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 early_ioremap (unsigned long phys_addr, unsigned long size)
  26 {
  27         return __ioremap(phys_addr);
  28 }
  29
  30 void __iomem *
  31 ioremap (unsigned long phys_addr, unsigned long size)
  32 {
  33         void __iomem *addr;
  34         struct vm_struct *area;
  35         unsigned long offset;
  36         pgprot_t prot;
  37         u64 attr;
  38         unsigned long gran_base, gran_size;
  39         unsigned long page_base;
  40
  41         /*
  42          * For things in kern_memmap, we must use the same attribute
  43          * as the rest of the kernel.  For more details, see
  44          * Documentation/ia64/aliasing.txt.
  45          */
  46         attr = kern_mem_attribute(phys_addr, size);
  47         if (attr & EFI_MEMORY_WB)
  48                 return (void __iomem *) phys_to_virt(phys_addr);
  49         else if (attr & EFI_MEMORY_UC)
  50                 return __ioremap(phys_addr);
  51
  52         /*
  53          * Some chipsets don't support UC access to memory.  If
  54          * WB is supported for the whole granule, we prefer that.
  55          */
  56         gran_base = GRANULEROUNDDOWN(phys_addr);
  57         gran_size = GRANULEROUNDUP(phys_addr + size) - gran_base;
  58         if (efi_mem_attribute(gran_base, gran_size) & EFI_MEMORY_WB)
  59                 return (void __iomem *) phys_to_virt(phys_addr);
  60
  61         /*
  62          * WB is not supported for the whole granule, so we can't use
  63          * the region 7 identity mapping.  If we can safely cover the
  64          * area with kernel page table mappings, we can use those
  65          * instead.
  66          */
  67         page_base = phys_addr & PAGE_MASK;
  68         size = PAGE_ALIGN(phys_addr + size) - page_base;
  69         if (efi_mem_attribute(page_base, size) & EFI_MEMORY_WB) {
  70                 prot = PAGE_KERNEL;
  71
  72                 /*
  73                  * Mappings have to be page-aligned
  74                  */
  75                 offset = phys_addr & ~PAGE_MASK;
  76                 phys_addr &= PAGE_MASK;
  77
  78                 /*
  79                  * Ok, go for it..
  80                  */
  81                 area = get_vm_area(size, VM_IOREMAP);
  82                 if (!area)
  83                         return NULL;
  84
  85                 area->phys_addr = phys_addr;
  86                 addr = (void __iomem *) area->addr;
  87                 if (ioremap_page_range((unsigned long) addr,
  88                                 (unsigned long) addr + size, phys_addr, prot)) {
  89                         vunmap((void __force *) addr);
  90                         return NULL;
  91                 }
  92
  93                 return (void __iomem *) (offset + (char __iomem *)addr);
  94         }
  95
  96         return __ioremap(phys_addr);
  97 }
  98 EXPORT_SYMBOL(ioremap);
  99
 100 void __iomem *
 101 ioremap_nocache (unsigned long phys_addr, unsigned long size)
 102 {
 103         if (kern_mem_attribute(phys_addr, size) & EFI_MEMORY_WB)
 104                 return NULL;
 105
 106         return __ioremap(phys_addr);
 107 }
 108 EXPORT_SYMBOL(ioremap_nocache);
 109
 110 void
 111 early_iounmap (volatile void __iomem *addr, unsigned long size)
 112 {
 113 }
 114
 115 void
 116 iounmap (volatile void __iomem *addr)
 117 {
 118         if (REGION_NUMBER(addr) == RGN_GATE)
 119                 vunmap((void *) ((unsigned long) addr & PAGE_MASK));
 120 }
 121 EXPORT_SYMBOL(iounmap);