arch/ia64/mm/ioremap.c

   1 /*
   2  * (c) Copyright 2006 Hewlett-Packard Development Company, L.P.
   3  *      Bjorn Helgaas <bjorn.helgaas@hp.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/compiler.h>
  11 #include <linux/module.h>
  12 #include <linux/efi.h>
  13 #include <asm/io.h>
  14 #include <asm/meminit.h>
  15
  16 static inline void __iomem *
  17 __ioremap (unsigned long offset, unsigned long size)
  18 {
  19         return (void __iomem *) (__IA64_UNCACHED_OFFSET | offset);
  20 }
  21
  22 void __iomem *
  23 ioremap (unsigned long offset, unsigned long size)
  24 {
  25         u64 attr;
  26         unsigned long gran_base, gran_size;
  27
  28         /*
  29          * For things in kern_memmap, we must use the same attribute
  30          * as the rest of the kernel.  For more details, see
  31          * Documentation/ia64/aliasing.txt.
  32          */
  33         attr = kern_mem_attribute(offset, size);
  34         if (attr & EFI_MEMORY_WB)
  35                 return phys_to_virt(offset);
  36         else if (attr & EFI_MEMORY_UC)
  37                 return __ioremap(offset, size);
  38
  39         /*
  40          * Some chipsets don't support UC access to memory.  If
  41          * WB is supported for the whole granule, we prefer that.
  42          */
  43         gran_base = GRANULEROUNDDOWN(offset);
  44         gran_size = GRANULEROUNDUP(offset + size) - gran_base;
  45         if (efi_mem_attribute(gran_base, gran_size) & EFI_MEMORY_WB)
  46                 return phys_to_virt(offset);
  47
  48         return __ioremap(offset, size);
  49 }
  50 EXPORT_SYMBOL(ioremap);
  51
  52 void __iomem *
  53 ioremap_nocache (unsigned long offset, unsigned long size)
  54 {
  55         if (kern_mem_attribute(offset, size) & EFI_MEMORY_WB)
  56                 return 0;
  57
  58         return __ioremap(offset, size);
  59 }
  60 EXPORT_SYMBOL(ioremap_nocache);