LXR linux/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 2001-2019 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 <linux/mm.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 */
  28void __iomem *ioremap(unsigned long phys_addr, unsigned long size)
  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#endif
  42
  43        /* Don't allow wraparound or zero size */
  44        last_addr = phys_addr + size - 1;
  45        if (!size || last_addr < phys_addr)
  46                return NULL;
  47
  48        /*
  49         * Don't allow anybody to remap normal RAM that we're using..
  50         */
  51        if (phys_addr < virt_to_phys(high_memory)) {
  52                char *t_addr, *t_end;
  53                struct page *page;
  54
  55                t_addr = __va(phys_addr);
  56                t_end = t_addr + (size - 1);
  57           
  58                for (page = virt_to_page(t_addr); 
  59                     page <= virt_to_page(t_end); page++) {
  60                        if(!PageReserved(page))
  61                                return NULL;
  62                }
  63        }
  64
  65        pgprot = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY |
  66                          _PAGE_ACCESSED | _PAGE_NO_CACHE);
  67
  68        /*
  69         * Mappings have to be page-aligned
  70         */
  71        offset = phys_addr & ~PAGE_MASK;
  72        phys_addr &= PAGE_MASK;
  73        size = PAGE_ALIGN(last_addr + 1) - phys_addr;
  74
  75        /*
  76         * Ok, go for it..
  77         */
  78        area = get_vm_area(size, VM_IOREMAP);
  79        if (!area)
  80                return NULL;
  81
  82        addr = (void __iomem *) area->addr;
  83        if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
  84                               phys_addr, pgprot)) {
  85                vunmap(addr);
  86                return NULL;
  87        }
  88
  89        return (void __iomem *) (offset + (char __iomem *)addr);
  90}
  91EXPORT_SYMBOL(ioremap);
  92
  93void iounmap(const volatile void __iomem *io_addr)
  94{
  95        unsigned long addr = (unsigned long)io_addr & PAGE_MASK;
  96
  97        if (is_vmalloc_addr((void *)addr))
  98                vunmap((void *)addr);
  99}
 100EXPORT_SYMBOL(iounmap);
 101