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
  17 void __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 }
  32 EXPORT_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  */
  41 void __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 }
  81 EXPORT_SYMBOL(ioremap_prot);
  82
  83
  84 void 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 }
  91 EXPORT_SYMBOL(iounmap);