma_handle, size_t size,
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enum dma_data_direction direction)
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{
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/*
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* It's pointless to flush the cache as the memory segment
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* is given to the CPU
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*/
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if (direction == DMA_FROM_DEVICE)
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__dma_sync(dma_handle, size, direction);
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}
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static inline void
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dma_direct_sync_single_for_device(struct device *dev,
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dma_addr_t dma_handle, size_t size,
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enum dma_data_direction direction)
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{
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/*
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* It's pointless to invalidate the cache if the device isn't
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* supposed to write to the relevant region
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*/
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if (direction == DMA_TO_DEVICE)
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__dma_sync(dma_handle, size, direction);
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}
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static inline void
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dma_direct_sync_sg_for_cpu(struct device *dev,
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struct scatterlist *sgl, int nents,
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enum dma_data_direction direction)
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{
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struct scatterlist *sg;
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int i;
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/* FIXME this part of code is untested */
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if (direction == DMA_FROM_DEVICE)
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for_each_sg(sgl, sg, nents, i)
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__dma_sync(sg->dma_address, sg->length, direction);
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}
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static inline void
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dma_direct_sync_sg_for_device(struct device *dev,
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struct scatterlist *sgl, int nents,
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enum dma_data_direction direction)
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{
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struct scatterlist *sg;
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int i;
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/* FIXME this part of code is untested */
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if (direction == DMA_TO_DEVICE)
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for_each_sg(sgl, sg, nents, i)
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__dma_sync(sg->dma_address, sg->length, direction);
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}
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static
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int dma_direct_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
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void *cpu_addr, dma_addr_t handle, size_t size,
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unsigned long attrs)
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{
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#ifdef CONFIG_MMU
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unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
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unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
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unsigned long off = vma->vm_pgoff;
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unsigned long pfn;
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if (off >= count || user_count > (count - off))
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return -ENXIO;
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#ifdef NOT_COHERENT_CACHE
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vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
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pfn = consistent_virt_to_pfn(cpu_addr);
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#else
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pfn = virt_to_pfn(cpu_addr);
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#endif
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return remap_pfn_range(vma, vma->vm_start, pfn + off,
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vma->vm_end - vma->vm_start, vma->vm_page_prot);
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#else
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return -ENXIO;
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#endif
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}
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struct dma_map_ops dma_direct_ops = {
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.alloc = dma_direct_alloc_coherent,
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.free = dma_direct_free_coherent,
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.mmap = dma_direct_mmap_coherent,
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.map_sg = dma_direct_map_sg,
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.dma_supported = dma_direct_dma_supported,
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.map_page = dma_direct_map_page,
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.unmap_page = dma_direct_unmap_page,
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.sync_single_for_cpu = dma_direct_sync_single_for_cpu,
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.sync_single_for_device = dma_direct_sync_single_for_device,
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.sync_sg_for_cpu = dma_direct_sync_sg_for_cpu,
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.sync_sg_for_device = dma_direct_sync_sg_for_device,
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};
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EXPORT_SYMBOL(dma_direct_ops);
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/* Number of entries preallocated for DMA-API debugging */
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#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
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static int __init dma_init(void)
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{
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dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
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return 0;
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}
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fs_initcall(dma_init);
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