1 // 16bit code to load disk image and start system boot.
3 // Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
4 // Copyright (C) 2002 MandrakeSoft S.A.
6 // This file may be distributed under the terms of the GNU GPLv3 license.
8 #include "util.h" // irq_enable
9 #include "biosvar.h" // struct bregs
10 #include "config.h" // CONFIG_*
11 #include "cmos.h" // inb_cmos
12 #include "ata.h" // ata_detect
14 //--------------------------------------------------------------------------
16 // displays the boot device
17 //--------------------------------------------------------------------------
19 static const char drivetypes[][10]={
20 "", "Floppy","Hard Disk","CD-Rom", "Network"
24 print_boot_device(u16 type)
26 /* NIC appears as type 0x80 */
27 if (type == IPL_TYPE_BEV)
29 if (type == 0 || type > 0x4)
30 BX_PANIC("Bad drive type\n");
31 printf("Booting from %s...\n", drivetypes[type]);
33 // XXX - latest cvs has BEV description
36 //--------------------------------------------------------------------------
38 // displays the reason why boot failed
39 //--------------------------------------------------------------------------
41 print_boot_failure(u16 type, u8 reason)
43 if (type == 0 || type > 0x3)
44 BX_PANIC("Bad drive type\n");
46 printf("Boot failed");
48 /* Report the reason too */
50 printf(": not a bootable disk");
52 printf(": could not read the boot disk");
60 SET_IPL(sequence, seq_nr);
65 if (CONFIG_ELTORITO_BOOT) {
66 bootdev = inb_cmos(CMOS_BIOS_BOOTFLAG2);
67 bootdev |= ((inb_cmos(CMOS_BIOS_BOOTFLAG1) & 0xf0) << 4);
68 bootdev >>= 4 * seq_nr;
71 BX_PANIC("No bootable device.\n");
73 /* Translate from CMOS runes to an IPL table offset by subtracting 1 */
77 BX_PANIC("No more boot devices.");
78 if (!!(inb_cmos(CMOS_BIOS_CONFIG) & 0x20) ^ (seq_nr == 1))
79 /* Boot from floppy if the bit is set or it's the second boot */
85 if (bootdev >= GET_IPL(count)) {
86 BX_INFO("Invalid boot device (0x%x)\n", bootdev);
89 u16 type = GET_IPL(table[bootdev].type);
91 /* Do the loading, and set up vector as a far pointer to the boot
92 * address, and bootdrv as the boot drive */
93 print_boot_device(type);
97 case IPL_TYPE_FLOPPY: /* FDD */
98 case IPL_TYPE_HARDDISK: /* HDD */
100 bootdrv = (type == IPL_TYPE_HARDDISK) ? 0x80 : 0x00;
104 memset(&cr, 0, sizeof(cr));
110 call16_int(0x13, &cr);
112 if (cr.flags & F_CF) {
113 print_boot_failure(type, 1);
117 /* Always check the signature on a HDD boot sector; on FDD,
118 * only do the check if the CMOS doesn't tell us to skip it */
119 if ((type != IPL_TYPE_FLOPPY)
120 || !((inb_cmos(CMOS_BIOS_BOOTFLAG1) & 0x01))) {
121 if (GET_FARVAR(bootseg, *(u16*)0x1fe) != 0xaa55) {
122 print_boot_failure(type, 0);
127 /* Canonicalize bootseg:bootip */
128 bootip = (bootseg & 0x0fff) << 4;
131 case IPL_TYPE_CDROM: /* CD-ROM */
136 /* Expansion ROM with a Bootstrap Entry Vector (a far
138 u32 vector = GET_IPL(table[bootdev].vector);
139 bootseg = vector >> 16;
140 bootip = vector & 0xffff;
147 memset(&cr, 0, sizeof(cr));
150 // Set the magic number in ax and the boot drive in dl.
155 // Boot failed: invoke the boot recovery function
156 memset(&cr, 0, sizeof(cr));
157 call16_int(0x18, &cr);
160 // Boot Failure recovery: try the next device.
165 u16 seq = GET_IPL(sequence) + 1;
169 // INT 19h Boot Load Service Entry Point
177 // Called from 32bit code - start boot process
184 memset(&br, 0, sizeof(br));
185 call16_int(0x19, &br);