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 #ifdef CONFIG_PCI
  38         prog->kvirt = pci_alloc_consistent(dev, n_bytes, &prog->bus_addr);
  39 #else
  40         prog->kvirt = kmalloc(n_bytes, in_interrupt()? GFP_ATOMIC: GFP_KERNEL);
  41 #endif
  42         if (!prog->kvirt) {
  43                 printk(KERN_ERR
  44                        "dma_prog_region_alloc: pci_alloc_consistent() failed\n");
  45                 dma_prog_region_free(prog);
  46                 return -ENOMEM;
  47         }
  48
  49         prog->dev = dev;
  50
  51         return 0;
  52 }
  53
  54 void dma_prog_region_free(struct dma_prog_region *prog)
  55 {
  56         if (prog->kvirt) {
  57 #ifdef CONFIG_PCI
  58                 pci_free_consistent(prog->dev, prog->n_pages << PAGE_SHIFT,
  59                                     prog->kvirt, prog->bus_addr);
  60 #else
  61                 kfree(prog->kvirt);
  62 #endif
  63         }
  64
  65         prog->kvirt = NULL;
  66         prog->dev = NULL;
  67         prog->n_pages = 0;
  68         prog->bus_addr = 0;
  69 }
  70
  71 /* dma_region */
  72
  73 void dma_region_init(struct dma_region *dma)
  74 {
  75         dma->kvirt = NULL;
  76         dma->dev = NULL;
  77         dma->n_pages = 0;
  78         dma->n_dma_pages = 0;
  79         dma->sglist = NULL;
  80 }
  81
  82 int dma_region_alloc(struct dma_region *dma, unsigned long n_bytes,
  83                      struct pci_dev *dev, int direction)
  84 {
  85         unsigned int i;
  86
  87         /* round up to page size */
  88         n_bytes = PAGE_ALIGN(n_bytes);
  89
  90         dma->n_pages = n_bytes >> PAGE_SHIFT;
  91
  92         dma->kvirt = vmalloc_32(n_bytes);
  93         if (!dma->kvirt) {
  94                 printk(KERN_ERR "dma_region_alloc: vmalloc_32() failed\n");
  95                 goto err;
  96         }
  97
  98         /* Clear the ram out, no junk to the user */
  99         memset(dma->kvirt, 0, n_bytes);
 100
 101         /* allocate scatter/gather list */
 102         dma->sglist = vmalloc(dma->n_pages * sizeof(*dma->sglist));
 103         if (!dma->sglist) {
 104                 printk(KERN_ERR "dma_region_alloc: vmalloc(sglist) failed\n");
 105                 goto err;
 106         }
 107
 108         /* just to be safe - this will become unnecessary once sglist->address goes away */
 109         memset(dma->sglist, 0, dma->n_pages * sizeof(*dma->sglist));
 110
 111         /* fill scatter/gather list with pages */
 112         for (i = 0; i < dma->n_pages; i++) {
 113                 unsigned long va =
 114                     (unsigned long)dma->kvirt + (i << PAGE_SHIFT);
 115
 116                 dma->sglist[i].page = vmalloc_to_page((void *)va);
 117                 dma->sglist[i].length = PAGE_SIZE;
 118         }
 119
 120         /* map sglist to the IOMMU */
 121 #ifdef CONFIG_PCI
 122         dma->n_dma_pages =
 123             pci_map_sg(dev, dma->sglist, dma->n_pages, direction);
 124 #else
 125         dma->n_dma_pages = dma->n_pages;
 126         for (i = 0; i < dma->n_pages; i++) {
 127                 dma->sglist[i].dma_address = virt_to_bus(page_address(dma->sglist[i].page));
 128         }
 129 #endif
 130
 131         if (dma->n_dma_pages == 0) {
 132                 printk(KERN_ERR "dma_region_alloc: pci_map_sg() failed\n");
 133                 goto err;
 134         }
 135
 136         dma->dev = dev;
 137         dma->direction = direction;
 138
 139         return 0;
 140
 141       err:
 142         dma_region_free(dma);
 143         return -ENOMEM;
 144 }
 145
 146 void dma_region_free(struct dma_region *dma)
 147 {
 148         if (dma->n_dma_pages) {
 149 #ifdef CONFIG_PCI
 150                 pci_unmap_sg(dma->dev, dma->sglist, dma->n_pages,
 151                              dma->direction);
 152 #endif
 153                 dma->n_dma_pages = 0;
 154                 dma->dev = NULL;
 155         }
 156
 157         vfree(dma->sglist);
 158         dma->sglist = NULL;
 159
 160         vfree(dma->kvirt);
 161         dma->kvirt = NULL;
 162         dma->n_pages = 0;
 163 }
 164
 165 /* find the scatterlist index and remaining offset corresponding to a
 166    given offset from the beginning of the buffer */
 167 static inline int dma_region_find(struct dma_region *dma, unsigned long offset,
 168                                   unsigned int start, unsigned long *rem)
 169 {
 170         int i;
 171         unsigned long off = offset;
 172
 173         for (i = start; i < dma->n_dma_pages; i++) {
 174                 if (off < sg_dma_len(&dma->sglist[i])) {
 175                         *rem = off;
 176                         break;
 177                 }
 178
 179                 off -= sg_dma_len(&dma->sglist[i]);
 180         }
 181
 182         BUG_ON(i >= dma->n_dma_pages);
 183
 184         return i;
 185 }
 186
 187 dma_addr_t dma_region_offset_to_bus(struct dma_region * dma,
 188                                     unsigned long offset)
 189 {
 190         unsigned long rem = 0;
 191
 192         struct scatterlist *sg =
 193             &dma->sglist[dma_region_find(dma, offset, 0, &rem)];
 194         return sg_dma_address(sg) + rem;
 195 }
 196
 197 void dma_region_sync_for_cpu(struct dma_region *dma, unsigned long offset,
 198                              unsigned long len)
 199 {
 200 #ifdef CONFIG_PCI
 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 #endif
 213 }
 214
 215 void dma_region_sync_for_device(struct dma_region *dma, unsigned long offset,
 216                                 unsigned long len)
 217 {
 218 #ifdef CONFIG_PCI
 219         int first, last;
 220         unsigned long rem = 0;
 221
 222         if (!len)
 223                 len = 1;
 224
 225         first = dma_region_find(dma, offset, 0, &rem);
 226         last = dma_region_find(dma, rem + len - 1, first, &rem);
 227
 228         pci_dma_sync_sg_for_device(dma->dev, &dma->sglist[first],
 229                                    last - first + 1, dma->direction);
 230 #endif
 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 int dma_region_mmap(struct dma_region *dma, struct file *file,
 269                     struct vm_area_struct *vma)
 270 {
 271         unsigned long size;
 272
 273         if (!dma->kvirt)
 274                 return -EINVAL;
 275
 276         /* must be page-aligned */
 277         if (vma->vm_pgoff != 0)
 278                 return -EINVAL;
 279
 280         /* check the length */
 281         size = vma->vm_end - vma->vm_start;
 282         if (size > (dma->n_pages << PAGE_SHIFT))
 283                 return -EINVAL;
 284
 285         vma->vm_ops = &dma_region_vm_ops;
 286         vma->vm_private_data = dma;
 287         vma->vm_file = file;
 288         vma->vm_flags |= VM_RESERVED;
 289
 290         return 0;
 291 }
 292
 293 #else                           /* CONFIG_MMU */
 294
 295 int dma_region_mmap(struct dma_region *dma, struct file *file,
 296                     struct vm_area_struct *vma)
 297 {
 298         return -EINVAL;
 299 }
 300
 301 #endif                          /* CONFIG_MMU */