arch/s390/mm/ioremap.c

   1 /*
   2  *  arch/s390/mm/ioremap.c
   3  *
   4  *  S390 version
   5  *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
   6  *    Author(s): Hartmut Penner (hp@de.ibm.com)
   7  *
   8  *  Derived from "arch/i386/mm/extable.c"
   9  *    (C) Copyright 1995 1996 Linus Torvalds
  10  *
  11  * Re-map IO memory to kernel address space so that we can access it.
  12  * This is needed for high PCI addresses that aren't mapped in the
  13  * 640k-1MB IO memory area on PC's
  14  */
  15
  16 #include <linux/vmalloc.h>
  17 #include <linux/mm.h>
  18 #include <linux/io.h>
  19 #include <asm/pgalloc.h>
  20
  21 /*
  22  * Generic mapping function (not visible outside):
  23  */
  24
  25 /*
  26  * Remap an arbitrary physical address space into the kernel virtual
  27  * address space. Needed when the kernel wants to access high addresses
  28  * directly.
  29  */
  30 void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
  31 {
  32         void * addr;
  33         struct vm_struct * area;
  34
  35         if (phys_addr < virt_to_phys(high_memory))
  36                 return phys_to_virt(phys_addr);
  37         if (phys_addr & ~PAGE_MASK)
  38                 return NULL;
  39         size = PAGE_ALIGN(size);
  40         if (!size || size > phys_addr + size)
  41                 return NULL;
  42         area = get_vm_area(size, VM_IOREMAP);
  43         if (!area)
  44                 return NULL;
  45         addr = area->addr;
  46         if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
  47                                phys_addr, __pgprot(flags))) {
  48                 vfree(addr);
  49                 return NULL;
  50         }
  51         return addr;
  52 }
  53
  54 void iounmap(void *addr)
  55 {
  56         if (addr > high_memory)
  57                 vfree(addr);
  58 }