dma.c 783 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 <asm/io.h>
  11. void *dma_alloc_coherent(struct device *dev, size_t size,
  12. dma_addr_t *dma_handle, int gfp)
  13. {
  14. void *ret;
  15. /* ignore region specifiers */
  16. gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  17. if (dev == NULL || (*dev->dma_mask < 0xffffffff))
  18. gfp |= GFP_DMA;
  19. ret = (void *)__get_free_pages(gfp, get_order(size));
  20. if (ret != NULL) {
  21. memset(ret, 0, size);
  22. *dma_handle = virt_to_phys(ret);
  23. }
  24. return ret;
  25. }
  26. void dma_free_coherent(struct device *dev, size_t size,
  27. void *vaddr, dma_addr_t dma_handle)
  28. {
  29. free_pages((unsigned long)vaddr, get_order(size));
  30. }