remap.c 1.6 KB

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  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * Copyright (c) 2014 The Linux Foundation
  4. */
  5. #include <linux/dma-map-ops.h>
  6. #include <linux/slab.h>
  7. #include <linux/vmalloc.h>
  8. struct page **dma_common_find_pages(void *cpu_addr)
  9. {
  10. struct vm_struct *area = find_vm_area(cpu_addr);
  11. if (!area || area->flags != VM_DMA_COHERENT)
  12. return NULL;
  13. return area->pages;
  14. }
  15. /*
  16. * Remaps an array of PAGE_SIZE pages into another vm_area.
  17. * Cannot be used in non-sleeping contexts
  18. */
  19. void *dma_common_pages_remap(struct page **pages, size_t size,
  20. pgprot_t prot, const void *caller)
  21. {
  22. void *vaddr;
  23. vaddr = vmap(pages, PAGE_ALIGN(size) >> PAGE_SHIFT,
  24. VM_DMA_COHERENT, prot);
  25. if (vaddr)
  26. find_vm_area(vaddr)->pages = pages;
  27. return vaddr;
  28. }
  29. /*
  30. * Remaps an allocated contiguous region into another vm_area.
  31. * Cannot be used in non-sleeping contexts
  32. */
  33. void *dma_common_contiguous_remap(struct page *page, size_t size,
  34. pgprot_t prot, const void *caller)
  35. {
  36. int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
  37. struct page **pages;
  38. void *vaddr;
  39. int i;
  40. pages = kmalloc_array(count, sizeof(struct page *), GFP_KERNEL);
  41. if (!pages)
  42. return NULL;
  43. for (i = 0; i < count; i++)
  44. pages[i] = nth_page(page, i);
  45. vaddr = vmap(pages, count, VM_DMA_COHERENT, prot);
  46. kfree(pages);
  47. return vaddr;
  48. }
  49. /*
  50. * Unmaps a range previously mapped by dma_common_*_remap
  51. */
  52. void dma_common_free_remap(void *cpu_addr, size_t size)
  53. {
  54. struct vm_struct *area = find_vm_area(cpu_addr);
  55. if (!area || area->flags != VM_DMA_COHERENT) {
  56. WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
  57. return;
  58. }
  59. unmap_kernel_range((unsigned long)cpu_addr, PAGE_ALIGN(size));
  60. vunmap(cpu_addr);
  61. }