arch/parisc/mm/ioremap.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * arch/parisc/mm/ioremap.c
   4  *
   5  * (C) Copyright 1995 1996 Linus Torvalds
   6  * (C) Copyright 2001-2006 Helge Deller <deller@gmx.de>
   7  * (C) Copyright 2005 Kyle McMartin <kyle@parisc-linux.org>
   8  */
   9
  10 #include <linux/vmalloc.h>
  11 #include <linux/errno.h>
  12 #include <linux/module.h>
  13 #include <linux/io.h>
  14 #include <asm/pgalloc.h>
  15
  16 /*
  17  * Generic mapping function (not visible outside):
  18  */
  19
  20 /*
  21  * Remap an arbitrary physical address space into the kernel virtual
  22  * address space.
  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, unsigned long size, unsigned long flags)
  29 {
  30         void __iomem *addr;
  31         struct vm_struct *area;
  32         unsigned long offset, last_addr;
  33         pgprot_t pgprot;
  34
  35 #ifdef CONFIG_EISA
  36         unsigned long end = phys_addr + size - 1;
  37         /* Support EISA addresses */
  38         if ((phys_addr >= 0x00080000 && end < 0x000fffff) ||
  39             (phys_addr >= 0x00500000 && end < 0x03bfffff)) {
  40                 phys_addr |= F_EXTEND(0xfc000000);
  41                 flags |= _PAGE_NO_CACHE;
  42         }
  43 #endif
  44
  45         /* Don't allow wraparound or zero size */
  46         last_addr = phys_addr + size - 1;
  47         if (!size || last_addr < phys_addr)
  48                 return NULL;
  49
  50         /*
  51          * Don't allow anybody to remap normal RAM that we're using..
  52          */
  53         if (phys_addr < virt_to_phys(high_memory)) {
  54                 char *t_addr, *t_end;
  55                 struct page *page;
  56
  57                 t_addr = __va(phys_addr);
  58                 t_end = t_addr + (size - 1);
  59
  60                 for (page = virt_to_page(t_addr);
  61                      page <= virt_to_page(t_end); page++) {
  62                         if(!PageReserved(page))
  63                                 return NULL;
  64                 }
  65         }
  66
  67         pgprot = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY |
  68                           _PAGE_ACCESSED | flags);
  69
  70         /*
  71          * Mappings have to be page-aligned
  72          */
  73         offset = phys_addr & ~PAGE_MASK;
  74         phys_addr &= PAGE_MASK;
  75         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
  76
  77         /*
  78          * Ok, go for it..
  79          */
  80         area = get_vm_area(size, VM_IOREMAP);
  81         if (!area)
  82                 return NULL;
  83
  84         addr = (void __iomem *) area->addr;
  85         if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
  86                                phys_addr, pgprot)) {
  87                 vfree(addr);
  88                 return NULL;
  89         }
  90
  91         return (void __iomem *) (offset + (char __iomem *)addr);
  92 }
  93 EXPORT_SYMBOL(__ioremap);
  94
  95 void iounmap(const volatile void __iomem *addr)
  96 {
  97         if (addr > high_memory)
  98                 return vfree((void *) (PAGE_MASK & (unsigned long __force) addr));
  99 }
 100 EXPORT_SYMBOL(iounmap);