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Diffstat (limited to 'qemu/roms/ipxe/src/arch/i386/transitions/liba20.S')
| -rw-r--r-- | qemu/roms/ipxe/src/arch/i386/transitions/liba20.S | 313 |
1 files changed, 0 insertions, 313 deletions
diff --git a/qemu/roms/ipxe/src/arch/i386/transitions/liba20.S b/qemu/roms/ipxe/src/arch/i386/transitions/liba20.S deleted file mode 100644 index 6c1e1f62f..000000000 --- a/qemu/roms/ipxe/src/arch/i386/transitions/liba20.S +++ /dev/null @@ -1,313 +0,0 @@ -/* - * Copyright (C) 2010 Michael Brown <mbrown@fensystems.co.uk>. - * - * 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 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., 51 Franklin Street, Fifth Floor, Boston, MA - * 02110-1301, USA. - * - * You can also choose to distribute this program under the terms of - * the Unmodified Binary Distribution Licence (as given in the file - * COPYING.UBDL), provided that you have satisfied its requirements. - * - */ - -FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ) - - .arch i386 - -/**************************************************************************** - * test_a20_short, test_a20_long - * - * Check to see if A20 line is enabled - * - * Parameters: - * none - * Returns: - * CF set if A20 line is not enabled - * Corrupts: - * none - **************************************************************************** - */ -#define TEST_A20_SHORT_MAX_RETRIES 0x20 -#define TEST_A20_LONG_MAX_RETRIES 0x200000 - .section ".text16.early", "awx", @progbits - .code16 -test_a20_short: - pushl %ecx - movl $TEST_A20_SHORT_MAX_RETRIES, %ecx - jmp 1f - .size test_a20_short, . - test_a20_short -test_a20_long: - pushl %ecx - movl $TEST_A20_LONG_MAX_RETRIES, %ecx -1: pushw %ax - pushw %ds - pushw %es - - /* Set up segment registers for access across the 1MB boundary */ - xorw %ax, %ax - movw %ax, %ds - decw %ax - movw %ax, %es - -2: /* Modify and check test pattern; succeed if we see a difference */ - pushfw - cli - xchgw %ds:0, %cx - movw %es:0x10, %ax - xchgw %ds:0, %cx - popfw - cmpw %ax, %cx - clc - jnz 99f - - /* Delay and retry */ - outb %al, $0x80 - addr32 loop 2b - stc - -99: /* Restore registers and return */ - popw %es - popw %ds - popw %ax - popl %ecx - ret - .size test_a20_long, . - test_a20_long - -/**************************************************************************** - * enable_a20_bios - * - * Try enabling A20 line via BIOS - * - * Parameters: - * none - * Returns: - * CF set if A20 line is not enabled - * Corrupts: - * none - **************************************************************************** - */ - .section ".text16.early", "awx", @progbits - .code16 -enable_a20_bios: - - /* Preserve registers. Be very paranoid, since some BIOSes - * are reported to clobber %ebx - */ - pushal - - /* Attempt INT 15,2401 */ - movw $0x2401, %ax - int $0x15 - jc 99f - - /* Check that success was really successful */ - call test_a20_short - -99: /* Restore registers and return */ - popal - ret - .size enable_a20_bios, . - enable_a20_bios - -/**************************************************************************** - * enable_a20_kbc - * - * Try enabling A20 line via keyboard controller - * - * Parameters: - * none - * Returns: - * CF set if A20 line is not enabled - * Corrupts: - * none - **************************************************************************** - */ -#define KC_RDWR 0x60 -#define KC_RDWR_SET_A20 0xdf -#define KC_CMD 0x64 -#define KC_CMD_WOUT 0xd1 -#define KC_CMD_NULL 0xff -#define KC_STATUS 0x64 -#define KC_STATUS_OBUF_FULL 0x01 -#define KC_STATUS_IBUF_FULL 0x02 -#define KC_MAX_RETRIES 100000 - .section ".text16.early", "awx", @progbits - .code16 -enable_a20_kbc: - /* Preserve registers */ - pushw %ax - - /* Try keyboard controller */ - call empty_kbc - movb $KC_CMD_WOUT, %al - outb %al, $KC_CMD - call empty_kbc - movb $KC_RDWR_SET_A20, %al - outb %al, $KC_RDWR - call empty_kbc - movb $KC_CMD_NULL, %al - outb %al, $KC_CMD - call empty_kbc - - /* Check to see if it worked */ - call test_a20_long - - /* Restore registers and return */ - popw %ax - ret - .size enable_a20_kbc, . - enable_a20_kbc - - .section ".text16.early", "awx", @progbits - .code16 -empty_kbc: - /* Preserve registers */ - pushl %ecx - pushw %ax - - /* Wait for KBC to become empty */ - movl $KC_MAX_RETRIES, %ecx -1: outb %al, $0x80 - inb $KC_STATUS, %al - testb $( KC_STATUS_OBUF_FULL | KC_STATUS_IBUF_FULL ), %al - jz 99f - testb $KC_STATUS_OBUF_FULL, %al - jz 2f - outb %al, $0x80 - inb $KC_RDWR, %al -2: addr32 loop 1b - -99: /* Restore registers and return */ - popw %ax - popl %ecx - ret - .size empty_kbc, . - empty_kbc - -/**************************************************************************** - * enable_a20_fast - * - * Try enabling A20 line via "Fast Gate A20" - * - * Parameters: - * none - * Returns: - * CF set if A20 line is not enabled - * Corrupts: - * none - **************************************************************************** - */ -#define SCP_A 0x92 - .section ".text16.early", "awx", @progbits - .code16 -enable_a20_fast: - /* Preserve registers */ - pushw %ax - - /* Try "Fast Gate A20" */ - inb $SCP_A, %al - orb $0x02, %al - andb $~0x01, %al - outb %al, $SCP_A - - /* Check to see if it worked */ - call test_a20_long - - /* Restore registers and return */ - popw %ax - ret - .size enable_a20_fast, . - enable_a20_fast - -/**************************************************************************** - * enable_a20 - * - * Try enabling A20 line via any available method - * - * Parameters: - * none - * Returns: - * CF set if A20 line is not enabled - * Corrupts: - * none - **************************************************************************** - */ -#define ENABLE_A20_RETRIES 255 - .section ".text16.early", "awx", @progbits - .code16 - .globl enable_a20 -enable_a20: - /* Preserve registers */ - pushl %ecx - pushw %ax - - /* Check to see if A20 is already enabled */ - call test_a20_short - jnc 99f - - /* Use known working method, if we have one */ - movw %cs:enable_a20_method, %ax - testw %ax, %ax - jz 1f - call *%ax - jmp 99f -1: - /* Try all methods in turn until one works */ - movl $ENABLE_A20_RETRIES, %ecx -2: movw $enable_a20_bios, %ax - movw %ax, %cs:enable_a20_method - call *%ax - jnc 99f - movw $enable_a20_kbc, %ax - movw %ax, %cs:enable_a20_method - call *%ax - jnc 99f - movw $enable_a20_fast, %ax - movw %ax, %cs:enable_a20_method - call *%ax - jnc 99f - addr32 loop 2b - /* Failure; exit with carry set */ - movw $0, %cs:enable_a20_method - stc - -99: /* Restore registers and return */ - popw %ax - popl %ecx - ret - - .section ".text16.early.data", "aw", @progbits - .align 2 -enable_a20_method: - .word 0 - .size enable_a20_method, . - enable_a20_method - -/**************************************************************************** - * access_highmem (real mode far call) - * - * Open up access to high memory with A20 enabled - * - * Parameters: - * none - * Returns: - * CF set if high memory could not be accessed - * Corrupts: - * none - **************************************************************************** - */ - .section ".text16.early", "awx", @progbits - .code16 - .globl access_highmem -access_highmem: - /* Enable A20 line */ - call enable_a20 - lret - .size access_highmem, . - access_highmem |