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