blob: 536021877df60cced06d2d841818790f2f6d9b54 [file] [log] [blame]
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -07001/*
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
17static 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
36static 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
60static 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
84static 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 */
128void __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}
180EXPORT_SYMBOL(__ioremap);
181
182void __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}
197EXPORT_SYMBOL(__iounmap);