LXR linux-old/arch/i386/kernel/pci-dma.c

   1/*
   2 * Dynamic DMA mapping support.
   3 *
   4 * On i386 there is no hardware dynamic DMA address translation,
   5 * so consistent alloc/free are merely page allocation/freeing.
   6 * The rest of the dynamic DMA mapping interface is implemented
   7 * in asm/pci.h.
   8 */
   9
  10#include <linux/types.h>
  11#include <linux/mm.h>
  12#include <linux/string.h>
  13#include <linux/pci.h>
  14#include <asm/io.h>
  15
  16void *pci_alloc_consistent(struct pci_dev *hwdev, size_t size,
  17                           dma_addr_t *dma_handle)
  18{
  19        void *ret;
  20        int gfp = GFP_ATOMIC;
  21
  22        if (hwdev == NULL || ((u32)hwdev->dma_mask < 0xffffffff))
  23                gfp |= GFP_DMA;
  24        ret = (void *)__get_free_pages(gfp, get_order(size));
  25
  26        if (ret != NULL) {
  27                memset(ret, 0, size);
  28                *dma_handle = virt_to_bus(ret);
  29        }
  30        return ret;
  31}
  32
  33void pci_free_consistent(struct pci_dev *hwdev, size_t size,
  34                         void *vaddr, dma_addr_t dma_handle)
  35{
  36        free_pages((unsigned long)vaddr, get_order(size));
  37}
  38