release/src-rt-6.x.4708/linux/linux-2.6.36/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/mm.h>
  10 #include <linux/module.h>
  11 #include <linux/io.h>
  12 #include <linux/slab.h>
  13
  14 #include <asm/pgtable.h>
  15 #include <asm/addrspace.h>
  16
  17 /*
  18  * Re-map an arbitrary physical address space into the kernel virtual
  19  * address space. Needed when the kernel wants to access physical
  20  * memory directly.
  21  */
  22 void __iomem *__ioremap(unsigned long phys_addr, size_t size,
  23                         unsigned long flags)
  24 {
  25         unsigned long addr;
  26         struct vm_struct *area;
  27         unsigned long offset, last_addr;
  28         pgprot_t prot;
  29
  30         /*
  31          * Check if we can simply use the P4 segment. This area is
  32          * uncacheable, so if caching/buffering is requested, we can't
  33          * use it.
  34          */
  35         if ((phys_addr >= P4SEG) && (flags == 0))
  36                 return (void __iomem *)phys_addr;
  37
  38         /* Don't allow wraparound or zero size */
  39         last_addr = phys_addr + size - 1;
  40         if (!size || last_addr < phys_addr)
  41                 return NULL;
  42
  43         if (PHYSADDR(P2SEGADDR(phys_addr)) == phys_addr)
  44                 return (void __iomem *)P2SEGADDR(phys_addr);
  45
  46         /* Mappings have to be page-aligned */
  47         offset = phys_addr & ~PAGE_MASK;
  48         phys_addr &= PAGE_MASK;
  49         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
  50
  51         prot = __pgprot(_PAGE_PRESENT | _PAGE_GLOBAL | _PAGE_RW | _PAGE_DIRTY
  52                         | _PAGE_ACCESSED | _PAGE_TYPE_SMALL | flags);
  53
  54         /*
  55          * Ok, go for it..
  56          */
  57         area = get_vm_area(size, VM_IOREMAP);
  58         if (!area)
  59                 return NULL;
  60         area->phys_addr = phys_addr;
  61         addr = (unsigned long )area->addr;
  62         if (ioremap_page_range(addr, addr + size, phys_addr, prot)) {
  63                 vunmap((void *)addr);
  64                 return NULL;
  65         }
  66
  67         return (void __iomem *)(offset + (char *)addr);
  68 }
  69 EXPORT_SYMBOL(__ioremap);
  70
  71 void __iounmap(void __iomem *addr)
  72 {
  73         struct vm_struct *p;
  74
  75         if ((unsigned long)addr >= P4SEG)
  76                 return;
  77         if (PXSEG(addr) == P2SEG)
  78                 return;
  79
  80         p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
  81         if (unlikely(!p)) {
  82                 printk (KERN_ERR "iounmap: bad address %p\n", addr);
  83                 return;
  84         }
  85
  86         kfree (p);
  87 }
  88 EXPORT_SYMBOL(__iounmap);