arch/m32r/mm/ioremap.c

   1 /*
   2  *  linux/arch/m32r/mm/ioremap.c
   3  *
   4  *  Copyright (c) 2001, 2002  Hiroyuki Kondo
   5  *
   6  *  Taken from mips version.
   7  *    (C) Copyright 1995 1996 Linus Torvalds
   8  *    (C) Copyright 2001 Ralf Baechle
   9  */
  10
  11 /*
  12  * This file is subject to the terms and conditions of the GNU General Public
  13  * License.  See the file "COPYING" in the main directory of this archive
  14  * for more details.
  15  *
  16  */
  17
  18 #include <linux/module.h>
  19 #include <asm/addrspace.h>
  20 #include <asm/byteorder.h>
  21
  22 #include <linux/vmalloc.h>
  23 #include <asm/io.h>
  24 #include <asm/pgalloc.h>
  25 #include <asm/cacheflush.h>
  26 #include <asm/tlbflush.h>
  27
  28 static inline void
  29 remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,
  30                unsigned long phys_addr, unsigned long flags)
  31 {
  32         unsigned long end;
  33         unsigned long pfn;
  34         pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | _PAGE_READ
  35                                    | _PAGE_WRITE | flags);
  36
  37         address &= ~PMD_MASK;
  38         end = address + size;
  39         if (end > PMD_SIZE)
  40                 end = PMD_SIZE;
  41         if (address >= end)
  42                 BUG();
  43         pfn = phys_addr >> PAGE_SHIFT;
  44         do {
  45                 if (!pte_none(*pte)) {
  46                         printk("remap_area_pte: page already exists\n");
  47                         BUG();
  48                 }
  49                 set_pte(pte, pfn_pte(pfn, pgprot));
  50                 address += PAGE_SIZE;
  51                 pfn++;
  52                 pte++;
  53         } while (address && (address < end));
  54 }
  55
  56 static inline int
  57 remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
  58                unsigned long phys_addr, unsigned long flags)
  59 {
  60         unsigned long end;
  61
  62         address &= ~PGDIR_MASK;
  63         end = address + size;
  64         if (end > PGDIR_SIZE)
  65                 end = PGDIR_SIZE;
  66         phys_addr -= address;
  67         if (address >= end)
  68                 BUG();
  69         do {
  70                 pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
  71                 if (!pte)
  72                         return -ENOMEM;
  73                 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
  74                 address = (address + PMD_SIZE) & PMD_MASK;
  75                 pmd++;
  76         } while (address && (address < end));
  77         return 0;
  78 }
  79
  80 static int
  81 remap_area_pages(unsigned long address, unsigned long phys_addr,
  82                  unsigned long size, unsigned long flags)
  83 {
  84         int error;
  85         pgd_t * dir;
  86         unsigned long end = address + size;
  87
  88         phys_addr -= address;
  89         dir = pgd_offset(&init_mm, address);
  90         flush_cache_all();
  91         if (address >= end)
  92                 BUG();
  93         spin_lock(&init_mm.page_table_lock);
  94         do {
  95                 pmd_t *pmd;
  96                 pmd = pmd_alloc(&init_mm, dir, address);
  97                 error = -ENOMEM;
  98                 if (!pmd)
  99                         break;
 100                 if (remap_area_pmd(pmd, address, end - address,
 101                                          phys_addr + address, flags))
 102                         break;
 103                 error = 0;
 104                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
 105                 dir++;
 106         } while (address && (address < end));
 107         spin_unlock(&init_mm.page_table_lock);
 108         flush_tlb_all();
 109         return error;
 110 }
 111
 112 /*
 113  * Generic mapping function (not visible outside):
 114  */
 115
 116 /*
 117  * Remap an arbitrary physical address space into the kernel virtual
 118  * address space. Needed when the kernel wants to access high addresses
 119  * directly.
 120  *
 121  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 122  * have to convert them into an offset in a page-aligned mapping, but the
 123  * caller shouldn't need to know that small detail.
 124  */
 125
 126 #define IS_LOW512(addr) (!((unsigned long)(addr) & ~0x1fffffffUL))
 127
 128 void __iomem *
 129 __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
 130 {
 131         void __iomem * addr;
 132         struct vm_struct * area;
 133         unsigned long offset, last_addr;
 134
 135         /* Don't allow wraparound or zero size */
 136         last_addr = phys_addr + size - 1;
 137         if (!size || last_addr < phys_addr)
 138                 return NULL;
 139
 140         /*
 141          * Map objects in the low 512mb of address space using KSEG1, otherwise
 142          * map using page tables.
 143          */
 144         if (IS_LOW512(phys_addr) && IS_LOW512(phys_addr + size - 1))
 145                 return (void *) KSEG1ADDR(phys_addr);
 146
 147         /*
 148          * Don't allow anybody to remap normal RAM that we're using..
 149          */
 150         if (phys_addr < virt_to_phys(high_memory)) {
 151                 char *t_addr, *t_end;
 152                 struct page *page;
 153
 154                 t_addr = __va(phys_addr);
 155                 t_end = t_addr + (size - 1);
 156
 157                 for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
 158                         if(!PageReserved(page))
 159                                 return NULL;
 160         }
 161
 162         /*
 163          * Mappings have to be page-aligned
 164          */
 165         offset = phys_addr & ~PAGE_MASK;
 166         phys_addr &= PAGE_MASK;
 167         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
 168
 169         /*
 170          * Ok, go for it..
 171          */
 172         area = get_vm_area(size, VM_IOREMAP);
 173         if (!area)
 174                 return NULL;
 175         area->phys_addr = phys_addr;
 176         addr = (void __iomem *) area->addr;
 177         if (remap_area_pages((unsigned long)addr, phys_addr, size, flags)) {
 178                 vunmap((void __force *) addr);
 179                 return NULL;
 180         }
 181
 182         return (void __iomem *) (offset + (char __iomem *)addr);
 183 }
 184
 185 #define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == KSEG1)
 186
 187 void iounmap(volatile void __iomem *addr)
 188 {
 189         if (!IS_KSEG1(addr))
 190                 vfree((void *) (PAGE_MASK & (unsigned long) addr));
 191 }
 192