LXR linux/arch/mips/mm/ioremap.c

   1/*
   2 * This file is subject to the terms and conditions of the GNU General Public
   3 * License.  See the file "COPYING" in the main directory of this archive
   4 * for more details.
   5 *
   6 * (C) Copyright 1995 1996 Linus Torvalds
   7 * (C) Copyright 2001, 2002 Ralf Baechle
   8 */
   9#include <linux/export.h>
  10#include <asm/addrspace.h>
  11#include <asm/byteorder.h>
  12#include <linux/ioport.h>
  13#include <linux/sched.h>
  14#include <linux/slab.h>
  15#include <linux/vmalloc.h>
  16#include <linux/mm_types.h>
  17#include <linux/io.h>
  18#include <asm/cacheflush.h>
  19#include <asm/tlbflush.h>
  20#include <ioremap.h>
  21
  22#define IS_LOW512(addr) (!((phys_addr_t)(addr) & (phys_addr_t) ~0x1fffffffULL))
  23#define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
  24
  25static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,
  26                               void *arg)
  27{
  28        unsigned long i;
  29
  30        for (i = 0; i < nr_pages; i++) {
  31                if (pfn_valid(start_pfn + i) &&
  32                    !PageReserved(pfn_to_page(start_pfn + i)))
  33                        return 1;
  34        }
  35
  36        return 0;
  37}
  38
  39/*
  40 * ioremap_prot     -   map bus memory into CPU space
  41 * @phys_addr:    bus address of the memory
  42 * @size:      size of the resource to map
  43 *
  44 * ioremap_prot gives the caller control over cache coherency attributes (CCA)
  45 */
  46void __iomem *ioremap_prot(phys_addr_t phys_addr, unsigned long size,
  47                unsigned long prot_val)
  48{
  49        unsigned long flags = prot_val & _CACHE_MASK;
  50        unsigned long offset, pfn, last_pfn;
  51        struct vm_struct *area;
  52        phys_addr_t last_addr;
  53        unsigned long vaddr;
  54        void __iomem *cpu_addr;
  55
  56        cpu_addr = plat_ioremap(phys_addr, size, flags);
  57        if (cpu_addr)
  58                return cpu_addr;
  59
  60        phys_addr = fixup_bigphys_addr(phys_addr, size);
  61
  62        /* Don't allow wraparound or zero size */
  63        last_addr = phys_addr + size - 1;
  64        if (!size || last_addr < phys_addr)
  65                return NULL;
  66
  67        /*
  68         * Map uncached objects in the low 512mb of address space using KSEG1,
  69         * otherwise map using page tables.
  70         */
  71        if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) &&
  72            flags == _CACHE_UNCACHED)
  73                return (void __iomem *) CKSEG1ADDR(phys_addr);
  74
  75        /*
  76         * Don't allow anybody to remap RAM that may be allocated by the page
  77         * allocator, since that could lead to races & data clobbering.
  78         */
  79        pfn = PFN_DOWN(phys_addr);
  80        last_pfn = PFN_DOWN(last_addr);
  81        if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
  82                                  __ioremap_check_ram) == 1) {
  83                WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n",
  84                          &phys_addr, &last_addr);
  85                return NULL;
  86        }
  87
  88        /*
  89         * Mappings have to be page-aligned
  90         */
  91        offset = phys_addr & ~PAGE_MASK;
  92        phys_addr &= PAGE_MASK;
  93        size = PAGE_ALIGN(last_addr + 1) - phys_addr;
  94
  95        /*
  96         * Ok, go for it..
  97         */
  98        area = get_vm_area(size, VM_IOREMAP);
  99        if (!area)
 100                return NULL;
 101        vaddr = (unsigned long)area->addr;
 102
 103        flags |= _PAGE_GLOBAL | _PAGE_PRESENT | __READABLE | __WRITEABLE;
 104        if (ioremap_page_range(vaddr, vaddr + size, phys_addr,
 105                        __pgprot(flags))) {
 106                free_vm_area(area);
 107                return NULL;
 108        }
 109
 110        return (void __iomem *)(vaddr + offset);
 111}
 112EXPORT_SYMBOL(ioremap_prot);
 113
 114void iounmap(const volatile void __iomem *addr)
 115{
 116        if (!plat_iounmap(addr) && !IS_KSEG1(addr))
 117                vunmap((void *)((unsigned long)addr & PAGE_MASK));
 118}
 119EXPORT_SYMBOL(iounmap);
 120