arch/mips/baget/baget.c

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