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1da177e4 LT |
1 | /* |
2 | * This file is subject to the terms and conditions of the GNU General Public | |
3 | * License. See the file "COPYING" in the main directory of this archive | |
4 | * for more details. | |
5 | * | |
6 | * (C) Copyright 1995 1996 Linus Torvalds | |
7 | * (C) Copyright 2001, 2002 Ralf Baechle | |
8 | */ | |
9 | #include <linux/module.h> | |
10 | #include <asm/addrspace.h> | |
11 | #include <asm/byteorder.h> | |
12 | ||
13 | #include <linux/vmalloc.h> | |
14 | #include <asm/cacheflush.h> | |
15 | #include <asm/io.h> | |
16 | #include <asm/tlbflush.h> | |
17 | ||
18 | static inline void remap_area_pte(pte_t * pte, unsigned long address, | |
19 | phys_t size, phys_t phys_addr, unsigned long flags) | |
20 | { | |
21 | phys_t end; | |
22 | unsigned long pfn; | |
23 | pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | __READABLE | |
24 | | __WRITEABLE | flags); | |
25 | ||
26 | address &= ~PMD_MASK; | |
27 | end = address + size; | |
28 | if (end > PMD_SIZE) | |
29 | end = PMD_SIZE; | |
30 | if (address >= end) | |
31 | BUG(); | |
32 | pfn = phys_addr >> PAGE_SHIFT; | |
33 | do { | |
34 | if (!pte_none(*pte)) { | |
35 | printk("remap_area_pte: page already exists\n"); | |
36 | BUG(); | |
37 | } | |
38 | set_pte(pte, pfn_pte(pfn, pgprot)); | |
39 | address += PAGE_SIZE; | |
40 | pfn++; | |
41 | pte++; | |
42 | } while (address && (address < end)); | |
43 | } | |
44 | ||
45 | static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, | |
46 | phys_t size, phys_t phys_addr, unsigned long flags) | |
47 | { | |
48 | phys_t end; | |
49 | ||
50 | address &= ~PGDIR_MASK; | |
51 | end = address + size; | |
52 | if (end > PGDIR_SIZE) | |
53 | end = PGDIR_SIZE; | |
54 | phys_addr -= address; | |
55 | if (address >= end) | |
56 | BUG(); | |
57 | do { | |
58 | pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address); | |
59 | if (!pte) | |
60 | return -ENOMEM; | |
61 | remap_area_pte(pte, address, end - address, address + phys_addr, flags); | |
62 | address = (address + PMD_SIZE) & PMD_MASK; | |
63 | pmd++; | |
64 | } while (address && (address < end)); | |
65 | return 0; | |
66 | } | |
67 | ||
68 | static int remap_area_pages(unsigned long address, phys_t phys_addr, | |
69 | phys_t size, unsigned long flags) | |
70 | { | |
71 | int error; | |
72 | pgd_t * dir; | |
73 | unsigned long end = address + size; | |
74 | ||
75 | phys_addr -= address; | |
76 | dir = pgd_offset(&init_mm, address); | |
77 | flush_cache_all(); | |
78 | if (address >= end) | |
79 | BUG(); | |
80 | spin_lock(&init_mm.page_table_lock); | |
81 | do { | |
82 | pmd_t *pmd; | |
83 | pmd = pmd_alloc(&init_mm, dir, address); | |
84 | error = -ENOMEM; | |
85 | if (!pmd) | |
86 | break; | |
87 | if (remap_area_pmd(pmd, address, end - address, | |
88 | phys_addr + address, flags)) | |
89 | break; | |
90 | error = 0; | |
91 | address = (address + PGDIR_SIZE) & PGDIR_MASK; | |
92 | dir++; | |
93 | } while (address && (address < end)); | |
94 | spin_unlock(&init_mm.page_table_lock); | |
95 | flush_tlb_all(); | |
96 | return error; | |
97 | } | |
98 | ||
99 | /* | |
100 | * Allow physical addresses to be fixed up to help 36 bit peripherals. | |
101 | */ | |
102 | phys_t __attribute__ ((weak)) | |
103 | fixup_bigphys_addr(phys_t phys_addr, phys_t size) | |
104 | { | |
105 | return phys_addr; | |
106 | } | |
107 | ||
108 | /* | |
109 | * Generic mapping function (not visible outside): | |
110 | */ | |
111 | ||
112 | /* | |
113 | * Remap an arbitrary physical address space into the kernel virtual | |
114 | * address space. Needed when the kernel wants to access high addresses | |
115 | * directly. | |
116 | * | |
117 | * NOTE! We need to allow non-page-aligned mappings too: we will obviously | |
118 | * have to convert them into an offset in a page-aligned mapping, but the | |
119 | * caller shouldn't need to know that small detail. | |
120 | */ | |
121 | ||
122 | #define IS_LOW512(addr) (!((phys_t)(addr) & (phys_t) ~0x1fffffffULL)) | |
123 | ||
124 | void * __ioremap(phys_t phys_addr, phys_t size, unsigned long flags) | |
125 | { | |
126 | struct vm_struct * area; | |
127 | unsigned long offset; | |
128 | phys_t last_addr; | |
129 | void * addr; | |
130 | ||
131 | phys_addr = fixup_bigphys_addr(phys_addr, size); | |
132 | ||
133 | /* Don't allow wraparound or zero size */ | |
134 | last_addr = phys_addr + size - 1; | |
135 | if (!size || last_addr < phys_addr) | |
136 | return NULL; | |
137 | ||
138 | /* | |
139 | * Map uncached objects in the low 512mb of address space using KSEG1, | |
140 | * otherwise map using page tables. | |
141 | */ | |
142 | if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) && | |
143 | flags == _CACHE_UNCACHED) | |
144 | return (void *) KSEG1ADDR(phys_addr); | |
145 | ||
146 | /* | |
147 | * Don't allow anybody to remap normal RAM that we're using.. | |
148 | */ | |
149 | if (phys_addr < virt_to_phys(high_memory)) { | |
150 | char *t_addr, *t_end; | |
151 | struct page *page; | |
152 | ||
153 | t_addr = __va(phys_addr); | |
154 | t_end = t_addr + (size - 1); | |
155 | ||
156 | for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++) | |
157 | if(!PageReserved(page)) | |
158 | return NULL; | |
159 | } | |
160 | ||
161 | /* | |
162 | * Mappings have to be page-aligned | |
163 | */ | |
164 | offset = phys_addr & ~PAGE_MASK; | |
165 | phys_addr &= PAGE_MASK; | |
166 | size = PAGE_ALIGN(last_addr + 1) - phys_addr; | |
167 | ||
168 | /* | |
169 | * Ok, go for it.. | |
170 | */ | |
171 | area = get_vm_area(size, VM_IOREMAP); | |
172 | if (!area) | |
173 | return NULL; | |
174 | addr = area->addr; | |
175 | if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) { | |
176 | vunmap(addr); | |
177 | return NULL; | |
178 | } | |
179 | ||
180 | return (void *) (offset + (char *)addr); | |
181 | } | |
182 | ||
183 | #define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == KSEG1) | |
184 | ||
185 | void __iounmap(volatile void __iomem *addr) | |
186 | { | |
187 | struct vm_struct *p; | |
188 | ||
189 | if (IS_KSEG1(addr)) | |
190 | return; | |
191 | ||
192 | p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr)); | |
193 | if (!p) { | |
194 | printk(KERN_ERR "iounmap: bad address %p\n", addr); | |
195 | return; | |
196 | } | |
197 | ||
198 | kfree(p); | |
199 | } | |
200 | ||
201 | EXPORT_SYMBOL(__ioremap); | |
202 | EXPORT_SYMBOL(__iounmap); |