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5f97f7f9 HS |
1 | /* |
2 | * Copyright (C) 2004-2006 Atmel Corporation | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | */ | |
8 | #include <linux/vmalloc.h> | |
9 | #include <linux/module.h> | |
10 | ||
11 | #include <asm/io.h> | |
12 | #include <asm/pgtable.h> | |
13 | #include <asm/cacheflush.h> | |
14 | #include <asm/tlbflush.h> | |
15 | #include <asm/addrspace.h> | |
16 | ||
17 | static inline int remap_area_pte(pte_t *pte, unsigned long address, | |
18 | unsigned long end, unsigned long phys_addr, | |
19 | pgprot_t prot) | |
20 | { | |
21 | unsigned long pfn; | |
22 | ||
23 | pfn = phys_addr >> PAGE_SHIFT; | |
24 | do { | |
25 | WARN_ON(!pte_none(*pte)); | |
26 | ||
27 | set_pte(pte, pfn_pte(pfn, prot)); | |
28 | address += PAGE_SIZE; | |
29 | pfn++; | |
30 | pte++; | |
31 | } while (address && (address < end)); | |
32 | ||
33 | return 0; | |
34 | } | |
35 | ||
36 | static inline int remap_area_pmd(pmd_t *pmd, unsigned long address, | |
37 | unsigned long end, unsigned long phys_addr, | |
38 | pgprot_t prot) | |
39 | { | |
40 | unsigned long next; | |
41 | ||
42 | phys_addr -= address; | |
43 | ||
44 | do { | |
45 | pte_t *pte = pte_alloc_kernel(pmd, address); | |
46 | if (!pte) | |
47 | return -ENOMEM; | |
48 | ||
49 | next = (address + PMD_SIZE) & PMD_MASK; | |
50 | if (remap_area_pte(pte, address, next, | |
51 | address + phys_addr, prot)) | |
52 | return -ENOMEM; | |
53 | ||
54 | address = next; | |
55 | pmd++; | |
56 | } while (address && (address < end)); | |
57 | return 0; | |
58 | } | |
59 | ||
60 | static int remap_area_pud(pud_t *pud, unsigned long address, | |
61 | unsigned long end, unsigned long phys_addr, | |
62 | pgprot_t prot) | |
63 | { | |
64 | unsigned long next; | |
65 | ||
66 | phys_addr -= address; | |
67 | ||
68 | do { | |
69 | pmd_t *pmd = pmd_alloc(&init_mm, pud, address); | |
70 | if (!pmd) | |
71 | return -ENOMEM; | |
72 | next = (address + PUD_SIZE) & PUD_MASK; | |
73 | if (remap_area_pmd(pmd, address, next, | |
74 | phys_addr + address, prot)) | |
75 | return -ENOMEM; | |
76 | ||
77 | address = next; | |
78 | pud++; | |
79 | } while (address && address < end); | |
80 | ||
81 | return 0; | |
82 | } | |
83 | ||
84 | static int remap_area_pages(unsigned long address, unsigned long phys_addr, | |
85 | size_t size, pgprot_t prot) | |
86 | { | |
87 | unsigned long end = address + size; | |
88 | unsigned long next; | |
89 | pgd_t *pgd; | |
90 | int err = 0; | |
91 | ||
92 | phys_addr -= address; | |
93 | ||
94 | pgd = pgd_offset_k(address); | |
95 | flush_cache_all(); | |
96 | BUG_ON(address >= end); | |
97 | ||
98 | spin_lock(&init_mm.page_table_lock); | |
99 | do { | |
100 | pud_t *pud = pud_alloc(&init_mm, pgd, address); | |
101 | ||
102 | err = -ENOMEM; | |
103 | if (!pud) | |
104 | break; | |
105 | ||
106 | next = (address + PGDIR_SIZE) & PGDIR_MASK; | |
107 | if (next < address || next > end) | |
108 | next = end; | |
109 | err = remap_area_pud(pud, address, next, | |
110 | phys_addr + address, prot); | |
111 | if (err) | |
112 | break; | |
113 | ||
114 | address = next; | |
115 | pgd++; | |
116 | } while (address && (address < end)); | |
117 | ||
118 | spin_unlock(&init_mm.page_table_lock); | |
119 | flush_tlb_all(); | |
120 | return err; | |
121 | } | |
122 | ||
123 | /* | |
124 | * Re-map an arbitrary physical address space into the kernel virtual | |
125 | * address space. Needed when the kernel wants to access physical | |
126 | * memory directly. | |
127 | */ | |
128 | void __iomem *__ioremap(unsigned long phys_addr, size_t size, | |
129 | unsigned long flags) | |
130 | { | |
131 | void *addr; | |
132 | struct vm_struct *area; | |
133 | unsigned long offset, last_addr; | |
134 | pgprot_t prot; | |
135 | ||
136 | /* | |
137 | * Check if we can simply use the P4 segment. This area is | |
138 | * uncacheable, so if caching/buffering is requested, we can't | |
139 | * use it. | |
140 | */ | |
141 | if ((phys_addr >= P4SEG) && (flags == 0)) | |
142 | return (void __iomem *)phys_addr; | |
143 | ||
144 | /* Don't allow wraparound or zero size */ | |
145 | last_addr = phys_addr + size - 1; | |
146 | if (!size || last_addr < phys_addr) | |
147 | return NULL; | |
148 | ||
149 | /* | |
150 | * XXX: When mapping regular RAM, we'd better make damn sure | |
151 | * it's never used for anything else. But this is really the | |
152 | * caller's responsibility... | |
153 | */ | |
154 | if (PHYSADDR(P2SEGADDR(phys_addr)) == phys_addr) | |
155 | return (void __iomem *)P2SEGADDR(phys_addr); | |
156 | ||
157 | /* Mappings have to be page-aligned */ | |
158 | offset = phys_addr & ~PAGE_MASK; | |
159 | phys_addr &= PAGE_MASK; | |
160 | size = PAGE_ALIGN(last_addr + 1) - phys_addr; | |
161 | ||
162 | prot = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | |
163 | | _PAGE_ACCESSED | _PAGE_TYPE_SMALL | flags); | |
164 | ||
165 | /* | |
166 | * Ok, go for it.. | |
167 | */ | |
168 | area = get_vm_area(size, VM_IOREMAP); | |
169 | if (!area) | |
170 | return NULL; | |
171 | area->phys_addr = phys_addr; | |
172 | addr = area->addr; | |
173 | if (remap_area_pages((unsigned long)addr, phys_addr, size, prot)) { | |
174 | vunmap(addr); | |
175 | return NULL; | |
176 | } | |
177 | ||
178 | return (void __iomem *)(offset + (char *)addr); | |
179 | } | |
180 | EXPORT_SYMBOL(__ioremap); | |
181 | ||
182 | void __iounmap(void __iomem *addr) | |
183 | { | |
184 | struct vm_struct *p; | |
185 | ||
186 | if ((unsigned long)addr >= P4SEG) | |
187 | return; | |
188 | ||
189 | p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr)); | |
190 | if (unlikely(!p)) { | |
191 | printk (KERN_ERR "iounmap: bad address %p\n", addr); | |
192 | return; | |
193 | } | |
194 | ||
195 | kfree (p); | |
196 | } | |
197 | EXPORT_SYMBOL(__iounmap); |