1/* 2 * DMA region bookkeeping routines 3 * 4 * Copyright (C) 2002 Maas Digital LLC 5 * 6 * This code is licensed under the GPL. See the file COPYING in the root 7 * directory of the kernel sources for details. 8 */ 9 10#include <linux/mm.h> 11#include <linux/module.h> 12#include <linux/pci.h> 13#include <linux/vmalloc.h> 14#include <linux/scatterlist.h> 15 16#include "dma.h" 17 18/* dma_prog_region */ 19 20void dma_prog_region_init(struct dma_prog_region *prog) 21{ 22 prog->kvirt = NULL; 23 prog->dev = NULL; 24 prog->n_pages = 0; 25 prog->bus_addr = 0; 26} 27 28int dma_prog_region_alloc(struct dma_prog_region *prog, unsigned long n_bytes, 29 struct pci_dev *dev) 30{ 31 /* round up to page size */ 32 n_bytes = PAGE_ALIGN(n_bytes); 33 34 prog->n_pages = n_bytes >> PAGE_SHIFT; 35 36 prog->kvirt = pci_alloc_consistent(dev, n_bytes, &prog->bus_addr); 37 if (!prog->kvirt) { 38 printk(KERN_ERR 39 "dma_prog_region_alloc: pci_alloc_consistent() failed\n"); 40 dma_prog_region_free(prog); 41 return -ENOMEM; 42 } 43 44 prog->dev = dev; 45 46 return 0; 47} 48 49void dma_prog_region_free(struct dma_prog_region *prog) 50{ 51 if (prog->kvirt) { 52 pci_free_consistent(prog->dev, prog->n_pages << PAGE_SHIFT, 53 prog->kvirt, prog->bus_addr); 54 } 55 56 prog->kvirt = NULL; 57 prog->dev = NULL; 58 prog->n_pages = 0; 59 prog->bus_addr = 0; 60} 61 62/* dma_region */ 63 64/** 65 * dma_region_init - clear out all fields but do not allocate anything 66 */ 67void dma_region_init(struct dma_region *dma) 68{ 69 dma->kvirt = NULL; 70 dma->dev = NULL; 71 dma->n_pages = 0; 72 dma->n_dma_pages = 0; 73 dma->sglist = NULL; 74} 75 76/** 77 * dma_region_alloc - allocate the buffer and map it to the IOMMU 78 */ 79int dma_region_alloc(struct dma_region *dma, unsigned long n_bytes, 80 struct pci_dev *dev, int direction) 81{ 82 unsigned int i; 83 84 /* round up to page size */ 85 n_bytes = PAGE_ALIGN(n_bytes); 86 87 dma->n_pages = n_bytes >> PAGE_SHIFT; 88 89 dma->kvirt = vmalloc_32(n_bytes); 90 if (!dma->kvirt) { 91 printk(KERN_ERR "dma_region_alloc: vmalloc_32() failed\n"); 92 goto err; 93 } 94 95 /* Clear the ram out, no junk to the user */ 96 memset(dma->kvirt, 0, n_bytes); 97 98 /* allocate scatter/gather list */ 99 dma->sglist = vmalloc(dma->n_pages * sizeof(*dma->sglist)); 100 if (!dma->sglist) { 101 printk(KERN_ERR "dma_region_alloc: vmalloc(sglist) failed\n"); 102 goto err; 103 } 104 105 sg_init_table(dma->sglist, dma->n_pages); 106 107 /* fill scatter/gather list with pages */ 108 for (i = 0; i < dma->n_pages; i++) { 109 unsigned long va = 110 (unsigned long)dma->kvirt + (i << PAGE_SHIFT); 111 112 sg_set_page(&dma->sglist[i], vmalloc_to_page((void *)va), 113 PAGE_SIZE, 0); 114 } 115 116 /* map sglist to the IOMMU */ 117 dma->n_dma_pages = 118 pci_map_sg(dev, dma->sglist, dma->n_pages, direction); 119 120 if (dma->n_dma_pages == 0) { 121 printk(KERN_ERR "dma_region_alloc: pci_map_sg() failed\n"); 122 goto err; 123 } 124 125 dma->dev = dev; 126 dma->direction = direction; 127 128 return 0; 129 130 err: 131 dma_region_free(dma); 132 return -ENOMEM; 133} 134 135/** 136 * dma_region_free - unmap and free the buffer 137 */ 138void dma_region_free(struct dma_region *dma) 139{ 140 if (dma->n_dma_pages) { 141 pci_unmap_sg(dma->dev, dma->sglist, dma->n_pages, 142 dma->direction); 143 dma->n_dma_pages = 0; 144 dma->dev = NULL; 145 } 146 147 vfree(dma->sglist); 148 dma->sglist = NULL; 149 150 vfree(dma->kvirt); 151 dma->kvirt = NULL; 152 dma->n_pages = 0; 153} 154 155/* find the scatterlist index and remaining offset corresponding to a 156 given offset from the beginning of the buffer */ 157static inline int dma_region_find(struct dma_region *dma, unsigned long offset, 158 unsigned int start, unsigned long *rem) 159{ 160 int i; 161 unsigned long off = offset; 162 163 for (i = start; i < dma->n_dma_pages; i++) { 164 if (off < sg_dma_len(&dma->sglist[i])) { 165 *rem = off; 166 break; 167 } 168 169 off -= sg_dma_len(&dma->sglist[i]); 170 } 171 172 BUG_ON(i >= dma->n_dma_pages); 173 174 return i; 175} 176 177/** 178 * dma_region_offset_to_bus - get bus address of an offset within a DMA region 179 * 180 * Returns the DMA bus address of the byte with the given @offset relative to 181 * the beginning of the @dma. 182 */ 183dma_addr_t dma_region_offset_to_bus(struct dma_region * dma, 184 unsigned long offset) 185{ 186 unsigned long rem = 0; 187 188 struct scatterlist *sg = 189 &dma->sglist[dma_region_find(dma, offset, 0, &rem)]; 190 return sg_dma_address(sg) + rem; 191} 192 193/** 194 * dma_region_sync_for_cpu - sync the CPU's view of the buffer 195 */ 196void dma_region_sync_for_cpu(struct dma_region *dma, unsigned long offset, 197 unsigned long len) 198{ 199 int first, last; 200 unsigned long rem = 0; 201 202 if (!len) 203 len = 1; 204 205 first = dma_region_find(dma, offset, 0, &rem); 206 last = dma_region_find(dma, rem + len - 1, first, &rem); 207 208 pci_dma_sync_sg_for_cpu(dma->dev, &dma->sglist[first], last - first + 1, 209 dma->direction); 210} 211 212/** 213 * dma_region_sync_for_device - sync the IO bus' view of the buffer 214 */ 215void dma_region_sync_for_device(struct dma_region *dma, unsigned long offset, 216 unsigned long len) 217{ 218 int first, last; 219 unsigned long rem = 0; 220 221 if (!len) 222 len = 1; 223 224 first = dma_region_find(dma, offset, 0, &rem); 225 last = dma_region_find(dma, rem + len - 1, first, &rem); 226 227 pci_dma_sync_sg_for_device(dma->dev, &dma->sglist[first], 228 last - first + 1, dma->direction); 229} 230 231#ifdef CONFIG_MMU 232 233static int dma_region_pagefault(struct vm_area_struct *vma, 234 struct vm_fault *vmf) 235{ 236 struct dma_region *dma = (struct dma_region *)vma->vm_private_data; 237 238 if (!dma->kvirt) 239 return VM_FAULT_SIGBUS; 240 241 if (vmf->pgoff >= dma->n_pages) 242 return VM_FAULT_SIGBUS; 243 244 vmf->page = vmalloc_to_page(dma->kvirt + (vmf->pgoff << PAGE_SHIFT)); 245 get_page(vmf->page); 246 return 0; 247} 248 249static const struct vm_operations_struct dma_region_vm_ops = { 250 .fault = dma_region_pagefault, 251}; 252 253/** 254 * dma_region_mmap - map the buffer into a user space process 255 */ 256int dma_region_mmap(struct dma_region *dma, struct file *file, 257 struct vm_area_struct *vma) 258{ 259 unsigned long size; 260 261 if (!dma->kvirt) 262 return -EINVAL; 263 264 if (vma->vm_pgoff != 0) 265 return -EINVAL; 266 267 /* check the length */ 268 size = vma->vm_end - vma->vm_start; 269 if (size > (dma->n_pages << PAGE_SHIFT)) 270 return -EINVAL; 271 272 vma->vm_ops = &dma_region_vm_ops; 273 vma->vm_private_data = dma; 274 vma->vm_file = file; 275 vma->vm_flags |= VM_RESERVED | VM_ALWAYSDUMP; 276 277 return 0; 278} 279 280#else /* CONFIG_MMU */ 281 282int dma_region_mmap(struct dma_region *dma, struct file *file, 283 struct vm_area_struct *vma) 284{ 285 return -EINVAL; 286} 287 288#endif /* CONFIG_MMU */ 289