drivers/ieee1394/dma.c

   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/slab.h>
  14 #include <linux/vmalloc.h>
  15 #include <asm/scatterlist.h>
  16
  17 #include "dma.h"
  18
  19 /* dma_prog_region */
  20
  21 void dma_prog_region_init(struct dma_prog_region *prog)
  22 {
  23         prog->kvirt = NULL;
  24         prog->dev = NULL;
  25         prog->n_pages = 0;
  26         prog->bus_addr = 0;
  27 }
  28
  29 int dma_prog_region_alloc(struct dma_prog_region *prog, unsigned long n_bytes,
  30                           struct pci_dev *dev)
  31 {
  32         /* round up to page size */
  33         n_bytes = PAGE_ALIGN(n_bytes);
  34
  35         prog->n_pages = n_bytes >> PAGE_SHIFT;
  36
  37         prog->kvirt = pci_alloc_consistent(dev, n_bytes, &prog->bus_addr);
  38         if (!prog->kvirt) {
  39                 printk(KERN_ERR
  40                        "dma_prog_region_alloc: pci_alloc_consistent() failed\n");
  41                 dma_prog_region_free(prog);
  42                 return -ENOMEM;
  43         }
  44
  45         prog->dev = dev;
  46
  47         return 0;
  48 }
  49
  50 void dma_prog_region_free(struct dma_prog_region *prog)
  51 {
  52         if (prog->kvirt) {
  53                 pci_free_consistent(prog->dev, prog->n_pages << PAGE_SHIFT,
  54                                     prog->kvirt, prog->bus_addr);
  55         }
  56
  57         prog->kvirt = NULL;
  58         prog->dev = NULL;
  59         prog->n_pages = 0;
  60         prog->bus_addr = 0;
  61 }
  62
  63 /* dma_region */
  64
  65 /**
  66  * dma_region_init - clear out all fields but do not allocate anything
  67  */
  68 void dma_region_init(struct dma_region *dma)
  69 {
  70         dma->kvirt = NULL;
  71         dma->dev = NULL;
  72         dma->n_pages = 0;
  73         dma->n_dma_pages = 0;
  74         dma->sglist = NULL;
  75 }
  76
  77 /**
  78  * dma_region_alloc - allocate the buffer and map it to the IOMMU
  79  */
  80 int dma_region_alloc(struct dma_region *dma, unsigned long n_bytes,
  81                      struct pci_dev *dev, int direction)
  82 {
  83         unsigned int i;
  84
  85         /* round up to page size */
  86         n_bytes = PAGE_ALIGN(n_bytes);
  87
  88         dma->n_pages = n_bytes >> PAGE_SHIFT;
  89
  90         dma->kvirt = vmalloc_32(n_bytes);
  91         if (!dma->kvirt) {
  92                 printk(KERN_ERR "dma_region_alloc: vmalloc_32() failed\n");
  93                 goto err;
  94         }
  95
  96         /* Clear the ram out, no junk to the user */
  97         memset(dma->kvirt, 0, n_bytes);
  98
  99         /* allocate scatter/gather list */
 100         dma->sglist = vmalloc(dma->n_pages * sizeof(*dma->sglist));
 101         if (!dma->sglist) {
 102                 printk(KERN_ERR "dma_region_alloc: vmalloc(sglist) failed\n");
 103                 goto err;
 104         }
 105
 106         /* just to be safe - this will become unnecessary once sglist->address goes away */
 107         memset(dma->sglist, 0, dma->n_pages * sizeof(*dma->sglist));
 108
 109         /* fill scatter/gather list with pages */
 110         for (i = 0; i < dma->n_pages; i++) {
 111                 unsigned long va =
 112                     (unsigned long)dma->kvirt + (i << PAGE_SHIFT);
 113
 114                 sg_set_page(&dma->sglist[i], vmalloc_to_page((void *)va));
 115                 dma->sglist[i].length = PAGE_SIZE;
 116         }
 117
 118         /* map sglist to the IOMMU */
 119         dma->n_dma_pages =
 120             pci_map_sg(dev, dma->sglist, dma->n_pages, direction);
 121
 122         if (dma->n_dma_pages == 0) {
 123                 printk(KERN_ERR "dma_region_alloc: pci_map_sg() failed\n");
 124                 goto err;
 125         }
 126
 127         dma->dev = dev;
 128         dma->direction = direction;
 129
 130         return 0;
 131
 132       err:
 133         dma_region_free(dma);
 134         return -ENOMEM;
 135 }
 136
 137 /**
 138  * dma_region_free - unmap and free the buffer
 139  */
 140 void dma_region_free(struct dma_region *dma)
 141 {
 142         if (dma->n_dma_pages) {
 143                 pci_unmap_sg(dma->dev, dma->sglist, dma->n_pages,
 144                              dma->direction);
 145                 dma->n_dma_pages = 0;
 146                 dma->dev = NULL;
 147         }
 148
 149         vfree(dma->sglist);
 150         dma->sglist = NULL;
 151
 152         vfree(dma->kvirt);
 153         dma->kvirt = NULL;
 154         dma->n_pages = 0;
 155 }
 156
 157 /* find the scatterlist index and remaining offset corresponding to a
 158    given offset from the beginning of the buffer */
 159 static inline int dma_region_find(struct dma_region *dma, unsigned long offset,
 160                                   unsigned int start, unsigned long *rem)
 161 {
 162         int i;
 163         unsigned long off = offset;
 164
 165         for (i = start; i < dma->n_dma_pages; i++) {
 166                 if (off < sg_dma_len(&dma->sglist[i])) {
 167                         *rem = off;
 168                         break;
 169                 }
 170
 171                 off -= sg_dma_len(&dma->sglist[i]);
 172         }
 173
 174         BUG_ON(i >= dma->n_dma_pages);
 175
 176         return i;
 177 }
 178
 179 /**
 180  * dma_region_offset_to_bus - get bus address of an offset within a DMA region
 181  *
 182  * Returns the DMA bus address of the byte with the given @offset relative to
 183  * the beginning of the @dma.
 184  */
 185 dma_addr_t dma_region_offset_to_bus(struct dma_region * dma,
 186                                     unsigned long offset)
 187 {
 188         unsigned long rem = 0;
 189
 190         struct scatterlist *sg =
 191             &dma->sglist[dma_region_find(dma, offset, 0, &rem)];
 192         return sg_dma_address(sg) + rem;
 193 }
 194
 195 /**
 196  * dma_region_sync_for_cpu - sync the CPU's view of the buffer
 197  */
 198 void dma_region_sync_for_cpu(struct dma_region *dma, unsigned long offset,
 199                              unsigned long len)
 200 {
 201         int first, last;
 202         unsigned long rem = 0;
 203
 204         if (!len)
 205                 len = 1;
 206
 207         first = dma_region_find(dma, offset, 0, &rem);
 208         last = dma_region_find(dma, rem + len - 1, first, &rem);
 209
 210         pci_dma_sync_sg_for_cpu(dma->dev, &dma->sglist[first], last - first + 1,
 211                                 dma->direction);
 212 }
 213
 214 /**
 215  * dma_region_sync_for_device - sync the IO bus' view of the buffer
 216  */
 217 void dma_region_sync_for_device(struct dma_region *dma, unsigned long offset,
 218                                 unsigned long len)
 219 {
 220         int first, last;
 221         unsigned long rem = 0;
 222
 223         if (!len)
 224                 len = 1;
 225
 226         first = dma_region_find(dma, offset, 0, &rem);
 227         last = dma_region_find(dma, rem + len - 1, first, &rem);
 228
 229         pci_dma_sync_sg_for_device(dma->dev, &dma->sglist[first],
 230                                    last - first + 1, dma->direction);
 231 }
 232
 233 #ifdef CONFIG_MMU
 234
 235 /* nopage() handler for mmap access */
 236
 237 static struct page *dma_region_pagefault(struct vm_area_struct *area,
 238                                          unsigned long address, int *type)
 239 {
 240         unsigned long offset;
 241         unsigned long kernel_virt_addr;
 242         struct page *ret = NOPAGE_SIGBUS;
 243
 244         struct dma_region *dma = (struct dma_region *)area->vm_private_data;
 245
 246         if (!dma->kvirt)
 247                 goto out;
 248
 249         if ((address < (unsigned long)area->vm_start) ||
 250             (address >
 251              (unsigned long)area->vm_start + (dma->n_pages << PAGE_SHIFT)))
 252                 goto out;
 253
 254         if (type)
 255                 *type = VM_FAULT_MINOR;
 256         offset = address - area->vm_start;
 257         kernel_virt_addr = (unsigned long)dma->kvirt + offset;
 258         ret = vmalloc_to_page((void *)kernel_virt_addr);
 259         get_page(ret);
 260       out:
 261         return ret;
 262 }
 263
 264 static struct vm_operations_struct dma_region_vm_ops = {
 265         .nopage = dma_region_pagefault,
 266 };
 267
 268 /**
 269  * dma_region_mmap - map the buffer into a user space process
 270  */
 271 int dma_region_mmap(struct dma_region *dma, struct file *file,
 272                     struct vm_area_struct *vma)
 273 {
 274         unsigned long size;
 275
 276         if (!dma->kvirt)
 277                 return -EINVAL;
 278
 279         /* must be page-aligned */
 280         if (vma->vm_pgoff != 0)
 281                 return -EINVAL;
 282
 283         /* check the length */
 284         size = vma->vm_end - vma->vm_start;
 285         if (size > (dma->n_pages << PAGE_SHIFT))
 286                 return -EINVAL;
 287
 288         vma->vm_ops = &dma_region_vm_ops;
 289         vma->vm_private_data = dma;
 290         vma->vm_file = file;
 291         vma->vm_flags |= VM_RESERVED;
 292
 293         return 0;
 294 }
 295
 296 #else                           /* CONFIG_MMU */
 297
 298 int dma_region_mmap(struct dma_region *dma, struct file *file,
 299                     struct vm_area_struct *vma)
 300 {
 301         return -EINVAL;
 302 }
 303
 304 #endif                          /* CONFIG_MMU */