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/*
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