dma.c 958 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/device.h>
  11. #include <linux/dma-mapping.h>
  12. #include <asm/io.h>
  13. void *dma_alloc_coherent(struct device *dev, size_t size,
  14. dma_addr_t *dma_handle, gfp_t gfp)
  15. {
  16. void *ret;
  17. /* ignore region specifiers */
  18. gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  19. if (dev == NULL || (*dev->dma_mask < 0xffffffff))
  20. gfp |= GFP_DMA;
  21. ret = (void *)__get_free_pages(gfp, get_order(size));
  22. if (ret != NULL) {
  23. memset(ret, 0, size);
  24. *dma_handle = virt_to_phys(ret);
  25. }
  26. return ret;
  27. }
  28. void dma_free_coherent(struct device *dev, size_t size,
  29. void *vaddr, dma_addr_t dma_handle)
  30. {
  31. free_pages((unsigned long)vaddr, get_order(size));
  32. }
  33. void dma_sync_single_for_cpu(struct device *dev, dma_addr_t handle, size_t size, enum dma_data_direction dir)
  34. {
  35. }