/* * (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 */ /* * Based on msbios.c from rolo 1.6: *---------------------------------------------------------------------- * (C) Copyright 2000 * Sysgo Real-Time Solutions GmbH * Klein-Winternheim, Germany *---------------------------------------------------------------------- */ /* * During it's initialization phase, before switching to protected * mode, the Linux Kernel makes a few BIOS calls. This won't work * if the board does not have a BIOS. * * This is a very minimalisic BIOS that supplies just enough * functionality to keep the Linux Kernel happy. It is NOT * a general purpose replacement for a real BIOS !! */ #define OFFS_ES 0 #define OFFS_GS 2 #define OFFS_DS 4 #define OFFS_DI 6 #define OFFS_SI 8 #define OFFS_BP 10 #define OFFS_SP 12 #define OFFS_BX 14 #define OFFS_DX 16 #define OFFS_CX 18 #define OFFS_AX 20 #define OFFS_VECTOR 22 #define OFFS_IP 24 #define OFFS_CS 26 #define OFFS_FLAGS 28 #define SEGMENT 0x40 #define STACK 0x800 /* stack at 0x40:0x800 -> 0x800 */ .section .bios, "ax" .code16 .org 0 .globl rm_int00 rm_int00: pushw $0 jmp any_interrupt16 .globl rm_int01 rm_int01: pushw $1 jmp any_interrupt16 .globl rm_int02 rm_int02: pushw $2 jmp any_interrupt16 .globl rm_int03 rm_int03: pushw $3 jmp any_interrupt16 .globl rm_int04 rm_int04: pushw $4 jmp any_interrupt16 .globl rm_int05 rm_int05: pushw $5 jmp any_interrupt16 .globl rm_int06 rm_int06: pushw $6 jmp any_interrupt16 .globl rm_int07 rm_int07: pushw $7 jmp any_interrupt16 .globl rm_int08 rm_int08: pushw $8 jmp any_interrupt16 .globl rm_int09 rm_int09: pushw $9 jmp any_interrupt16 .globl rm_int0a rm_int0a: pushw $10 jmp any_interrupt16 .globl rm_int0b rm_int0b: pushw $11 jmp any_interrupt16 .globl rm_int0c rm_int0c: pushw $12 jmp any_interrupt16 .globl rm_int0d rm_int0d: pushw $13 jmp any_interrupt16 .globl rm_int0e rm_int0e: pushw $14 jmp any_interrupt16 .globl rm_int0f rm_int0f: pushw $15 jmp any_interrupt16 .globl rm_int10 rm_int10: pushw $16 jmp any_interrupt16 .globl rm_int11 rm_int11: pushw $17 jmp any_interrupt16 .globl rm_int12 rm_int12: pushw $18 jmp any_interrupt16 .globl rm_int13 rm_int13: pushw $19 jmp any_interrupt16 .globl rm_int14 rm_int14: pushw $20 jmp any_interrupt16 .globl rm_int15 rm_int15: pushw $21 jmp any_interrupt16 .globl rm_int16 rm_int16: pushw $22 jmp any_interrupt16 .globl rm_int17 rm_int17: pushw $23 jmp any_interrupt16 .globl rm_int18 rm_int18: pushw $24 jmp any_interrupt16 .globl rm_int19 rm_int19: pushw $25 jmp any_interrupt16 .globl rm_int1a rm_int1a: pushw $26 jmp any_interrupt16 .globl rm_int1b rm_int1b: pushw $27 jmp any_interrupt16 .globl rm_int1c rm_int1c: pushw $28 jmp any_interrupt16 .globl rm_int1d rm_int1d: pushw $29 jmp any_interrupt16 .globl rm_int1e rm_int1e: pushw $30 jmp any_interrupt16 .globl rm_int1f rm_int1f: pushw $31 jmp any_interrupt16 .globl rm_def_int rm_def_int: iret /* * All interrupt jumptable entries jump to here * after pushing the interrupt vector number onto the * stack. */ any_interrupt16: pusha /* save general registers */ pushw %ds /* save some segments */ pushw %gs pushw %es pushw %ss /* save callers stack segment .. */ popw %gs /* ... in gs */ movw $SEGMENT,%ax /* setup my segments */ movw %ax,%ds movw %ax,%es movw %ax,%ss movw %sp,%bp movw $STACK,%sp /* setup BIOS stackpointer */ gs movw OFFS_VECTOR(%bp), %ax cmpw $0x10, %ax je Lint_10h cmpw $0x11, %ax je Lint_11h cmpw $0x13, %ax je Lint_13h cmpw $0x15, %ax je Lint_15h cmpw $0x16, %ax je Lint_16h movw $0xffff, %ax jmp Lout Lint_10h: /* VGA BIOS services */ call bios_10h jmp Lout Lint_11h: call bios_11h jmp Lout Lint_13h: /* BIOS disk services */ call bios_13h jmp Lout Lint_15h: /* Misc. BIOS services */ call bios_15h jmp Lout Lint_16h: /* keyboard services */ call bios_16h jmp Lout Lout: cmpw $0, %ax je Lhandeled /* Insert code for unhandeled INTs here. * * ROLO prints a message to the console * (we could do that but then we're in 16bit mode * so we'll have to get back into 32bit mode * to use the console I/O routines (if we do this * we shuls make int 0x10 and int 0x16 work as well)) */ Lhandeled: pushw %gs /* restore callers stack segment */ popw %ss movw %bp,%sp /* restore stackpointer */ popw %es /* restore segment selectors */ popw %gs popw %ds popa /* restore GP registers */ addw $2,%sp /* dump vector number */ iret /* return from interrupt */ /* ************************************************************ * BIOS interrupt 10h -- VGA services ************************************************************ */ bios_10h: gs movw OFFS_AX(%bp), %ax shrw $8, %ax cmpw $0x3, %ax je Lcur_pos cmpw $0xf, %ax je Lvid_state cmpw $0x12, %ax je Lvid_cfg movw $0xffff, %ax ret Lcur_pos: /* Read Cursor Position and Size */ gs movw $0, OFFS_CX(%bp) gs movw $0, OFFS_DX(%bp) xorw %ax, %ax ret Lvid_state: /* Get Video State */ gs movw $(80 << 8|0x03), OFFS_AX(%bp) /* 80 columns, 80x25, 16 colors */ gs movw $0, OFFS_BX(%bp) xorw %ax, %ax ret Lvid_cfg: /* Video Subsystem Configuration (EGA/VGA) */ gs movw $0x10, OFFS_BX(%bp) /* indicate CGA/MDA/HGA */ xorw %ax, %ax ret /* ************************************************************ * BIOS interrupt 11h -- Equipment determination ************************************************************ */ bios_11h: movw bios_equipment, %ax gs movw %ax, OFFS_AX(%bp) xorw %ax, %ax ret /* ************************************************************ * BIOS interrupt 13h -- Disk services ************************************************************ */ bios_13h: gs movw OFFS_AX(%bp), %ax shrw $8, %ax cmpw $0x15, %ax je Lfunc_15h movw $0xffff, %ax ret Lfunc_15h: gs movw OFFS_AX(%bp), %ax andw $0xff, %ax /* return AH=0->drive not present */ gs movw %ax, OFFS_AX(%bp) xorw %ax, %ax ret /* *********************************************************** * BIOS interrupt 15h -- Miscellaneous services *********************************************************** */ bios_15h: gs movw OFFS_AX(%bp), %ax shrw $8, %ax cmpw $0xc0, %ax je Lfunc_c0h cmpw $0xe8, %ax je Lfunc_e8h cmpw $0x88, %ax je Lfunc_88h movw $0xffff, %ax ret Lfunc_c0h: /* Return System Configuration Parameters (PS2 only) */ gs movw OFFS_FLAGS(%bp), %ax orw $1, %ax /* return carry -- function not supported */ gs movw %ax, OFFS_FLAGS(%bp) xorw %ax, %ax ret Lfunc_e8h: gs movw OFFS_AX(%bp), %ax andw $0xff, %ax cmpw $1, %ax je Lfunc_e801h gs movw OFFS_FLAGS(%bp), %ax orw $1, %ax /* return carry -- function not supported */ gs movw %ax, OFFS_FLAGS(%bp) xorw %ax, %ax ret Lfunc_e801h: /* Get memory size for >64M Configurations */ movw $ram_in_64kb_chunks, %ax cmpw $256, %ax ja Lmore_than_16mb shlw $6, %ax /* multiply by 64 */ gs movw %ax, OFFS_AX(%bp) /* return memory size in 1kb chunks in AX and CX */ gs movw %ax, OFFS_CX(%bp) xorw %ax, %ax gs movw %ax, OFFS_BX(%bp) /* set BX and DX to 0*/ gs movw %ax, OFFS_DX(%bp) gs movw OFFS_FLAGS(%bp), %ax andw $0xfffe, %ax /* clear carry -- function succeeded */ gs movw %ax, OFFS_FLAGS(%bp) xorw %ax, %ax ret Lmore_than_16mb: subw $0x100, %ax /* subtract 16MB */ gs movw $0x3c00, OFFS_AX(%bp) /* return 0x3c00 (16MB-384k) in AX and CX */ gs movw $0x3c00, OFFS_CX(%bp) gs movw %ax, OFFS_BX(%bp) /* set BX and DX to number of 64kb chunks - 256 */ gs movw %ax, OFFS_DX(%bp) gs movw OFFS_FLAGS(%bp), %ax andw $0xfffe, %ax /* clear carry -- function succeeded */ gs movw %ax, OFFS_FLAGS(%bp) xorw %ax, %ax ret Lfunc_88h: movw ram_in_64kb_chunks, %ax subw $16, %ax shlw $6, %ax gs movw %ax, OFFS_AX(%bp) /* return number of kilobytes in ax */ gs movw OFFS_FLAGS(%bp), %ax andw $0xfffe, %ax /* clear carry -- function succeeded */ gs movw %ax, OFFS_FLAGS(%bp) xorw %ax, %ax ret /* ************************************************************ * BIOS interrupt 16h -- keyboard services ************************************************************ */ bios_16h: gs movw OFFS_AX(%bp), %ax shrw $8, %ax cmpw $0x03, %ax je Lfunc_03h movw $0xffff, %ax ret Lfunc_03h: xorw %ax, %ax /* do nothing -- function not supported */ ret .globl ram_in_64kb_chunks ram_in_64kb_chunks: .word 0 .globl bios_equipment bios_equipment: .word 0