1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2009-2010 PetaLogix 4 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation 5 * 6 * Provide default implementations of the DMA mapping callbacks for 7 * directly mapped busses. 8 */ 9 10 #include <linux/device.h> 11 #include <linux/dma-mapping.h> 12 #include <linux/gfp.h> 13 #include <linux/dma-debug.h> 14 #include <linux/export.h> 15 #include <linux/bug.h> 16 #include <asm/cacheflush.h> 17 18 #define NOT_COHERENT_CACHE 19 20 static void *dma_direct_alloc_coherent(struct device *dev, size_t size, 21 dma_addr_t *dma_handle, gfp_t flag, 22 unsigned long attrs) 23 { 24 #ifdef NOT_COHERENT_CACHE 25 return consistent_alloc(flag, size, dma_handle); 26 #else 27 void *ret; 28 struct page *page; 29 int node = dev_to_node(dev); 30 31 /* ignore region specifiers */ 32 flag &= ~(__GFP_HIGHMEM); 33 34 page = alloc_pages_node(node, flag, get_order(size)); 35 if (page == NULL) 36 return NULL; 37 ret = page_address(page); 38 memset(ret, 0, size); 39 *dma_handle = virt_to_phys(ret); 40 41 return ret; 42 #endif 43 } 44 45 static void dma_direct_free_coherent(struct device *dev, size_t size, 46 void *vaddr, dma_addr_t dma_handle, 47 unsigned long attrs) 48 { 49 #ifdef NOT_COHERENT_CACHE 50 consistent_free(size, vaddr); 51 #else 52 free_pages((unsigned long)vaddr, get_order(size)); 53 #endif 54 } 55 56 static inline void __dma_sync(unsigned long paddr, 57 size_t size, enum dma_data_direction direction) 58 { 59 switch (direction) { 60 case DMA_TO_DEVICE: 61 case DMA_BIDIRECTIONAL: 62 flush_dcache_range(paddr, paddr + size); 63 break; 64 case DMA_FROM_DEVICE: 65 invalidate_dcache_range(paddr, paddr + size); 66 break; 67 default: 68 BUG(); 69 } 70 } 71 72 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, 73 int nents, enum dma_data_direction direction, 74 unsigned long attrs) 75 { 76 struct scatterlist *sg; 77 int i; 78 79 /* FIXME this part of code is untested */ 80 for_each_sg(sgl, sg, nents, i) { 81 sg->dma_address = sg_phys(sg); 82 83 if (attrs & DMA_ATTR_SKIP_CPU_SYNC) 84 continue; 85 86 __dma_sync(sg_phys(sg), sg->length, direction); 87 } 88 89 return nents; 90 } 91 92 static int dma_direct_dma_supported(struct device *dev, u64 mask) 93 { 94 return 1; 95 } 96 97 static inline dma_addr_t dma_direct_map_page(struct device *dev, 98 struct page *page, 99 unsigned long offset, 100 size_t size, 101 enum dma_data_direction direction, 102 unsigned long attrs) 103 { 104 if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) 105 __dma_sync(page_to_phys(page) + offset, size, direction); 106 return page_to_phys(page) + offset; 107 } 108 109 static inline void dma_direct_unmap_page(struct device *dev, 110 dma_addr_t dma_address, 111 size_t size, 112 enum dma_data_direction direction, 113 unsigned long attrs) 114 { 115 /* There is not necessary to do cache cleanup 116 * 117 * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and 118 * dma_address is physical address 119 */ 120 if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) 121 __dma_sync(dma_address, size, direction); 122 } 123 124 static inline void 125 dma_direct_sync_single_for_cpu(struct device *dev, 126 dma_addr_t dma_handle, size_t size, 127 enum dma_data_direction direction) 128 { 129 /* 130 * It's pointless to flush the cache as the memory segment 131 * is given to the CPU 132 */ 133 134 if (direction == DMA_FROM_DEVICE) 135 __dma_sync(dma_handle, size, direction); 136 } 137 138 static inline void 139 dma_direct_sync_single_for_device(struct device *dev, 140 dma_addr_t dma_handle, size_t size, 141 enum dma_data_direction direction) 142 { 143 /* 144 * It's pointless to invalidate the cache if the device isn't 145 * supposed to write to the relevant region 146 */ 147 148 if (direction == DMA_TO_DEVICE) 149 __dma_sync(dma_handle, size, direction); 150 } 151 152 static inline void 153 dma_direct_sync_sg_for_cpu(struct device *dev, 154 struct scatterlist *sgl, int nents, 155 enum dma_data_direction direction) 156 { 157 struct scatterlist *sg; 158 int i; 159 160 /* FIXME this part of code is untested */ 161 if (direction == DMA_FROM_DEVICE) 162 for_each_sg(sgl, sg, nents, i) 163 __dma_sync(sg->dma_address, sg->length, direction); 164 } 165 166 static inline void 167 dma_direct_sync_sg_for_device(struct device *dev, 168 struct scatterlist *sgl, int nents, 169 enum dma_data_direction direction) 170 { 171 struct scatterlist *sg; 172 int i; 173 174 /* FIXME this part of code is untested */ 175 if (direction == DMA_TO_DEVICE) 176 for_each_sg(sgl, sg, nents, i) 177 __dma_sync(sg->dma_address, sg->length, direction); 178 } 179 180 static 181 int dma_direct_mmap_coherent(struct device *dev, struct vm_area_struct *vma, 182 void *cpu_addr, dma_addr_t handle, size_t size, 183 unsigned long attrs) 184 { 185 #ifdef CONFIG_MMU 186 unsigned long user_count = vma_pages(vma); 187 unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT; 188 unsigned long off = vma->vm_pgoff; 189 unsigned long pfn; 190 191 if (off >= count || user_count > (count - off)) 192 return -ENXIO; 193 194 #ifdef NOT_COHERENT_CACHE 195 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); 196 pfn = consistent_virt_to_pfn(cpu_addr); 197 #else 198 pfn = virt_to_pfn(cpu_addr); 199 #endif 200 return remap_pfn_range(vma, vma->vm_start, pfn + off, 201 vma->vm_end - vma->vm_start, vma->vm_page_prot); 202 #else 203 return -ENXIO; 204 #endif 205 } 206 207 const struct dma_map_ops dma_direct_ops = { 208 .alloc = dma_direct_alloc_coherent, 209 .free = dma_direct_free_coherent, 210 .mmap = dma_direct_mmap_coherent, 211 .map_sg = dma_direct_map_sg, 212 .dma_supported = dma_direct_dma_supported, 213 .map_page = dma_direct_map_page, 214 .unmap_page = dma_direct_unmap_page, 215 .sync_single_for_cpu = dma_direct_sync_single_for_cpu, 216 .sync_single_for_device = dma_direct_sync_single_for_device, 217 .sync_sg_for_cpu = dma_direct_sync_sg_for_cpu, 218 .sync_sg_for_device = dma_direct_sync_sg_for_device, 219 }; 220 EXPORT_SYMBOL(dma_direct_ops); 221 222 /* Number of entries preallocated for DMA-API debugging */ 223 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16) 224 225 static int __init dma_init(void) 226 { 227 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES); 228 229 return 0; 230 } 231 fs_initcall(dma_init); 232