arch/cris/mm/ioremap.c

   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  */
  30 void __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
  63 void __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
  79 void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
  80 {
  81         return __ioremap(phys_addr | MEM_NON_CACHEABLE, size, 0);
  82 }
  83
  84 void iounmap(volatile void __iomem *addr)
  85 {
  86         if (addr > high_memory)
  87                 return vfree((void *) (PAGE_MASK & (unsigned long) addr));
  88 }