/*- * Copyright (c) 1998 Michael Smith * 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 1.17 1998/11/02 23:28:11 msmith Exp $ */ /* * BIOS disk device handling. * * Ideas and algorithms from: * * - NetBSD libi386/biosdisk.c * - FreeBSD biosboot/disk.c * * XXX Todo: add bad144 support. */ #include #include #include #include #include #include #include #include "libi386.h" #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" , __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) struct disklabel od_disklabel; struct dos_partition od_parttab[NDOSPART]; /* XXX needs to grow for extended partitions */ #define BD_LABELOK (1<<3) #define BD_PARTTABOK (1<<4) }; /* * 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_int13probe(struct bdinfo *bd); 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_realstrategy(void *devdata, int flag, daddr_t dblk, size_t size, void *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 }; 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 dos_partition *dptr); /* * 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. * * 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 = unit; bdinfo[nbdinfo].bd_flags = (unit < 0x80) ? BD_FLOPPY : 0; /* XXX add EDD probes */ 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); bdinfo[nbdinfo].bd_unit = unit; nbdinfo++; } } 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) > (bd->bd_unit & 0x7f))) { /* unit # OK */ bd->bd_flags |= BD_MODEINT13; bd->bd_type = v86.ebx & 0xff; return(1); } return(0); } /* * Print information about disks */ static void bd_print(int verbose) { int i; char line[80]; for (i = 0; i < nbdinfo; i++) { sprintf(line, " disk%d: BIOS drive %c:", i, (bdinfo[i].bd_unit < 0x80) ? ('A' + bdinfo[i].bd_unit) : ('C' + bdinfo[i].bd_unit - 0x80)); pager_output(line); /* XXX more detail? */ pager_output("\n"); } } /* * 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; u_char buf[BUFSIZE]; daddr_t pref_slice[4]; 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, buf)) { DEBUG("error reading MBR"); error = EIO; goto out; } /* * Check the slice table magic. */ if ((buf[0x1fe] != 0x55) || (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 */ } bcopy(buf + DOSPARTOFF, &od->od_parttab, sizeof(struct dos_partition) * NDOSPART); dptr = &od->od_parttab[0]; od->od_flags |= BD_PARTTABOK; /* Try to auto-detect the best slice; this should always give a slice number */ if (dev->d_kind.biosdisk.slice < 1) dev->d_kind.biosdisk.slice = bd_bestslice(dptr); switch (dev->d_kind.biosdisk.slice) { case -1: error = ENOENT; goto out; case 0: sector = 0; goto unsliced; default: break; } /* * 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; } /* 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; } out: if (error) { free(od); } else { *odp = od; /* return the open disk */ } return(error); } /* * Search for a slice with the following preferences: * * 1: Active FreeBSD slice * 2: Non-active FreeBSD slice * 3: Active FAT/FAT32 slice * 4: non-active FAT/FAT32 slice */ #define PREF_FBSD_ACT 0 #define PREF_FBSD 1 #define PREF_DOS_ACT 2 #define PREF_DOS 3 #define PREF_NONE 4 static int bd_bestslice(struct dos_partition *dptr) { int i; int preflevel, pref; /* * 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)) return(0); preflevel = PREF_NONE; pref = -1; /* * XXX No support here for 'extended' slices */ for (i = 0; i < NDOSPART; i++) { switch(dptr[i].dp_typ) { case DOSPTYP_386BSD: /* FreeBSD */ if ((dptr[i].dp_flag & 0x80) && (preflevel > PREF_FBSD_ACT)) { pref = i; preflevel = PREF_FBSD_ACT; } else if (preflevel > PREF_FBSD) { pref = i; preflevel = PREF_FBSD; } break; case 0x04: /* DOS/Windows */ case 0x06: case 0x0b: case 0x0c: case 0x0e: case 0x63: if ((dptr[i].dp_flag & 0x80) && (preflevel > PREF_DOS_ACT)) { pref = i; preflevel = PREF_DOS_ACT; } else if (preflevel > PREF_DOS) { pref = i; preflevel = PREF_DOS; } break; } } return(pref + 1); /* slices numbered 1-4 */ } 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, void *buf, size_t *rsize) { struct bcache_devdata bcd; bcd.dv_strategy = bd_realstrategy; bcd.dv_devdata = devdata; return(bcache_strategy(&bcd, rw, dblk, size, buf, rsize)); } static int bd_realstrategy(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", 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"); /* 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_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); } /* * 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; 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 */ if ((nip = getenv("num_ide_disks")) != NULL) { unitofs = strtol(nip, &cp, 0); /* check for parse error */ if ((cp == nip) || (*cp != 0)) unitofs = 0; } } else { /* assume an IDE disk */ major = WDMAJOR; } } rootdev = MAKEBOOTDEV(major, (dev->d_kind.biosdisk.slice + 1) >> 4, /* XXX slices may be wrong here */ (dev->d_kind.biosdisk.slice + 1) & 0xf, (biosdev & 0x7f) - unitofs, /* allow for #wd compenstation in da case */ dev->d_kind.biosdisk.partition); DEBUG("dev is 0x%x\n", rootdev); return(rootdev); } /* * Fix (dev) so that it refers to the 'real' disk/slice/partition that it implies. */ int bd_fixupdev(struct i386_devdesc *dev) { struct open_disk *od; /* * Open the disk. This will fix up the slice and partition fields. */ if (bd_opendisk(&od, dev) != 0) return(ENOENT); bd_closedisk(od); }