Root/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 <asm/cacheflush.h>
13#include <asm/pgtable.h>
14
15static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
16        unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
17{
18    pte_t *pte;
19    u64 pfn;
20
21    pfn = phys_addr >> PAGE_SHIFT;
22    pte = pte_alloc_kernel(pmd, addr);
23    if (!pte)
24        return -ENOMEM;
25    do {
26        BUG_ON(!pte_none(*pte));
27        set_pte_at(&init_mm, addr, pte, pfn_pte(pfn, prot));
28        pfn++;
29    } while (pte++, addr += PAGE_SIZE, addr != end);
30    return 0;
31}
32
33static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
34        unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
35{
36    pmd_t *pmd;
37    unsigned long next;
38
39    phys_addr -= addr;
40    pmd = pmd_alloc(&init_mm, pud, addr);
41    if (!pmd)
42        return -ENOMEM;
43    do {
44        next = pmd_addr_end(addr, end);
45        if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot))
46            return -ENOMEM;
47    } while (pmd++, addr = next, addr != end);
48    return 0;
49}
50
51static inline int ioremap_pud_range(pgd_t *pgd, unsigned long addr,
52        unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
53{
54    pud_t *pud;
55    unsigned long next;
56
57    phys_addr -= addr;
58    pud = pud_alloc(&init_mm, pgd, addr);
59    if (!pud)
60        return -ENOMEM;
61    do {
62        next = pud_addr_end(addr, end);
63        if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot))
64            return -ENOMEM;
65    } while (pud++, addr = next, addr != end);
66    return 0;
67}
68
69int ioremap_page_range(unsigned long addr,
70               unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
71{
72    pgd_t *pgd;
73    unsigned long start;
74    unsigned long next;
75    int err;
76
77    BUG_ON(addr >= end);
78
79    start = addr;
80    phys_addr -= addr;
81    pgd = pgd_offset_k(addr);
82    do {
83        next = pgd_addr_end(addr, end);
84        err = ioremap_pud_range(pgd, addr, next, phys_addr+addr, prot);
85        if (err)
86            break;
87    } while (pgd++, addr = next, addr != end);
88
89    flush_cache_vmap(start, end);
90
91    return err;
92}
93

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