drivers/pci/mmap.c

   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
  10 #include <linux/kernel.h>
  11 #include <linux/mm.h>
  12 #include <linux/pci.h>
  13
  14 #include "pci.h"
  15
  16 #ifdef ARCH_GENERIC_PCI_MMAP_RESOURCE
  17
  18 static const struct vm_operations_struct pci_phys_vm_ops = {
  19 #ifdef CONFIG_HAVE_IOREMAP_PROT
  20         .access = generic_access_phys,
  21 #endif
  22 };
  23
  24 int pci_mmap_resource_range(struct pci_dev *pdev, int bar,
  25                             struct vm_area_struct *vma,
  26                             enum pci_mmap_state mmap_state, int write_combine)
  27 {
  28         unsigned long size;
  29         int ret;
  30
  31         size = ((pci_resource_len(pdev, bar) - 1) >> PAGE_SHIFT) + 1;
  32         if (vma->vm_pgoff + vma_pages(vma) > size)
  33                 return -EINVAL;
  34
  35         if (write_combine)
  36                 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
  37         else
  38                 vma->vm_page_prot = pgprot_device(vma->vm_page_prot);
  39
  40         if (mmap_state == pci_mmap_io) {
  41                 ret = pci_iobar_pfn(pdev, bar, vma);
  42                 if (ret)
  43                         return ret;
  44         } else
  45                 vma->vm_pgoff += (pci_resource_start(pdev, bar) >> PAGE_SHIFT);
  46
  47         vma->vm_ops = &pci_phys_vm_ops;
  48
  49         return io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
  50                                   vma->vm_end - vma->vm_start,
  51                                   vma->vm_page_prot);
  52 }
  53
  54 #endif
  55
  56 #if (defined(CONFIG_SYSFS) || defined(CONFIG_PROC_FS)) && \
  57     (defined(HAVE_PCI_MMAP) || defined(ARCH_GENERIC_PCI_MMAP_RESOURCE))
  58
  59 int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vma,
  60                   enum pci_mmap_api mmap_api)
  61 {
  62         resource_size_t pci_start = 0, pci_end;
  63         unsigned long nr, start, size;
  64
  65         if (pci_resource_len(pdev, resno) == 0)
  66                 return 0;
  67         nr = vma_pages(vma);
  68         start = vma->vm_pgoff;
  69         size = ((pci_resource_len(pdev, resno) - 1) >> PAGE_SHIFT) + 1;
  70         if (mmap_api == PCI_MMAP_PROCFS) {
  71                 pci_resource_to_user(pdev, resno, &pdev->resource[resno],
  72                                      &pci_start, &pci_end);
  73                 pci_start >>= PAGE_SHIFT;
  74         }
  75         if (start >= pci_start && start < pci_start + size &&
  76             start + nr <= pci_start + size)
  77                 return 1;
  78         return 0;
  79 }
  80
  81 #endif