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         /*
  44          * XXX: When mapping regular RAM, we'd better make damn sure
  45          * it's never used for anything else.  But this is really the
  46          * caller's responsibility...
  47          */
  48         if (PHYSADDR(P2SEGADDR(phys_addr)) == phys_addr)
  49                 return (void __iomem *)P2SEGADDR(phys_addr);
  50
  51         /* Mappings have to be page-aligned */
  52         offset = phys_addr & ~PAGE_MASK;
  53         phys_addr &= PAGE_MASK;
  54         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
  55
  56         prot = __pgprot(_PAGE_PRESENT | _PAGE_GLOBAL | _PAGE_RW | _PAGE_DIRTY
  57                         | _PAGE_ACCESSED | _PAGE_TYPE_SMALL | flags);
  58
  59         /*
  60          * Ok, go for it..
  61          */
  62         area = get_vm_area(size, VM_IOREMAP);
  63         if (!area)
  64                 return NULL;
  65         area->phys_addr = phys_addr;
  66         addr = (unsigned long )area->addr;
  67         if (ioremap_page_range(addr, addr + size, phys_addr, prot)) {
  68                 vunmap((void *)addr);
  69                 return NULL;
  70         }
  71
  72         return (void __iomem *)(offset + (char *)addr);
  73 }
  74 EXPORT_SYMBOL(__ioremap);
  75
  76 void __iounmap(void __iomem *addr)
  77 {
  78         struct vm_struct *p;
  79
  80         if ((unsigned long)addr >= P4SEG)
  81                 return;
  82         if (PXSEG(addr) == P2SEG)
  83                 return;
  84
  85         p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
  86         if (unlikely(!p)) {
  87                 printk (KERN_ERR "iounmap: bad address %p\n", addr);
  88                 return;
  89         }
  90
  91         kfree (p);
  92 }
  93 EXPORT_SYMBOL(__iounmap);