SAFE public projects git trees. - safe/jmp/linux-2.6/blob - arch/mips/mm/ioremap.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * (C) Copyright 1995 1996 Linus Torvalds
   7  * (C) Copyright 2001, 2002 Ralf Baechle
   8  */
   9 #include <linux/module.h>
  10 #include <asm/addrspace.h>
  11 #include <asm/byteorder.h>
  12
  13 #include <linux/vmalloc.h>
  14 #include <asm/cacheflush.h>
  15 #include <asm/io.h>
  16 #include <asm/tlbflush.h>
  17
  18 static inline void remap_area_pte(pte_t * pte, unsigned long address,
  19         phys_t size, phys_t phys_addr, unsigned long flags)
  20 {
  21         phys_t end;
  22         unsigned long pfn;
  23         pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | __READABLE
  24                                    | __WRITEABLE | flags);
  25
  26         address &= ~PMD_MASK;
  27         end = address + size;
  28         if (end > PMD_SIZE)
  29                 end = PMD_SIZE;
  30         if (address >= end)
  31                 BUG();
  32         pfn = phys_addr >> PAGE_SHIFT;
  33         do {
  34                 if (!pte_none(*pte)) {
  35                         printk("remap_area_pte: page already exists\n");
  36                         BUG();
  37                 }
  38                 set_pte(pte, pfn_pte(pfn, pgprot));
  39                 address += PAGE_SIZE;
  40                 pfn++;
  41                 pte++;
  42         } while (address && (address < end));
  43 }
  44
  45 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address,
  46         phys_t size, phys_t phys_addr, unsigned long flags)
  47 {
  48         phys_t end;
  49
  50         address &= ~PGDIR_MASK;
  51         end = address + size;
  52         if (end > PGDIR_SIZE)
  53                 end = PGDIR_SIZE;
  54         phys_addr -= address;
  55         if (address >= end)
  56                 BUG();
  57         do {
  58                 pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
  59                 if (!pte)
  60                         return -ENOMEM;
  61                 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
  62                 address = (address + PMD_SIZE) & PMD_MASK;
  63                 pmd++;
  64         } while (address && (address < end));
  65         return 0;
  66 }
  67
  68 static int remap_area_pages(unsigned long address, phys_t phys_addr,
  69         phys_t size, unsigned long flags)
  70 {
  71         int error;
  72         pgd_t * dir;
  73         unsigned long end = address + size;
  74
  75         phys_addr -= address;
  76         dir = pgd_offset(&init_mm, address);
  77         flush_cache_all();
  78         if (address >= end)
  79                 BUG();
  80         spin_lock(&init_mm.page_table_lock);
  81         do {
  82                 pud_t *pud;
  83                 pmd_t *pmd;
  84
  85                 error = -ENOMEM;
  86                 pud = pud_alloc(&init_mm, dir, address);
  87                 if (!pud)
  88                         break;
  89                 pmd = pmd_alloc(&init_mm, pud, address);
  90                 if (!pmd)
  91                         break;
  92                 if (remap_area_pmd(pmd, address, end - address,
  93                                          phys_addr + address, flags))
  94                         break;
  95                 error = 0;
  96                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
  97                 dir++;
  98         } while (address && (address < end));
  99         spin_unlock(&init_mm.page_table_lock);
 100         flush_tlb_all();
 101         return error;
 102 }
 103
 104 /*
 105  * Generic mapping function (not visible outside):
 106  */
 107
 108 /*
 109  * Remap an arbitrary physical address space into the kernel virtual
 110  * address space. Needed when the kernel wants to access high addresses
 111  * directly.
 112  *
 113  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 114  * have to convert them into an offset in a page-aligned mapping, but the
 115  * caller shouldn't need to know that small detail.
 116  */
 117
 118 #define IS_LOW512(addr) (!((phys_t)(addr) & (phys_t) ~0x1fffffffULL))
 119
 120 void __iomem * __ioremap(phys_t phys_addr, phys_t size, unsigned long flags)
 121 {
 122         struct vm_struct * area;
 123         unsigned long offset;
 124         phys_t last_addr;
 125         void * addr;
 126
 127         phys_addr = fixup_bigphys_addr(phys_addr, size);
 128
 129         /* Don't allow wraparound or zero size */
 130         last_addr = phys_addr + size - 1;
 131         if (!size || last_addr < phys_addr)
 132                 return NULL;
 133
 134         /*
 135          * Map uncached objects in the low 512mb of address space using KSEG1,
 136          * otherwise map using page tables.
 137          */
 138         if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) &&
 139             flags == _CACHE_UNCACHED)
 140                 return (void __iomem *) CKSEG1ADDR(phys_addr);
 141
 142         /*
 143          * Don't allow anybody to remap normal RAM that we're using..
 144          */
 145         if (phys_addr < virt_to_phys(high_memory)) {
 146                 char *t_addr, *t_end;
 147                 struct page *page;
 148
 149                 t_addr = __va(phys_addr);
 150                 t_end = t_addr + (size - 1);
 151
 152                 for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
 153                         if(!PageReserved(page))
 154                                 return NULL;
 155         }
 156
 157         /*
 158          * Mappings have to be page-aligned
 159          */
 160         offset = phys_addr & ~PAGE_MASK;
 161         phys_addr &= PAGE_MASK;
 162         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
 163
 164         /*
 165          * Ok, go for it..
 166          */
 167         area = get_vm_area(size, VM_IOREMAP);
 168         if (!area)
 169                 return NULL;
 170         addr = area->addr;
 171         if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
 172                 vunmap(addr);
 173                 return NULL;
 174         }
 175
 176         return (void __iomem *) (offset + (char *)addr);
 177 }
 178
 179 #define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
 180
 181 void __iounmap(volatile void __iomem *addr)
 182 {
 183         struct vm_struct *p;
 184
 185         if (IS_KSEG1(addr))
 186                 return;
 187
 188         p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));
 189         if (!p)
 190                 printk(KERN_ERR "iounmap: bad address %p\n", addr);
 191
 192         kfree(p);
 193 }
 194
 195 EXPORT_SYMBOL(__ioremap);
 196 EXPORT_SYMBOL(__iounmap);