// Support for booting from cdroms (the "El Torito" spec).
//
// Copyright (C) 2008,2009 Kevin O'Connor <kevin@koconnor.net>
// Copyright (C) 2002 MandrakeSoft S.A.
//
// This file may be distributed under the terms of the GNU LGPLv3 license.
#include "biosvar.h" // GET_GLOBAL
#include "block.h" // struct drive_s
#include "bregs.h" // struct bregs
#include "hw/ata.h" // ATA_CMD_REQUEST_SENSE
#include "hw/blockcmd.h" // CDB_CMD_REQUEST_SENSE
#include "malloc.h" // free
#include "output.h" // dprintf
#include "std/disk.h" // DISK_RET_SUCCESS
#include "string.h" // memset
#include "util.h" // cdrom_prepboot
// Locks for removable devices
u8 CDRom_locks[BUILD_MAX_EXTDRIVE] VARLOW;
/****************************************************************
* CD emulation
****************************************************************/
struct eltorito_s CDEmu VARLOW = { .size=sizeof(CDEmu) };
struct drive_s *emulated_drive_gf VARLOW;
struct drive_s *cdemu_drive_gf VARFSEG;
static int
cdemu_read(struct disk_op_s *op)
{
struct drive_s *drive_gf = GET_LOW(emulated_drive_gf);
struct disk_op_s dop;
dop.drive_gf = drive_gf;
dop.command = op->command;
dop.lba = GET_LOW(CDEmu.ilba) + op->lba / 4;
int count = op->count;
op->count = 0;
u8 *cdbuf_fl = GET_GLOBAL(bounce_buf_fl);
if (op->lba & 3) {
// Partial read of first block.
dop.count = 1;
dop.buf_fl = cdbuf_fl;
int ret = process_op(&dop);
if (ret)
return ret;
u8 thiscount = 4 - (op->lba & 3);
if (thiscount > count)
thiscount = count;
count -= thiscount;
memcpy_fl(op->buf_fl, cdbuf_fl + (op->lba & 3) * 512, thiscount * 512);
op->buf_fl += thiscount * 512;
op->count += thiscount;
dop.lba++;
}
if (count > 3) {
// Read n number of regular blocks.
dop.count = count / 4;
dop.buf_fl = op->buf_fl;
int ret = process_op(&dop);
op->count += dop.count * 4;
if (ret)
return ret;
u8 thiscount = count & ~3;
count &= 3;
op->buf_fl += thiscount * 512;
dop.lba += thiscount / 4;
}
if (count) {
// Partial read on last block.
dop.count = 1;
dop.buf_fl = cdbuf_fl;
int ret = process_op(&dop);
if (ret)
return ret;
u8 thiscount = count;
memcpy_fl(op->buf_fl, cdbuf_fl, thiscount * 512);
op->count += thiscount;
}
return DISK_RET_SUCCESS;
}
int
process_cdemu_op(struct disk_op_s *op)
{
if (!CONFIG_CDROM_EMU)
return 0;
switch (op->command) {
case CMD_READ:
return cdemu_read(op);
case CMD_WRITE:
case CMD_FORMAT:
return DISK_RET_EWRITEPROTECT;
case CMD_VERIFY:
case CMD_RESET:
case CMD_SEEK:
case CMD_ISREADY:
return DISK_RET_SUCCESS;
default:
return DISK_RET_EPARAM;
}
}
void
cdrom_prepboot(void)
{
if (!CONFIG_CDROM_EMU)
return;
if (!CDCount)
return;
if (create_bounce_buf() < 0)
return;
struct drive_s *drive = malloc_fseg(sizeof(*drive));
if (!drive) {
warn_noalloc();
free(drive);
return;
}
cdemu_drive_gf = drive;
memset(drive, 0, sizeof(*drive));
drive->type = DTYPE_CDEMU;
drive->blksize = DISK_SECTOR_SIZE;
drive->sectors = (u64)-1;
}
/****************************************************************
* CD booting
****************************************************************/
int
cdrom_boot(struct drive_s *drive)
{
ASSERT32FLAT();
struct disk_op_s dop;
int cdid = getDriveId(EXTTYPE_CD, drive);
memset(&dop, 0, sizeof(dop));
dop.drive_gf = drive;
if (!dop.drive_gf || cdid < 0)
return 1;
int ret = scsi_is_ready(&dop);
if (ret)
dprintf(1, "scsi_is_ready returned %d\n", ret);
// Read the Boot Record Volume Descriptor
u8 buffer[CDROM_SECTOR_SIZE];
dop.command = CMD_READ;
dop.lba = 0x11;
dop.count = 1;
dop.buf_fl = buffer;
ret = scsi_process_op(&dop);
if (ret)
return 3;
// Validity checks
if (buffer[0])
return 4;
if (strcmp((char*)&buffer[1], "CD001\001EL TORITO SPECIFICATION") != 0)
return 5;
// ok, now we calculate the Boot catalog address
u32 lba = *(u32*)&buffer[0x47];
// And we read the Boot Catalog
dop.lba = lba;
dop.count = 1;
ret = scsi_process_op(&dop);
if (ret)
return 7;
// Validation entry
if (buffer[0x00] != 0x01)
return 8; // Header
if (buffer[0x01] != 0x00)
return 9; // Platform
if (buffer[0x1E] != 0x55)
return 10; // key 1
if (buffer[0x1F] != 0xAA)
return 10; // key 2
// Initial/Default Entry
if (buffer[0x20] != 0x88)
return 11; // Bootable
// Fill in el-torito cdrom emulation fields.
emulated_drive_gf = drive;
u8 media = buffer[0x21];
u16 boot_segment = *(u16*)&buffer[0x22];
if (!boot_segment)
boot_segment = 0x07C0;
CDEmu.load_segment = boot_segment;
CDEmu.buffer_segment = 0x0000;
u16 nbsectors = *(u16*)&buffer[0x26];
CDEmu.sector_count = nbsectors;
lba = *(u32*)&buffer[0x28];
CDEmu.ilba = lba;
CDEmu.controller_index = drive->cntl_id / 2;
CDEmu.device_spec = drive->cntl_id % 2;
// And we read the image in memory
nbsectors = DIV_ROUND_UP(nbsectors, 4);
dop.lba = lba;
dop.buf_fl = MAKE_FLATPTR(boot_segment, 0);
while (nbsectors) {
int count = nbsectors;
if (count > 64*1024/CDROM_SECTOR_SIZE)
count = 64*1024/CDROM_SECTOR_SIZE;
dop.count = count;
ret = scsi_process_op(&dop);
if (ret)
return 12;
nbsectors -= count;
dop.lba += count;
dop.buf_fl += count*CDROM_SECTOR_SIZE;
}
if (media == 0) {
// No emulation requested - return success.
CDEmu.emulated_drive = EXTSTART_CD + cdid;
return 0;
}
// Emulation of a floppy/harddisk requested
if (! CONFIG_CDROM_EMU || !cdemu_drive_gf)
return 13;
// Set emulated drive id and increase bios installed hardware
// number of devices
if (media < 4) {
// Floppy emulation
CDEmu.emulated_drive = 0x00;
// XXX - get and set actual floppy count.
set_equipment_flags(0x41, 0x41);
switch (media) {
case 0x01: // 1.2M floppy
CDEmu.chs.sptcyl = 15;
CDEmu.chs.cyllow = 79;
CDEmu.chs.heads = 1;
break;
case 0x02: // 1.44M floppy
CDEmu.chs.sptcyl = 18;
CDEmu.chs.cyllow = 79;
CDEmu.chs.heads = 1;
break;
case 0x03: // 2.88M floppy
CDEmu.chs.sptcyl = 36;
CDEmu.chs.cyllow = 79;
CDEmu.chs.heads = 1;
break;
}
} else {
// Harddrive emulation
CDEmu.emulated_drive = 0x80;
SET_BDA(hdcount, GET_BDA(hdcount) + 1);
// Peak at partition table to get chs.
struct mbr_s *mbr = MAKE_FLATPTR(boot_segment, 0);
CDEmu.chs = mbr->partitions[0].last;
}
// everything is ok, so from now on, the emulation is active
CDEmu.media = media;
dprintf(6, "cdemu media=%d\n", media);
return 0;
}