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 <linux/export.h> 14 #include <linux/bug.h> 15 16 #define NOT_COHERENT_CACHE 17 18 static void *dma_direct_alloc_coherent(struct device *dev, size_t size, 19 dma_addr_t *dma_handle, gfp_t flag, 20 unsigned long attrs) 21 { 22 #ifdef NOT_COHERENT_CACHE 23 return consistent_alloc(flag, size, dma_handle); 24 #else 25 void *ret; 26 struct page *page; 27 int node = dev_to_node(dev); 28 29 /* ignore region specifiers */ 30 flag &= ~(__GFP_HIGHMEM); 31 32 page = alloc_pages_node(node, flag, get_order(size)); 33 if (page == NULL) 34 return NULL; 35 ret = page_address(page); 36 memset(ret, 0, size); 37 *dma_handle = virt_to_phys(ret); 38 39 return ret; 40 #endif 41 } 42 43 static void dma_direct_free_coherent(struct device *dev, size_t size, 44 void *vaddr, dma_addr_t dma_handle, 45 unsigned long attrs) 46 { 47 #ifdef NOT_COHERENT_CACHE 48 consistent_free(size, vaddr); 49 #else 50 free_pages((unsigned long)vaddr, get_order(size)); 51 #endif 52 } 53 54 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, 55 int nents, enum dma_data_direction direction, 56 unsigned long attrs) 57 { 58 struct scatterlist *sg; 59 int i; 60 61 /* FIXME this part of code is untested */ 62 for_each_sg(sgl, sg, nents, i) { 63 sg->dma_address = sg_phys(sg); 64 65 if (attrs & DMA_ATTR_SKIP_CPU_SYNC) 66 continue; 67 68 __dma_sync(sg_phys(sg), sg->length, direction); 69 } 70 71 return nents; 72 } 73 74 static int dma_direct_dma_supported(struct device *dev, u64 mask) 75 { 76 return 1; 77 } 78 79 static inline dma_addr_t dma_direct_map_page(struct device *dev, 80 struct page *page, 81 unsigned long offset, 82 size_t size, 83 enum dma_data_direction direction, 84 unsigned long attrs) 85 { 86 if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) 87 __dma_sync(page_to_phys(page) + offset, size, direction); 88 return page_to_phys(page) + offset; 89 } 90 91 static inline void dma_direct_unmap_page(struct device *dev, 92 dma_addr_t dma_address, 93 size_t size, 94 enum dma_data_direction direction, 95 unsigned long attrs) 96 { 97 /* There is not necessary to do cache cleanup 98 * 99 * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and 100 * dma_address is physical address 101 */ 102 if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) 103 __dma_sync(dma_address, size, direction); 104 } 105 106 static inline void 107 dma_direct_sync_single_for_cpu(struct device *dev, 108 dma_addr_t dma_handle, size_t size, 109 enum dma_data_direction direction) 110 { 111 /* 112 * It's pointless to flush the cache as the memory segment 113 * is given to the CPU 114 */ 115 116 if (direction == DMA_FROM_DEVICE) 117 __dma_sync(dma_handle, size, direction); 118 } 119 120 static inline void 121 dma_direct_sync_single_for_device(struct device *dev, 122 dma_addr_t dma_handle, size_t size, 123 enum dma_data_direction direction) 124 { 125 /* 126 * It's pointless to invalidate the cache if the device isn't 127 * supposed to write to the relevant region 128 */ 129 130 if (direction == DMA_TO_DEVICE) 131 __dma_sync(dma_handle, size, direction); 132 } 133 134 static inline void 135 dma_direct_sync_sg_for_cpu(struct device *dev, 136 struct scatterlist *sgl, int nents, 137 enum dma_data_direction direction) 138 { 139 struct scatterlist *sg; 140 int i; 141 142 /* FIXME this part of code is untested */ 143 if (direction == DMA_FROM_DEVICE) 144 for_each_sg(sgl, sg, nents, i) 145 __dma_sync(sg->dma_address, sg->length, direction); 146 } 147 148 static inline void 149 dma_direct_sync_sg_for_device(struct device *dev, 150 struct scatterlist *sgl, int nents, 151 enum dma_data_direction direction) 152 { 153 struct scatterlist *sg; 154 int i; 155 156 /* FIXME this part of code is untested */ 157 if (direction == DMA_TO_DEVICE) 158 for_each_sg(sgl, sg, nents, i) 159 __dma_sync(sg->dma_address, sg->length, direction); 160 } 161 162 static 163 int dma_direct_mmap_coherent(struct device *dev, struct vm_area_struct *vma, 164 void *cpu_addr, dma_addr_t handle, size_t size, 165 unsigned long attrs) 166 { 167 #ifdef CONFIG_MMU 168 unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; 169 unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT; 170 unsigned long off = vma->vm_pgoff; 171 unsigned long pfn; 172 173 if (off >= count || user_count > (count - off)) 174 return -ENXIO; 175 176 #ifdef NOT_COHERENT_CACHE 177 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 178 pfn = consistent_virt_to_pfn(cpu_addr); 179 #else 180 pfn = virt_to_pfn(cpu_addr); 181 #endif 182 return remap_pfn_range(vma, vma->vm_start, pfn + off, 183 vma->vm_end - vma->vm_start, vma->vm_page_prot); 184 #else 185 return -ENXIO; 186 #endif 187 } 188 189 const struct dma_map_ops dma_direct_ops = { 190 .alloc = dma_direct_alloc_coherent, 191 .free = dma_direct_free_coherent, 192 .mmap = dma_direct_mmap_coherent, 193 .map_sg = dma_direct_map_sg, 194 .dma_supported = dma_direct_dma_supported, 195 .map_page = dma_direct_map_page, 196 .unmap_page = dma_direct_unmap_page, 197 .sync_single_for_cpu = dma_direct_sync_single_for_cpu, 198 .sync_single_for_device = dma_direct_sync_single_for_device, 199 .sync_sg_for_cpu = dma_direct_sync_sg_for_cpu, 200 .sync_sg_for_device = dma_direct_sync_sg_for_device, 201 }; 202 EXPORT_SYMBOL(dma_direct_ops); 203 204 /* Number of entries preallocated for DMA-API debugging */ 205 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16) 206 207 static int __init dma_init(void) 208 { 209 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); 210 211 return 0; 212 } 213 fs_initcall(dma_init); 214