132 строки
3.3 KiB
C
132 строки
3.3 KiB
C
/*
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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 <asm/bug.h>
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#include <asm/abs_addr.h>
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/*
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* Generic direct DMA implementation
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*
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* This implementation supports a per-device offset that can be applied if
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* the address at which memory is visible to devices is not 0. Platform code
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* can set archdata.dma_data to an unsigned long holding the offset. By
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* default the offset is PCI_DRAM_OFFSET.
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*/
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static unsigned long get_dma_direct_offset(struct device *dev)
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{
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if (dev)
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return (unsigned long)dev->archdata.dma_data;
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return PCI_DRAM_OFFSET;
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}
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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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{
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void *ret;
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#ifdef CONFIG_NOT_COHERENT_CACHE
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ret = __dma_alloc_coherent(size, dma_handle, flag);
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if (ret == NULL)
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return NULL;
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*dma_handle += get_dma_direct_offset(dev);
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return ret;
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#else
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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_abs(ret) + get_dma_direct_offset(dev);
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return ret;
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#endif
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}
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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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{
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#ifdef CONFIG_NOT_COHERENT_CACHE
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__dma_free_coherent(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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struct dma_attrs *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(sgl, sg, nents, i) {
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sg->dma_address = sg_phys(sg) + get_dma_direct_offset(dev);
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sg->dma_length = sg->length;
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}
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return nents;
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}
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static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
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int nents, enum dma_data_direction direction,
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struct dma_attrs *attrs)
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{
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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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#ifdef CONFIG_PPC64
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/* Could be improved to check for memory though it better be
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* done via some global so platforms can set the limit in case
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* they have limited DMA windows
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*/
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return mask >= DMA_32BIT_MASK;
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#else
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return 1;
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#endif
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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 dir,
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struct dma_attrs *attrs)
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{
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BUG_ON(dir == DMA_NONE);
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__dma_sync_page(page, offset, size, dir);
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return page_to_phys(page) + offset + get_dma_direct_offset(dev);
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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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struct dma_attrs *attrs)
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{
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}
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struct dma_mapping_ops dma_direct_ops = {
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.alloc_coherent = dma_direct_alloc_coherent,
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.free_coherent = dma_direct_free_coherent,
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.map_sg = dma_direct_map_sg,
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.unmap_sg = dma_direct_unmap_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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};
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EXPORT_SYMBOL(dma_direct_ops);
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