8b31e49d1d
The implementation we just revived has issues, such as using a Kconfig-defined virtual address area in kernel space that nothing actually carves out (and thus will overlap whatever is there), or having some dependencies on being self contained in a single PTE page which adds unnecessary constraints on the kernel virtual address space. This fixes it by using more classic PTE accessors and automatically locating the area for consistent memory, carving an appropriate hole in the kernel virtual address space, leaving only the size of that area as a Kconfig option. It also brings some dma-mask related fixes from the ARM implementation which was almost identical initially but grew its own fixes. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
159 lines
4.1 KiB
C
159 lines
4.1 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(dev, 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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__dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
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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_BIT_MASK(32);
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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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#ifdef CONFIG_NOT_COHERENT_CACHE
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static inline void dma_direct_sync_sg(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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for_each_sg(sgl, sg, nents, i)
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__dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
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}
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static inline void dma_direct_sync_single_range(struct device *dev,
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dma_addr_t dma_handle, unsigned long offset, size_t size,
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enum dma_data_direction direction)
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{
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__dma_sync(bus_to_virt(dma_handle+offset), size, direction);
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}
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#endif
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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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#ifdef CONFIG_NOT_COHERENT_CACHE
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.sync_single_range_for_cpu = dma_direct_sync_single_range,
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.sync_single_range_for_device = dma_direct_sync_single_range,
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.sync_sg_for_cpu = dma_direct_sync_sg,
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.sync_sg_for_device = dma_direct_sync_sg,
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#endif
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};
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EXPORT_SYMBOL(dma_direct_ops);
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