arch/ia64/mm/ioremap.c

   1 /*
   2  * (c) Copyright 2006, 2007 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 <linux/io.h>
  14 #include <linux/vmalloc.h>
  15 #include <asm/io.h>
  16 #include <asm/meminit.h>
  17
  18 static inline void __iomem *
  19 __ioremap (unsigned long phys_addr)
  20 {
  21         return (void __iomem *) (__IA64_UNCACHED_OFFSET | phys_addr);
  22 }
  23
  24 void __iomem *
  25 ioremap (unsigned long phys_addr, unsigned long size)
  26 {
  27         void __iomem *addr;
  28         struct vm_struct *area;
  29         unsigned long offset;
  30         pgprot_t prot;
  31         u64 attr;
  32         unsigned long gran_base, gran_size;
  33         unsigned long page_base;
  34
  35         /*
  36          * For things in kern_memmap, we must use the same attribute
  37          * as the rest of the kernel.  For more details, see
  38          * Documentation/ia64/aliasing.txt.
  39          */
  40         attr = kern_mem_attribute(phys_addr, size);
  41         if (attr & EFI_MEMORY_WB)
  42                 return (void __iomem *) phys_to_virt(phys_addr);
  43         else if (attr & EFI_MEMORY_UC)
  44                 return __ioremap(phys_addr);
  45
  46         /*
  47          * Some chipsets don't support UC access to memory.  If
  48          * WB is supported for the whole granule, we prefer that.
  49          */
  50         gran_base = GRANULEROUNDDOWN(phys_addr);
  51         gran_size = GRANULEROUNDUP(phys_addr + size) - gran_base;
  52         if (efi_mem_attribute(gran_base, gran_size) & EFI_MEMORY_WB)
  53                 return (void __iomem *) phys_to_virt(phys_addr);
  54
  55         /*
  56          * WB is not supported for the whole granule, so we can't use
  57          * the region 7 identity mapping.  If we can safely cover the
  58          * area with kernel page table mappings, we can use those
  59          * instead.
  60          */
  61         page_base = phys_addr & PAGE_MASK;
  62         size = PAGE_ALIGN(phys_addr + size) - page_base;
  63         if (efi_mem_attribute(page_base, size) & EFI_MEMORY_WB) {
  64                 prot = PAGE_KERNEL;
  65
  66                 /*
  67                  * Mappings have to be page-aligned
  68                  */
  69                 offset = phys_addr & ~PAGE_MASK;
  70                 phys_addr &= PAGE_MASK;
  71
  72                 /*
  73                  * Ok, go for it..
  74                  */
  75                 area = get_vm_area(size, VM_IOREMAP);
  76                 if (!area)
  77                         return NULL;
  78
  79                 area->phys_addr = phys_addr;
  80                 addr = (void __iomem *) area->addr;
  81                 if (ioremap_page_range((unsigned long) addr,
  82                                 (unsigned long) addr + size, phys_addr, prot)) {
  83                         vunmap((void __force *) addr);
  84                         return NULL;
  85                 }
  86
  87                 return (void __iomem *) (offset + (char __iomem *)addr);
  88         }
  89
  90         return __ioremap(phys_addr);
  91 }
  92 EXPORT_SYMBOL(ioremap);
  93
  94 void __iomem *
  95 ioremap_nocache (unsigned long phys_addr, unsigned long size)
  96 {
  97         if (kern_mem_attribute(phys_addr, size) & EFI_MEMORY_WB)
  98                 return NULL;
  99
 100         return __ioremap(phys_addr);
 101 }
 102 EXPORT_SYMBOL(ioremap_nocache);
 103
 104 void
 105 iounmap (volatile void __iomem *addr)
 106 {
 107         if (REGION_NUMBER(addr) == RGN_GATE)
 108                 vunmap((void *) ((unsigned long) addr & PAGE_MASK));
 109 }
 110 EXPORT_SYMBOL(iounmap);