linux/arch/cris/mm/ioremap.c
<<
>>
Prefs
   1/*
   2 * arch/cris/mm/ioremap.c
   3 *
   4 * Re-map IO memory to kernel address space so that we can access it.
   5 * Needed for memory-mapped I/O devices mapped outside our normal DRAM
   6 * window (that is, all memory-mapped I/O devices).
   7 *
   8 * (C) Copyright 1995 1996 Linus Torvalds
   9 * CRIS-port by Axis Communications AB
  10 */
  11
  12#include <linux/vmalloc.h>
  13#include <linux/io.h>
  14#include <asm/pgalloc.h>
  15#include <arch/memmap.h>
  16
  17/*
  18 * Generic mapping function (not visible outside):
  19 */
  20
  21/*
  22 * Remap an arbitrary physical address space into the kernel virtual
  23 * address space. Needed when the kernel wants to access high addresses
  24 * directly.
  25 *
  26 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
  27 * have to convert them into an offset in a page-aligned mapping, but the
  28 * caller shouldn't need to know that small detail.
  29 */
  30void __iomem * __ioremap_prot(unsigned long phys_addr, unsigned long size, pgprot_t prot)
  31{
  32        void __iomem * addr;
  33        struct vm_struct * area;
  34        unsigned long offset, last_addr;
  35
  36        /* Don't allow wraparound or zero size */
  37        last_addr = phys_addr + size - 1;
  38        if (!size || last_addr < phys_addr)
  39                return NULL;
  40
  41        /*
  42         * Mappings have to be page-aligned
  43         */
  44        offset = phys_addr & ~PAGE_MASK;
  45        phys_addr &= PAGE_MASK;
  46        size = PAGE_ALIGN(last_addr+1) - phys_addr;
  47
  48        /*
  49         * Ok, go for it..
  50         */
  51        area = get_vm_area(size, VM_IOREMAP);
  52        if (!area)
  53                return NULL;
  54        addr = (void __iomem *)area->addr;
  55        if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
  56                               phys_addr, prot)) {
  57                vfree((void __force *)addr);
  58                return NULL;
  59        }
  60        return (void __iomem *) (offset + (char __iomem *)addr);
  61}
  62
  63void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
  64{
  65        return __ioremap_prot(phys_addr, size,
  66                              __pgprot(_PAGE_PRESENT | __READABLE |
  67                                       __WRITEABLE | _PAGE_GLOBAL |
  68                                       _PAGE_KERNEL | flags));
  69}
  70
  71/**
  72 * ioremap_nocache     -   map bus memory into CPU space
  73 * @offset:    bus address of the memory
  74 * @size:      size of the resource to map
  75 *
  76 * Must be freed with iounmap.
  77 */
  78
  79void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
  80{
  81        return __ioremap(phys_addr | MEM_NON_CACHEABLE, size, 0);
  82}
  83
  84void iounmap(volatile void __iomem *addr)
  85{
  86        if (addr > high_memory)
  87                return vfree((void *) (PAGE_MASK & (unsigned long) addr));
  88}
  89
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.