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 void dma_region_init(struct dma_region *dma)
  66 {
  67         dma->kvirt = NULL;
  68         dma->dev = NULL;
  69         dma->n_pages = 0;
  70         dma->n_dma_pages = 0;
  71         dma->sglist = NULL;
  72 }
  73
  74 int dma_region_alloc(struct dma_region *dma, unsigned long n_bytes,
  75                      struct pci_dev *dev, int direction)
  76 {
  77         unsigned int i;
  78
  79         /* round up to page size */
  80         n_bytes = PAGE_ALIGN(n_bytes);
  81
  82         dma->n_pages = n_bytes >> PAGE_SHIFT;
  83
  84         dma->kvirt = vmalloc_32(n_bytes);
  85         if (!dma->kvirt) {
  86                 printk(KERN_ERR "dma_region_alloc: vmalloc_32() failed\n");
  87                 goto err;
  88         }
  89
  90         /* Clear the ram out, no junk to the user */
  91         memset(dma->kvirt, 0, n_bytes);
  92
  93         /* allocate scatter/gather list */
  94         dma->sglist = vmalloc(dma->n_pages * sizeof(*dma->sglist));
  95         if (!dma->sglist) {
  96                 printk(KERN_ERR "dma_region_alloc: vmalloc(sglist) failed\n");
  97                 goto err;
  98         }
  99
 100         /* just to be safe - this will become unnecessary once sglist->address goes away */
 101         memset(dma->sglist, 0, dma->n_pages * sizeof(*dma->sglist));
 102
 103         /* fill scatter/gather list with pages */
 104         for (i = 0; i < dma->n_pages; i++) {
 105                 unsigned long va =
 106                     (unsigned long)dma->kvirt + (i << PAGE_SHIFT);
 107
 108                 dma->sglist[i].page = vmalloc_to_page((void *)va);
 109                 dma->sglist[i].length = PAGE_SIZE;
 110         }
 111
 112         /* map sglist to the IOMMU */
 113         dma->n_dma_pages =
 114             pci_map_sg(dev, dma->sglist, dma->n_pages, direction);
 115
 116         if (dma->n_dma_pages == 0) {
 117                 printk(KERN_ERR "dma_region_alloc: pci_map_sg() failed\n");
 118                 goto err;
 119         }
 120
 121         dma->dev = dev;
 122         dma->direction = direction;
 123
 124         return 0;
 125
 126       err:
 127         dma_region_free(dma);
 128         return -ENOMEM;
 129 }
 130
 131 void dma_region_free(struct dma_region *dma)
 132 {
 133         if (dma->n_dma_pages) {
 134                 pci_unmap_sg(dma->dev, dma->sglist, dma->n_pages,
 135                              dma->direction);
 136                 dma->n_dma_pages = 0;
 137                 dma->dev = NULL;
 138         }
 139
 140         vfree(dma->sglist);
 141         dma->sglist = NULL;
 142
 143         vfree(dma->kvirt);
 144         dma->kvirt = NULL;
 145         dma->n_pages = 0;
 146 }
 147
 148 /* find the scatterlist index and remaining offset corresponding to a
 149    given offset from the beginning of the buffer */
 150 static inline int dma_region_find(struct dma_region *dma, unsigned long offset,
 151                                   unsigned int start, unsigned long *rem)
 152 {
 153         int i;
 154         unsigned long off = offset;
 155
 156         for (i = start; i < dma->n_dma_pages; i++) {
 157                 if (off < sg_dma_len(&dma->sglist[i])) {
 158                         *rem = off;
 159                         break;
 160                 }
 161
 162                 off -= sg_dma_len(&dma->sglist[i]);
 163         }
 164
 165         BUG_ON(i >= dma->n_dma_pages);
 166
 167         return i;
 168 }
 169
 170 dma_addr_t dma_region_offset_to_bus(struct dma_region * dma,
 171                                     unsigned long offset)
 172 {
 173         unsigned long rem = 0;
 174
 175         struct scatterlist *sg =
 176             &dma->sglist[dma_region_find(dma, offset, 0, &rem)];
 177         return sg_dma_address(sg) + rem;
 178 }
 179
 180 void dma_region_sync_for_cpu(struct dma_region *dma, unsigned long offset,
 181                              unsigned long len)
 182 {
 183         int first, last;
 184         unsigned long rem = 0;
 185
 186         if (!len)
 187                 len = 1;
 188
 189         first = dma_region_find(dma, offset, 0, &rem);
 190         last = dma_region_find(dma, rem + len - 1, first, &rem);
 191
 192         pci_dma_sync_sg_for_cpu(dma->dev, &dma->sglist[first], last - first + 1,
 193                                 dma->direction);
 194 }
 195
 196 void dma_region_sync_for_device(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_device(dma->dev, &dma->sglist[first],
 209                                    last - first + 1, dma->direction);
 210 }
 211
 212 #ifdef CONFIG_MMU
 213
 214 /* nopage() handler for mmap access */
 215
 216 static struct page *dma_region_pagefault(struct vm_area_struct *area,
 217                                          unsigned long address, int *type)
 218 {
 219         unsigned long offset;
 220         unsigned long kernel_virt_addr;
 221         struct page *ret = NOPAGE_SIGBUS;
 222
 223         struct dma_region *dma = (struct dma_region *)area->vm_private_data;
 224
 225         if (!dma->kvirt)
 226                 goto out;
 227
 228         if ((address < (unsigned long)area->vm_start) ||
 229             (address >
 230              (unsigned long)area->vm_start + (dma->n_pages << PAGE_SHIFT)))
 231                 goto out;
 232
 233         if (type)
 234                 *type = VM_FAULT_MINOR;
 235         offset = address - area->vm_start;
 236         kernel_virt_addr = (unsigned long)dma->kvirt + offset;
 237         ret = vmalloc_to_page((void *)kernel_virt_addr);
 238         get_page(ret);
 239       out:
 240         return ret;
 241 }
 242
 243 static struct vm_operations_struct dma_region_vm_ops = {
 244         .nopage = dma_region_pagefault,
 245 };
 246
 247 int dma_region_mmap(struct dma_region *dma, struct file *file,
 248                     struct vm_area_struct *vma)
 249 {
 250         unsigned long size;
 251
 252         if (!dma->kvirt)
 253                 return -EINVAL;
 254
 255         /* must be page-aligned */
 256         if (vma->vm_pgoff != 0)
 257                 return -EINVAL;
 258
 259         /* check the length */
 260         size = vma->vm_end - vma->vm_start;
 261         if (size > (dma->n_pages << PAGE_SHIFT))
 262                 return -EINVAL;
 263
 264         vma->vm_ops = &dma_region_vm_ops;
 265         vma->vm_private_data = dma;
 266         vma->vm_file = file;
 267         vma->vm_flags |= VM_RESERVED;
 268
 269         return 0;
 270 }
 271
 272 #else                           /* CONFIG_MMU */
 273
 274 int dma_region_mmap(struct dma_region *dma, struct file *file,
 275                     struct vm_area_struct *vma)
 276 {
 277         return -EINVAL;
 278 }
 279
 280 #endif                          /* CONFIG_MMU */