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/export.h>
10 #include <asm/addrspace.h>
11 #include <asm/byteorder.h>
12 #include <linux/ioport.h>
13 #include <linux/sched.h>
14 #include <linux/slab.h>
15 #include <linux/vmalloc.h>
16 #include <linux/mm_types.h>
17 #include <asm/cacheflush.h>
18 #include <asm/io.h>
19 #include <asm/tlbflush.h>
20
remap_area_pte(pte_t * pte,unsigned long address,phys_addr_t size,phys_addr_t phys_addr,unsigned long flags)21 static inline void remap_area_pte(pte_t * pte, unsigned long address,
22 phys_addr_t size, phys_addr_t phys_addr, unsigned long flags)
23 {
24 phys_addr_t end;
25 unsigned long pfn;
26 pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | __READABLE
27 | __WRITEABLE | flags);
28
29 address &= ~PMD_MASK;
30 end = address + size;
31 if (end > PMD_SIZE)
32 end = PMD_SIZE;
33 BUG_ON(address >= end);
34 pfn = phys_addr >> PAGE_SHIFT;
35 do {
36 if (!pte_none(*pte)) {
37 printk("remap_area_pte: page already exists\n");
38 BUG();
39 }
40 set_pte(pte, pfn_pte(pfn, pgprot));
41 address += PAGE_SIZE;
42 pfn++;
43 pte++;
44 } while (address && (address < end));
45 }
46
remap_area_pmd(pmd_t * pmd,unsigned long address,phys_addr_t size,phys_addr_t phys_addr,unsigned long flags)47 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address,
48 phys_addr_t size, phys_addr_t phys_addr, unsigned long flags)
49 {
50 phys_addr_t end;
51
52 address &= ~PGDIR_MASK;
53 end = address + size;
54 if (end > PGDIR_SIZE)
55 end = PGDIR_SIZE;
56 phys_addr -= address;
57 BUG_ON(address >= end);
58 do {
59 pte_t * pte = pte_alloc_kernel(pmd, address);
60 if (!pte)
61 return -ENOMEM;
62 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
63 address = (address + PMD_SIZE) & PMD_MASK;
64 pmd++;
65 } while (address && (address < end));
66 return 0;
67 }
68
remap_area_pages(unsigned long address,phys_addr_t phys_addr,phys_addr_t size,unsigned long flags)69 static int remap_area_pages(unsigned long address, phys_addr_t phys_addr,
70 phys_addr_t size, unsigned long flags)
71 {
72 int error;
73 pgd_t * dir;
74 unsigned long end = address + size;
75
76 phys_addr -= address;
77 dir = pgd_offset(&init_mm, address);
78 flush_cache_all();
79 BUG_ON(address >= end);
80 do {
81 pud_t *pud;
82 pmd_t *pmd;
83
84 error = -ENOMEM;
85 pud = pud_alloc(&init_mm, dir, address);
86 if (!pud)
87 break;
88 pmd = pmd_alloc(&init_mm, pud, address);
89 if (!pmd)
90 break;
91 if (remap_area_pmd(pmd, address, end - address,
92 phys_addr + address, flags))
93 break;
94 error = 0;
95 address = (address + PGDIR_SIZE) & PGDIR_MASK;
96 dir++;
97 } while (address && (address < end));
98 flush_tlb_all();
99 return error;
100 }
101
__ioremap_check_ram(unsigned long start_pfn,unsigned long nr_pages,void * arg)102 static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,
103 void *arg)
104 {
105 unsigned long i;
106
107 for (i = 0; i < nr_pages; i++) {
108 if (pfn_valid(start_pfn + i) &&
109 !PageReserved(pfn_to_page(start_pfn + i)))
110 return 1;
111 }
112
113 return 0;
114 }
115
116 /*
117 * Generic mapping function (not visible outside):
118 */
119
120 /*
121 * Remap an arbitrary physical address space into the kernel virtual
122 * address space. Needed when the kernel wants to access high addresses
123 * directly.
124 *
125 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
126 * have to convert them into an offset in a page-aligned mapping, but the
127 * caller shouldn't need to know that small detail.
128 */
129
130 #define IS_LOW512(addr) (!((phys_addr_t)(addr) & (phys_addr_t) ~0x1fffffffULL))
131
__ioremap(phys_addr_t phys_addr,phys_addr_t size,unsigned long flags)132 void __iomem * __ioremap(phys_addr_t phys_addr, phys_addr_t size, unsigned long flags)
133 {
134 unsigned long offset, pfn, last_pfn;
135 struct vm_struct * area;
136 phys_addr_t last_addr;
137 void * addr;
138
139 phys_addr = fixup_bigphys_addr(phys_addr, size);
140
141 /* Don't allow wraparound or zero size */
142 last_addr = phys_addr + size - 1;
143 if (!size || last_addr < phys_addr)
144 return NULL;
145
146 /*
147 * Map uncached objects in the low 512mb of address space using KSEG1,
148 * otherwise map using page tables.
149 */
150 if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) &&
151 flags == _CACHE_UNCACHED)
152 return (void __iomem *) CKSEG1ADDR(phys_addr);
153
154 /*
155 * Don't allow anybody to remap RAM that may be allocated by the page
156 * allocator, since that could lead to races & data clobbering.
157 */
158 pfn = PFN_DOWN(phys_addr);
159 last_pfn = PFN_DOWN(last_addr);
160 if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
161 __ioremap_check_ram) == 1) {
162 WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n",
163 &phys_addr, &last_addr);
164 return NULL;
165 }
166
167 /*
168 * Mappings have to be page-aligned
169 */
170 offset = phys_addr & ~PAGE_MASK;
171 phys_addr &= PAGE_MASK;
172 size = PAGE_ALIGN(last_addr + 1) - phys_addr;
173
174 /*
175 * Ok, go for it..
176 */
177 area = get_vm_area(size, VM_IOREMAP);
178 if (!area)
179 return NULL;
180 addr = area->addr;
181 if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
182 vunmap(addr);
183 return NULL;
184 }
185
186 return (void __iomem *) (offset + (char *)addr);
187 }
188
189 #define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
190
__iounmap(const volatile void __iomem * addr)191 void __iounmap(const volatile void __iomem *addr)
192 {
193 struct vm_struct *p;
194
195 if (IS_KSEG1(addr))
196 return;
197
198 p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));
199 if (!p)
200 printk(KERN_ERR "iounmap: bad address %p\n", addr);
201
202 kfree(p);
203 }
204
205 EXPORT_SYMBOL(__ioremap);
206 EXPORT_SYMBOL(__iounmap);
207
