arch/metag/mm/ioremap.c

   1 /*
   2  * Re-map IO memory to kernel address space so that we can access it.
   3  * Needed for memory-mapped I/O devices mapped outside our normal DRAM
   4  * window (that is, all memory-mapped I/O devices).
   5  *
   6  * Copyright (C) 1995,1996 Linus Torvalds
   7  *
   8  * Meta port based on CRIS-port by Axis Communications AB
   9  */
  10
  11 #include <linux/vmalloc.h>
  12 #include <linux/io.h>
  13 #include <linux/export.h>
  14 #include <linux/slab.h>
  15 #include <linux/mm.h>
  16
  17 #include <asm/pgtable.h>
  18
  19 /*
  20  * Remap an arbitrary physical address space into the kernel virtual
  21  * address space. Needed when the kernel wants to access high addresses
  22  * directly.
  23  *
  24  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
  25  * have to convert them into an offset in a page-aligned mapping, but the
  26  * caller shouldn't need to know that small detail.
  27  */
  28 void __iomem *__ioremap(unsigned long phys_addr, size_t size,
  29                         unsigned long flags)
  30 {
  31         unsigned long addr;
  32         struct vm_struct *area;
  33         unsigned long offset, last_addr;
  34         pgprot_t prot;
  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         /* Custom region addresses are accessible and uncached by default. */
  42         if (phys_addr >= LINSYSCUSTOM_BASE &&
  43             phys_addr < (LINSYSCUSTOM_BASE + LINSYSCUSTOM_LIMIT))
  44                 return (__force void __iomem *) phys_addr;
  45
  46         /*
  47          * Mappings have to be page-aligned
  48          */
  49         offset = phys_addr & ~PAGE_MASK;
  50         phys_addr &= PAGE_MASK;
  51         size = PAGE_ALIGN(last_addr+1) - phys_addr;
  52         prot = __pgprot(_PAGE_PRESENT | _PAGE_WRITE | _PAGE_DIRTY |
  53                         _PAGE_ACCESSED | _PAGE_KERNEL | _PAGE_CACHE_WIN0 |
  54                         flags);
  55
  56         /*
  57          * Ok, go for it..
  58          */
  59         area = get_vm_area(size, VM_IOREMAP);
  60         if (!area)
  61                 return NULL;
  62         area->phys_addr = phys_addr;
  63         addr = (unsigned long) area->addr;
  64         if (ioremap_page_range(addr, addr + size, phys_addr, prot)) {
  65                 vunmap((void *) addr);
  66                 return NULL;
  67         }
  68         return (__force void __iomem *) (offset + (char *)addr);
  69 }
  70 EXPORT_SYMBOL(__ioremap);
  71
  72 void __iounmap(void __iomem *addr)
  73 {
  74         struct vm_struct *p;
  75
  76         if ((__force unsigned long)addr >= LINSYSCUSTOM_BASE &&
  77             (__force unsigned long)addr < (LINSYSCUSTOM_BASE +
  78                                            LINSYSCUSTOM_LIMIT))
  79                 return;
  80
  81         p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
  82         if (unlikely(!p)) {
  83                 pr_err("iounmap: bad address %p\n", addr);
  84                 return;
  85         }
  86
  87         kfree(p);
  88 }
  89 EXPORT_SYMBOL(__iounmap);