u-boot-brain/lib_i386/realmode.c
wdenk 7a8e9bed17 * Patch by Marc Singer, 29 May 2003:
Fixed rarp boot method for IA32 and other little-endian CPUs.

* Patch by Marc Singer, 28 May 2003:
  Added port I/O commands.

* Patch by Matthew McClintock, 28 May 2003
  - cpu/mpc824x/start.S: fix relocation code when booting from RAM
  - minor patches for utx8245

* Patch by Daniel Engström, 28 May 2003:
  x86 update

* Patch by Dave Ellis, 9 May 2003 + 27 May 2003:
  add nand flash support to SXNI855T configuration
  fix/extend nand flash support:
  - fix 'nand erase' command so does not erase bad blocks
  - fix 'nand write' command so does not write to bad blocks
  - fix nand_probe() so handles no flash detected properly
  - add doc/README.nand
  - add .jffs2 and .oob options to nand read/write
  - add 'nand bad' command to list bad blocks
  - add 'clean' option to 'nand erase' to write JFFS2 clean markers
  - make NAND read/write faster

* Patch by Rune Torgersen, 23 May 2003:
  Update for MPC8266ADS board
2003-05-31 18:35:21 +00:00

97 lines
2.4 KiB
C

/*
* (C) Copyright 2002
* Daniel Engström, Omicron Ceti AB, daniel@omicron.se
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <asm/io.h>
#include <asm/ptrace.h>
#include <asm/realmode.h>
#define REALMODE_BASE ((char*)0x7c0)
#define REALMODE_MAILBOX ((char*)0xe00)
extern char realmode_enter;
int realmode_setup(void)
{
/* copy the realmode switch code */
if (i386boot_realmode_size > (REALMODE_MAILBOX-REALMODE_BASE)) {
printf("realmode switch too large (%ld bytes, max is %d)\n",
i386boot_realmode_size, (REALMODE_MAILBOX-REALMODE_BASE));
return -1;
}
memcpy(REALMODE_BASE, (void*)i386boot_realmode, i386boot_realmode_size);
asm("wbinvd\n");
return 0;
}
int enter_realmode(u16 seg, u16 off, struct pt_regs *in, struct pt_regs *out)
{
/* setup out thin bios emulation */
if (bios_setup()) {
return -1;
}
if (realmode_setup()) {
return -1;
}
in->eip = off;
in->xcs = seg;
if (3>(in->esp & 0xffff)) {
printf("Warning: entering realmode with sp < 4 will fail\n");
}
memcpy(REALMODE_MAILBOX, in, sizeof(struct pt_regs));
asm("wbinvd\n");
__asm__ volatile (
"lcall $0x20,%0\n" : : "i" (&realmode_enter) );
asm("wbinvd\n");
memcpy(out, REALMODE_MAILBOX, sizeof(struct pt_regs));
return out->eax;
}
/* This code is supposed to access a realmode interrupt
* it does currently not work for me */
int enter_realmode_int(u8 lvl, struct pt_regs *in, struct pt_regs *out)
{
/* place two instructions at 0x700 */
writeb(0xcd, 0x700); /* int $lvl */
writeb(lvl, 0x701);
writeb(0xcb, 0x702); /* lret */
asm("wbinvd\n");
enter_realmode(0x00, 0x700, in, out);
return out->eflags&1;
}