1 /*- 2 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org> 3 * Copyright (c) 2012 Andrey V. Elsukov <ae@FreeBSD.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 /* 32 * BIOS disk device handling. 33 * 34 * Ideas and algorithms from: 35 * 36 * - NetBSD libi386/biosdisk.c 37 * - FreeBSD biosboot/disk.c 38 * 39 */ 40 41 #include <sys/disk.h> 42 #include <stand.h> 43 #include <machine/bootinfo.h> 44 #include <stdarg.h> 45 46 #include <bootstrap.h> 47 #include <btxv86.h> 48 #include <edd.h> 49 #include "disk.h" 50 #include "libi386.h" 51 52 CTASSERT(sizeof(struct i386_devdesc) >= sizeof(struct disk_devdesc)); 53 54 #define BIOS_NUMDRIVES 0x475 55 #define BIOSDISK_SECSIZE 512 56 #define BUFSIZE (1 * BIOSDISK_SECSIZE) 57 58 #define DT_ATAPI 0x10 /* disk type for ATAPI floppies */ 59 #define WDMAJOR 0 /* major numbers for devices we frontend for */ 60 #define WFDMAJOR 1 61 #define FDMAJOR 2 62 #define DAMAJOR 4 63 64 #ifdef DISK_DEBUG 65 # define DEBUG(fmt, args...) printf("%s: " fmt "\n" , __func__ , ## args) 66 #else 67 # define DEBUG(fmt, args...) 68 #endif 69 70 /* 71 * List of BIOS devices, translation from disk unit number to 72 * BIOS unit number. 73 */ 74 static struct bdinfo 75 { 76 int bd_unit; /* BIOS unit number */ 77 int bd_cyl; /* BIOS geometry */ 78 int bd_hds; 79 int bd_sec; 80 int bd_flags; 81 #define BD_MODEINT13 0x0000 82 #define BD_MODEEDD1 0x0001 83 #define BD_MODEEDD3 0x0002 84 #define BD_MODEMASK 0x0003 85 #define BD_FLOPPY 0x0004 86 int bd_type; /* BIOS 'drive type' (floppy only) */ 87 uint16_t bd_sectorsize; /* Sector size */ 88 uint64_t bd_sectors; /* Disk size */ 89 int bd_open; /* reference counter */ 90 void *bd_bcache; /* buffer cache data */ 91 } bdinfo [MAXBDDEV]; 92 static int nbdinfo = 0; 93 94 #define BD(dev) (bdinfo[(dev)->d_unit]) 95 96 static int bd_read(struct disk_devdesc *dev, daddr_t dblk, int blks, 97 caddr_t dest); 98 static int bd_write(struct disk_devdesc *dev, daddr_t dblk, int blks, 99 caddr_t dest); 100 static int bd_int13probe(struct bdinfo *bd); 101 102 static int bd_init(void); 103 static int bd_strategy(void *devdata, int flag, daddr_t dblk, size_t offset, 104 size_t size, char *buf, size_t *rsize); 105 static int bd_realstrategy(void *devdata, int flag, daddr_t dblk, size_t offset, 106 size_t size, char *buf, size_t *rsize); 107 static int bd_open(struct open_file *f, ...); 108 static int bd_close(struct open_file *f); 109 static int bd_ioctl(struct open_file *f, u_long cmd, void *data); 110 static int bd_print(int verbose); 111 static void bd_cleanup(void); 112 113 struct devsw biosdisk = { 114 "disk", 115 DEVT_DISK, 116 bd_init, 117 bd_strategy, 118 bd_open, 119 bd_close, 120 bd_ioctl, 121 bd_print, 122 bd_cleanup 123 }; 124 125 /* 126 * Translate between BIOS device numbers and our private unit numbers. 127 */ 128 int 129 bd_bios2unit(int biosdev) 130 { 131 int i; 132 133 DEBUG("looking for bios device 0x%x", biosdev); 134 for (i = 0; i < nbdinfo; i++) { 135 DEBUG("bd unit %d is BIOS device 0x%x", i, bdinfo[i].bd_unit); 136 if (bdinfo[i].bd_unit == biosdev) 137 return (i); 138 } 139 return (-1); 140 } 141 142 int 143 bd_unit2bios(int unit) 144 { 145 146 if ((unit >= 0) && (unit < nbdinfo)) 147 return (bdinfo[unit].bd_unit); 148 return (-1); 149 } 150 151 /* 152 * Quiz the BIOS for disk devices, save a little info about them. 153 */ 154 static int 155 bd_init(void) 156 { 157 int base, unit, nfd = 0; 158 159 /* sequence 0, 0x80 */ 160 for (base = 0; base <= 0x80; base += 0x80) { 161 for (unit = base; (nbdinfo < MAXBDDEV); unit++) { 162 #ifndef VIRTUALBOX 163 /* 164 * Check the BIOS equipment list for number 165 * of fixed disks. 166 */ 167 if(base == 0x80 && 168 (nfd >= *(unsigned char *)PTOV(BIOS_NUMDRIVES))) 169 break; 170 #endif 171 bdinfo[nbdinfo].bd_open = 0; 172 bdinfo[nbdinfo].bd_bcache = NULL; 173 bdinfo[nbdinfo].bd_unit = unit; 174 bdinfo[nbdinfo].bd_flags = unit < 0x80 ? BD_FLOPPY: 0; 175 if (!bd_int13probe(&bdinfo[nbdinfo])) 176 break; 177 178 #ifndef BOOT2 179 /* XXX we need "disk aliases" to make this simpler */ 180 printf("BIOS drive %c: is disk%d\n", (unit < 0x80) ? 181 ('A' + unit): ('C' + unit - 0x80), nbdinfo); 182 #endif 183 nbdinfo++; 184 if (base == 0x80) 185 nfd++; 186 } 187 } 188 bcache_add_dev(nbdinfo); 189 return(0); 190 } 191 192 static void 193 bd_cleanup(void) 194 { 195 196 disk_cleanup(&biosdisk); 197 } 198 199 /* 200 * Try to detect a device supported by the legacy int13 BIOS 201 */ 202 static int 203 bd_int13probe(struct bdinfo *bd) 204 { 205 struct edd_params params; 206 int ret = 1; /* assume success */ 207 208 v86.ctl = V86_FLAGS; 209 v86.addr = 0x13; 210 v86.eax = 0x800; 211 v86.edx = bd->bd_unit; 212 v86int(); 213 214 /* Don't error out if we get bad sector number, try EDD as well */ 215 if (V86_CY(v86.efl) || /* carry set */ 216 (v86.edx & 0xff) <= (unsigned)(bd->bd_unit & 0x7f)) /* unit # bad */ 217 return (0); /* skip device */ 218 219 if ((v86.ecx & 0x3f) == 0) /* absurd sector number */ 220 ret = 0; /* set error */ 221 222 /* Convert max cyl # -> # of cylinders */ 223 bd->bd_cyl = ((v86.ecx & 0xc0) << 2) + ((v86.ecx & 0xff00) >> 8) + 1; 224 /* Convert max head # -> # of heads */ 225 bd->bd_hds = ((v86.edx & 0xff00) >> 8) + 1; 226 bd->bd_sec = v86.ecx & 0x3f; 227 bd->bd_type = v86.ebx & 0xff; 228 bd->bd_flags |= BD_MODEINT13; 229 230 /* Calculate sectors count from the geometry */ 231 bd->bd_sectors = bd->bd_cyl * bd->bd_hds * bd->bd_sec; 232 bd->bd_sectorsize = BIOSDISK_SECSIZE; 233 DEBUG("unit 0x%x geometry %d/%d/%d", bd->bd_unit, bd->bd_cyl, 234 bd->bd_hds, bd->bd_sec); 235 236 /* Determine if we can use EDD with this device. */ 237 v86.ctl = V86_FLAGS; 238 v86.addr = 0x13; 239 v86.eax = 0x4100; 240 v86.edx = bd->bd_unit; 241 v86.ebx = 0x55aa; 242 v86int(); 243 if (V86_CY(v86.efl) || /* carry set */ 244 (v86.ebx & 0xffff) != 0xaa55 || /* signature */ 245 (v86.ecx & EDD_INTERFACE_FIXED_DISK) == 0) 246 return (ret); /* return code from int13 AH=08 */ 247 248 /* EDD supported */ 249 bd->bd_flags |= BD_MODEEDD1; 250 if ((v86.eax & 0xff00) >= 0x3000) 251 bd->bd_flags |= BD_MODEEDD3; 252 /* Get disk params */ 253 params.len = sizeof(struct edd_params); 254 v86.ctl = V86_FLAGS; 255 v86.addr = 0x13; 256 v86.eax = 0x4800; 257 v86.edx = bd->bd_unit; 258 v86.ds = VTOPSEG(¶ms); 259 v86.esi = VTOPOFF(¶ms); 260 v86int(); 261 if (!V86_CY(v86.efl)) { 262 uint64_t total; 263 264 if (params.sectors != 0) 265 bd->bd_sectors = params.sectors; 266 267 total = (uint64_t)params.cylinders * 268 params.heads * params.sectors_per_track; 269 if (bd->bd_sectors < total) 270 bd->bd_sectors = total; 271 272 bd->bd_sectorsize = params.sector_size; 273 ret = 1; 274 } 275 DEBUG("unit 0x%x flags %x, sectors %llu, sectorsize %u", 276 bd->bd_unit, bd->bd_flags, bd->bd_sectors, bd->bd_sectorsize); 277 return (ret); 278 } 279 280 /* 281 * Print information about disks 282 */ 283 static int 284 bd_print(int verbose) 285 { 286 static char line[80]; 287 struct disk_devdesc dev; 288 int i, ret = 0; 289 290 for (i = 0; i < nbdinfo; i++) { 291 sprintf(line, " disk%d: BIOS drive %c:\n", i, 292 (bdinfo[i].bd_unit < 0x80) ? ('A' + bdinfo[i].bd_unit): 293 ('C' + bdinfo[i].bd_unit - 0x80)); 294 ret = pager_output(line); 295 if (ret != 0) 296 return (ret); 297 298 dev.d_dev = &biosdisk; 299 dev.d_unit = i; 300 dev.d_slice = -1; 301 dev.d_partition = -1; 302 if (disk_open(&dev, 303 bdinfo[i].bd_sectorsize * bdinfo[i].bd_sectors, 304 bdinfo[i].bd_sectorsize, 305 (bdinfo[i].bd_flags & BD_FLOPPY) ? 306 DISK_F_NOCACHE: 0) == 0) { 307 sprintf(line, " disk%d", i); 308 ret = disk_print(&dev, line, verbose); 309 disk_close(&dev); 310 if (ret != 0) 311 return (ret); 312 } 313 } 314 return (ret); 315 } 316 317 /* 318 * Attempt to open the disk described by (dev) for use by (f). 319 * 320 * Note that the philosophy here is "give them exactly what 321 * they ask for". This is necessary because being too "smart" 322 * about what the user might want leads to complications. 323 * (eg. given no slice or partition value, with a disk that is 324 * sliced - are they after the first BSD slice, or the DOS 325 * slice before it?) 326 */ 327 static int 328 bd_open(struct open_file *f, ...) 329 { 330 struct disk_devdesc *dev; 331 va_list ap; 332 333 va_start(ap, f); 334 dev = va_arg(ap, struct disk_devdesc *); 335 va_end(ap); 336 337 if (dev->d_unit < 0 || dev->d_unit >= nbdinfo) 338 return (EIO); 339 BD(dev).bd_open++; 340 if (BD(dev).bd_bcache == NULL) 341 BD(dev).bd_bcache = bcache_allocate(); 342 return (disk_open(dev, BD(dev).bd_sectors * BD(dev).bd_sectorsize, 343 BD(dev).bd_sectorsize, (BD(dev).bd_flags & BD_FLOPPY) ? 344 DISK_F_NOCACHE: 0)); 345 } 346 347 static int 348 bd_close(struct open_file *f) 349 { 350 struct disk_devdesc *dev; 351 352 dev = (struct disk_devdesc *)f->f_devdata; 353 BD(dev).bd_open--; 354 if (BD(dev).bd_open == 0) { 355 bcache_free(BD(dev).bd_bcache); 356 BD(dev).bd_bcache = NULL; 357 } 358 return (disk_close(dev)); 359 } 360 361 static int 362 bd_ioctl(struct open_file *f, u_long cmd, void *data) 363 { 364 struct disk_devdesc *dev; 365 366 dev = (struct disk_devdesc *)f->f_devdata; 367 switch (cmd) { 368 case DIOCGSECTORSIZE: 369 *(u_int *)data = BD(dev).bd_sectorsize; 370 break; 371 case DIOCGMEDIASIZE: 372 *(off_t *)data = BD(dev).bd_sectors * BD(dev).bd_sectorsize; 373 break; 374 default: 375 return (ENOTTY); 376 } 377 return (0); 378 } 379 380 static int 381 bd_strategy(void *devdata, int rw, daddr_t dblk, size_t offset, size_t size, 382 char *buf, size_t *rsize) 383 { 384 struct bcache_devdata bcd; 385 struct disk_devdesc *dev; 386 387 dev = (struct disk_devdesc *)devdata; 388 bcd.dv_strategy = bd_realstrategy; 389 bcd.dv_devdata = devdata; 390 bcd.dv_cache = BD(dev).bd_bcache; 391 392 return (bcache_strategy(&bcd, rw, dblk + dev->d_offset, offset, size, 393 buf, rsize)); 394 } 395 396 static int 397 bd_realstrategy(void *devdata, int rw, daddr_t dblk, size_t offset, size_t size, 398 char *buf, size_t *rsize) 399 { 400 struct disk_devdesc *dev = (struct disk_devdesc *)devdata; 401 int blks, remaining; 402 #ifdef BD_SUPPORT_FRAGS /* XXX: sector size */ 403 char fragbuf[BIOSDISK_SECSIZE]; 404 size_t fragsize; 405 406 fragsize = size % BIOSDISK_SECSIZE; 407 #else 408 if (size % BD(dev).bd_sectorsize) 409 panic("bd_strategy: %d bytes I/O not multiple of block size", size); 410 #endif 411 412 DEBUG("open_disk %p", dev); 413 blks = size / BD(dev).bd_sectorsize; 414 if (rsize) 415 *rsize = 0; 416 417 /* 418 * Perform partial read to prevent read-ahead crossing 419 * the end of disk - or any 32 bit aliases of the end. 420 * Signed arithmetic is used to handle wrap-around cases 421 * like we do for TCP sequence numbers. 422 */ 423 remaining = (int)(BD(dev).bd_sectors - dblk); /* truncate */ 424 if (remaining > 0 && remaining < blks) { 425 blks = remaining; 426 size = blks * BD(dev).bd_sectorsize; 427 DEBUG("short read %d", blks); 428 } 429 430 switch(rw){ 431 case F_READ: 432 DEBUG("read %d from %lld to %p", blks, dblk, buf); 433 434 if (blks && bd_read(dev, dblk, blks, buf)) { 435 DEBUG("read error"); 436 return (EIO); 437 } 438 #ifdef BD_SUPPORT_FRAGS /* XXX: sector size */ 439 DEBUG("bd_strategy: frag read %d from %d+%d to %p", 440 fragsize, dblk, blks, buf + (blks * BIOSDISK_SECSIZE)); 441 if (fragsize && bd_read(od, dblk + blks, 1, fragsize)) { 442 DEBUG("frag read error"); 443 return(EIO); 444 } 445 bcopy(fragbuf, buf + (blks * BIOSDISK_SECSIZE), fragsize); 446 #endif 447 break; 448 case F_WRITE : 449 DEBUG("write %d from %d to %p", blks, dblk, buf); 450 451 if (blks && bd_write(dev, dblk, blks, buf)) { 452 DEBUG("write error"); 453 return (EIO); 454 } 455 #ifdef BD_SUPPORT_FRAGS 456 if(fragsize) { 457 DEBUG("Attempted to write a frag"); 458 return (EIO); 459 } 460 #endif 461 break; 462 default: 463 /* DO NOTHING */ 464 return (EROFS); 465 } 466 467 if (rsize) 468 *rsize = size; 469 return (0); 470 } 471 472 /* Max number of sectors to bounce-buffer if the request crosses a 64k boundary */ 473 #define FLOPPY_BOUNCEBUF 18 474 475 static int 476 bd_edd_io(struct disk_devdesc *dev, daddr_t dblk, int blks, caddr_t dest, 477 int dowrite) 478 { 479 static struct edd_packet packet; 480 481 packet.len = sizeof(struct edd_packet); 482 packet.count = blks; 483 packet.off = VTOPOFF(dest); 484 packet.seg = VTOPSEG(dest); 485 packet.lba = dblk; 486 v86.ctl = V86_FLAGS; 487 v86.addr = 0x13; 488 if (dowrite) 489 /* Should we Write with verify ?? 0x4302 ? */ 490 v86.eax = 0x4300; 491 else 492 v86.eax = 0x4200; 493 v86.edx = BD(dev).bd_unit; 494 v86.ds = VTOPSEG(&packet); 495 v86.esi = VTOPOFF(&packet); 496 v86int(); 497 return (V86_CY(v86.efl)); 498 } 499 500 static int 501 bd_chs_io(struct disk_devdesc *dev, daddr_t dblk, int blks, caddr_t dest, 502 int dowrite) 503 { 504 u_int x, bpc, cyl, hd, sec; 505 506 bpc = BD(dev).bd_sec * BD(dev).bd_hds; /* blocks per cylinder */ 507 x = dblk; 508 cyl = x / bpc; /* block # / blocks per cylinder */ 509 x %= bpc; /* block offset into cylinder */ 510 hd = x / BD(dev).bd_sec; /* offset / blocks per track */ 511 sec = x % BD(dev).bd_sec; /* offset into track */ 512 513 /* correct sector number for 1-based BIOS numbering */ 514 sec++; 515 516 if (cyl > 1023) 517 /* CHS doesn't support cylinders > 1023. */ 518 return (1); 519 520 v86.ctl = V86_FLAGS; 521 v86.addr = 0x13; 522 if (dowrite) 523 v86.eax = 0x300 | blks; 524 else 525 v86.eax = 0x200 | blks; 526 v86.ecx = ((cyl & 0xff) << 8) | ((cyl & 0x300) >> 2) | sec; 527 v86.edx = (hd << 8) | BD(dev).bd_unit; 528 v86.es = VTOPSEG(dest); 529 v86.ebx = VTOPOFF(dest); 530 v86int(); 531 return (V86_CY(v86.efl)); 532 } 533 534 static int 535 bd_io(struct disk_devdesc *dev, daddr_t dblk, int blks, caddr_t dest, int dowrite) 536 { 537 u_int x, sec, result, resid, retry, maxfer; 538 caddr_t p, xp, bbuf, breg; 539 540 /* Just in case some idiot actually tries to read/write -1 blocks... */ 541 if (blks < 0) 542 return (-1); 543 544 resid = blks; 545 p = dest; 546 547 /* Decide whether we have to bounce */ 548 if (VTOP(dest) >> 20 != 0 || (BD(dev).bd_unit < 0x80 && 549 (VTOP(dest) >> 16) != (VTOP(dest + 550 blks * BD(dev).bd_sectorsize) >> 16))) { 551 552 /* 553 * There is a 64k physical boundary somewhere in the 554 * destination buffer, or the destination buffer is above 555 * first 1MB of physical memory so we have to arrange a 556 * suitable bounce buffer. Allocate a buffer twice as large 557 * as we need to. Use the bottom half unless there is a break 558 * there, in which case we use the top half. 559 */ 560 x = min(FLOPPY_BOUNCEBUF, (unsigned)blks); 561 bbuf = alloca(x * 2 * BD(dev).bd_sectorsize); 562 if (((u_int32_t)VTOP(bbuf) & 0xffff0000) == 563 ((u_int32_t)VTOP(bbuf + x * BD(dev).bd_sectorsize) & 0xffff0000)) { 564 breg = bbuf; 565 } else { 566 breg = bbuf + x * BD(dev).bd_sectorsize; 567 } 568 maxfer = x; /* limit transfers to bounce region size */ 569 } else { 570 breg = bbuf = NULL; 571 maxfer = 0; 572 } 573 574 while (resid > 0) { 575 /* 576 * Play it safe and don't cross track boundaries. 577 * (XXX this is probably unnecessary) 578 */ 579 sec = dblk % BD(dev).bd_sec; /* offset into track */ 580 x = min(BD(dev).bd_sec - sec, resid); 581 if (maxfer > 0) 582 x = min(x, maxfer); /* fit bounce buffer */ 583 584 /* where do we transfer to? */ 585 xp = bbuf == NULL ? p : breg; 586 587 /* 588 * Put your Data In, Put your Data out, 589 * Put your Data In, and shake it all about 590 */ 591 if (dowrite && bbuf != NULL) 592 bcopy(p, breg, x * BD(dev).bd_sectorsize); 593 594 /* 595 * Loop retrying the operation a couple of times. The BIOS 596 * may also retry. 597 */ 598 for (retry = 0; retry < 3; retry++) { 599 /* if retrying, reset the drive */ 600 if (retry > 0) { 601 v86.ctl = V86_FLAGS; 602 v86.addr = 0x13; 603 v86.eax = 0; 604 v86.edx = BD(dev).bd_unit; 605 v86int(); 606 } 607 608 if (BD(dev).bd_flags & BD_MODEEDD1) 609 result = bd_edd_io(dev, dblk, x, xp, dowrite); 610 else 611 result = bd_chs_io(dev, dblk, x, xp, dowrite); 612 if (result == 0) 613 break; 614 } 615 616 if (dowrite) 617 DEBUG("Write %d sector(s) from %p (0x%x) to %lld %s", x, 618 p, VTOP(p), dblk, result ? "failed" : "ok"); 619 else 620 DEBUG("Read %d sector(s) from %lld to %p (0x%x) %s", x, 621 dblk, p, VTOP(p), result ? "failed" : "ok"); 622 if (result) { 623 return(-1); 624 } 625 if (!dowrite && bbuf != NULL) 626 bcopy(breg, p, x * BD(dev).bd_sectorsize); 627 p += (x * BD(dev).bd_sectorsize); 628 dblk += x; 629 resid -= x; 630 } 631 632 /* hexdump(dest, (blks * BD(dev).bd_sectorsize)); */ 633 return(0); 634 } 635 636 static int 637 bd_read(struct disk_devdesc *dev, daddr_t dblk, int blks, caddr_t dest) 638 { 639 640 return (bd_io(dev, dblk, blks, dest, 0)); 641 } 642 643 static int 644 bd_write(struct disk_devdesc *dev, daddr_t dblk, int blks, caddr_t dest) 645 { 646 647 return (bd_io(dev, dblk, blks, dest, 1)); 648 } 649 650 /* 651 * Return the BIOS geometry of a given "fixed drive" in a format 652 * suitable for the legacy bootinfo structure. Since the kernel is 653 * expecting raw int 0x13/0x8 values for N_BIOS_GEOM drives, we 654 * prefer to get the information directly, rather than rely on being 655 * able to put it together from information already maintained for 656 * different purposes and for a probably different number of drives. 657 * 658 * For valid drives, the geometry is expected in the format (31..0) 659 * "000000cc cccccccc hhhhhhhh 00ssssss"; and invalid drives are 660 * indicated by returning the geometry of a "1.2M" PC-format floppy 661 * disk. And, incidentally, what is returned is not the geometry as 662 * such but the highest valid cylinder, head, and sector numbers. 663 */ 664 u_int32_t 665 bd_getbigeom(int bunit) 666 { 667 668 v86.ctl = V86_FLAGS; 669 v86.addr = 0x13; 670 v86.eax = 0x800; 671 v86.edx = 0x80 + bunit; 672 v86int(); 673 if (V86_CY(v86.efl)) 674 return 0x4f010f; 675 return ((v86.ecx & 0xc0) << 18) | ((v86.ecx & 0xff00) << 8) | 676 (v86.edx & 0xff00) | (v86.ecx & 0x3f); 677 } 678 679 /* 680 * Return a suitable dev_t value for (dev). 681 * 682 * In the case where it looks like (dev) is a SCSI disk, we allow the number of 683 * IDE disks to be specified in $num_ide_disks. There should be a Better Way. 684 */ 685 int 686 bd_getdev(struct i386_devdesc *d) 687 { 688 struct disk_devdesc *dev; 689 int biosdev; 690 int major; 691 int rootdev; 692 char *nip, *cp; 693 int i, unit; 694 695 dev = (struct disk_devdesc *)d; 696 biosdev = bd_unit2bios(dev->d_unit); 697 DEBUG("unit %d BIOS device %d", dev->d_unit, biosdev); 698 if (biosdev == -1) /* not a BIOS device */ 699 return(-1); 700 if (disk_open(dev, BD(dev).bd_sectors * BD(dev).bd_sectorsize, 701 BD(dev).bd_sectorsize,(BD(dev).bd_flags & BD_FLOPPY) ? 702 DISK_F_NOCACHE: 0) != 0) /* oops, not a viable device */ 703 return (-1); 704 else 705 disk_close(dev); 706 707 if (biosdev < 0x80) { 708 /* floppy (or emulated floppy) or ATAPI device */ 709 if (bdinfo[dev->d_unit].bd_type == DT_ATAPI) { 710 /* is an ATAPI disk */ 711 major = WFDMAJOR; 712 } else { 713 /* is a floppy disk */ 714 major = FDMAJOR; 715 } 716 } else { 717 /* assume an IDE disk */ 718 major = WDMAJOR; 719 } 720 /* default root disk unit number */ 721 unit = biosdev & 0x7f; 722 723 /* XXX a better kludge to set the root disk unit number */ 724 if ((nip = getenv("root_disk_unit")) != NULL) { 725 i = strtol(nip, &cp, 0); 726 /* check for parse error */ 727 if ((cp != nip) && (*cp == 0)) 728 unit = i; 729 } 730 731 rootdev = MAKEBOOTDEV(major, dev->d_slice + 1, unit, dev->d_partition); 732 DEBUG("dev is 0x%x\n", rootdev); 733 return(rootdev); 734 } 735