i386/linux/linux-2.3.21/arch/sparc/mm/generic.c

   1 /* $Id: generic.c,v 1.6 1998/10/27 23:28:00 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
  12 #include <asm/pgtable.h>
  13 #include <asm/page.h>
  14
  15
  16 /* Allocate a block of RAM which is aligned to its size.
  17  * This procedure can be used until the call to mem_init().
  18  */
  19 void *sparc_init_alloc(unsigned long *kbrk, unsigned long size)
  20 {
  21         unsigned long mask = size - 1;
  22         unsigned long ret;
  23
  24         if(!size)
  25                 return 0x0;
  26         if(size & mask) {
  27                 prom_printf("panic: sparc_init_alloc botch\n");
  28                 prom_halt();
  29         }
  30         ret = (*kbrk + mask) & ~mask;
  31         *kbrk = ret + size;
  32         memset((void*) ret, 0, size);
  33         return (void*) ret;
  34 }
  35
  36 static inline void forget_pte(pte_t page)
  37 {
  38         if (pte_none(page))
  39                 return;
  40         if (pte_present(page)) {
  41                 unsigned long addr = pte_page(page);
  42                 if (MAP_NR(addr) >= max_mapnr || PageReserved(mem_map+MAP_NR(addr)))
  43                         return;
  44                 /*
  45                  * free_page() used to be able to clear swap cache
  46                  * entries.  We may now have to do it manually.
  47                  */
  48                 free_page_and_swap_cache(addr);
  49                 return;
  50         }
  51         swap_free(pte_val(page));
  52 }
  53
  54 /* Remap IO memory, the same way as remap_page_range(), but use
  55  * the obio memory space.
  56  *
  57  * They use a pgprot that sets PAGE_IO and does not check the
  58  * mem_map table as this is independent of normal memory.
  59  */
  60 static inline void io_remap_pte_range(pte_t * pte, unsigned long address, unsigned long size,
  61         unsigned long offset, pgprot_t prot, int space)
  62 {
  63         unsigned long end;
  64
  65         address &= ~PMD_MASK;
  66         end = address + size;
  67         if (end > PMD_SIZE)
  68                 end = PMD_SIZE;
  69         do {
  70                 pte_t oldpage = *pte;
  71                 pte_clear(pte);
  72                 set_pte(pte, mk_pte_io(offset, prot, space));
  73                 forget_pte(oldpage);
  74                 address += PAGE_SIZE;
  75                 offset += PAGE_SIZE;
  76                 pte++;
  77         } while (address < end);
  78 }
  79
  80 static inline int io_remap_pmd_range(pmd_t * pmd, unsigned long address, unsigned long size,
  81         unsigned long offset, pgprot_t prot, int space)
  82 {
  83         unsigned long end;
  84
  85         address &= ~PGDIR_MASK;
  86         end = address + size;
  87         if (end > PGDIR_SIZE)
  88                 end = PGDIR_SIZE;
  89         offset -= address;
  90         do {
  91                 pte_t * pte = pte_alloc(pmd, address);
  92                 if (!pte)
  93                         return -ENOMEM;
  94                 io_remap_pte_range(pte, address, end - address, address + offset, prot, space);
  95                 address = (address + PMD_SIZE) & PMD_MASK;
  96                 pmd++;
  97         } while (address < end);
  98         return 0;
  99 }
 100
 101 int io_remap_page_range(unsigned long from, unsigned long offset, unsigned long size, pgprot_t prot, int space)
 102 {
 103         int error = 0;
 104         pgd_t * dir;
 105         unsigned long beg = from;
 106         unsigned long end = from + size;
 107
 108         prot = __pgprot(pg_iobits);
 109         offset -= from;
 110         dir = pgd_offset(current->mm, from);
 111         flush_cache_range(current->mm, beg, end);
 112         while (from < end) {
 113                 pmd_t *pmd = pmd_alloc(dir, from);
 114                 error = -ENOMEM;
 115                 if (!pmd)
 116                         break;
 117                 error = io_remap_pmd_range(pmd, from, end - from, offset + from, prot, space);
 118                 if (error)
 119                         break;
 120                 from = (from + PGDIR_SIZE) & PGDIR_MASK;
 121                 dir++;
 122         }
 123         flush_tlb_range(current->mm, beg, end);
 124         return error;
 125 }