LXR linux/arch/sh/mm/ioremap.c

   1/*
   2 * arch/sh/mm/ioremap.c
   3 *
   4 * (C) Copyright 1995 1996 Linus Torvalds
   5 * (C) Copyright 2005 - 2010  Paul Mundt
   6 *
   7 * Re-map IO memory to kernel address space so that we can access it.
   8 * This is needed for high PCI addresses that aren't mapped in the
   9 * 640k-1MB IO memory area on PC's
  10 *
  11 * This file is subject to the terms and conditions of the GNU General
  12 * Public License. See the file "COPYING" in the main directory of this
  13 * archive for more details.
  14 */
  15#include <linux/vmalloc.h>
  16#include <linux/module.h>
  17#include <linux/slab.h>
  18#include <linux/mm.h>
  19#include <linux/pci.h>
  20#include <linux/io.h>
  21#include <asm/page.h>
  22#include <asm/pgalloc.h>
  23#include <asm/addrspace.h>
  24#include <asm/cacheflush.h>
  25#include <asm/tlbflush.h>
  26#include <asm/mmu.h>
  27
  28/*
  29 * Remap an arbitrary physical address space into the kernel virtual
  30 * address space. Needed when the kernel wants to access high addresses
  31 * directly.
  32 *
  33 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
  34 * have to convert them into an offset in a page-aligned mapping, but the
  35 * caller shouldn't need to know that small detail.
  36 */
  37void __iomem * __ref
  38__ioremap_caller(phys_addr_t phys_addr, unsigned long size,
  39                 pgprot_t pgprot, void *caller)
  40{
  41        struct vm_struct *area;
  42        unsigned long offset, last_addr, addr, orig_addr;
  43        void __iomem *mapped;
  44
  45        /* Don't allow wraparound or zero size */
  46        last_addr = phys_addr + size - 1;
  47        if (!size || last_addr < phys_addr)
  48                return NULL;
  49
  50        /*
  51         * If we can't yet use the regular approach, go the fixmap route.
  52         */
  53        if (!mem_init_done)
  54                return ioremap_fixed(phys_addr, size, pgprot);
  55
  56        /*
  57         * First try to remap through the PMB.
  58         * PMB entries are all pre-faulted.
  59         */
  60        mapped = pmb_remap_caller(phys_addr, size, pgprot, caller);
  61        if (mapped && !IS_ERR(mapped))
  62                return mapped;
  63
  64        /*
  65         * Mappings have to be page-aligned
  66         */
  67        offset = phys_addr & ~PAGE_MASK;
  68        phys_addr &= PAGE_MASK;
  69        size = PAGE_ALIGN(last_addr+1) - phys_addr;
  70
  71        /*
  72         * Ok, go for it..
  73         */
  74        area = get_vm_area_caller(size, VM_IOREMAP, caller);
  75        if (!area)
  76                return NULL;
  77        area->phys_addr = phys_addr;
  78        orig_addr = addr = (unsigned long)area->addr;
  79
  80        if (ioremap_page_range(addr, addr + size, phys_addr, pgprot)) {
  81                vunmap((void *)orig_addr);
  82                return NULL;
  83        }
  84
  85        return (void __iomem *)(offset + (char *)orig_addr);
  86}
  87EXPORT_SYMBOL(__ioremap_caller);
  88
  89/*
  90 * Simple checks for non-translatable mappings.
  91 */
  92static inline int iomapping_nontranslatable(unsigned long offset)
  93{
  94#ifdef CONFIG_29BIT
  95        /*
  96         * In 29-bit mode this includes the fixed P1/P2 areas, as well as
  97         * parts of P3.
  98         */
  99        if (PXSEG(offset) < P3SEG || offset >= P3_ADDR_MAX)
 100                return 1;
 101#endif
 102
 103        return 0;
 104}
 105
 106void __iounmap(void __iomem *addr)
 107{
 108        unsigned long vaddr = (unsigned long __force)addr;
 109        struct vm_struct *p;
 110
 111        /*
 112         * Nothing to do if there is no translatable mapping.
 113         */
 114        if (iomapping_nontranslatable(vaddr))
 115                return;
 116
 117        /*
 118         * There's no VMA if it's from an early fixed mapping.
 119         */
 120        if (iounmap_fixed(addr) == 0)
 121                return;
 122
 123        /*
 124         * If the PMB handled it, there's nothing else to do.
 125         */
 126        if (pmb_unmap(addr) == 0)
 127                return;
 128
 129        p = remove_vm_area((void *)(vaddr & PAGE_MASK));
 130        if (!p) {
 131                printk(KERN_ERR "%s: bad address %p\n", __func__, addr);
 132                return;
 133        }
 134
 135        kfree(p);
 136}
 137EXPORT_SYMBOL(__iounmap);
 138