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freebsd-nq/sys/boot/i386/libi386/biosdisk.c
John Baldwin 3c3a6fe0e0 Add support for writing to BIOS disks. 
PR:		kern/32389
Submitted by:	Jonathan Mini <mini@haikugeek.com>
Sponsored by:	ClickArray, Inc.
2001-12-11 00:08:10 +00:00

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/*-
* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* BIOS disk device handling.
*
* Ideas and algorithms from:
*
* - NetBSD libi386/biosdisk.c
* - FreeBSD biosboot/disk.c
*
*/
#include <stand.h>
#include <sys/disklabel.h>
#include <sys/diskslice.h>
#include <sys/reboot.h>
#include <stdarg.h>
#include <bootstrap.h>
#include <btxv86.h>
#include "libi386.h"
#define BIOS_NUMDRIVES 0x475
#define BIOSDISK_SECSIZE 512
#define BUFSIZE (1 * BIOSDISK_SECSIZE)
#define MAXBDDEV MAXDEV
#define DT_ATAPI 0x10 /* disk type for ATAPI floppies */
#define WDMAJOR 0 /* major numbers for devices we frontend for */
#define WFDMAJOR 1
#define FDMAJOR 2
#define DAMAJOR 4
#ifdef DISK_DEBUG
# define DEBUG(fmt, args...) printf("%s: " fmt "\n" , __func__ , ## args)
#else
# define DEBUG(fmt, args...)
#endif
struct open_disk {
int od_dkunit; /* disk unit number */
int od_unit; /* BIOS unit number */
int od_cyl; /* BIOS geometry */
int od_hds;
int od_sec;
int od_boff; /* block offset from beginning of BIOS disk */
int od_flags;
#define BD_MODEINT13 0x0000
#define BD_MODEEDD1 0x0001
#define BD_MODEEDD3 0x0002
#define BD_MODEMASK 0x0003
#define BD_FLOPPY 0x0004
#define BD_LABELOK 0x0008
#define BD_PARTTABOK 0x0010
struct disklabel od_disklabel;
int od_nslices; /* slice count */
struct dos_partition od_slicetab[MAX_SLICES];
};
/*
* List of BIOS devices, translation from disk unit number to
* BIOS unit number.
*/
static struct bdinfo
{
int bd_unit; /* BIOS unit number */
int bd_flags;
int bd_type; /* BIOS 'drive type' (floppy only) */
} bdinfo [MAXBDDEV];
static int nbdinfo = 0;
static int bd_getgeom(struct open_disk *od);
static int bd_read(struct open_disk *od, daddr_t dblk, int blks,
caddr_t dest);
static int bd_write(struct open_disk *od, daddr_t dblk, int blks,
caddr_t dest);
static int bd_int13probe(struct bdinfo *bd);
static void bd_printslice(struct open_disk *od, struct dos_partition *dp,
char *prefix, int verbose);
static void bd_printbsdslice(struct open_disk *od, daddr_t offset,
char *prefix, int verbose);
static int bd_init(void);
static int bd_strategy(void *devdata, int flag, daddr_t dblk,
size_t size, char *buf, size_t *rsize);
static int bd_realstrategy(void *devdata, int flag, daddr_t dblk,
size_t size, char *buf, size_t *rsize);
static int bd_open(struct open_file *f, ...);
static int bd_close(struct open_file *f);
static void bd_print(int verbose);
struct devsw biosdisk = {
"disk",
DEVT_DISK,
bd_init,
bd_strategy,
bd_open,
bd_close,
noioctl,
bd_print,
NULL
};
static int bd_opendisk(struct open_disk **odp, struct i386_devdesc *dev);
static void bd_closedisk(struct open_disk *od);
static int bd_bestslice(struct open_disk *od);
static void bd_checkextended(struct open_disk *od, int slicenum);
/*
* Translate between BIOS device numbers and our private unit numbers.
*/
int
bd_bios2unit(int biosdev)
{
int i;
DEBUG("looking for bios device 0x%x", biosdev);
for (i = 0; i < nbdinfo; i++) {
DEBUG("bd unit %d is BIOS device 0x%x", i, bdinfo[i].bd_unit);
if (bdinfo[i].bd_unit == biosdev)
return(i);
}
return(-1);
}
int
bd_unit2bios(int unit)
{
if ((unit >= 0) && (unit < nbdinfo))
return(bdinfo[unit].bd_unit);
return(-1);
}
/*
* Quiz the BIOS for disk devices, save a little info about them.
*/
static int
bd_init(void)
{
int base, unit, nfd = 0;
/* sequence 0, 0x80 */
for (base = 0; base <= 0x80; base += 0x80) {
for (unit = base; (nbdinfo < MAXBDDEV); unit++) {
/* check the BIOS equipment list for number of fixed disks */
if((base == 0x80) &&
(nfd >= *(unsigned char *)PTOV(BIOS_NUMDRIVES)))
break;
bdinfo[nbdinfo].bd_unit = unit;
bdinfo[nbdinfo].bd_flags = (unit < 0x80) ? BD_FLOPPY : 0;
if (!bd_int13probe(&bdinfo[nbdinfo]))
break;
/* XXX we need "disk aliases" to make this simpler */
printf("BIOS drive %c: is disk%d\n",
(unit < 0x80) ? ('A' + unit) : ('C' + unit - 0x80), nbdinfo);
nbdinfo++;
if (base == 0x80)
nfd++;
}
}
return(0);
}
/*
* Try to detect a device supported by the legacy int13 BIOS
*/
static int
bd_int13probe(struct bdinfo *bd)
{
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0x800;
v86.edx = bd->bd_unit;
v86int();
if (!(v86.efl & 0x1) && /* carry clear */
((v86.edx & 0xff) > ((unsigned)bd->bd_unit & 0x7f))) { /* unit # OK */
bd->bd_flags |= BD_MODEINT13;
bd->bd_type = v86.ebx & 0xff;
/* Determine if we can use EDD with this device. */
v86.eax = 0x4100;
v86.edx = bd->bd_unit;
v86.ebx = 0x55aa;
v86int();
if (!(v86.efl & 0x1) && /* carry clear */
((v86.ebx & 0xffff) == 0xaa55) && /* signature */
(v86.ecx & 0x1)) { /* packets mode ok */
bd->bd_flags |= BD_MODEEDD1;
if((v86.eax & 0xff00) > 0x300)
bd->bd_flags |= BD_MODEEDD3;
}
return(1);
}
return(0);
}
/*
* Print information about disks
*/
static void
bd_print(int verbose)
{
int i, j;
char line[80];
struct i386_devdesc dev;
struct open_disk *od;
struct dos_partition *dptr;
for (i = 0; i < nbdinfo; i++) {
sprintf(line, " disk%d: BIOS drive %c:\n", i,
(bdinfo[i].bd_unit < 0x80) ? ('A' + bdinfo[i].bd_unit) : ('C' + bdinfo[i].bd_unit - 0x80));
pager_output(line);
/* try to open the whole disk */
dev.d_kind.biosdisk.unit = i;
dev.d_kind.biosdisk.slice = -1;
dev.d_kind.biosdisk.partition = -1;
if (!bd_opendisk(&od, &dev)) {
/* Do we have a partition table? */
if (od->od_flags & BD_PARTTABOK) {
dptr = &od->od_slicetab[0];
/* Check for a "dedicated" disk */
if ((dptr[3].dp_typ == DOSPTYP_386BSD) &&
(dptr[3].dp_start == 0) &&
(dptr[3].dp_size == 50000)) {
sprintf(line, " disk%d", i);
bd_printbsdslice(od, 0, line, verbose);
} else {
for (j = 0; j < od->od_nslices; j++) {
sprintf(line, " disk%ds%d", i, j + 1);
bd_printslice(od, &dptr[j], line, verbose);
}
}
}
bd_closedisk(od);
}
}
}
/*
* Print information about slices on a disk. For the size calculations we
* assume a 512 byte sector.
*/
static void
bd_printslice(struct open_disk *od, struct dos_partition *dp, char *prefix,
int verbose)
{
char line[80];
switch (dp->dp_typ) {
case DOSPTYP_386BSD:
bd_printbsdslice(od, (daddr_t)dp->dp_start, prefix, verbose);
return;
case DOSPTYP_LINSWP:
if (verbose)
sprintf(line, "%s: Linux swap %.6dMB (%d - %d)\n",
prefix, dp->dp_size / 2048,
dp->dp_start, dp->dp_start + dp->dp_size);
else
sprintf(line, "%s: Linux swap\n", prefix);
break;
case DOSPTYP_LINUX:
/*
* XXX
* read the superblock to confirm this is an ext2fs partition?
*/
if (verbose)
sprintf(line, "%s: ext2fs %.6dMB (%d - %d)\n", prefix,
dp->dp_size / 2048, dp->dp_start,
dp->dp_start + dp->dp_size);
else
sprintf(line, "%s: ext2fs\n", prefix);
break;
case 0x00: /* unused partition */
case DOSPTYP_EXT:
return;
case 0x01:
if (verbose)
sprintf(line, "%s: FAT-12 %.6dMB (%d - %d)\n", prefix,
dp->dp_size / 2048, dp->dp_start,
dp->dp_start + dp->dp_size);
else
sprintf(line, "%s: FAT-12\n", prefix);
break;
case 0x04:
case 0x06:
case 0x0e:
if (verbose)
sprintf(line, "%s: FAT-16 %.6dMB (%d - %d)\n", prefix,
dp->dp_size / 2048, dp->dp_start,
dp->dp_start + dp->dp_size);
else
sprintf(line, "%s: FAT-16\n", prefix);
break;
case 0x0b:
case 0x0c:
if (verbose)
sprintf(line, "%s: FAT-32 %.6dMB (%d - %d)\n", prefix,
dp->dp_size / 2048, dp->dp_start,
dp->dp_start + dp->dp_size);
else
sprintf(line, "%s: FAT-32\n", prefix);
break;
default:
if (verbose)
sprintf(line, "%s: Unknown fs: 0x%x %.6dMB (%d - %d)\n",
prefix, dp->dp_typ, dp->dp_size / 2048,
dp->dp_start, dp->dp_start + dp->dp_size);
else
sprintf(line, "%s: Unknown fs: 0x%x\n", prefix,
dp->dp_typ);
}
pager_output(line);
}
/*
* Print out each valid partition in the disklabel of a FreeBSD slice.
* For size calculations, we assume a 512 byte sector size.
*/
static void
bd_printbsdslice(struct open_disk *od, daddr_t offset, char *prefix,
int verbose)
{
char line[80];
char buf[BIOSDISK_SECSIZE];
struct disklabel *lp;
int i;
/* read disklabel */
if (bd_read(od, offset + LABELSECTOR, 1, buf))
return;
lp =(struct disklabel *)(&buf[0]);
if (lp->d_magic != DISKMAGIC) {
sprintf(line, "%s: FFS bad disklabel\n", prefix);
pager_output(line);
return;
}
/* Print partitions */
for (i = 0; i < lp->d_npartitions; i++) {
/*
* For each partition, make sure we know what type of fs it is. If
* not, then skip it. However, since floppies often have bogus
* fstypes, print the 'a' partition on a floppy even if it is marked
* unused.
*/
if ((lp->d_partitions[i].p_fstype == FS_BSDFFS) ||
(lp->d_partitions[i].p_fstype == FS_SWAP) ||
(lp->d_partitions[i].p_fstype == FS_VINUM) ||
((lp->d_partitions[i].p_fstype == FS_UNUSED) &&
(od->od_flags & BD_FLOPPY) && (i == 0))) {
/* Only print out statistics in verbose mode */
if (verbose)
sprintf(line, " %s%c: %s %.6dMB (%d - %d)\n", prefix, 'a' + i,
(lp->d_partitions[i].p_fstype == FS_SWAP) ? "swap" :
(lp->d_partitions[i].p_fstype == FS_VINUM) ? "vinum" :
"FFS",
lp->d_partitions[i].p_size / 2048,
lp->d_partitions[i].p_offset,
lp->d_partitions[i].p_offset + lp->d_partitions[i].p_size);
else
sprintf(line, " %s%c: %s\n", prefix, 'a' + i,
(lp->d_partitions[i].p_fstype == FS_SWAP) ? "swap" :
(lp->d_partitions[i].p_fstype == FS_VINUM) ? "vinum" :
"FFS");
pager_output(line);
}
}
}
/*
* Attempt to open the disk described by (dev) for use by (f).
*
* Note that the philosophy here is "give them exactly what
* they ask for". This is necessary because being too "smart"
* about what the user might want leads to complications.
* (eg. given no slice or partition value, with a disk that is
* sliced - are they after the first BSD slice, or the DOS
* slice before it?)
*/
static int
bd_open(struct open_file *f, ...)
{
va_list ap;
struct i386_devdesc *dev;
struct open_disk *od;
int error;
va_start(ap, f);
dev = va_arg(ap, struct i386_devdesc *);
va_end(ap);
if ((error = bd_opendisk(&od, dev)))
return(error);
/*
* Save our context
*/
((struct i386_devdesc *)(f->f_devdata))->d_kind.biosdisk.data = od;
DEBUG("open_disk %p, partition at 0x%x", od, od->od_boff);
return(0);
}
static int
bd_opendisk(struct open_disk **odp, struct i386_devdesc *dev)
{
struct dos_partition *dptr;
struct disklabel *lp;
struct open_disk *od;
int sector, slice, i;
int error;
char buf[BUFSIZE];
if (dev->d_kind.biosdisk.unit >= nbdinfo) {
DEBUG("attempt to open nonexistent disk");
return(ENXIO);
}
od = (struct open_disk *)malloc(sizeof(struct open_disk));
if (!od) {
DEBUG("no memory");
return (ENOMEM);
}
/* Look up BIOS unit number, intialise open_disk structure */
od->od_dkunit = dev->d_kind.biosdisk.unit;
od->od_unit = bdinfo[od->od_dkunit].bd_unit;
od->od_flags = bdinfo[od->od_dkunit].bd_flags;
od->od_boff = 0;
od->od_nslices = 0;
error = 0;
DEBUG("open '%s', unit 0x%x slice %d partition %c",
i386_fmtdev(dev), dev->d_kind.biosdisk.unit,
dev->d_kind.biosdisk.slice, dev->d_kind.biosdisk.partition + 'a');
/* Get geometry for this open (removable device may have changed) */
if (bd_getgeom(od)) {
DEBUG("can't get geometry");
error = ENXIO;
goto out;
}
/*
* Following calculations attempt to determine the correct value
* for d->od_boff by looking for the slice and partition specified,
* or searching for reasonable defaults.
*/
/*
* Find the slice in the DOS slice table.
*/
if (bd_read(od, 0, 1, buf)) {
DEBUG("error reading MBR");
error = EIO;
goto out;
}
/*
* Check the slice table magic.
*/
if (((u_char)buf[0x1fe] != 0x55) || ((u_char)buf[0x1ff] != 0xaa)) {
/* If a slice number was explicitly supplied, this is an error */
if (dev->d_kind.biosdisk.slice > 0) {
DEBUG("no slice table/MBR (no magic)");
error = ENOENT;
goto out;
}
sector = 0;
goto unsliced; /* may be a floppy */
}
/*
* copy the partition table, then pick up any extended partitions.
*/
bcopy(buf + DOSPARTOFF, &od->od_slicetab,
sizeof(struct dos_partition) * NDOSPART);
od->od_nslices = 4; /* extended slices start here */
for (i = 0; i < NDOSPART; i++)
bd_checkextended(od, i);
od->od_flags |= BD_PARTTABOK;
dptr = &od->od_slicetab[0];
/* Is this a request for the whole disk? */
if (dev->d_kind.biosdisk.slice == -1) {
sector = 0;
goto unsliced;
}
/*
* if a slice number was supplied but not found, this is an error.
*/
if (dev->d_kind.biosdisk.slice > 0) {
slice = dev->d_kind.biosdisk.slice - 1;
if (slice >= od->od_nslices) {
DEBUG("slice %d not found", slice);
error = ENOENT;
goto out;
}
}
/*
* Check for the historically bogus MBR found on true dedicated disks
*/
if ((dptr[3].dp_typ == DOSPTYP_386BSD) &&
(dptr[3].dp_start == 0) &&
(dptr[3].dp_size == 50000)) {
sector = 0;
goto unsliced;
}
/* Try to auto-detect the best slice; this should always give a slice number */
if (dev->d_kind.biosdisk.slice == 0) {
slice = bd_bestslice(od);
if (slice == -1) {
error = ENOENT;
goto out;
}
dev->d_kind.biosdisk.slice = slice;
}
dptr = &od->od_slicetab[0];
/*
* Accept the supplied slice number unequivocally (we may be looking
* at a DOS partition).
*/
dptr += (dev->d_kind.biosdisk.slice - 1); /* we number 1-4, offsets are 0-3 */
sector = dptr->dp_start;
DEBUG("slice entry %d at %d, %d sectors", dev->d_kind.biosdisk.slice - 1, sector, dptr->dp_size);
/*
* If we are looking at a BSD slice, and the partition is < 0, assume the 'a' partition
*/
if ((dptr->dp_typ == DOSPTYP_386BSD) && (dev->d_kind.biosdisk.partition < 0))
dev->d_kind.biosdisk.partition = 0;
unsliced:
/*
* Now we have the slice offset, look for the partition in the disklabel if we have
* a partition to start with.
*
* XXX we might want to check the label checksum.
*/
if (dev->d_kind.biosdisk.partition < 0) {
od->od_boff = sector; /* no partition, must be after the slice */
DEBUG("opening raw slice");
} else {
if (bd_read(od, sector + LABELSECTOR, 1, buf)) {
DEBUG("error reading disklabel");
error = EIO;
goto out;
}
DEBUG("copy %d bytes of label from %p to %p", sizeof(struct disklabel), buf + LABELOFFSET, &od->od_disklabel);
bcopy(buf + LABELOFFSET, &od->od_disklabel, sizeof(struct disklabel));
lp = &od->od_disklabel;
od->od_flags |= BD_LABELOK;
if (lp->d_magic != DISKMAGIC) {
DEBUG("no disklabel");
error = ENOENT;
goto out;
}
if (dev->d_kind.biosdisk.partition >= lp->d_npartitions) {
DEBUG("partition '%c' exceeds partitions in table (a-'%c')",
'a' + dev->d_kind.biosdisk.partition, 'a' + lp->d_npartitions);
error = EPART;
goto out;
}
#ifdef DISK_DEBUG
/* Complain if the partition is unused unless this is a floppy. */
if ((lp->d_partitions[dev->d_kind.biosdisk.partition].p_fstype == FS_UNUSED) &&
!(od->od_flags & BD_FLOPPY))
DEBUG("warning, partition marked as unused");
#endif
od->od_boff = lp->d_partitions[dev->d_kind.biosdisk.partition].p_offset;
}
out:
if (error) {
free(od);
} else {
*odp = od; /* return the open disk */
}
return(error);
}
static void
bd_checkextended(struct open_disk *od, int slicenum)
{
char buf[BIOSDISK_SECSIZE];
struct dos_partition *dp;
u_int base;
int i, start, end;
dp = &od->od_slicetab[slicenum];
start = od->od_nslices;
if (dp->dp_size == 0)
goto done;
if (dp->dp_typ != DOSPTYP_EXT)
goto done;
if (bd_read(od, (daddr_t)dp->dp_start, 1, buf))
goto done;
if (((u_char)buf[0x1fe] != 0x55) || ((u_char)buf[0x1ff] != 0xaa)) {
DEBUG("no magic in extended table");
goto done;
}
base = dp->dp_start;
dp = (struct dos_partition *)(&buf[DOSPARTOFF]);
for (i = 0; i < NDOSPART; i++, dp++) {
if (dp->dp_size == 0)
continue;
if (od->od_nslices == MAX_SLICES)
goto done;
dp->dp_start += base;
bcopy(dp, &od->od_slicetab[od->od_nslices], sizeof(*dp));
od->od_nslices++;
}
end = od->od_nslices;
/*
* now, recursively check the slices we just added
*/
for (i = start; i < end; i++)
bd_checkextended(od, i);
done:
return;
}
/*
* Search for a slice with the following preferences:
*
* 1: Active FreeBSD slice
* 2: Non-active FreeBSD slice
* 3: Active Linux slice
* 4: non-active Linux slice
* 5: Active FAT/FAT32 slice
* 6: non-active FAT/FAT32 slice
*/
#define PREF_RAWDISK 0
#define PREF_FBSD_ACT 1
#define PREF_FBSD 2
#define PREF_LINUX_ACT 3
#define PREF_LINUX 4
#define PREF_DOS_ACT 5
#define PREF_DOS 6
#define PREF_NONE 7
/*
* slicelimit is in the range 0 .. NDOSPART
*/
static int
bd_bestslice(struct open_disk *od)
{
struct dos_partition *dp;
int pref, preflevel;
int i, prefslice;
prefslice = 0;
preflevel = PREF_NONE;
dp = &od->od_slicetab[0];
for (i = 0; i < od->od_nslices; i++, dp++) {
switch (dp->dp_typ) {
case DOSPTYP_386BSD: /* FreeBSD */
pref = dp->dp_flag & 0x80 ? PREF_FBSD_ACT : PREF_FBSD;
break;
case DOSPTYP_LINUX:
pref = dp->dp_flag & 0x80 ? PREF_LINUX_ACT : PREF_LINUX;
break;
case 0x01: /* DOS/Windows */
case 0x04:
case 0x06:
case 0x0b:
case 0x0c:
case 0x0e:
pref = dp->dp_flag & 0x80 ? PREF_DOS_ACT : PREF_DOS;
break;
default:
pref = PREF_NONE;
}
if (pref < preflevel) {
preflevel = pref;
prefslice = i + 1;
}
}
return (prefslice);
}
static int
bd_close(struct open_file *f)
{
struct open_disk *od = (struct open_disk *)(((struct i386_devdesc *)(f->f_devdata))->d_kind.biosdisk.data);
bd_closedisk(od);
return(0);
}
static void
bd_closedisk(struct open_disk *od)
{
DEBUG("open_disk %p", od);
#if 0
/* XXX is this required? (especially if disk already open...) */
if (od->od_flags & BD_FLOPPY)
delay(3000000);
#endif
free(od);
}
static int
bd_strategy(void *devdata, int rw, daddr_t dblk, size_t size, char *buf, size_t *rsize)
{
struct bcache_devdata bcd;
struct open_disk *od = (struct open_disk *)(((struct i386_devdesc *)devdata)->d_kind.biosdisk.data);
bcd.dv_strategy = bd_realstrategy;
bcd.dv_devdata = devdata;
return(bcache_strategy(&bcd, od->od_unit, rw, dblk+od->od_boff, size, buf, rsize));
}
static int
bd_realstrategy(void *devdata, int rw, daddr_t dblk, size_t size, char *buf, size_t *rsize)
{
struct open_disk *od = (struct open_disk *)(((struct i386_devdesc *)devdata)->d_kind.biosdisk.data);
int blks;
#ifdef BD_SUPPORT_FRAGS
char fragbuf[BIOSDISK_SECSIZE];
size_t fragsize;
fragsize = size % BIOSDISK_SECSIZE;
#else
if (size % BIOSDISK_SECSIZE)
panic("bd_strategy: %d bytes I/O not multiple of block size", size);
#endif
DEBUG("open_disk %p", od);
switch(rw){
case F_READ:
blks = size / BIOSDISK_SECSIZE;
DEBUG("read %d from %d to %p", blks, dblk, buf);
if (rsize)
*rsize = 0;
if (blks && bd_read(od, dblk, blks, buf)) {
DEBUG("read error");
return (EIO);
}
#ifdef BD_SUPPORT_FRAGS
DEBUG("bd_strategy: frag read %d from %d+%d to %p",
fragsize, dblk, blks, buf + (blks * BIOSDISK_SECSIZE));
if (fragsize && bd_read(od, dblk + blks, 1, fragsize)) {
DEBUG("frag read error");
return(EIO);
}
bcopy(fragbuf, buf + (blks * BIOSDISK_SECSIZE), fragsize);
#endif
if (rsize)
*rsize = size;
return (0);
break;
case F_WRITE :
blks = size / BIOSDISK_SECSIZE;
DEBUG("write %d from %d to %p", blks, dblk, buf);
if (rsize)
*rsize = 0;
if (blks && bd_write(od, dblk, blks, buf)) {
DEBUG("write error");
return (EIO);
}
#ifdef BD_SUPPORT_FRAGS
if(fragsize) {
DEBUG("Attempted to write a frag");
return (EIO);
}
#endif
if (rsize)
*rsize = size;
return (0);
default:
/* DO NOTHING */
}
return EROFS;
}
/* Max number of sectors to bounce-buffer if the request crosses a 64k boundary */
#define FLOPPY_BOUNCEBUF 18
static int
bd_read(struct open_disk *od, daddr_t dblk, int blks, caddr_t dest)
{
u_int x, bpc, cyl, hd, sec, result, resid, retry, maxfer;
caddr_t p, xp, bbuf, breg;
/* Just in case some idiot actually tries to read -1 blocks... */
if (blks < 0)
return (-1);
bpc = (od->od_sec * od->od_hds); /* blocks per cylinder */
resid = blks;
p = dest;
/* Decide whether we have to bounce */
if ((od->od_unit < 0x80) &&
((VTOP(dest) >> 16) != (VTOP(dest + blks * BIOSDISK_SECSIZE) >> 16))) {
/*
* There is a 64k physical boundary somewhere in the destination buffer, so we have
* to arrange a suitable bounce buffer. Allocate a buffer twice as large as we
* need to. Use the bottom half unless there is a break there, in which case we
* use the top half.
*/
x = min(FLOPPY_BOUNCEBUF, (unsigned)blks);
bbuf = malloc(x * 2 * BIOSDISK_SECSIZE);
if (((u_int32_t)VTOP(bbuf) & 0xffff0000) == ((u_int32_t)VTOP(dest + x * BIOSDISK_SECSIZE) & 0xffff0000)) {
breg = bbuf;
} else {
breg = bbuf + x * BIOSDISK_SECSIZE;
}
maxfer = x; /* limit transfers to bounce region size */
} else {
breg = bbuf = NULL;
maxfer = 0;
}
while (resid > 0) {
x = dblk;
cyl = x / bpc; /* block # / blocks per cylinder */
x %= bpc; /* block offset into cylinder */
hd = x / od->od_sec; /* offset / blocks per track */
sec = x % od->od_sec; /* offset into track */
/* play it safe and don't cross track boundaries (XXX this is probably unnecessary) */
x = min(od->od_sec - sec, resid);
if (maxfer > 0)
x = min(x, maxfer); /* fit bounce buffer */
/* where do we transfer to? */
xp = bbuf == NULL ? p : breg;
/* correct sector number for 1-based BIOS numbering */
sec++;
/* Loop retrying the operation a couple of times. The BIOS may also retry. */
for (retry = 0; retry < 3; retry++) {
/* if retrying, reset the drive */
if (retry > 0) {
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0;
v86.edx = od->od_unit;
v86int();
}
if(cyl > 1023) {
/* use EDD if the disk supports it, otherwise, return error */
if(od->od_flags & BD_MODEEDD1) {
static unsigned short packet[8];
packet[0] = 0x10;
packet[1] = x;
packet[2] = VTOPOFF(xp);
packet[3] = VTOPSEG(xp);
packet[4] = dblk & 0xffff;
packet[5] = dblk >> 16;
packet[6] = 0;
packet[7] = 0;
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0x4200;
v86.edx = od->od_unit;
v86.ds = VTOPSEG(packet);
v86.esi = VTOPOFF(packet);
v86int();
result = (v86.efl & 0x1);
if(result == 0)
break;
} else {
result = 1;
break;
}
} else {
/* Use normal CHS addressing */
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0x200 | x;
v86.ecx = ((cyl & 0xff) << 8) | ((cyl & 0x300) >> 2) | sec;
v86.edx = (hd << 8) | od->od_unit;
v86.es = VTOPSEG(xp);
v86.ebx = VTOPOFF(xp);
v86int();
result = (v86.efl & 0x1);
if (result == 0)
break;
}
}
DEBUG("%d sectors from %d/%d/%d to %p (0x%x) %s", x, cyl, hd, sec - 1, p, VTOP(p), result ? "failed" : "ok");
/* BUG here, cannot use v86 in printf because putchar uses it too */
DEBUG("ax = 0x%04x cx = 0x%04x dx = 0x%04x status 0x%x",
0x200 | x, ((cyl & 0xff) << 8) | ((cyl & 0x300) >> 2) | sec, (hd << 8) | od->od_unit, (v86.eax >> 8) & 0xff);
if (result) {
if (bbuf != NULL)
free(bbuf);
return(-1);
}
if (bbuf != NULL)
bcopy(breg, p, x * BIOSDISK_SECSIZE);
p += (x * BIOSDISK_SECSIZE);
dblk += x;
resid -= x;
}
/* hexdump(dest, (blks * BIOSDISK_SECSIZE)); */
if (bbuf != NULL)
free(bbuf);
return(0);
}
static int
bd_write(struct open_disk *od, daddr_t dblk, int blks, caddr_t dest)
{
u_int x, bpc, cyl, hd, sec, result, resid, retry, maxfer;
caddr_t p, xp, bbuf, breg;
/* Just in case some idiot actually tries to read -1 blocks... */
if (blks < 0)
return (-1);
bpc = (od->od_sec * od->od_hds); /* blocks per cylinder */
resid = blks;
p = dest;
/* Decide whether we have to bounce */
if ((od->od_unit < 0x80) &&
((VTOP(dest) >> 16) != (VTOP(dest + blks * BIOSDISK_SECSIZE) >> 16))) {
/*
* There is a 64k physical boundary somewhere in the destination buffer, so we have
* to arrange a suitable bounce buffer. Allocate a buffer twice as large as we
* need to. Use the bottom half unless there is a break there, in which case we
* use the top half.
*/
x = min(FLOPPY_BOUNCEBUF, (unsigned)blks);
bbuf = malloc(x * 2 * BIOSDISK_SECSIZE);
if (((u_int32_t)VTOP(bbuf) & 0xffff0000) == ((u_int32_t)VTOP(dest + x * BIOSDISK_SECSIZE) & 0xffff0000)) {
breg = bbuf;
} else {
breg = bbuf + x * BIOSDISK_SECSIZE;
}
maxfer = x; /* limit transfers to bounce region size */
} else {
breg = bbuf = NULL;
maxfer = 0;
}
while (resid > 0) {
x = dblk;
cyl = x / bpc; /* block # / blocks per cylinder */
x %= bpc; /* block offset into cylinder */
hd = x / od->od_sec; /* offset / blocks per track */
sec = x % od->od_sec; /* offset into track */
/* play it safe and don't cross track boundaries (XXX this is probably unnecessary) */
x = min(od->od_sec - sec, resid);
if (maxfer > 0)
x = min(x, maxfer); /* fit bounce buffer */
/* where do we transfer to? */
xp = bbuf == NULL ? p : breg;
/* correct sector number for 1-based BIOS numbering */
sec++;
/* Put your Data In, Put your Data out,
Put your Data In, and shake it all about
*/
if (bbuf != NULL)
bcopy(p, breg, x * BIOSDISK_SECSIZE);
p += (x * BIOSDISK_SECSIZE);
dblk += x;
resid -= x;
/* Loop retrying the operation a couple of times. The BIOS may also retry. */
for (retry = 0; retry < 3; retry++) {
/* if retrying, reset the drive */
if (retry > 0) {
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0;
v86.edx = od->od_unit;
v86int();
}
if(cyl > 1023) {
/* use EDD if the disk supports it, otherwise, return error */
if(od->od_flags & BD_MODEEDD1) {
static unsigned short packet[8];
packet[0] = 0x10;
packet[1] = x;
packet[2] = VTOPOFF(xp);
packet[3] = VTOPSEG(xp);
packet[4] = dblk & 0xffff;
packet[5] = dblk >> 16;
packet[6] = 0;
packet[7] = 0;
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
/* Should we Write with verify ?? 0x4302 ? */
v86.eax = 0x4300;
v86.edx = od->od_unit;
v86.ds = VTOPSEG(packet);
v86.esi = VTOPOFF(packet);
v86int();
result = (v86.efl & 0x1);
if(result == 0)
break;
} else {
result = 1;
break;
}
} else {
/* Use normal CHS addressing */
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0x300 | x;
v86.ecx = ((cyl & 0xff) << 8) | ((cyl & 0x300) >> 2) | sec;
v86.edx = (hd << 8) | od->od_unit;
v86.es = VTOPSEG(xp);
v86.ebx = VTOPOFF(xp);
v86int();
result = (v86.efl & 0x1);
if (result == 0)
break;
}
}
DEBUG("%d sectors from %d/%d/%d to %p (0x%x) %s", x, cyl, hd, sec - 1, p, VTOP(p), result ? "failed" : "ok");
/* BUG here, cannot use v86 in printf because putchar uses it too */
DEBUG("ax = 0x%04x cx = 0x%04x dx = 0x%04x status 0x%x",
0x200 | x, ((cyl & 0xff) << 8) | ((cyl & 0x300) >> 2) | sec, (hd << 8) | od->od_unit, (v86.eax >> 8) & 0xff);
if (result) {
if (bbuf != NULL)
free(bbuf);
return(-1);
}
}
/* hexdump(dest, (blks * BIOSDISK_SECSIZE)); */
if (bbuf != NULL)
free(bbuf);
return(0);
}
static int
bd_getgeom(struct open_disk *od)
{
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0x800;
v86.edx = od->od_unit;
v86int();
if ((v86.efl & 0x1) || /* carry set */
((v86.edx & 0xff) <= (unsigned)(od->od_unit & 0x7f))) /* unit # bad */
return(1);
/* convert max cyl # -> # of cylinders */
od->od_cyl = ((v86.ecx & 0xc0) << 2) + ((v86.ecx & 0xff00) >> 8) + 1;
/* convert max head # -> # of heads */
od->od_hds = ((v86.edx & 0xff00) >> 8) + 1;
od->od_sec = v86.ecx & 0x3f;
DEBUG("unit 0x%x geometry %d/%d/%d", od->od_unit, od->od_cyl, od->od_hds, od->od_sec);
return(0);
}
/*
* Return the BIOS geometry of a given "fixed drive" in a format
* suitable for the legacy bootinfo structure. Since the kernel is
* expecting raw int 0x13/0x8 values for N_BIOS_GEOM drives, we
* prefer to get the information directly, rather than rely on being
* able to put it together from information already maintained for
* different purposes and for a probably different number of drives.
*
* For valid drives, the geometry is expected in the format (31..0)
* "000000cc cccccccc hhhhhhhh 00ssssss"; and invalid drives are
* indicated by returning the geometry of a "1.2M" PC-format floppy
* disk. And, incidentally, what is returned is not the geometry as
* such but the highest valid cylinder, head, and sector numbers.
*/
u_int32_t
bd_getbigeom(int bunit)
{
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0x800;
v86.edx = 0x80 + bunit;
v86int();
if (v86.efl & 0x1)
return 0x4f010f;
return ((v86.ecx & 0xc0) << 18) | ((v86.ecx & 0xff00) << 8) |
(v86.edx & 0xff00) | (v86.ecx & 0x3f);
}
/*
* Return a suitable dev_t value for (dev).
*
* In the case where it looks like (dev) is a SCSI disk, we allow the number of
* IDE disks to be specified in $num_ide_disks. There should be a Better Way.
*/
int
bd_getdev(struct i386_devdesc *dev)
{
struct open_disk *od;
int biosdev;
int major;
int rootdev;
char *nip, *cp;
int unitofs = 0, i, unit;
biosdev = bd_unit2bios(dev->d_kind.biosdisk.unit);
DEBUG("unit %d BIOS device %d", dev->d_kind.biosdisk.unit, biosdev);
if (biosdev == -1) /* not a BIOS device */
return(-1);
if (bd_opendisk(&od, dev) != 0) /* oops, not a viable device */
return(-1);
if (biosdev < 0x80) {
/* floppy (or emulated floppy) or ATAPI device */
if (bdinfo[dev->d_kind.biosdisk.unit].bd_type == DT_ATAPI) {
/* is an ATAPI disk */
major = WFDMAJOR;
} else {
/* is a floppy disk */
major = FDMAJOR;
}
} else {
/* harddisk */
if ((od->od_flags & BD_LABELOK) && (od->od_disklabel.d_type == DTYPE_SCSI)) {
/* label OK, disk labelled as SCSI */
major = DAMAJOR;
/* check for unit number correction hint, now deprecated */
if ((nip = getenv("num_ide_disks")) != NULL) {
i = strtol(nip, &cp, 0);
/* check for parse error */
if ((cp != nip) && (*cp == 0))
unitofs = i;
}
} else {
/* assume an IDE disk */
major = WDMAJOR;
}
}
/* default root disk unit number */
unit = (biosdev & 0x7f) - unitofs;
/* XXX a better kludge to set the root disk unit number */
if ((nip = getenv("root_disk_unit")) != NULL) {
i = strtol(nip, &cp, 0);
/* check for parse error */
if ((cp != nip) && (*cp == 0))
unit = i;
}
rootdev = MAKEBOOTDEV(major,
(dev->d_kind.biosdisk.slice + 1) >> 4, /* XXX slices may be wrong here */
(dev->d_kind.biosdisk.slice + 1) & 0xf,
unit,
dev->d_kind.biosdisk.partition);
DEBUG("dev is 0x%x\n", rootdev);
return(rootdev);
}
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