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 <linux/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         sg_init_table(dma->sglist, dma->n_pages);
 107
 108         /* fill scatter/gather list with pages */
 109         for (i = 0; i < dma->n_pages; i++) {
 110                 unsigned long va =
 111                     (unsigned long)dma->kvirt + (i << PAGE_SHIFT);
 112
 113                 sg_set_page(&dma->sglist[i], vmalloc_to_page((void *)va),
 114                                 PAGE_SIZE, 0);
 115         }
 116
 117         /* map sglist to the IOMMU */
 118         dma->n_dma_pages =
 119             pci_map_sg(dev, dma->sglist, dma->n_pages, direction);
 120
 121         if (dma->n_dma_pages == 0) {
 122                 printk(KERN_ERR "dma_region_alloc: pci_map_sg() failed\n");
 123                 goto err;
 124         }
 125
 126         dma->dev = dev;
 127         dma->direction = direction;
 128
 129         return 0;
 130
 131       err:
 132         dma_region_free(dma);
 133         return -ENOMEM;
 134 }
 135
 136 /**
 137  * dma_region_free - unmap and free the buffer
 138  */
 139 void dma_region_free(struct dma_region *dma)
 140 {
 141         if (dma->n_dma_pages) {
 142                 pci_unmap_sg(dma->dev, dma->sglist, dma->n_pages,
 143                              dma->direction);
 144                 dma->n_dma_pages = 0;
 145                 dma->dev = NULL;
 146         }
 147
 148         vfree(dma->sglist);
 149         dma->sglist = NULL;
 150
 151         vfree(dma->kvirt);
 152         dma->kvirt = NULL;
 153         dma->n_pages = 0;
 154 }
 155
 156 /* find the scatterlist index and remaining offset corresponding to a
 157    given offset from the beginning of the buffer */
 158 static inline int dma_region_find(struct dma_region *dma, unsigned long offset,
 159                                   unsigned int start, unsigned long *rem)
 160 {
 161         int i;
 162         unsigned long off = offset;
 163
 164         for (i = start; i < dma->n_dma_pages; i++) {
 165                 if (off < sg_dma_len(&dma->sglist[i])) {
 166                         *rem = off;
 167                         break;
 168                 }
 169
 170                 off -= sg_dma_len(&dma->sglist[i]);
 171         }
 172
 173         BUG_ON(i >= dma->n_dma_pages);
 174
 175         return i;
 176 }
 177
 178 /**
 179  * dma_region_offset_to_bus - get bus address of an offset within a DMA region
 180  *
 181  * Returns the DMA bus address of the byte with the given @offset relative to
 182  * the beginning of the @dma.
 183  */
 184 dma_addr_t dma_region_offset_to_bus(struct dma_region * dma,
 185                                     unsigned long offset)
 186 {
 187         unsigned long rem = 0;
 188
 189         struct scatterlist *sg =
 190             &dma->sglist[dma_region_find(dma, offset, 0, &rem)];
 191         return sg_dma_address(sg) + rem;
 192 }
 193
 194 /**
 195  * dma_region_sync_for_cpu - sync the CPU's view of the buffer
 196  */
 197 void dma_region_sync_for_cpu(struct dma_region *dma, unsigned long offset,
 198                              unsigned long len)
 199 {
 200         int first, last;
 201         unsigned long rem = 0;
 202
 203         if (!len)
 204                 len = 1;
 205
 206         first = dma_region_find(dma, offset, 0, &rem);
 207         last = dma_region_find(dma, rem + len - 1, first, &rem);
 208
 209         pci_dma_sync_sg_for_cpu(dma->dev, &dma->sglist[first], last - first + 1,
 210                                 dma->direction);
 211 }
 212
 213 /**
 214  * dma_region_sync_for_device - sync the IO bus' view of the buffer
 215  */
 216 void dma_region_sync_for_device(struct dma_region *dma, unsigned long offset,
 217                                 unsigned long len)
 218 {
 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 }
 231
 232 #ifdef CONFIG_MMU
 233
 234 static int dma_region_pagefault(struct vm_area_struct *vma,
 235                                 struct vm_fault *vmf)
 236 {
 237         struct dma_region *dma = (struct dma_region *)vma->vm_private_data;
 238
 239         if (!dma->kvirt)
 240                 return VM_FAULT_SIGBUS;
 241
 242         if (vmf->pgoff >= dma->n_pages)
 243                 return VM_FAULT_SIGBUS;
 244
 245         vmf->page = vmalloc_to_page(dma->kvirt + (vmf->pgoff << PAGE_SHIFT));
 246         get_page(vmf->page);
 247         return 0;
 248 }
 249
 250 static const struct vm_operations_struct dma_region_vm_ops = {
 251         .fault = dma_region_pagefault,
 252 };
 253
 254 /**
 255  * dma_region_mmap - map the buffer into a user space process
 256  */
 257 int dma_region_mmap(struct dma_region *dma, struct file *file,
 258                     struct vm_area_struct *vma)
 259 {
 260         unsigned long size;
 261
 262         if (!dma->kvirt)
 263                 return -EINVAL;
 264
 265         /* must be page-aligned (XXX: comment is wrong, we could allow pgoff) */
 266         if (vma->vm_pgoff != 0)
 267                 return -EINVAL;
 268
 269         /* check the length */
 270         size = vma->vm_end - vma->vm_start;
 271         if (size > (dma->n_pages << PAGE_SHIFT))
 272                 return -EINVAL;
 273
 274         vma->vm_ops = &dma_region_vm_ops;
 275         vma->vm_private_data = dma;
 276         vma->vm_file = file;
 277         vma->vm_flags |= VM_RESERVED | VM_ALWAYSDUMP;
 278
 279         return 0;
 280 }
 281
 282 #else                           /* CONFIG_MMU */
 283
 284 int dma_region_mmap(struct dma_region *dma, struct file *file,
 285                     struct vm_area_struct *vma)
 286 {
 287         return -EINVAL;
 288 }
 289
 290 #endif                          /* CONFIG_MMU */