arch/m32r/mm/ioremap.c

   1 /*
   2  *  linux/arch/m32r/mm/ioremap.c
   3  *
   4  *  Copyright (c) 2001, 2002  Hiroyuki Kondo
   5  *
   6  *  Taken from mips version.
   7  *    (C) Copyright 1995 1996 Linus Torvalds
   8  *    (C) Copyright 2001 Ralf Baechle
   9  */
  10
  11 /*
  12  * This file is subject to the terms and conditions of the GNU General Public
  13  * License.  See the file "COPYING" in the main directory of this archive
  14  * for more details.
  15  *
  16  */
  17
  18 #include <linux/module.h>
  19 #include <asm/addrspace.h>
  20 #include <asm/byteorder.h>
  21
  22 #include <linux/vmalloc.h>
  23 #include <linux/io.h>
  24 #include <asm/pgalloc.h>
  25
  26 /*
  27  * Generic mapping function (not visible outside):
  28  */
  29
  30 /*
  31  * Remap an arbitrary physical address space into the kernel virtual
  32  * address space. Needed when the kernel wants to access high addresses
  33  * directly.
  34  *
  35  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
  36  * have to convert them into an offset in a page-aligned mapping, but the
  37  * caller shouldn't need to know that small detail.
  38  */
  39
  40 #define IS_LOW512(addr) (!((unsigned long)(addr) & ~0x1fffffffUL))
  41
  42 void __iomem *
  43 __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
  44 {
  45         void __iomem * addr;
  46         struct vm_struct * area;
  47         unsigned long offset, last_addr;
  48         pgprot_t pgprot;
  49
  50         /* Don't allow wraparound or zero size */
  51         last_addr = phys_addr + size - 1;
  52         if (!size || last_addr < phys_addr)
  53                 return NULL;
  54
  55         /*
  56          * Map objects in the low 512mb of address space using KSEG1, otherwise
  57          * map using page tables.
  58          */
  59         if (IS_LOW512(phys_addr) && IS_LOW512(phys_addr + size - 1))
  60                 return (void *) KSEG1ADDR(phys_addr);
  61
  62         /*
  63          * Don't allow anybody to remap normal RAM that we're using..
  64          */
  65         if (phys_addr < virt_to_phys(high_memory)) {
  66                 char *t_addr, *t_end;
  67                 struct page *page;
  68
  69                 t_addr = __va(phys_addr);
  70                 t_end = t_addr + (size - 1);
  71
  72                 for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
  73                         if(!PageReserved(page))
  74                                 return NULL;
  75         }
  76
  77         pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | _PAGE_READ
  78                           | _PAGE_WRITE | flags);
  79
  80         /*
  81          * Mappings have to be page-aligned
  82          */
  83         offset = phys_addr & ~PAGE_MASK;
  84         phys_addr &= PAGE_MASK;
  85         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
  86
  87         /*
  88          * Ok, go for it..
  89          */
  90         area = get_vm_area(size, VM_IOREMAP);
  91         if (!area)
  92                 return NULL;
  93         area->phys_addr = phys_addr;
  94         addr = (void __iomem *) area->addr;
  95         if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
  96                                phys_addr, pgprot)) {
  97                 vunmap((void __force *) addr);
  98                 return NULL;
  99         }
 100
 101         return (void __iomem *) (offset + (char __iomem *)addr);
 102 }
 103
 104 #define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == KSEG1)
 105
 106 void iounmap(volatile void __iomem *addr)
 107 {
 108         if (!IS_KSEG1(addr))
 109                 vfree((void *) (PAGE_MASK & (unsigned long) addr));
 110 }
 111