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
  13 #include <asm/pgtable.h>
  14 #include <asm/addrspace.h>
  15
  16 /*
  17  * Re-map an arbitrary physical address space into the kernel virtual
  18  * address space. Needed when the kernel wants to access physical
  19  * memory directly.
  20  */
  21 void __iomem *__ioremap(unsigned long phys_addr, size_t size,
  22                         unsigned long flags)
  23 {
  24         unsigned long addr;
  25         struct vm_struct *area;
  26         unsigned long offset, last_addr;
  27         pgprot_t prot;
  28
  29         /*
  30          * Check if we can simply use the P4 segment. This area is
  31          * uncacheable, so if caching/buffering is requested, we can't
  32          * use it.
  33          */
  34         if ((phys_addr >= P4SEG) && (flags == 0))
  35                 return (void __iomem *)phys_addr;
  36
  37         /* Don't allow wraparound or zero size */
  38         last_addr = phys_addr + size - 1;
  39         if (!size || last_addr < phys_addr)
  40                 return NULL;
  41
  42         /*
  43          * XXX: When mapping regular RAM, we'd better make damn sure
  44          * it's never used for anything else.  But this is really the
  45          * caller's responsibility...
  46          */
  47         if (PHYSADDR(P2SEGADDR(phys_addr)) == phys_addr)
  48                 return (void __iomem *)P2SEGADDR(phys_addr);
  49
  50         /* Mappings have to be page-aligned */
  51         offset = phys_addr & ~PAGE_MASK;
  52         phys_addr &= PAGE_MASK;
  53         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
  54
  55         prot = __pgprot(_PAGE_PRESENT | _PAGE_GLOBAL | _PAGE_RW | _PAGE_DIRTY
  56                         | _PAGE_ACCESSED | _PAGE_TYPE_SMALL | flags);
  57
  58         /*
  59          * Ok, go for it..
  60          */
  61         area = get_vm_area(size, VM_IOREMAP);
  62         if (!area)
  63                 return NULL;
  64         area->phys_addr = phys_addr;
  65         addr = (unsigned long )area->addr;
  66         if (ioremap_page_range(addr, addr + size, phys_addr, prot)) {
  67                 vunmap((void *)addr);
  68                 return NULL;
  69         }
  70
  71         return (void __iomem *)(offset + (char *)addr);
  72 }
  73 EXPORT_SYMBOL(__ioremap);
  74
  75 void __iounmap(void __iomem *addr)
  76 {
  77         struct vm_struct *p;
  78
  79         if ((unsigned long)addr >= P4SEG)
  80                 return;
  81         if (PXSEG(addr) == P2SEG)
  82                 return;
  83
  84         p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
  85         if (unlikely(!p)) {
  86                 printk (KERN_ERR "iounmap: bad address %p\n", addr);
  87                 return;
  88         }
  89
  90         kfree (p);
  91 }
  92 EXPORT_SYMBOL(__iounmap);