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

   1/*
   2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 */
   8
   9#include <linux/vmalloc.h>
  10#include <linux/init.h>
  11#include <linux/module.h>
  12#include <linux/io.h>
  13#include <linux/mm.h>
  14#include <linux/slab.h>
  15#include <linux/cache.h>
  16
  17void __iomem *ioremap(unsigned long paddr, unsigned long size)
  18{
  19        unsigned long end;
  20
  21        /* Don't allow wraparound or zero size */
  22        end = paddr + size - 1;
  23        if (!size || (end < paddr))
  24                return NULL;
  25
  26        /* If the region is h/w uncached, avoid MMU mappings */
  27        if (paddr >= ARC_UNCACHED_ADDR_SPACE)
  28                return (void __iomem *)paddr;
  29
  30        return ioremap_prot(paddr, size, PAGE_KERNEL_NO_CACHE);
  31}
  32EXPORT_SYMBOL(ioremap);
  33
  34/*
  35 * ioremap with access flags
  36 * Cache semantics wise it is same as ioremap - "forced" uncached.
  37 * However unline vanilla ioremap which bypasses ARC MMU for addresses in
  38 * ARC hardware uncached region, this one still goes thru the MMU as caller
  39 * might need finer access control (R/W/X)
  40 */
  41void __iomem *ioremap_prot(phys_addr_t paddr, unsigned long size,
  42                           unsigned long flags)
  43{
  44        void __iomem *vaddr;
  45        struct vm_struct *area;
  46        unsigned long off, end;
  47        pgprot_t prot = __pgprot(flags);
  48
  49        /* Don't allow wraparound, zero size */
  50        end = paddr + size - 1;
  51        if ((!size) || (end < paddr))
  52                return NULL;
  53
  54        /* An early platform driver might end up here */
  55        if (!slab_is_available())
  56                return NULL;
  57
  58        /* force uncached */
  59        prot = pgprot_noncached(prot);
  60
  61        /* Mappings have to be page-aligned */
  62        off = paddr & ~PAGE_MASK;
  63        paddr &= PAGE_MASK;
  64        size = PAGE_ALIGN(end + 1) - paddr;
  65
  66        /*
  67         * Ok, go for it..
  68         */
  69        area = get_vm_area(size, VM_IOREMAP);
  70        if (!area)
  71                return NULL;
  72        area->phys_addr = paddr;
  73        vaddr = (void __iomem *)area->addr;
  74        if (ioremap_page_range((unsigned long)vaddr,
  75                               (unsigned long)vaddr + size, paddr, prot)) {
  76                vunmap((void __force *)vaddr);
  77                return NULL;
  78        }
  79        return (void __iomem *)(off + (char __iomem *)vaddr);
  80}
  81EXPORT_SYMBOL(ioremap_prot);
  82
  83
  84void iounmap(const void __iomem *addr)
  85{
  86        if (addr >= (void __force __iomem *)ARC_UNCACHED_ADDR_SPACE)
  87                return;
  88
  89        vfree((void *)(PAGE_MASK & (unsigned long __force)addr));
  90}
  91EXPORT_SYMBOL(iounmap);
  92