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 #ifdef CONFIG_PCI
  34         prog->kvirt = pci_alloc_consistent(dev, n_bytes, &prog->bus_addr);
  35 #else
  36         prog->kvirt = kmalloc(n_bytes, in_interrupt()? GFP_ATOMIC: GFP_KERNEL);
  37 #endif
  38         if (!prog->kvirt) {
  39                 printk(KERN_ERR "dma_prog_region_alloc: pci_alloc_consistent() failed\n");
  40                 dma_prog_region_free(prog);
  41                 return -ENOMEM;
  42         }
  43
  44         prog->dev = dev;
  45
  46         return 0;
  47 }
  48
  49 void dma_prog_region_free(struct dma_prog_region *prog)
  50 {
  51         if (prog->kvirt) {
  52 #ifdef CONFIG_PCI
  53                 pci_free_consistent(prog->dev, prog->n_pages << PAGE_SHIFT, prog->kvirt, prog->bus_addr);
  54 #else
  55                 kfree(prog->kvirt);
  56 #endif
  57         }
  58
  59         prog->kvirt = NULL;
  60         prog->dev = NULL;
  61         prog->n_pages = 0;
  62         prog->bus_addr = 0;
  63 }
  64
  65 /* dma_region */
  66
  67 void dma_region_init(struct dma_region *dma)
  68 {
  69         dma->kvirt = NULL;
  70         dma->dev = NULL;
  71         dma->n_pages = 0;
  72         dma->n_dma_pages = 0;
  73         dma->sglist = NULL;
  74 }
  75
  76 int dma_region_alloc(struct dma_region *dma, unsigned long n_bytes, struct pci_dev *dev, int direction)
  77 {
  78         unsigned int i;
  79
  80         /* round up to page size */
  81         n_bytes = PAGE_ALIGN(n_bytes);
  82
  83         dma->n_pages = n_bytes >> PAGE_SHIFT;
  84
  85         dma->kvirt = vmalloc_32(n_bytes);
  86         if (!dma->kvirt) {
  87                 printk(KERN_ERR "dma_region_alloc: vmalloc_32() failed\n");
  88                 goto err;
  89         }
  90
  91         /* Clear the ram out, no junk to the user */
  92         memset(dma->kvirt, 0, n_bytes);
  93
  94         /* allocate scatter/gather list */
  95         dma->sglist = vmalloc(dma->n_pages * sizeof(*dma->sglist));
  96         if (!dma->sglist) {
  97                 printk(KERN_ERR "dma_region_alloc: vmalloc(sglist) failed\n");
  98                 goto err;
  99         }
 100
 101         /* just to be safe - this will become unnecessary once sglist->address goes away */
 102         memset(dma->sglist, 0, dma->n_pages * sizeof(*dma->sglist));
 103
 104         /* fill scatter/gather list with pages */
 105         for (i = 0; i < dma->n_pages; i++) {
 106                 unsigned long va = (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 #ifdef CONFIG_PCI
 114         dma->n_dma_pages = pci_map_sg(dev, dma->sglist, dma->n_pages, direction);
 115 #else
 116         dma->n_dma_pages = dma->n_pages;
 117         for (i = 0; i < dma->n_pages; i++) {
 118                 dma->sglist[i].dma_address = virt_to_bus(page_address(dma->sglist[i].page));
 119         }
 120 #endif
 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 void dma_region_free(struct dma_region *dma)
 137 {
 138         if (dma->n_dma_pages) {
 139 #ifdef CONFIG_PCI
 140                 pci_unmap_sg(dma->dev, dma->sglist, dma->n_pages, dma->direction);
 141 #endif
 142                 dma->n_dma_pages = 0;
 143                 dma->dev = NULL;
 144         }
 145
 146         if (dma->sglist) {
 147                 vfree(dma->sglist);
 148                 dma->sglist = NULL;
 149         }
 150
 151         if (dma->kvirt) {
 152                 vfree(dma->kvirt);
 153                 dma->kvirt = NULL;
 154                 dma->n_pages = 0;
 155         }
 156 }
 157
 158 /* find the scatterlist index and remaining offset corresponding to a
 159    given offset from the beginning of the buffer */
 160 static inline int dma_region_find(struct dma_region *dma, unsigned long offset, unsigned long *rem)
 161 {
 162         int i;
 163         unsigned long off = offset;
 164
 165         for (i = 0; i < dma->n_dma_pages; i++) {
 166                 if (off < sg_dma_len(&dma->sglist[i])) {
 167                         *rem = off;
 168                         break;
 169                 }
 170
 171                 off -= sg_dma_len(&dma->sglist[i]);
 172         }
 173
 174         BUG_ON(i >= dma->n_dma_pages);
 175
 176         return i;
 177 }
 178
 179 dma_addr_t dma_region_offset_to_bus(struct dma_region *dma, unsigned long offset)
 180 {
 181         unsigned long rem;
 182
 183         struct scatterlist *sg = &dma->sglist[dma_region_find(dma, offset, &rem)];
 184         return sg_dma_address(sg) + rem;
 185 }
 186
 187 void dma_region_sync_for_cpu(struct dma_region *dma, unsigned long offset, unsigned long len)
 188 {
 189 #ifdef CONFIG_PCI
 190         int first, last;
 191         unsigned long rem;
 192
 193         if (!len)
 194                 len = 1;
 195
 196         first = dma_region_find(dma, offset, &rem);
 197         last = dma_region_find(dma, offset + len - 1, &rem);
 198
 199         pci_dma_sync_sg_for_cpu(dma->dev, &dma->sglist[first], last - first + 1, dma->direction);
 200 #endif
 201 }
 202
 203 void dma_region_sync_for_device(struct dma_region *dma, unsigned long offset, unsigned long len)
 204 {
 205 #ifdef CONFIG_PCI
 206         int first, last;
 207         unsigned long rem;
 208
 209         if (!len)
 210                 len = 1;
 211
 212         first = dma_region_find(dma, offset, &rem);
 213         last = dma_region_find(dma, offset + len - 1, &rem);
 214
 215         pci_dma_sync_sg_for_device(dma->dev, &dma->sglist[first], last - first + 1, dma->direction);
 216 #endif
 217 }
 218
 219 #ifdef CONFIG_MMU
 220
 221 /* nopage() handler for mmap access */
 222
 223 static struct page*
 224 dma_region_pagefault(struct vm_area_struct *area, unsigned long address, int *type)
 225 {
 226         unsigned long offset;
 227         unsigned long kernel_virt_addr;
 228         struct page *ret = NOPAGE_SIGBUS;
 229
 230         struct dma_region *dma = (struct dma_region*) area->vm_private_data;
 231
 232         if (!dma->kvirt)
 233                 goto out;
 234
 235         if ( (address < (unsigned long) area->vm_start) ||
 236             (address > (unsigned long) area->vm_start + (dma->n_pages << PAGE_SHIFT)) )
 237                 goto out;
 238
 239         if (type)
 240                 *type = VM_FAULT_MINOR;
 241         offset = address - area->vm_start;
 242         kernel_virt_addr = (unsigned long) dma->kvirt + offset;
 243         ret = vmalloc_to_page((void*) kernel_virt_addr);
 244         get_page(ret);
 245 out:
 246         return ret;
 247 }
 248
 249 static struct vm_operations_struct dma_region_vm_ops = {
 250         .nopage = dma_region_pagefault,
 251 };
 252
 253 int dma_region_mmap(struct dma_region *dma, struct file *file, struct vm_area_struct *vma)
 254 {
 255         unsigned long size;
 256
 257         if (!dma->kvirt)
 258                 return -EINVAL;
 259
 260         /* must be page-aligned */
 261         if (vma->vm_pgoff != 0)
 262                 return -EINVAL;
 263
 264         /* check the length */
 265         size = vma->vm_end - vma->vm_start;
 266         if (size > (dma->n_pages << PAGE_SHIFT))
 267                 return -EINVAL;
 268
 269         vma->vm_ops = &dma_region_vm_ops;
 270         vma->vm_private_data = dma;
 271         vma->vm_file = file;
 272         vma->vm_flags |= VM_RESERVED;
 273
 274         return 0;
 275 }
 276
 277 #else /* CONFIG_MMU */
 278
 279 int dma_region_mmap(struct dma_region *dma, struct file *file, struct vm_area_struct *vma)
 280 {
 281         return -EINVAL;
 282 }
 283
 284 #endif /* CONFIG_MMU */