arch/parisc/mm/ioremap.c

   1 /*
   2  * arch/parisc/mm/ioremap.c
   3  *
   4  * (C) Copyright 1995 1996 Linus Torvalds
   5  * (C) Copyright 2001-2006 Helge Deller <deller@gmx.de>
   6  * (C) Copyright 2005 Kyle McMartin <kyle@parisc-linux.org>
   7  */
   8
   9 #include <linux/vmalloc.h>
  10 #include <linux/errno.h>
  11 #include <linux/module.h>
  12 #include <asm/io.h>
  13 #include <asm/pgalloc.h>
  14 #include <asm/tlbflush.h>
  15 #include <asm/cacheflush.h>
  16
  17 static inline void
  18 remap_area_pte(pte_t *pte, unsigned long address, unsigned long size,
  19                unsigned long phys_addr, unsigned long flags)
  20 {
  21         unsigned long end, pfn;
  22         pgprot_t pgprot = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY |
  23                                    _PAGE_ACCESSED | flags);
  24
  25         address &= ~PMD_MASK;
  26
  27         end = address + size;
  28         if (end > PMD_SIZE)
  29                 end = PMD_SIZE;
  30
  31         BUG_ON(address >= end);
  32
  33         pfn = phys_addr >> PAGE_SHIFT;
  34         do {
  35                 BUG_ON(!pte_none(*pte));
  36
  37                 set_pte(pte, pfn_pte(pfn, pgprot));
  38
  39                 address += PAGE_SIZE;
  40                 pfn++;
  41                 pte++;
  42         } while (address && (address < end));
  43 }
  44
  45 static inline int
  46 remap_area_pmd(pmd_t *pmd, unsigned long address, unsigned long size,
  47                unsigned long phys_addr, unsigned long flags)
  48 {
  49         unsigned long end;
  50
  51         address &= ~PGDIR_MASK;
  52
  53         end = address + size;
  54         if (end > PGDIR_SIZE)
  55                 end = PGDIR_SIZE;
  56
  57         BUG_ON(address >= end);
  58
  59         phys_addr -= address;
  60         do {
  61                 pte_t *pte = pte_alloc_kernel(pmd, address);
  62                 if (!pte)
  63                         return -ENOMEM;
  64
  65                 remap_area_pte(pte, address, end - address,
  66                                address + phys_addr, flags);
  67
  68                 address = (address + PMD_SIZE) & PMD_MASK;
  69                 pmd++;
  70         } while (address && (address < end));
  71
  72         return 0;
  73 }
  74
  75 static int
  76 remap_area_pages(unsigned long address, unsigned long phys_addr,
  77                  unsigned long size, unsigned long flags)
  78 {
  79         pgd_t *dir;
  80         int error = 0;
  81         unsigned long end = address + size;
  82
  83         BUG_ON(address >= end);
  84
  85         phys_addr -= address;
  86         dir = pgd_offset_k(address);
  87
  88         flush_cache_all();
  89
  90         do {
  91                 pud_t *pud;
  92                 pmd_t *pmd;
  93
  94                 error = -ENOMEM;
  95                 pud = pud_alloc(&init_mm, dir, address);
  96                 if (!pud)
  97                         break;
  98
  99                 pmd = pmd_alloc(&init_mm, pud, address);
 100                 if (!pmd)
 101                         break;
 102
 103                 if (remap_area_pmd(pmd, address, end - address,
 104                                    phys_addr + address, flags))
 105                         break;
 106
 107                 error = 0;
 108                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
 109                 dir++;
 110         } while (address && (address < end));
 111
 112         flush_tlb_all();
 113
 114         return error;
 115 }
 116
 117 /*
 118  * Generic mapping function (not visible outside):
 119  */
 120
 121 /*
 122  * Remap an arbitrary physical address space into the kernel virtual
 123  * address space.
 124  *
 125  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 126  * have to convert them into an offset in a page-aligned mapping, but the
 127  * caller shouldn't need to know that small detail.
 128  */
 129 void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
 130 {
 131         void *addr;
 132         struct vm_struct *area;
 133         unsigned long offset, last_addr;
 134
 135 #ifdef CONFIG_EISA
 136         unsigned long end = phys_addr + size - 1;
 137         /* Support EISA addresses */
 138         if ((phys_addr >= 0x00080000 && end < 0x000fffff) ||
 139             (phys_addr >= 0x00500000 && end < 0x03bfffff)) {
 140                 phys_addr |= F_EXTEND(0xfc000000);
 141                 flags |= _PAGE_NO_CACHE;
 142         }
 143 #endif
 144
 145         /* Don't allow wraparound or zero size */
 146         last_addr = phys_addr + size - 1;
 147         if (!size || last_addr < phys_addr)
 148                 return NULL;
 149
 150         /*
 151          * Don't allow anybody to remap normal RAM that we're using..
 152          */
 153         if (phys_addr < virt_to_phys(high_memory)) {
 154                 char *t_addr, *t_end;
 155                 struct page *page;
 156
 157                 t_addr = __va(phys_addr);
 158                 t_end = t_addr + (size - 1);
 159
 160                 for (page = virt_to_page(t_addr);
 161                      page <= virt_to_page(t_end); page++) {
 162                         if(!PageReserved(page))
 163                                 return NULL;
 164                 }
 165         }
 166
 167         /*
 168          * Mappings have to be page-aligned
 169          */
 170         offset = phys_addr & ~PAGE_MASK;
 171         phys_addr &= PAGE_MASK;
 172         size = PAGE_ALIGN(last_addr) - phys_addr;
 173
 174         /*
 175          * Ok, go for it..
 176          */
 177         area = get_vm_area(size, VM_IOREMAP);
 178         if (!area)
 179                 return NULL;
 180
 181         addr = area->addr;
 182         if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
 183                 vfree(addr);
 184                 return NULL;
 185         }
 186
 187         return (void __iomem *) (offset + (char *)addr);
 188 }
 189 EXPORT_SYMBOL(__ioremap);
 190
 191 void iounmap(const volatile void __iomem *addr)
 192 {
 193         if (addr > high_memory)
 194                 return vfree((void *) (PAGE_MASK & (unsigned long __force) addr));
 195 }
 196 EXPORT_SYMBOL(iounmap);