arch/avr32/mm/ioremap.c

   1 /*
   2  * Copyright (C) 2004-2006 Atmel Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8 #include <linux/vmalloc.h>
   9 #include <linux/module.h>
  10
  11 #include <asm/io.h>
  12 #include <asm/pgtable.h>
  13 #include <asm/cacheflush.h>
  14 #include <asm/tlbflush.h>
  15 #include <asm/addrspace.h>
  16
  17 static inline int remap_area_pte(pte_t *pte, unsigned long address,
  18                                   unsigned long end, unsigned long phys_addr,
  19                                   pgprot_t prot)
  20 {
  21         unsigned long pfn;
  22
  23         pfn = phys_addr >> PAGE_SHIFT;
  24         do {
  25                 WARN_ON(!pte_none(*pte));
  26
  27                 set_pte(pte, pfn_pte(pfn, prot));
  28                 address += PAGE_SIZE;
  29                 pfn++;
  30                 pte++;
  31         } while (address && (address < end));
  32
  33         return 0;
  34 }
  35
  36 static inline int remap_area_pmd(pmd_t *pmd, unsigned long address,
  37                                  unsigned long end, unsigned long phys_addr,
  38                                  pgprot_t prot)
  39 {
  40         unsigned long next;
  41
  42         phys_addr -= address;
  43
  44         do {
  45                 pte_t *pte = pte_alloc_kernel(pmd, address);
  46                 if (!pte)
  47                         return -ENOMEM;
  48
  49                 next = (address + PMD_SIZE) & PMD_MASK;
  50                 if (remap_area_pte(pte, address, next,
  51                                    address + phys_addr, prot))
  52                         return -ENOMEM;
  53
  54                 address = next;
  55                 pmd++;
  56         } while (address && (address < end));
  57         return 0;
  58 }
  59
  60 static int remap_area_pud(pud_t *pud, unsigned long address,
  61                           unsigned long end, unsigned long phys_addr,
  62                           pgprot_t prot)
  63 {
  64         unsigned long next;
  65
  66         phys_addr -= address;
  67
  68         do {
  69                 pmd_t *pmd = pmd_alloc(&init_mm, pud, address);
  70                 if (!pmd)
  71                         return -ENOMEM;
  72                 next = (address + PUD_SIZE) & PUD_MASK;
  73                 if (remap_area_pmd(pmd, address, next,
  74                                    phys_addr + address, prot))
  75                         return -ENOMEM;
  76
  77                 address = next;
  78                 pud++;
  79         } while (address && address < end);
  80
  81         return 0;
  82 }
  83
  84 static int remap_area_pages(unsigned long address, unsigned long phys_addr,
  85                             size_t size, pgprot_t prot)
  86 {
  87         unsigned long end = address + size;
  88         unsigned long next;
  89         pgd_t *pgd;
  90         int err = 0;
  91
  92         phys_addr -= address;
  93
  94         pgd = pgd_offset_k(address);
  95         flush_cache_all();
  96         BUG_ON(address >= end);
  97
  98         spin_lock(&init_mm.page_table_lock);
  99         do {
 100                 pud_t *pud = pud_alloc(&init_mm, pgd, address);
 101
 102                 err = -ENOMEM;
 103                 if (!pud)
 104                         break;
 105
 106                 next = (address + PGDIR_SIZE) & PGDIR_MASK;
 107                 if (next < address || next > end)
 108                         next = end;
 109                 err = remap_area_pud(pud, address, next,
 110                                      phys_addr + address, prot);
 111                 if (err)
 112                         break;
 113
 114                 address = next;
 115                 pgd++;
 116         } while (address && (address < end));
 117
 118         spin_unlock(&init_mm.page_table_lock);
 119         flush_tlb_all();
 120         return err;
 121 }
 122
 123 /*
 124  * Re-map an arbitrary physical address space into the kernel virtual
 125  * address space. Needed when the kernel wants to access physical
 126  * memory directly.
 127  */
 128 void __iomem *__ioremap(unsigned long phys_addr, size_t size,
 129                         unsigned long flags)
 130 {
 131         void *addr;
 132         struct vm_struct *area;
 133         unsigned long offset, last_addr;
 134         pgprot_t prot;
 135
 136         /*
 137          * Check if we can simply use the P4 segment. This area is
 138          * uncacheable, so if caching/buffering is requested, we can't
 139          * use it.
 140          */
 141         if ((phys_addr >= P4SEG) && (flags == 0))
 142                 return (void __iomem *)phys_addr;
 143
 144         /* Don't allow wraparound or zero size */
 145         last_addr = phys_addr + size - 1;
 146         if (!size || last_addr < phys_addr)
 147                 return NULL;
 148
 149         /*
 150          * XXX: When mapping regular RAM, we'd better make damn sure
 151          * it's never used for anything else.  But this is really the
 152          * caller's responsibility...
 153          */
 154         if (PHYSADDR(P2SEGADDR(phys_addr)) == phys_addr)
 155                 return (void __iomem *)P2SEGADDR(phys_addr);
 156
 157         /* Mappings have to be page-aligned */
 158         offset = phys_addr & ~PAGE_MASK;
 159         phys_addr &= PAGE_MASK;
 160         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
 161
 162         prot = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY
 163                         | _PAGE_ACCESSED | _PAGE_TYPE_SMALL | flags);
 164
 165         /*
 166          * Ok, go for it..
 167          */
 168         area = get_vm_area(size, VM_IOREMAP);
 169         if (!area)
 170                 return NULL;
 171         area->phys_addr = phys_addr;
 172         addr = area->addr;
 173         if (remap_area_pages((unsigned long)addr, phys_addr, size, prot)) {
 174                 vunmap(addr);
 175                 return NULL;
 176         }
 177
 178         return (void __iomem *)(offset + (char *)addr);
 179 }
 180 EXPORT_SYMBOL(__ioremap);
 181
 182 void __iounmap(void __iomem *addr)
 183 {
 184         struct vm_struct *p;
 185
 186         if ((unsigned long)addr >= P4SEG)
 187                 return;
 188
 189         p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
 190         if (unlikely(!p)) {
 191                 printk (KERN_ERR "iounmap: bad address %p\n", addr);
 192                 return;
 193         }
 194
 195         kfree (p);
 196 }
 197 EXPORT_SYMBOL(__iounmap);