release/src-rt-6.x/linux/linux-2.6/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/module.h>
  10 #include <asm/addrspace.h>
  11 #include <asm/byteorder.h>
  12 #include <linux/sched.h>
  13 #include <linux/vmalloc.h>
  14 #include <linux/hardirq.h>
  15 #include <linux/highmem.h>
  16 #include <asm/cacheflush.h>
  17 #include <asm/io.h>
  18 #include <asm/tlbflush.h>
  19
  20 static inline void remap_area_pte(pte_t * pte, unsigned long address,
  21         phys_t size, phys_t phys_addr, unsigned long flags)
  22 {
  23         phys_t end;
  24         unsigned long pfn;
  25         pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | __READABLE
  26                                    | __WRITEABLE | flags);
  27
  28         address &= ~PMD_MASK;
  29         end = address + size;
  30         if (end > PMD_SIZE)
  31                 end = PMD_SIZE;
  32         if (address >= end)
  33                 BUG();
  34         pfn = phys_addr >> PAGE_SHIFT;
  35         do {
  36                 if (!pte_none(*pte)) {
  37                         printk("remap_area_pte: page already exists\n");
  38                         BUG();
  39                 }
  40                 set_pte(pte, pfn_pte(pfn, pgprot));
  41                 address += PAGE_SIZE;
  42                 pfn++;
  43                 pte++;
  44         } while (address && (address < end));
  45 }
  46
  47 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address,
  48         phys_t size, phys_t phys_addr, unsigned long flags)
  49 {
  50         phys_t end;
  51
  52         address &= ~PGDIR_MASK;
  53         end = address + size;
  54         if (end > PGDIR_SIZE)
  55                 end = PGDIR_SIZE;
  56         phys_addr -= address;
  57         if (address >= end)
  58                 BUG();
  59         do {
  60                 pte_t * pte = pte_alloc_kernel(pmd, address);
  61                 if (!pte)
  62                         return -ENOMEM;
  63                 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
  64                 address = (address + PMD_SIZE) & PMD_MASK;
  65                 pmd++;
  66         } while (address && (address < end));
  67         return 0;
  68 }
  69
  70 static int remap_area_pages(unsigned long address, phys_t phys_addr,
  71         phys_t size, unsigned long flags)
  72 {
  73         int error;
  74         pgd_t * dir;
  75         unsigned long end = address + size;
  76
  77         phys_addr -= address;
  78         dir = pgd_offset(&init_mm, address);
  79         flush_cache_all();
  80         if (address >= end)
  81                 BUG();
  82         do {
  83                 pud_t *pud;
  84                 pmd_t *pmd;
  85
  86                 error = -ENOMEM;
  87                 pud = pud_alloc(&init_mm, dir, address);
  88                 if (!pud)
  89                         break;
  90                 pmd = pmd_alloc(&init_mm, pud, address);
  91                 if (!pmd)
  92                         break;
  93                 if (remap_area_pmd(pmd, address, end - address,
  94                                          phys_addr + address, flags))
  95                         break;
  96                 error = 0;
  97                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
  98                 dir++;
  99         } while (address && (address < end));
 100         flush_tlb_all();
 101         return error;
 102 }
 103
 104 /*
 105  * Generic mapping function (not visible outside):
 106  */
 107
 108 /*
 109  * Remap an arbitrary physical address space into the kernel virtual
 110  * address space. Needed when the kernel wants to access high addresses
 111  * directly.
 112  *
 113  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 114  * have to convert them into an offset in a page-aligned mapping, but the
 115  * caller shouldn't need to know that small detail.
 116  */
 117
 118 #define IS_LOW512(addr) (!((phys_t)(addr) & (phys_t) ~0x1fffffffULL))
 119
 120 void *kmap_atomic_pfn_prot(unsigned long pfn, enum km_type type, pgprot_t prot)
 121 {
 122         pgprot_t old_kmap_prot = kmap_prot;
 123         void * vaddr;
 124
 125         kmap_prot =  prot;
 126         vaddr = kmap_atomic_pfn(pfn, type);
 127         kmap_prot = old_kmap_prot;
 128         return vaddr;
 129 }
 130
 131 void __iomem * __ioremap(phys_t phys_addr, phys_t size, unsigned long flags)
 132 {
 133         struct vm_struct * area;
 134         unsigned long offset;
 135         phys_t last_addr;
 136         void * addr;
 137
 138         phys_addr = fixup_bigphys_addr(phys_addr, size);
 139
 140         /* Don't allow wraparound or zero size */
 141         last_addr = phys_addr + size - 1;
 142         if (!size || last_addr < phys_addr)
 143                 return NULL;
 144
 145         /*
 146          * Map uncached objects in the low 512mb of address space using KSEG1,
 147          * otherwise map using page tables.
 148          */
 149         if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) &&
 150             flags == _CACHE_UNCACHED)
 151                 return (void __iomem *) CKSEG1ADDR(phys_addr);
 152
 153         /*
 154          * Don't allow anybody to remap normal RAM that we're using..
 155          */
 156         if (phys_addr < virt_to_phys(high_memory)) {
 157                 char *t_addr, *t_end;
 158                 struct page *page;
 159
 160                 t_addr = __va(phys_addr);
 161                 t_end = t_addr + (size - 1);
 162
 163                 for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
 164                         if(!PageReserved(page))
 165                                 return NULL;
 166         }
 167
 168         /*
 169          * Mappings have to be page-aligned
 170          */
 171         offset = phys_addr & ~PAGE_MASK;
 172         phys_addr &= PAGE_MASK;
 173         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
 174
 175         /* If we are in interrupt/Bottom half context, try to use fixed temporary
 176          * map, which we can get atomically. However we are limited by one page only.
 177          */
 178         if (in_interrupt() && (size <= PAGE_SIZE))
 179                 return (void __iomem *) (kmap_atomic_pfn_prot(phys_addr >> PAGE_SHIFT, KM_PCIE, PAGE_KERNEL_UNCACHED) + offset);
 180
 181         /*
 182          * Ok, go for it..
 183          */
 184         area = get_vm_area(size, VM_IOREMAP);
 185
 186         if (!area)
 187                 return NULL;
 188         addr = area->addr;
 189         if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
 190                 vunmap(addr);
 191                 return NULL;
 192         }
 193
 194         return (void __iomem *) (offset + (char *)addr);
 195 }
 196
 197 #define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
 198
 199 void __iounmap(const volatile void __iomem *addr)
 200 {
 201         struct vm_struct *p;
 202
 203         if (IS_KSEG1(addr))
 204                 return;
 205
 206         if (in_interrupt()) {
 207                 kunmap_atomic((void *)addr, KM_PCIE);
 208                 return;
 209         }
 210
 211         p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));
 212         if (!p)
 213                 printk(KERN_ERR "iounmap: bad address %p\n", addr);
 214
 215         kfree(p);
 216 }
 217
 218 EXPORT_SYMBOL(__ioremap);
 219 EXPORT_SYMBOL(__iounmap);