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f7195824 DW |
1 | /* |
2 | * mmap.c — generic PCI resource mmap helper | |
3 | * | |
4 | * Copyright © 2017 Amazon.com, Inc. or its affiliates. | |
5 | * | |
6 | * Author: David Woodhouse <dwmw2@infradead.org> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/kernel.h> | |
14 | #include <linux/mm.h> | |
15 | #include <linux/pci.h> | |
16 | ||
17 | #ifdef ARCH_GENERIC_PCI_MMAP_RESOURCE | |
18 | ||
19 | /* | |
20 | * Modern setup: generic pci_mmap_resource_range(), and implement the legacy | |
21 | * pci_mmap_page_range() (if needed) as a wrapper round it. | |
22 | */ | |
23 | ||
24 | #ifdef HAVE_PCI_MMAP | |
25 | int pci_mmap_page_range(struct pci_dev *pdev, int bar, | |
26 | struct vm_area_struct *vma, | |
27 | enum pci_mmap_state mmap_state, int write_combine) | |
28 | { | |
29 | resource_size_t start, end; | |
30 | ||
31 | pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end); | |
32 | ||
33 | /* Adjust vm_pgoff to be the offset within the resource */ | |
34 | vma->vm_pgoff -= start >> PAGE_SHIFT; | |
35 | return pci_mmap_resource_range(pdev, bar, vma, mmap_state, | |
36 | write_combine); | |
37 | } | |
38 | #endif | |
39 | ||
40 | static const struct vm_operations_struct pci_phys_vm_ops = { | |
41 | #ifdef CONFIG_HAVE_IOREMAP_PROT | |
42 | .access = generic_access_phys, | |
43 | #endif | |
44 | }; | |
45 | ||
46 | int pci_mmap_resource_range(struct pci_dev *pdev, int bar, | |
47 | struct vm_area_struct *vma, | |
48 | enum pci_mmap_state mmap_state, int write_combine) | |
49 | { | |
50 | unsigned long size; | |
2bea36fd | 51 | int ret; |
f7195824 DW |
52 | |
53 | size = ((pci_resource_len(pdev, bar) - 1) >> PAGE_SHIFT) + 1; | |
54 | if (vma->vm_pgoff + vma_pages(vma) > size) | |
55 | return -EINVAL; | |
56 | ||
57 | if (write_combine) | |
58 | vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); | |
59 | else | |
60 | vma->vm_page_prot = pgprot_device(vma->vm_page_prot); | |
61 | ||
2bea36fd DW |
62 | if (mmap_state == pci_mmap_io) { |
63 | ret = pci_iobar_pfn(pdev, bar, vma); | |
64 | if (ret) | |
65 | return ret; | |
66 | } else | |
67 | vma->vm_pgoff += (pci_resource_start(pdev, bar) >> PAGE_SHIFT); | |
68 | ||
f7195824 DW |
69 | vma->vm_ops = &pci_phys_vm_ops; |
70 | ||
71 | return io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, | |
72 | vma->vm_end - vma->vm_start, | |
73 | vma->vm_page_prot); | |
74 | } | |
75 | ||
76 | #elif defined(HAVE_PCI_MMAP) /* && !ARCH_GENERIC_PCI_MMAP_RESOURCE */ | |
77 | ||
78 | /* | |
79 | * Legacy setup: Impement pci_mmap_resource_range() as a wrapper around | |
80 | * the architecture's pci_mmap_page_range(), converting to "user visible" | |
81 | * addresses as necessary. | |
82 | */ | |
83 | ||
84 | int pci_mmap_resource_range(struct pci_dev *pdev, int bar, | |
85 | struct vm_area_struct *vma, | |
86 | enum pci_mmap_state mmap_state, int write_combine) | |
87 | { | |
88 | resource_size_t start, end; | |
89 | ||
90 | /* | |
91 | * pci_mmap_page_range() expects the same kind of entry as coming | |
92 | * from /proc/bus/pci/ which is a "user visible" value. If this is | |
93 | * different from the resource itself, arch will do necessary fixup. | |
94 | */ | |
95 | pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end); | |
96 | vma->vm_pgoff += start >> PAGE_SHIFT; | |
97 | return pci_mmap_page_range(pdev, bar, vma, mmap_state, write_combine); | |
98 | } | |
99 | #endif |