mmap.c 2.6 KB

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  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * Generic PCI resource mmap helper
  4. *
  5. * Copyright © 2017 Amazon.com, Inc. or its affiliates.
  6. *
  7. * Author: David Woodhouse <dwmw2@infradead.org>
  8. */
  9. #include <linux/kernel.h>
  10. #include <linux/mm.h>
  11. #include <linux/pci.h>
  12. #ifdef ARCH_GENERIC_PCI_MMAP_RESOURCE
  13. /*
  14. * Modern setup: generic pci_mmap_resource_range(), and implement the legacy
  15. * pci_mmap_page_range() (if needed) as a wrapper round it.
  16. */
  17. #ifdef HAVE_PCI_MMAP
  18. int pci_mmap_page_range(struct pci_dev *pdev, int bar,
  19. struct vm_area_struct *vma,
  20. enum pci_mmap_state mmap_state, int write_combine)
  21. {
  22. resource_size_t start, end;
  23. pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end);
  24. /* Adjust vm_pgoff to be the offset within the resource */
  25. vma->vm_pgoff -= start >> PAGE_SHIFT;
  26. return pci_mmap_resource_range(pdev, bar, vma, mmap_state,
  27. write_combine);
  28. }
  29. #endif
  30. static const struct vm_operations_struct pci_phys_vm_ops = {
  31. #ifdef CONFIG_HAVE_IOREMAP_PROT
  32. .access = generic_access_phys,
  33. #endif
  34. };
  35. int pci_mmap_resource_range(struct pci_dev *pdev, int bar,
  36. struct vm_area_struct *vma,
  37. enum pci_mmap_state mmap_state, int write_combine)
  38. {
  39. unsigned long size;
  40. int ret;
  41. size = ((pci_resource_len(pdev, bar) - 1) >> PAGE_SHIFT) + 1;
  42. if (vma->vm_pgoff + vma_pages(vma) > size)
  43. return -EINVAL;
  44. if (write_combine)
  45. vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
  46. else
  47. vma->vm_page_prot = pgprot_device(vma->vm_page_prot);
  48. if (mmap_state == pci_mmap_io) {
  49. ret = pci_iobar_pfn(pdev, bar, vma);
  50. if (ret)
  51. return ret;
  52. } else
  53. vma->vm_pgoff += (pci_resource_start(pdev, bar) >> PAGE_SHIFT);
  54. vma->vm_ops = &pci_phys_vm_ops;
  55. return io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
  56. vma->vm_end - vma->vm_start,
  57. vma->vm_page_prot);
  58. }
  59. #elif defined(HAVE_PCI_MMAP) /* && !ARCH_GENERIC_PCI_MMAP_RESOURCE */
  60. /*
  61. * Legacy setup: Implement pci_mmap_resource_range() as a wrapper around
  62. * the architecture's pci_mmap_page_range(), converting to "user visible"
  63. * addresses as necessary.
  64. */
  65. int pci_mmap_resource_range(struct pci_dev *pdev, int bar,
  66. struct vm_area_struct *vma,
  67. enum pci_mmap_state mmap_state, int write_combine)
  68. {
  69. resource_size_t start, end;
  70. /*
  71. * pci_mmap_page_range() expects the same kind of entry as coming
  72. * from /proc/bus/pci/ which is a "user visible" value. If this is
  73. * different from the resource itself, arch will do necessary fixup.
  74. */
  75. pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end);
  76. vma->vm_pgoff += start >> PAGE_SHIFT;
  77. return pci_mmap_page_range(pdev, bar, vma, mmap_state, write_combine);
  78. }
  79. #endif