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3cae2e80aa
freebsd-dev/sys/boot/i386/libi386/biosdisk.c
Peter Wemm 3cae2e80aa Precedence bug (?) causing probe problems.
1998-09-28 20:07:39 +00:00

524 lines
14 KiB
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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.
*
* $Id: biosdisk.c,v 1.6 1998/09/26 01:30:20 msmith Exp $
*/
/*
* BIOS disk device handling.
*
* Ideas and algorithms from:
*
* - NetBSD libi386/biosdisk.c
* - FreeBSD biosboot/disk.c
*
* XXX Todo: add bad144 support.
*/
#include <stand.h>
#include <sys/disklabel.h>
#include <sys/diskslice.h>
#include <bootstrap.h>
#include <btxv86.h>
#include "libi386.h"
#define BIOSDISK_SECSIZE 512
#define BUFSIZE (1 * BIOSDISK_SECSIZE)
#define MAXBDDEV MAXDEV
#ifdef DISK_DEBUG
# define DEBUG(fmt, args...) printf("%s: " fmt "\n" , __FUNCTION__ , ## 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_MODEMASK 0x3
#define BD_MODEINT13 0x0
#define BD_MODEEDD1 0x1
#define BD_MODEEDD3 0x2
#define BD_FLOPPY (1<<2)
u_char od_buf[BUFSIZE]; /* transfer buffer (do we want/need this?) */
};
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_edd3probe(int unit);
static int bd_edd1probe(int unit);
static int bd_int13probe(int unit);
static int bd_init(void);
static int bd_strategy(void *devdata, int flag, daddr_t dblk, size_t size, void *buf, size_t *rsize);
static int bd_open(struct open_file *f, void *vdev);
static int bd_close(struct open_file *f);
struct devsw biosdisk = {
"disk",
DEVT_DISK,
bd_init,
bd_strategy,
bd_open,
bd_close,
noioctl
};
/*
* List of BIOS devices, translation from disk unit number to
* BIOS unit number.
*/
static struct
{
int bd_unit; /* BIOS unit number */
int bd_flags;
} bdinfo [MAXBDDEV];
static int nbdinfo = 0;
/*
* Quiz the BIOS for disk devices, save a little info about them.
*
* XXX should we be consulting the BIOS equipment list, specifically
* the value at 0x475?
*/
static int
bd_init(void)
{
int base, unit;
/* sequence 0, 0x80 */
for (base = 0; base <= 0x80; base += 0x80) {
for (unit = base; (nbdinfo < MAXBDDEV); unit++) {
bdinfo[nbdinfo].bd_unit = -1;
bdinfo[nbdinfo].bd_flags = (unit < 0x80) ? BD_FLOPPY : 0;
if (bd_edd3probe(unit)) {
bdinfo[nbdinfo].bd_flags |= BD_MODEEDD3;
} else if (bd_edd1probe(unit)) {
bdinfo[nbdinfo].bd_flags |= BD_MODEEDD1;
} else if (bd_int13probe(unit)) {
bdinfo[nbdinfo].bd_flags |= BD_MODEINT13;
} else {
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);
bdinfo[nbdinfo].bd_unit = unit;
nbdinfo++;
}
}
return(0);
}
/*
* Try to detect a device supported by an Enhanced Disk Drive 3.0-compliant BIOS
*/
static int
bd_edd3probe(int unit)
{
return(0); /* XXX not implemented yet */
}
/*
* Try to detect a device supported by an Enhanced Disk Drive 1.1-compliant BIOS
*/
static int
bd_edd1probe(int unit)
{
return(0); /* XXX not implemented yet */
}
/*
* Try to detect a device supported by the legacy int13 BIOS
*/
static int
bd_int13probe(int unit)
{
v86.ctl = V86_FLAGS;
v86.addr = 0x13;
v86.eax = 0x800;
v86.edx = unit;
v86int();
if (!(v86.efl & 0x1) && /* carry clear */
((v86.edx & 0xff) > (unit & 0x7f))) /* unit # OK */
return(1);
return(0);
}
/*
* 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, void *vdev)
{
struct i386_devdesc *dev = (struct i386_devdesc *)vdev;
struct dos_partition *dptr;
struct open_disk *od;
struct disklabel *lp;
int sector, slice, i;
int error;
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;
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, od->od_buf)) {
DEBUG("error reading MBR");
error = EIO;
goto out;
}
/*
* Check the slice table magic.
*/
if ((od->od_buf[0x1fe] != 0xff) || (od->od_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 */
}
dptr = (struct dos_partition *) & od->od_buf[DOSPARTOFF];
/*
* XXX No support here for 'extended' slices
*/
if (dev->d_kind.biosdisk.slice <= 0) {
/*
* Search for the first FreeBSD slice; this also works on "unsliced"
* disks, as they contain a "historically bogus" MBR.
*/
for (i = 0; i < NDOSPART; i++, dptr++)
if (dptr->dp_typ == DOSPTYP_386BSD) {
sector = dptr->dp_start;
break;
}
/* Did we find something? */
if (sector == -1) {
error = ENOENT;
goto out;
}
} else {
/*
* Accept the supplied slice number unequivocally (we may be looking
* for a DOS partition) if we can handle it.
*/
if ((dev->d_kind.biosdisk.slice > NDOSPART) || (dev->d_kind.biosdisk.slice < 1)) {
error = ENOENT;
goto out;
}
dptr += (dev->d_kind.biosdisk.slice - 1);
sector = dptr->dp_start;
}
unsliced:
/*
* Now we have the slice, 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, od->od_buf)) {
DEBUG("error reading disklabel");
error = EIO;
goto out;
}
lp = (struct disklabel *) (od->od_buf + LABELOFFSET);
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;
}
/* Complain if the partition type is wrong */
if ((lp->d_partitions[dev->d_kind.biosdisk.partition].p_fstype == FS_UNUSED) &&
!(od->od_flags & BD_FLOPPY)) /* Floppies often have bogus fstype */
DEBUG("warning, partition marked as unused");
od->od_boff = lp->d_partitions[dev->d_kind.biosdisk.partition].p_offset;
}
/*
* 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);
out:
if (error)
free(od);
return(error);
}
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);
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);
return(0);
}
static int
bd_strategy(void *devdata, int rw, daddr_t dblk, size_t size, void *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);
if (rw != F_READ)
return(EROFS);
blks = size / BIOSDISK_SECSIZE;
DEBUG("read %d from %d+%d to %p", blks, od->od_boff, dblk, buf);
if (rsize)
*rsize = 0;
if (blks && bd_read(od, dblk + od->od_boff, blks, buf)) {
DEBUG("read error");
return (EIO);
}
#ifdef BD_SUPPORT_FRAGS
DEBUG("bd_strategy: frag read %d from %d+%d+d to %p\n",
fragsize, od->od_boff, dblk, blks, buf + (blks * BIOSDISK_SECSIZE));
if (fragsize && bd_read(od, dblk + od->od_boff + blks, 1, fragsize)) {
DEBUG("frag read error");
return(EIO);
}
bcopy(fragbuf, buf + (blks * BIOSDISK_SECSIZE), fragsize);
#endif
if (rsize)
*rsize = size;
return (0);
}
/* 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)
{
int x, bpc, cyl, hd, sec, result, resid, cnt, retry, maxfer;
caddr_t p, xp, bbuf, breg;
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, 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 {
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();
}
/* build request XXX support EDD requests too */
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");
DEBUG("ax = 0x%04x cx = 0x%04x dx = 0x%04x status 0x%x\n",
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_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) <= (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);
}
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