2 * Copyright (C) 2009-2010 PetaLogix
3 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
5 * Provide default implementations of the DMA mapping callbacks for
6 * directly mapped busses.
9 #include <linux/device.h>
10 #include <linux/dma-mapping.h>
11 #include <linux/gfp.h>
12 #include <linux/dma-debug.h>
14 #include <asm/cacheflush.h>
17 * Generic direct DMA implementation
19 * This implementation supports a per-device offset that can be applied if
20 * the address at which memory is visible to devices is not 0. Platform code
21 * can set archdata.dma_data to an unsigned long holding the offset. By
22 * default the offset is PCI_DRAM_OFFSET.
24 static inline void __dma_sync_page(unsigned long paddr, unsigned long offset,
25 size_t size, enum dma_data_direction direction)
29 flush_dcache_range(paddr + offset, paddr + offset + size);
32 invalidate_dcache_range(paddr + offset, paddr + offset + size);
39 static unsigned long get_dma_direct_offset(struct device *dev)
42 return (unsigned long)dev->archdata.dma_data;
44 return PCI_DRAM_OFFSET; /* FIXME Not sure if is correct */
47 #define NOT_COHERENT_CACHE
49 static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
50 dma_addr_t *dma_handle, gfp_t flag)
52 #ifdef NOT_COHERENT_CACHE
53 return consistent_alloc(flag, size, dma_handle);
57 int node = dev_to_node(dev);
59 /* ignore region specifiers */
60 flag &= ~(__GFP_HIGHMEM);
62 page = alloc_pages_node(node, flag, get_order(size));
65 ret = page_address(page);
67 *dma_handle = virt_to_phys(ret) + get_dma_direct_offset(dev);
73 static void dma_direct_free_coherent(struct device *dev, size_t size,
74 void *vaddr, dma_addr_t dma_handle)
76 #ifdef NOT_COHERENT_CACHE
77 consistent_free(size, vaddr);
79 free_pages((unsigned long)vaddr, get_order(size));
83 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
84 int nents, enum dma_data_direction direction,
85 struct dma_attrs *attrs)
87 struct scatterlist *sg;
90 /* FIXME this part of code is untested */
91 for_each_sg(sgl, sg, nents, i) {
92 sg->dma_address = sg_phys(sg) + get_dma_direct_offset(dev);
93 __dma_sync_page(page_to_phys(sg_page(sg)), sg->offset,
94 sg->length, direction);
100 static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
101 int nents, enum dma_data_direction direction,
102 struct dma_attrs *attrs)
106 static int dma_direct_dma_supported(struct device *dev, u64 mask)
111 static inline dma_addr_t dma_direct_map_page(struct device *dev,
113 unsigned long offset,
115 enum dma_data_direction direction,
116 struct dma_attrs *attrs)
118 __dma_sync_page(page_to_phys(page), offset, size, direction);
119 return page_to_phys(page) + offset + get_dma_direct_offset(dev);
122 static inline void dma_direct_unmap_page(struct device *dev,
123 dma_addr_t dma_address,
125 enum dma_data_direction direction,
126 struct dma_attrs *attrs)
128 /* There is not necessary to do cache cleanup
130 * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
131 * dma_address is physical address
133 __dma_sync_page(dma_address, 0 , size, direction);
136 struct dma_map_ops dma_direct_ops = {
137 .alloc_coherent = dma_direct_alloc_coherent,
138 .free_coherent = dma_direct_free_coherent,
139 .map_sg = dma_direct_map_sg,
140 .unmap_sg = dma_direct_unmap_sg,
141 .dma_supported = dma_direct_dma_supported,
142 .map_page = dma_direct_map_page,
143 .unmap_page = dma_direct_unmap_page,
145 EXPORT_SYMBOL(dma_direct_ops);
147 /* Number of entries preallocated for DMA-API debugging */
148 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
150 static int __init dma_init(void)
152 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
156 fs_initcall(dma_init);