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[kvmfornfv.git] / kernel / lib / ioremap.c
1 /*
2  * Re-map IO memory to kernel address space so that we can access it.
3  * This is needed for high PCI addresses that aren't mapped in the
4  * 640k-1MB IO memory area on PC's
5  *
6  * (C) Copyright 1995 1996 Linus Torvalds
7  */
8 #include <linux/vmalloc.h>
9 #include <linux/mm.h>
10 #include <linux/sched.h>
11 #include <linux/io.h>
12 #include <linux/export.h>
13 #include <asm/cacheflush.h>
14 #include <asm/pgtable.h>
15
16 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
17 static int __read_mostly ioremap_pud_capable;
18 static int __read_mostly ioremap_pmd_capable;
19 static int __read_mostly ioremap_huge_disabled;
20
21 static int __init set_nohugeiomap(char *str)
22 {
23         ioremap_huge_disabled = 1;
24         return 0;
25 }
26 early_param("nohugeiomap", set_nohugeiomap);
27
28 void __init ioremap_huge_init(void)
29 {
30         if (!ioremap_huge_disabled) {
31                 if (arch_ioremap_pud_supported())
32                         ioremap_pud_capable = 1;
33                 if (arch_ioremap_pmd_supported())
34                         ioremap_pmd_capable = 1;
35         }
36 }
37
38 static inline int ioremap_pud_enabled(void)
39 {
40         return ioremap_pud_capable;
41 }
42
43 static inline int ioremap_pmd_enabled(void)
44 {
45         return ioremap_pmd_capable;
46 }
47
48 #else   /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
49 static inline int ioremap_pud_enabled(void) { return 0; }
50 static inline int ioremap_pmd_enabled(void) { return 0; }
51 #endif  /* CONFIG_HAVE_ARCH_HUGE_VMAP */
52
53 static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
54                 unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
55 {
56         pte_t *pte;
57         u64 pfn;
58
59         pfn = phys_addr >> PAGE_SHIFT;
60         pte = pte_alloc_kernel(pmd, addr);
61         if (!pte)
62                 return -ENOMEM;
63         do {
64                 BUG_ON(!pte_none(*pte));
65                 set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
66                 pfn++;
67         } while (pte++, addr += PAGE_SIZE, addr != end);
68         return 0;
69 }
70
71 static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
72                 unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
73 {
74         pmd_t *pmd;
75         unsigned long next;
76
77         phys_addr -= addr;
78         pmd = pmd_alloc(&init_mm, pud, addr);
79         if (!pmd)
80                 return -ENOMEM;
81         do {
82                 next = pmd_addr_end(addr, end);
83
84                 if (ioremap_pmd_enabled() &&
85                     ((next - addr) == PMD_SIZE) &&
86                     IS_ALIGNED(phys_addr + addr, PMD_SIZE)) {
87                         if (pmd_set_huge(pmd, phys_addr + addr, prot))
88                                 continue;
89                 }
90
91                 if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot))
92                         return -ENOMEM;
93         } while (pmd++, addr = next, addr != end);
94         return 0;
95 }
96
97 static inline int ioremap_pud_range(pgd_t *pgd, unsigned long addr,
98                 unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
99 {
100         pud_t *pud;
101         unsigned long next;
102
103         phys_addr -= addr;
104         pud = pud_alloc(&init_mm, pgd, addr);
105         if (!pud)
106                 return -ENOMEM;
107         do {
108                 next = pud_addr_end(addr, end);
109
110                 if (ioremap_pud_enabled() &&
111                     ((next - addr) == PUD_SIZE) &&
112                     IS_ALIGNED(phys_addr + addr, PUD_SIZE)) {
113                         if (pud_set_huge(pud, phys_addr + addr, prot))
114                                 continue;
115                 }
116
117                 if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot))
118                         return -ENOMEM;
119         } while (pud++, addr = next, addr != end);
120         return 0;
121 }
122
123 int ioremap_page_range(unsigned long addr,
124                        unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
125 {
126         pgd_t *pgd;
127         unsigned long start;
128         unsigned long next;
129         int err;
130
131         BUG_ON(addr >= end);
132
133         start = addr;
134         phys_addr -= addr;
135         pgd = pgd_offset_k(addr);
136         do {
137                 next = pgd_addr_end(addr, end);
138                 err = ioremap_pud_range(pgd, addr, next, phys_addr+addr, prot);
139                 if (err)
140                         break;
141         } while (pgd++, addr = next, addr != end);
142
143         flush_cache_vmap(start, end);
144
145         return err;
146 }
147 EXPORT_SYMBOL_GPL(ioremap_page_range);