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_addr, 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
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