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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>
167 lines
4.0 KiB
C
167 lines
4.0 KiB
C
/*
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* Dynamic DMA mapping support
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*
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* Copyright 2005-2009 Analog Devices Inc.
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*
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* Licensed under the GPL-2 or later
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*/
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#include <linux/types.h>
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#include <linux/gfp.h>
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#include <linux/string.h>
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#include <linux/spinlock.h>
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#include <linux/dma-mapping.h>
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#include <linux/scatterlist.h>
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#include <linux/export.h>
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#include <linux/bitmap.h>
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static spinlock_t dma_page_lock;
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static unsigned long *dma_page;
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static unsigned int dma_pages;
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static unsigned long dma_base;
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static unsigned long dma_size;
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static unsigned int dma_initialized;
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static void dma_alloc_init(unsigned long start, unsigned long end)
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{
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spin_lock_init(&dma_page_lock);
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dma_initialized = 0;
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dma_page = (unsigned long *)__get_free_page(GFP_KERNEL);
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memset(dma_page, 0, PAGE_SIZE);
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dma_base = PAGE_ALIGN(start);
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dma_size = PAGE_ALIGN(end) - PAGE_ALIGN(start);
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dma_pages = dma_size >> PAGE_SHIFT;
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memset((void *)dma_base, 0, DMA_UNCACHED_REGION);
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dma_initialized = 1;
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printk(KERN_INFO "%s: dma_page @ 0x%p - %d pages at 0x%08lx\n", __func__,
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dma_page, dma_pages, dma_base);
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}
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static inline unsigned int get_pages(size_t size)
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{
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return ((size - 1) >> PAGE_SHIFT) + 1;
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}
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static unsigned long __alloc_dma_pages(unsigned int pages)
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{
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unsigned long ret = 0, flags;
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unsigned long start;
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if (dma_initialized == 0)
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dma_alloc_init(_ramend - DMA_UNCACHED_REGION, _ramend);
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spin_lock_irqsave(&dma_page_lock, flags);
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start = bitmap_find_next_zero_area(dma_page, dma_pages, 0, pages, 0);
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if (start < dma_pages) {
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ret = dma_base + (start << PAGE_SHIFT);
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bitmap_set(dma_page, start, pages);
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}
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spin_unlock_irqrestore(&dma_page_lock, flags);
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return ret;
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}
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static void __free_dma_pages(unsigned long addr, unsigned int pages)
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{
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unsigned long page = (addr - dma_base) >> PAGE_SHIFT;
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unsigned long flags;
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if ((page + pages) > dma_pages) {
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printk(KERN_ERR "%s: freeing outside range.\n", __func__);
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BUG();
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}
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spin_lock_irqsave(&dma_page_lock, flags);
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bitmap_clear(dma_page, page, pages);
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spin_unlock_irqrestore(&dma_page_lock, flags);
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}
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static void *bfin_dma_alloc(struct device *dev, size_t size,
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dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
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{
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void *ret;
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ret = (void *)__alloc_dma_pages(get_pages(size));
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if (ret) {
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memset(ret, 0, size);
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*dma_handle = virt_to_phys(ret);
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}
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return ret;
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}
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static void bfin_dma_free(struct device *dev, size_t size, void *vaddr,
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dma_addr_t dma_handle, unsigned long attrs)
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{
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__free_dma_pages((unsigned long)vaddr, get_pages(size));
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}
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/*
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* Streaming DMA mappings
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*/
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void __dma_sync(dma_addr_t addr, size_t size,
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enum dma_data_direction dir)
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{
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__dma_sync_inline(addr, size, dir);
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}
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EXPORT_SYMBOL(__dma_sync);
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static int bfin_dma_map_sg(struct device *dev, struct scatterlist *sg_list,
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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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for_each_sg(sg_list, sg, nents, i) {
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sg->dma_address = (dma_addr_t) sg_virt(sg);
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__dma_sync(sg_dma_address(sg), sg_dma_len(sg), direction);
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}
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return nents;
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}
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static void bfin_dma_sync_sg_for_device(struct device *dev,
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struct scatterlist *sg_list, int nelems,
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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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for_each_sg(sg_list, sg, nelems, i) {
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sg->dma_address = (dma_addr_t) sg_virt(sg);
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__dma_sync(sg_dma_address(sg), sg_dma_len(sg), direction);
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}
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}
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static dma_addr_t bfin_dma_map_page(struct device *dev, struct page *page,
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unsigned long offset, size_t size, enum dma_data_direction dir,
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unsigned long attrs)
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{
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dma_addr_t handle = (dma_addr_t)(page_address(page) + offset);
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_dma_sync(handle, size, dir);
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return handle;
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}
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static inline void bfin_dma_sync_single_for_device(struct device *dev,
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dma_addr_t handle, size_t size, enum dma_data_direction dir)
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{
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_dma_sync(handle, size, dir);
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}
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struct dma_map_ops bfin_dma_ops = {
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.alloc = bfin_dma_alloc,
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.free = bfin_dma_free,
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.map_page = bfin_dma_map_page,
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.map_sg = bfin_dma_map_sg,
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.sync_single_for_device = bfin_dma_sync_single_for_device,
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.sync_sg_for_device = bfin_dma_sync_sg_for_device,
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};
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EXPORT_SYMBOL(bfin_dma_ops);
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