| // 16bit code to load disk image and start system boot. |
| // |
| // Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net> |
| // Copyright (C) 2002 MandrakeSoft S.A. |
| // |
| // This file may be distributed under the terms of the GNU GPLv3 license. |
| |
| #include "util.h" // irq_enable |
| #include "biosvar.h" // struct bregs |
| #include "config.h" // CONFIG_* |
| #include "cmos.h" // inb_cmos |
| #include "ata.h" // ata_detect |
| #include "disk.h" // cdrom_boot |
| |
| // We need a copy of this string, but we are not actually a PnP BIOS, |
| // so make sure it is *not* aligned, so OSes will not see it if they |
| // scan. |
| char pnp_string[] VISIBLE __attribute__((aligned (2))) = " $PnP"; |
| |
| //-------------------------------------------------------------------------- |
| // print_boot_device |
| // displays the boot device |
| //-------------------------------------------------------------------------- |
| |
| static const char drivetypes[][10]={ |
| "", "Floppy","Hard Disk","CD-Rom", "Network" |
| }; |
| |
| static void |
| print_boot_device(u16 type) |
| { |
| /* NIC appears as type 0x80 */ |
| if (type == IPL_TYPE_BEV) |
| type = 0x4; |
| if (type == 0 || type > 0x4) |
| BX_PANIC("Bad drive type\n"); |
| printf("Booting from %s...\n", drivetypes[type]); |
| |
| // XXX - latest cvs has BEV description |
| } |
| |
| //-------------------------------------------------------------------------- |
| // print_boot_failure |
| // displays the reason why boot failed |
| //-------------------------------------------------------------------------- |
| static void |
| print_boot_failure(u16 type, u8 reason) |
| { |
| if (type == 0 || type > 0x3) |
| BX_PANIC("Bad drive type\n"); |
| |
| printf("Boot failed"); |
| if (type < 4) { |
| /* Report the reason too */ |
| if (reason==0) |
| printf(": not a bootable disk"); |
| else |
| printf(": could not read the boot disk"); |
| } |
| printf("\n\n"); |
| } |
| |
| static void |
| try_boot(u16 seq_nr) |
| { |
| SET_IPL(sequence, seq_nr); |
| u16 bootseg; |
| u8 bootdrv = 0; |
| u16 bootdev, bootip; |
| |
| if (CONFIG_CDROM_BOOT) { |
| bootdev = inb_cmos(CMOS_BIOS_BOOTFLAG2); |
| bootdev |= ((inb_cmos(CMOS_BIOS_BOOTFLAG1) & 0xf0) << 4); |
| bootdev >>= 4 * seq_nr; |
| bootdev &= 0xf; |
| if (bootdev == 0) |
| BX_PANIC("No bootable device.\n"); |
| |
| /* Translate from CMOS runes to an IPL table offset by subtracting 1 */ |
| bootdev -= 1; |
| } else { |
| if (seq_nr ==2) |
| BX_PANIC("No more boot devices."); |
| if (!!(inb_cmos(CMOS_BIOS_CONFIG) & 0x20) ^ (seq_nr == 1)) |
| /* Boot from floppy if the bit is set or it's the second boot */ |
| bootdev = 0x00; |
| else |
| bootdev = 0x01; |
| } |
| |
| if (bootdev >= GET_IPL(count)) { |
| BX_INFO("Invalid boot device (0x%x)\n", bootdev); |
| return; |
| } |
| u16 type = GET_IPL(table[bootdev].type); |
| |
| /* Do the loading, and set up vector as a far pointer to the boot |
| * address, and bootdrv as the boot drive */ |
| print_boot_device(type); |
| |
| struct bregs cr; |
| switch(type) { |
| case IPL_TYPE_FLOPPY: /* FDD */ |
| case IPL_TYPE_HARDDISK: /* HDD */ |
| |
| bootdrv = (type == IPL_TYPE_HARDDISK) ? 0x80 : 0x00; |
| bootseg = 0x07c0; |
| |
| // Read sector |
| memset(&cr, 0, sizeof(cr)); |
| cr.dl = bootdrv; |
| cr.es = bootseg; |
| cr.ah = 2; |
| cr.al = 1; |
| cr.cl = 1; |
| call16_int(0x13, &cr); |
| |
| if (cr.flags & F_CF) { |
| print_boot_failure(type, 1); |
| return; |
| } |
| |
| /* Always check the signature on a HDD boot sector; on FDD, |
| * only do the check if the CMOS doesn't tell us to skip it */ |
| if ((type != IPL_TYPE_FLOPPY) |
| || !((inb_cmos(CMOS_BIOS_BOOTFLAG1) & 0x01))) { |
| if (GET_FARVAR(bootseg, *(u16*)0x1fe) != 0xaa55) { |
| print_boot_failure(type, 0); |
| return; |
| } |
| } |
| |
| /* Canonicalize bootseg:bootip */ |
| bootip = (bootseg & 0x0fff) << 4; |
| bootseg &= 0xf000; |
| break; |
| case IPL_TYPE_CDROM: { |
| /* CD-ROM */ |
| if (! CONFIG_CDROM_BOOT) |
| break; |
| u16 status = cdrom_boot(); |
| if (status) { |
| printf("CDROM boot failure code : %04x\n", status); |
| print_boot_failure(type, 1); |
| return; |
| } |
| |
| bootdrv = GET_EBDA(cdemu.emulated_drive); |
| bootseg = GET_EBDA(cdemu.load_segment); |
| /* Canonicalize bootseg:bootip */ |
| bootip = (bootseg & 0x0fff) << 4; |
| bootseg &= 0xf000; |
| break; |
| } |
| case IPL_TYPE_BEV: { |
| /* Expansion ROM with a Bootstrap Entry Vector (a far |
| * pointer) */ |
| u32 vector = GET_IPL(table[bootdev].vector); |
| bootseg = vector >> 16; |
| bootip = vector & 0xffff; |
| break; |
| } |
| default: |
| return; |
| } |
| |
| memset(&cr, 0, sizeof(cr)); |
| cr.ip = bootip; |
| cr.cs = bootseg; |
| // Set the magic number in ax and the boot drive in dl. |
| cr.dl = bootdrv; |
| cr.ax = 0xaa55; |
| call16(&cr); |
| |
| // Boot failed: invoke the boot recovery function |
| memset(&cr, 0, sizeof(cr)); |
| call16_int(0x18, &cr); |
| } |
| |
| // Boot Failure recovery: try the next device. |
| void VISIBLE |
| handle_18() |
| { |
| debug_enter(NULL); |
| u16 seq = GET_IPL(sequence) + 1; |
| try_boot(seq); |
| } |
| |
| // INT 19h Boot Load Service Entry Point |
| void VISIBLE |
| handle_19() |
| { |
| debug_enter(NULL); |
| try_boot(0); |
| } |
| |
| // Called from 32bit code - start boot process |
| void VISIBLE |
| begin_boot() |
| { |
| if (CONFIG_ATA) |
| ata_detect(); |
| irq_enable(); |
| struct bregs br; |
| memset(&br, 0, sizeof(br)); |
| call16_int(0x19, &br); |
| } |