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1.1 root 1: /*-
2: * Copyright (c) 1990 The Regents of the University of California.
3: * All rights reserved.
4: *
5: * This code is derived from software contributed to Berkeley by
6: * William Jolitz.
7: *
8: * Redistribution and use in source and binary forms, with or without
9: * modification, are permitted provided that the following conditions
10: * are met:
11: * 1. Redistributions of source code must retain the above copyright
12: * notice, this list of conditions and the following disclaimer.
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in the
15: * documentation and/or other materials provided with the distribution.
16: * 3. All advertising materials mentioning features or use of this software
17: * must display the following acknowledgement:
18: * This product includes software developed by the University of
19: * California, Berkeley and its contributors.
20: * 4. Neither the name of the University nor the names of its contributors
21: * may be used to endorse or promote products derived from this software
22: * without specific prior written permission.
23: *
24: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34: * SUCH DAMAGE.
35: *
1.1.1.5 ! root 36: * from: @(#)fdbootblk.c 7.2 (Berkeley) 5/4/91
! 37: * fdbootblk.c,v 1.4 1993/05/22 08:02:15 cgd Exp
1.1 root 38: */
39:
40: /*
41: * fdbootblk.s:
42: * Written 10/6/90 by William F. Jolitz
43: * Initial block boot for AT/386 with typical stupid NEC controller
44: *
45: * Goal is to read in sucessive 7.5Kbytes of bootstrap to
46: * execute.
47: *
48: * No attempt is made to handle disk errors.
1.1.1.4 root 49: *
50: * PATCHES MAGIC LEVEL PATCH THAT GOT US HERE
51: * -------------------- ----- ----------------------
52: * CURRENT PATCH LEVEL: 1 00073
53: * -------------------- ----- ----------------------
54: *
55: * 22 Jan 93 Frank Maclachlan Fixed NOP's to read correct register
56: *
1.1 root 57: */
58: /*#include "/sys/i386/isa/isa.h"
59: #include "/sys/i386/isa/fdreg.h"*/
1.1.1.3 root 60: #define NOP inb $0x84,%al
1.1 root 61: #define BIOSRELOC 0x7c00
1.1.1.3 root 62: #define start RELOC+0x400
1.1 root 63:
1.1.1.3 root 64: /* mumbo-jumbo to pacify DOS, in the hope of getting diskcopy to work */
65: jmp 1f
1.1.1.5 ! root 66: .asciz "NetBSD "
1.1.1.3 root 67: .byte 1 # sectors per allocation
68: .word 15 # additional sectors for bootstrap
69: .word 0 # number of DOS fat sectors
70: .word 0 # number of DOS rootdir entries
71: .byte 0xf0 # media descriptor
72: .word 0 # number of sectors per a DOS fat entry
73: .word 18 # number of sectors per track
74: .word 2 # number of heads
75: .long 0 # number of hidden sectors
76: .long 2880-18 # logical sectors per volume
77: .byte 0 # physical drive
78: .byte 0x29 # ?
79: .long 137 # binary id
80: .ascii "Release 0.1" # volume label
81: .space 5
82: 1:
1.1 root 83: /* step 0 force descriptors to bottom of address space */
1.1.1.3 root 84:
85: cli
86: .byte 0xb8,0x30,0x00 /* mov $0x30,%ax */
87: mov %ax, %ss
88: .byte 0xbc,0x00,0x01 /* mov $0x100,%sp */
1.1 root 89:
90: xorl %eax,%eax
91: movl %ax,%ds
92: movl %ax,%es
93:
1.1.1.3 root 94: /* obtain BIOS parameters for hard disk XXX */
95: movb $0x9f,%ah /* write to 0x9ff00 XXX */
96: movb $0xf0,%al
97: mov %ax,%es
98: xor %edi,%edi
99:
100: .byte 0xf, 0xb4, 0x36 ; .word 0x41*4 /* lfs 0x41*4, %si */
101: xorb %ch,%ch
102: movb $0x10,%cl
103: fs
104: rep
105: movsb
106:
107: .byte 0xf, 0xb4, 0x36 ; .word 0x46*4 /* lfs 0x46*4, %si */
108: xorb %ch,%ch
109: movb $0x10,%cl
110: fs
111: rep
112: movsb
113:
114: xorl %eax,%eax
115: movl %ax,%es
116:
1.1 root 117: /* step 1 load new descriptor table */
118:
1.1.1.3 root 119: .byte 0x2E,0x0F,1,0x16 /* word aword cs lgdt GDTptr */
120: .word BIOSRELOC+0xa4 #GDTptr
1.1 root 121:
122: /* step 2 turn on protected mode */
123:
124: smsw %ax
125: orb $1,%al
126: lmsw %ax
127: jmp 1f
128: nop
129:
130: /* step 3 reload segment descriptors */
131:
132: 1:
133: xorl %eax,%eax
134: movb $0x10,%al
135: movl %ax,%ds
136: movl %ax,%es
137: movl %ax,%ss
138: word
1.1.1.3 root 139: ljmp $0x8,$ BIOSRELOC+0xb3 /* would be nice if .-RELOC+0x7c00 worked */
1.1 root 140:
141: /* Global Descriptor Table contains three descriptors:
142: * 0x00: Null: not used
143: * 0x08: Code: code segment starts at 0 and extents for 4 gigabytes
144: * 0x10: Data: data segment starts at 0 and extends for 4 gigabytes
145: * (overlays code)
146: */
147: GDT:
148: NullDesc: .word 0,0,0,0 # null descriptor - not used
149: CodeDesc: .word 0xFFFF # limit at maximum: (bits 15:0)
150: .byte 0,0,0 # base at 0: (bits 23:0)
151: .byte 0x9f # present/priv level 0/code/conforming/readable
152: .byte 0xcf # page granular/default 32-bit/limit(bits 19:16)
153: .byte 0 # base at 0: (bits 31:24)
154: DataDesc: .word 0xFFFF # limit at maximum: (bits 15:0)
155: .byte 0,0,0 # base at 0: (bits 23:0)
156: .byte 0x93 # present/priv level 0/data/expand-up/writeable
157: .byte 0xcf # page granular/default 32-bit/limit(bits 19:16)
158: .byte 0 # base at 0: (bits 31:24)
159:
160: /* Global Descriptor Table pointer
161: * contains 6-byte pointer information for LGDT
162: */
163: GDTptr: .word 0x17 # limit to three 8 byte selectors(null,code,data)
1.1.1.3 root 164: .long BIOSRELOC+0x8c # GDT -- arrgh, gas again!
1.1 root 165: readcmd: .byte 0xe6,0,0,0,0,2,18,0x1b,0xff
166:
167: /* step 4 relocate to final bootstrap address. */
168: reloc:
169: movl $ BIOSRELOC,%esi
170: movl $ RELOC,%edi
171: movl $512,%ecx
172: rep
173: movsb
1.1.1.3 root 174: movl $0xa0000, %esp
1.1 root 175: pushl $dodisk
176: ret
177:
178: /* step 5 load remaining 15 sectors off disk */
179: dodisk:
1.1.1.3 root 180: movl $ RELOC+0x200, %edi
181: xorl %ebx, %ebx
182: incb %bl # shl $1,%bl
1.1 root 183: incb %bl
184: movb $0x20,%al # do a eoi
185: outb %al,$0x20
186:
187: NOP
1.1.1.4 root 188: movb $0xbf,%al # enable floppy interrupt, mask out rest
1.1 root 189: outb %al,$0x21
190: NOP
191: 8:
192: movb %bl,readcmd+4
193: movl %edi,%ecx
194:
195: /* Set read/write bytes */
196: xorl %edx,%edx
1.1.1.4 root 197: movb $0x0c,%dl # outb(0xC,junk); outb(0xB,0x46);
198: outb %al,%dx # reset DMA controller first/last flip-flop
1.1 root 199: NOP
200: decb %dx
1.1.1.4 root 201: movb $0x46,%al # single mode, write mem, chan 2
202: outb %al,%dx # output DMA controller mode byte
1.1 root 203:
204: /* Send start address */
205: movb $0x04,%dl # outb(0x4, addr);
206: movb %cl,%al
207: outb %al,%dx
208: NOP
209: movb %ch,%al # outb(0x4, addr>>8);
210: outb %al,%dx
211: NOP
212: rorl $8,%ecx # outb(0x81, addr>>16);
213: movb %ch,%al
214: outb %al,$0x81
215: NOP
216:
217: /* Send count */
218: movb $0x05,%dl # outb(0x5, 0);
219: xorl %eax,%eax
220: outb %al,%dx
221: NOP
222: movb $2,%al # outb(0x5,2);
223: outb %al,%dx
224: NOP
225:
226: /* set channel 2 */
1.1.1.3 root 227: movb $2,%al # outb(0x0A,2);
1.1 root 228: outb %al,$0x0A
229: NOP
230:
231: /* issue read command to fdc */
232: movw $0x3f4,%dx
233: movl $readcmd,%esi
234: xorl %ecx,%ecx
235: movb $9,%cl
236:
1.1.1.3 root 237: 2: NOP
238: inb %dx,%al
1.1 root 239: testb $0x80,%al
240: jz 2b
241:
242: incb %dx
1.1.1.3 root 243: NOP
1.1 root 244: movl (%esi),%al
245: outb %al,%dx
246: NOP
247: incl %esi
248: decb %dx
249: loop 2b
250:
251: /* watch the icu looking for an interrupt signalling completion */
252: xorl %edx,%edx
253: movb $0x20,%dl
1.1.1.3 root 254: 2:
255: NOP
256: movb $0xc,%al
1.1 root 257: outb %al,%dx
258: NOP
259: inb %dx,%al
260: andb $0x7f,%al
261: cmpb $6,%al
262: jne 2b
1.1.1.3 root 263: NOP
1.1 root 264: movb $0x20,%al # do a eoi
265: outb %al,%dx
266: NOP
267:
268: movl $0x3f4,%edx
269: xorl %ecx,%ecx
270: movb $7,%cl
1.1.1.3 root 271: 2:
1.1 root 272: NOP
1.1.1.3 root 273: inb %dx,%al
1.1 root 274: andb $0xC0,%al
275: cmpb $0xc0,%al
276: jne 2b
277: incb %dx
278: inb %dx,%al
279: decb %dx
280: loop 2b
281:
282: /* extract the status bytes after the read. must we do this? */
283: addw $0x200,%edi # next addr to load to
284: incb %bl
1.1.1.2 root 285: cmpb $15,%bl
1.1 root 286: jle 8b
287:
288: /* for clever bootstrap, dig out boot unit and cylinder */
289: pushl $0
290: pushl $0
291:
292: /* fd controller is major device 2 */
293: pushl $2 /* dev */
294:
295: /* sorry, no flags at this point! */
296:
1.1.1.3 root 297: movl $ start, %eax
298: call %eax /* main (dev, unit, off) */
1.1 root 299:
300: ebootblkcode:
301:
302: /* remaining space usable for a disk label */
303:
1.1.1.3 root 304: .org 0x1fe
1.1 root 305: .word 0xaa55 /* signature -- used by BIOS ROM */
306:
307: ebootblk: /* MUST BE EXACTLY 0x200 BIG FOR SURE */
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