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 struct dma_attrs *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 struct dma_attrs *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 struct dma_attrs *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 __dma_sync(page_to_phys(sg_page(sg)) + sg->offset, 65 sg->length, direction); 66 } 67 68 return nents; 69 } 70 71 static int dma_direct_dma_supported(struct device *dev, u64 mask) 72 { 73 return 1; 74 } 75 76 static inline dma_addr_t dma_direct_map_page(struct device *dev, 77 struct page *page, 78 unsigned long offset, 79 size_t size, 80 enum dma_data_direction direction, 81 struct dma_attrs *attrs) 82 { 83 __dma_sync(page_to_phys(page) + offset, size, direction); 84 return page_to_phys(page) + offset; 85 } 86 87 static inline void dma_direct_unmap_page(struct device *dev, 88 dma_addr_t dma_address, 89 size_t size, 90 enum dma_data_direction direction, 91 struct dma_attrs *attrs) 92 { 93 /* There is not necessary to do cache cleanup 94 * 95 * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and 96 * dma_address is physical address 97 */ 98 __dma_sync(dma_address, size, direction); 99 } 100 101 static inline void 102 dma_direct_sync_single_for_cpu(struct device *dev, 103 dma_addr_t dma_handle, size_t size, 104 enum dma_data_direction direction) 105 { 106 /* 107 * It's pointless to flush the cache as the memory segment 108 * is given to the CPU 109 */ 110 111 if (direction == DMA_FROM_DEVICE) 112 __dma_sync(dma_handle, size, direction); 113 } 114 115 static inline void 116 dma_direct_sync_single_for_device(struct device *dev, 117 dma_addr_t dma_handle, size_t size, 118 enum dma_data_direction direction) 119 { 120 /* 121 * It's pointless to invalidate the cache if the device isn't 122 * supposed to write to the relevant region 123 */ 124 125 if (direction == DMA_TO_DEVICE) 126 __dma_sync(dma_handle, size, direction); 127 } 128 129 static inline void 130 dma_direct_sync_sg_for_cpu(struct device *dev, 131 struct scatterlist *sgl, int nents, 132 enum dma_data_direction direction) 133 { 134 struct scatterlist *sg; 135 int i; 136 137 /* FIXME this part of code is untested */ 138 if (direction == DMA_FROM_DEVICE) 139 for_each_sg(sgl, sg, nents, i) 140 __dma_sync(sg->dma_address, sg->length, direction); 141 } 142 143 static inline void 144 dma_direct_sync_sg_for_device(struct device *dev, 145 struct scatterlist *sgl, int nents, 146 enum dma_data_direction direction) 147 { 148 struct scatterlist *sg; 149 int i; 150 151 /* FIXME this part of code is untested */ 152 if (direction == DMA_TO_DEVICE) 153 for_each_sg(sgl, sg, nents, i) 154 __dma_sync(sg->dma_address, sg->length, direction); 155 } 156 157 int dma_direct_mmap_coherent(struct device *dev, struct vm_area_struct *vma, 158 void *cpu_addr, dma_addr_t handle, size_t size, 159 struct dma_attrs *attrs) 160 { 161 #ifdef CONFIG_MMU 162 unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; 163 unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT; 164 unsigned long off = vma->vm_pgoff; 165 unsigned long pfn; 166 167 if (off >= count || user_count > (count - off)) 168 return -ENXIO; 169 170 #ifdef NOT_COHERENT_CACHE 171 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 172 pfn = consistent_virt_to_pfn(cpu_addr); 173 #else 174 pfn = virt_to_pfn(cpu_addr); 175 #endif 176 return remap_pfn_range(vma, vma->vm_start, pfn + off, 177 vma->vm_end - vma->vm_start, vma->vm_page_prot); 178 #else 179 return -ENXIO; 180 #endif 181 } 182 183 struct dma_map_ops dma_direct_ops = { 184 .alloc = dma_direct_alloc_coherent, 185 .free = dma_direct_free_coherent, 186 .mmap = dma_direct_mmap_coherent, 187 .map_sg = dma_direct_map_sg, 188 .dma_supported = dma_direct_dma_supported, 189 .map_page = dma_direct_map_page, 190 .unmap_page = dma_direct_unmap_page, 191 .sync_single_for_cpu = dma_direct_sync_single_for_cpu, 192 .sync_single_for_device = dma_direct_sync_single_for_device, 193 .sync_sg_for_cpu = dma_direct_sync_sg_for_cpu, 194 .sync_sg_for_device = dma_direct_sync_sg_for_device, 195 }; 196 EXPORT_SYMBOL(dma_direct_ops); 197 198 /* Number of entries preallocated for DMA-API debugging */ 199 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16) 200 201 static int __init dma_init(void) 202 { 203 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); 204 205 return 0; 206 } 207 fs_initcall(dma_init); 208