release/src-rt-6.x.4708/linux/linux-2.6.36/arch/parisc/mm/ioremap.c

   1 /*
   2  * arch/parisc/mm/ioremap.c
   3  *
   4  * (C) Copyright 1995 1996 Linus Torvalds
   5  * (C) Copyright 2001-2006 Helge Deller <deller@gmx.de>
   6  * (C) Copyright 2005 Kyle McMartin <kyle@parisc-linux.org>
   7  */
   8
   9 #include <linux/vmalloc.h>
  10 #include <linux/errno.h>
  11 #include <linux/module.h>
  12 #include <linux/io.h>
  13 #include <asm/pgalloc.h>
  14
  15 /*
  16  * Generic mapping function (not visible outside):
  17  */
  18
  19 /*
  20  * Remap an arbitrary physical address space into the kernel virtual
  21  * address space.
  22  *
  23  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
  24  * have to convert them into an offset in a page-aligned mapping, but the
  25  * caller shouldn't need to know that small detail.
  26  */
  27 void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
  28 {
  29         void __iomem *addr;
  30         struct vm_struct *area;
  31         unsigned long offset, last_addr;
  32         pgprot_t pgprot;
  33
  34 #ifdef CONFIG_EISA
  35         unsigned long end = phys_addr + size - 1;
  36         /* Support EISA addresses */
  37         if ((phys_addr >= 0x00080000 && end < 0x000fffff) ||
  38             (phys_addr >= 0x00500000 && end < 0x03bfffff)) {
  39                 phys_addr |= F_EXTEND(0xfc000000);
  40                 flags |= _PAGE_NO_CACHE;
  41         }
  42 #endif
  43
  44         /* Don't allow wraparound or zero size */
  45         last_addr = phys_addr + size - 1;
  46         if (!size || last_addr < phys_addr)
  47                 return NULL;
  48
  49         /*
  50          * Don't allow anybody to remap normal RAM that we're using..
  51          */
  52         if (phys_addr < virt_to_phys(high_memory)) {
  53                 char *t_addr, *t_end;
  54                 struct page *page;
  55
  56                 t_addr = __va(phys_addr);
  57                 t_end = t_addr + (size - 1);
  58
  59                 for (page = virt_to_page(t_addr);
  60                      page <= virt_to_page(t_end); page++) {
  61                         if(!PageReserved(page))
  62                                 return NULL;
  63                 }
  64         }
  65
  66         pgprot = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY |
  67                           _PAGE_ACCESSED | flags);
  68
  69         /*
  70          * Mappings have to be page-aligned
  71          */
  72         offset = phys_addr & ~PAGE_MASK;
  73         phys_addr &= PAGE_MASK;
  74         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
  75
  76         /*
  77          * Ok, go for it..
  78          */
  79         area = get_vm_area(size, VM_IOREMAP);
  80         if (!area)
  81                 return NULL;
  82
  83         addr = (void __iomem *) area->addr;
  84         if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
  85                                phys_addr, pgprot)) {
  86                 vfree(addr);
  87                 return NULL;
  88         }
  89
  90         return (void __iomem *) (offset + (char __iomem *)addr);
  91 }
  92 EXPORT_SYMBOL(__ioremap);
  93
  94 void iounmap(const volatile void __iomem *addr)
  95 {
  96         if (addr > high_memory)
  97                 return vfree((void *) (PAGE_MASK & (unsigned long __force) addr));
  98 }
  99 EXPORT_SYMBOL(iounmap);