pci-dma.c 1.2 KB

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  1. /*
  2. * Copyright (C) 2001 David J. Mckay (david.mckay@st.com)
  3. * Copyright (C) 2003 Paul Mundt (lethal@linux-sh.org)
  4. *
  5. * May be copied or modified under the terms of the GNU General Public
  6. * License. See linux/COPYING for more information.
  7. *
  8. * Dynamic DMA mapping support.
  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. void *consistent_alloc(struct pci_dev *hwdev, size_t size,
  16. dma_addr_t *dma_handle)
  17. {
  18. void *ret;
  19. int gfp = GFP_ATOMIC;
  20. void *vp;
  21. if (hwdev == NULL || hwdev->dma_mask != 0xffffffff)
  22. gfp |= GFP_DMA;
  23. ret = (void *)__get_free_pages(gfp, get_order(size));
  24. /* now call our friend ioremap_nocache to give us an uncached area */
  25. vp = ioremap_nocache(virt_to_phys(ret), size);
  26. if (vp != NULL) {
  27. memset(vp, 0, size);
  28. *dma_handle = virt_to_bus(ret);
  29. dma_cache_wback_inv((unsigned long)ret, size);
  30. }
  31. return vp;
  32. }
  33. void consistent_free(struct pci_dev *hwdev, size_t size,
  34. void *vaddr, dma_addr_t dma_handle)
  35. {
  36. void *alloc;
  37. alloc = bus_to_virt((unsigned long)dma_handle);
  38. free_pages((unsigned long)alloc, get_order(size));
  39. iounmap(vaddr);
  40. }