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: *pte)) { |
40 | pr_err("remap_area_pte: page already exists\n" ); |
41 | BUG(); |
42 | } |
43 | set_pte(ptep: pte, pte: pfn_pte(page_nr: 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, size: end - address, phys_addr: 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 | p4d_t *p4d; |
90 | pud_t *pud; |
91 | pmd_t *pmd; |
92 | |
93 | error = -ENOMEM; |
94 | p4d = p4d_alloc(mm: &init_mm, pgd: dir, address); |
95 | if (!p4d) |
96 | break; |
97 | pud = pud_alloc(mm: &init_mm, p4d, address); |
98 | if (!pud) |
99 | break; |
100 | pmd = pmd_alloc(mm: &init_mm, pud, address); |
101 | if (!pmd) |
102 | break; |
103 | if (remap_area_pmd(pmd, address, size: end - address, |
104 | phys_addr: phys_addr + address, flags)) |
105 | break; |
106 | error = 0; |
107 | address = (address + PGDIR_SIZE) & PGDIR_MASK; |
108 | dir++; |
109 | } while (address && (address < end)); |
110 | flush_tlb_all(); |
111 | return error; |
112 | } |
113 | |
114 | #define IS_MAPPABLE_UNCACHEABLE(addr) (addr < 0x20000000UL) |
115 | |
116 | /* |
117 | * Map some physical address range into the kernel address space. |
118 | */ |
119 | void __iomem *ioremap(unsigned long phys_addr, unsigned long size) |
120 | { |
121 | struct vm_struct *area; |
122 | unsigned long offset; |
123 | unsigned long last_addr; |
124 | void *addr; |
125 | |
126 | /* Don't allow wraparound or zero size */ |
127 | last_addr = phys_addr + size - 1; |
128 | |
129 | if (!size || last_addr < phys_addr) |
130 | return NULL; |
131 | |
132 | /* Don't allow anybody to remap normal RAM that we're using */ |
133 | if (phys_addr > PHYS_OFFSET && phys_addr < virt_to_phys(address: high_memory)) { |
134 | char *t_addr, *t_end; |
135 | struct page *page; |
136 | |
137 | t_addr = __va(phys_addr); |
138 | t_end = t_addr + (size - 1); |
139 | for (page = virt_to_page(t_addr); |
140 | page <= virt_to_page(t_end); page++) |
141 | if (!PageReserved(page)) |
142 | return NULL; |
143 | } |
144 | |
145 | /* |
146 | * Map uncached objects in the low part of address space to |
147 | * CONFIG_NIOS2_IO_REGION_BASE |
148 | */ |
149 | if (IS_MAPPABLE_UNCACHEABLE(phys_addr) && |
150 | IS_MAPPABLE_UNCACHEABLE(last_addr)) |
151 | return (void __iomem *)(CONFIG_NIOS2_IO_REGION_BASE + phys_addr); |
152 | |
153 | /* Mappings have to be page-aligned */ |
154 | offset = phys_addr & ~PAGE_MASK; |
155 | phys_addr &= PAGE_MASK; |
156 | size = PAGE_ALIGN(last_addr + 1) - phys_addr; |
157 | |
158 | /* Ok, go for it */ |
159 | area = get_vm_area(size, VM_IOREMAP); |
160 | if (!area) |
161 | return NULL; |
162 | addr = area->addr; |
163 | if (remap_area_pages(address: (unsigned long) addr, phys_addr, size, flags: 0)) { |
164 | vunmap(addr); |
165 | return NULL; |
166 | } |
167 | return (void __iomem *) (offset + (char *)addr); |
168 | } |
169 | EXPORT_SYMBOL(ioremap); |
170 | |
171 | /* |
172 | * iounmap unmaps nearly everything, so be careful |
173 | * it doesn't free currently pointer/page tables anymore but it |
174 | * wasn't used anyway and might be added later. |
175 | */ |
176 | void iounmap(void __iomem *addr) |
177 | { |
178 | struct vm_struct *p; |
179 | |
180 | if ((unsigned long) addr > CONFIG_NIOS2_IO_REGION_BASE) |
181 | return; |
182 | |
183 | p = remove_vm_area(addr: (void *) (PAGE_MASK & (unsigned long __force) addr)); |
184 | if (!p) |
185 | pr_err("iounmap: bad address %p\n" , addr); |
186 | kfree(objp: p); |
187 | } |
188 | EXPORT_SYMBOL(iounmap); |
189 | |