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61e85e36 JB |
1 | /* |
2 | * OpenRISC ioremap.c | |
3 | * | |
4 | * Linux architectural port borrowing liberally from similar works of | |
5 | * others. All original copyrights apply as per the original source | |
6 | * declaration. | |
7 | * | |
8 | * Modifications for the OpenRISC architecture: | |
9 | * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> | |
10 | * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or | |
13 | * modify it under the terms of the GNU General Public License | |
14 | * as published by the Free Software Foundation; either version | |
15 | * 2 of the License, or (at your option) any later version. | |
16 | */ | |
17 | ||
18 | #include <linux/vmalloc.h> | |
19 | #include <linux/io.h> | |
20 | #include <asm/pgalloc.h> | |
21 | #include <asm/kmap_types.h> | |
22 | #include <asm/fixmap.h> | |
23 | #include <asm/bug.h> | |
24 | #include <asm/pgtable.h> | |
25 | #include <linux/sched.h> | |
26 | #include <asm/tlbflush.h> | |
27 | ||
28 | extern int mem_init_done; | |
29 | ||
30 | static unsigned int fixmaps_used __initdata; | |
31 | ||
32 | /* | |
33 | * Remap an arbitrary physical address space into the kernel virtual | |
34 | * address space. Needed when the kernel wants to access high addresses | |
35 | * directly. | |
36 | * | |
37 | * NOTE! We need to allow non-page-aligned mappings too: we will obviously | |
38 | * have to convert them into an offset in a page-aligned mapping, but the | |
39 | * caller shouldn't need to know that small detail. | |
40 | */ | |
41 | void __iomem *__init_refok | |
42 | __ioremap(phys_addr_t addr, unsigned long size, pgprot_t prot) | |
43 | { | |
44 | phys_addr_t p; | |
45 | unsigned long v; | |
46 | unsigned long offset, last_addr; | |
47 | struct vm_struct *area = NULL; | |
48 | ||
49 | /* Don't allow wraparound or zero size */ | |
50 | last_addr = addr + size - 1; | |
51 | if (!size || last_addr < addr) | |
52 | return NULL; | |
53 | ||
54 | /* | |
55 | * Mappings have to be page-aligned | |
56 | */ | |
57 | offset = addr & ~PAGE_MASK; | |
58 | p = addr & PAGE_MASK; | |
59 | size = PAGE_ALIGN(last_addr + 1) - p; | |
60 | ||
61 | if (likely(mem_init_done)) { | |
62 | area = get_vm_area(size, VM_IOREMAP); | |
63 | if (!area) | |
64 | return NULL; | |
65 | v = (unsigned long)area->addr; | |
66 | } else { | |
67 | if ((fixmaps_used + (size >> PAGE_SHIFT)) > FIX_N_IOREMAPS) | |
68 | return NULL; | |
69 | v = fix_to_virt(FIX_IOREMAP_BEGIN + fixmaps_used); | |
70 | fixmaps_used += (size >> PAGE_SHIFT); | |
71 | } | |
72 | ||
73 | if (ioremap_page_range(v, v + size, p, prot)) { | |
74 | if (likely(mem_init_done)) | |
75 | vfree(area->addr); | |
76 | else | |
77 | fixmaps_used -= (size >> PAGE_SHIFT); | |
78 | return NULL; | |
79 | } | |
80 | ||
81 | return (void __iomem *)(offset + (char *)v); | |
82 | } | |
83 | ||
84 | void iounmap(void *addr) | |
85 | { | |
86 | /* If the page is from the fixmap pool then we just clear out | |
87 | * the fixmap mapping. | |
88 | */ | |
89 | if (unlikely((unsigned long)addr > FIXADDR_START)) { | |
90 | /* This is a bit broken... we don't really know | |
91 | * how big the area is so it's difficult to know | |
92 | * how many fixed pages to invalidate... | |
93 | * just flush tlb and hope for the best... | |
94 | * consider this a FIXME | |
95 | * | |
96 | * Really we should be clearing out one or more page | |
97 | * table entries for these virtual addresses so that | |
98 | * future references cause a page fault... for now, we | |
99 | * rely on two things: | |
100 | * i) this code never gets called on known boards | |
101 | * ii) invalid accesses to the freed areas aren't made | |
102 | */ | |
103 | flush_tlb_all(); | |
104 | return; | |
105 | } | |
106 | ||
107 | return vfree((void *)(PAGE_MASK & (unsigned long)addr)); | |
108 | } | |
109 | ||
110 | /** | |
111 | * OK, this one's a bit tricky... ioremap can get called before memory is | |
112 | * initialized (early serial console does this) and will want to alloc a page | |
113 | * for its mapping. No userspace pages will ever get allocated before memory | |
114 | * is initialized so this applies only to kernel pages. In the event that | |
115 | * this is called before memory is initialized we allocate the page using | |
116 | * the memblock infrastructure. | |
117 | */ | |
118 | ||
119 | pte_t __init_refok *pte_alloc_one_kernel(struct mm_struct *mm, | |
120 | unsigned long address) | |
121 | { | |
122 | pte_t *pte; | |
123 | ||
124 | if (likely(mem_init_done)) { | |
125 | pte = (pte_t *) __get_free_page(GFP_KERNEL | __GFP_REPEAT); | |
126 | } else { | |
127 | pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE); | |
128 | #if 0 | |
129 | /* FIXME: use memblock... */ | |
130 | pte = (pte_t *) __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE)); | |
131 | #endif | |
132 | } | |
133 | ||
134 | if (pte) | |
135 | clear_page(pte); | |
136 | return pte; | |
137 | } |