linux/arch/avr32/mm/ioremap.c
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   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 */
  21void __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}
  73EXPORT_SYMBOL(__ioremap);
  74
  75void __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}
  92EXPORT_SYMBOL(__iounmap);
  93