arch/cris/mm/ioremap.c

   1 /*
   2  * arch/cris/mm/ioremap.c
   3  *
   4  * Re-map IO memory to kernel address space so that we can access it.
   5  * Needed for memory-mapped I/O devices mapped outside our normal DRAM
   6  * window (that is, all memory-mapped I/O devices).
   7  *
   8  * (C) Copyright 1995 1996 Linus Torvalds
   9  * CRIS-port by Axis Communications AB
  10  */
  11
  12 #include <linux/vmalloc.h>
  13 #include <asm/io.h>
  14 #include <asm/pgalloc.h>
  15 #include <asm/cacheflush.h>
  16 #include <asm/tlbflush.h>
  17 #include <asm/arch/memmap.h>
  18
  19 static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,
  20         unsigned long phys_addr, pgprot_t prot)
  21 {
  22         unsigned long end;
  23
  24         address &= ~PMD_MASK;
  25         end = address + size;
  26         if (end > PMD_SIZE)
  27                 end = PMD_SIZE;
  28         if (address >= end)
  29                 BUG();
  30         do {
  31                 if (!pte_none(*pte)) {
  32                         printk("remap_area_pte: page already exists\n");
  33                         BUG();
  34                 }
  35                 set_pte(pte, mk_pte_phys(phys_addr, prot));
  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, pgprot_t prot)
  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(pmd, address);
  56                 if (!pte)
  57                         return -ENOMEM;
  58                 remap_area_pte(pte, address, end - address, address + phys_addr, prot);
  59                 address = (address + PMD_SIZE) & PMD_MASK;
  60                 pmd++;
  61         } while (address && (address < end));
  62         return 0;
  63 }
  64
  65 static int remap_area_pages(unsigned long address, unsigned long phys_addr,
  66                                  unsigned long size, pgprot_t prot)
  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         do {
  78                 pud_t *pud;
  79                 pmd_t *pmd;
  80
  81                 error = -ENOMEM;
  82                 pud = pud_alloc(&init_mm, dir, address);
  83                 if (!pud)
  84                         break;
  85                 pmd = pmd_alloc(&init_mm, pud, address);
  86
  87                 if (!pmd)
  88                         break;
  89                 if (remap_area_pmd(pmd, address, end - address,
  90                                    phys_addr + address, prot))
  91                         break;
  92                 error = 0;
  93                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
  94                 dir++;
  95         } while (address && (address < end));
  96         flush_tlb_all();
  97         return error;
  98 }
  99
 100 /*
 101  * Generic mapping function (not visible outside):
 102  */
 103
 104 /*
 105  * Remap an arbitrary physical address space into the kernel virtual
 106  * address space. Needed when the kernel wants to access high addresses
 107  * directly.
 108  *
 109  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 110  * have to convert them into an offset in a page-aligned mapping, but the
 111  * caller shouldn't need to know that small detail.
 112  */
 113 void __iomem * __ioremap_prot(unsigned long phys_addr, unsigned long size, pgprot_t prot)
 114 {
 115         void __iomem * addr;
 116         struct vm_struct * area;
 117         unsigned long offset, last_addr;
 118
 119         /* Don't allow wraparound or zero size */
 120         last_addr = phys_addr + size - 1;
 121         if (!size || last_addr < phys_addr)
 122                 return NULL;
 123
 124         /*
 125          * Mappings have to be page-aligned
 126          */
 127         offset = phys_addr & ~PAGE_MASK;
 128         phys_addr &= PAGE_MASK;
 129         size = PAGE_ALIGN(last_addr+1) - phys_addr;
 130
 131         /*
 132          * Ok, go for it..
 133          */
 134         area = get_vm_area(size, VM_IOREMAP);
 135         if (!area)
 136                 return NULL;
 137         addr = (void __iomem *)area->addr;
 138         if (remap_area_pages((unsigned long) addr, phys_addr, size, prot)) {
 139                 vfree((void __force *)addr);
 140                 return NULL;
 141         }
 142         return (void __iomem *) (offset + (char __iomem *)addr);
 143 }
 144
 145 void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
 146 {
 147         return __ioremap_prot(phys_addr, size,
 148                               __pgprot(_PAGE_PRESENT | __READABLE |
 149                                        __WRITEABLE | _PAGE_GLOBAL |
 150                                        _PAGE_KERNEL | flags));
 151 }
 152
 153 /**
 154  * ioremap_nocache     -   map bus memory into CPU space
 155  * @offset:    bus address of the memory
 156  * @size:      size of the resource to map
 157  *
 158  * Must be freed with iounmap.
 159  */
 160
 161 void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
 162 {
 163         return __ioremap(phys_addr | MEM_NON_CACHEABLE, size, 0);
 164 }
 165
 166 void iounmap(volatile void __iomem *addr)
 167 {
 168         if (addr > high_memory)
 169                 return vfree((void *) (PAGE_MASK & (unsigned long) addr));
 170 }