arch/mips/baget/baget.c

   1 /* $Id$
   2  *
   3  * baget.c: Baget low level stuff
   4  *
   5  * Copyright (C) 1998 Gleb Raiko & Vladimir Roganov
   6  *
   7  */
   8 #include <stdarg.h>
   9
  10 #include <linux/kernel.h>
  11 #include <linux/mm.h>
  12 #include <asm/system.h>
  13 #include <asm/bootinfo.h>
  14 #include <asm/mipsregs.h>
  15 #include <asm/pgtable.h>
  16
  17 #include <asm/baget/baget.h>
  18
  19 /*
  20  * Following values are set by BALO into RAM disk buffer parameters
  21  */
  22 unsigned long balo_ramdisk_base = 0xBA;  /* Signature for BALO ! */
  23 unsigned long balo_ramdisk_size = 0;
  24
  25
  26 /*
  27  *  Following code is based on routines from 'mm/vmalloc.c'
  28  *  Additional parameters  ioaddr  is needed to iterate across real I/O address.
  29  */
  30 static inline int alloc_area_pte(pte_t * pte, unsigned long address,
  31                                  unsigned long size, unsigned long ioaddr)
  32 {
  33         unsigned long end;
  34
  35         address &= ~PMD_MASK;
  36         end = address + size;
  37         if (end > PMD_SIZE)
  38                 end = PMD_SIZE;
  39         while (address < end) {
  40                 unsigned long page;
  41                 if (!pte_none(*pte))
  42                         printk("kseg2_alloc_io: page already exists\n");
  43                 /*
  44                  *  For MIPS looks pretty to have transparent mapping
  45                  *  for KSEG2 areas  -- user can't access one, and no
  46                  *  problems with  virtual <--> physical  translation.
  47                  */
  48                 page = ioaddr & PAGE_MASK;
  49
  50                 set_pte(pte, __pte(page | pgprot_val(PAGE_USERIO) |
  51                                   _PAGE_GLOBAL | __READABLE | __WRITEABLE));
  52                 address += PAGE_SIZE;
  53                 ioaddr  += PAGE_SIZE;
  54                 pte++;
  55         }
  56         return 0;
  57 }
  58
  59 static inline int alloc_area_pmd(pmd_t * pmd, unsigned long address,
  60                                  unsigned long size, unsigned long ioaddr)
  61 {
  62         unsigned long end;
  63
  64         address &= ~PGDIR_MASK;
  65         end = address + size;
  66         if (end > PGDIR_SIZE)
  67                 end = PGDIR_SIZE;
  68         while (address < end) {
  69                 pte_t * pte = pte_alloc_kernel(pmd, address);
  70                 if (!pte)
  71                         return -ENOMEM;
  72                 if (alloc_area_pte(pte, address, end - address, ioaddr))
  73                         return -ENOMEM;
  74                 address = (address + PMD_SIZE) & PMD_MASK;
  75                 ioaddr  += PMD_SIZE;
  76                 pmd++;
  77         }
  78         return 0;
  79 }
  80
  81 int kseg2_alloc_io (unsigned long address, unsigned long size)
  82 {
  83         pgd_t * dir;
  84         unsigned long end = address + size;
  85
  86         dir = pgd_offset_k(address);
  87         flush_cache_all();
  88         while (address < end) {
  89                 pmd_t *pmd;
  90                 pgd_t olddir = *dir;
  91
  92                 pmd = pmd_alloc_kernel(dir, address);
  93                 if (!pmd)
  94                         return -ENOMEM;
  95                 if (alloc_area_pmd(pmd, address, end - address, address))
  96                         return -ENOMEM;
  97                 if (pgd_val(olddir) != pgd_val(*dir))
  98                         set_pgdir(address, *dir);
  99                 address = (address + PGDIR_SIZE) & PGDIR_MASK;
 100                 dir++;
 101         }
 102         flush_tlb_all();
 103         return 0;
 104 }