LXR linux/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
  17static int __read_mostly ioremap_pud_capable;
  18static int __read_mostly ioremap_pmd_capable;
  19static int __read_mostly ioremap_huge_disabled;
  20
  21static int __init set_nohugeiomap(char *str)
  22{
  23        ioremap_huge_disabled = 1;
  24        return 0;
  25}
  26early_param("nohugeiomap", set_nohugeiomap);
  27
  28void __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
  38static inline int ioremap_pud_enabled(void)
  39{
  40        return ioremap_pud_capable;
  41}
  42
  43static inline int ioremap_pmd_enabled(void)
  44{
  45        return ioremap_pmd_capable;
  46}
  47
  48#else   /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
  49static inline int ioremap_pud_enabled(void) { return 0; }
  50static inline int ioremap_pmd_enabled(void) { return 0; }
  51#endif  /* CONFIG_HAVE_ARCH_HUGE_VMAP */
  52
  53static 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
  71static 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
  97static 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
 123int 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}
 147EXPORT_SYMBOL_GPL(ioremap_page_range);
 148