LXR linux/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
  18static inline void __iomem *
  19__ioremap_uc(unsigned long phys_addr)
  20{
  21        return (void __iomem *) (__IA64_UNCACHED_OFFSET | phys_addr);
  22}
  23
  24void __iomem *
  25early_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
  34void __iomem *
  35ioremap (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}
 102EXPORT_SYMBOL(ioremap);
 103
 104void __iomem *
 105ioremap_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}
 112EXPORT_SYMBOL(ioremap_nocache);
 113
 114void
 115early_iounmap (volatile void __iomem *addr, unsigned long size)
 116{
 117}
 118
 119void
 120iounmap (volatile void __iomem *addr)
 121{
 122        if (REGION_NUMBER(addr) == RGN_GATE)
 123                vunmap((void *) ((unsigned long) addr & PAGE_MASK));
 124}
 125EXPORT_SYMBOL(iounmap);
 126