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6b8baec4 LFT |
1 | /* |
2 | * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch> | |
3 | * Copyright (C) 2009 Wind River Systems Inc | |
4 | * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com | |
5 | * Copyright (C) 2004 Microtronix Datacom Ltd. | |
6 | * | |
7 | * This file is subject to the terms and conditions of the GNU General Public | |
8 | * License. See the file "COPYING" in the main directory of this archive | |
9 | * for more details. | |
10 | */ | |
11 | ||
12 | #include <linux/export.h> | |
13 | #include <linux/sched.h> | |
14 | #include <linux/mm.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/vmalloc.h> | |
17 | #include <linux/io.h> | |
18 | ||
19 | #include <asm/cacheflush.h> | |
20 | #include <asm/tlbflush.h> | |
21 | ||
22 | static inline void remap_area_pte(pte_t *pte, unsigned long address, | |
23 | unsigned long size, unsigned long phys_addr, | |
24 | unsigned long flags) | |
25 | { | |
26 | unsigned long end; | |
27 | unsigned long pfn; | |
28 | pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | _PAGE_READ | |
29 | | _PAGE_WRITE | flags); | |
30 | ||
31 | address &= ~PMD_MASK; | |
32 | end = address + size; | |
33 | if (end > PMD_SIZE) | |
34 | end = PMD_SIZE; | |
35 | if (address >= end) | |
36 | BUG(); | |
37 | pfn = PFN_DOWN(phys_addr); | |
38 | do { | |
39 | if (!pte_none(*pte)) { | |
40 | pr_err("remap_area_pte: page already exists\n"); | |
41 | BUG(); | |
42 | } | |
43 | set_pte(pte, pfn_pte(pfn, pgprot)); | |
44 | address += PAGE_SIZE; | |
45 | pfn++; | |
46 | pte++; | |
47 | } while (address && (address < end)); | |
48 | } | |
49 | ||
50 | static inline int remap_area_pmd(pmd_t *pmd, unsigned long address, | |
51 | unsigned long size, unsigned long phys_addr, | |
52 | unsigned long flags) | |
53 | { | |
54 | unsigned long end; | |
55 | ||
56 | address &= ~PGDIR_MASK; | |
57 | end = address + size; | |
58 | if (end > PGDIR_SIZE) | |
59 | end = PGDIR_SIZE; | |
60 | phys_addr -= address; | |
61 | if (address >= end) | |
62 | BUG(); | |
63 | do { | |
64 | pte_t *pte = pte_alloc_kernel(pmd, address); | |
65 | ||
66 | if (!pte) | |
67 | return -ENOMEM; | |
68 | remap_area_pte(pte, address, end - address, address + phys_addr, | |
69 | flags); | |
70 | address = (address + PMD_SIZE) & PMD_MASK; | |
71 | pmd++; | |
72 | } while (address && (address < end)); | |
73 | return 0; | |
74 | } | |
75 | ||
76 | static int remap_area_pages(unsigned long address, unsigned long phys_addr, | |
77 | unsigned long size, unsigned long flags) | |
78 | { | |
79 | int error; | |
80 | pgd_t *dir; | |
81 | unsigned long end = address + size; | |
82 | ||
83 | phys_addr -= address; | |
84 | dir = pgd_offset(&init_mm, address); | |
85 | flush_cache_all(); | |
86 | if (address >= end) | |
87 | BUG(); | |
88 | do { | |
89 | pud_t *pud; | |
90 | pmd_t *pmd; | |
91 | ||
92 | error = -ENOMEM; | |
93 | pud = pud_alloc(&init_mm, dir, address); | |
94 | if (!pud) | |
95 | break; | |
96 | pmd = pmd_alloc(&init_mm, pud, address); | |
97 | if (!pmd) | |
98 | break; | |
99 | if (remap_area_pmd(pmd, address, end - address, | |
100 | phys_addr + address, flags)) | |
101 | break; | |
102 | error = 0; | |
103 | address = (address + PGDIR_SIZE) & PGDIR_MASK; | |
104 | dir++; | |
105 | } while (address && (address < end)); | |
106 | flush_tlb_all(); | |
107 | return error; | |
108 | } | |
109 | ||
110 | #define IS_MAPPABLE_UNCACHEABLE(addr) (addr < 0x20000000UL) | |
111 | ||
112 | /* | |
113 | * Map some physical address range into the kernel address space. | |
114 | */ | |
5ace77e0 | 115 | void __iomem *ioremap(unsigned long phys_addr, unsigned long size) |
6b8baec4 LFT |
116 | { |
117 | struct vm_struct *area; | |
118 | unsigned long offset; | |
119 | unsigned long last_addr; | |
120 | void *addr; | |
121 | ||
122 | /* Don't allow wraparound or zero size */ | |
123 | last_addr = phys_addr + size - 1; | |
124 | ||
125 | if (!size || last_addr < phys_addr) | |
126 | return NULL; | |
127 | ||
128 | /* Don't allow anybody to remap normal RAM that we're using */ | |
129 | if (phys_addr > PHYS_OFFSET && phys_addr < virt_to_phys(high_memory)) { | |
130 | char *t_addr, *t_end; | |
131 | struct page *page; | |
132 | ||
133 | t_addr = __va(phys_addr); | |
134 | t_end = t_addr + (size - 1); | |
135 | for (page = virt_to_page(t_addr); | |
136 | page <= virt_to_page(t_end); page++) | |
137 | if (!PageReserved(page)) | |
138 | return NULL; | |
139 | } | |
140 | ||
e32ea127 GR |
141 | /* |
142 | * Map uncached objects in the low part of address space to | |
143 | * CONFIG_NIOS2_IO_REGION_BASE | |
144 | */ | |
145 | if (IS_MAPPABLE_UNCACHEABLE(phys_addr) && | |
146 | IS_MAPPABLE_UNCACHEABLE(last_addr)) | |
147 | return (void __iomem *)(CONFIG_NIOS2_IO_REGION_BASE + phys_addr); | |
148 | ||
6b8baec4 LFT |
149 | /* Mappings have to be page-aligned */ |
150 | offset = phys_addr & ~PAGE_MASK; | |
151 | phys_addr &= PAGE_MASK; | |
152 | size = PAGE_ALIGN(last_addr + 1) - phys_addr; | |
153 | ||
154 | /* Ok, go for it */ | |
155 | area = get_vm_area(size, VM_IOREMAP); | |
156 | if (!area) | |
157 | return NULL; | |
158 | addr = area->addr; | |
5ace77e0 | 159 | if (remap_area_pages((unsigned long) addr, phys_addr, size, 0)) { |
6b8baec4 LFT |
160 | vunmap(addr); |
161 | return NULL; | |
162 | } | |
163 | return (void __iomem *) (offset + (char *)addr); | |
164 | } | |
5ace77e0 | 165 | EXPORT_SYMBOL(ioremap); |
6b8baec4 LFT |
166 | |
167 | /* | |
3f3ded99 | 168 | * iounmap unmaps nearly everything, so be careful |
6b8baec4 LFT |
169 | * it doesn't free currently pointer/page tables anymore but it |
170 | * wasn't used anyway and might be added later. | |
171 | */ | |
3f3ded99 | 172 | void iounmap(void __iomem *addr) |
6b8baec4 LFT |
173 | { |
174 | struct vm_struct *p; | |
175 | ||
176 | if ((unsigned long) addr > CONFIG_NIOS2_IO_REGION_BASE) | |
177 | return; | |
178 | ||
179 | p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr)); | |
180 | if (!p) | |
181 | pr_err("iounmap: bad address %p\n", addr); | |
182 | kfree(p); | |
183 | } | |
3f3ded99 | 184 | EXPORT_SYMBOL(iounmap); |