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 #ifdef ARCH_GENERIC_PCI_MMAP_RESOURCE
  15
  16 static const struct vm_operations_struct pci_phys_vm_ops = {
  17 #ifdef CONFIG_HAVE_IOREMAP_PROT
  18         .access = generic_access_phys,
  19 #endif
  20 };
  21
  22 int pci_mmap_resource_range(struct pci_dev *pdev, int bar,
  23                             struct vm_area_struct *vma,
  24                             enum pci_mmap_state mmap_state, int write_combine)
  25 {
  26         unsigned long size;
  27         int ret;
  28
  29         size = ((pci_resource_len(pdev, bar) - 1) >> PAGE_SHIFT) + 1;
  30         if (vma->vm_pgoff + vma_pages(vma) > size)
  31                 return -EINVAL;
  32
  33         if (write_combine)
  34                 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
  35         else
  36                 vma->vm_page_prot = pgprot_device(vma->vm_page_prot);
  37
  38         if (mmap_state == pci_mmap_io) {
  39                 ret = pci_iobar_pfn(pdev, bar, vma);
  40                 if (ret)
  41                         return ret;
  42         } else
  43                 vma->vm_pgoff += (pci_resource_start(pdev, bar) >> PAGE_SHIFT);
  44
  45         vma->vm_ops = &pci_phys_vm_ops;
  46
  47         return io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
  48                                   vma->vm_end - vma->vm_start,
  49                                   vma->vm_page_prot);
  50 }
  51
  52 #endif