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 extern 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(&init_mm, 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         spin_lock(&init_mm.page_table_lock);
  78         do {
  79                 pud_t *pud;
  80                 pmd_t *pmd;
  81
  82                 error = -ENOMEM;
  83                 pud = pud_alloc(&init_mm, dir, address);
  84                 if (!pud)
  85                         break;
  86                 pmd = pmd_alloc(&init_mm, pud, address);
  87
  88                 if (!pmd)
  89                         break;
  90                 if (remap_area_pmd(pmd, address, end - address,
  91                                    phys_addr + address, prot))
  92                         break;
  93                 error = 0;
  94                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
  95                 dir++;
  96         } while (address && (address < end));
  97         spin_unlock(&init_mm.page_table_lock);
  98         flush_tlb_all();
  99         return error;
 100 }
 101
 102 /*
 103  * Generic mapping function (not visible outside):
 104  */
 105
 106 /*
 107  * Remap an arbitrary physical address space into the kernel virtual
 108  * address space. Needed when the kernel wants to access high addresses
 109  * directly.
 110  *
 111  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 112  * have to convert them into an offset in a page-aligned mapping, but the
 113  * caller shouldn't need to know that small detail.
 114  */
 115 void __iomem * __ioremap_prot(unsigned long phys_addr, unsigned long size, pgprot_t prot)
 116 {
 117         void __iomem * addr;
 118         struct vm_struct * area;
 119         unsigned long offset, last_addr;
 120
 121         /* Don't allow wraparound or zero size */
 122         last_addr = phys_addr + size - 1;
 123         if (!size || last_addr < phys_addr)
 124                 return NULL;
 125
 126         /*
 127          * Mappings have to be page-aligned
 128          */
 129         offset = phys_addr & ~PAGE_MASK;
 130         phys_addr &= PAGE_MASK;
 131         size = PAGE_ALIGN(last_addr+1) - phys_addr;
 132
 133         /*
 134          * Ok, go for it..
 135          */
 136         area = get_vm_area(size, VM_IOREMAP);
 137         if (!area)
 138                 return NULL;
 139         addr = (void __iomem *)area->addr;
 140         if (remap_area_pages((unsigned long) addr, phys_addr, size, prot)) {
 141                 vfree((void __force *)addr);
 142                 return NULL;
 143         }
 144         return (void __iomem *) (offset + (char __iomem *)addr);
 145 }
 146
 147 void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
 148 {
 149         return __ioremap_prot(phys_addr, size,
 150                               __pgprot(_PAGE_PRESENT | __READABLE |
 151                                        __WRITEABLE | _PAGE_GLOBAL |
 152                                        _PAGE_KERNEL | flags));
 153 }
 154
 155 /**
 156  * ioremap_nocache     -   map bus memory into CPU space
 157  * @offset:    bus address of the memory
 158  * @size:      size of the resource to map
 159  *
 160  * Must be freed with iounmap.
 161  */
 162
 163 void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
 164 {
 165         return __ioremap(phys_addr | MEM_NON_CACHEABLE, size, 0);
 166 }
 167
 168 void iounmap(volatile void __iomem *addr)
 169 {
 170         if (addr > high_memory)
 171                 return vfree((void *) (PAGE_MASK & (unsigned long) addr));
 172 }