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 (unsigned long phys_addr)
  20{
  21        return (void __iomem *) (__IA64_UNCACHED_OFFSET | phys_addr);
  22}
  23
  24void __iomem *
  25ioremap (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}
  92EXPORT_SYMBOL(ioremap);
  93
  94void __iomem *
  95ioremap_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}
 102EXPORT_SYMBOL(ioremap_nocache);
 103
 104void
 105iounmap (volatile void __iomem *addr)
 106{
 107        if (REGION_NUMBER(addr) == RGN_GATE)
 108                vunmap((void *) ((unsigned long) addr & PAGE_MASK));
 109}
 110EXPORT_SYMBOL(iounmap);
 111