commands/i386/pc/acpi.c

   1 /* acpi.c - get acpi tables. */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2009  Free Software Foundation, Inc.
   5  *
   6  *  GRUB is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  GRUB is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <grub/acpi.h>
  21 #include <grub/misc.h>
  22
  23 struct grub_acpi_rsdp_v10 *
  24 grub_machine_acpi_get_rsdpv1 (void)
  25 {
  26   int ebda_len;
  27   grub_uint8_t *ebda, *ptr;
  28
  29   grub_dprintf ("acpi", "Looking for RSDP. Scanning EBDA\n");
  30   ebda = (grub_uint8_t *) ((* ((grub_uint16_t *) 0x40e)) << 4);
  31   ebda_len = * (grub_uint16_t *) ebda;
  32   if (! ebda_len)
  33     return 0;
  34   for (ptr = ebda; ptr < ebda + 0x400; ptr += 16)
  35     if (grub_memcmp (ptr, "RSD PTR ", 8) == 0
  36         && grub_byte_checksum (ptr, sizeof (struct grub_acpi_rsdp_v10)) == 0
  37         && ((struct grub_acpi_rsdp_v10 *) ptr)->revision == 0)
  38       return (struct grub_acpi_rsdp_v10 *) ptr;
  39
  40   grub_dprintf ("acpi", "Looking for RSDP. Scanning BIOS\n");
  41   for (ptr = (grub_uint8_t *) 0xe0000; ptr < (grub_uint8_t *) 0x100000;
  42        ptr += 16)
  43     if (grub_memcmp (ptr, "RSD PTR ", 8) == 0
  44         && grub_byte_checksum (ptr, sizeof (struct grub_acpi_rsdp_v10)) == 0
  45         && ((struct grub_acpi_rsdp_v10 *) ptr)->revision == 0)
  46       return (struct grub_acpi_rsdp_v10 *) ptr;
  47   return 0;
  48 }
  49
  50 struct grub_acpi_rsdp_v20 *
  51 grub_machine_acpi_get_rsdpv2 (void)
  52 {
  53   int ebda_len;
  54   grub_uint8_t *ebda, *ptr;
  55
  56   grub_dprintf ("acpi", "Looking for RSDP. Scanning EBDA\n");
  57   ebda = (grub_uint8_t *) ((* ((grub_uint16_t *) 0x40e)) << 4);
  58   ebda_len = * (grub_uint16_t *) ebda;
  59   if (! ebda_len)
  60     return 0;
  61   for (ptr = ebda; ptr < ebda + 0x400; ptr += 16)
  62     if (grub_memcmp (ptr, "RSD PTR ", 8) == 0
  63         && grub_byte_checksum (ptr, sizeof (struct grub_acpi_rsdp_v10)) == 0
  64         && ((struct grub_acpi_rsdp_v10 *) ptr)->revision != 0
  65         && ((struct grub_acpi_rsdp_v20 *) ptr)->length < 1024
  66         && grub_byte_checksum (ptr, ((struct grub_acpi_rsdp_v20 *) ptr)->length)
  67         == 0)
  68       return (struct grub_acpi_rsdp_v20 *) ptr;
  69
  70   grub_dprintf ("acpi", "Looking for RSDP. Scanning BIOS\n");
  71   for (ptr = (grub_uint8_t *) 0xe0000; ptr < (grub_uint8_t *) 0x100000;
  72        ptr += 16)
  73     if (grub_memcmp (ptr, "RSD PTR ", 8) == 0
  74         && grub_byte_checksum (ptr, sizeof (struct grub_acpi_rsdp_v10)) == 0
  75         && ((struct grub_acpi_rsdp_v10 *) ptr)->revision != 0
  76         && ((struct grub_acpi_rsdp_v20 *) ptr)->length < 1024
  77         && grub_byte_checksum (ptr, ((struct grub_acpi_rsdp_v20 *) ptr)->length)
  78         == 0)
  79       return (struct grub_acpi_rsdp_v20 *) ptr;
  80   return 0;
  81 }