1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Re-map IO memory to kernel address space so that we can access it. |
4 | * |
5 | * These functions should only be used when it is necessary to map a |
6 | * physical address space into the kernel address space before ioremap() |
7 | * can be used, e.g. early in boot before paging_init(). |
8 | * |
9 | * Copyright (C) 2009 Matt Fleming |
10 | */ |
11 | |
12 | #include <linux/vmalloc.h> |
13 | #include <linux/ioport.h> |
14 | #include <linux/module.h> |
15 | #include <linux/mm.h> |
16 | #include <linux/io.h> |
17 | #include <linux/memblock.h> |
18 | #include <linux/proc_fs.h> |
19 | #include <asm/fixmap.h> |
20 | #include <asm/page.h> |
21 | #include <asm/addrspace.h> |
22 | #include <asm/cacheflush.h> |
23 | #include <asm/tlbflush.h> |
24 | #include <asm/mmu.h> |
25 | #include <asm/mmu_context.h> |
26 | #include "ioremap.h" |
27 | |
28 | struct ioremap_map { |
29 | void __iomem *addr; |
30 | unsigned long size; |
31 | unsigned long fixmap_addr; |
32 | }; |
33 | |
34 | static struct ioremap_map ioremap_maps[FIX_N_IOREMAPS]; |
35 | |
36 | void __init ioremap_fixed_init(void) |
37 | { |
38 | struct ioremap_map *map; |
39 | int i; |
40 | |
41 | for (i = 0; i < FIX_N_IOREMAPS; i++) { |
42 | map = &ioremap_maps[i]; |
43 | map->fixmap_addr = __fix_to_virt(FIX_IOREMAP_BEGIN + i); |
44 | } |
45 | } |
46 | |
47 | void __init __iomem * |
48 | ioremap_fixed(phys_addr_t phys_addr, unsigned long size, pgprot_t prot) |
49 | { |
50 | enum fixed_addresses idx0, idx; |
51 | struct ioremap_map *map; |
52 | unsigned int nrpages; |
53 | unsigned long offset; |
54 | int i, slot; |
55 | |
56 | /* |
57 | * Mappings have to be page-aligned |
58 | */ |
59 | offset = phys_addr & ~PAGE_MASK; |
60 | phys_addr &= PAGE_MASK; |
61 | size = PAGE_ALIGN(phys_addr + size) - phys_addr; |
62 | |
63 | slot = -1; |
64 | for (i = 0; i < FIX_N_IOREMAPS; i++) { |
65 | map = &ioremap_maps[i]; |
66 | if (!map->addr) { |
67 | map->size = size; |
68 | slot = i; |
69 | break; |
70 | } |
71 | } |
72 | |
73 | if (slot < 0) |
74 | return NULL; |
75 | |
76 | /* |
77 | * Mappings have to fit in the FIX_IOREMAP area. |
78 | */ |
79 | nrpages = size >> PAGE_SHIFT; |
80 | if (nrpages > FIX_N_IOREMAPS) |
81 | return NULL; |
82 | |
83 | /* |
84 | * Ok, go for it.. |
85 | */ |
86 | idx0 = FIX_IOREMAP_BEGIN + slot; |
87 | idx = idx0; |
88 | while (nrpages > 0) { |
89 | pgprot_val(prot) |= _PAGE_WIRED; |
90 | __set_fixmap(idx, phys: phys_addr, flags: prot); |
91 | phys_addr += PAGE_SIZE; |
92 | idx++; |
93 | --nrpages; |
94 | } |
95 | |
96 | map->addr = (void __iomem *)(offset + map->fixmap_addr); |
97 | return map->addr; |
98 | } |
99 | |
100 | int iounmap_fixed(void __iomem *addr) |
101 | { |
102 | enum fixed_addresses idx; |
103 | struct ioremap_map *map; |
104 | unsigned int nrpages; |
105 | int i, slot; |
106 | |
107 | slot = -1; |
108 | for (i = 0; i < FIX_N_IOREMAPS; i++) { |
109 | map = &ioremap_maps[i]; |
110 | if (map->addr == addr) { |
111 | slot = i; |
112 | break; |
113 | } |
114 | } |
115 | |
116 | /* |
117 | * If we don't match, it's not for us. |
118 | */ |
119 | if (slot < 0) |
120 | return -EINVAL; |
121 | |
122 | nrpages = map->size >> PAGE_SHIFT; |
123 | |
124 | idx = FIX_IOREMAP_BEGIN + slot + nrpages - 1; |
125 | while (nrpages > 0) { |
126 | __clear_fixmap(idx, __pgprot(_PAGE_WIRED)); |
127 | --idx; |
128 | --nrpages; |
129 | } |
130 | |
131 | map->size = 0; |
132 | map->addr = NULL; |
133 | |
134 | return 0; |
135 | } |
136 | |