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1da177e4 LT |
1 | /* |
2 | * linux/arch/arm/mm/ioremap.c | |
3 | * | |
4 | * Re-map IO memory to kernel address space so that we can access it. | |
5 | * | |
6 | * (C) Copyright 1995 1996 Linus Torvalds | |
7 | * | |
8 | * Hacked for ARM by Phil Blundell <philb@gnu.org> | |
9 | * Hacked to allow all architectures to build, and various cleanups | |
10 | * by Russell King | |
11 | * | |
12 | * This allows a driver to remap an arbitrary region of bus memory into | |
13 | * virtual space. One should *only* use readl, writel, memcpy_toio and | |
14 | * so on with such remapped areas. | |
15 | * | |
16 | * Because the ARM only has a 32-bit address space we can't address the | |
17 | * whole of the (physical) PCI space at once. PCI huge-mode addressing | |
18 | * allows us to circumvent this restriction by splitting PCI space into | |
19 | * two 2GB chunks and mapping only one at a time into processor memory. | |
20 | * We use MMU protection domains to trap any attempt to access the bank | |
21 | * that is not currently mapped. (This isn't fully implemented yet.) | |
22 | */ | |
23 | #include <linux/module.h> | |
24 | #include <linux/errno.h> | |
25 | #include <linux/mm.h> | |
26 | #include <linux/vmalloc.h> | |
27 | ||
28 | #include <asm/cacheflush.h> | |
29 | #include <asm/io.h> | |
30 | #include <asm/tlbflush.h> | |
31 | ||
32 | static inline void | |
33 | remap_area_pte(pte_t * pte, unsigned long address, unsigned long size, | |
34 | unsigned long phys_addr, pgprot_t pgprot) | |
35 | { | |
36 | unsigned long end; | |
37 | ||
38 | address &= ~PMD_MASK; | |
39 | end = address + size; | |
40 | if (end > PMD_SIZE) | |
41 | end = PMD_SIZE; | |
42 | BUG_ON(address >= end); | |
43 | do { | |
44 | if (!pte_none(*pte)) | |
45 | goto bad; | |
46 | ||
47 | set_pte(pte, pfn_pte(phys_addr >> PAGE_SHIFT, pgprot)); | |
48 | address += PAGE_SIZE; | |
49 | phys_addr += PAGE_SIZE; | |
50 | pte++; | |
51 | } while (address && (address < end)); | |
52 | return; | |
53 | ||
54 | bad: | |
55 | printk("remap_area_pte: page already exists\n"); | |
56 | BUG(); | |
57 | } | |
58 | ||
59 | static inline int | |
60 | remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size, | |
61 | unsigned long phys_addr, unsigned long flags) | |
62 | { | |
63 | unsigned long end; | |
64 | pgprot_t pgprot; | |
65 | ||
66 | address &= ~PGDIR_MASK; | |
67 | end = address + size; | |
68 | ||
69 | if (end > PGDIR_SIZE) | |
70 | end = PGDIR_SIZE; | |
71 | ||
72 | phys_addr -= address; | |
73 | BUG_ON(address >= end); | |
74 | ||
75 | pgprot = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY | L_PTE_WRITE | flags); | |
76 | do { | |
77 | pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address); | |
78 | if (!pte) | |
79 | return -ENOMEM; | |
80 | remap_area_pte(pte, address, end - address, address + phys_addr, pgprot); | |
81 | address = (address + PMD_SIZE) & PMD_MASK; | |
82 | pmd++; | |
83 | } while (address && (address < end)); | |
84 | return 0; | |
85 | } | |
86 | ||
87 | static int | |
88 | remap_area_pages(unsigned long start, unsigned long phys_addr, | |
89 | unsigned long size, unsigned long flags) | |
90 | { | |
91 | unsigned long address = start; | |
92 | unsigned long end = start + size; | |
93 | int err = 0; | |
94 | pgd_t * dir; | |
95 | ||
96 | phys_addr -= address; | |
97 | dir = pgd_offset(&init_mm, address); | |
98 | BUG_ON(address >= end); | |
99 | spin_lock(&init_mm.page_table_lock); | |
100 | do { | |
101 | pmd_t *pmd = pmd_alloc(&init_mm, dir, address); | |
102 | if (!pmd) { | |
103 | err = -ENOMEM; | |
104 | break; | |
105 | } | |
106 | if (remap_area_pmd(pmd, address, end - address, | |
107 | phys_addr + address, flags)) { | |
108 | err = -ENOMEM; | |
109 | break; | |
110 | } | |
111 | ||
112 | address = (address + PGDIR_SIZE) & PGDIR_MASK; | |
113 | dir++; | |
114 | } while (address && (address < end)); | |
115 | ||
116 | spin_unlock(&init_mm.page_table_lock); | |
117 | flush_cache_vmap(start, end); | |
118 | return err; | |
119 | } | |
120 | ||
121 | /* | |
122 | * Remap an arbitrary physical address space into the kernel virtual | |
123 | * address space. Needed when the kernel wants to access high addresses | |
124 | * directly. | |
125 | * | |
126 | * NOTE! We need to allow non-page-aligned mappings too: we will obviously | |
127 | * have to convert them into an offset in a page-aligned mapping, but the | |
128 | * caller shouldn't need to know that small detail. | |
129 | * | |
130 | * 'flags' are the extra L_PTE_ flags that you want to specify for this | |
131 | * mapping. See include/asm-arm/proc-armv/pgtable.h for more information. | |
132 | */ | |
133 | void __iomem * | |
134 | __ioremap(unsigned long phys_addr, size_t size, unsigned long flags, | |
135 | unsigned long align) | |
136 | { | |
137 | void * addr; | |
138 | struct vm_struct * area; | |
139 | unsigned long offset, last_addr; | |
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 | * Mappings have to be page-aligned | |
148 | */ | |
149 | offset = phys_addr & ~PAGE_MASK; | |
150 | phys_addr &= PAGE_MASK; | |
151 | size = PAGE_ALIGN(last_addr + 1) - phys_addr; | |
152 | ||
153 | /* | |
154 | * Ok, go for it.. | |
155 | */ | |
156 | area = get_vm_area(size, VM_IOREMAP); | |
157 | if (!area) | |
158 | return NULL; | |
159 | addr = area->addr; | |
160 | if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) { | |
161 | vfree(addr); | |
162 | return NULL; | |
163 | } | |
164 | return (void __iomem *) (offset + (char *)addr); | |
165 | } | |
166 | EXPORT_SYMBOL(__ioremap); | |
167 | ||
168 | void __iounmap(void __iomem *addr) | |
169 | { | |
170 | vfree((void *) (PAGE_MASK & (unsigned long) addr)); | |
171 | } | |
172 | EXPORT_SYMBOL(__iounmap); | |
09f0551d RK |
173 | |
174 | #ifdef __io | |
175 | void __iomem *ioport_map(unsigned long port, unsigned int nr) | |
176 | { | |
177 | return __io(port); | |
178 | } | |
179 | EXPORT_SYMBOL(ioport_map); | |
180 | ||
181 | void ioport_unmap(void __iomem *addr) | |
182 | { | |
183 | } | |
184 | EXPORT_SYMBOL(ioport_unmap); | |
185 | #endif | |
186 | ||
187 | #ifdef CONFIG_PCI | |
188 | #include <linux/pci.h> | |
189 | #include <linux/ioport.h> | |
190 | ||
191 | void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen) | |
192 | { | |
193 | unsigned long start = pci_resource_start(dev, bar); | |
194 | unsigned long len = pci_resource_len(dev, bar); | |
195 | unsigned long flags = pci_resource_flags(dev, bar); | |
196 | ||
197 | if (!len || !start) | |
198 | return NULL; | |
199 | if (maxlen && len > maxlen) | |
200 | len = maxlen; | |
201 | if (flags & IORESOURCE_IO) | |
202 | return ioport_map(start, len); | |
203 | if (flags & IORESOURCE_MEM) { | |
204 | if (flags & IORESOURCE_CACHEABLE) | |
205 | return ioremap(start, len); | |
206 | return ioremap_nocache(start, len); | |
207 | } | |
208 | return NULL; | |
209 | } | |
210 | EXPORT_SYMBOL(pci_iomap); | |
211 | ||
212 | void pci_iounmap(struct pci_dev *dev, void __iomem *addr) | |
213 | { | |
214 | if ((unsigned long)addr >= VMALLOC_START && | |
215 | (unsigned long)addr < VMALLOC_END) | |
216 | iounmap(addr); | |
217 | } | |
218 | EXPORT_SYMBOL(pci_iounmap); | |
219 | #endif |