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 <sys/limits.h> 43 #include <stand.h> 44 #include <machine/bootinfo.h> 45 #include <stdarg.h> 46 47 #include <bootstrap.h> 48 #include <btxv86.h> 49 #include <edd.h> 50 #include "disk.h" 51 #include "libi386.h" 52 53 #define BIOS_NUMDRIVES 0x475 54 #define BIOSDISK_SECSIZE 512 55 #define BUFSIZE (1 * BIOSDISK_SECSIZE) 56 57 #define DT_ATAPI 0x10 /* disk type for ATAPI floppies */ 58 #define WDMAJOR 0 /* major numbers for devices we frontend for */ 59 #define WFDMAJOR 1 60 #define FDMAJOR 2 61 #define DAMAJOR 4 62 63 #ifdef DISK_DEBUG 64 #define DEBUG(fmt, args...) printf("%s: " fmt "\n", __func__, ## args) 65 #else 66 #define DEBUG(fmt, args...) 67 #endif 68 69 /* 70 * List of BIOS devices, translation from disk unit number to 71 * BIOS unit number. 72 */ 73 static struct bdinfo 74 { 75 int bd_unit; /* BIOS unit number */ 76 int bd_cyl; /* BIOS geometry */ 77 int bd_hds; 78 int bd_sec; 79 int bd_flags; 80 #define BD_MODEINT13 0x0000 81 #define BD_MODEEDD1 0x0001 82 #define BD_MODEEDD3 0x0002 83 #define BD_MODEMASK 0x0003 84 #define BD_FLOPPY 0x0004 85 int bd_type; /* BIOS 'drive type' (floppy only) */ 86 uint16_t bd_sectorsize; /* Sector size */ 87 uint64_t bd_sectors; /* Disk size */ 88 int bd_open; /* reference counter */ 89 void *bd_bcache; /* buffer cache data */ 90 } bdinfo [MAXBDDEV]; 91 static int nbdinfo = 0; 92 93 #define BD(dev) (bdinfo[(dev)->dd.d_unit]) 94 95 static void bd_io_workaround(struct disk_devdesc *dev); 96 97 static int bd_read(struct disk_devdesc *dev, daddr_t dblk, int blks, 98 caddr_t dest); 99 static int bd_write(struct disk_devdesc *dev, daddr_t dblk, int blks, 100 caddr_t dest); 101 static int bd_int13probe(struct bdinfo *bd); 102 103 static int bd_init(void); 104 static int bd_strategy(void *devdata, int flag, daddr_t dblk, size_t size, 105 char *buf, size_t *rsize); 106 static int bd_realstrategy(void *devdata, int flag, daddr_t dblk, size_t size, 107 char *buf, size_t *rsize); 108 static int bd_open(struct open_file *f, ...); 109 static int bd_close(struct open_file *f); 110 static int bd_ioctl(struct open_file *f, u_long cmd, void *data); 111 static int bd_print(int verbose); 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 NULL 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 /* XXX we need "disk aliases" to make this simpler */ 179 printf("BIOS drive %c: is disk%d\n", (unit < 0x80) ? 180 ('A' + unit): ('C' + unit - 0x80), nbdinfo); 181 nbdinfo++; 182 if (base == 0x80) 183 nfd++; 184 } 185 } 186 bcache_add_dev(nbdinfo); 187 return (0); 188 } 189 190 /* 191 * Try to detect a device supported by the legacy int13 BIOS 192 */ 193 static int 194 bd_int13probe(struct bdinfo *bd) 195 { 196 struct edd_params params; 197 int ret = 1; /* assume success */ 198 199 v86.ctl = V86_FLAGS; 200 v86.addr = 0x13; 201 v86.eax = 0x800; 202 v86.edx = bd->bd_unit; 203 v86int(); 204 205 /* Don't error out if we get bad sector number, try EDD as well */ 206 if (V86_CY(v86.efl) || /* carry set */ 207 (v86.edx & 0xff) <= (unsigned)(bd->bd_unit & 0x7f)) /* unit # bad */ 208 return (0); /* skip device */ 209 210 if ((v86.ecx & 0x3f) == 0) /* absurd sector number */ 211 ret = 0; /* set error */ 212 213 /* Convert max cyl # -> # of cylinders */ 214 bd->bd_cyl = ((v86.ecx & 0xc0) << 2) + ((v86.ecx & 0xff00) >> 8) + 1; 215 /* Convert max head # -> # of heads */ 216 bd->bd_hds = ((v86.edx & 0xff00) >> 8) + 1; 217 bd->bd_sec = v86.ecx & 0x3f; 218 bd->bd_type = v86.ebx & 0xff; 219 bd->bd_flags |= BD_MODEINT13; 220 221 /* Calculate sectors count from the geometry */ 222 bd->bd_sectors = bd->bd_cyl * bd->bd_hds * bd->bd_sec; 223 bd->bd_sectorsize = BIOSDISK_SECSIZE; 224 DEBUG("unit 0x%x geometry %d/%d/%d", bd->bd_unit, bd->bd_cyl, 225 bd->bd_hds, bd->bd_sec); 226 227 /* Determine if we can use EDD with this device. */ 228 v86.ctl = V86_FLAGS; 229 v86.addr = 0x13; 230 v86.eax = 0x4100; 231 v86.edx = bd->bd_unit; 232 v86.ebx = 0x55aa; 233 v86int(); 234 if (V86_CY(v86.efl) || /* carry set */ 235 (v86.ebx & 0xffff) != 0xaa55 || /* signature */ 236 (v86.ecx & EDD_INTERFACE_FIXED_DISK) == 0) 237 return (ret); /* return code from int13 AH=08 */ 238 239 /* EDD supported */ 240 bd->bd_flags |= BD_MODEEDD1; 241 if ((v86.eax & 0xff00) >= 0x3000) 242 bd->bd_flags |= BD_MODEEDD3; 243 /* Get disk params */ 244 params.len = sizeof(struct edd_params); 245 v86.ctl = V86_FLAGS; 246 v86.addr = 0x13; 247 v86.eax = 0x4800; 248 v86.edx = bd->bd_unit; 249 v86.ds = VTOPSEG(¶ms); 250 v86.esi = VTOPOFF(¶ms); 251 v86int(); 252 if (!V86_CY(v86.efl)) { 253 uint64_t total; 254 255 /* 256 * Sector size must be a multiple of 512 bytes. 257 * An alternate test would be to check power of 2, 258 * powerof2(params.sector_size). 259 */ 260 if (params.sector_size % BIOSDISK_SECSIZE) 261 bd->bd_sectorsize = BIOSDISK_SECSIZE; 262 else 263 bd->bd_sectorsize = params.sector_size; 264 265 total = bd->bd_sectorsize * params.sectors; 266 if (params.sectors != 0) { 267 /* Only update if we did not overflow. */ 268 if (total > params.sectors) 269 bd->bd_sectors = params.sectors; 270 } 271 272 total = (uint64_t)params.cylinders * 273 params.heads * params.sectors_per_track; 274 if (total > 0 && bd->bd_sectors > total) 275 bd->bd_sectors = total; 276 277 ret = 1; 278 } 279 DEBUG("unit 0x%x flags %x, sectors %llu, sectorsize %u", 280 bd->bd_unit, bd->bd_flags, bd->bd_sectors, bd->bd_sectorsize); 281 return (ret); 282 } 283 284 /* 285 * Print information about disks 286 */ 287 static int 288 bd_print(int verbose) 289 { 290 static char line[80]; 291 struct disk_devdesc dev; 292 int i, ret = 0; 293 294 if (nbdinfo == 0) 295 return (0); 296 297 printf("%s devices:", biosdisk.dv_name); 298 if ((ret = pager_output("\n")) != 0) 299 return (ret); 300 301 for (i = 0; i < nbdinfo; i++) { 302 snprintf(line, sizeof(line), 303 " disk%d: BIOS drive %c (%ju X %u):\n", i, 304 (bdinfo[i].bd_unit < 0x80) ? ('A' + bdinfo[i].bd_unit): 305 ('C' + bdinfo[i].bd_unit - 0x80), 306 (uintmax_t)bdinfo[i].bd_sectors, 307 bdinfo[i].bd_sectorsize); 308 if ((ret = pager_output(line)) != 0) 309 break; 310 dev.dd.d_dev = &biosdisk; 311 dev.dd.d_unit = i; 312 dev.d_slice = -1; 313 dev.d_partition = -1; 314 if (disk_open(&dev, 315 bdinfo[i].bd_sectorsize * bdinfo[i].bd_sectors, 316 bdinfo[i].bd_sectorsize) == 0) { 317 snprintf(line, sizeof(line), " disk%d", i); 318 ret = disk_print(&dev, line, verbose); 319 disk_close(&dev); 320 if (ret != 0) 321 return (ret); 322 } 323 } 324 return (ret); 325 } 326 327 /* 328 * Attempt to open the disk described by (dev) for use by (f). 329 * 330 * Note that the philosophy here is "give them exactly what 331 * they ask for". This is necessary because being too "smart" 332 * about what the user might want leads to complications. 333 * (eg. given no slice or partition value, with a disk that is 334 * sliced - are they after the first BSD slice, or the DOS 335 * slice before it?) 336 */ 337 static int 338 bd_open(struct open_file *f, ...) 339 { 340 struct disk_devdesc *dev; 341 struct disk_devdesc disk; 342 va_list ap; 343 uint64_t size; 344 int rc; 345 346 va_start(ap, f); 347 dev = va_arg(ap, struct disk_devdesc *); 348 va_end(ap); 349 350 if (dev->dd.d_unit < 0 || dev->dd.d_unit >= nbdinfo) 351 return (EIO); 352 BD(dev).bd_open++; 353 if (BD(dev).bd_bcache == NULL) 354 BD(dev).bd_bcache = bcache_allocate(); 355 356 /* 357 * Read disk size from partition. 358 * This is needed to work around buggy BIOS systems returning 359 * wrong (truncated) disk media size. 360 * During bd_probe() we tested if the mulitplication of bd_sectors 361 * would overflow so it should be safe to perform here. 362 */ 363 disk.dd.d_dev = dev->dd.d_dev; 364 disk.dd.d_unit = dev->dd.d_unit; 365 disk.d_slice = -1; 366 disk.d_partition = -1; 367 disk.d_offset = 0; 368 369 if (disk_open(&disk, BD(dev).bd_sectors * BD(dev).bd_sectorsize, 370 BD(dev).bd_sectorsize) == 0) { 371 372 if (disk_ioctl(&disk, DIOCGMEDIASIZE, &size) == 0) { 373 size /= BD(dev).bd_sectorsize; 374 if (size > BD(dev).bd_sectors) 375 BD(dev).bd_sectors = size; 376 } 377 disk_close(&disk); 378 } 379 380 rc = disk_open(dev, BD(dev).bd_sectors * BD(dev).bd_sectorsize, 381 BD(dev).bd_sectorsize); 382 if (rc != 0) { 383 BD(dev).bd_open--; 384 if (BD(dev).bd_open == 0) { 385 bcache_free(BD(dev).bd_bcache); 386 BD(dev).bd_bcache = NULL; 387 } 388 } 389 390 return (rc); 391 } 392 393 static int 394 bd_close(struct open_file *f) 395 { 396 struct disk_devdesc *dev; 397 398 dev = (struct disk_devdesc *)f->f_devdata; 399 BD(dev).bd_open--; 400 if (BD(dev).bd_open == 0) { 401 bcache_free(BD(dev).bd_bcache); 402 BD(dev).bd_bcache = NULL; 403 } 404 return (disk_close(dev)); 405 } 406 407 static int 408 bd_ioctl(struct open_file *f, u_long cmd, void *data) 409 { 410 struct disk_devdesc *dev; 411 int rc; 412 413 dev = (struct disk_devdesc *)f->f_devdata; 414 415 rc = disk_ioctl(dev, cmd, data); 416 if (rc != ENOTTY) 417 return (rc); 418 419 switch (cmd) { 420 case DIOCGSECTORSIZE: 421 *(uint32_t *)data = BD(dev).bd_sectorsize; 422 break; 423 case DIOCGMEDIASIZE: 424 *(uint64_t *)data = BD(dev).bd_sectors * BD(dev).bd_sectorsize; 425 break; 426 default: 427 return (ENOTTY); 428 } 429 return (0); 430 } 431 432 static int 433 bd_strategy(void *devdata, int rw, daddr_t dblk, size_t size, 434 char *buf, size_t *rsize) 435 { 436 struct bcache_devdata bcd; 437 struct disk_devdesc *dev; 438 439 dev = (struct disk_devdesc *)devdata; 440 bcd.dv_strategy = bd_realstrategy; 441 bcd.dv_devdata = devdata; 442 bcd.dv_cache = BD(dev).bd_bcache; 443 return (bcache_strategy(&bcd, rw, dblk + dev->d_offset, size, 444 buf, rsize)); 445 } 446 447 static int 448 bd_realstrategy(void *devdata, int rw, daddr_t dblk, size_t size, 449 char *buf, size_t *rsize) 450 { 451 struct disk_devdesc *dev = (struct disk_devdesc *)devdata; 452 uint64_t disk_blocks; 453 int blks, rc; 454 #ifdef BD_SUPPORT_FRAGS /* XXX: sector size */ 455 char fragbuf[BIOSDISK_SECSIZE]; 456 size_t fragsize; 457 458 fragsize = size % BIOSDISK_SECSIZE; 459 #else 460 if (size % BD(dev).bd_sectorsize) { 461 panic("bd_strategy: %d bytes I/O not multiple of block size", 462 size); 463 } 464 #endif 465 466 DEBUG("open_disk %p", dev); 467 468 /* 469 * Check the value of the size argument. We do have quite small 470 * heap (64MB), but we do not know good upper limit, so we check against 471 * INT_MAX here. This will also protect us against possible overflows 472 * while translating block count to bytes. 473 */ 474 if (size > INT_MAX) { 475 DEBUG("too large read: %zu bytes", size); 476 return (EIO); 477 } 478 479 blks = size / BD(dev).bd_sectorsize; 480 if (dblk > dblk + blks) 481 return (EIO); 482 483 if (rsize) 484 *rsize = 0; 485 486 /* 487 * Get disk blocks, this value is either for whole disk or for 488 * partition. 489 */ 490 if (disk_ioctl(dev, DIOCGMEDIASIZE, &disk_blocks) == 0) { 491 /* DIOCGMEDIASIZE returns bytes. */ 492 disk_blocks /= BD(dev).bd_sectorsize; 493 } else { 494 /* We should not get here. Just try to survive. */ 495 disk_blocks = BD(dev).bd_sectors - dev->d_offset; 496 } 497 498 /* Validate source block address. */ 499 if (dblk < dev->d_offset || dblk >= dev->d_offset + disk_blocks) 500 return (EIO); 501 502 /* 503 * Truncate if we are crossing disk or partition end. 504 */ 505 if (dblk + blks >= dev->d_offset + disk_blocks) { 506 blks = dev->d_offset + disk_blocks - dblk; 507 size = blks * BD(dev).bd_sectorsize; 508 DEBUG("short read %d", blks); 509 } 510 511 switch (rw & F_MASK) { 512 case F_READ: 513 DEBUG("read %d from %lld to %p", blks, dblk, buf); 514 515 if (blks && (rc = bd_read(dev, dblk, blks, buf))) { 516 /* Filter out floppy controller errors */ 517 if (BD(dev).bd_flags != BD_FLOPPY || rc != 0x20) { 518 printf("read %d from %lld to %p, error: 0x%x\n", 519 blks, dblk, buf, rc); 520 } 521 return (EIO); 522 } 523 #ifdef BD_SUPPORT_FRAGS /* XXX: sector size */ 524 DEBUG("bd_strategy: frag read %d from %d+%d to %p", 525 fragsize, dblk, blks, buf + (blks * BIOSDISK_SECSIZE)); 526 if (fragsize && bd_read(od, dblk + blks, 1, fragsize)) { 527 DEBUG("frag read error"); 528 return (EIO); 529 } 530 bcopy(fragbuf, buf + (blks * BIOSDISK_SECSIZE), fragsize); 531 #endif 532 break; 533 case F_WRITE : 534 DEBUG("write %d from %lld to %p", blks, dblk, buf); 535 536 if (blks && bd_write(dev, dblk, blks, buf)) { 537 DEBUG("write error"); 538 return (EIO); 539 } 540 #ifdef BD_SUPPORT_FRAGS 541 if (fragsize) { 542 DEBUG("Attempted to write a frag"); 543 return (EIO); 544 } 545 #endif 546 break; 547 default: 548 /* DO NOTHING */ 549 return (EROFS); 550 } 551 552 if (rsize) 553 *rsize = size; 554 return (0); 555 } 556 557 static int 558 bd_edd_io(struct disk_devdesc *dev, daddr_t dblk, int blks, caddr_t dest, 559 int dowrite) 560 { 561 static struct edd_packet packet; 562 563 packet.len = sizeof(struct edd_packet); 564 packet.count = blks; 565 packet.off = VTOPOFF(dest); 566 packet.seg = VTOPSEG(dest); 567 packet.lba = dblk; 568 v86.ctl = V86_FLAGS; 569 v86.addr = 0x13; 570 /* Should we Write with verify ?? 0x4302 ? */ 571 if (dowrite) 572 v86.eax = 0x4300; 573 else 574 v86.eax = 0x4200; 575 v86.edx = BD(dev).bd_unit; 576 v86.ds = VTOPSEG(&packet); 577 v86.esi = VTOPOFF(&packet); 578 v86int(); 579 if (V86_CY(v86.efl)) 580 return (v86.eax >> 8); 581 return (0); 582 } 583 584 static int 585 bd_chs_io(struct disk_devdesc *dev, daddr_t dblk, int blks, caddr_t dest, 586 int dowrite) 587 { 588 uint32_t x, bpc, cyl, hd, sec; 589 590 bpc = BD(dev).bd_sec * BD(dev).bd_hds; /* blocks per cylinder */ 591 x = dblk; 592 cyl = x / bpc; /* block # / blocks per cylinder */ 593 x %= bpc; /* block offset into cylinder */ 594 hd = x / BD(dev).bd_sec; /* offset / blocks per track */ 595 sec = x % BD(dev).bd_sec; /* offset into track */ 596 597 /* correct sector number for 1-based BIOS numbering */ 598 sec++; 599 600 if (cyl > 1023) { 601 /* CHS doesn't support cylinders > 1023. */ 602 return (1); 603 } 604 605 v86.ctl = V86_FLAGS; 606 v86.addr = 0x13; 607 if (dowrite) 608 v86.eax = 0x300 | blks; 609 else 610 v86.eax = 0x200 | blks; 611 v86.ecx = ((cyl & 0xff) << 8) | ((cyl & 0x300) >> 2) | sec; 612 v86.edx = (hd << 8) | BD(dev).bd_unit; 613 v86.es = VTOPSEG(dest); 614 v86.ebx = VTOPOFF(dest); 615 v86int(); 616 if (V86_CY(v86.efl)) 617 return (v86.eax >> 8); 618 return (0); 619 } 620 621 static void 622 bd_io_workaround(struct disk_devdesc *dev) 623 { 624 uint8_t buf[8 * 1024]; 625 626 bd_edd_io(dev, 0xffffffff, 1, (caddr_t)buf, 0); 627 } 628 629 630 static int 631 bd_io(struct disk_devdesc *dev, daddr_t dblk, int blks, caddr_t dest, 632 int dowrite) 633 { 634 u_int x, sec, result, resid, retry, maxfer; 635 caddr_t p, xp, bbuf; 636 637 /* Just in case some idiot actually tries to read/write -1 blocks... */ 638 if (blks < 0) 639 return (-1); 640 641 resid = blks; 642 p = dest; 643 644 /* 645 * Workaround for a problem with some HP ProLiant BIOS failing to work 646 * out the boot disk after installation. hrs and kuriyama discovered 647 * this problem with an HP ProLiant DL320e Gen 8 with a 3TB HDD, and 648 * discovered that an int13h call seems to cause a buffer overrun in 649 * the bios. The problem is alleviated by doing an extra read before 650 * the buggy read. It is not immediately known whether other models 651 * are similarly affected. 652 */ 653 if (dblk >= 0x100000000) 654 bd_io_workaround(dev); 655 656 /* Decide whether we have to bounce */ 657 if (VTOP(dest) >> 20 != 0 || (BD(dev).bd_unit < 0x80 && 658 (VTOP(dest) >> 16) != 659 (VTOP(dest + blks * BD(dev).bd_sectorsize) >> 16))) { 660 661 /* 662 * There is a 64k physical boundary somewhere in the 663 * destination buffer, or the destination buffer is above 664 * first 1MB of physical memory so we have to arrange a 665 * suitable bounce buffer. Allocate a buffer twice as large 666 * as we need to. Use the bottom half unless there is a break 667 * there, in which case we use the top half. 668 */ 669 x = V86_IO_BUFFER_SIZE / BD(dev).bd_sectorsize; 670 x = min(x, (unsigned)blks); 671 bbuf = PTOV(V86_IO_BUFFER); 672 maxfer = x; /* limit transfers to bounce region size */ 673 } else { 674 bbuf = NULL; 675 maxfer = 0; 676 } 677 678 while (resid > 0) { 679 /* 680 * Play it safe and don't cross track boundaries. 681 * (XXX this is probably unnecessary) 682 */ 683 sec = dblk % BD(dev).bd_sec; /* offset into track */ 684 x = min(BD(dev).bd_sec - sec, resid); 685 if (maxfer > 0) 686 x = min(x, maxfer); /* fit bounce buffer */ 687 688 /* where do we transfer to? */ 689 xp = bbuf == NULL ? p : bbuf; 690 691 /* 692 * Put your Data In, Put your Data out, 693 * Put your Data In, and shake it all about 694 */ 695 if (dowrite && bbuf != NULL) 696 bcopy(p, bbuf, x * BD(dev).bd_sectorsize); 697 698 /* 699 * Loop retrying the operation a couple of times. The BIOS 700 * may also retry. 701 */ 702 for (retry = 0; retry < 3; retry++) { 703 /* if retrying, reset the drive */ 704 if (retry > 0) { 705 v86.ctl = V86_FLAGS; 706 v86.addr = 0x13; 707 v86.eax = 0; 708 v86.edx = BD(dev).bd_unit; 709 v86int(); 710 } 711 712 if (BD(dev).bd_flags & BD_MODEEDD1) 713 result = bd_edd_io(dev, dblk, x, xp, dowrite); 714 else 715 result = bd_chs_io(dev, dblk, x, xp, dowrite); 716 if (result == 0) 717 break; 718 } 719 720 if (dowrite) 721 DEBUG("Write %d sector(s) from %p (0x%x) to %lld %s", x, 722 p, VTOP(p), dblk, result ? "failed" : "ok"); 723 else 724 DEBUG("Read %d sector(s) from %lld to %p (0x%x) %s", x, 725 dblk, p, VTOP(p), result ? "failed" : "ok"); 726 if (result) { 727 return (result); 728 } 729 if (!dowrite && bbuf != NULL) 730 bcopy(bbuf, p, x * BD(dev).bd_sectorsize); 731 p += (x * BD(dev).bd_sectorsize); 732 dblk += x; 733 resid -= x; 734 } 735 736 return (0); 737 } 738 739 static int 740 bd_read(struct disk_devdesc *dev, daddr_t dblk, int blks, caddr_t dest) 741 { 742 743 return (bd_io(dev, dblk, blks, dest, 0)); 744 } 745 746 static int 747 bd_write(struct disk_devdesc *dev, daddr_t dblk, int blks, caddr_t dest) 748 { 749 750 return (bd_io(dev, dblk, blks, dest, 1)); 751 } 752 753 /* 754 * Return the BIOS geometry of a given "fixed drive" in a format 755 * suitable for the legacy bootinfo structure. Since the kernel is 756 * expecting raw int 0x13/0x8 values for N_BIOS_GEOM drives, we 757 * prefer to get the information directly, rather than rely on being 758 * able to put it together from information already maintained for 759 * different purposes and for a probably different number of drives. 760 * 761 * For valid drives, the geometry is expected in the format (31..0) 762 * "000000cc cccccccc hhhhhhhh 00ssssss"; and invalid drives are 763 * indicated by returning the geometry of a "1.2M" PC-format floppy 764 * disk. And, incidentally, what is returned is not the geometry as 765 * such but the highest valid cylinder, head, and sector numbers. 766 */ 767 uint32_t 768 bd_getbigeom(int bunit) 769 { 770 771 v86.ctl = V86_FLAGS; 772 v86.addr = 0x13; 773 v86.eax = 0x800; 774 v86.edx = 0x80 + bunit; 775 v86int(); 776 if (V86_CY(v86.efl)) 777 return (0x4f010f); 778 return (((v86.ecx & 0xc0) << 18) | ((v86.ecx & 0xff00) << 8) | 779 (v86.edx & 0xff00) | (v86.ecx & 0x3f)); 780 } 781 782 /* 783 * Return a suitable dev_t value for (dev). 784 * 785 * In the case where it looks like (dev) is a SCSI disk, we allow the number of 786 * IDE disks to be specified in $num_ide_disks. There should be a Better Way. 787 */ 788 int 789 bd_getdev(struct i386_devdesc *d) 790 { 791 struct disk_devdesc *dev; 792 int biosdev; 793 int major; 794 int rootdev; 795 char *nip, *cp; 796 int i, unit; 797 798 dev = (struct disk_devdesc *)d; 799 biosdev = bd_unit2bios(dev->dd.d_unit); 800 DEBUG("unit %d BIOS device %d", dev->dd.d_unit, biosdev); 801 if (biosdev == -1) /* not a BIOS device */ 802 return (-1); 803 if (disk_open(dev, BD(dev).bd_sectors * BD(dev).bd_sectorsize, 804 BD(dev).bd_sectorsize) != 0) /* oops, not a viable device */ 805 return (-1); 806 else 807 disk_close(dev); 808 809 if (biosdev < 0x80) { 810 /* floppy (or emulated floppy) or ATAPI device */ 811 if (bdinfo[dev->dd.d_unit].bd_type == DT_ATAPI) { 812 /* is an ATAPI disk */ 813 major = WFDMAJOR; 814 } else { 815 /* is a floppy disk */ 816 major = FDMAJOR; 817 } 818 } else { 819 /* assume an IDE disk */ 820 major = WDMAJOR; 821 } 822 /* default root disk unit number */ 823 unit = biosdev & 0x7f; 824 825 /* XXX a better kludge to set the root disk unit number */ 826 if ((nip = getenv("root_disk_unit")) != NULL) { 827 i = strtol(nip, &cp, 0); 828 /* check for parse error */ 829 if ((cp != nip) && (*cp == 0)) 830 unit = i; 831 } 832 833 rootdev = MAKEBOOTDEV(major, dev->d_slice + 1, unit, dev->d_partition); 834 DEBUG("dev is 0x%x\n", rootdev); 835 return (rootdev); 836 } 837