dma_no.c 1.8 KB

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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/gfp.h>
  9. #include <linux/mm.h>
  10. #include <linux/device.h>
  11. #include <linux/dma-mapping.h>
  12. #include <linux/export.h>
  13. #include <asm/cacheflush.h>
  14. void *dma_alloc_coherent(struct device *dev, size_t size,
  15. dma_addr_t *dma_handle, gfp_t gfp)
  16. {
  17. void *ret;
  18. /* ignore region specifiers */
  19. gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  20. if (dev == NULL || (*dev->dma_mask < 0xffffffff))
  21. gfp |= GFP_DMA;
  22. ret = (void *)__get_free_pages(gfp, get_order(size));
  23. if (ret != NULL) {
  24. memset(ret, 0, size);
  25. *dma_handle = virt_to_phys(ret);
  26. }
  27. return ret;
  28. }
  29. void dma_free_coherent(struct device *dev, size_t size,
  30. void *vaddr, dma_addr_t dma_handle)
  31. {
  32. free_pages((unsigned long)vaddr, get_order(size));
  33. }
  34. void dma_sync_single_for_device(struct device *dev, dma_addr_t handle,
  35. size_t size, enum dma_data_direction dir)
  36. {
  37. switch (dir) {
  38. case DMA_TO_DEVICE:
  39. flush_dcache_range(handle, size);
  40. break;
  41. case DMA_FROM_DEVICE:
  42. /* Should be clear already */
  43. break;
  44. default:
  45. if (printk_ratelimit())
  46. printk("dma_sync_single_for_device: unsupported dir %u\n", dir);
  47. break;
  48. }
  49. }
  50. EXPORT_SYMBOL(dma_sync_single_for_device);
  51. dma_addr_t dma_map_single(struct device *dev, void *addr, size_t size,
  52. enum dma_data_direction dir)
  53. {
  54. dma_addr_t handle = virt_to_phys(addr);
  55. flush_dcache_range(handle, size);
  56. return handle;
  57. }
  58. EXPORT_SYMBOL(dma_map_single);
  59. dma_addr_t dma_map_page(struct device *dev, struct page *page,
  60. unsigned long offset, size_t size,
  61. enum dma_data_direction dir)
  62. {
  63. dma_addr_t handle = page_to_phys(page) + offset;
  64. dma_sync_single_for_device(dev, handle, size, dir);
  65. return handle;
  66. }
  67. EXPORT_SYMBOL(dma_map_page);