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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'Connor7a558e42008-03-11 20:38:33 -040066 irq_enable();
67
Kevin O'Connor56a506d2008-03-29 13:15:36 -040068 SET_EBDA(ipl.sequence, seq_nr);
Kevin O'Connor7a558e42008-03-11 20:38:33 -040069
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050070 u16 bootseg;
Kevin O'Connorf076a3e2008-02-25 22:25:15 -050071 u8 bootdrv = 0;
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050072 u16 bootdev, bootip;
Kevin O'Connorf076a3e2008-02-25 22:25:15 -050073
Kevin O'Connor840c5342008-03-29 14:04:34 -040074 bootdev = inb_cmos(CMOS_BIOS_BOOTFLAG2);
75 bootdev |= ((inb_cmos(CMOS_BIOS_BOOTFLAG1) & 0xf0) << 4);
76 bootdev >>= 4 * seq_nr;
77 bootdev &= 0xf;
78 if (bootdev == 0)
79 BX_PANIC("No bootable device.\n");
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050080
Kevin O'Connor840c5342008-03-29 14:04:34 -040081 /* Translate from CMOS runes to an IPL table offset by subtracting 1 */
82 bootdev -= 1;
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050083
Kevin O'Connor56a506d2008-03-29 13:15:36 -040084 if (bootdev >= GET_EBDA(ipl.count)) {
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050085 BX_INFO("Invalid boot device (0x%x)\n", bootdev);
86 return;
87 }
Kevin O'Connor56a506d2008-03-29 13:15:36 -040088 u16 type = GET_EBDA(ipl.table[bootdev].type);
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050089
90 /* Do the loading, and set up vector as a far pointer to the boot
91 * address, and bootdrv as the boot drive */
92 print_boot_device(type);
93
Kevin O'Connorf076a3e2008-02-25 22:25:15 -050094 struct bregs cr;
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050095 switch(type) {
96 case IPL_TYPE_FLOPPY: /* FDD */
97 case IPL_TYPE_HARDDISK: /* HDD */
Kevin O'Connorf076a3e2008-02-25 22:25:15 -050098
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -050099 bootdrv = (type == IPL_TYPE_HARDDISK) ? 0x80 : 0x00;
100 bootseg = 0x07c0;
101
102 // Read sector
103 memset(&cr, 0, sizeof(cr));
104 cr.dl = bootdrv;
105 cr.es = bootseg;
106 cr.ah = 2;
107 cr.al = 1;
108 cr.cl = 1;
109 call16_int(0x13, &cr);
110
111 if (cr.flags & F_CF) {
112 print_boot_failure(type, 1);
113 return;
114 }
115
116 /* Always check the signature on a HDD boot sector; on FDD,
117 * only do the check if the CMOS doesn't tell us to skip it */
118 if ((type != IPL_TYPE_FLOPPY)
119 || !((inb_cmos(CMOS_BIOS_BOOTFLAG1) & 0x01))) {
120 if (GET_FARVAR(bootseg, *(u16*)0x1fe) != 0xaa55) {
121 print_boot_failure(type, 0);
122 return;
123 }
124 }
125
126 /* Canonicalize bootseg:bootip */
127 bootip = (bootseg & 0x0fff) << 4;
128 bootseg &= 0xf000;
129 break;
Kevin O'Connor180a9592008-03-04 22:50:53 -0500130 case IPL_TYPE_CDROM: {
131 /* CD-ROM */
132 if (! CONFIG_CDROM_BOOT)
133 break;
134 u16 status = cdrom_boot();
135 if (status) {
136 printf("CDROM boot failure code : %04x\n", status);
137 print_boot_failure(type, 1);
138 return;
139 }
140
141 bootdrv = GET_EBDA(cdemu.emulated_drive);
142 bootseg = GET_EBDA(cdemu.load_segment);
143 /* Canonicalize bootseg:bootip */
144 bootip = (bootseg & 0x0fff) << 4;
145 bootseg &= 0xf000;
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500146 break;
Kevin O'Connor180a9592008-03-04 22:50:53 -0500147 }
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500148 case IPL_TYPE_BEV: {
149 /* Expansion ROM with a Bootstrap Entry Vector (a far
150 * pointer) */
Kevin O'Connor56a506d2008-03-29 13:15:36 -0400151 u32 vector = GET_EBDA(ipl.table[bootdev].vector);
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500152 bootseg = vector >> 16;
153 bootip = vector & 0xffff;
154 break;
155 }
156 default:
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500157 return;
158 }
159
Kevin O'Connordcc7a4f2008-03-08 23:25:16 -0500160 /* Debugging info */
161 BX_INFO("Booting from %x:%x\n", bootseg, bootip);
162
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500163 memset(&cr, 0, sizeof(cr));
164 cr.ip = bootip;
165 cr.cs = bootseg;
166 // Set the magic number in ax and the boot drive in dl.
167 cr.dl = bootdrv;
168 cr.ax = 0xaa55;
169 call16(&cr);
Kevin O'Connor7af49bf2008-03-09 13:46:13 -0400170}
171
172static void
173do_boot(u16 seq_nr)
174{
175 try_boot(seq_nr);
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500176
Kevin O'Connor38fcbfe2008-02-25 22:30:47 -0500177 // Boot failed: invoke the boot recovery function
Kevin O'Connor7af49bf2008-03-09 13:46:13 -0400178 struct bregs br;
179 memset(&br, 0, sizeof(br));
180 call16_int(0x18, &br);
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);
Kevin O'Connor56a506d2008-03-29 13:15:36 -0400188 u16 seq = GET_EBDA(ipl.sequence) + 1;
Kevin O'Connor7af49bf2008-03-09 13:46:13 -0400189 do_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);
Kevin O'Connor7af49bf2008-03-09 13:46:13 -0400197 do_boot(0);
Kevin O'Connorf076a3e2008-02-25 22:25:15 -0500198}