linux/drivers/pci/mmap.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Generic PCI resource mmap helper
   4 *
   5 * Copyright \xC2\xA9 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/*
  17 * Modern setup: generic pci_mmap_resource_range(), and implement the legacy
  18 * pci_mmap_page_range() (if needed) as a wrapper round it.
  19 */
  20
  21#ifdef HAVE_PCI_MMAP
  22int pci_mmap_page_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        resource_size_t start, end;
  27
  28        pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end);
  29
  30        /* Adjust vm_pgoff to be the offset within the resource */
  31        vma->vm_pgoff -= start >> PAGE_SHIFT;
  32        return pci_mmap_resource_range(pdev, bar, vma, mmap_state,
  33                                       write_combine);
  34}
  35#endif
  36
  37static const struct vm_operations_struct pci_phys_vm_ops = {
  38#ifdef CONFIG_HAVE_IOREMAP_PROT
  39        .access = generic_access_phys,
  40#endif
  41};
  42
  43int pci_mmap_resource_range(struct pci_dev *pdev, int bar,
  44                            struct vm_area_struct *vma,
  45                            enum pci_mmap_state mmap_state, int write_combine)
  46{
  47        unsigned long size;
  48        int ret;
  49
  50        size = ((pci_resource_len(pdev, bar) - 1) >> PAGE_SHIFT) + 1;
  51        if (vma->vm_pgoff + vma_pages(vma) > size)
  52                return -EINVAL;
  53
  54        if (write_combine)
  55                vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
  56        else
  57                vma->vm_page_prot = pgprot_device(vma->vm_page_prot);
  58
  59        if (mmap_state == pci_mmap_io) {
  60                ret = pci_iobar_pfn(pdev, bar, vma);
  61                if (ret)
  62                        return ret;
  63        } else
  64                vma->vm_pgoff += (pci_resource_start(pdev, bar) >> PAGE_SHIFT);
  65
  66        vma->vm_ops = &pci_phys_vm_ops;
  67
  68        return io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
  69                                  vma->vm_end - vma->vm_start,
  70                                  vma->vm_page_prot);
  71}
  72
  73#elif defined(HAVE_PCI_MMAP) /* && !ARCH_GENERIC_PCI_MMAP_RESOURCE */
  74
  75/*
  76 * Legacy setup: Implement pci_mmap_resource_range() as a wrapper around
  77 * the architecture's pci_mmap_page_range(), converting to "user visible"
  78 * addresses as necessary.
  79 */
  80
  81int pci_mmap_resource_range(struct pci_dev *pdev, int bar,
  82                            struct vm_area_struct *vma,
  83                            enum pci_mmap_state mmap_state, int write_combine)
  84{
  85        resource_size_t start, end;
  86
  87        /*
  88         * pci_mmap_page_range() expects the same kind of entry as coming
  89         * from /proc/bus/pci/ which is a "user visible" value. If this is
  90         * different from the resource itself, arch will do necessary fixup.
  91         */
  92        pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end);
  93        vma->vm_pgoff += start >> PAGE_SHIFT;
  94        return pci_mmap_page_range(pdev, bar, vma, mmap_state, write_combine);
  95}
  96#endif
  97