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Kevin O'Connorf076a3e2008-02-25 22:25:15 -05001// 16bit code to load disk image and start system boot.
2//
3// Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
4// Copyright (C) 2002 MandrakeSoft S.A.
5//
6// This file may be distributed under the terms of the GNU GPLv3 license.
7
Kevin O'Connorf076a3e2008-02-25 22:25:15 -05008#include "util.h" // irq_enable
9#include "biosvar.h" // struct bregs
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050010#include "config.h" // CONFIG_*
11#include "cmos.h" // inb_cmos
Kevin O'Connor15aee2e2008-03-01 13:34:04 -050012#include "ata.h" // ata_detect
Kevin O'Connor180a9592008-03-04 22:50:53 -050013#include "disk.h" // cdrom_boot
Kevin O'Connorf076a3e2008-02-25 22:25:15 -050014
Kevin O'Connor44c631d2008-03-02 11:24:36 -050015// We need a copy of this string, but we are not actually a PnP BIOS,
16// so make sure it is *not* aligned, so OSes will not see it if they
17// scan.
Kevin O'Connor19786762008-03-05 21:09:59 -050018char pnp_string[] VISIBLE16 __attribute__((aligned (2))) = " $PnP";
Kevin O'Connor44c631d2008-03-02 11:24:36 -050019
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050020//--------------------------------------------------------------------------
21// print_boot_device
22// displays the boot device
23//--------------------------------------------------------------------------
24
25static const char drivetypes[][10]={
26 "", "Floppy","Hard Disk","CD-Rom", "Network"
27};
28
29static void
30print_boot_device(u16 type)
Kevin O'Connorf076a3e2008-02-25 22:25:15 -050031{
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050032 /* NIC appears as type 0x80 */
33 if (type == IPL_TYPE_BEV)
34 type = 0x4;
35 if (type == 0 || type > 0x4)
36 BX_PANIC("Bad drive type\n");
37 printf("Booting from %s...\n", drivetypes[type]);
Kevin O'Connora2e73802008-02-27 10:27:00 -050038
39 // XXX - latest cvs has BEV description
Kevin O'Connorf076a3e2008-02-25 22:25:15 -050040}
41
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050042//--------------------------------------------------------------------------
43// print_boot_failure
44// displays the reason why boot failed
45//--------------------------------------------------------------------------
46static void
47print_boot_failure(u16 type, u8 reason)
Kevin O'Connorf076a3e2008-02-25 22:25:15 -050048{
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050049 if (type == 0 || type > 0x3)
50 BX_PANIC("Bad drive type\n");
51
Kevin O'Connora2e73802008-02-27 10:27:00 -050052 printf("Boot failed");
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050053 if (type < 4) {
54 /* Report the reason too */
55 if (reason==0)
56 printf(": not a bootable disk");
57 else
58 printf(": could not read the boot disk");
59 }
Kevin O'Connora2e73802008-02-27 10:27:00 -050060 printf("\n\n");
Kevin O'Connorf076a3e2008-02-25 22:25:15 -050061}
62
63static void
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050064try_boot(u16 seq_nr)
Kevin O'Connorf076a3e2008-02-25 22:25:15 -050065{
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050066 SET_IPL(sequence, seq_nr);
67 u16 bootseg;
Kevin O'Connorf076a3e2008-02-25 22:25:15 -050068 u8 bootdrv = 0;
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050069 u16 bootdev, bootip;
Kevin O'Connorf076a3e2008-02-25 22:25:15 -050070
Kevin O'Connor180a9592008-03-04 22:50:53 -050071 if (CONFIG_CDROM_BOOT) {
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050072 bootdev = inb_cmos(CMOS_BIOS_BOOTFLAG2);
73 bootdev |= ((inb_cmos(CMOS_BIOS_BOOTFLAG1) & 0xf0) << 4);
74 bootdev >>= 4 * seq_nr;
75 bootdev &= 0xf;
76 if (bootdev == 0)
77 BX_PANIC("No bootable device.\n");
78
79 /* Translate from CMOS runes to an IPL table offset by subtracting 1 */
80 bootdev -= 1;
81 } else {
82 if (seq_nr ==2)
83 BX_PANIC("No more boot devices.");
84 if (!!(inb_cmos(CMOS_BIOS_CONFIG) & 0x20) ^ (seq_nr == 1))
85 /* Boot from floppy if the bit is set or it's the second boot */
86 bootdev = 0x00;
87 else
88 bootdev = 0x01;
89 }
90
91 if (bootdev >= GET_IPL(count)) {
92 BX_INFO("Invalid boot device (0x%x)\n", bootdev);
93 return;
94 }
95 u16 type = GET_IPL(table[bootdev].type);
96
97 /* Do the loading, and set up vector as a far pointer to the boot
98 * address, and bootdrv as the boot drive */
99 print_boot_device(type);
100
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500101 struct bregs cr;
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500102 switch(type) {
103 case IPL_TYPE_FLOPPY: /* FDD */
104 case IPL_TYPE_HARDDISK: /* HDD */
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500105
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500106 bootdrv = (type == IPL_TYPE_HARDDISK) ? 0x80 : 0x00;
107 bootseg = 0x07c0;
108
109 // Read sector
110 memset(&cr, 0, sizeof(cr));
111 cr.dl = bootdrv;
112 cr.es = bootseg;
113 cr.ah = 2;
114 cr.al = 1;
115 cr.cl = 1;
116 call16_int(0x13, &cr);
117
118 if (cr.flags & F_CF) {
119 print_boot_failure(type, 1);
120 return;
121 }
122
123 /* Always check the signature on a HDD boot sector; on FDD,
124 * only do the check if the CMOS doesn't tell us to skip it */
125 if ((type != IPL_TYPE_FLOPPY)
126 || !((inb_cmos(CMOS_BIOS_BOOTFLAG1) & 0x01))) {
127 if (GET_FARVAR(bootseg, *(u16*)0x1fe) != 0xaa55) {
128 print_boot_failure(type, 0);
129 return;
130 }
131 }
132
133 /* Canonicalize bootseg:bootip */
134 bootip = (bootseg & 0x0fff) << 4;
135 bootseg &= 0xf000;
136 break;
Kevin O'Connor180a9592008-03-04 22:50:53 -0500137 case IPL_TYPE_CDROM: {
138 /* CD-ROM */
139 if (! CONFIG_CDROM_BOOT)
140 break;
141 u16 status = cdrom_boot();
142 if (status) {
143 printf("CDROM boot failure code : %04x\n", status);
144 print_boot_failure(type, 1);
145 return;
146 }
147
148 bootdrv = GET_EBDA(cdemu.emulated_drive);
149 bootseg = GET_EBDA(cdemu.load_segment);
150 /* Canonicalize bootseg:bootip */
151 bootip = (bootseg & 0x0fff) << 4;
152 bootseg &= 0xf000;
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500153 break;
Kevin O'Connor180a9592008-03-04 22:50:53 -0500154 }
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500155 case IPL_TYPE_BEV: {
156 /* Expansion ROM with a Bootstrap Entry Vector (a far
157 * pointer) */
158 u32 vector = GET_IPL(table[bootdev].vector);
159 bootseg = vector >> 16;
160 bootip = vector & 0xffff;
161 break;
162 }
163 default:
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500164 return;
165 }
166
Kevin O'Connordcc7a4f2008-03-08 23:25:16 -0500167 /* Debugging info */
168 BX_INFO("Booting from %x:%x\n", bootseg, bootip);
169
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500170 memset(&cr, 0, sizeof(cr));
171 cr.ip = bootip;
172 cr.cs = bootseg;
173 // Set the magic number in ax and the boot drive in dl.
174 cr.dl = bootdrv;
175 cr.ax = 0xaa55;
176 call16(&cr);
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500177
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500178 // Boot failed: invoke the boot recovery function
179 memset(&cr, 0, sizeof(cr));
180 call16_int(0x18, &cr);
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500181}
182
183// Boot Failure recovery: try the next device.
Kevin O'Connor19786762008-03-05 21:09:59 -0500184void VISIBLE16
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500185handle_18()
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500186{
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500187 debug_enter(NULL);
188 u16 seq = GET_IPL(sequence) + 1;
189 try_boot(seq);
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500190}
191
192// INT 19h Boot Load Service Entry Point
Kevin O'Connor19786762008-03-05 21:09:59 -0500193void VISIBLE16
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500194handle_19()
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500195{
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500196 debug_enter(NULL);
197 try_boot(0);
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500198}
199
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500200// Called from 32bit code - start boot process
Kevin O'Connor19786762008-03-05 21:09:59 -0500201void VISIBLE16
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500202begin_boot()
203{
Kevin O'Connorc65a3802008-03-02 13:58:23 -0500204 if (CONFIG_ATA)
205 ata_detect();
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500206 irq_enable();
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500207 struct bregs br;
208 memset(&br, 0, sizeof(br));
209 call16_int(0x19, &br);
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500210}