usr/src/boot/sys/boot/i386/libi386/bioscd.c

   1 /*-
   2  * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
   3  * Copyright (c) 2001 John H. Baldwin <jhb@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
  30 /*
  31  * BIOS CD device handling for CD's that have been booted off of via no
  32  * emulation booting as defined in the El Torito standard.
  33  *
  34  * Ideas and algorithms from:
  35  *
  36  * - FreeBSD libi386/biosdisk.c
  37  *
  38  */
  39
  40 #include <stand.h>
  41
  42 #include <sys/param.h>
  43 #include <machine/bootinfo.h>
  44
  45 #include <stdarg.h>
  46
  47 #include <bootstrap.h>
  48 #include <btxv86.h>
  49 #include <edd.h>
  50 #include "libi386.h"
  51
  52 #define BIOSCD_SECSIZE          2048
  53 #define BUFSIZE                 (1 * BIOSCD_SECSIZE)
  54 #define MAXBCDEV                1
  55
  56 /* Major numbers for devices we frontend for. */
  57 #define ACDMAJOR                117
  58 #define CDMAJOR                 15
  59
  60 #ifdef DISK_DEBUG
  61 # define DEBUG(fmt, args...)    printf("%s: " fmt "\n" , __func__ , ## args)
  62 #else
  63 # define DEBUG(fmt, args...)
  64 #endif
  65
  66 struct specification_packet {
  67         u_char  sp_size;
  68         u_char  sp_bootmedia;
  69         u_char  sp_drive;
  70         u_char  sp_controller;
  71         u_int   sp_lba;
  72         u_short sp_devicespec;
  73         u_short sp_buffersegment;
  74         u_short sp_loadsegment;
  75         u_short sp_sectorcount;
  76         u_short sp_cylsec;
  77         u_char  sp_head;
  78 };
  79
  80 /*
  81  * List of BIOS devices, translation from disk unit number to
  82  * BIOS unit number.
  83  */
  84 static struct bcinfo {
  85         int     bc_unit;                /* BIOS unit number */
  86         struct specification_packet bc_sp;
  87         int     bc_open;                /* reference counter */
  88         void    *bc_bcache;             /* buffer cache data */
  89 } bcinfo [MAXBCDEV];
  90 static int nbcinfo = 0;
  91
  92 #define BC(dev) (bcinfo[(dev)->d_unit])
  93
  94 static int      bc_read(int unit, daddr_t dblk, int blks, caddr_t dest);
  95 static int      bc_init(void);
  96 static int      bc_strategy(void *devdata, int flag, daddr_t dblk,
  97     size_t size, char *buf, size_t *rsize);
  98 static int      bc_realstrategy(void *devdata, int flag, daddr_t dblk,
  99     size_t size, char *buf, size_t *rsize);
 100 static int      bc_open(struct open_file *f, ...);
 101 static int      bc_close(struct open_file *f);
 102 static int      bc_print(int verbose);
 103
 104 struct devsw bioscd = {
 105         "cd",
 106         DEVT_CD,
 107         bc_init,
 108         bc_strategy,
 109         bc_open,
 110         bc_close,
 111         noioctl,
 112         bc_print,
 113         NULL
 114 };
 115
 116 /*
 117  * Translate between BIOS device numbers and our private unit numbers.
 118  */
 119 int
 120 bc_bios2unit(int biosdev)
 121 {
 122         int i;
 123
 124         DEBUG("looking for bios device 0x%x", biosdev);
 125         for (i = 0; i < nbcinfo; i++) {
 126                 DEBUG("bc unit %d is BIOS device 0x%x", i, bcinfo[i].bc_unit);
 127                 if (bcinfo[i].bc_unit == biosdev)
 128                         return(i);
 129         }
 130         return(-1);
 131 }
 132
 133 int
 134 bc_unit2bios(int unit)
 135 {
 136         if ((unit >= 0) && (unit < nbcinfo))
 137                 return(bcinfo[unit].bc_unit);
 138         return(-1);
 139 }
 140
 141 /*
 142  * We can't quiz, we have to be told what device to use, so this functoin
 143  * doesn't do anything.  Instead, the loader calls bc_add() with the BIOS
 144  * device number to add.
 145  */
 146 static int
 147 bc_init(void)
 148 {
 149
 150         return (0);
 151 }
 152
 153 int
 154 bc_add(int biosdev)
 155 {
 156
 157         if (nbcinfo >= MAXBCDEV)
 158                 return (-1);
 159         bcinfo[nbcinfo].bc_unit = biosdev;
 160         v86.ctl = V86_FLAGS;
 161         v86.addr = 0x13;
 162         v86.eax = 0x4b01;
 163         v86.edx = biosdev;
 164         v86.ds = VTOPSEG(&bcinfo[nbcinfo].bc_sp);
 165         v86.esi = VTOPOFF(&bcinfo[nbcinfo].bc_sp);
 166         v86int();
 167         if ((v86.eax & 0xff00) != 0)
 168                 return (-1);
 169
 170         printf("BIOS CD is cd%d\n", nbcinfo);
 171         nbcinfo++;
 172         bcache_add_dev(nbcinfo);        /* register cd device in bcache */
 173         return(0);
 174 }
 175
 176 /*
 177  * Print information about disks
 178  */
 179 static int
 180 bc_print(int verbose)
 181 {
 182         char line[80];
 183         int i, ret = 0;
 184
 185         if (nbcinfo == 0)
 186                 return (0);
 187
 188         printf("%s devices:", bioscd.dv_name);
 189         if ((ret = pager_output("\n")) != 0)
 190                 return (ret);
 191
 192         for (i = 0; i < nbcinfo; i++) {
 193                 sprintf(line, "    cd%d: Device 0x%x\n", i,
 194                     bcinfo[i].bc_sp.sp_devicespec);
 195                 ret = pager_output(line);
 196                 if (ret != 0)
 197                         return (ret);
 198         }
 199         return (ret);
 200 }
 201
 202 /*
 203  * Attempt to open the disk described by (dev) for use by (f).
 204  */
 205 static int
 206 bc_open(struct open_file *f, ...)
 207 {
 208         va_list ap;
 209         struct i386_devdesc *dev;
 210
 211         va_start(ap, f);
 212         dev = va_arg(ap, struct i386_devdesc *);
 213         va_end(ap);
 214         if (dev->d_unit >= nbcinfo) {
 215                 DEBUG("attempt to open nonexistent disk");
 216                 return(ENXIO);
 217         }
 218
 219         BC(dev).bc_open++;
 220         if (BC(dev).bc_bcache == NULL)
 221             BC(dev).bc_bcache = bcache_allocate();
 222         return(0);
 223 }
 224
 225 static int
 226 bc_close(struct open_file *f)
 227 {
 228         struct i386_devdesc *dev;
 229
 230         dev = (struct i386_devdesc *)f->f_devdata;
 231         BC(dev).bc_open--;
 232         if (BC(dev).bc_open == 0) {
 233             bcache_free(BC(dev).bc_bcache);
 234             BC(dev).bc_bcache = NULL;
 235         }
 236         return(0);
 237 }
 238
 239 static int
 240 bc_strategy(void *devdata, int rw, daddr_t dblk, size_t size,
 241     char *buf, size_t *rsize)
 242 {
 243         struct bcache_devdata bcd;
 244         struct i386_devdesc *dev;
 245
 246         dev = (struct i386_devdesc *)devdata;
 247         bcd.dv_strategy = bc_realstrategy;
 248         bcd.dv_devdata = devdata;
 249         bcd.dv_cache = BC(dev).bc_bcache;
 250
 251         return (bcache_strategy(&bcd, rw, dblk, size, buf, rsize));
 252 }
 253
 254 static int
 255 bc_realstrategy(void *devdata, int rw, daddr_t dblk, size_t size,
 256     char *buf, size_t *rsize)
 257 {
 258         struct i386_devdesc *dev;
 259         int unit;
 260         int blks;
 261 #ifdef BD_SUPPORT_FRAGS
 262         char fragbuf[BIOSCD_SECSIZE];
 263         size_t fragsize;
 264
 265         fragsize = size % BIOSCD_SECSIZE;
 266 #else
 267         if (size % BIOSCD_SECSIZE)
 268                 return (EINVAL);
 269 #endif
 270
 271         if ((rw & F_MASK) != F_READ)
 272                 return(EROFS);
 273         dev = (struct i386_devdesc *)devdata;
 274         unit = dev->d_unit;
 275         blks = size / BIOSCD_SECSIZE;
 276         if (dblk % (BIOSCD_SECSIZE / DEV_BSIZE) != 0)
 277                 return (EINVAL);
 278         dblk /= (BIOSCD_SECSIZE / DEV_BSIZE);
 279         DEBUG("read %d from %lld to %p", blks, dblk, buf);
 280
 281         if (rsize)
 282                 *rsize = 0;
 283         if ((blks = bc_read(unit, dblk, blks, buf)) < 0) {
 284                 DEBUG("read error");
 285                 return (EIO);
 286         } else {
 287                 if (size / BIOSCD_SECSIZE > blks) {
 288                         if (rsize)
 289                                 *rsize = blks * BIOSCD_SECSIZE;
 290                         return (0);
 291                 }
 292         }
 293 #ifdef BD_SUPPORT_FRAGS
 294         DEBUG("frag read %d from %lld+%d to %p",
 295             fragsize, dblk, blks, buf + (blks * BIOSCD_SECSIZE));
 296         if (fragsize && bc_read(unit, dblk + blks, 1, fragbuf) != 1) {
 297                 if (blks) {
 298                         if (rsize)
 299                                 *rsize = blks * BIOSCD_SECSIZE;
 300                         return (0);
 301                 }
 302                 DEBUG("frag read error");
 303                 return(EIO);
 304         }
 305         bcopy(fragbuf, buf + (blks * BIOSCD_SECSIZE), fragsize);
 306 #endif
 307         if (rsize)
 308                 *rsize = size;
 309         return (0);
 310 }
 311
 312 /* return negative value for an error, otherwise blocks read */
 313 static int
 314 bc_read(int unit, daddr_t dblk, int blks, caddr_t dest)
 315 {
 316         u_int maxfer, resid, result, retry, x;
 317         caddr_t bbuf, p, xp;
 318         static struct edd_packet packet;
 319         int biosdev;
 320 #ifdef DISK_DEBUG
 321         int error;
 322 #endif
 323
 324         /* Just in case some idiot actually tries to read -1 blocks... */
 325         if (blks < 0)
 326                 return (-1);
 327
 328         /* If nothing to do, just return succcess. */
 329         if (blks == 0)
 330                 return (0);
 331
 332         /* Decide whether we have to bounce */
 333         if (VTOP(dest) >> 20 != 0) {
 334                 /*
 335                  * The destination buffer is above first 1MB of
 336                  * physical memory so we have to arrange a suitable
 337                  * bounce buffer.
 338                  */
 339                 x = V86_IO_BUFFER_SIZE / BIOSCD_SECSIZE;
 340                 if (x == 0)
 341                         panic("BUG: Real mode buffer is too small\n");
 342                 x = min(x, (unsigned)blks);
 343                 bbuf = PTOV(V86_IO_BUFFER);
 344                 maxfer = x;
 345         } else {
 346                 bbuf = NULL;
 347                 maxfer = 0;
 348         }
 349
 350         biosdev = bc_unit2bios(unit);
 351         resid = blks;
 352         p = dest;
 353
 354         while (resid > 0) {
 355                 if (bbuf)
 356                         xp = bbuf;
 357                 else
 358                         xp = p;
 359                 x = resid;
 360                 if (maxfer > 0)
 361                         x = min(x, maxfer);
 362
 363                 /*
 364                  * Loop retrying the operation a couple of times.  The BIOS
 365                  * may also retry.
 366                  */
 367                 for (retry = 0; retry < 3; retry++) {
 368                         /* If retrying, reset the drive */
 369                         if (retry > 0) {
 370                                 v86.ctl = V86_FLAGS;
 371                                 v86.addr = 0x13;
 372                                 v86.eax = 0;
 373                                 v86.edx = biosdev;
 374                                 v86int();
 375                         }
 376
 377                         packet.len = sizeof(struct edd_packet);
 378                         packet.count = x;
 379                         packet.off = VTOPOFF(xp);
 380                         packet.seg = VTOPSEG(xp);
 381                         packet.lba = dblk;
 382                         v86.ctl = V86_FLAGS;
 383                         v86.addr = 0x13;
 384                         v86.eax = 0x4200;
 385                         v86.edx = biosdev;
 386                         v86.ds = VTOPSEG(&packet);
 387                         v86.esi = VTOPOFF(&packet);
 388                         v86int();
 389                         result = V86_CY(v86.efl);
 390                         if (result == 0)
 391                                 break;
 392                         /* fall back to 1 sector read */
 393                         x = 1;
 394                 }
 395
 396 #ifdef DISK_DEBUG
 397                 error = (v86.eax >> 8) & 0xff;
 398 #endif
 399                 DEBUG("%d sectors from %lld to %p (0x%x) %s", x, dblk, p,
 400                     VTOP(p), result ? "failed" : "ok");
 401                 DEBUG("unit %d  status 0x%x", unit, error);
 402
 403                 /* still an error? break off */
 404                 if (result != 0)
 405                         break;
 406
 407                 if (bbuf != NULL)
 408                         bcopy(bbuf, p, x * BIOSCD_SECSIZE);
 409                 p += (x * BIOSCD_SECSIZE);
 410                 dblk += x;
 411                 resid -= x;
 412         }
 413
 414 /*      hexdump(dest, (blks * BIOSCD_SECSIZE)); */
 415
 416         if (blks - resid == 0)
 417                 return (-1);            /* read failed */
 418
 419         return (blks - resid);
 420 }
 421
 422 /*
 423  * Return a suitable dev_t value for (dev).
 424  */
 425 int
 426 bc_getdev(struct i386_devdesc *dev)
 427 {
 428     int biosdev, unit;
 429     int major;
 430     int rootdev;
 431
 432     unit = dev->d_unit;
 433     biosdev = bc_unit2bios(unit);
 434     DEBUG("unit %d BIOS device %d", unit, biosdev);
 435     if (biosdev == -1)                          /* not a BIOS device */
 436         return(-1);
 437
 438     /*
 439      * XXX: Need to examine device spec here to figure out if SCSI or
 440      * ATAPI.  No idea on how to figure out device number.  All we can
 441      * really pass to the kernel is what bus and device on which bus we
 442      * were booted from, which dev_t isn't well suited to since those
 443      * number don't match to unit numbers very well.  We may just need
 444      * to engage in a hack where we pass -C to the boot args if we are
 445      * the boot device.
 446      */
 447     major = ACDMAJOR;
 448     unit = 0;   /* XXX */
 449
 450     /* XXX: Assume partition 'a'. */
 451     rootdev = MAKEBOOTDEV(major, 0, unit, 0);
 452     DEBUG("dev is 0x%x\n", rootdev);
 453     return(rootdev);
 454 }