ioremap.c 2.1 KB

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  1. /*
  2. * Re-map IO memory to kernel address space so that we can access it.
  3. * This is needed for high PCI addresses that aren't mapped in the
  4. * 640k-1MB IO memory area on PC's
  5. *
  6. * (C) Copyright 1995 1996 Linus Torvalds
  7. */
  8. #include <linux/vmalloc.h>
  9. #include <linux/mm.h>
  10. #include <asm/cacheflush.h>
  11. #include <asm/pgtable.h>
  12. static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
  13. unsigned long end, unsigned long phys_addr, pgprot_t prot)
  14. {
  15. pte_t *pte;
  16. unsigned long pfn;
  17. pfn = phys_addr >> PAGE_SHIFT;
  18. pte = pte_alloc_kernel(pmd, addr);
  19. if (!pte)
  20. return -ENOMEM;
  21. do {
  22. BUG_ON(!pte_none(*pte));
  23. set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
  24. pfn++;
  25. } while (pte++, addr += PAGE_SIZE, addr != end);
  26. return 0;
  27. }
  28. static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
  29. unsigned long end, unsigned long phys_addr, pgprot_t prot)
  30. {
  31. pmd_t *pmd;
  32. unsigned long next;
  33. phys_addr -= addr;
  34. pmd = pmd_alloc(&init_mm, pud, addr);
  35. if (!pmd)
  36. return -ENOMEM;
  37. do {
  38. next = pmd_addr_end(addr, end);
  39. if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot))
  40. return -ENOMEM;
  41. } while (pmd++, addr = next, addr != end);
  42. return 0;
  43. }
  44. static inline int ioremap_pud_range(pgd_t *pgd, unsigned long addr,
  45. unsigned long end, unsigned long phys_addr, pgprot_t prot)
  46. {
  47. pud_t *pud;
  48. unsigned long next;
  49. phys_addr -= addr;
  50. pud = pud_alloc(&init_mm, pgd, addr);
  51. if (!pud)
  52. return -ENOMEM;
  53. do {
  54. next = pud_addr_end(addr, end);
  55. if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot))
  56. return -ENOMEM;
  57. } while (pud++, addr = next, addr != end);
  58. return 0;
  59. }
  60. int ioremap_page_range(unsigned long addr,
  61. unsigned long end, unsigned long phys_addr, pgprot_t prot)
  62. {
  63. pgd_t *pgd;
  64. unsigned long start;
  65. unsigned long next;
  66. int err;
  67. BUG_ON(addr >= end);
  68. start = addr;
  69. phys_addr -= addr;
  70. pgd = pgd_offset_k(addr);
  71. do {
  72. next = pgd_addr_end(addr, end);
  73. err = ioremap_pud_range(pgd, addr, next, phys_addr+addr, prot);
  74. if (err)
  75. break;
  76. } while (pgd++, addr = next, addr != end);
  77. flush_cache_vmap(start, end);
  78. return err;
  79. }