1/* 2 * Copyright (C) 2009-2010 PetaLogix 3 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation 4 * 5 * Provide default implementations of the DMA mapping callbacks for 6 * directly mapped busses. 7 */ 8 9#include <linux/device.h> 10#include <linux/dma-mapping.h> 11#include <linux/gfp.h> 12#include <linux/dma-debug.h> 13#include <asm/bug.h> 14#include <asm/cacheflush.h> 15 16/* 17 * Generic direct DMA implementation 18 * 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. 23 */ 24static inline void __dma_sync_page(unsigned long paddr, unsigned long offset, 25 size_t size, enum dma_data_direction direction) 26{ 27 switch (direction) { 28 case DMA_TO_DEVICE: 29 flush_dcache_range(paddr + offset, paddr + offset + size); 30 break; 31 case DMA_FROM_DEVICE: 32 invalidate_dcache_range(paddr + offset, paddr + offset + size); 33 break; 34 default: 35 BUG(); 36 } 37} 38 39static unsigned long get_dma_direct_offset(struct device *dev) 40{ 41 if (likely(dev)) 42 return (unsigned long)dev->archdata.dma_data; 43 44 return PCI_DRAM_OFFSET; 45} 46 47#define NOT_COHERENT_CACHE 48 49static void *dma_direct_alloc_coherent(struct device *dev, size_t size, 50 dma_addr_t *dma_handle, gfp_t flag) 51{ 52#ifdef NOT_COHERENT_CACHE 53 return consistent_alloc(flag, size, dma_handle); 54#else 55 void *ret; 56 struct page *page; 57 int node = dev_to_node(dev); 58 59 /* ignore region specifiers */ 60 flag &= ~(__GFP_HIGHMEM); 61 62 page = alloc_pages_node(node, flag, get_order(size)); 63 if (page == NULL) 64 return NULL; 65 ret = page_address(page); 66 memset(ret, 0, size); 67 *dma_handle = virt_to_phys(ret) + get_dma_direct_offset(dev); 68 69 return ret; 70#endif 71} 72 73static void dma_direct_free_coherent(struct device *dev, size_t size, 74 void *vaddr, dma_addr_t dma_handle) 75{ 76#ifdef NOT_COHERENT_CACHE 77 consistent_free(size, vaddr); 78#else 79 free_pages((unsigned long)vaddr, get_order(size)); 80#endif 81} 82 83static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, 84 int nents, enum dma_data_direction direction, 85 struct dma_attrs *attrs) 86{ 87 struct scatterlist *sg; 88 int i; 89 90 for_each_sg(sgl, sg, nents, i) { 91 sg->dma_address = sg_phys(sg) + get_dma_direct_offset(dev); 92 __dma_sync_page(page_to_phys(sg_page(sg)), sg->offset, 93 sg->length, direction); 94 } 95 96 return nents; 97} 98 99static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg, 100 int nents, enum dma_data_direction direction, 101 struct dma_attrs *attrs) 102{ 103} 104 105static int dma_direct_dma_supported(struct device *dev, u64 mask) 106{ 107 return 1; 108} 109 110static inline dma_addr_t dma_direct_map_page(struct device *dev, 111 struct page *page, 112 unsigned long offset, 113 size_t size, 114 enum dma_data_direction direction, 115 struct dma_attrs *attrs) 116{ 117 __dma_sync_page(page_to_phys(page), offset, size, direction); 118 return page_to_phys(page) + offset + get_dma_direct_offset(dev); 119} 120 121static inline void dma_direct_unmap_page(struct device *dev, 122 dma_addr_t dma_address, 123 size_t size, 124 enum dma_data_direction direction, 125 struct dma_attrs *attrs) 126{ 127/* There is not necessary to do cache cleanup 128 * 129 * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and 130 * dma_address is physical address 131 */ 132 __dma_sync_page(dma_address, 0 , size, direction); 133} 134 135struct dma_map_ops dma_direct_ops = { 136 .alloc_coherent = dma_direct_alloc_coherent, 137 .free_coherent = dma_direct_free_coherent, 138 .map_sg = dma_direct_map_sg, 139 .unmap_sg = dma_direct_unmap_sg, 140 .dma_supported = dma_direct_dma_supported, 141 .map_page = dma_direct_map_page, 142 .unmap_page = dma_direct_unmap_page, 143}; 144EXPORT_SYMBOL(dma_direct_ops); 145 146/* Number of entries preallocated for DMA-API debugging */ 147#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16) 148 149static int __init dma_init(void) 150{ 151 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); 152 153 return 0; 154} 155fs_initcall(dma_init); 156