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 #include <linux/io.h>
  11
  12 #include <asm/pgtable.h>
  13 #include <asm/addrspace.h>
  14
  15 /*
  16  * Re-map an arbitrary physical address space into the kernel virtual
  17  * address space. Needed when the kernel wants to access physical
  18  * memory directly.
  19  */
  20 void __iomem *__ioremap(unsigned long phys_addr, size_t size,
  21                         unsigned long flags)
  22 {
  23         unsigned long addr;
  24         struct vm_struct *area;
  25         unsigned long offset, last_addr;
  26         pgprot_t prot;
  27
  28         /*
  29          * Check if we can simply use the P4 segment. This area is
  30          * uncacheable, so if caching/buffering is requested, we can't
  31          * use it.
  32          */
  33         if ((phys_addr >= P4SEG) && (flags == 0))
  34                 return (void __iomem *)phys_addr;
  35
  36         /* Don't allow wraparound or zero size */
  37         last_addr = phys_addr + size - 1;
  38         if (!size || last_addr < phys_addr)
  39                 return NULL;
  40
  41         /*
  42          * XXX: When mapping regular RAM, we'd better make damn sure
  43          * it's never used for anything else.  But this is really the
  44          * caller's responsibility...
  45          */
  46         if (PHYSADDR(P2SEGADDR(phys_addr)) == phys_addr)
  47                 return (void __iomem *)P2SEGADDR(phys_addr);
  48
  49         /* Mappings have to be page-aligned */
  50         offset = phys_addr & ~PAGE_MASK;
  51         phys_addr &= PAGE_MASK;
  52         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
  53
  54         prot = __pgprot(_PAGE_PRESENT | _PAGE_GLOBAL | _PAGE_RW | _PAGE_DIRTY
  55                         | _PAGE_ACCESSED | _PAGE_TYPE_SMALL | flags);
  56
  57         /*
  58          * Ok, go for it..
  59          */
  60         area = get_vm_area(size, VM_IOREMAP);
  61         if (!area)
  62                 return NULL;
  63         area->phys_addr = phys_addr;
  64         addr = (unsigned long )area->addr;
  65         if (ioremap_page_range(addr, addr + size, phys_addr, prot)) {
  66                 vunmap((void *)addr);
  67                 return NULL;
  68         }
  69
  70         return (void __iomem *)(offset + (char *)addr);
  71 }
  72 EXPORT_SYMBOL(__ioremap);
  73
  74 void __iounmap(void __iomem *addr)
  75 {
  76         struct vm_struct *p;
  77
  78         if ((unsigned long)addr >= P4SEG)
  79                 return;
  80         if (PXSEG(addr) == P2SEG)
  81                 return;
  82
  83         p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
  84         if (unlikely(!p)) {
  85                 printk (KERN_ERR "iounmap: bad address %p\n", addr);
  86                 return;
  87         }
  88
  89         kfree (p);
  90 }
  91 EXPORT_SYMBOL(__iounmap);