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
  16 void *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 || 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
  33 void 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 }