diff options
Diffstat (limited to 'sys/arch/i386/stand/wdbootblk.S')
| -rw-r--r-- | sys/arch/i386/stand/wdbootblk.S | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/sys/arch/i386/stand/wdbootblk.S b/sys/arch/i386/stand/wdbootblk.S new file mode 100644 index 00000000000..73cf95643b0 --- /dev/null +++ b/sys/arch/i386/stand/wdbootblk.S @@ -0,0 +1,235 @@ +/* $NetBSD: wdbootblk.c,v 1.3 1994/10/27 04:22:02 cgd Exp $ */ + +/*- + * Copyright (c) 1990 The Regents of the University of California. + * All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * William Jolitz. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * @(#)wdbootblk.c 7.1 (Berkeley) 4/28/91 + */ + +/* + * wdbootblk.s: + * Written 7/6/90 by William F. Jolitz + * Initial block boot for AT/386 with typical Western Digital + * WD 1002-WA2 (or upwards compatable). Works either as + * first and sole partition bootstrap, or as loaded by a + * earlier BIOS boot when on an inner partition of the disk. + * + * Goal is to read in sucessive 7.5Kbytes of bootstrap to + * execute. + * + * No attempt is made to handle disk errors. + */ + +#include <dev/isa/isareg.h> +#include <dev/isa/wdreg.h> + +#define NOP inb $0x84,%al +#define BIOSRELOC 0x7c00 +#define start RELOC+0x400 + + /* step 0 force descriptors to bottom of address space */ + + cli + .byte 0xb8,0x30,0x00 /* mov $0x30,%ax */ + mov %ax, %ss + .byte 0xbc,0x00,0x01 /* mov $0x100,%sp */ + + xorl %eax,%eax + movl %ax,%ds + movl %ax,%es + + /* obtain BIOS parameters for hard disk XXX */ + movb $0x9f,%ah /* write to 0x9ff00 XXX */ + movb $0xf0,%al + mov %ax,%es + xor %edi,%edi + + .byte 0xf, 0xb4, 0x36 ; .word 0x41*4 /* lfs 0x41*4, %si */ + xorb %ch,%ch + movb $0x10,%cl + fs + rep + movsb + + .byte 0xf, 0xb4, 0x36 ; .word 0x46*4 /* lfs 0x46*4, %si */ + xorb %ch,%ch + movb $0x10,%cl + fs + rep + movsb + + xorl %eax,%eax + movl %ax,%es + + /* step 1 load new descriptor table */ + + .byte 0x3E,0x0F,1,0x16 + .word BIOSRELOC+0x6e #GDTptr + # word aword cs lgdt GDTptr + + /* step 2 turn on protected mode */ + + smsw %ax + orb $1,%al + lmsw %ax + jmp 1f + nop + + /* step 3 reload segment descriptors */ + +1: + xorl %eax,%eax + movb $0x10,%al + movl %ax,%ds + movl %ax,%es + movl %ax,%ss + word + ljmp $0x8,$ BIOSRELOC+0x74 /* would be nice if .-RELOC+0x7c00 worked */ + + /* Global Descriptor Table contains three descriptors: + * 0x00: Null: not used + * 0x08: Code: code segment starts at 0 and extents for 4 gigabytes + * 0x10: Data: data segment starts at 0 and extends for 4 gigabytes + * (overlays code) + */ +GDT: +NullDesc: .word 0,0,0,0 # null descriptor - not used +CodeDesc: .word 0xFFFF # limit at maximum: (bits 15:0) + .byte 0,0,0 # base at 0: (bits 23:0) + .byte 0x9f # present/priv level 0/code/conforming/readable + .byte 0xcf # page granular/default 32-bit/limit(bits 19:16) + .byte 0 # base at 0: (bits 31:24) +DataDesc: .word 0xFFFF # limit at maximum: (bits 15:0) + .byte 0,0,0 # base at 0: (bits 23:0) + .byte 0x93 # present/priv level 0/data/expand-up/writeable + .byte 0xcf # page granular/default 32-bit/limit(bits 19:16) + .byte 0 # base at 0: (bits 31:24) + +/* Global Descriptor Table pointer + * contains 6-byte pointer information for LGDT + */ +GDTptr: .word 0x17 # limit to three 8 byte selectors(null,code,data) + .long BIOSRELOC+0x56 # GDT -- arrgh, gas again! + + /* step 4 relocate to final bootstrap address. */ +reloc: + movl $ BIOSRELOC,%esi + movl $ RELOC,%edi + movl $512,%ecx + rep + movsb + movl $0xa0000, %esp + pushl $dodisk + ret + + /* step 5 load remaining 15 sectors off disk */ +dodisk: + movl $ IO_WD1+wd_seccnt,%edx + movb $ 15,%al + outb %al,%dx + NOP + movl $ IO_WD1+wd_sector,%edx + movb $ 2,%al + outb %al,%dx + NOP + #outb(wdc+wd_cyl_lo, (cyloffset & 0xff)); + #outb(wdc+wd_cyl_hi, (cyloffset >> 8)); + #outb(wdc+wd_sdh, WDSD_IBM | (unit << 4)); + + movl $ IO_WD1+wd_command,%edx + movb $ WDCC_READ,%al + outb %al,%dx + NOP + cld + + /* check to make sure controller is not busy and we have data ready */ +readblk: + movl $ IO_WD1+wd_status,%edx + NOP + inb %dx,%al + testb $ WDCS_BSY,%al + jnz readblk + testb $ WDCS_DRQ,%al + jz readblk + + /* read a block into final position in memory */ + + movl $ IO_WD1+wd_data,%edx + movl $ 256,%ecx + .byte 0x66,0xf2,0x6d # rep insw + NOP + + /* need more blocks to be read in? */ + + cmpl $ RELOC+16*512-1,%edi + jl readblk + + /* for clever bootstrap, dig out boot unit and cylinder */ + + movl $ IO_WD1+wd_cyl_lo,%edx + inb %dx,%al + xorl %ecx,%ecx + movb %al,%cl + incl %edx + NOP + inb %dx,%al /* cyl_hi */ + movb %al,%ch + pushl %ecx /* cyloffset */ + + incl %edx + xorl %eax,%eax + NOP + inb %dx,%al /* sdh */ + andb $0x10,%al /* isolate unit # bit */ + shrb $4,%al + pushl %eax /* unit */ + + /* wd controller is major device 0 */ + xorl %eax,%eax + pushl %eax /* bootdev */ + + /* sorry, no flags at this point! */ + + movl $ start, %eax + call %eax /* main (dev, unit, offset) */ + +ebootblkcode: + + /* remaining space usable for a disk label */ + + .org 0x1fe + .word 0xaa55 /* signature -- used by BIOS ROM */ + +ebootblk: /* MUST BE EXACTLY 0x200 BIG FOR SURE */ |