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