/*- * 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 1.4 1998/09/18 02:02:33 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 "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); } 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; caddr_t p; bpc = (od->od_sec * od->od_hds); /* blocks per cylinder */ resid = blks; p = dest; 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 */ x = min (od->od_sec - sec, resid); /* correct sector number for 1-based BIOS numbering */ sec++; /* 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(p); v86.ebx = VTOPOFF(p); v86int(); result = (v86.efl & 0x1); DEBUG("%d sectors from %d/%d/%d %s", x, cyl, hd, sec - 1, result ? "failed" : "ok"); if (result) return(-1); p += (x * BIOSDISK_SECSIZE); dblk += x; resid -= x; } /* hexdump(dest, (blks * BIOSDISK_SECSIZE)); */ 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); }