arch/sparc/mm/generic.c

   1 /* $Id: generic.c,v 1.14 2001/12/21 04:56:15 davem Exp $
   2  * generic.c: Generic Sparc mm routines that are not dependent upon
   3  *            MMU type but are Sparc specific.
   4  *
   5  * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/mm.h>
  10 #include <linux/swap.h>
  11 #include <linux/pagemap.h>
  12
  13 #include <asm/pgalloc.h>
  14 #include <asm/pgtable.h>
  15 #include <asm/page.h>
  16 #include <asm/cacheflush.h>
  17 #include <asm/tlbflush.h>
  18
  19 /* Remap IO memory, the same way as remap_pfn_range(), but use
  20  * the obio memory space.
  21  *
  22  * They use a pgprot that sets PAGE_IO and does not check the
  23  * mem_map table as this is independent of normal memory.
  24  */
  25 static inline void io_remap_pte_range(struct mm_struct *mm, pte_t * pte, unsigned long address, unsigned long size,
  26         unsigned long offset, pgprot_t prot, int space)
  27 {
  28         unsigned long end;
  29
  30         address &= ~PMD_MASK;
  31         end = address + size;
  32         if (end > PMD_SIZE)
  33                 end = PMD_SIZE;
  34         do {
  35                 pte_t oldpage = *pte;
  36                 pte_clear(mm, address, pte);
  37                 set_pte(pte, mk_pte_io(offset, prot, space));
  38                 address += PAGE_SIZE;
  39                 offset += PAGE_SIZE;
  40                 pte++;
  41         } while (address < end);
  42 }
  43
  44 static inline int io_remap_pmd_range(struct mm_struct *mm, pmd_t * pmd, unsigned long address, unsigned long size,
  45         unsigned long offset, pgprot_t prot, int space)
  46 {
  47         unsigned long end;
  48
  49         address &= ~PGDIR_MASK;
  50         end = address + size;
  51         if (end > PGDIR_SIZE)
  52                 end = PGDIR_SIZE;
  53         offset -= address;
  54         do {
  55                 pte_t * pte = pte_alloc_map(mm, pmd, address);
  56                 if (!pte)
  57                         return -ENOMEM;
  58                 io_remap_pte_range(mm, pte, address, end - address, address + offset, prot, space);
  59                 address = (address + PMD_SIZE) & PMD_MASK;
  60                 pmd++;
  61         } while (address < end);
  62         return 0;
  63 }
  64
  65 int io_remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
  66                         unsigned long pfn, unsigned long size, pgprot_t prot)
  67 {
  68         int error = 0;
  69         pgd_t * dir;
  70         unsigned long beg = from;
  71         unsigned long end = from + size;
  72         struct mm_struct *mm = vma->vm_mm;
  73         int space = GET_IOSPACE(pfn);
  74         unsigned long offset = GET_PFN(pfn) << PAGE_SHIFT;
  75
  76         /* See comment in mm/memory.c remap_pfn_range */
  77         vma->vm_flags |= VM_IO | VM_RESERVED | VM_UNPAGED;
  78
  79         prot = __pgprot(pg_iobits);
  80         offset -= from;
  81         dir = pgd_offset(mm, from);
  82         flush_cache_range(vma, beg, end);
  83
  84         while (from < end) {
  85                 pmd_t *pmd = pmd_alloc(mm, dir, from);
  86                 error = -ENOMEM;
  87                 if (!pmd)
  88                         break;
  89                 error = io_remap_pmd_range(mm, pmd, from, end - from, offset + from, prot, space);
  90                 if (error)
  91                         break;
  92                 from = (from + PGDIR_SIZE) & PGDIR_MASK;
  93                 dir++;
  94         }
  95
  96         flush_tlb_range(vma, beg, end);
  97         return error;
  98 }