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grub/disk/i386/pc/biosdisk.c
chaac 5915059b61 2006-07-29 Vesa Jaaskelainen <chaac@nic.fi> 
* disk/i386/pc/biosdisk.c (struct grub_biosdisk_drp): Moved to ...
        (struct grub_biosdisk_dap): Likewise.

        * include/grub/i386/pc/biosdisk.h: ... to here.  Also corrected
        linkage settings for all functions.
2006-07-29 10:11:01 +00:00

325 lines
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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2006 Free Software Foundation, Inc.
*
* GRUB is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <grub/machine/biosdisk.h>
#include <grub/machine/memory.h>
#include <grub/disk.h>
#include <grub/mm.h>
#include <grub/types.h>
#include <grub/misc.h>
#include <grub/err.h>
#include <grub/term.h>
static int
grub_biosdisk_get_drive (const char *name)
{
unsigned long drive;
if ((name[0] != 'f' && name[0] != 'h') || name[1] != 'd')
goto fail;
drive = grub_strtoul (name + 2, 0, 10);
if (grub_errno != GRUB_ERR_NONE)
goto fail;
if (name[0] == 'h')
drive += 0x80;
return (int) drive ;
fail:
grub_error (GRUB_ERR_UNKNOWN_DEVICE, "not a biosdisk");
return -1;
}
static int
grub_biosdisk_call_hook (int (*hook) (const char *name), int drive)
{
char name[10];
grub_sprintf (name, (drive & 0x80) ? "hd%d" : "fd%d", drive & (~0x80));
return hook (name);
}
static int
grub_biosdisk_iterate (int (*hook) (const char *name))
{
int drive;
int num_floppies;
/* For floppy disks, we can get the number safely. */
num_floppies = grub_biosdisk_get_num_floppies ();
for (drive = 0; drive < num_floppies; drive++)
if (grub_biosdisk_call_hook (hook, drive))
return 1;
/* For hard disks, attempt to read the MBR. */
for (drive = 0x80; drive < 0x90; drive++)
{
if (grub_biosdisk_rw_standard (0x02, drive, 0, 0, 1, 1,
GRUB_MEMORY_MACHINE_SCRATCH_SEG) != 0)
break;
if (grub_biosdisk_call_hook (hook, drive))
return 1;
}
return 0;
}
static grub_err_t
grub_biosdisk_open (const char *name, grub_disk_t disk)
{
grub_uint64_t total_sectors = 0;
int drive;
struct grub_biosdisk_data *data;
drive = grub_biosdisk_get_drive (name);
if (drive < 0)
return grub_errno;
disk->has_partitions = (drive & 0x80);
disk->id = drive;
data = (struct grub_biosdisk_data *) grub_malloc (sizeof (*data));
if (! data)
return grub_errno;
data->drive = drive;
data->flags = 0;
if (drive & 0x80)
{
/* HDD */
int version;
version = grub_biosdisk_check_int13_extensions (drive);
if (version)
{
struct grub_biosdisk_drp *drp
= (struct grub_biosdisk_drp *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
/* Clear out the DRP. */
grub_memset (drp, 0, sizeof (*drp));
drp->size = sizeof (*drp);
if (! grub_biosdisk_get_diskinfo_int13_extensions (drive, drp))
{
data->flags = GRUB_BIOSDISK_FLAG_LBA;
if (drp->total_sectors)
total_sectors = drp->total_sectors;
else
/* Some buggy BIOSes doesn't return the total sectors
correctly but returns zero. So if it is zero, compute
it by C/H/S returned by the LBA BIOS call. */
total_sectors = drp->cylinders * drp->heads * drp->sectors;
}
}
}
if (grub_biosdisk_get_diskinfo_standard (drive,
&data->cylinders,
&data->heads,
&data->sectors) != 0)
{
grub_free (data);
return grub_error (GRUB_ERR_BAD_DEVICE, "cannot get C/H/S values");
}
if (! total_sectors)
total_sectors = data->cylinders * data->heads * data->sectors;
disk->total_sectors = total_sectors;
disk->data = data;
return GRUB_ERR_NONE;
}
static void
grub_biosdisk_close (grub_disk_t disk)
{
grub_free (disk->data);
}
/* For readability. */
#define GRUB_BIOSDISK_READ 0
#define GRUB_BIOSDISK_WRITE 1
static grub_err_t
grub_biosdisk_rw (int cmd, grub_disk_t disk,
grub_disk_addr_t sector, grub_size_t size,
unsigned segment)
{
struct grub_biosdisk_data *data = disk->data;
if (data->flags & GRUB_BIOSDISK_FLAG_LBA)
{
struct grub_biosdisk_dap *dap;
dap = (struct grub_biosdisk_dap *) (GRUB_MEMORY_MACHINE_SCRATCH_ADDR
+ (data->sectors
<< GRUB_DISK_SECTOR_BITS));
dap->length = sizeof (*dap);
dap->reserved = 0;
dap->blocks = size;
dap->buffer = segment << 16; /* The format SEGMENT:ADDRESS. */
dap->block = sector;
if (grub_biosdisk_rw_int13_extensions (cmd + 0x42, data->drive, dap))
{
/* Fall back to the CHS mode. */
data->flags &= ~GRUB_BIOSDISK_FLAG_LBA;
disk->total_sectors = data->cylinders * data->heads * data->sectors;
return grub_biosdisk_rw (cmd, disk, sector, size, segment);
}
}
else
{
unsigned coff, hoff, soff;
unsigned head;
unsigned real_sector = (unsigned) sector;
/* It is impossible to reach over 2TB with the traditional
CHS access. */
if (sector > ~0UL)
return grub_error (GRUB_ERR_OUT_OF_RANGE, "out of disk");
soff = real_sector % data->sectors + 1;
head = real_sector / data->sectors;
hoff = head % data->heads;
coff = head / data->heads;
if (coff >= data->cylinders)
return grub_error (GRUB_ERR_OUT_OF_RANGE, "out of disk");
if (grub_biosdisk_rw_standard (cmd + 0x02, data->drive,
coff, hoff, soff, size, segment))
{
switch (cmd)
{
case GRUB_BIOSDISK_READ:
return grub_error (GRUB_ERR_READ_ERROR, "biosdisk read error");
case GRUB_BIOSDISK_WRITE:
return grub_error (GRUB_ERR_WRITE_ERROR, "biosdisk write error");
}
}
}
return GRUB_ERR_NONE;
}
/* Return the number of sectors which can be read safely at a time. */
static grub_size_t
get_safe_sectors (grub_disk_addr_t sector, grub_uint32_t sectors)
{
grub_size_t size;
grub_uint32_t offset;
/* OFFSET = SECTOR % SECTORS */
grub_divmod64 (sector, sectors, &offset);
size = sectors - offset;
/* Limit the max to 0x7f because of Phoenix EDD. */
if (size > 0x7f)
size = 0x7f;
return size;
}
static grub_err_t
grub_biosdisk_read (grub_disk_t disk, grub_disk_addr_t sector,
grub_size_t size, char *buf)
{
struct grub_biosdisk_data *data = disk->data;
while (size)
{
grub_size_t len;
len = get_safe_sectors (sector, data->sectors);
if (len > size)
len = size;
if (grub_biosdisk_rw (GRUB_BIOSDISK_READ, disk, sector, len,
GRUB_MEMORY_MACHINE_SCRATCH_SEG))
return grub_errno;
grub_memcpy (buf, (void *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR,
len << GRUB_DISK_SECTOR_BITS);
buf += len << GRUB_DISK_SECTOR_BITS;
sector += len;
size -= len;
}
return grub_errno;
}
static grub_err_t
grub_biosdisk_write (grub_disk_t disk, grub_disk_addr_t sector,
grub_size_t size, const char *buf)
{
struct grub_biosdisk_data *data = disk->data;
while (size)
{
grub_size_t len;
len = get_safe_sectors (sector, data->sectors);
if (len > size)
len = size;
grub_memcpy ((void *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR, buf,
len << GRUB_DISK_SECTOR_BITS);
if (grub_biosdisk_rw (GRUB_BIOSDISK_WRITE, disk, sector, len,
GRUB_MEMORY_MACHINE_SCRATCH_SEG))
return grub_errno;
buf += len << GRUB_DISK_SECTOR_BITS;
sector += len;
size -= len;
}
return grub_errno;
}
static struct grub_disk_dev grub_biosdisk_dev =
{
.name = "biosdisk",
.id = GRUB_DISK_DEVICE_BIOSDISK_ID,
.iterate = grub_biosdisk_iterate,
.open = grub_biosdisk_open,
.close = grub_biosdisk_close,
.read = grub_biosdisk_read,
.write = grub_biosdisk_write,
.next = 0
};
void
grub_biosdisk_init (void)
{
grub_disk_dev_register (&grub_biosdisk_dev);
}
void
grub_biosdisk_fini (void)
{
grub_disk_dev_unregister (&grub_biosdisk_dev);
}
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