dma.c 806 B

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  1. /*
  2. * Dynamic DMA mapping support.
  3. *
  4. * We never have any address translations to worry about, so this
  5. * is just alloc/free.
  6. */
  7. #include <linux/types.h>
  8. #include <linux/mm.h>
  9. #include <linux/string.h>
  10. #include <linux/pci.h>
  11. #include <asm/io.h>
  12. void *dma_alloc_coherent(struct device *dev, size_t size,
  13. dma_addr_t *dma_handle, int gfp)
  14. {
  15. void *ret;
  16. /* ignore region specifiers */
  17. gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  18. if (dev == NULL || (*dev->dma_mask < 0xffffffff))
  19. gfp |= GFP_DMA;
  20. ret = (void *)__get_free_pages(gfp, get_order(size));
  21. if (ret != NULL) {
  22. memset(ret, 0, size);
  23. *dma_handle = virt_to_phys(ret);
  24. }
  25. return ret;
  26. }
  27. void dma_free_coherent(struct device *dev, size_t size,
  28. void *vaddr, dma_addr_t dma_handle)
  29. {
  30. free_pages((unsigned long)vaddr, get_order(size));
  31. }