aboutsummaryrefslogtreecommitdiffstats
path: root/arch/mips/mm/ioremap.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/mips/mm/ioremap.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/mips/mm/ioremap.c')
-rw-r--r--arch/mips/mm/ioremap.c202
1 files changed, 202 insertions, 0 deletions
diff --git a/arch/mips/mm/ioremap.c b/arch/mips/mm/ioremap.c
new file mode 100644
index 000000000000..adf352273f63
--- /dev/null
+++ b/arch/mips/mm/ioremap.c
@@ -0,0 +1,202 @@
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
18static 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
45static 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
68static 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 */
102phys_t __attribute__ ((weak))
103fixup_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
124void * __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
185void __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
201EXPORT_SYMBOL(__ioremap);
202EXPORT_SYMBOL(__iounmap);