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/module.h>
  11 #include <linux/vmalloc.h>
  12 #include <linux/slab.h>
  13 #include <linux/mm.h>
  14 #include "dma.h"
  15
  16 /* dma_prog_region */
  17
  18 void dma_prog_region_init(struct dma_prog_region *prog)
  19 {
  20         prog->kvirt = NULL;
  21         prog->dev = NULL;
  22         prog->n_pages = 0;
  23         prog->bus_addr = 0;
  24 }
  25
  26 int dma_prog_region_alloc(struct dma_prog_region *prog, unsigned long n_bytes,
  27                           struct pci_dev *dev)
  28 {
  29         /* round up to page size */
  30         n_bytes = PAGE_ALIGN(n_bytes);
  31
  32         prog->n_pages = n_bytes >> PAGE_SHIFT;
  33
  34         prog->kvirt = pci_alloc_consistent(dev, n_bytes, &prog->bus_addr);
  35         if (!prog->kvirt) {
  36                 printk(KERN_ERR
  37                        "dma_prog_region_alloc: pci_alloc_consistent() failed\n");
  38                 dma_prog_region_free(prog);
  39                 return -ENOMEM;
  40         }
  41
  42         prog->dev = dev;
  43
  44         return 0;
  45 }
  46
  47 void dma_prog_region_free(struct dma_prog_region *prog)
  48 {
  49         if (prog->kvirt) {
  50                 pci_free_consistent(prog->dev, prog->n_pages << PAGE_SHIFT,
  51                                     prog->kvirt, prog->bus_addr);
  52         }
  53
  54         prog->kvirt = NULL;
  55         prog->dev = NULL;
  56         prog->n_pages = 0;
  57         prog->bus_addr = 0;
  58 }
  59
  60 /* dma_region */
  61
  62 void dma_region_init(struct dma_region *dma)
  63 {
  64         dma->kvirt = NULL;
  65         dma->dev = NULL;
  66         dma->n_pages = 0;
  67         dma->n_dma_pages = 0;
  68         dma->sglist = NULL;
  69 }
  70
  71 int dma_region_alloc(struct dma_region *dma, unsigned long n_bytes,
  72                      struct pci_dev *dev, int direction)
  73 {
  74         unsigned int i;
  75
  76         /* round up to page size */
  77         n_bytes = PAGE_ALIGN(n_bytes);
  78
  79         dma->n_pages = n_bytes >> PAGE_SHIFT;
  80
  81         dma->kvirt = vmalloc_32(n_bytes);
  82         if (!dma->kvirt) {
  83                 printk(KERN_ERR "dma_region_alloc: vmalloc_32() failed\n");
  84                 goto err;
  85         }
  86
  87         /* Clear the ram out, no junk to the user */
  88         memset(dma->kvirt, 0, n_bytes);
  89
  90         /* allocate scatter/gather list */
  91         dma->sglist = vmalloc(dma->n_pages * sizeof(*dma->sglist));
  92         if (!dma->sglist) {
  93                 printk(KERN_ERR "dma_region_alloc: vmalloc(sglist) failed\n");
  94                 goto err;
  95         }
  96
  97         /* just to be safe - this will become unnecessary once sglist->address goes away */
  98         memset(dma->sglist, 0, dma->n_pages * sizeof(*dma->sglist));
  99
 100         /* fill scatter/gather list with pages */
 101         for (i = 0; i < dma->n_pages; i++) {
 102                 unsigned long va =
 103                     (unsigned long)dma->kvirt + (i << PAGE_SHIFT);
 104
 105                 dma->sglist[i].page = vmalloc_to_page((void *)va);
 106                 dma->sglist[i].length = PAGE_SIZE;
 107         }
 108
 109         /* map sglist to the IOMMU */
 110         dma->n_dma_pages =
 111             pci_map_sg(dev, dma->sglist, dma->n_pages, direction);
 112
 113         if (dma->n_dma_pages == 0) {
 114                 printk(KERN_ERR "dma_region_alloc: pci_map_sg() failed\n");
 115                 goto err;
 116         }
 117
 118         dma->dev = dev;
 119         dma->direction = direction;
 120
 121         return 0;
 122
 123       err:
 124         dma_region_free(dma);
 125         return -ENOMEM;
 126 }
 127
 128 void dma_region_free(struct dma_region *dma)
 129 {
 130         if (dma->n_dma_pages) {
 131                 pci_unmap_sg(dma->dev, dma->sglist, dma->n_pages,
 132                              dma->direction);
 133                 dma->n_dma_pages = 0;
 134                 dma->dev = NULL;
 135         }
 136
 137         vfree(dma->sglist);
 138         dma->sglist = NULL;
 139
 140         vfree(dma->kvirt);
 141         dma->kvirt = NULL;
 142         dma->n_pages = 0;
 143 }
 144
 145 /* find the scatterlist index and remaining offset corresponding to a
 146    given offset from the beginning of the buffer */
 147 static inline int dma_region_find(struct dma_region *dma, unsigned long offset,
 148                                   unsigned int start, unsigned long *rem)
 149 {
 150         int i;
 151         unsigned long off = offset;
 152
 153         for (i = start; i < dma->n_dma_pages; i++) {
 154                 if (off < sg_dma_len(&dma->sglist[i])) {
 155                         *rem = off;
 156                         break;
 157                 }
 158
 159                 off -= sg_dma_len(&dma->sglist[i]);
 160         }
 161
 162         BUG_ON(i >= dma->n_dma_pages);
 163
 164         return i;
 165 }
 166
 167 dma_addr_t dma_region_offset_to_bus(struct dma_region * dma,
 168                                     unsigned long offset)
 169 {
 170         unsigned long rem = 0;
 171
 172         struct scatterlist *sg =
 173             &dma->sglist[dma_region_find(dma, offset, 0, &rem)];
 174         return sg_dma_address(sg) + rem;
 175 }
 176
 177 void dma_region_sync_for_cpu(struct dma_region *dma, unsigned long offset,
 178                              unsigned long len)
 179 {
 180         int first, last;
 181         unsigned long rem = 0;
 182
 183         if (!len)
 184                 len = 1;
 185
 186         first = dma_region_find(dma, offset, 0, &rem);
 187         last = dma_region_find(dma, rem + len - 1, first, &rem);
 188
 189         pci_dma_sync_sg_for_cpu(dma->dev, &dma->sglist[first], last - first + 1,
 190                                 dma->direction);
 191 }
 192
 193 void dma_region_sync_for_device(struct dma_region *dma, unsigned long offset,
 194                                 unsigned long len)
 195 {
 196         int first, last;
 197         unsigned long rem = 0;
 198
 199         if (!len)
 200                 len = 1;
 201
 202         first = dma_region_find(dma, offset, 0, &rem);
 203         last = dma_region_find(dma, rem + len - 1, first, &rem);
 204
 205         pci_dma_sync_sg_for_device(dma->dev, &dma->sglist[first],
 206                                    last - first + 1, dma->direction);
 207 }
 208
 209 #ifdef CONFIG_MMU
 210
 211 /* nopage() handler for mmap access */
 212
 213 static struct page *dma_region_pagefault(struct vm_area_struct *area,
 214                                          unsigned long address, int *type)
 215 {
 216         unsigned long offset;
 217         unsigned long kernel_virt_addr;
 218         struct page *ret = NOPAGE_SIGBUS;
 219
 220         struct dma_region *dma = (struct dma_region *)area->vm_private_data;
 221
 222         if (!dma->kvirt)
 223                 goto out;
 224
 225         if ((address < (unsigned long)area->vm_start) ||
 226             (address >
 227              (unsigned long)area->vm_start + (dma->n_pages << PAGE_SHIFT)))
 228                 goto out;
 229
 230         if (type)
 231                 *type = VM_FAULT_MINOR;
 232         offset = address - area->vm_start;
 233         kernel_virt_addr = (unsigned long)dma->kvirt + offset;
 234         ret = vmalloc_to_page((void *)kernel_virt_addr);
 235         get_page(ret);
 236       out:
 237         return ret;
 238 }
 239
 240 static struct vm_operations_struct dma_region_vm_ops = {
 241         .nopage = dma_region_pagefault,
 242 };
 243
 244 int dma_region_mmap(struct dma_region *dma, struct file *file,
 245                     struct vm_area_struct *vma)
 246 {
 247         unsigned long size;
 248
 249         if (!dma->kvirt)
 250                 return -EINVAL;
 251
 252         /* must be page-aligned */
 253         if (vma->vm_pgoff != 0)
 254                 return -EINVAL;
 255
 256         /* check the length */
 257         size = vma->vm_end - vma->vm_start;
 258         if (size > (dma->n_pages << PAGE_SHIFT))
 259                 return -EINVAL;
 260
 261         vma->vm_ops = &dma_region_vm_ops;
 262         vma->vm_private_data = dma;
 263         vma->vm_file = file;
 264         vma->vm_flags |= VM_RESERVED;
 265
 266         return 0;
 267 }
 268
 269 #else                           /* CONFIG_MMU */
 270
 271 int dma_region_mmap(struct dma_region *dma, struct file *file,
 272                     struct vm_area_struct *vma)
 273 {
 274         return -EINVAL;
 275 }
 276
 277 #endif                          /* CONFIG_MMU */