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_uc(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         u64 attr;
  28         attr = kern_mem_attribute(phys_addr, size);
  29         if (attr & EFI_MEMORY_WB)
  30                 return (void __iomem *) phys_to_virt(phys_addr);
  31         return __ioremap_uc(phys_addr);
  32 }
  33
  34 void __iomem *
  35 ioremap (unsigned long phys_addr, unsigned long size)
  36 {
  37         void __iomem *addr;
  38         struct vm_struct *area;
  39         unsigned long offset;
  40         pgprot_t prot;
  41         u64 attr;
  42         unsigned long gran_base, gran_size;
  43         unsigned long page_base;
  44
  45         /*
  46          * For things in kern_memmap, we must use the same attribute
  47          * as the rest of the kernel.  For more details, see
  48          * Documentation/ia64/aliasing.txt.
  49          */
  50         attr = kern_mem_attribute(phys_addr, size);
  51         if (attr & EFI_MEMORY_WB)
  52                 return (void __iomem *) phys_to_virt(phys_addr);
  53         else if (attr & EFI_MEMORY_UC)
  54                 return __ioremap_uc(phys_addr);
  55
  56         /*
  57          * Some chipsets don't support UC access to memory.  If
  58          * WB is supported for the whole granule, we prefer that.
  59          */
  60         gran_base = GRANULEROUNDDOWN(phys_addr);
  61         gran_size = GRANULEROUNDUP(phys_addr + size) - gran_base;
  62         if (efi_mem_attribute(gran_base, gran_size) & EFI_MEMORY_WB)
  63                 return (void __iomem *) phys_to_virt(phys_addr);
  64
  65         /*
  66          * WB is not supported for the whole granule, so we can't use
  67          * the region 7 identity mapping.  If we can safely cover the
  68          * area with kernel page table mappings, we can use those
  69          * instead.
  70          */
  71         page_base = phys_addr & PAGE_MASK;
  72         size = PAGE_ALIGN(phys_addr + size) - page_base;
  73         if (efi_mem_attribute(page_base, size) & EFI_MEMORY_WB) {
  74                 prot = PAGE_KERNEL;
  75
  76                 /*
  77                  * Mappings have to be page-aligned
  78                  */
  79                 offset = phys_addr & ~PAGE_MASK;
  80                 phys_addr &= PAGE_MASK;
  81
  82                 /*
  83                  * Ok, go for it..
  84                  */
  85                 area = get_vm_area(size, VM_IOREMAP);
  86                 if (!area)
  87                         return NULL;
  88
  89                 area->phys_addr = phys_addr;
  90                 addr = (void __iomem *) area->addr;
  91                 if (ioremap_page_range((unsigned long) addr,
  92                                 (unsigned long) addr + size, phys_addr, prot)) {
  93                         vunmap((void __force *) addr);
  94                         return NULL;
  95                 }
  96
  97                 return (void __iomem *) (offset + (char __iomem *)addr);
  98         }
  99
 100         return __ioremap_uc(phys_addr);
 101 }
 102 EXPORT_SYMBOL(ioremap);
 103
 104 void __iomem *
 105 ioremap_nocache (unsigned long phys_addr, unsigned long size)
 106 {
 107         if (kern_mem_attribute(phys_addr, size) & EFI_MEMORY_WB)
 108                 return NULL;
 109
 110         return __ioremap_uc(phys_addr);
 111 }
 112 EXPORT_SYMBOL(ioremap_nocache);
 113
 114 void
 115 early_iounmap (volatile void __iomem *addr, unsigned long size)
 116 {
 117 }
 118
 119 void
 120 iounmap (volatile void __iomem *addr)
 121 {
 122         if (REGION_NUMBER(addr) == RGN_GATE)
 123                 vunmap((void *) ((unsigned long) addr & PAGE_MASK));
 124 }
 125 EXPORT_SYMBOL(iounmap);