arch/parisc/mm/ioremap.c

   1 /*
   2  * arch/parisc/mm/ioremap.c
   3  *
   4  * Re-map IO memory to kernel address space so that we can access it.
   5  * This is needed for high PCI addresses that aren't mapped in the
   6  * 640k-1MB IO memory area on PC's
   7  *
   8  * (C) Copyright 1995 1996 Linus Torvalds
   9  * (C) Copyright 2001 Helge Deller <deller@gmx.de>
  10  */
  11
  12 #include <linux/vmalloc.h>
  13 #include <linux/errno.h>
  14 #include <linux/module.h>
  15 #include <asm/io.h>
  16 #include <asm/pgalloc.h>
  17
  18 static inline void 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;
  22
  23         address &= ~PMD_MASK;
  24         end = address + size;
  25         if (end > PMD_SIZE)
  26                 end = PMD_SIZE;
  27         if (address >= end)
  28                 BUG();
  29         do {
  30                 if (!pte_none(*pte)) {
  31                         printk(KERN_ERR "remap_area_pte: page already exists\n");
  32                         BUG();
  33                 }
  34                 set_pte(pte, mk_pte_phys(phys_addr, __pgprot(_PAGE_PRESENT | _PAGE_RW |
  35                                         _PAGE_DIRTY | _PAGE_ACCESSED | flags)));
  36                 address += PAGE_SIZE;
  37                 phys_addr += PAGE_SIZE;
  38                 pte++;
  39         } while (address && (address < end));
  40 }
  41
  42 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
  43         unsigned long phys_addr, unsigned long flags)
  44 {
  45         unsigned long end;
  46
  47         address &= ~PGDIR_MASK;
  48         end = address + size;
  49         if (end > PGDIR_SIZE)
  50                 end = PGDIR_SIZE;
  51         phys_addr -= address;
  52         if (address >= end)
  53                 BUG();
  54         do {
  55                 pte_t * pte = pte_alloc_kernel(NULL, pmd, address);
  56                 if (!pte)
  57                         return -ENOMEM;
  58                 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
  59                 address = (address + PMD_SIZE) & PMD_MASK;
  60                 pmd++;
  61         } while (address && (address < end));
  62         return 0;
  63 }
  64
  65 #if (USE_HPPA_IOREMAP)
  66 static int remap_area_pages(unsigned long address, unsigned long phys_addr,
  67                                  unsigned long size, unsigned long flags)
  68 {
  69         int error;
  70         pgd_t * dir;
  71         unsigned long end = address + size;
  72
  73         phys_addr -= address;
  74         dir = pgd_offset(&init_mm, address);
  75         flush_cache_all();
  76         if (address >= end)
  77                 BUG();
  78         spin_lock(&init_mm.page_table_lock);
  79         do {
  80                 pmd_t *pmd;
  81                 pmd = pmd_alloc(dir, address);
  82                 error = -ENOMEM;
  83                 if (!pmd)
  84                         break;
  85                 if (remap_area_pmd(pmd, address, end - address,
  86                                          phys_addr + address, flags))
  87                         break;
  88                 error = 0;
  89                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
  90                 dir++;
  91         } while (address && (address < end));
  92         spin_unlock(&init_mm.page_table_lock);
  93         flush_tlb_all();
  94         return error;
  95 }
  96 #endif /* USE_HPPA_IOREMAP */
  97
  98 #ifdef CONFIG_DEBUG_IOREMAP
  99 static unsigned long last = 0;
 100
 101 void gsc_bad_addr(unsigned long addr)
 102 {
 103         if (time_after(jiffies, last + HZ*10)) {
 104                 printk("gsc_foo() called with bad address 0x%lx\n", addr);
 105                 dump_stack();
 106                 last = jiffies;
 107         }
 108 }
 109 EXPORT_SYMBOL(gsc_bad_addr);
 110
 111 void __raw_bad_addr(const volatile void __iomem *addr)
 112 {
 113         if (time_after(jiffies, last + HZ*10)) {
 114                 printk("__raw_foo() called with bad address 0x%p\n", addr);
 115                 dump_stack();
 116                 last = jiffies;
 117         }
 118 }
 119 EXPORT_SYMBOL(__raw_bad_addr);
 120 #endif
 121
 122 /*
 123  * Generic mapping function (not visible outside):
 124  */
 125
 126 /*
 127  * Remap an arbitrary physical address space into the kernel virtual
 128  * address space. Needed when the kernel wants to access high addresses
 129  * directly.
 130  *
 131  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 132  * have to convert them into an offset in a page-aligned mapping, but the
 133  * caller shouldn't need to know that small detail.
 134  */
 135 void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
 136 {
 137 #if !(USE_HPPA_IOREMAP)
 138
 139         unsigned long end = phys_addr + size - 1;
 140         /* Support EISA addresses */
 141         if ((phys_addr >= 0x00080000 && end < 0x000fffff)
 142                         || (phys_addr >= 0x00500000 && end < 0x03bfffff)) {
 143                 phys_addr |= 0xfc000000;
 144         }
 145
 146 #ifdef CONFIG_DEBUG_IOREMAP
 147         return (void __iomem *)(phys_addr - (0x1UL << NYBBLE_SHIFT));
 148 #else
 149         return (void __iomem *)phys_addr;
 150 #endif
 151
 152 #else
 153         void * addr;
 154         struct vm_struct * area;
 155         unsigned long offset, last_addr;
 156
 157         /* Don't allow wraparound or zero size */
 158         last_addr = phys_addr + size - 1;
 159         if (!size || last_addr < phys_addr)
 160                 return NULL;
 161
 162         /*
 163          * Don't allow anybody to remap normal RAM that we're using..
 164          */
 165         if (phys_addr < virt_to_phys(high_memory)) {
 166                 char *t_addr, *t_end;
 167                 struct page *page;
 168
 169                 t_addr = __va(phys_addr);
 170                 t_end = t_addr + (size - 1);
 171
 172                 for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
 173                         if(!PageReserved(page))
 174                                 return NULL;
 175         }
 176
 177         /*
 178          * Mappings have to be page-aligned
 179          */
 180         offset = phys_addr & ~PAGE_MASK;
 181         phys_addr &= PAGE_MASK;
 182         size = PAGE_ALIGN(last_addr) - phys_addr;
 183
 184         /*
 185          * Ok, go for it..
 186          */
 187         area = get_vm_area(size, VM_IOREMAP);
 188         if (!area)
 189                 return NULL;
 190         addr = area->addr;
 191         if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
 192                 vfree(addr);
 193                 return NULL;
 194         }
 195         return (void __iomem *) (offset + (char *)addr);
 196 #endif
 197 }
 198
 199 void iounmap(void __iomem *addr)
 200 {
 201 #if !(USE_HPPA_IOREMAP)
 202         return;
 203 #else
 204         if (addr > high_memory)
 205                 return vfree((void *) (PAGE_MASK & (unsigned long __force) addr));
 206 #endif
 207 }