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 <asm/io.h>
  15 #include <asm/pgalloc.h>
  16
  17 static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,
  18         unsigned long phys_addr, unsigned long flags)
  19 {
  20         unsigned long end;
  21
  22         address &= ~PMD_MASK;
  23         end = address + size;
  24         if (end > PMD_SIZE)
  25                 end = PMD_SIZE;
  26         if (address >= end)
  27                 BUG();
  28         do {
  29                 if (!pte_none(*pte)) {
  30                         printk(KERN_ERR "remap_area_pte: page already exists\n");
  31                         BUG();
  32                 }
  33                 set_pte(pte, mk_pte_phys(phys_addr, __pgprot(_PAGE_PRESENT | _PAGE_RW |
  34                                         _PAGE_DIRTY | _PAGE_ACCESSED | flags)));
  35                 address += PAGE_SIZE;
  36                 phys_addr += PAGE_SIZE;
  37                 pte++;
  38         } while (address && (address < end));
  39 }
  40
  41 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
  42         unsigned long phys_addr, unsigned long flags)
  43 {
  44         unsigned long end;
  45
  46         address &= ~PGDIR_MASK;
  47         end = address + size;
  48         if (end > PGDIR_SIZE)
  49                 end = PGDIR_SIZE;
  50         phys_addr -= address;
  51         if (address >= end)
  52                 BUG();
  53         do {
  54                 pte_t * pte = pte_alloc_kernel(NULL, pmd, address);
  55                 if (!pte)
  56                         return -ENOMEM;
  57                 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
  58                 address = (address + PMD_SIZE) & PMD_MASK;
  59                 pmd++;
  60         } while (address && (address < end));
  61         return 0;
  62 }
  63
  64 #if (USE_HPPA_IOREMAP)
  65 static int remap_area_pages(unsigned long address, unsigned long phys_addr,
  66                                  unsigned long size, unsigned long flags)
  67 {
  68         int error;
  69         pgd_t * dir;
  70         unsigned long end = address + size;
  71
  72         phys_addr -= address;
  73         dir = pgd_offset(&init_mm, address);
  74         flush_cache_all();
  75         if (address >= end)
  76                 BUG();
  77         spin_lock(&init_mm.page_table_lock);
  78         do {
  79                 pmd_t *pmd;
  80                 pmd = pmd_alloc(dir, address);
  81                 error = -ENOMEM;
  82                 if (!pmd)
  83                         break;
  84                 if (remap_area_pmd(pmd, address, end - address,
  85                                          phys_addr + address, flags))
  86                         break;
  87                 error = 0;
  88                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
  89                 dir++;
  90         } while (address && (address < end));
  91         spin_unlock(&init_mm.page_table_lock);
  92         flush_tlb_all();
  93         return error;
  94 }
  95 #endif /* USE_HPPA_IOREMAP */
  96
  97 /*
  98  * Generic mapping function (not visible outside):
  99  */
 100
 101 /*
 102  * Remap an arbitrary physical address space into the kernel virtual
 103  * address space. Needed when the kernel wants to access high addresses
 104  * directly.
 105  *
 106  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 107  * have to convert them into an offset in a page-aligned mapping, but the
 108  * caller shouldn't need to know that small detail.
 109  */
 110 void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
 111 {
 112 #if !(USE_HPPA_IOREMAP)
 113
 114         unsigned long end = phys_addr + size - 1;
 115         /* Support EISA addresses */
 116         if ((phys_addr >= 0x00080000 && end < 0x000fffff)
 117                         || (phys_addr >= 0x00500000 && end < 0x03bfffff)) {
 118                 phys_addr |= 0xfc000000;
 119         }
 120
 121         return (void *)phys_addr;
 122
 123 #else
 124         void * addr;
 125         struct vm_struct * area;
 126         unsigned long offset, last_addr;
 127
 128         /* Don't allow wraparound or zero size */
 129         last_addr = phys_addr + size - 1;
 130         if (!size || last_addr < phys_addr)
 131                 return NULL;
 132
 133         /*
 134          * Don't allow anybody to remap normal RAM that we're using..
 135          */
 136         if (phys_addr < virt_to_phys(high_memory)) {
 137                 char *t_addr, *t_end;
 138                 struct page *page;
 139
 140                 t_addr = __va(phys_addr);
 141                 t_end = t_addr + (size - 1);
 142
 143                 for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
 144                         if(!PageReserved(page))
 145                                 return NULL;
 146         }
 147
 148         /*
 149          * Mappings have to be page-aligned
 150          */
 151         offset = phys_addr & ~PAGE_MASK;
 152         phys_addr &= PAGE_MASK;
 153         size = PAGE_ALIGN(last_addr) - phys_addr;
 154
 155         /*
 156          * Ok, go for it..
 157          */
 158         area = get_vm_area(size, VM_IOREMAP);
 159         if (!area)
 160                 return NULL;
 161         addr = area->addr;
 162         if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
 163                 vfree(addr);
 164                 return NULL;
 165         }
 166         return (void *) (offset + (char *)addr);
 167 #endif
 168 }
 169
 170 void iounmap(void *addr)
 171 {
 172 #if !(USE_HPPA_IOREMAP)
 173         return;
 174 #else
 175         if (addr > high_memory)
 176                 return vfree((void *) (PAGE_MASK & (unsigned long) addr));
 177 #endif
 178 }